from __future__ import (absolute_import, division, print_function,
                        unicode_literals)

import pandas as pd
import pandas.core.common as com
import numpy as np
import matplotlib.pyplot as plt
import matplotlib as mpl
import matplotlib.gridspec as gridspec

from .components import aes, assign_visual_mapping
from .components import colors, shapes
from .components.legend import add_legend
from .scales.scale_facet import scale_facet_grid, scale_facet_wrap
from .scales.utils import calc_axis_breaks_and_limits
from .themes.theme_gray import theme_gray

import six

__all__ = ["ggplot"]
__all__ = [str(u) for u in __all__]

import sys
import warnings
from copy import deepcopy

# Show plots if in interactive mode
if sys.flags.interactive:
    plt.ion()

# Workaround for matplotlib 1.1.1 not having a rc_context
if not hasattr(mpl, 'rc_context'):
    from .utils import _rc_context
    mpl.rc_context = _rc_context

class ggplot(object):
    """
    ggplot is the base layer or object that you use to define
    the components of your chart (x and y axis, shapes, colors, etc.).
    You can combine it with layers (or geoms) to make complex graphics
    with minimal effort.

    Parameters
    -----------
    aesthetics :  aes (ggplot.components.aes.aes)
        aesthetics of your plot
    data :  pandas DataFrame (pd.DataFrame)
        a DataFrame with the data you want to plot

    Examples
    ----------
    >>> p = ggplot(aes(x='x', y='y'), data=diamonds)
    >>> print(p + geom_point())
    """

    CONTINUOUS = ['x', 'y', 'size', 'alpha']
    DISCRETE = ['color', 'shape', 'marker', 'alpha', 'linestyle']

    def __init__(self, aesthetics, data):
        # ggplot should just 'figure out' which is which
        if not isinstance(data, pd.DataFrame):
            aesthetics, data = data, aesthetics

        self.aesthetics = aesthetics
        self.data = _apply_transforms(data, self.aesthetics)

        # defaults
        self.geoms = []
        self.n_rows = 1
        self.n_columns = 1
        self.n_dim_x = None
        self.n_dim_y = None
        # facets
        self.facets = []
        self.facet_type = None
        self.facet_scales = None
        self.facet_pairs = [] # used by facet_grid
        # components
        self.title = None
        self.xlab = None
        self.ylab = None
        # format for x/y major ticks
        self.xtick_formatter = None
        self.xbreaks = None
        self.xtick_labels = None
        self.xmajor_locator = None
        self.xminor_locator = None
        self.ytick_formatter = None
        self.xlimits = None
        self.ylimits = None
        self.ytick_labels = None
        self.scale_y_reverse = None
        self.scale_x_reverse = None
        self.scale_y_log = None
        self.scale_x_log = None
        self.legend = None
        # coords
        self.coord_equal = None

        # default theme is theme_gray
        self.theme = theme_gray()

        # continuous color configs
        self.color_scale = None
        self.colormap = plt.cm.Blues
        self.manual_color_list = None

    def __repr__(self):
        """Print/show the plot"""
        figure = self.draw()
        # We're going to default to making the plot appear when __repr__ is
        # called.
        #figure.show() # doesn't work in ipython notebook
        plt.show()
        # TODO: We can probably get more sugary with this
        return "<ggplot: (%d)>" % self.__hash__()

    def __deepcopy__(self, memo):
        '''deepcopy support for ggplot'''
        # This is a workaround as ggplot(None, None) does not really work :-(
        class _empty(object):
            pass
        result = _empty()
        result.__class__ = self.__class__
        for key, item in self.__dict__.items():
            # don't make a deepcopy of data!
            if key == "data":
                result.__dict__[key] = self.__dict__[key]
                continue
            result.__dict__[key] = deepcopy(self.__dict__[key], memo)

