"""
    plotting.py
    The functions in this module are meant for plotting the histogram objects created via
    filval.histogram
"""

from collections import defaultdict
from itertools import zip_longest
from io import BytesIO
from base64 import b64encode
import numpy as np
import matplotlib.pyplot as plt
from markdown import Markdown
import latexipy as lp

from filval.histogram import (hist, hist2d, hist_bin_centers, hist_fit,
                              hist_norm, hist_stats)

__all__ = ['Plot',
           'decl_plot',
           'grid_plot',
           'render_plots',
           'generate_dashboard',
           'hist_plot',
           'hist_plot_stack',
           'hist2d_plot',
           'hists_to_table']


class Plot:
    def __init__(self, subplots, name, title=None, docs="N/A", arg_dicts=None):
        self.subplots = subplots
        self.name = name
        self.title = title
        self.docs = docs
        self.arg_dicts = arg_dicts if arg_dicts is not None else {}


MD = Markdown(extensions=['mdx_math'],
              extension_configs={'mdx_math': {'enable_dollar_delimiter': True}})

lp.latexify(params={'pgf.texsystem': 'pdflatex',
                    'text.usetex': True,
                    'font.family': 'serif',
                    'pgf.preamble': [],
                    'font.size': 15,
                    'axes.labelsize': 15,
                    'axes.titlesize': 13,
                    'legend.fontsize': 13,
                    'xtick.labelsize': 11,
                    'ytick.labelsize': 11,
                    'figure.dpi': 150,
                    'savefig.transparent': False,
                    },
            new_backend='TkAgg')


def _fn_call_to_dict(fn, *args, **kwargs):
    from inspect import signature
    from html import escape
    pnames = list(signature(fn).parameters)
    pvals = list(args) + list(kwargs.values())
    return {escape(str(k)): escape(str(v)) for k, v in zip(pnames, pvals)}


def _process_docs(fn):
    from inspect import getdoc
    raw = getdoc(fn)
    if raw:
        return MD.convert(raw)
    else:
        return None


def decl_plot(fn):
    from functools import wraps

    @wraps(fn)
    def f(*args, **kwargs):
        txt = fn(*args, **kwargs)
        argdict = _fn_call_to_dict(fn, *args, **kwargs)
        docs = _process_docs(fn)
        if not txt:
            txt = ''
        txt = MD.convert(txt)

        return argdict, docs, txt

    return f


def generate_dashboard(plots, title, output='dashboard.html', template='dashboard.j2',
                       source=None, ana_source=None, config=None):
    from jinja2 import Environment, PackageLoader, select_autoescape
    from os.path import join, isdir
    from os import mkdir
    from urllib.parse import quote

    env = Environment(
        loader=PackageLoader('filval', 'templates'),
        autoescape=select_autoescape(['htm', 'html', 'xml']),
    )
    env.globals.update({'quote': quote,
                        'enumerate': enumerate,
                        'zip': zip,
                        })

    def get_by_n(objects, n=2):
        objects = list(objects)
        while objects:
            yield objects[:n]
            objects = objects[n:]

    if source is not None:
        with open(source, 'r') as f:
            source = f.read()

    if config is not None:
        with open(config, 'r') as f:
            config = f.read()

    if not isdir('output'):
        mkdir('output')

    dashboard_path = join('output', output)
    with open(dashboard_path, 'w') as tempout:
        templ = env.get_template(template)
        tempout.write(templ.render(
            plots=get_by_n(plots, 3),
            title=title,
            source=source,
            ana_source=ana_source,
            config=config
        ))
    return dashboard_path


def _add_stats(hist, title=''):
    fmt = r'''\begin{{eqnarray*}}
\sum{{x_i}} &=& {sum:5.3f}                  \\
\sum{{\Delta x_i \cdot x_i}} &=& {int:5.3G} \\
\mu &=& {mean:5.3G}                         \\
\sigma^2 &=& {var:5.3G}                     \\
\sigma &=& {std:5.3G}
\end{{eqnarray*}}'''

    txt = fmt.format(**hist_stats(hist), title=title)
    txt = txt.replace('\n', ' ')

    plt.text(0.7, 0.9, txt,
             bbox={'facecolor': 'white',
                   'alpha': 0.7,
                   'boxstyle': 'square,pad=0.8'},
             transform=plt.gca().transAxes,
             verticalalignment='top',
             horizontalalignment='left',
             size='small')
    if title:
        plt.text(0.72, 0.97, title,
                 bbox={'facecolor': 'white',
                       'alpha': 0.8},
                 transform=plt.gca().transAxes,
                 verticalalignment='top',
                 horizontalalignment='left')


