import io
import os
from pathlib import Path
import sys
import tempfile

import numpy as np
import pytest

from matplotlib import dviread, pyplot as plt, checkdep_usetex, rcParams
from matplotlib.backends.backend_pdf import PdfPages
from matplotlib.testing.compare import compare_images
from matplotlib.testing.decorators import image_comparison


needs_usetex = pytest.mark.skipif(
    not checkdep_usetex(True),
    reason="This test needs a TeX installation")


@image_comparison(['pdf_use14corefonts.pdf'])
def test_use14corefonts():
    rcParams['pdf.use14corefonts'] = True
    rcParams['font.family'] = 'sans-serif'
    rcParams['font.size'] = 8
    rcParams['font.sans-serif'] = ['Helvetica']
    rcParams['pdf.compression'] = 0

    text = '''A three-line text positioned just above a blue line
and containing some French characters and the euro symbol:
"Merci pépé pour les 10 €"'''

    fig = plt.figure()
    ax = fig.add_subplot(1, 1, 1)
    ax.set_title('Test PDF backend with option use14corefonts=True')
    ax.text(0.5, 0.5, text, horizontalalignment='center',
            verticalalignment='bottom',
            fontsize=14)
    ax.axhline(0.5, linewidth=0.5)


def test_type42():
    rcParams['pdf.fonttype'] = 42

    fig = plt.figure()
    ax = fig.add_subplot(111)
    ax.plot([1, 2, 3])
    fig.savefig(io.BytesIO())


def test_multipage_pagecount():
    with PdfPages(io.BytesIO()) as pdf:
        assert pdf.get_pagecount() == 0
        fig = plt.figure()
        ax = fig.add_subplot(111)
        ax.plot([1, 2, 3])
        fig.savefig(pdf, format="pdf")
        assert pdf.get_pagecount() == 1
        pdf.savefig()
        assert pdf.get_pagecount() == 2


def test_multipage_properfinalize():
    pdfio = io.BytesIO()
    with PdfPages(pdfio) as pdf:
        for i in range(10):
            fig = plt.figure()
            ax = fig.add_subplot(111)
            ax.set_title('This is a long title')
            fig.savefig(pdf, format="pdf")
    pdfio.seek(0)
    assert sum(b'startxref' in line for line in pdfio) == 1
    assert sys.getsizeof(pdfio) < 40000


def test_multipage_keep_empty():
    from matplotlib.backends.backend_pdf import PdfPages
    from tempfile import NamedTemporaryFile
    # test empty pdf files
    # test that an empty pdf is left behind with keep_empty=True (default)
    with NamedTemporaryFile(delete=False) as tmp:
        with PdfPages(tmp) as pdf:
            filename = pdf._file.fh.name
        assert os.path.exists(filename)
    os.remove(filename)
    # test if an empty pdf is deleting itself afterwards with keep_empty=False
    with PdfPages(filename, keep_empty=False) as pdf:
        pass
    assert not os.path.exists(filename)
    # test pdf files with content, they should never be deleted
    fig = plt.figure()
    ax = fig.add_subplot(111)
    ax.plot([1, 2, 3])
    # test that a non-empty pdf is left behind with keep_empty=True (default)
    with NamedTemporaryFile(delete=False) as tmp:
        with PdfPages(tmp) as pdf:
            filename = pdf._file.fh.name
            pdf.savefig()
        assert os.path.exists(filename)
    os.remove(filename)
    # test that a non-empty pdf is left behind with keep_empty=False
    with NamedTemporaryFile(delete=False) as tmp:
        with PdfPages(tmp, keep_empty=False) as pdf:
            filename = pdf._file.fh.name
            pdf.savefig()
        assert os.path.exists(filename)
    os.remove(filename)


def test_composite_image():
    # Test that figures can be saved with and without combining multiple images
    # (on a single set of axes) into a single composite image.
    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.set_xlim(0, 3)
    ax.imshow(Z, extent=[0, 1, 0, 1])
    ax.imshow(Z[::-1], extent=[2, 3, 0, 1])
    plt.rcParams['image.composite_image'] = True
    with PdfPages(io.BytesIO()) as pdf:
        fig.savefig(pdf, format="pdf")
        assert len(pdf._file._images) == 1
    plt.rcParams['image.composite_image'] = False
    with PdfPages(io.BytesIO()) as pdf:
        fig.savefig(pdf, format="pdf")
        assert len(pdf._file._images) == 2


def test_pdfpages_fspath():
    with PdfPages(Path(os.devnull)) as pdf:
        pdf.savefig(plt.figure())


@image_comparison(['hatching_legend.pdf'])
def test_hatching_legend():
    """Test for correct hatching on patches in legend"""
    fig = plt.figure(figsize=(1, 2))

    a = plt.Rectangle([0, 0], 0, 0, facecolor="green", hatch="XXXX")
    b = plt.Rectangle([0, 0], 0, 0, facecolor="blue", hatch="XXXX")

    fig.legend([a, b, a, b], ["", "", "", ""])


@image_comparison(['grayscale_alpha.pdf'])
def test_grayscale_alpha():
    """Masking images with NaN did not work for grayscale images"""
    x, y = np.ogrid[-2:2:.1, -2:2:.1]
    dd = np.exp(-(x**2 + y**2))
    dd[dd < .1] = np.nan
    fig, ax = plt.subplots()
    ax.imshow(dd, interpolation='none', cmap='gray_r')
    ax.set_xticks([])
    ax.set_yticks([])


# This tests tends to hit a TeX cache lock on AppVeyor.
@pytest.mark.flaky(reruns=3)
@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)
    rcParams['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='pdf')


@pytest.mark.style('default')
def test_pdf_savefig_when_color_is_none(tmpdir):
    fig, ax = plt.subplots()
    plt.axis('off')
    ax.plot(np.sin(np.linspace(-5, 5, 100)), 'v', c='none')
    actual_image = tmpdir.join('figure.pdf')
    expected_image = tmpdir.join('figure.eps')
    fig.savefig(str(actual_image), format='pdf')
    fig.savefig(str(expected_image), format='eps')
    result = compare_images(str(actual_image), str(expected_image), 0)
    assert result is None


@needs_usetex
def test_failing_latex(tmpdir):
    """Test failing latex subprocess call"""
    path = str(tmpdir.join("tmpoutput.pdf"))

    rcParams['text.usetex'] = True

    # This fails with "Double subscript"
    plt.xlabel("$22_2_2$")
    with pytest.raises(RuntimeError):
        plt.savefig(path)


def test_empty_rasterized():
    # Check that empty figures that are rasterised save to pdf files fine
    fig, ax = plt.subplots()
    ax.plot([], [], rasterized=True)
    fig.savefig(io.BytesIO(), format="pdf")