        return result

    def draw(self):
        # Adding rc=self.rcParams does not validate/parses the params which then
        # throws an error during plotting!
        with mpl.rc_context():
            # Use a throw away rcParams, so subsequent plots will not have any
            # residual from this plot
            # @todo: change it to something more like
            # rcParams = theme.get_rcParams()
            rcParams = self.theme.get_rcParams()
            for key in six.iterkeys(rcParams):
                val = rcParams[key]
                # there is a bug in matplotlib which does not allow None directly
                # https://github.com/matplotlib/matplotlib/issues/2543
                try:
                    if key == 'text.dvipnghack' and val is None:
                        val = "none"
                    mpl.rcParams[key] = val
                except Exception as e:
                    msg = """Setting "mpl.rcParams['%s']=%s" raised an Exception: %s""" % (key, str(val), str(e))
                    warnings.warn(msg, RuntimeWarning)
            # draw is not allowed to show a plot, so we can use to result for ggsave
            # This sets a rcparam, so we don't have to undo it after plotting
            mpl.interactive(False)
            if self.facet_type == "grid" and len(self.facets) > 1:
                fig, axs = plt.subplots(self.n_columns, self.n_rows,
                                        sharex=True, sharey=True)
                plt.subplots_adjust(wspace=.05, hspace=.05)
            elif self.facet_type == "wrap" or len(self.facets)==1:
                # add (more than) the needed number of subplots
                fig, axs = plt.subplots(self.n_columns, self.n_rows)
                # there are some extra, remove the plots
                subplots_available = self.n_rows * self.n_columns
                if self.n_dim_x:
                    extra_subplots = subplots_available - self.n_dim_x
                else:
                    extra_subplots = 0
                if extra_subplots > 0:
                    for extra_plot in axs.flatten()[-extra_subplots:]:
                        extra_plot.axis('off')

                # plots is a mapping from xth-plot -> subplot position
                plots = []
                for x in range(self.n_rows):
                    for y in range(self.n_columns):
                        plots.append((x, y))
                plots = sorted(plots, key=lambda x: x[1] + x[0] * self.n_columns + 1)
            else:
                fig, axs = plt.subplots(self.n_columns, self.n_rows)
            axs = np.atleast_2d(axs)
            # Set the default plot to the first one
            plt.subplot(self.n_rows, self.n_columns, 1)

            # Aes need to be initialized BEFORE we start faceting. This is b/c
            # we want to have a consistent aes mapping across facets.
            self.data, self.legend = assign_visual_mapping(self.data, self.aesthetics, self)

            # Faceting just means doing an additional groupby. The
            # dimensions of the plot remain the same
            if self.facets:
                # geom_bar does not work with faceting yet
                from .geoms import geom_bar
                _check_geom_bar = lambda x :isinstance(x, geom_bar)
                if any(map(_check_geom_bar, self.geoms)):
                    msg = """Facetting is currently not supported with geom_bar. See
                    https://github.com/yhat/ggplot/issues/196 for more information"""
                    warnings.warn(msg, RuntimeWarning)
                # the current subplot in the axs and plots
                cntr = 0
                #first grids: faceting with two variables and defined positions
                if len(self.facets) == 2 and self.facet_type != "wrap":
                    # store the extreme x and y coordinates of each pair of axes
                    axis_extremes = np.zeros(shape=(self.n_columns * self.n_rows, 4))
                    xlab_offset = .15
                    for _iter, (facets, frame) in enumerate(self.data.groupby(self.facets)):
                        pos = self.facet_pairs.index(facets) + 1
                        plt.subplot(self.n_rows, self.n_columns, pos)
                        frame = self._make_plot_data(frame)
                        for geom in self.geoms:
                            ax = plt.gca()
                            callbacks = geom.plot_layer(frame, ax)
                        axis_extremes[_iter] = [min(plt.xlim()), max(plt.xlim()),
                                                min(plt.ylim()), max(plt.ylim())]
                    # find the grid wide data extremeties
                    xlab_min, ylab_min = np.min(axis_extremes, axis=0)[[0, 2]]
                    xlab_max, ylab_max = np.max(axis_extremes, axis=0)[[1, 3]]
                    # position of vertical labels for facet grid
                    xlab_pos = xlab_max + xlab_offset
                    ylab_pos = ylab_max - float(ylab_max - ylab_min) / 2
                    # This needs to enumerate all possibilities
                    for pos, facets in enumerate(self.facet_pairs):
                        pos += 1
                        # Plot the top and right boxes
                        if pos <= self.n_columns: # first row
                            plt.subplot(self.n_rows, self.n_columns, pos)
                            plt.table(cellText=[[facets[1]]], loc='top',
                                      cellLoc='center', cellColours=[['lightgrey']])
                        if (pos % self.n_columns) == 0: # last plot in a row
                            plt.subplot(self.n_rows, self.n_columns, pos)
                            x = max(plt.xticks()[0])
                            y = max(plt.yticks()[0])
                            ax = axs[pos % self.n_columns][pos % self.n_rows]
                            ax = plt.gca()
                            ax.text(1, 0.5, facets[0],
                                    # NOTE: bbox colors are buggy for python 3.3
                                    # color overides facecolor and edgecolor
                                    # instead of the opposite
                                     bbox=dict(
                                         facecolor='lightgrey',
                                         edgecolor='black',
                                         width=mpl.rcParams['font.size'] * 1.65
                                     ),
                                     transform=ax.transAxes,
                                     fontdict=dict(rotation=-90, verticalalignment="center", horizontalalignment='left')
                            )

