import matplotlib.pyplot as plt
import matplotlib.patches as mpatches
import numpy as np
import os

"""This file is part of the Gudhi Library. The Gudhi library
   (Geometric Understanding in Higher Dimensions) is a generic C++
   library for computational topology.

   Author(s):       Vincent Rouvreau, Bertrand Michel

   Copyright (C) 2016 Inria

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
"""

__author__ = "Vincent Rouvreau, Bertrand Michel"
__copyright__ = "Copyright (C) 2016 Inria"
__license__ = "GPL v3"

def __min_birth_max_death(persistence, band=0.):
    """This function returns (min_birth, max_death) from the persistence.

    :param persistence: The persistence to plot.
    :type persistence: list of tuples(dimension, tuple(birth, death)).
    :param band: band
    :type band: float.
    :returns: (float, float) -- (min_birth, max_death).
    """
    # Look for minimum birth date and maximum death date for plot optimisation
    max_death = 0
    min_birth = persistence[0][1][0]
    for interval in reversed(persistence):
        if float(interval[1][1]) != float('inf'):
            if float(interval[1][1]) > max_death:
                max_death = float(interval[1][1])
        if float(interval[1][0]) > max_death:
            max_death = float(interval[1][0])
        if float(interval[1][0]) < min_birth:
            min_birth = float(interval[1][0])
    if band > 0.:
        max_death += band
    return (min_birth, max_death)

"""
Only 13 colors for the palette
"""
palette = ['#ff0000', '#00ff00', '#0000ff', '#00ffff', '#ff00ff', '#ffff00',
           '#000000', '#880000', '#008800', '#000088', '#888800', '#880088',
           '#008888']
 
def plot_persistence_barcode(persistence=[], persistence_file='', alpha=0.6,
        max_barcodes=1000, inf_delta=0.1, legend=False):
    """This function plots the persistence bar code from persistence values list
    or from a :doc:`persistence file <fileformats>`.

    :param persistence: Persistence values list.
    :type persistence: list of tuples(dimension, tuple(birth, death)).
    :param persistence_file: A :doc:`persistence file <fileformats>` style name
        (reset persistence if both are set).
    :type persistence_file: string
    :param alpha: barcode transparency value (0.0 transparent through 1.0 opaque - default is 0.6).
    :type alpha: float.
    :param max_barcodes: number of maximal barcodes to be displayed.
        Set it to 0 to see all, Default value is 1000.
        (persistence will be sorted by life time if max_barcodes is set)
    :type max_barcodes: int.
    :param inf_delta: Infinity is placed at ((max_death - min_birth) x inf_delta).
        A reasonable value is between 0.05 and 0.5 - default is 0.1.
    :type inf_delta: float.
    :returns: A matplotlib object containing horizontal bar plot of persistence
        (launch `show()` method on it to display it).
    """
    if persistence_file is not '':
        if os.path.isfile(persistence_file):
            # Reset persistence
            persistence = []
            diag = read_persistence_intervals_grouped_by_dimension(persistence_file=persistence_file)
            for key in diag.keys():
                for persistence_interval in diag[key]:
                    persistence.append((key, persistence_interval))
        else:
            print("file " + persistence_file + " not found.")
            return None

    if max_barcodes > 0 and max_barcodes < len(persistence):
        # Sort by life time, then takes only the max_plots elements
        persistence = sorted(persistence, key=lambda life_time: life_time[1][1]-life_time[1][0], reverse=True)[:max_barcodes]

    persistence = sorted(persistence, key=lambda birth: birth[1][0])

    (min_birth, max_death) = __min_birth_max_death(persistence)
    ind = 0
    delta = ((max_death - min_birth) * inf_delta)
    # Replace infinity values with max_death + delta for bar code to be more
    # readable
    infinity = max_death + delta
    axis_start = min_birth - delta
    # Draw horizontal bars in loop
    for interval in reversed(persistence):
        if float(interval[1][1]) != float('inf'):
            # Finite death case
            plt.barh(ind, (interval[1][1] - interval[1][0]), height=0.8,
                     left = interval[1][0], alpha=alpha,
                     color = palette[interval[0]],
                     linewidth=0)
        else:
            # Infinite death case for diagram to be nicer
            plt.barh(ind, (infinity - interval[1][0]), height=0.8,
                     left = interval[1][0], alpha=alpha,
                     color = palette[interval[0]],
                     linewidth=0)
        ind = ind + 1

