# -*- coding: utf-8 -*-

"""
Importing and Exporting
"""

from mathics.version import __version__  # noqa used in loading to check consistency.

from mathics.core.expression import (
    ByteArrayAtom,
    SymbolList,
    SymbolRule,
    Expression,
    from_python,
    strip_context,
    Symbol,
    SymbolFailed,
    SymbolNull,
)
from mathics.core.streams import stream_manager

from mathics.builtin.base import (
    Builtin,
    Predefined,
    String,
    Integer,
    get_option,
)

from mathics.builtin.pymimesniffer import magic
import mimetypes
import sys
from itertools import chain

try:
    import urllib.request as urllib2
    from urllib.error import HTTPError, URLError
except ImportError:
    import urllib2
    from urllib2 import HTTPError, URLError

mimetypes.add_type("application/vnd.wolfram.mathematica.package", ".m")

# Seems that JSON is not registered on the mathics.net server, so we do it manually here.
# Keep in mind that mimetypes has system-dependent aspects (it inspects "/etc/mime.types" and other files).
mimetypes.add_type("application/json", ".json")

# TODO: Add more file formats

mimetype_dict = {
    "application/dicom": "DICOM",
    "application/dbase": "DBF",
    "application/dbf": "DBF",
    "application/eps": "EPS",
    "application/fits": "FITS",
    "application/json": "JSON",
    "application/mathematica": "NB",
    "application/mdb": "MDB",
    "application/mbox": "MBOX",
    "application/msaccess": "MDB",
    "application/octet-stream": "OBJ",
    "application/pdf": "PDF",
    "application/pcx": "PCX",
    "application/postscript": "EPS",
    "application/rss+xml": "RSS",
    "application/rtf": "RTF",
    "application/sla": "STL",
    "application/tga": "TGA",
    "application/vnd.google-earth.kml+xml": "KML",
    "application/vnd.ms-excel": "XLS",
    "application/vnd.ms-pki.stl": "STL",
    "application/vnd.oasis.opendocument.spreadsheet": "ODS",
    "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet": "XLSX",  # nopep8
    "application/vnd.sun.xml.calc": "SXC",
    "application/vnd.msaccess": "MDB",
    "application/vnd.wolfram.cdf": "CDF",
    "application/vnd.wolfram.cdf.text": "CDF",
    "application/vnd.wolfram.mathematica.package": "Package",
    "application/xhtml+xml": "XHTML",
    "application/xml": "XML",
    "application/x-3ds": "3DS",
    "application/x-cdf": "NASACDF",
    "application/x-eps": "EPS",
    "application/x-flac": "FLAC",
    "application/x-font-bdf": "BDF",
    "application/x-hdf": "HDF",
    "application/x-msaccess": "MDB",
    "application/x-netcdf": "NetCDF",
    "application/x-shockwave-flash": "SWF",
    "application/x-tex": "TeX",  # Also TeX
    "audio/aiff": "AIFF",
    "audio/basic": "AU",  # Also SND
    "audio/midi": "MIDI",
    "audio/x-aifc": "AIFF",
    "audio/x-aiff": "AIFF",
    "audio/x-flac": "FLAC",
    "audio/x-wav": "WAV",
    "chemical/seq-na-genbank": "GenBank",
    "chemical/seq-aa-fasta": "FASTA",
    "chemical/seq-na-fasta": "FASTA",
    "chemical/seq-na-fastq": "FASTQ",
    "chemical/seq-na-sff": "SFF",
    "chemical/x-cif": "CIF",
    "chemical/x-daylight-smiles": "SMILES",
    "chemical/x-hin": "HIN",
    "chemical/x-jcamp-dx": "JCAMP-DX",
    "chemical/x-mdl-molfile": "MOL",
    "chemical/x-mdl-sdf": "SDF",
    "chemical/x-mdl-sdfile": "SDF",
    "chemical/x-mdl-tgf": "TGF",
    "chemical/x-mmcif": "CIF",
    "chemical/x-mol2": "MOL2",
    "chemical/x-mopac-input": "Table",
    "chemical/x-pdb": "PDB",
    "chemical/x-xyz": "XYZ",
    "image/bmp": "BMP",
    "image/eps": "EPS",
    "image/fits": "FITS",
    "image/gif": "GIF",
    "image/jp2": "JPEG2000",
    "image/jpeg": "JPEG",
    "image/pbm": "PNM",
    "image/pcx": "PCX",
    "image/pict": "PICT",
    "image/png": "PNG",
    "image/svg+xml": "SVG",
    "image/tga": "TGA",
    "image/tiff": "TIFF",
    "image/vnd.dxf": "DXF",
    "image/vnd.microsoft.icon": "ICO",
    "image/x-3ds": "3DS",
    "image/x-dxf": "DXF",
    "image/x-exr": "OpenEXR",
    "image/x-icon": "ICO",
    "image/x-ms-bmp": "BMP",
    "image/x-pcx": "PCX",
    "image/x-portable-anymap": "PNM",
    "image/x-portable-bitmap": "PBM",
    "image/x-portable-graymap": "PGM",
    "image/x-portable-pixmap": "PPM",
    "image/x-xbitmap": "XBM",
    "model/x3d+xml": "X3D",
    "model/vrml": "VRML",
    "model/x-lwo": "LWO",
    "model/x-pov": "POV",
    "text/calendar": "ICS",
    "text/comma-separated-values": "CSV",
    "text/csv": "CSV",
    "text/html": "HTML",
    "text/mathml": "MathML",
    "text/plain": "Text",
    "text/rtf": "RTF",
    "text/scriptlet": "SCT",
    "text/tab-separated-values": "TSV",
    "text/texmacs": "Text",
    "text/vnd.graphviz": "DOT",
    "text/x-csrc": "C",
    "text/x-tex": "TeX",
    "text/x-vcalendar": "VCS",
    "text/x-vcard": "VCF",
    "text/xml": "XML",
    "video/avi": "AVI",
    "video/quicktime": "QuickTime",
    "video/x-flv": "FLV",
    # None: 'Binary',
}

