"""
This module provides routines to adjust subplot params so that subplots are
nicely fit in the figure. In doing so, only axis labels, tick labels, axes
titles and offsetboxes that are anchored to axes are currently considered.

Internally, it assumes that the margins (left_margin, etc.) which are
differences between ax.get_tightbbox and ax.bbox are independent of axes
position. This may fail if Axes.adjustable is datalim. Also, This will fail
for some cases (for example, left or right margin is affected by xlabel).
"""

import warnings

import matplotlib
from matplotlib.transforms import TransformedBbox, Bbox

from matplotlib.font_manager import FontProperties
rcParams = matplotlib.rcParams


def _get_left(tight_bbox, axes_bbox):
    return axes_bbox.xmin - tight_bbox.xmin


def _get_right(tight_bbox, axes_bbox):
    return tight_bbox.xmax - axes_bbox.xmax


def _get_bottom(tight_bbox, axes_bbox):
    return axes_bbox.ymin - tight_bbox.ymin


def _get_top(tight_bbox, axes_bbox):
    return tight_bbox.ymax - axes_bbox.ymax


def auto_adjust_subplotpars(fig, renderer,
                            nrows_ncols,
                            num1num2_list,
                            subplot_list,
                            ax_bbox_list=None,
                            pad=1.08, h_pad=None, w_pad=None,
                            rect=None):
    """
    Return a dictionary of subplot parameters so that spacing between
    subplots are adjusted. Note that this function ignore geometry
    information of subplot itself, but uses what is given by
    *nrows_ncols* and *num1num2_list* parameteres. Also, the results could be
    incorrect if some subplots have ``adjustable=datalim``.

    Parameters:

    nrows_ncols
      number of rows and number of columns of the grid.

    num1num2_list
      list of numbers specifying the area occupied by the subplot

    subplot_list
      list of subplots that will be used to calcuate optimal subplot_params.

    pad : float
      padding between the figure edge and the edges of subplots, as a fraction
      of the font-size.
    h_pad, w_pad : float
      padding (height/width) between edges of adjacent subplots.
        Defaults to `pad_inches`.

    rect
      [left, bottom, right, top] in normalized (0, 1) figure coordinates.
    """
    rows, cols = nrows_ncols

    pad_inches = pad * FontProperties(
                    size=rcParams["font.size"]).get_size_in_points() / 72.

    if h_pad is not None:
        vpad_inches = h_pad * FontProperties(
                        size=rcParams["font.size"]).get_size_in_points() / 72.
    else:
        vpad_inches = pad_inches

    if w_pad is not None:
        hpad_inches = w_pad * FontProperties(
                        size=rcParams["font.size"]).get_size_in_points() / 72.
    else:
        hpad_inches = pad_inches

    if len(subplot_list) == 0:
        raise RuntimeError("")

    if len(num1num2_list) != len(subplot_list):
        raise RuntimeError("")

    if rect is None:
        margin_left = None
        margin_bottom = None
        margin_right = None
        margin_top = None
    else:
        margin_left, margin_bottom, _right, _top = rect
        if _right:
            margin_right = 1. - _right
        else:
            margin_right = None
        if _top:
            margin_top = 1. - _top
        else:
            margin_top = None

    vspaces = [[] for i in range((rows + 1) * cols)]
    hspaces = [[] for i in range(rows * (cols + 1))]

    union = Bbox.union

    if ax_bbox_list is None:
        ax_bbox_list = []
        for subplots in subplot_list:
            ax_bbox = union([ax.get_position(original=True)
                             for ax in subplots])
            ax_bbox_list.append(ax_bbox)

    for subplots, ax_bbox, (num1, num2) in zip(subplot_list,
                                               ax_bbox_list,
                                               num1num2_list):
        if all([not ax.get_visible() for ax in subplots]):
            continue

        tight_bbox_raw = union([ax.get_tightbbox(renderer) for ax in subplots
                                if ax.get_visible()])
        tight_bbox = TransformedBbox(tight_bbox_raw,
                                     fig.transFigure.inverted())

        row1, col1 = divmod(num1, cols)

