# -*- encoding: utf-8 -*-
from __future__ import (absolute_import, division, print_function,
                        unicode_literals)

import six

import os
import shutil

import numpy as np
import nose
from nose.plugins.skip import SkipTest

import matplotlib as mpl
import matplotlib.pyplot as plt
from matplotlib.compat import subprocess
from matplotlib.testing.compare import compare_images, ImageComparisonFailure
from matplotlib.testing.decorators import _image_directories


baseline_dir, result_dir = _image_directories(lambda: 'dummy func')


def check_for(texsystem):
    header = """
    \\documentclass{minimal}
    \\usepackage{pgf}
    \\begin{document}
    \\typeout{pgfversion=\\pgfversion}
    \\makeatletter
    \\@@end
    """
    try:
        latex = subprocess.Popen(["xelatex", "-halt-on-error"],
                                 stdin=subprocess.PIPE,
                                 stdout=subprocess.PIPE)
        stdout, stderr = latex.communicate(header.encode("utf8"))
    except OSError:
        return False

    return latex.returncode == 0


def switch_backend(backend):

    def switch_backend_decorator(func):
        def backend_switcher(*args, **kwargs):
            try:
                prev_backend = mpl.get_backend()
                mpl.rcdefaults()
                plt.switch_backend(backend)
                result = func(*args, **kwargs)
            finally:
                plt.switch_backend(prev_backend)
            return result

        return nose.tools.make_decorator(func)(backend_switcher)
    return switch_backend_decorator


def compare_figure(fname, savefig_kwargs={}):
    actual = os.path.join(result_dir, fname)
    plt.savefig(actual, **savefig_kwargs)

    expected = os.path.join(result_dir, "expected_%s" % fname)
    shutil.copyfile(os.path.join(baseline_dir, fname), expected)
    err = compare_images(expected, actual, tol=14)
    if err:
        raise ImageComparisonFailure('images not close: %s vs. '
                                     '%s' % (actual, expected))


def create_figure():
    plt.figure()
    x = np.linspace(0, 1, 15)
    plt.plot(x, x ** 2, "b-")
    plt.fill_between([0., .4], [.4, 0.], hatch='//', facecolor="lightgray",
                     edgecolor="red")
    plt.plot(x, 1 - x**2, "g>")
    plt.plot([0.9], [0.5], "ro", markersize=3)
    plt.text(0.9, 0.5, 'unicode (ü, °, µ) and math ($\\mu_i = x_i^2$)',
             ha='right', fontsize=20)
    plt.ylabel('sans-serif, blue, $\\frac{\\sqrt{x}}{y^2}$..',
               family='sans-serif', color='blue')


# test compiling a figure to pdf with xelatex
@switch_backend('pgf')
def test_xelatex():
    if not check_for('xelatex'):
        raise SkipTest('xelatex + pgf is required')

    rc_xelatex = {'font.family': 'serif',
                  'pgf.rcfonts': False}
    mpl.rcParams.update(rc_xelatex)
    create_figure()
    compare_figure('pgf_xelatex.pdf')


# test compiling a figure to pdf with pdflatex
@switch_backend('pgf')
def test_pdflatex():
    if not check_for('pdflatex'):
        raise SkipTest('pdflatex + pgf is required')

    rc_pdflatex = {'font.family': 'serif',
                   'pgf.rcfonts': False,
                   'pgf.texsystem': 'pdflatex',
                   'pgf.preamble': ['\\usepackage[utf8x]{inputenc}',
                                    '\\usepackage[T1]{fontenc}']}
    mpl.rcParams.update(rc_pdflatex)
    create_figure()
    compare_figure('pgf_pdflatex.pdf')


# test updating the rc parameters for each figure
@switch_backend('pgf')
def test_rcupdate():
    if not check_for('xelatex') or not check_for('pdflatex'):
        raise SkipTest('xelatex and pdflatex + pgf required')

    rc_sets = []
    rc_sets.append({'font.family': 'sans-serif',
                    'font.size': 30,
                    'figure.subplot.left': .2,
                    'lines.markersize': 10,
                    'pgf.rcfonts': False,
                    'pgf.texsystem': 'xelatex'})
    rc_sets.append({'font.family': 'monospace',
                    'font.size': 10,
                    'figure.subplot.left': .1,
                    'lines.markersize': 20,
                    'pgf.rcfonts': False,
                    'pgf.texsystem': 'pdflatex',
                    'pgf.preamble': ['\\usepackage[utf8x]{inputenc}',
                                     '\\usepackage[T1]{fontenc}',
                                     '\\usepackage{sfmath}']})

    for i, rc_set in enumerate(rc_sets):
        mpl.rcParams.update(rc_set)
        create_figure()
        compare_figure('pgf_rcupdate%d.pdf' % (i + 1))


# test backend-side clipping, since large numbers are not supported by TeX
@switch_backend('pgf')
def test_pathclip():
    if not check_for('xelatex'):
        raise SkipTest('xelatex + pgf is required')

    rc_xelatex = {'font.family': 'serif',
                  'pgf.rcfonts': False}
    mpl.rcParams.update(rc_xelatex)

    plt.figure()
    plt.plot([0., 1e100], [0., 1e100])
    plt.xlim(0, 1)
    plt.ylim(0, 1)
    # this test passes if compiling/saving to pdf works (no image comparison)
    plt.savefig(os.path.join(result_dir, "pgf_pathclip.pdf"))


# test mixed mode rendering
@switch_backend('pgf')
def test_mixedmode():
    if not check_for('xelatex'):
        raise SkipTest('xelatex + pgf is required')

    rc_xelatex = {'font.family': 'serif',
                  'pgf.rcfonts': False}
    mpl.rcParams.update(rc_xelatex)

    Y, X = np.ogrid[-1:1:40j, -1:1:40j]
    plt.figure()
    plt.pcolor(X**2 + Y**2).set_rasterized(True)
    compare_figure('pgf_mixedmode.pdf')


# test bbox_inches clipping
@switch_backend('pgf')
def test_bbox_inches():
    if not check_for('xelatex'):
        raise SkipTest('xelatex + pgf is required')

    rc_xelatex = {'font.family': 'serif',
                  'pgf.rcfonts': False}
    mpl.rcParams.update(rc_xelatex)

    Y, X = np.ogrid[-1:1:40j, -1:1:40j]
    fig = plt.figure()
    ax1 = fig.add_subplot(121)
    ax1.plot(range(5))
    ax2 = fig.add_subplot(122)
    ax2.plot(range(5))
    plt.tight_layout()

    bbox = ax1.get_window_extent().transformed(fig.dpi_scale_trans.inverted())
    compare_figure('pgf_bbox_inches.pdf', savefig_kwargs={'bbox_inches': bbox})


if __name__ == '__main__':
    import nose
    nose.runmodule(argv=['-s', '--with-doctest'], exit=False)
