import numpy as np
from io import BytesIO
import os
import re
import tempfile
import warnings
import xml.parsers.expat

import pytest

import matplotlib as mpl
from matplotlib import dviread
from matplotlib.figure import Figure
import matplotlib.pyplot as plt
from matplotlib.testing.decorators import image_comparison


with warnings.catch_warnings():
    warnings.simplefilter('ignore')
    needs_usetex = pytest.mark.skipif(
        not mpl.checkdep_usetex(True),
        reason="This test needs a TeX installation")


def test_visibility():
    fig, ax = plt.subplots()

    x = np.linspace(0, 4 * np.pi, 50)
    y = np.sin(x)
    yerr = np.ones_like(y)

    a, b, c = ax.errorbar(x, y, yerr=yerr, fmt='ko')
    for artist in b:
        artist.set_visible(False)

    fd = BytesIO()
    fig.savefig(fd, format='svg')

    fd.seek(0)
    buf = fd.read()
    fd.close()

    parser = xml.parsers.expat.ParserCreate()
    parser.Parse(buf)  # this will raise ExpatError if the svg is invalid


@image_comparison(['fill_black_with_alpha.svg'], remove_text=True)
def test_fill_black_with_alpha():
    fig = plt.figure()
    ax = fig.add_subplot(1, 1, 1)
    ax.scatter(x=[0, 0.1, 1], y=[0, 0, 0], c='k', alpha=0.1, s=10000)


@image_comparison(['noscale'], remove_text=True)
def test_noscale():
    X, Y = np.meshgrid(np.arange(-5, 5, 1), np.arange(-5, 5, 1))
    Z = np.sin(Y ** 2)

    fig = plt.figure()
    ax = fig.add_subplot(1, 1, 1)
    ax.imshow(Z, cmap='gray', interpolation='none')


def test_text_urls():
    fig = plt.figure()

    test_url = "http://test_text_urls.matplotlib.org"
    fig.suptitle("test_text_urls", url=test_url)

    fd = BytesIO()
    fig.savefig(fd, format='svg')
    fd.seek(0)
    buf = fd.read().decode()
    fd.close()

    expected = '<a xlink:href="{0}">'.format(test_url)
    assert expected in buf


@image_comparison(['bold_font_output.svg'])
def test_bold_font_output():
    fig = plt.figure()
    ax = fig.add_subplot(1, 1, 1)
    ax.plot(np.arange(10), np.arange(10))
    ax.set_xlabel('nonbold-xlabel')
    ax.set_ylabel('bold-ylabel', fontweight='bold')
    ax.set_title('bold-title', fontweight='bold')


@image_comparison(['bold_font_output_with_none_fonttype.svg'])
def test_bold_font_output_with_none_fonttype():
    plt.rcParams['svg.fonttype'] = 'none'
    fig = plt.figure()
    ax = fig.add_subplot(1, 1, 1)
    ax.plot(np.arange(10), np.arange(10))
    ax.set_xlabel('nonbold-xlabel')
    ax.set_ylabel('bold-ylabel', fontweight='bold')
    ax.set_title('bold-title', fontweight='bold')


@needs_usetex
def test_missing_psfont(monkeypatch):
    """An error is raised if a TeX font lacks a Type-1 equivalent"""

    def psfont(*args, **kwargs):
        return dviread.PsFont(texname='texfont', psname='Some Font',
                              effects=None, encoding=None, filename=None)

    monkeypatch.setattr(dviread.PsfontsMap, '__getitem__', psfont)
    mpl.rc('text', usetex=True)
    fig, ax = plt.subplots()
    ax.text(0.5, 0.5, 'hello')
    with tempfile.TemporaryFile() as tmpfile, pytest.raises(ValueError):
        fig.savefig(tmpfile, format='svg')


# Use Computer Modern Sans Serif, not Helvetica (which has no \textwon).
@pytest.mark.style('default')
@needs_usetex
def test_unicode_won():
    fig = Figure()
    fig.text(.5, .5, r'\textwon', usetex=True)

    with BytesIO() as fd:
        fig.savefig(fd, format='svg')
        buf = fd.getvalue().decode('ascii')

    won_id = 'Computer_Modern_Sans_Serif-142'
    assert re.search(r'<path d=(.|\s)*?id="{0}"/>'.format(won_id), buf)
    assert re.search(r'<use[^/>]*? xlink:href="#{0}"/>'.format(won_id), buf)


def test_svgnone_with_data_coordinates():
    plt.rcParams['svg.fonttype'] = 'none'
    expected = 'Unlikely to appear by chance'

    fig, ax = plt.subplots()
    ax.text(np.datetime64('2019-06-30'), 1, expected)
    ax.set_xlim(np.datetime64('2019-01-01'), np.datetime64('2019-12-31'))
    ax.set_ylim(0, 2)

    with BytesIO() as fd:
        fig.savefig(fd, format='svg')
        fd.seek(0)
        buf = fd.read().decode()

    assert expected in buf