        if num2 is None:
            # left
            hspaces[row1 * (cols + 1) + col1].append(
                                        _get_left(tight_bbox, ax_bbox))
            # right
            hspaces[row1 * (cols + 1) + (col1 + 1)].append(
                                        _get_right(tight_bbox, ax_bbox))
            # top
            vspaces[row1 * cols + col1].append(
                                        _get_top(tight_bbox, ax_bbox))
            # bottom
            vspaces[(row1 + 1) * cols + col1].append(
                                        _get_bottom(tight_bbox, ax_bbox))

        else:
            row2, col2 = divmod(num2, cols)

            for row_i in range(row1, row2 + 1):
                # left
                hspaces[row_i * (cols + 1) + col1].append(
                                    _get_left(tight_bbox, ax_bbox))
                # right
                hspaces[row_i * (cols + 1) + (col2 + 1)].append(
                                    _get_right(tight_bbox, ax_bbox))
            for col_i in range(col1, col2 + 1):
                # top
                vspaces[row1 * cols + col_i].append(
                                    _get_top(tight_bbox, ax_bbox))
                # bottom
                vspaces[(row2 + 1) * cols + col_i].append(
                                    _get_bottom(tight_bbox, ax_bbox))

    fig_width_inch, fig_height_inch = fig.get_size_inches()

    # margins can be negative for axes with aspect applied. And we
    # append + [0] to make minimum margins 0

    if not margin_left:
        margin_left = max([sum(s) for s in hspaces[::cols + 1]] + [0])
        margin_left += pad_inches / fig_width_inch

    if not margin_right:
        margin_right = max([sum(s) for s in hspaces[cols::cols + 1]] + [0])
        margin_right += pad_inches / fig_width_inch

    if not margin_top:
        margin_top = max([sum(s) for s in vspaces[:cols]] + [0])
        margin_top += pad_inches / fig_height_inch

    if not margin_bottom:
        margin_bottom = max([sum(s) for s in vspaces[-cols:]] + [0])
        margin_bottom += pad_inches / fig_height_inch

    kwargs = dict(left=margin_left,
                  right=1 - margin_right,
                  bottom=margin_bottom,
                  top=1 - margin_top)

    if cols > 1:
        hspace = (
            max(sum(s)
                for i in range(rows)
                for s in hspaces[i * (cols + 1) + 1:(i + 1) * (cols + 1) - 1])
            + hpad_inches / fig_width_inch)
        h_axes = (1 - margin_right - margin_left - hspace * (cols - 1)) / cols
        kwargs["wspace"] = hspace / h_axes

    if rows > 1:
        vspace = (max(sum(s) for s in vspaces[cols:-cols])
                  + vpad_inches / fig_height_inch)
        v_axes = (1 - margin_top - margin_bottom - vspace * (rows - 1)) / rows
        kwargs["hspace"] = vspace / v_axes

    return kwargs


def get_renderer(fig):
    if fig._cachedRenderer:
        renderer = fig._cachedRenderer
    else:
        canvas = fig.canvas

        if canvas and hasattr(canvas, "get_renderer"):
            renderer = canvas.get_renderer()
        else:
            # not sure if this can happen
            warnings.warn("tight_layout : falling back to Agg renderer")
            from matplotlib.backends.backend_agg import FigureCanvasAgg
            canvas = FigureCanvasAgg(fig)
            renderer = canvas.get_renderer()

    return renderer


def get_subplotspec_list(axes_list, grid_spec=None):
    """Return a list of subplotspec from the given list of axes.

    For an instance of axes that does not support subplotspec, None is inserted
    in the list.

    If grid_spec is given, None is inserted for those not from the given
    grid_spec.
    """
    subplotspec_list = []
    for ax in axes_list:
        axes_or_locator = ax.get_axes_locator()
        if axes_or_locator is None:
            axes_or_locator = ax

        if hasattr(axes_or_locator, "get_subplotspec"):
            subplotspec = axes_or_locator.get_subplotspec()
            subplotspec = subplotspec.get_topmost_subplotspec()
            gs = subplotspec.get_gridspec()
            if grid_spec is not None:
                if gs != grid_spec:
                    subplotspec = None
            elif gs.locally_modified_subplot_params():
                subplotspec = None
        else:
            subplotspec = None

        subplotspec_list.append(subplotspec)

    return subplotspec_list


def get_tight_layout_figure(fig, axes_list, subplotspec_list, renderer,
                            pad=1.08, h_pad=None, w_pad=None, rect=None):
    """
    Return subplot parameters for tight-layouted-figure with specified
    padding.