IMPORTERS = {}
EXPORTERS = {}
EXTENSIONMAPPINGS = {
    "*.3ds": "3DS",
    "*.3fr": "Raw",
    "*.aac": "M4A",
    "*.aco": "ACO",
    "*.aif": "AIFF",
    "*.aiff": "AIFF",
    "*.arw": "Raw",
    "*.au": "AU",
    "*.avi": "AVI",
    "*.b64": "BASE64",
    "*.bay": "Raw",
    "*.bdf": "BDF",
    "*.bmp": "BMP",
    "*.bmq": "Raw",
    "*.bson": "BSON",
    "*.byu": "BYU",
    "*.bz2": "BZIP2",
    "*.c": "C",
    "*.cdf": "CDF",
    "*.ch": "SCT",
    "*.cha": "HarwellBoeing",
    "*.che": "HarwellBoeing",
    "*.cif": "CIF",
    "*.cine": "Raw",
    "*.col": "DIMACS",
    "*.col.b": "DIMACS",
    "*.cr2": "Raw",
    "*.cra": "HarwellBoeing",
    "*.cre": "HarwellBoeing",
    "*.crw": "Raw",
    "*.cs1": "Raw",
    "*.csa": "HarwellBoeing",
    "*.cse": "HarwellBoeing",
    "*.css": "CSS",
    "*.css": "CSS",
    "*.csv": "CSV",
    "*.ct": "SCT",
    "*.cua": "HarwellBoeing",
    "*.cue": "HarwellBoeing",
    "*.cur": "CUR",
    "*.cza": "HarwellBoeing",
    "*.cze": "HarwellBoeing",
    "*.dae": "DAE",
    "*.dat": "Table",
    "*.dc2": "Raw",
    "*.dcm": "DICOM",
    "*.dcr": "Raw",
    "*.dib": "BMP",
    "*.dic": "DICOM",
    "*.dicm": "DICOM",
    "*.dif": "DIF",
    "*.dng": "Raw",
    "*.dot": "DOT",
    "*.dxf": "DXF",
    "*.edf": "EDF",
    "*.emf": "EMF",
    "*.eml": "EML",
    "*.enc": "UUE",
    "*.ent": "PDB",
    "*.eps": "EPS",
    "*.epsf": "EPS",
    "*.epsi": "EPS",
    "*.erf": "Raw",
    "*.fa": "FASTA",
    "*.fasta": "FASTA",
    "*.fastq": "FASTQ",
    "*.fcs": "FCS",
    "*.fff": "Raw",
    "*.fit": "FITS",
    "*.fits": "FITS",
    "*.flac": "FLAC",
    "*.flv": "FLV",
    "*.fmu": "FMU",
    "*.fq": "FASTQ",
    "*.fsa": "FASTA",
    "*.g6": "Graph6",
    "*.geojson": "GeoJSON",
    "*.gif": "GIF",
    "*.gml": "Graphlet",
    "*.graphml": "GraphML",
    "*.grb": "GRIB",
    "*.grd": "SurferGrid",
    "*.grib": "GRIB",
    "*.gv": "DOT",
    "*.gw": "LEDA",
    "*.gxl": "GXL",
    "*.gz": "GZIP",
    "*.h5": "HDF5",
    "*.hdf": "HDF",
    "*.hdr": "Raw",
    "*.hmm": "HMMER",
    "*.htm": "HTML",
    # "*.htm": "XHTML",
    "*.html": "HTML",
    # "*.html": "XHTML",
    "*.ia": "Raw",
    "*.icc": "ICC",
    "*.icm": "ICC",
    "*.icns": "ICNS",
    "*.ico": "ICO",
    "*.ics": "ICS",
    "*.ini": "INI",
    "*.j2k": "JPEG2000",
    "*.jar": "ZIP",
    "*.jfif": "JPEG",
    "*.jp2": "JPEG2000",
    "*.jpc": "JPEG2000",
    "*.jpeg": "JPEG",
    "*.jpg": "JPEG",
    "*.json": "JSON",
    "*.jvx": "JVX",
    "*.k25": "Raw",
    "*.kc2": "Raw",
    "*.kdc": "Raw",
    "*.kml": "KML",
    "*.kmz": "KML",
    "*.lgr": "LEDA",
    "*.lmd": "FCS",
    "*.lwo": "LWO",
    "*.m": "Package",
    "*.m4a": "M4A",
    "*.ma": "Maya",
    "*.mat": "MAT",
    "*.mbox": "MBOX",
    "*.mbx": "MBOX",
    "*.mdc": "Raw",
    "*.mef": "Raw",
    "*.mesh": "MESH",
    "*.mgf": "MGF",
    "*.mid": "MIDI",
    "*.mml": "MathML",
    "*.mo": "MO",
    "*.mol": "MOL",
    "*.mol2": "MOL2",
    "*.mos": "Raw",
    "*.mov": "QuickTime",
    "*.mp3": "MP3",
    "*.mpfa": "FASTA",
    "*.mrw": "Raw",
    "*.mtx": "MTX",
    "*.mulaw": "AU",
    "*.mx": "MX",
    "*.nb": "NB",
    "*.nc": "NETCDF",
    "*.ndk": "NDK",
    "*.nef": "Raw",
    "*.net": "PAJEK",
    "*.nex": "NEXUS",
    "*.noff": "NOFF",
    "*.nrw": "Raw",
    "*.nxs": "NEXUS",
    "*.obj": "OBJ",
    "*.ods": "ODS",
    "*.off": "OFF",
    "*.oga": "OGG",
    "*.ogg": "OGG",
    "*.orf": "Raw",
    "*.pbm": "PBM",
    "*.pct": "PICT",
    "*.pcx": "PCX",
    "*.pdb": "PDB",
    "*.pdf": "PDF",
    "*.pef": "Raw",
    "*.pgm": "PGM",
    "*.pha": "HarwellBoeing",
    "*.phe": "HarwellBoeing",
    "*.pic": "PICT",
    # "*.pic": "PXR",
    "*.pict": "PICT",
    "*.ply": "PLY",
    "*.png": "PNG",
    "*.pnm": "PNM",
    "*.pov": "POV",
    "*.ppm": "PPM",
    "*.pra": "HarwellBoeing",
    "*.pre": "HarwellBoeing",
    "*.properties": "JavaProperties",
    "*.psa": "HarwellBoeing",
    "*.pse": "HarwellBoeing",
    "*.pua": "HarwellBoeing",
    "*.pue": "HarwellBoeing",
    "*.pxn": "Raw",
    "*.pxr": "PXR",
    "*.pza": "HarwellBoeing",
    "*.pze": "HarwellBoeing",
    "*.qt": "QuickTime",
    "*.qtk": "Raw",
    "*.raf": "Raw",
    "*.raw": "Raw",
    # "*.raw": "RawBitmap",
    "*.rdc": "Raw",
    "*.rha": "HarwellBoeing",
    "*.rhe": "HarwellBoeing",
    "*.rib": "RIB",
    "*.rle": "RLE",
    "*.rra": "HarwellBoeing",
    "*.rre": "HarwellBoeing",
    "*.rsa": "HarwellBoeing",
    "*.rse": "HarwellBoeing",
    "*.rtf": "RTF",
    "*.rua": "HarwellBoeing",
    "*.rue": "HarwellBoeing",
    "*.rw2": "Raw",
    "*.rwl": "Raw",
    "*.rza": "HarwellBoeing",
    "*.rze": "HarwellBoeing",
    "*.s6": "Sparse6",
    "*.sct": "SCT",
    "*.sdf": "SDF",
    "*.sds": "HDF",
    "*.sff": "SFF",
    "*.sma": "SMA",
    "*.sme": "SME",
    "*.smi": "SMILES",
    "*.snd": "SND",
    "*.sp3": "SP3",
    "*.sr2": "Raw",
    "*.srf": "Raw",
    "*.sti": "Raw",
    "*.stl": "STL",
    "*.svg": "SVG",
    "*.svgz": "SVGZ",
    "*.swf": "SWF",
    "*.tar": "TAR",
    "*.tcx": "TCX",
    # "*.tcx": "TECHEXPLORER",
    "*.tex": "TeX",
    "*.tff": "TIFF",
    "*.tga": "TGA",
    "*.tgf": "TGF",
    "*.tgz": "GZIP",
    "*.tif": "TIFF",
    "*.tiff": "TIFF",
    "*.tsv": "TSV",
    "*.txt": "Text",
    "*.ubj": "UBJSON",
    "*.uue": "UUE",
    "*.vtk": "VTK",
    "*.w64": "Wave64",
    "*.wav": "WAV",
    "*.wdx": "WDX",
    "*.webp": "WebP",
    "*.wl": "Package",
    "*.wlnet": "WLNet",
    "*.wls": "Package",
    "*.wmf": "WMF",
    "*.wmlf": "WMLF",
    "*.wrl": "VRML",
    "*.wxf": "WXF",
    "*.x3d": "X3D",
    "*.x3f": "Raw",
    "*.xbm": "XBM",
    "*.xht": "XHTML",
    "*.xhtml": "XHTML",
    "*.xls": "XLS",
    "*.xlsx": "XLSX",
    # "*.xml": "ExpressionML",
    # "*.xml": "XHTML",
    # "*.xml": "XHTMLMathML",
    "*.xml": "XML",
    "*.xyz": "XYZ",
    "*.zip": "ZIP",
    "*.zpr": "ZPR",
}


