import glob
import os
import sys
from contextlib import contextmanager
from pathlib import Path

from git import Repo
from mypy import build
from mypy.main import process_options

DJANGO_BRANCH = 'stable/2.1.x'
DJANGO_COMMIT_SHA = '03219b5f709dcd5b0bfacd963508625557ec1ef0'
IGNORED_ERROR_PATTERNS = [
    'Need type annotation for',
    'already defined on',
    'Cannot assign to a',
    'cannot perform relative import',
    'broken_app',
    'LazySettings',
    'Cannot infer type of lambda',
    'Incompatible types in assignment (expression has type "Callable[',
    '"Callable[[Any], Any]" has no attribute',
    '"Callable[[Any, Any], Any]" has no attribute',
    'Invalid value for a to= parameter',
    '"HttpResponseBase" has no attribute "user"'
]
TESTS_DIRS = [
    'absolute_url_overrides',
    # 'admin_*'
]


@contextmanager
def cd(path):
    """Context manager to temporarily change working directories"""
    if not path:
        return
    prev_cwd = Path.cwd().as_posix()
    if isinstance(path, Path):
        path = path.as_posix()
    os.chdir(str(path))
    try:
        yield
    finally:
        os.chdir(prev_cwd)


def is_ignored(line: str) -> bool:
    for pattern in IGNORED_ERROR_PATTERNS:
        if pattern in line:
            return True
    return False


def check_with_mypy(abs_path: Path, config_file_path: Path) -> int:
    error_happened = False
    with cd(abs_path):
        sources, options = process_options(['--config-file', str(config_file_path), str(abs_path)])
        res = build.build(sources, options)
        for error_line in res.errors:
            if not is_ignored(error_line):
                error_happened = True
                print(error_line)
    return int(error_happened)


if __name__ == '__main__':
    project_directory = Path(__file__).parent.parent
    mypy_config_file = (project_directory / 'scripts' / 'mypy.ini').absolute()
    repo_directory = project_directory / 'django-sources'
    tests_root = repo_directory / 'tests'
    global_rc = 0

    # clone Django repository, if it does not exist
    if not repo_directory.exists():
        repo = Repo.clone_from('https://github.com/django/django.git', repo_directory)
    else:
        repo = Repo(repo_directory)
        repo.remote().pull(DJANGO_COMMIT_SHA)

    branch = repo.heads[DJANGO_BRANCH]
    branch.checkout()
    assert repo.active_branch.name == DJANGO_BRANCH
    assert repo.active_branch.commit.hexsha == DJANGO_COMMIT_SHA

    for dirname in TESTS_DIRS:
        paths = glob.glob(str(tests_root / dirname))
        for path in paths:
            abs_path = (project_directory / path).absolute()

            print(f'Checking {abs_path.as_uri()}')
            rc = check_with_mypy(abs_path, mypy_config_file)
            if rc != 0:
                global_rc = 1

    sys.exit(rc)