def grid_plot(subplots):
    if any(len(row) != len(subplots[0]) for row in subplots):
        raise ValueError('make_plot requires a rectangular list-of-lists as '
                         'input. Fill empty slots with None')

    def calc_row_span(fig, row, col):
        span = 1
        for r in range(row + 1, len(fig)):
            if fig[r][col] == 'FU':
                span += 1
            else:
                break
        return span

    def calc_column_span(fig, row, col):
        span = 1
        for c in range(col + 1, len(fig[row])):
            if fig[row][c] == 'FL':
                span += 1
            else:
                break
        return span

    rows = len(subplots)
    cols = len(subplots[0])

    argdicts = defaultdict(list)
    docs = defaultdict(list)
    txts = defaultdict(list)
    for i in range(rows):
        for j in range(cols):
            cell = subplots[i][j]
            if cell in ('FL', 'FU', None):
                continue
            if not isinstance(cell, list):
                cell = [cell]
            column_span = calc_column_span(subplots, i, j)
            row_span = calc_row_span(subplots, i, j)
            plt.subplot2grid((rows, cols), (i, j),
                             colspan=column_span, rowspan=row_span)
            for plot in cell:
                if len(plot) == 1:
                    plot_fn, args, kwargs = plot[0], (), {}
                elif len(plot) == 2:
                    plot_fn, args, kwargs = plot[0], plot[1], {}
                elif len(plot) == 3:
                    plot_fn, args, kwargs = plot[0], plot[1], plot[2]
                else:
                    raise ValueError('Plot tuple must be of format (func), '
                                     f'or (func, tuple), or (func, tuple, dict). Got {plot}')
                this_args, this_docs, txt = plot_fn(*args, **kwargs)
                argdicts[(i, j)].append(this_args)
                docs[(i, j)].append(this_docs)
                txts[(i, j)].append(txt)
    return argdicts, docs, txts


def render_plots(plots, exts=('png',), scale=1.0, to_disk=True):
    for plot in plots:
        print(f'Building plot {plot.name}')
        plot.data = None
        if to_disk:
            with lp.figure(plot.name.replace(' ', '_'), directory='output/figures',
                           exts=exts,
                           size=(scale * 10, scale * 10)):
                argdicts, docs, txts = grid_plot(plot.subplots)
        else:
            out = BytesIO()
            with lp.mem_figure(out,
                               ext=exts[0],
                               size=(scale * 10, scale * 10)):
                argdicts, docs, txts = grid_plot(plot.subplots)
            out.seek(0)
            plot.data = b64encode(out.read()).decode()
        plot.argdicts = argdicts
        plot.docs = docs
        plot.txts = txts


def add_decorations(axes, luminosity, energy):
    cms_prelim = r'{\raggedright{}\textsf{\textbf{CMS}}\\ \emph{Preliminary}}'
    axes.text(0.01, 0.98, cms_prelim,
              horizontalalignment='left',
              verticalalignment='top',
              transform=axes.transAxes)

    lumi = ""
    energy_str = ""
    if luminosity is not None:
        lumi = r'${} \mathrm{{fb}}^{{-1}}$'.format(luminosity)
    if energy is not None:
        energy_str = r'({} TeV)'.format(energy)

    axes.text(1, 1, ' '.join([lumi, energy_str]),
              horizontalalignment='right',
              verticalalignment='bottom',
              transform=axes.transAxes)


def hist_plot(h, *args, norm=None, include_errors=False,
              log=False, xlim=None, ylim=None, fit=None,
              grid=False, stats=False, **kwargs):
    """ Plots a 1D ROOT histogram object using matplotlib """
    from inspect import signature
    if norm:
        h = hist_norm(h, norm)
    values, errors, edges = h

    scale = 1. if norm is None else norm / np.sum(values)
    values = [val * scale for val in values]
    errors = [val * scale for val in errors]

    left, right = np.array(edges[:-1]), np.array(edges[1:])
    x = np.array([left, right]).T.flatten()
    y = np.array([values, values]).T.flatten()

    ax = plt.gca()

    ax.set_xlabel(kwargs.pop('xlabel', ''))
    ax.set_ylabel(kwargs.pop('ylabel', ''))
    title = kwargs.pop('title', '')
    if xlim is not None:
        ax.set_xlim(xlim)
    if ylim is not None:
        ax.set_ylim(ylim)
    # elif not log:
    #     axes.set_ylim((0, None))