FORMATMAPPINGS = {
    "3DS": "3DS",
    "ACO": "ACO",
    "AFFYMETRIX": "Affymetrix",
    "AGILENTMICROARRAY": "AgilentMicroarray",
    "AIFC": "AIFF",
    "AIFF": "AIFF",
    "APACHELOG": "ApacheLog",
    "APPLICATION/ACAD": "DXF",
    "APPLICATION/ACROBAT": "PDF",
    "APPLICATION/BMP": "BMP",
    "APPLICATION/CSV": "CSV",
    "APPLICATION/DICOM": "DICOM",
    "APPLICATION/DXF": "DXF",
    "APPLICATION/EMF": "EMF",
    "APPLICATION/EPS": "EPS",
    "APPLICATION/EXCEL": "XLS",
    # "APPLICATION/EXCEL": "XLSX",
    "APPLICATION/FITS": "FITS",
    "APPLICATION/GEO+JSON": "GeoJSON",
    "APPLICATION/JPG": "JPEG",
    "APPLICATION/JSON": "JSON",
    "APPLICATION/MATHEMATICA": "NB",
    "APPLICATION/MS-EXCEL": "XLS",
    # "APPLICATION/MS-EXCEL": "XLSX",
    "APPLICATION/MSWORD": "DOC",
    "APPLICATION/PCX": "PCX",
    "APPLICATION/PDF": "PDF",
    "APPLICATION/PNG": "PNG",
    "APPLICATION/POSTSCRIPT": "EPS",
    "APPLICATION/RTF": "RTF",
    "APPLICATION/SLA": "STL",
    "APPLICATION/TAR": "TAR",
    "APPLICATION/TGA": "TGA",
    "APPLICATION/TIF": "TIFF",
    "APPLICATION/TIFF": "TIFF",
    "APPLICATION/TXT": "Text",
    "APPLICATION/UBJSON": "UBJSON",
    "APPLICATION/VCARD": "VCF",
    "APPLICATION/VND.MS-EXCEL": "XLS",
    # "APPLICATION/VND.MS-EXCEL": "XLSX",
    "APPLICATION/VND.OASIS.OPENDOCUMENT.SPREADSHEET": "ODS",
    "APPLICATION/VND.PDF": "PDF",
    "APPLICATION/VND.TCPDUMP.PCAP": "PCAP",
    "APPLICATION/VND.WOLFRAM.CDF.TEXT": "CDF",
    "APPLICATION/VND.WOLFRAM.MATHEMATICA": "NB",
    "APPLICATION/VND.WOLFRAM.MATHEMATICA.PACKAGE": "Package",
    "APPLICATION/VND.WOLFRAM.PLAYER": "NB",
    "APPLICATION/WARC": "WARC",
    "APPLICATION/WMF": "WMF",
    "APPLICATION/X-3DS": "3DS",
    "APPLICATION/X-AUTOCAD": "DXF",
    "APPLICATION/X-BMP": "BMP",
    "APPLICATION/X-BZIP": "BZIP2",
    "APPLICATION/X-DOS_MS_EXCEL": "XLS",
    # "APPLICATION/X-DOS_MS_EXCEL": "XLSX",
    "APPLICATION/X-DXF": "DXF",
    "APPLICATION/X-EMF": "EMF",
    "APPLICATION/X-EPS": "EPS",
    "APPLICATION/X-EXCEL": "XLS",
    # "APPLICATION/X-EXCEL": "XLSX",
    "APPLICATION/X-GZIP": "GZIP",
    "APPLICATION/X-GZIP-COMPRESSED": "GZIP",
    "APPLICATION/X-HDF": "HDF",
    "APPLICATION/X-HDF5": "HDF5",
    "APPLICATION/X-JPG": "JPEG",
    "APPLICATION/X-LATEX": "LaTeX",
    "APPLICATION/X-MS-EXCEL": "XLS",
    # "APPLICATION/X-MS-EXCEL": "XLSX",
    "APPLICATION/X-MSEXCEL": "XLS",
    # "APPLICATION/X-MSEXCEL": "XLSX",
    "APPLICATION/X-MSMETAFILE": "WMF",
    "APPLICATION/X-PCAPNG": "PCAP",
    "APPLICATION/X-PCX": "PCX",
    "APPLICATION/X-PDF": "PDF",
    "APPLICATION/X-PNG": "PNG",
    "APPLICATION/X-RTF": "RTF",
    "APPLICATION/X-SHOCKWAVE-FLASH": "SWF",
    "APPLICATION/X-TAR": "TAR",
    "APPLICATION/X-TARGA": "TGA",
    "APPLICATION/X-TEX": "TeX",
    "APPLICATION/X-TGA": "TGA",
    "APPLICATION/X-TIF": "TIFF",
    "APPLICATION/X-TIFF": "TIFF",
    "APPLICATION/X-TROFF-MSVIDEO": "AVI",
    "APPLICATION/X-VND.OASIS.OPENDOCUMENT.SPREADSHEET": "ODS",
    "APPLICATION/X-WIN-BITMAP": "BMP",
    "APPLICATION/X-WINZIP": "ZIP",
    "APPLICATION/X-WMF": "WMF",
    "APPLICATION/X-XLS": "XLS",
    # "APPLICATION/X-XLS": "XLSX",
    "APPLICATION/X-ZIP": "ZIP",
    "APPLICATION/X-ZIP-COMPRESSED": "ZIP",
    "APPLICATION/XHTML+XML": "XHTML",
    "APPLICATION/XML": "XML",
    "APPLICATION/ZIP": "ZIP",
    "ARCGRID": "ArcGRID",
    "AU": "AU",
    "AUDIO/3GPP": "M4A",
    "AUDIO/3GPP2": "M4A",
    "AUDIO/AAC": "M4A",
    "AUDIO/AACP": "M4A",
    "AUDIO/AIFF": "AIFF",
    "AUDIO/BASIC": "AU",
    "AUDIO/MP3": "MP3",
    "AUDIO/MP4": "M4A",
    "AUDIO/MP4A-LATM": "M4A",
    "AUDIO/MPEG": "MP3",
    "AUDIO/MPEG3": "MP3",
    "AUDIO/MPEG4-GENERIC": "M4A",
    "AUDIO/MPG": "MP3",
    "AUDIO/OGG": "OGG",
    "AUDIO/VORBIS": "OGG",
    "AUDIO/WAV": "WAV",
    "AUDIO/WAVE": "WAV",
    "AUDIO/X-AIFF": "AIFF",
    "AUDIO/X-AU": "AU",
    "AUDIO/X-MP3": "MP3",
    "AUDIO/X-MPEG": "MP3",
    "AUDIO/X-MPEG3": "MP3",
    "AUDIO/X-MPEGAUDIO": "MP3",
    "AUDIO/X-MPG": "MP3",
    "AUDIO/X-ULAW": "AU",
    "AUDIO/X-WAV": "WAV",
    "AVI": "AVI",
    "Agilent": "AgilentMicroarray",
    "BASE64": "Base64",
    "BDF": "BDF",
    "BINARY": "Binary",
    "BIT": "Bit",
    "BMP": "BMP",
    "BSON": "BSON",
    "BYTE": "Byte",
    "BYU": "BYU",
    "BZ2": "BZIP2",
    "BZ2": "BZIP2",
    "BZIP": "BZIP2",
    "BZIP": "BZIP2",
    "BZIP2": "BZIP2",
    "C": "C",
    "CDED": "CDED",
    "CDF": "CDF",
    "CHARACTER16": "Character16",
    "CHARACTER8": "Character8",
    "CIF": "CIF",
    "COMPLEX128": "Complex128",
    "COMPLEX256": "Complex256",
    "COMPLEX64": "Complex64",
    "CSV": "CSV",
    "CUR": "CUR",
    "DAE": "DAE",
    "DBF": "DBF",
    "DICOM": "DICOM",
    "DIF": "DIF",
    "DIMACS": "DIMACS",
    "DIRECTORY": "Directory",
    "DOT": "DOT",
    "DXF": "DXF",
    "EDF": "EDF",
    "EMF": "EMF",
    "EML": "EML",
    "ENHANCEDMETAFILE": "EMF",
    "EPS": "EPS",
    "EXPRESSIONJSON": "ExpressionJSON",
    "EXPRESSIONML": "ExpressionML",
    "Excel": "XLS",
    "FASTA": "FASTA",
    "FASTQ": "FASTQ",
    "FCS": "FCS",
    "FITS": "FITS",
    "FLAC": "FLAC",
    "FLASH": "SWF",
    "FLV": "FLV",
    "FMU": "FMU",
    "Flash": "SWF",
    "GENBANK": "GenBank",
    "GEOJSON": "GeoJSON",
    "GEOTIFF": "GeoTIFF",
    "GIF": "GIF",
    "GPX": "GPX",
    "GRAPH6": "Graph6",
    "GRAPHLET": "Graphlet",
    "GRAPHML": "GraphML",
    "GRIB": "GRIB",
    "GTOPO30": "GTOPO30",
    "GXL": "GXL",
    "GZ": "GZIP",
    "GZIP": "GZIP",
    "GraphWin": "LEDA",
    "HARWELLBOEING": "HarwellBoeing",
    "HDF": "HDF",
    "HDF5": "HDF5",
    "HIN": "HIN",
    "HTML": "HTML",
    "HTMLFRAGMENT": "HTMLFragment",
    "HTMLMathML": "XHTMLMathML",
    "HTTPREQUEST": "HTTPRequest",
    "HTTPRESPONSE": "HTTPResponse",
    "ICC": "ICC",
    "ICNS": "ICNS",
    "ICO": "ICO",
    "ICS": "ICS",
    "IMAGE/BITMAP": "BMP",
    "IMAGE/BMP": "BMP",
    "IMAGE/DXF": "DXF",
    "IMAGE/EPS": "EPS",
    "IMAGE/FITS": "FITS",
    "IMAGE/GIF": "GIF",
    "IMAGE/JP2": "JPEG2000",
    "IMAGE/JPEG": "JPEG",
    "IMAGE/JPEG2000": "JPEG2000",
    "IMAGE/JPEG2000-IMAGE": "JPEG2000",
    "IMAGE/JPG": "JPEG",
    "IMAGE/MS-BMP": "BMP",
    "IMAGE/PCX": "PCX",
    "IMAGE/PICT": "PICT",
    "IMAGE/PJPEG": "JPEG",
    "IMAGE/PNG": "PNG",
    "IMAGE/SVG+XML": "SVG",
    "IMAGE/SVG-XML": "SVG",
    "IMAGE/TARGA": "TGA",
    "IMAGE/TGA": "TGA",
    "IMAGE/TIF": "TIFF",
    "IMAGE/TIFF": "TIFF",
    "IMAGE/VND.DXF": "DXF",
    "IMAGE/VND.MICROSOFT.ICON": "ICO",
    "IMAGE/WMF": "WMF",
    "IMAGE/X-3DS": "3DS",
    "IMAGE/X-AUTOCAD": "DXF",
    "IMAGE/X-BITMAP": "BMP",
    "IMAGE/X-BMP": "BMP",
    "IMAGE/X-DXF": "DXF",
    "IMAGE/X-EMF": "EMF",
    "IMAGE/X-EPS": "EPS",
    "IMAGE/X-EXR": "OpenEXR",
    "IMAGE/X-JPEG2000-IMAGE": "JPEG2000",
    "IMAGE/X-MGX-EMF": "EMF",
    "IMAGE/X-MS-BMP": "BMP",
    "IMAGE/X-PBM": "PBM",
    "IMAGE/X-PC-PAINTBRUCH": "PCX",
    "IMAGE/X-PCX": "PCX",
    "IMAGE/X-PGM": "PGM",
    "IMAGE/X-PICT": "PICT",
    "IMAGE/X-PNG": "PNG",
    "IMAGE/X-PNM": "PNM",
    "IMAGE/X-PORTABLE-ANYMAP": "PNM",
    "IMAGE/X-PORTABLE-BITMAP": "PBM",
    "IMAGE/X-PORTABLE-GRAYMAP": "PGM",
    "IMAGE/X-PORTABLE-PIXMAP": "PPM",
    "IMAGE/X-PPM": "PPM",
    "IMAGE/X-TARGA": "TGA",
    "IMAGE/X-TGA": "TGA",
    "IMAGE/X-TIF": "TIFF",
    "IMAGE/X-TIFF": "TIFF",
    "IMAGE/X-WIN-BITMAP": "BMP",
    "IMAGE/X-WIN-METAFILE": "WMF",
    "IMAGE/X-WINDOWS-BITMAP": "BMP",
    "IMAGE/X-WMF": "WMF",
    "IMAGE/X-XBITMAP": "EMF",
    # "IMAGE/X-XBITMAP": "XBM",
    "IMAGE/X-XBM": "XBM",
    "IMAGE/XBM": "XBM",
    "INI": "Ini",
    "INTEGER128": "Integer128",
    "INTEGER16": "Integer16",
    "INTEGER24": "Integer24",
    "INTEGER32": "Integer32",
    "INTEGER64": "Integer64",
    "INTEGER8": "Integer8",
    "JAR": "ZIP",
    "JAVAPROPERTIES": "JavaProperties",
    "JAVASCRIPTEXPRESSION": "JavaScriptExpression",
    "JCAMP-DX": "JCAMP-DX",
    "JCAMPDX": "JCAMP-DX",
    "JPEG": "JPEG",
    "JPEG2000": "JPEG2000",
    "JPG": "JPEG",
    "JSON": "JSON",
    "JVX": "JVX",
    "KML": "KML",
    "LATEX": "LaTeX",
    "LEDA": "LEDA",
    "LIST": "List",
    "LWO": "LWO",
    "M4A": "M4A",
    "MAT": "MAT",
    "MATHML": "MathML",
    "MAYA": "Maya",
    "MBOX": "MBOX",
    "MCTT": "MCTT",
    "MDB": "MDB",
    "MESH": "MESH",
    "MESSAGE/RFC822": "EML",
    "METAFILE": "WMF",
    "MGF": "MGF",
    "MIDI": "MIDI",
    "MMCIF": "MMCIF",
    "MO": "MO",
    "MODEL/X-POV": "POV",
    "MOL": "MOL",
    "MOL2": "MOL2",
    "MP3": "MP3",
    "MPS": "MPS",
    "MTP": "MTP",
    "MTX": "MTX",
    "MULTIPART/X-GZIP": "GZIP",
    "MULTIPART/X-TAR": "TAR",
    "MULTIPART/X-ZIP": "ZIP",
    "MX": "MX",
    "MXNET": "MXNet",
    "MatrixMarket": "MTX",
    "Metafile": "WMF",
    "MuLaw": "AU",
    "NASACDF": "NASACDF",
    "NB": "NB",
    "NDK": "NDK",
    "NETCDF": "NetCDF",
    "NEXUS": "NEXUS",
    "NOFF": "NOFF",
    "OBJ": "OBJ",
    "ODS": "ODS",
    "OFF": "OFF",
    "OGG": "OGG",
    "OPENEXR": "OpenEXR",
    "PACKAGE": "Package",
    "PAJEK": "Pajek",
    "PBM": "PBM",
    "PCAP": "PCAP",
    "PCX": "PCX",
    "PDB": "PDB",
    "PDF": "PDF",
    "PGM": "PGM",
    "PHPINI": "PHPIni",
    "PICT": "PICT",
    "PLY": "PLY",
    "PNG": "PNG",
    "PNM": "PNM",
    "POV": "POV",
    "PPM": "PPM",
    "PXR": "PXR",
    "PYTHONEXPRESSION": "PythonExpression",
    "QUICKTIME": "QuickTime",
    "RAW": "Raw",
    "RAW": "Raw",
    "RAWBITMAP": "RawBitmap",
    "RAWJSON": "RawJSON",
    "REAL128": "Real128",
    "REAL32": "Real32",
    "REAL64": "Real64",
    "RIB": "RIB",
    "RICHTEXT": "RTF",
    "RLE": "RLE",
    "RSS": "RSS",
    "RTF": "RTF",
    "RichText": "RTF",
    "SCT": "SCT",
    "SDF": "SDF",
    "SDTS": "SDTS",
    "SDTSDEM": "SDTSDEM",
    "SFF": "SFF",
    "SHP": "SHP",
    "SMA": "SMA",
    "SME": "SME",
    "SMILES": "SMILES",
    "SND": "SND",
    "SP3": "SP3",
    "SPARSE6": "Sparse6",
    "STL": "STL",
    "STRING": "String",
    "SURFERGRID": "SurferGrid",
    "SVG": "SVG",
    "SWF": "SWF",
    "SXC": "SXC",
    "TABLE": "Table",
    "TAR": "TAR",
    "TERMINATEDSTRING": "TerminatedString",
    "TEX": "TeX",
    "TEXFRAGMENT": "TeXFragment",
    "TEXT": "Text",
    "TEXT/CALENDAR": "ICS",
    # "TEXT/CALENDAR": "VCS",
    "TEXT/COMMA-SEPARATED-VALUES": "CSV",
    "TEXT/CSV": "CSV",
    "TEXT/HTML": "HTML",
    "TEXT/PDF": "PDF",
    "TEXT/PLAIN": "Text",
    "TEXT/RICHTEXT": "RTF",
    "TEXT/RTF": "RTF",
    "TEXT/TAB-SEPARATED-VALUES": "TSV",
    "TEXT/X-COMMA-SEPARATED-VALUES": "CSV",
    "TEXT/X-PDF": "PDF",
    "TEXT/X-VCARD": "VCF",
    "TEXT/XML": "XML",
    "TGA": "TGA",
    "TGF": "TGF",
    "TGZ": "GZIP",
    "TIFF": "TIFF",
    "TIGER": "TIGER",
    "TLE": "TLE",
    "TSV": "TSV",
    "UBJSON": "UBJSON",
    "UNSIGNEDINTEGER128": "UnsignedInteger128",
    "UNSIGNEDINTEGER16": "UnsignedInteger16",
    "UNSIGNEDINTEGER24": "UnsignedInteger24",
    "UNSIGNEDINTEGER32": "UnsignedInteger32",
    "UNSIGNEDINTEGER64": "UnsignedInteger64",
    "UNSIGNEDINTEGER8": "UnsignedInteger8",
    "USGSDEM": "USGSDEM",
    "UUE": "UUE",
    "VCARD": "VCF",
    "VCF": "VCF",
    "VCS": "VCS",
    "VIDEO/AVI": "AVI",
    "VIDEO/MSVIDEO": "AVI",
    "VIDEO/QUICKTIME": "QuickTime",
    "VIDEO/X-FLV": "FLV",
    "VIDEO/X-MATROSKA": "MKV",
    "VIDEO/X-MSVIDEO": "AVI",
    "VIDEOFRAMES": "VideoFrames",
    "VRML": "VRML",
    "VTK": "VTK",
    "WARC": "WARC",
    "WAV": "WAV",
    "WAVE": "WAV",
    "WAVE": "WAV",
    "WAVE64": "Wave64",
    "WDX": "WDX",
    "WEBP": "WebP",
    "WEBP": "WebP",
    "WINDOWS/METAFILE": "WMF",
    "WLNET": "WLNet",
    "WMF": "WMF",
    "WMLF": "WMLF",
    "WXF": "WXF",
    "X3D": "X3D",
    "XBITMAP": "XBM",
    "XBM": "XBM",
    "XHTML": "XHTML",
    "XHTMLMATHML": "XHTMLMathML",
    "XLS": "XLS",
    "XLSX": "XLSX",
    "XML": "XML",
    "XPORT": "XPORT",
    "XYZ": "XYZ",
    "ZIP": "ZIP",
    "ZPR": "ZPR",
    "ZZ-APPLICATION/ZZ-WINASSOC-DXF": "DXF",
    "ZZ-APPLICATION/ZZ-WINASSOC-PCX": "PCX",
    "ZZ-APPLICATION/ZZ-WINASSOC-WMF": "WMF",
    # "ZZ-APPLICATION/ZZ-WINASSOC-XLS": "XLS",
    # "ZZ-APPLICATION/ZZ-WINASSOC-XLS": "XLSX",
    "vCard": "VCF",
}