                    plt.subplot(self.n_rows, self.n_columns, pos)
                    # Handle the different scale types here
                    # (free|free_y|free_x|None) and also make sure that only the
                    # left column gets y scales and the bottom row gets x scales
                    scale_facet_grid(self.n_rows, self.n_columns,
                                     self.facet_pairs, self.facet_scales)

                else: # now facet_wrap > 2 or facet_grid w/ only 1 facet

                    for facet, frame in self.data.groupby(self.facets):
                        frame = self._make_plot_data(frame)
                        for geom in self.geoms:
                            if self.facet_type == "wrap" or 1==1:
                                if cntr + 1 > len(plots):
                                    continue
                                pos = plots[cntr]
                                if pos is None:
                                    continue
                                y_i, x_i = pos
                                pos = x_i + y_i * self.n_columns + 1
                                ax = plt.subplot(self.n_rows, self.n_columns, pos)
                            else:
                                ax = plt.subplot(self.n_rows, self.n_columns, cntr)
                                # TODO: this needs some work
                                if (cntr % self.n_columns) == -1:
                                    plt.tick_params(axis='y', which='both',
                                                    bottom='off', top='off',
                                                    labelbottom='off')
                            ax = plt.gca()
                            callbacks = geom.plot_layer(frame, ax)
                            if callbacks:
                                for callback in callbacks:
                                    fn = getattr(ax, callback['function'])
                                    fn(*callback['args'])
                        title = facet
                        if isinstance(facet, tuple):
                            title = ", ".join(facet)
                        plt.table(cellText=[[title]], loc='top',
                                  cellLoc='center', cellColours=[['lightgrey']])
                        cntr += 1

                    scale_facet_wrap(self.n_rows, self.n_columns, range(cntr), self.facet_scales)
            else: # no faceting
                for geom in self.geoms:
                    _aes = self.aesthetics
                    if geom.aes:
                        # update the default mapping with the geom specific one
                        _aes = _aes.copy()
                        _aes.update(geom.aes)
                    if not geom.data is None:
                        data = _apply_transforms(geom.data, _aes)
                        data, self.legend = assign_visual_mapping(data, _aes, self)
                    else:
                        data = self.data
                    ax = plt.subplot(1, 1, 1)

                    data = self._make_plot_data(data, _aes)
                    callbacks = geom.plot_layer(data, ax)
                    if callbacks:
                        for callback in callbacks:
                            fn = getattr(ax, callback['function'])
                            fn(*callback['args'])