    ax.plot(x, y, *args, linewidth=1, **kwargs)
    if include_errors:
        ax.errorbar(hist_bin_centers(h), values, yerr=errors,
                    color='k', marker=None, linestyle='None',
                    barsabove=True, elinewidth=.7, capsize=1)
    if log:
        ax.set_yscale('log')
    if fit:
        f, p0 = fit
        popt, pcov = hist_fit(h, f, p0)
        fit_xs = np.linspace(x[0], x[-1], 100)
        fit_ys = f(fit_xs, *popt)
        ax.plot(fit_xs, fit_ys, '--g')
        arglabels = list(signature(f).parameters)[1:]
        label_txt = "\n".join('{:7s}={: 0.2G}'.format(label, value)
                              for label, value in zip(arglabels, popt))
        ax.text(0.60, 0.95, label_txt, va='top', transform=ax.transAxes,
                fontsize='medium', family='monospace', usetex=False)
    if stats:
        _add_stats(h, title)
    else:
        ax.set_title(title)
    ax.grid(grid, color='#E0E0E0')


def hist2d_plot(h, txt_format=None, colorbar=False, **kwargs):
    """ Plots a 2D ROOT histogram object using matplotlib """
    try:
        values, errors, xs, ys = h
    except (TypeError, ValueError):
        values, errors, xs, ys = hist2d(h)

    plt.xlabel(kwargs.pop('xlabel', ''))
    plt.ylabel(kwargs.pop('ylabel', ''))
    plt.title(kwargs.pop('title', ''))
    plt.pcolormesh(xs, ys, values, **kwargs)
    if txt_format is not None:
        cmap = plt.get_cmap()
        min_, max_ = float(np.min(values)), float(np.max(values))

        def get_intensity(val):
            cmap_idx = int((cmap.N-1) * (val - min_) / (max_-min_))
            color = cmap.colors[cmap_idx]
            return color[0]*0.25 + color[1]*0.5 + color[2]*0.25

        for idx_row in range(values.shape[0]):
            for idx_col in range(values.shape[1]):
                x_mid = (xs[idx_row, idx_col] + xs[idx_row, idx_col+1]) / 2
                y_mid = (ys[idx_row, idx_col] + ys[idx_row+1, idx_col]) / 2
                val = txt_format.format(values[idx_row, idx_col])
                txt_color = 'w' if get_intensity(values[idx_row, idx_col]) < 0.5 else 'k'
                plt.text(x_mid, y_mid, val, verticalalignment='center', horizontalalignment='center',
                         color=txt_color, fontsize=12)
    if colorbar:
        plt.colorbar()


def hist_plot_stack(hists: list, labels: list = None):
    """
    Creates a stacked histogram in the current axes.

    :param hists: list of histogram
    :param labels:
    :return:
    """
    if len(hists) == 0:
        return

    if len(set([len(hist[0]) for hist in hists])) != 1:
        raise ValueError("all histograms must have the same number of bins")
    if labels is None:
        labels = [None for _ in hists]
    if len(labels) != len(hists):
        raise ValueError("Label mismatch")

    bottoms = [0 for _ in hists[0][0]]

    for hist, label in zip(hists, labels):
        centers = []
        widths = []
        heights = []
        for left, right, content in zip(hist[2][:-1], hist[2][1:], hist[0]):
            centers.append((right + left) / 2)
            widths.append(right - left)
            heights.append(content)

        plt.bar(centers, heights, widths, bottoms, label=label)
        for i, content in enumerate(hist[0]):
            bottoms[i] += content


def hists_to_table(hists, row_labels=(), column_labels=(), format="{:.2f}"):
    table = ['<table class="table table-condensed">']
    if column_labels:
        table.append('<thead><tr>')
        if row_labels:
            table.append('<th></th>')
        table.extend(f'<th>{label}</th>' for label in column_labels)
        table.append('</tr></thead>')
    table.append('<tbody>\n')
    for row_label, (vals, *_) in zip_longest(row_labels, hists):
        table.append('<tr>')
        if row_label:
            table.append(f'<td><strong>{row_label}</strong></td>')
        table.extend(('<td>'+format.format(val)+'</td>') for val in vals)
        table.append('</tr>\n')
    table.append('</tbody></table>')
    return ''.join(table)