def _importer_exporter_options(
    available_options, options, builtin_name: str, evaluation
):
    stream_options = []
    custom_options = []
    remaining_options = options.copy()

    if available_options and available_options.has_form("List", None):
        for name in available_options.leaves:
            if isinstance(name, String):
                py_name = name.get_string_value()
            elif isinstance(name, Symbol):
                py_name = strip_context(name.get_name())
            else:
                py_name = None

            if py_name:
                value = get_option(remaining_options, py_name, evaluation, pop=True)
                if value is not None:
                    expr = Expression(SymbolRule, String(py_name), value)
                    if py_name == "CharacterEncoding":
                        stream_options.append(expr)
                    else:
                        custom_options.append(expr)

    syntax_option = remaining_options.get("System`$OptionSyntax", None)
    if syntax_option and syntax_option != Symbol("System`Ignore"):
        # warn about unsupported options.
        for name, value in remaining_options.items():
            evaluation.message(
                builtin_name,
                "optx",
                Expression(SymbolRule, strip_context(name), value),
                strip_context(builtin_name),
            )

    return stream_options, custom_options


class ImportFormats(Predefined):
    """
    <dl>
    <dt>'$ImportFormats'
        <dd>returns a list of file formats supported by Import.
    </dl>

    >> $ImportFormats
     = {...CSV,...JSON,...Text...}
    """

    name = "$ImportFormats"

    def evaluate(self, evaluation):
        return Expression(SymbolList, *sorted(IMPORTERS.keys()))


class ExportFormats(Predefined):
    """
    <dl>
    <dt>'$ExportFormats'
        <dd>returns a list of file formats supported by Export.
    </dl>

    >> $ExportFormats
     = {...CSV,...SVG,...Text...}
    """

    name = "$ExportFormats"

    def evaluate(self, evaluation):
        return Expression(SymbolList, *sorted(EXPORTERS.keys()))


class ConverterDumpsExtensionMappings(Predefined):
    """
    <dl>
    <dt>'$extensionMappings'
        <dd>Returns a list of associations between file extensions and file types.
    </dl>
    """

    context = "System`ConvertersDump`"
    name = "$extensionMappings"
    attributes = ["Unprotected"]

    def evaluate(self, evaluation):
        return from_python(EXTENSIONMAPPINGS)


class ConverterDumpsFormatMappings(Predefined):
    """
    <dl>
    <dt>'$formatMappings'
        <dd>Returns a list of associations between file extensions and file types.
    </dl>
    """

    context = "System`ConvertersDump`"
    name = "$formatMappings"
    attributes = ["Unprotected"]

    def evaluate(self, evaluation):
        return from_python(FORMATMAPPINGS)


class RegisterImport(Builtin):
    """
    <dl>
    <dt>'RegisterImport["$format$", $defaultFunction$]'
      <dd>register '$defaultFunction$' as the default function used when importing from a file of type '"$format$"'.
    <dt>'RegisterImport["$format$", {"$elem1$" :> $conditionalFunction1$, "$elem2$" :> $conditionalFunction2$, ..., $defaultFunction$}]'
      <dd>registers multiple elements ($elem1$, ...) and their corresponding converter functions ($conditionalFunction1$, ...) in addition to the $defaultFunction$.
    <dt>'RegisterImport["$format$", {"$conditionalFunctions$, $defaultFunction$, "$elem3$" :> $postFunction3$, "$elem4$" :> $postFunction4$, ...}]'
      <dd>also registers additional elements ($elem3$, ...) whose converters ($postFunction3$, ...) act on output from the low-level funcions.
    </dl>

    First, define the default function used to import the data.
    >> ExampleFormat1Import[filename_String] := Module[{stream, head, data}, stream = OpenRead[filename]; head = ReadList[stream, String, 2]; data = Partition[ReadList[stream, Number], 2]; Close[stream]; {"Header" -> head, "Data" -> data}]