            # Handling the details of the chart here; probably be a better
            # way to do this...
            if self.title:
                if self.facets:
                    # This is currently similar what plt.title uses
                    plt.gcf().suptitle(self.title, verticalalignment='baseline',
                                       fontsize=mpl.rcParams['axes.titlesize'])
                else:
                    plt.title(self.title)
            if not (self.xlab is None):
                if self.facet_type == "grid":
                    fig.text(0.5, 0.025, self.xlab)
                else:
                    for ax in plt.gcf().axes:
                        ax.set_xlabel(self.xlab)
            if not (self.ylab is None):
                if self.facet_type == "grid":
                    fig.text(0.025, 0.5, self.ylab, rotation='vertical')
                else:
                    for ax in plt.gcf().axes:
                        ax.set_ylabel(self.ylab)
            # in case of faceting, this should be applied to all axis!
            for ax in plt.gcf().axes:
                if self.xmajor_locator:
                    ax.xaxis.set_major_locator(self.xmajor_locator)
                if self.xtick_formatter:
                    ax.xaxis.set_major_formatter(self.xtick_formatter)
                    fig.autofmt_xdate()
                if self.xbreaks: # xbreaks is a list manually provided
                    ax.xaxis.set_ticks(self.xbreaks)
                if not (self.xtick_labels is None):
                    if isinstance(self.xtick_labels, dict):
                        labs = []
                        for lab in plt.xticks()[1]:
                            lab = lab.get_text()
                            lab = self.xtick_labels.get(lab)
                            labs.append(lab)
                        ax.xaxis.set_ticklabels(labs)
                    elif com.is_list_like(self.xtick_labels):
                        ax.xaxis.set_ticklabels(self.xtick_labels)
                if not (self.ytick_labels is None):
                    if isinstance(self.ytick_labels, dict):
                        labs = []
                        for lab in plt.yticks()[1]:
                            lab = lab.get_text()
                            lab = self.ytick_labels.get(lab)
                            labs.append(lab)
                        ax.yaxis.set_ticklabels(labs)
                    elif com.is_list_like(self.ytick_labels):
                        ax.yaxis.set_ticklabels(self.ytick_labels)
                if self.ytick_formatter:
                    ax.yaxis.set_major_formatter(self.ytick_formatter)
                if not (self.xlimits is None):
                    limits = [x if x != None else x_def for x, x_def in zip(self.xlimits, ax.get_xlim())]
                    if (self.xbreaks is None) and (self.xtick_labels is None):
                        labs, minval, maxval= calc_axis_breaks_and_limits(limits[0], limits[1])
                        ax.xaxis.set_ticks(labs)
                        ax.xaxis.set_ticklabels(labs)
                    ax.set_xlim(limits)
                if not (self.ylimits is None):
                    limits = [y if y != None else y_def for y, y_def in zip(self.ylimits, ax.get_ylim())]
                    if self.ytick_labels is None:
                        labs, minval, maxval= calc_axis_breaks_and_limits(limits[0], limits[1])
                        ax.yaxis.set_ticks(labs)
                        ax.yaxis.set_ticklabels(labs)
                    ax.set_ylim(limits)
                if self.scale_y_reverse:
                    ax.invert_yaxis()
                if self.scale_x_reverse:
                    ax.invert_xaxis()
                if self.scale_y_log:
                    ax.set_yscale('log', basey=self.scale_y_log)
                if self.scale_x_log:
                    ax.set_xscale('log', basex=self.scale_x_log)
                if self.coord_equal:
                    min_val = np.min([np.min(ax.get_yticks()), np.min(ax.get_xticks())])
                    max_val = np.max([np.max(ax.get_yticks()), np.max(ax.get_xticks())])
                    ax.set_xticks(np.linspace(min_val, max_val, 7))
                    ax.set_yticks(np.linspace(min_val, max_val, 7))

            # TODO: Having some issues here with things that shouldn't have a
            # legend or at least shouldn't get shrunk to accomodate one. Need
            # some sort of test in place to prevent this OR prevent legend
            # getting set to True.
            if self.legend:
                # works with faceted and non-faceted plots
                ax = axs[0][self.n_rows - 1]
                box = ax.get_position()
                ax.set_position([box.x0, box.y0, box.width * 0.8, box.height])
                add_legend(self.legend, ax)

