from __future__ import annotations

import logging
from datetime import date
from pathlib import Path
from typing import Callable

import pytest

from tenbackward.matching import (
    MatchedPost,
    find_anniversary_matches,
    iter_anniversary_paths,
)


SITE_URL = "https://chaospott.de"

_MATCHING_LOGGER = "tenbackward.matching"


def _write_post(root: Path, rel_path: str, *, body: str = "post") -> None:
    full = root / rel_path
    full.parent.mkdir(parents=True, exist_ok=True)
    full.write_text(body, encoding="utf-8")


def _capture_matching_warnings(call: Callable[[], object]) -> list[logging.LogRecord]:
    records: list[logging.LogRecord] = []
    handler = logging.Handler()
    handler.setLevel(logging.WARNING)
    handler.emit = records.append  # type: ignore[assignment]
    logger = logging.getLogger(_MATCHING_LOGGER)
    previous_level = logger.level
    logger.setLevel(logging.WARNING)
    logger.addHandler(handler)
    try:
        call()
    finally:
        logger.removeHandler(handler)
        logger.setLevel(previous_level)
    return records


def _event_names(records: list[logging.LogRecord]) -> list[str]:
    return [getattr(record, "event", None) for record in records]


def test_match_uses_frontmatter_date_and_title(tmp_path: Path) -> None:
    root = tmp_path / "_posts" / "blog"
    _write_post(
        root,
        "2014/2014-08-04-foo.md",
        body="---\ntitle: Foo\ndate: 2014-08-04\n---\nbody\n",
    )

    today = date(2024, 8, 4)
    matches = find_anniversary_matches(root, SITE_URL, today=today)

    assert len(matches) == 1
    match = matches[0]
    assert isinstance(match, MatchedPost)
    assert match.path == "2014/2014-08-04-foo.md"
    assert match.title == "Foo"
    assert match.date == date(2014, 8, 4)
    assert match.url == "https://chaospott.de/2014/08/04/foo/"


def test_match_falls_back_to_filename_when_frontmatter_missing(tmp_path: Path) -> None:
    root = tmp_path / "_posts" / "blog"
    _write_post(root, "2015/2015-03-10-no-frontmatter.md", body="no frontmatter at all\n")
    _write_post(
        root, "2015/2015-03-11-broken-frontmatter.md", body="---\ndate: not-a-date\n: :\n"
    )

    today = date(2025, 3, 10)
    matches: list[MatchedPost] = []
    records = _capture_matching_warnings(
        lambda: matches.extend(find_anniversary_matches(root, SITE_URL, today=today))
    )

    paths = {m.path for m in matches}
    assert "2015/2015-03-10-no-frontmatter.md" in paths
    assert "2015/2015-03-11-broken-frontmatter.md" not in paths

    match = next(m for m in matches if m.path == "2015/2015-03-10-no-frontmatter.md")
    assert match.title == "no-frontmatter"
    assert match.date == date(2015, 3, 10)
    assert match.url == "https://chaospott.de/2015/03/10/no-frontmatter/"


def test_unpublished_post_is_skipped(tmp_path: Path) -> None:
    root = tmp_path / "_posts" / "blog"
    _write_post(
        root,
        "2014/2014-08-04-draft.md",
        body="---\ntitle: Draft\ndate: 2014-08-04\npublished: false\n---\n",
    )

    today = date(2024, 8, 4)
    matches: list[MatchedPost] = []
    records = _capture_matching_warnings(
        lambda: matches.extend(find_anniversary_matches(root, SITE_URL, today=today))
    )

    assert matches == []
    assert _event_names(records) == ["post_unpublished"]


def test_iter_anniversary_paths_yields_only_path(tmp_path: Path) -> None:
    root = tmp_path / "_posts" / "blog"
    _write_post(
        root,
        "2014/2014-08-04-foo.md",
        body="---\ntitle: Foo\ndate: 2014-08-04\n---\n",
    )

    paths = list(iter_anniversary_paths(root, SITE_URL, today=date(2024, 8, 4)))
    assert paths == ["2014/2014-08-04-foo.md"]


@pytest.mark.parametrize(
    "today, source_iso, expected_match",
    [
        # Normal exact match (Mar 1 source, Mar 1 today) -> match
        (date(2025, 3, 1), "2015-03-01", True),
        # Mar 1 source (2016, the day after Feb 29) in a non-leap current year -> no match
        (date(2025, 3, 1), "2016-03-01", False),
        # Feb 29 source in a non-leap current year, today is Mar 1: source year
        # (2016) does not equal target_year (2015), so it does NOT match under
        # the strict year-equality rule.
        (date(2025, 3, 1), "2016-02-29", False),
    ],
)
def test_leap_day_matching(
    tmp_path: Path, today: date, source_iso: str, expected_match: bool
) -> None:
    root = tmp_path / "_posts" / "blog"
    target_year = today.year - 10
    rel = f"{target_year}/{source_iso}-leap.md"
    _write_post(
        root,
        rel,
        body=f"---\ntitle: Leap\ndate: {source_iso}\n---\n",
    )

    matches = find_anniversary_matches(root, SITE_URL, today=today)
    matched_paths = [m.path for m in matches]
    if expected_match:
        assert rel in matched_paths
    else:
        assert rel not in matched_paths


def test_match_uses_datetime_frontmatter_date(tmp_path: Path) -> None:
    root = tmp_path / "_posts" / "blog"
    _write_post(
        root,
        "2014/2014-08-04-with-time.md",
        body="---\ntitle: WithTime\ndate: 2014-08-04T12:30:00\n---\n",
    )

    today = date(2024, 8, 4)
    matches = find_anniversary_matches(root, SITE_URL, today=today)
    assert len(matches) == 1
    assert matches[0].date == date(2014, 8, 4)


def test_match_returns_results_in_deterministic_order(tmp_path: Path) -> None:
    root = tmp_path / "_posts" / "blog"
    for slug, day in [("alpha", 1), ("beta", 2), ("gamma", 3)]:
        _write_post(
            root,
            f"2014/2014-08-0{day}-{slug}.md",
            body=f"---\ntitle: {slug}\ndate: 2014-08-0{day}\n---\n",
        )

    today = date(2024, 8, 2)
    matches = find_anniversary_matches(root, SITE_URL, today=today)
    assert [m.path for m in matches] == ["2014/2014-08-02-beta.md"]


def test_missing_post_root_returns_empty(tmp_path: Path) -> None:
    today = date(2024, 8, 4)
    assert find_anniversary_matches(tmp_path / "does-not-exist", SITE_URL, today=today) == []


def test_invalid_filename_is_skipped(tmp_path: Path) -> None:
    root = tmp_path / "_posts" / "blog"
    _write_post(root, "2014/not-a-date.md", body="---\ntitle: Bad\n---\n")

    today = date(2024, 8, 4)
    matches: list[MatchedPost] = []
    records = _capture_matching_warnings(
        lambda: matches.extend(find_anniversary_matches(root, SITE_URL, today=today))
    )

    assert matches == []
    assert "post_filename_invalid" in _event_names(records)