    'RegisterImport' is then used to register the above function to a new data format.
    >> ImportExport`RegisterImport["ExampleFormat1", ExampleFormat1Import]

    >> FilePrint["ExampleData/ExampleData.txt"]
     | Example File Format
     | Created by Angus
     | 0.629452	0.586355
     | 0.711009	0.687453
     | 0.246540	0.433973
     | 0.926871	0.887255
     | 0.825141	0.940900
     | 0.847035	0.127464
     | 0.054348	0.296494
     | 0.838545	0.247025
     | 0.838697	0.436220
     | 0.309496	0.833591

    >> Import["ExampleData/ExampleData.txt", {"ExampleFormat1", "Elements"}]
     = {Data, Header}

    >> Import["ExampleData/ExampleData.txt", {"ExampleFormat1", "Header"}]
     = {Example File Format, Created by Angus}

    Conditional Importer:
    >> ExampleFormat2DefaultImport[filename_String] := Module[{stream, head}, stream = OpenRead[filename]; head = ReadList[stream, String, 2]; Close[stream]; {"Header" -> head}]

    >> ExampleFormat2DataImport[filename_String] := Module[{stream, data}, stream = OpenRead[filename]; Skip[stream, String, 2]; data = Partition[ReadList[stream, Number], 2]; Close[stream]; {"Data" -> data}]

    >> ImportExport`RegisterImport["ExampleFormat2", {"Data" :> ExampleFormat2DataImport, ExampleFormat2DefaultImport}]

    >> Import["ExampleData/ExampleData.txt", {"ExampleFormat2", "Elements"}]
     = {Data, Header}

    >> Import["ExampleData/ExampleData.txt", {"ExampleFormat2", "Header"}]
     = {Example File Format, Created by Angus}

    >> Import["ExampleData/ExampleData.txt", {"ExampleFormat2", "Data"}] // Grid
     = 0.629452   0.586355
     .
     . 0.711009   0.687453
     .
     . 0.24654    0.433973
     .
     . 0.926871   0.887255
     .
     . 0.825141   0.9409
     .
     . 0.847035   0.127464
     .
     . 0.054348   0.296494
     .
     . 0.838545   0.247025
     .
     . 0.838697   0.43622
     .
     . 0.309496   0.833591

    """

    context = "ImportExport`"

    attributes = ("Protected", "ReadProtected")

    # XXX OptionsIssue
    options = {
        "Path": "Automatic",
        "FunctionChannels": '{"FileNames"}',
        "Sources": "None",
        "DefaultElement": "Automatic",
        "AvailableElements": "None",
        "Options": "{}",
        "OriginalChannel": "False",
        "BinaryFormat": "False",
        "Encoding": "False",
        "Extensions": "{}",
        "AlphaChannel": "False",
    }

    rules = {
        "ImportExport`RegisterImport[formatname_String, function_]": "ImportExport`RegisterImport[formatname, function, {}]",
    }

    def apply(self, formatname, function, posts, evaluation, options):
        """ImportExport`RegisterImport[formatname_String, function_, posts_,
        OptionsPattern[ImportExport`RegisterImport]]"""

        if function.has_form("List", None):
            leaves = function.get_leaves()
        else:
            leaves = [function]

        if not (
            len(leaves) >= 1
            and isinstance(leaves[-1], Symbol)
            and all(x.has_form("RuleDelayed", None) for x in leaves[:-1])
        ):
            # TODO: Message
            return SymbolFailed

        conditionals = {
            elem.get_string_value(): expr
            for (elem, expr) in (x.get_leaves() for x in leaves[:-1])
        }
        default = leaves[-1]
        posts = {}

        IMPORTERS[formatname.get_string_value()] = (
            conditionals,
            default,
            posts,
            options,
        )

        return Symbol("Null")


class RegisterExport(Builtin):
    """
    <dl>
    <dt>'RegisterExport["$format$", $func$]'
      <dd>register '$func$' as the default function used when exporting from a file of type '"$format$"'.
    </dl>

    Simple text exporter
    >> ExampleExporter1[filename_, data_, opts___] := Module[{strm = OpenWrite[filename], char = data}, WriteString[strm, char]; Close[strm]]

    >> ImportExport`RegisterExport["ExampleFormat1", ExampleExporter1]

    >> Export["sample.txt", "Encode this string!", "ExampleFormat1"];

    >> FilePrint["sample.txt"]
     | Encode this string!

    #> DeleteFile["sample.txt"]

    Very basic encrypted text exporter
    >> ExampleExporter2[filename_, data_, opts___] := Module[{strm = OpenWrite[filename], char}, (* TODO: Check data *) char = FromCharacterCode[Mod[ToCharacterCode[data] - 84, 26] + 97]; WriteString[strm, char]; Close[strm]]

    >> ImportExport`RegisterExport["ExampleFormat2", ExampleExporter2]

    >> Export["sample.txt", "encodethisstring", "ExampleFormat2"];

    >> FilePrint["sample.txt"]
     | rapbqrguvffgevat

    #> DeleteFile["sample.txt"]
    """

    context = "ImportExport`"

    options = {
        "Path": "Automatic",
        "FunctionChannels": '{"FileNames"}',
        "Sources": "None",
        "DefaultElement": "None",
        "AvailableElements": "None",
        "Options": "{}",
        "OriginalChannel": "False",
        "BinaryFormat": "False",
        "Encoding": "False",
        "Extensions": "{}",
        "AlphaChannel": "False",
    }

    def apply(self, formatname, function, evaluation, options):
        """ImportExport`RegisterExport[formatname_String, function_,
        OptionsPattern[ImportExport`RegisterExport]]"""
        EXPORTERS[formatname.get_string_value()] = (function, options)

        return Symbol("Null")


class URLFetch(Builtin):
    """
    <dl>
    <dt>'URLFetch[$URL$]'
      <dd> Returns the content of $URL$ as a string.
    </dl>


    #> Quiet[URLFetch["https:////", {}]]
     = $Failed

    ##> Quiet[URLFetch["https://www.example.com", {}]]
    # = ...
    """

    messages = {
        "httperr": "`1` could not be retrieved; `2`.",
    }

    def apply(self, url, elements, evaluation, options={}):
        "URLFetch[url_String, elements_, OptionsPattern[]]"

        import tempfile
        import os

        py_url = url.get_string_value()

        temp_handle, temp_path = tempfile.mkstemp(suffix="")
        try:
            # some pages need cookies or they will end up in an infinite redirect (i.e. HTTP 303)
            # loop, which prevents the page from getting loaded.
            f = urllib2.build_opener(urllib2.HTTPCookieProcessor).open(py_url)

            try:
                if sys.version_info >= (3, 0):
                    content_type = f.info().get_content_type()
                else:
                    content_type = f.headers["content-type"]

                os.write(temp_handle, f.read())
            finally:
                f.close()

                # on some OS (e.g. Windows) all writers need to be closed before another
                # reader (e.g. Import._import) can access it. so close the file here.
                os.close(temp_handle)

            def determine_filetype():
                return mimetype_dict.get(content_type)

            result = Import._import(
                temp_path, determine_filetype, elements, evaluation, options
            )
        except HTTPError as e:
            evaluation.message(
                "URLFetch",
                "httperr",
                url,
                "the server returned an HTTP status code of %s (%s)"
                % (e.code, str(e.reason)),
            )
            return SymbolFailed
        except URLError as e:  # see https://docs.python.org/3/howto/urllib2.html
            if hasattr(e, "reason"):
                evaluation.message("URLFetch", "httperr", url, str(e.reason))
            elif hasattr(e, "code"):
                evaluation.message(
                    "URLFetch", "httperr", url, "server returned %s" % e.code
                )
            return SymbolFailed
        except ValueError as e:
            evaluation.message("URLFetch", "httperr", url, str(e))
            return SymbolFailed
        finally:
            try:
                os.close(temp_handle)
            except OSError:
                pass
            os.unlink(temp_path)

        return result


class Import(Builtin):
    """
    <dl>
    <dt>'Import["$file$"]'
      <dd>imports data from a file.
    <dt>'Import["$file$", $elements$]'
      <dd>imports the specified elements from a file.
    <dt>'Import["http://$url$", ...]' and 'Import["ftp://$url$", ...]'
      <dd>imports from a URL.
    </dl>

    #> Import["ExampleData/ExampleData.tx"]
     : File not found during Import.
     = $Failed
    #> Import[x]
     : First argument x is not a valid file, directory, or URL specification.
     = $Failed

    ## CSV
    #> Import["ExampleData/numberdata.csv", "Elements"]
     = {Data, Grid}
    #> Import["ExampleData/numberdata.csv", "Data"]
    = {{0.88, 0.60, 0.94}, {0.76, 0.19, 0.51}, {0.97, 0.04, 0.26}, {0.33, 0.74, 0.79}, {0.42, 0.64, 0.56}}
    #> Import["ExampleData/numberdata.csv"]
    = {{0.88, 0.60, 0.94}, {0.76, 0.19, 0.51}, {0.97, 0.04, 0.26}, {0.33, 0.74, 0.79}, {0.42, 0.64, 0.56}}
    #> Import["ExampleData/numberdata.csv", "FieldSeparators" -> "."]
    = {{0, 88,0, 60,0, 94}, {0, 76,0, 19,0, 51}, {0, 97,0, 04,0, 26}, {0, 33,0, 74,0, 79}, {0, 42,0, 64,0, 56}}

    ## Text
    >> Import["ExampleData/ExampleData.txt", "Elements"]
     = {Data, Lines, Plaintext, String, Words}
    >> Import["ExampleData/ExampleData.txt", "Lines"]
     = ...
    #> Import["ExampleData/Middlemarch.txt"];
     : An invalid unicode sequence was encountered and ignored.