            # Finaly apply any post plot callbacks (theming, etc)
            for ax in plt.gcf().axes:
                self.theme.post_plot_callback(ax)

        return plt.gcf()

    def _make_plot_data(self, data=None, aes=None):
        # Use the default data and aestetics in case no specific ones are supplied
        if data is None:
            data = self.data
        if aes is None:
            aes = self.aesthetics

        mapping = {}
        extra = {}
        for ae, key in aes.items():
            if isinstance(key, list) or hasattr(key, "__array__"):
                # direct assignment of a list/array to the aes -> it's done in the get_layer step
                mapping[ae] = key
            elif key in data:
                # a column or a transformed column
                mapping[ae] = data[key]
            else:
                # now we have a single value. ggplot2 treats that as if all rows should be this
                # value, so lets do the same. To ensure that all rows get this value, we have to
                # do that after we constructed the dataframe.
                # See also the _apply_transform function below, which does this already for
                # string values.
                extra[ae] = key
        mapping = pd.DataFrame(mapping)
        for ae, key in extra.items():
            mapping[ae] = key

        # Overwrite the already done mappings to matplotlib understandable
        # values for color/size/etc
        for ae in ('alpha', 'color', 'fill', 'size', 'shape', 'linetype'):
            # TODO: Need to find a better way to avoid naming collisions
            _mcolumn = ':::%s_mapping:::' % ae
            if _mcolumn in data:
                mapping[ae] = data[_mcolumn]

        # Default the x and y axis labels to the name of the column
        if "x" in aes and self.xlab is None:
            self.xlab = aes['x']
        if "y" in aes and self.ylab is None:
            self.ylab = aes['y']

        # Automatically drop any row that has an NA value
        mapping = mapping.dropna()
        return mapping

    def add_to_legend(self, legend_type, legend_dict, scale_type="discrete"):
        """Adds the the specified legend to the legend

        Parameters
        ----------
        legend_type : str
            type of legend, one of "color", "linestyle", "marker", "size"
        legend_dict : dict
            a dictionary of {visual_value: legend_key} where visual_value
            is color value, line style, marker character, or size value;
            and legend_key is a quantile.
        scale_type : str
            either "discrete" (default) or "continuous"; usually only color
            needs to specify which kind of legend should be drawn, all
            other scales will get a discrete scale.
        """
        # scale_type is up to now unused
        # TODO: what happens if we add a second color mapping?
        # Currently the color mapping in the legend is overwritten.
        # What does ggplot do in such a case?
        if legend_type in self.legend:
            pass
            #msg = "Adding a secondary mapping of {0} is unsupported and no legend for this mapping is added.\n"
            #sys.stderr.write(msg.format(str(legend_type)))
        self.legend[legend_type] = legend_dict


def _is_identity(x):
    if x in colors.COLORS:
        return True
    elif x in shapes.SHAPES:
        return True
    elif isinstance(x, (float, int)):
        return True
    else:
        return False


def _apply_transforms(data, aes):
    """Adds columns from the aes included transformations

    Possible transformations are "factor(<col>)" and
    expressions which can be used with eval.

    Parameters
    ----------
    data : DataFrame
        the original dataframe
    aes : aesthetics
        the aesthetic

    Returns
    -------
    data : DateFrame
        Transformed DataFrame
    """
    data = data.copy()
    for ae, name in aes.items():
        if (isinstance(name, six.string_types) and (name not in data)):
            # here we assume that it is a transformation
            # if the mapping is to a single value (color="red"), this will be handled by pandas and
            # assigned to the whole index. See also the last case in mapping building in get_layer!
            from patsy.eval import EvalEnvironment
            def factor(s, levels=None, labels=None):
                # TODO: This factor implementation needs improvements...
                # probably only gonna happen after https://github.com/pydata/pandas/issues/5313 is
                # implemented in pandas ...
                if levels or labels:
                    print("factor levels or labels are not yet implemented.")
                return s.apply(str)
            # use either the captured eval_env from aes or use the env one steps up
            env = EvalEnvironment.capture(eval_env=(aes.__eval_env__ or 1))
            # add factor as a special case
            env.add_outer_namespace({"factor":factor})
            try:
                new_val = env.eval(name, inner_namespace=data)
            except Exception as e:
                msg = "Could not evaluate the '%s' mapping: '%s' (original error: %s)"
                raise Exception(msg % (ae, name, str(e)))
            try:
                data[name] = new_val
            except Exception as e:
                msg = """The '%s' mapping: '%s' produced a value of type '%s', but only single items
                and lists/arrays can be used. (original error: %s)"""
                raise Exception(msg % (ae, name, str(type(new_val)), str(e)))
    return data