    if legend:
        dimensions = list(set(item[0] for item in persistence))
        plt.legend(handles=[mpatches.Patch(color=palette[dim],
                                           label=str(dim)) for dim in dimensions],
                   loc='lower right')
    plt.title('Persistence barcode')
    # Ends plot on infinity value and starts a little bit before min_birth
    plt.axis([axis_start, infinity, 0, ind])
    return plt

def plot_persistence_diagram(persistence=[], persistence_file='', alpha=0.6,
        band=0., max_plots=1000, inf_delta=0.1, legend=False):
    """This function plots the persistence diagram from persistence values list
    or from a :doc:`persistence file <fileformats>`.

    :param persistence: Persistence values list.
    :type persistence: list of tuples(dimension, tuple(birth, death)).
    :param persistence_file: A :doc:`persistence file <fileformats>` style name
        (reset persistence if both are set).
    :type persistence_file: string
    :param alpha: plot transparency value (0.0 transparent through 1.0 opaque - default is 0.6).
    :type alpha: float.
    :param band: band (not displayed if :math:`\leq` 0. - default is 0.)
    :type band: float.
    :param max_plots: number of maximal plots to be displayed
        Set it to 0 to see all, Default value is 1000.
        (persistence will be sorted by life time if max_plots is set)
    :type max_plots: int.
    :param inf_delta: Infinity is placed at ((max_death - min_birth) x inf_delta).
        A reasonable value is between 0.05 and 0.5 - default is 0.1.
    :type inf_delta: float.
    :returns: A matplotlib object containing diagram plot of persistence
        (launch `show()` method on it to display it).
    """
    if persistence_file is not '':
        if os.path.isfile(persistence_file):
            # Reset persistence
            persistence = []
            diag = read_persistence_intervals_grouped_by_dimension(persistence_file=persistence_file)
            for key in diag.keys():
                for persistence_interval in diag[key]:
                    persistence.append((key, persistence_interval))
        else:
            print("file " + persistence_file + " not found.")
            return None

    if max_plots > 0 and max_plots < len(persistence):
        # Sort by life time, then takes only the max_plots elements
        persistence = sorted(persistence, key=lambda life_time: life_time[1][1]-life_time[1][0], reverse=True)[:max_plots]

    (min_birth, max_death) = __min_birth_max_death(persistence, band)
    ind = 0
    delta = ((max_death - min_birth) * inf_delta)
    # Replace infinity values with max_death + delta for diagram to be more
    # readable
    infinity = max_death + delta
    axis_start = min_birth - delta

    # line display of equation : birth = death
    x = np.linspace(axis_start, infinity, 1000)
    # infinity line and text
    plt.plot(x, x, color='k', linewidth=1.0)
    plt.plot(x, [infinity] * len(x), linewidth=1.0, color='k', alpha=alpha)
    plt.text(axis_start, infinity, r'$\infty$', color='k', alpha=alpha)
    # bootstrap band
    if band > 0.:
        plt.fill_between(x, x, x+band, alpha=alpha, facecolor='red')

    # Draw points in loop
    for interval in reversed(persistence):
        if float(interval[1][1]) != float('inf'):
            # Finite death case
            plt.scatter(interval[1][0], interval[1][1], alpha=alpha,
                        color = palette[interval[0]])
        else:
            # Infinite death case for diagram to be nicer
            plt.scatter(interval[1][0], infinity, alpha=alpha,
                        color = palette[interval[0]])
        ind = ind + 1

    if legend:
        dimensions = list(set(item[0] for item in persistence))
        plt.legend(handles=[mpatches.Patch(color=palette[dim], label=str(dim)) for dim in dimensions])

    plt.title('Persistence diagram')
    plt.xlabel('Birth')
    plt.ylabel('Death')
    # Ends plot on infinity value and starts a little bit before min_birth
    plt.axis([axis_start, infinity, axis_start, infinity + delta])
    return plt