    ## JSON
    >> Import["ExampleData/colors.json"]
     = {colorsArray -> {{colorName -> black, rgbValue -> (0, 0, 0), hexValue -> #000000}, {colorName -> red, rgbValue -> (255, 0, 0), hexValue -> #FF0000}, {colorName -> green, rgbValue -> (0, 255, 0), hexValue -> #00FF00}, {colorName -> blue, rgbValue -> (0, 0, 255), hexValue -> #0000FF}, {colorName -> yellow, rgbValue -> (255, 255, 0), hexValue -> #FFFF00}, {colorName -> cyan, rgbValue -> (0, 255, 255), hexValue -> #00FFFF}, {colorName -> magenta, rgbValue -> (255, 0, 255), hexValue -> #FF00FF}, {colorName -> white, rgbValue -> (255, 255, 255), hexValue -> #FFFFFF}}}

    ## XML
    #> Import["ExampleData/InventionNo1.xml", "Tags"]
     = {accidental, alter, arpeggiate, ..., words}
    """

    messages = {
        "nffil": "File not found during Import.",
        "chtype": (
            "First argument `1` is not a valid file, directory, "
            "or URL specification."
        ),
        "noelem": ("The Import element `1` is not present when importing as `2`."),
        "fmtnosup": "`1` is not a supported Import format.",
        "emptyfch": "Function Channel not defined.",
    }

    rules = {
        "Import[filename_]": "Import[filename, {}]",
    }

    options = {
        "$OptionSyntax": "System`Ignore",
    }

    def apply(self, filename, evaluation, options={}):
        "Import[filename_, OptionsPattern[]]"
        return self.apply_elements(
            filename, Expression(SymbolList), evaluation, options
        )

    def apply_element(self, filename, element, evaluation, options={}):
        "Import[filename_, element_String, OptionsPattern[]]"
        return self.apply_elements(
            filename, Expression(SymbolList, element), evaluation, options
        )

    def apply_elements(self, filename, elements, evaluation, options={}):
        "Import[filename_, elements_List?(AllTrue[#, NotOptionQ]&), OptionsPattern[]]"
        # Check filename
        path = filename.to_python()
        if not (isinstance(path, str) and path[0] == path[-1] == '"'):
            evaluation.message("Import", "chtype", filename)
            return SymbolFailed

        # Load local file
        findfile = Expression("FindFile", filename).evaluate(evaluation)

        if findfile == SymbolFailed:
            evaluation.message("Import", "nffil")
            return findfile

        def determine_filetype():
            return (
                Expression("FileFormat", findfile)
                .evaluate(evaluation=evaluation)
                .get_string_value()
            )

        return self._import(findfile, determine_filetype, elements, evaluation, options)

    @staticmethod
    def _import(findfile, determine_filetype, elements, evaluation, options, data=None):
        current_predetermined_out = evaluation.predetermined_out
        # Check elements
        if elements.has_form("List", None):
            elements = elements.get_leaves()
        else:
            elements = [elements]

        for el in elements:
            if not isinstance(el, String):

                evaluation.message("Import", "noelem", el)
                evaluation.predetermined_out = current_predetermined_out
                return SymbolFailed

        elements = [el.get_string_value() for el in elements]

        # Determine file type
        for el in elements:
            if el in IMPORTERS.keys():
                filetype = el
                elements.remove(el)
                break
        else:
            filetype = determine_filetype()

        if filetype not in IMPORTERS.keys():
            evaluation.message("Import", "fmtnosup", filetype)
            evaluation.predetermined_out = current_predetermined_out
            return SymbolFailed

        # Load the importer
        (conditionals, default_function, posts, importer_options) = IMPORTERS[filetype]

        stream_options, custom_options = _importer_exporter_options(
            importer_options.get("System`Options"), options, "System`Import", evaluation
        )

        function_channels = importer_options.get("System`FunctionChannels")

        if function_channels is None:
            # TODO message
            if data is None:
                evaluation.message("Import", "emptyfch")
            else:
                evaluation.message("ImportString", "emptyfch")
            evaluation.predetermined_out = current_predetermined_out
            return SymbolFailed

        default_element = importer_options.get("System`DefaultElement")
        if default_element is None:
            # TODO message
            evaluation.predetermined_out = current_predetermined_out
            return SymbolFailed

        def get_results(tmp_function, findfile):
            if function_channels == Expression(SymbolList, String("FileNames")):
                joined_options = list(chain(stream_options, custom_options))
                tmpfile = False
                if findfile is None:
                    tmpfile = True
                    stream = Expression("OpenWrite").evaluate(evaluation)
                    findfile = stream.leaves[0]
                    if not data is None:
                        Expression("WriteString", data).evaluate(evaluation)
                    else:
                        Expression("WriteString", String("")).evaluate(evaluation)
                    Expression("Close", stream).evaluate(evaluation)
                    stream = None
                tmp = Expression(tmp_function, findfile, *joined_options).evaluate(
                    evaluation
                )
                if tmpfile:
                    Expression("DeleteFile", findfile).evaluate(evaluation)
            elif function_channels == Expression(SymbolList, String("Streams")):
                if findfile is None:
                    stream = Expression("StringToStream", data).evaluate(evaluation)
                else:
                    stream = Expression("OpenRead", findfile, *stream_options).evaluate(
                        evaluation
                    )
                if stream.get_head_name() != "System`InputStream":
                    evaluation.message("Import", "nffil")
                    evaluation.predetermined_out = current_predetermined_out
                    return None
                tmp = Expression(tmp_function, stream, *custom_options).evaluate(
                    evaluation
                )
                Expression("Close", stream).evaluate(evaluation)
            else:
                # TODO message
                evaluation.predetermined_out = current_predetermined_out
                return SymbolFailed
            tmp = tmp.get_leaves()
            if not all(expr.has_form("Rule", None) for expr in tmp):
                evaluation.predetermined_out = current_predetermined_out
                return None

            # return {a.get_string_value() : b for (a,b) in map(lambda x:
            # x.get_leaves(), tmp)}
            evaluation.predetermined_out = current_predetermined_out
            return dict(
                (a.get_string_value(), b) for (a, b) in [x.get_leaves() for x in tmp]
            )

        # Perform the import
        defaults = None

        if not elements:
            defaults = get_results(default_function, findfile)
            if defaults is None:
                evaluation.predetermined_out = current_predetermined_out
                return SymbolFailed
            if default_element == Symbol("Automatic"):
                evaluation.predetermined_out = current_predetermined_out
                return Expression(
                    "List",
                    *(
                        Expression(SymbolRule, String(key), defaults[key])
                        for key in defaults.keys()
                    )
                )
            else:
                result = defaults.get(default_element.get_string_value())
                if result is None:
                    evaluation.message(
                        "Import", "noelem", default_element, from_python(filetype)
                    )
                    evaluation.predetermined_out = current_predetermined_out
                    return SymbolFailed
                evaluation.predetermined_out = current_predetermined_out
                return result
        else:
            assert len(elements) == 1
            el = elements[0]
            if el == "Elements":
                defaults = get_results(default_function, findfile)
                if defaults is None:
                    evaluation.predetermined_out = current_predetermined_out
                    return SymbolFailed
                # Use set() to remove duplicates
                evaluation.predetermined_out = current_predetermined_out
                return from_python(
                    sorted(
                        set(
                            list(conditionals.keys())
                            + list(defaults.keys())
                            + list(posts.keys())
                        )
                    )
                )
            else:
                if el in conditionals.keys():
                    result = get_results(conditionals[el], findfile)
                    if result is None:
                        evaluation.predetermined_out = current_predetermined_out
                        return SymbolFailed
                    if len(list(result.keys())) == 1 and list(result.keys())[0] == el:
                        evaluation.predetermined_out = current_predetermined_out
                        return list(result.values())[0]
                elif el in posts.keys():
                    # TODO: allow use of conditionals
                    result = get_results(posts[el])
                    if result is None:
                        evaluation.predetermined_out = current_predetermined_out
                        return SymbolFailed
                else:
                    if defaults is None:
                        defaults = get_results(default_function, findfile)
                        if defaults is None:
                            evaluation.predetermined_out = current_predetermined_out
                            return SymbolFailed
                    if el in defaults.keys():
                        evaluation.predetermined_out = current_predetermined_out
                        return defaults[el]
                    else:
                        evaluation.message(
                            "Import", "noelem", from_python(el), from_python(filetype)
                        )
                        evaluation.predetermined_out = current_predetermined_out
                        return SymbolFailed


class ImportString(Import):
    """
    <dl>
    <dt>'ImportString["$data$", "$format$"]'
      <dd>imports data in the specified format from a string.
    <dt>'ImportString["$file$", $elements$]'
      <dd>imports the specified elements from a string.
    <dt>'ImportString["$data$"]'
      <dd>attempts to determine the format of the string from its content.
    </dl>


    #> ImportString[x]
     : First argument x is not a string.
     = $Failed

    ## CSV
    #> datastring = "0.88, 0.60, 0.94\\n.076, 0.19, .51\\n0.97, 0.04, .26";
    #> ImportString[datastring, "Elements"]
     = {Data, Lines, Plaintext, String, Words}
    #> ImportString[datastring, {"CSV","Elements"}]
     = {Data, Grid}
    #> ImportString[datastring, {"CSV", "Data"}]
    = {{0.88,  0.60,  0.94}, {.076,  0.19,  .51}, {0.97,  0.04,  .26}}
    #> ImportString[datastring]
    = 0.88, 0.60, 0.94
    .  .076, 0.19, .51
    .  0.97, 0.04, .26
    #> ImportString[datastring, "CSV","FieldSeparators" -> "."]
    = {{0, 88, 0, 60, 0, 94}, {076, 0, 19, , 51}, {0, 97, 0, 04, , 26}}