    Parameters:

      *fig* : figure instance

      *axes_list* : a list of axes

      *subplotspec_list* : a list of subplotspec associated with each
        axes in axes_list

      *renderer* : renderer instance

      *pad* : float
        padding between the figure edge and the edges of subplots,
        as a fraction of the font-size.

      *h_pad*, *w_pad* : float
        padding (height/width) between edges of adjacent subplots.
        Defaults to `pad_inches`.

      *rect* : if rect is given, it is interpreted as a rectangle
        (left, bottom, right, top) in the normalized figure
        coordinate that the whole subplots area (including
        labels) will fit into. Default is (0, 0, 1, 1).
    """

    subplot_list = []
    nrows_list = []
    ncols_list = []
    ax_bbox_list = []

    subplot_dict = {}  # multiple axes can share
                       # same subplot_interface (e.g., axes_grid1). Thus
                       # we need to join them together.

    subplotspec_list2 = []

    for ax, subplotspec in zip(axes_list,
                               subplotspec_list):
        if subplotspec is None:
            continue

        subplots = subplot_dict.setdefault(subplotspec, [])

        if not subplots:
            myrows, mycols, _, _ = subplotspec.get_geometry()
            nrows_list.append(myrows)
            ncols_list.append(mycols)
            subplotspec_list2.append(subplotspec)
            subplot_list.append(subplots)
            ax_bbox_list.append(subplotspec.get_position(fig))

        subplots.append(ax)

    if (len(nrows_list) == 0) or (len(ncols_list) == 0):
        return {}

    max_nrows = max(nrows_list)
    max_ncols = max(ncols_list)

    num1num2_list = []
    for subplotspec in subplotspec_list2:
        rows, cols, num1, num2 = subplotspec.get_geometry()
        div_row, mod_row = divmod(max_nrows, rows)
        div_col, mod_col = divmod(max_ncols, cols)
        if (mod_row != 0) or (mod_col != 0):
            raise RuntimeError("")

        rowNum1, colNum1 = divmod(num1, cols)
        if num2 is None:
            rowNum2, colNum2 = rowNum1, colNum1
        else:
            rowNum2, colNum2 = divmod(num2, cols)

        num1num2_list.append((rowNum1 * div_row * max_ncols +
                              colNum1 * div_col,
                              ((rowNum2 + 1) * div_row - 1) * max_ncols +
                              (colNum2 + 1) * div_col - 1))

    kwargs = auto_adjust_subplotpars(fig, renderer,
                                     nrows_ncols=(max_nrows, max_ncols),
                                     num1num2_list=num1num2_list,
                                     subplot_list=subplot_list,
                                     ax_bbox_list=ax_bbox_list,
                                     pad=pad, h_pad=h_pad, w_pad=w_pad)

    if rect is not None:
        # if rect is given, the whole subplots area (including
        # labels) will fit into the rect instead of the
        # figure. Note that the rect argument of
        # *auto_adjust_subplotpars* specify the area that will be
        # covered by the total area of axes.bbox. Thus we call
        # auto_adjust_subplotpars twice, where the second run
        # with adjusted rect parameters.

        left, bottom, right, top = rect
        if left is not None:
            left += kwargs["left"]
        if bottom is not None:
            bottom += kwargs["bottom"]
        if right is not None:
            right -= (1 - kwargs["right"])
        if top is not None:
            top -= (1 - kwargs["top"])

        #if h_pad is None: h_pad = pad
        #if w_pad is None: w_pad = pad

        kwargs = auto_adjust_subplotpars(fig, renderer,
                                         nrows_ncols=(max_nrows, max_ncols),
                                         num1num2_list=num1num2_list,
                                         subplot_list=subplot_list,
                                         ax_bbox_list=ax_bbox_list,
                                         pad=pad, h_pad=h_pad, w_pad=w_pad,
                                         rect=(left, bottom, right, top))

    return kwargs
