from io import BytesIO, StringIO
import multiprocessing
import os
from pathlib import Path
import shutil
import subprocess
import sys
import warnings

import numpy as np
import pytest

from matplotlib.font_manager import (
    findfont, findSystemFonts, FontProperties, fontManager, json_dump,
    json_load, get_font, is_opentype_cff_font, MSUserFontDirectories,
    _get_fontconfig_fonts)
from matplotlib import pyplot as plt, rc_context

has_fclist = shutil.which('fc-list') is not None


def test_font_priority():
    with rc_context(rc={
            'font.sans-serif':
            ['cmmi10', 'Bitstream Vera Sans']}):
        font = findfont(FontProperties(family=["sans-serif"]))
    assert Path(font).name == 'cmmi10.ttf'

    # Smoketest get_charmap, which isn't used internally anymore
    font = get_font(font)
    cmap = font.get_charmap()
    assert len(cmap) == 131
    assert cmap[8729] == 30


def test_score_weight():
    assert 0 == fontManager.score_weight("regular", "regular")
    assert 0 == fontManager.score_weight("bold", "bold")
    assert (0 < fontManager.score_weight(400, 400) <
            fontManager.score_weight("normal", "bold"))
    assert (0 < fontManager.score_weight("normal", "regular") <
            fontManager.score_weight("normal", "bold"))
    assert (fontManager.score_weight("normal", "regular") ==
            fontManager.score_weight(400, 400))


def test_json_serialization(tmpdir):
    # Can't open a NamedTemporaryFile twice on Windows, so use a temporary
    # directory instead.
    path = Path(tmpdir, "fontlist.json")
    json_dump(fontManager, path)
    copy = json_load(path)
    with warnings.catch_warnings():
        warnings.filterwarnings('ignore', 'findfont: Font family.*not found')
        for prop in ({'family': 'STIXGeneral'},
                     {'family': 'Bitstream Vera Sans', 'weight': 700},
                     {'family': 'no such font family'}):
            fp = FontProperties(**prop)
            assert (fontManager.findfont(fp, rebuild_if_missing=False) ==
                    copy.findfont(fp, rebuild_if_missing=False))


def test_otf():
    fname = '/usr/share/fonts/opentype/freefont/FreeMono.otf'
    if Path(fname).exists():
        assert is_opentype_cff_font(fname)
    for f in fontManager.ttflist:
        if 'otf' in f.fname:
            with open(f.fname, 'rb') as fd:
                res = fd.read(4) == b'OTTO'
            assert res == is_opentype_cff_font(f.fname)


@pytest.mark.skipif(not has_fclist, reason='no fontconfig installed')
def test_get_fontconfig_fonts():
    assert len(_get_fontconfig_fonts()) > 1


@pytest.mark.parametrize('factor', [2, 4, 6, 8])
def test_hinting_factor(factor):
    font = findfont(FontProperties(family=["sans-serif"]))

    font1 = get_font(font, hinting_factor=1)
    font1.clear()
    font1.set_size(12, 100)
    font1.set_text('abc')
    expected = font1.get_width_height()

    hinted_font = get_font(font, hinting_factor=factor)
    hinted_font.clear()
    hinted_font.set_size(12, 100)
    hinted_font.set_text('abc')
    # Check that hinting only changes text layout by a small (10%) amount.
    np.testing.assert_allclose(hinted_font.get_width_height(), expected,
                               rtol=0.1)


def test_utf16m_sfnt():
    try:
        # seguisbi = Microsoft Segoe UI Semibold
        entry = next(entry for entry in fontManager.ttflist
                     if Path(entry.fname).name == "seguisbi.ttf")
    except StopIteration:
        pytest.skip("Couldn't find font to test against.")
    else:
        # Check that we successfully read "semibold" from the font's sfnt table
        # and set its weight accordingly.
        assert entry.weight == 600


def test_find_ttc():
    fp = FontProperties(family=["WenQuanYi Zen Hei"])
    if Path(findfont(fp)).name != "wqy-zenhei.ttc":
        pytest.skip("Font may be missing")

    fig, ax = plt.subplots()
    ax.text(.5, .5, "\N{KANGXI RADICAL DRAGON}", fontproperties=fp)
    for fmt in ["raw", "svg", "pdf", "ps"]:
        fig.savefig(BytesIO(), format=fmt)


def test_find_invalid(tmpdir):
    tmp_path = Path(tmpdir)

    with pytest.raises(FileNotFoundError):
        get_font(tmp_path / 'non-existent-font-name.ttf')

    with pytest.raises(FileNotFoundError):
        get_font(str(tmp_path / 'non-existent-font-name.ttf'))

    with pytest.raises(FileNotFoundError):
        get_font(bytes(tmp_path / 'non-existent-font-name.ttf'))