    ## Text
    >> str = "Hello!\\n    This is a testing text\\n";
    >> ImportString[str, "Elements"]
     = {Data, Lines, Plaintext, String, Words}
    >> ImportString[str, "Lines"]
     = ...
    """

    messages = {
        "string": "First argument `1` is not a string.",
        "noelem": ("The Import element `1` is not present when importing as `2`."),
        "fmtnosup": "`1` is not a supported Import format.",
    }

    rules = {}

    options = {
        "$OptionSyntax": "System`Ignore",
    }

    def apply(self, data, evaluation, options={}):
        "ImportString[data_, OptionsPattern[]]"
        return self.apply_elements(data, Expression(SymbolList), evaluation, options)

    def apply_element(self, data, element, evaluation, options={}):
        "ImportString[data_, element_String, OptionsPattern[]]"

        return self.apply_elements(
            data, Expression(SymbolList, element), evaluation, options
        )

    def apply_elements(self, data, elements, evaluation, options={}):
        "ImportString[data_, elements_List?(AllTrue[#, NotOptionQ]&), OptionsPattern[]]"
        if not (isinstance(data, String)):
            evaluation.message("ImportString", "string", data)
            return SymbolFailed
        path = data.get_string_value()

        def determine_filetype():
            if not FileFormat.detector:
                loader = magic.MagicLoader()
                loader.load()
                FileFormat.detector = magic.MagicDetector(loader.mimetypes)
            mime = set(FileFormat.detector.match("", data=data.to_python()))

            result = []
            for key in mimetype_dict.keys():
                if key in mime:
                    result.append(mimetype_dict[key])

            # the following fixes an extremely annoying behaviour on some (not all)
            # installations of Windows, where we end up classifying .csv files als XLS.
            if (
                len(result) == 1
                and result[0] == "XLS"
                and path.lower().endswith(".csv")
            ):
                return String("CSV")

            if len(result) == 0:
                result = "Binary"
            elif len(result) == 1:
                result = result[0]
            else:
                return None

            return result

        return self._import(
            None, determine_filetype, elements, evaluation, options, data=data
        )


class Export(Builtin):
    """
    <dl>
    <dt>'Export["$file$.$ext$", $expr$]'
      <dd>exports $expr$ to a file, using the extension $ext$ to determine the format.
    <dt>'Export["$file$", $expr$, "$format$"]'
      <dd>exports $expr$ to a file in the specified format.
    <dt>'Export["$file$", $exprs$, $elems$]'
      <dd>exports $exprs$ to a file as elements specified by $elems$.
    </dl>

    ## Invalid Filename
    #> Export["abc.", 1+2]
     : Cannot infer format of file abc..
     = $Failed
    #> Export[".ext", 1+2]
     : Cannot infer format of file .ext.
     = $Failed
    #> Export[x, 1+2]
     : First argument x is not a valid file specification.
     = $Failed

    ## Explicit Format
    #> Export["abc.txt", 1+x, "JPF"]
     : {JPF} is not a valid set of export elements for the Text format.
     = $Failed
    #> Export["abc.txt", 1+x, {"JPF"}]
     : {JPF} is not a valid set of export elements for the Text format.
     = $Failed

    ## Empty elems
    #> Export["123.txt", 1+x, {}]
     = 123.txt
    #> Export["123.jcp", 1+x, {}]
     : Cannot infer format of file 123.jcp.
     = $Failed

    ## Compression
    ## #> Export["abc.txt", 1+x, "ZIP"]    (* MMA Bug - Export::type *)
    ##  : {ZIP} is not a valid set of export elements for the Text format.
    ##  = $Failed
    ## #> Export["abc.txt", 1+x, "BZIP"]   (* MMA Bug - General::stop *)
    ##  : {BZIP} is not a valid set of export elements for the Text format.
    ##  = $Failed
    ## #> Export["abc.txt", 1+x, {"BZIP", "ZIP", "Text"}]
    ##  = abc.txt
    ## #> Export["abc.txt", 1+x, {"GZIP", "Text"}]
    ##  = abc.txt
    ## #> Export["abc.txt", 1+x, {"BZIP2", "Text"}]
    ##  = abc.txt

    ## FORMATS

    """

    messages = {
        "chtype": "First argument `1` is not a valid file specification.",
        "infer": "Cannot infer format of file `1`.",
        "noelem": "`1` is not a valid set of export elements for the `2` format.",
        "emptyfch": "Function Channel not defined.",
        "nffil": "File `1` could not be opened",
    }

    _extdict = {
        "bmp": "BMP",
        "gif": "GIF",
        "jp2": "JPEG2000",
        "jpg": "JPEG",
        "pcx": "PCX",
        "png": "PNG",
        "ppm": "PPM",
        "pbm": "PBM",
        "pgm": "PGM",
        "tif": "TIFF",
        "txt": "Text",
        "csv": "CSV",
        "svg": "SVG",
    }

    rules = {
        "Export[filename_, expr_, elems_?NotListQ]": (
            "Export[filename, expr, {elems}]"
        ),
    }

    options = {
        "$OptionSyntax": "System`Ignore",
    }

    def apply(self, filename, expr, evaluation, **options):
        "Export[filename_, expr_, OptionsPattern[Export]]"

        # Check filename
        if not self._check_filename(filename, evaluation):
            return SymbolFailed

        # Determine Format
        form = self._infer_form(filename, evaluation)

        if form is None:
            evaluation.message("Export", "infer", filename)
            return SymbolFailed
        else:
            return self.apply_elements(
                filename, expr, String(form), evaluation, options
            )

    def apply_element(self, filename, expr, element, evaluation, options={}):
        "Export[filename_, expr_, element_String, OptionsPattern[]]"
        return self.apply_elements(
            filename, expr, Expression(SymbolList, element), evaluation, options
        )

    def apply_elements(self, filename, expr, elems, evaluation, options={}):
        "Export[filename_, expr_, elems_List?(AllTrue[#, NotOptionQ]&), OptionsPattern[]]"

        # Check filename
        if not self._check_filename(filename, evaluation):
            return SymbolFailed

        # Process elems {comp* format?, elem1*}
        leaves = elems.get_leaves()

        format_spec, elems_spec = [], []
        found_form = False
        for leaf in leaves[::-1]:
            leaf_str = leaf.get_string_value()

            if not found_form and leaf_str in EXPORTERS:
                found_form = True

            if found_form:
                format_spec.append(leaf_str)
            else:
                elems_spec.append(leaf)

        # Just to be sure that the following calls do not change the state of this property
        current_predetermined_out = evaluation.predetermined_out
        # Infer format if not present
        if not found_form:
            assert format_spec == []
            format_spec = self._infer_form(filename, evaluation)
            if format_spec is None:
                evaluation.message("Export", "infer", filename)
                evaluation.predetermined_out = current_predetermined_out
                return SymbolFailed
            format_spec = [format_spec]
        else:
            assert format_spec != []

        # First item in format_spec is the explicit format.
        # The other elements (if present) are compression formats

        if elems_spec != []:  # FIXME: support elems
            evaluation.message("Export", "noelem", elems, String(format_spec[0]))
            evaluation.predetermined_out = current_predetermined_out
            return SymbolFailed

        # Load the exporter
        exporter_symbol, exporter_options = EXPORTERS[format_spec[0]]
        function_channels = exporter_options.get("System`FunctionChannels")
        stream_options, custom_options = _importer_exporter_options(
            exporter_options.get("System`Options"), options, "System`Export", evaluation
        )

        if function_channels is None:
            evaluation.message("Export", "emptyfch")
            evaluation.predetermined_out = current_predetermined_out
            return SymbolFailed
        elif function_channels == Expression(SymbolList, String("FileNames")):
            exporter_function = Expression(
                exporter_symbol,
                filename,
                expr,
                *list(chain(stream_options, custom_options))
            )
            res = exporter_function.evaluate(evaluation)
        elif function_channels == Expression(SymbolList, String("Streams")):
            stream = Expression("OpenWrite", filename, *stream_options).evaluate(
                evaluation
            )
            if stream.get_head_name() != "System`OutputStream":
                evaluation.message("Export", "nffil")
                evaluation.predetermined_out = current_predetermined_out
                return Symbol("$Failed")
            exporter_function = Expression(
                exporter_symbol,
                stream,
                expr,
                *list(chain(stream_options, custom_options))
            )
            res = exporter_function.evaluate(evaluation)
            Expression("Close", stream).evaluate(evaluation)
        if res == Symbol("Null"):
            evaluation.predetermined_out = current_predetermined_out
            return filename
        evaluation.predetermined_out = current_predetermined_out
        return SymbolFailed

    def _check_filename(self, filename, evaluation):
        path = filename.to_python()
        if isinstance(path, str) and path[0] == path[-1] == '"':
            return True
        evaluation.message("Export", "chtype", filename)
        return False

    def _infer_form(self, filename, evaluation):
        ext = Expression("FileExtension", filename).evaluate(evaluation)
        ext = ext.get_string_value().lower()
        return self._extdict.get(ext)


class ExportString(Builtin):
    """
    <dl>
    <dt>'ExportString[$expr$, $form$]'
      <dd>exports $expr$ to a string, in the format $form$.
    <dt>'Export["$file$", $exprs$, $elems$]'
      <dd>exports $exprs$ to a string as elements specified by $elems$.
    </dl>

    >> ExportString[{{1,2,3,4},{3},{2},{4}}, "CSV"]
     = 1,2,3,4
     . 3,
     . 2,
     . 4,

    >> ExportString[{1,2,3,4}, "CSV"]
     = 1,
     . 2,
     . 3,
     . 4,
    >> ExportString[Integrate[f[x],{x,0,2}], "SVG"]//Head
     = String
    """

    options = {
        "$OptionSyntax": "System`Ignore",
    }

    messages = {
        "noelem": "`1` is not a valid set of export elements for the `2` format.",
        "emptyfch": "Function Channel not defined.",
    }

    rules = {
        "ExportString[expr_, elems_?NotListQ]": ("ExportString[expr, {elems}]"),
    }

    def apply_element(self, expr, element, evaluation, **options):
        "ExportString[expr_, element_String, OptionsPattern[ExportString]]"
        return self.apply_elements(
            expr, Expression(SymbolList, element), evaluation, **options
        )

    def apply_elements(self, expr, elems, evaluation, **options):
        "ExportString[expr_, elems_List?(AllTrue[#, NotOptionQ]&), OptionsPattern[ExportString]]"
        # Process elems {comp* format?, elem1*}
        leaves = elems.get_leaves()
        format_spec, elems_spec = [], []
        found_form = False
        for leaf in leaves[::-1]:
            leaf_str = leaf.get_string_value()

            if not found_form and leaf_str in EXPORTERS:
                found_form = True

            if found_form:
                format_spec.append(leaf_str)
            else:
                elems_spec.append(leaf)

