import os
from pathlib import Path
from itertools import chain

import pytest

from .image_support import ImageDifference, run_cargo_cmd

def pytest_assertrepr_compare(op, left, right):
    if isinstance(left, ImageDifference) or isinstance(right, ImageDifference):
        diff = left if isinstance(left, ImageDifference) else right
        return [
            f'Image difference assertion failed.',
            f'    Calculated difference: {diff}',
            f'    Histogram: {diff.histogram}', ]

# store report in node object so tmp_gbr can determine if the test failed.
@pytest.hookimpl(tryfirst=True, hookwrapper=True)
def pytest_runtest_makereport(item, call):
    outcome = yield
    rep = outcome.get_result()
    setattr(item, f'rep_{rep.when}', rep)

fail_dir = Path('gerbonara_test_failures')
def pytest_sessionstart(session):
    if not hasattr(session.config, 'workerinput'): # on worker
        return

    # on coordinator
    for f in chain(fail_dir.glob('*.gbr'), fail_dir.glob('*.png')):
        f.unlink()

    try:
        run_cargo_cmd('resvg', '--help')
    except FileNotFoundError:
        pytest.exit('resvg binary not found, aborting test.', 2)

def pytest_addoption(parser):
    parser.addoption('--kicad-symbol-library', nargs='*', help='Run symbol library tests on given symbol libraries. May be given multiple times.')
    parser.addoption('--kicad-footprint-files', nargs='*', help='Run footprint library tests on given footprint files. May be given multiple times.')

def pytest_generate_tests(metafunc):
    if 'kicad_library_file' in metafunc.fixturenames:
        if not (library_files := metafunc.config.getoption('symbol_library', None)):
            if (lib_dir := os.environ.get('KICAD_SYMBOLS')):
                lib_dir = Path(lib_dir).expanduser()
                if not lib_dir.is_dir():
                    raise ValueError(f'Path "{lib_dir}" given by KICAD_SYMBOLS environment variable does not exist or is not a directory.')
                library_files = list(lib_dir.glob('*.kicad_sym'))
            else:
                raise ValueError('Either --kicad-symbol-library command line parameter or KICAD_SYMBOLS environment variable must be given.')
        metafunc.parametrize('kicad_library_file', library_files, ids=list(map(str, library_files)))

    if 'kicad_mod_file' in metafunc.fixturenames:
        if not (mod_files := metafunc.config.getoption('footprint_files', None)):
            if (lib_dir := os.environ.get('KICAD_FOOTPRINTS')):
                lib_dir = Path(lib_dir).expanduser()
                if not lib_dir.is_dir():
                    raise ValueError(f'Path "{lib_dir}" given by KICAD_FOOTPRINTS environment variable does not exist or is not a directory.')
                mod_files = list(lib_dir.glob('*.pretty/*.kicad_mod'))
            else:
                raise ValueError('Either --kicad-footprint-files command line parameter or KICAD_FOOTPRINTS environment variable must be given.')
        metafunc.parametrize('kicad_mod_file', mod_files, ids=list(map(str, mod_files)))