    # Not really public, but get_font doesn't expose non-filename constructor.
    from matplotlib.ft2font import FT2Font
    with pytest.raises(TypeError, match='path or binary-mode file'):
        FT2Font(StringIO())


@pytest.mark.skipif(sys.platform != 'linux', reason='Linux only')
def test_user_fonts_linux(tmpdir, monkeypatch):
    font_test_file = 'mpltest.ttf'

    # Precondition: the test font should not be available
    fonts = findSystemFonts()
    if any(font_test_file in font for font in fonts):
        pytest.skip(f'{font_test_file} already exists in system fonts')

    # Prepare a temporary user font directory
    user_fonts_dir = tmpdir.join('fonts')
    user_fonts_dir.ensure(dir=True)
    shutil.copyfile(Path(__file__).parent / font_test_file,
                    user_fonts_dir.join(font_test_file))

    with monkeypatch.context() as m:
        m.setenv('XDG_DATA_HOME', str(tmpdir))
        _get_fontconfig_fonts.cache_clear()
        # Now, the font should be available
        fonts = findSystemFonts()
        assert any(font_test_file in font for font in fonts)

    # Make sure the temporary directory is no longer cached.
    _get_fontconfig_fonts.cache_clear()


@pytest.mark.skipif(sys.platform != 'win32', reason='Windows only')
def test_user_fonts_win32():
    if not (os.environ.get('APPVEYOR') or os.environ.get('TF_BUILD')):
        pytest.xfail("This test should only run on CI (appveyor or azure) "
                     "as the developer's font directory should remain "
                     "unchanged.")

    font_test_file = 'mpltest.ttf'

    # Precondition: the test font should not be available
    fonts = findSystemFonts()
    if any(font_test_file in font for font in fonts):
        pytest.skip(f'{font_test_file} already exists in system fonts')

    user_fonts_dir = MSUserFontDirectories[0]

    # Make sure that the user font directory exists (this is probably not the
    # case on Windows versions < 1809)
    os.makedirs(user_fonts_dir)

    # Copy the test font to the user font directory
    shutil.copy(Path(__file__).parent / font_test_file, user_fonts_dir)

    # Now, the font should be available
    fonts = findSystemFonts()
    assert any(font_test_file in font for font in fonts)


def _model_handler(_):
    fig, ax = plt.subplots()
    fig.savefig(BytesIO(), format="pdf")
    plt.close()


@pytest.mark.skipif(not hasattr(os, "register_at_fork"),
                    reason="Cannot register at_fork handlers")
def test_fork():
    _model_handler(0)  # Make sure the font cache is filled.
    ctx = multiprocessing.get_context("fork")
    with ctx.Pool(processes=2) as pool:
        pool.map(_model_handler, range(2))


def test_missing_family(caplog):
    plt.rcParams["font.sans-serif"] = ["this-font-does-not-exist"]
    with caplog.at_level("WARNING"):
        findfont("sans")
    assert [rec.getMessage() for rec in caplog.records] == [
        "findfont: Font family ['sans'] not found. "
        "Falling back to DejaVu Sans.",
        "findfont: Generic family 'sans' not found because none of the "
        "following families were found: this-font-does-not-exist",
    ]


def _test_threading():
    import threading
    from matplotlib.ft2font import LOAD_NO_HINTING
    import matplotlib.font_manager as fm

    N = 10
    b = threading.Barrier(N)

    def bad_idea(n):
        b.wait()
        for j in range(100):
            font = fm.get_font(fm.findfont("DejaVu Sans"))
            font.set_text(str(n), 0.0, flags=LOAD_NO_HINTING)

    threads = [
        threading.Thread(target=bad_idea, name=f"bad_thread_{j}", args=(j,))
        for j in range(N)
    ]

    for t in threads:
        t.start()

    for t in threads:
        t.join()


def test_fontcache_thread_safe():
    pytest.importorskip('threading')
    import inspect

    proc = subprocess.run(
        [sys.executable, "-c",
         inspect.getsource(_test_threading) + '\n_test_threading()']
    )
    if proc.returncode:
        pytest.fail("The subprocess returned with non-zero exit status "
                    f"{proc.returncode}.")