        # Just to be sure that the following evaluations do not change the value of this property
        current_predetermined_out = evaluation.predetermined_out

        # Infer format if not present
        if format_spec is None:
            # evaluation.message("ExportString", "infer", filename)
            evaluation.predetermined_out = current_predetermined_out
            return SymbolFailed

        # First item in format_spec is the explicit format.
        # The other elements (if present) are compression formats

        if elems_spec != []:  # FIXME: support elems
            if format_spec != []:
                evaluation.message(
                    "ExportString", "noelem", elems, String(format_spec[0])
                )
            else:
                evaluation.message("ExportString", "noelem", elems, String("Unknown"))
            evaluation.predetermined_out = current_predetermined_out
            return SymbolFailed

        # Load the exporter
        exporter_symbol, exporter_options = EXPORTERS[format_spec[0]]
        function_channels = exporter_options.get("System`FunctionChannels")

        stream_options, custom_options = _importer_exporter_options(
            exporter_options.get("System`Options"),
            options,
            "System Options",
            evaluation,
        )

        is_binary = exporter_options["System`BinaryFormat"].is_true()
        if function_channels is None:
            evaluation.message("ExportString", "emptyfch")
            evaluation.predetermined_out = current_predetermined_out
            return SymbolFailed
        elif function_channels == Expression(SymbolList, String("FileNames")):
            # Generates a temporary file
            import tempfile

            tmpfile = tempfile.NamedTemporaryFile(
                dir=tempfile.gettempdir(), suffix="." + format_spec[0].lower()
            )
            filename = String(tmpfile.name)
            tmpfile.close()
            exporter_function = Expression(
                exporter_symbol,
                filename,
                expr,
                *list(chain(stream_options, custom_options))
            )
            exportres = exporter_function.evaluate(evaluation)
            if exportres != Symbol("Null"):
                evaluation.predetermined_out = current_predetermined_out
                return SymbolFailed
            else:
                try:
                    if is_binary:
                        tmpstream = open(filename.value, "rb")
                    else:
                        tmpstream = open(filename.value, "r")
                    res = tmpstream.read()
                    tmpstream.close()
                except Exception as e:
                    print("something went wrong")
                    print(e)
                    evaluation.predetermined_out = current_predetermined_out
                    return SymbolFailed
                if is_binary:
                    res = Expression("ByteArray", ByteArrayAtom(res))
                else:
                    res = String(str(res))
        elif function_channels == Expression(SymbolList, String("Streams")):
            from io import StringIO, BytesIO

            if is_binary:
                pystream = BytesIO()
            else:
                pystream = StringIO()

            name = "ExportString"
            stream = stream_manager.add(name, mode="w", io=pystream)
            outstream = Expression("OutputStream", String("String"), Integer(stream.n))
            exporter_function = Expression(
                exporter_symbol,
                outstream,
                expr,
                *list(chain(stream_options, custom_options))
            )
            res = exporter_function.evaluate(evaluation)
            if res == SymbolNull:
                if is_binary:
                    res = Expression("ByteArray", ByteArrayAtom(pystream.getvalue()))
                else:
                    res = String(str(pystream.getvalue()))
            else:
                res = Symbol("$Failed")
            Expression("Close", outstream).evaluate(evaluation)
        else:
            evaluation.message("ExportString", "emptyfch")
            evaluation.predetermined_out = current_predetermined_out
            return SymbolFailed

        evaluation.predetermined_out = current_predetermined_out
        return res


class FileFormat(Builtin):
    """
    <dl>
    <dt>'FileFormat["$name$"]'
      <dd>attempts to determine what format 'Import' should use to import specified file.
    </dl>

    >> FileFormat["ExampleData/sunflowers.jpg"]
     = JPEG

    ## UTF-8 Unicode text
    >> FileFormat["ExampleData/EinsteinSzilLetter.txt"]
     = Text

    >> FileFormat["ExampleData/lena.tif"]
     = TIFF

    ## ASCII text
    #> FileFormat["ExampleData/BloodToilTearsSweat.txt"]
     = Text
    #> FileFormat["ExampleData/MadTeaParty.gif"]
     = GIF
    #> FileFormat["ExampleData/moon.tif"]
     = TIFF

    #> FileFormat["ExampleData/numberdata.csv"]
     = CSV

    #> FileFormat["ExampleData/EinsteinSzilLetter.txt"]
     = Text

    #> FileFormat["ExampleData/BloodToilTearsSweat.txt"]
     = Text

    ## Doesn't work on Microsoft Windows
    ## S> FileFormat["ExampleData/benzene.xyz"]
    ##  = XYZ

    #> FileFormat["ExampleData/colors.json"]
     = JSON

    #> FileFormat["ExampleData/some-typo.extension"]
     : File not found during FileFormat[ExampleData/some-typo.extension].
     = $Failed

    #> FileFormat["ExampleData/Testosterone.svg"]
     = SVG

    #> FileFormat["ExampleData/colors.json"]
     = JSON

    #> FileFormat["ExampleData/InventionNo1.xml"]
     = XML
    """

    messages = {
        "nffil": "File not found during `1`.",
    }

    detector = None

    def apply(self, filename, evaluation):
        "FileFormat[filename_String]"

        findfile = Expression("FindFile", filename).evaluate(evaluation)
        if findfile == SymbolFailed:
            evaluation.message(
                "FileFormat", "nffil", Expression("FileFormat", filename)
            )
            return findfile

        path = findfile.get_string_value()
        if not FileFormat.detector:
            loader = magic.MagicLoader()
            loader.load()
            FileFormat.detector = magic.MagicDetector(loader.mimetypes)

        mime = set(FileFormat.detector.match(path))

        # If match fails match on extension only
        if mime == set([]):
            mime, encoding = mimetypes.guess_type(path)
            if mime is None:
                mime = set([])
            else:
                mime = set([mime])
        result = []
        for key in mimetype_dict.keys():
            if key in mime:
                result.append(mimetype_dict[key])

        # the following fixes an extremely annoying behaviour on some (not all)
        # installations of Windows, where we end up classifying .csv files als XLS.
        if len(result) == 1 and result[0] == "XLS" and path.lower().endswith(".csv"):
            return String("CSV")

        if len(result) == 0:
            result = "Binary"
        elif len(result) == 1:
            result = result[0]
        else:
            return None

        return from_python(result)


import base64


class B64Encode(Builtin):
    """
    <dl>
    <dt> 'System`Convert`B64Dump`B64Encode[$expr$]'
    <dd>Encodes $expr$ in Base64 coding
    </dl>

    >> System`Convert`B64Dump`B64Encode["Hello world"]
     = SGVsbG8gd29ybGQ=
    >> System`Convert`B64Dump`B64Decode[%]
     = Hello world
    >> System`Convert`B64Dump`B64Encode[Integrate[f[x],{x,0,2}]]
     = SW50ZWdyYXRlW2ZbeF0sIHt4LCAwLCAyfV0=
    >> System`Convert`B64Dump`B64Decode[%]
     = Integrate[f[x], {x, 0, 2}]
    """

    context = "System`Convert`B64Dump`"
    name = "B64Encode"

    def apply(self, expr, evaluation):
        "System`Convert`B64Dump`B64Encode[expr_]"
        if isinstance(expr, String):
            stringtocodify = expr.get_string_value()
        elif expr.get_head_name() == "System`ByteArray":
            return String(expr._leaves[0].__str__())
        else:
            stringtocodify = (
                Expression("ToString", expr).evaluate(evaluation).get_string_value()
            )
        return String(
            base64.b64encode(bytearray(stringtocodify, "utf8")).decode("utf8")
        )


class B64Decode(Builtin):
    """
    <dl>
    <dt> 'System`Convert`B64Dump`B64Decode[$string$]'
    <dd>Decode  $string$ in Base64 coding to an expression.
    </dl>

    >> System`Convert`B64Dump`B64Decode["R!="]
     : String "R!=" is not a valid b64 encoded string.
     = $Failed
    """

    context = "System`Convert`B64Dump`"
    name = "B64Decode"

    messages = {
        "b64invalidstr": 'String "`1`" is not a valid b64 encoded string.',
    }

    def apply(self, expr, evaluation):
        "System`Convert`B64Dump`B64Decode[expr_String]"
        try:
            clearstring = base64.b64decode(
                bytearray(expr.get_string_value(), "utf8")
            ).decode("utf8")
            clearstring = String(str(clearstring))
        except Exception:
            evaluation.message(
                "System`Convert`B64Dump`B64Decode", "b64invalidstr", expr
            )
            return Symbol("$Failed")
        return clearstring


class ConvertCommonDumpRemoveLinearSyntax(Builtin):
    """
    <dl>
    <dt> 'System`Convert`CommonDump`RemoveLinearSyntax[$something$]'
    <dd> Keine anung... Undocumented in wma
    </dl>
    """

    options = {
        "System`Convert`CommonDump`ConvertRecursive": "False",
    }
    # options = {"ConvertRecursive" : "False", }
    attributes = ("ReadProtected",)
    context = "System`Convert`CommonDump`"
    name = "RemoveLinearSyntax"

    def apply(self, arg, evaluation):
        "System`Convert`CommonDump`RemoveLinearSyntax[arg_]"
        print("No idea what should this do. By now, do nothing...")
        return arg
