"""
The reported symptom, end to end: one library shared by two groups.

`test_search_source_merge.py` holds the merging rules in isolation. This holds
the thing an operator actually saw — a node hosting two groups that were given
the same video directory, and a Search view showing every film as two poster
cards and every episode twice inside a show.

Three pieces have to agree for that to come out right, and each lives in a
different file:

  * the application's own grouping (`groupVideoEntries`, `groupMusicEntries`,
    `groupPhotoAlbums`) turns entries into films, shows, albums;
  * `videoUnits` / `musicUnits` / `photoUnits` (search-page.js) turn those into
    merge units;
  * `mergeUnitEntries` (source-merge.js) folds them on the content hash.

All of them are read out of their real sources here rather than restated. Each
pipeline is assembled the way `search-page.js` assembles it, and the result is
passed through the grouping a second time — which is what the application does
with it — so what this counts is what the grid renders.

`t()` is stubbed to return its key: `groupMusicEntries` uses it for the two
placeholder album names, and a string is not what is under test here.

See docs/MESHBAY_DESIGN.md §9.11.
"""

import json
import re
import shutil
import subprocess
from pathlib import Path

import pytest

STATIC = Path(__file__).resolve().parents[1] / "src" / "meshbay_hub" / "static"
VIDEO_APP = STATIC / "video-app.js"
MUSIC_APP = STATIC / "music-app.js"
PHOTOS_APP = STATIC / "photos-app.js"
SEARCH_PAGE = STATIC / "search-page.js"
MERGE = STATIC / "source-merge.js"

pytestmark = pytest.mark.skipif(
    shutil.which("node") is None or not MERGE.exists(),
    reason="node or the SPA sources are not available")

EXPORT = re.compile(r"^export \{[^}]*\};?\s*$", re.M)


def _block(path, header):
    """One top-level `function name(...) {` ... `}` read out of a module."""
    src = path.read_text()
    m = re.search(r"^" + re.escape(header) + r".*?^\}", src, re.M | re.S)
    assert m, (
        f"{header} is no longer where this test reads it from in {path.name} — "
        "the Search view's de-duplication is untested until this is fixed")
    return m.group(0)


def _const(name):
    m = re.search(r"^const " + re.escape(name) + r" = .*?;$",
                  SEARCH_PAGE.read_text(), re.M)
    assert m, f"{name} moved — the search-page units cannot be lifted"
    return m.group(0)


@pytest.fixture(scope="module")
def pipeline():
    """Everything the three views need, in one script."""
    return "\n".join([
        "const t = (k) => k;",
        EXPORT.sub("", MERGE.read_text()),
        _block(VIDEO_APP, "function underVideoRoot(entry, directories) {"),
        _block(VIDEO_APP, "function buildSeasons(episodes) {"),
        _block(VIDEO_APP, "function groupVideoEntries(entries, videoDirectories) {"),
        _block(MUSIC_APP, "function foldKey(s) {"),
        _block(MUSIC_APP, "function underAudioRoot(entry, directories) {"),
        _block(MUSIC_APP, "function groupMusicEntries(entries, musicDirectories) {"),
        _block(PHOTOS_APP, "function underAnyPhotoRoot(entry, photoRoots) {"),
        _block(PHOTOS_APP, "function groupPhotoAlbums(entries, photoRoots) {"),
        _const("SEARCH_VIDEO_ROOT"),
        _const("SEARCH_AUDIO_ROOT"),
        _const("SEARCH_PHOTO_ROOTS"),
        _block(SEARCH_PAGE, "function videoUnits(entries) {"),
        _block(SEARCH_PAGE, "function musicUnits(entries) {"),
        _block(SEARCH_PAGE, "function photoUnits(entries) {"),
    ])


def _node(tmp_path, pipeline, body):
    script = tmp_path / "case.js"
    script.write_text(f"{pipeline}\n{body}\n")
    out = subprocess.run(
        ["node", str(script)], capture_output=True, text=True, timeout=30)
    assert out.returncode == 0, out.stderr
    return json.loads(out.stdout)


def _grid(tmp_path, pipeline, entries, salt="reader", local=()):
    """What the poster grid ends up with, after the merge and VideoApp's own
    regrouping."""
    body = f"""
      const raw = {json.dumps(entries)};
      const local = new Set({json.dumps(list(local))});
      const merged = mergeUnitEntries(videoUnits(raw), {{
        salt: {json.dumps(salt)},
        isLocal: (g) => local.has(g),
      }});
      const {{ movies, shows }} = groupVideoEntries(merged, [SEARCH_VIDEO_ROOT]);
      console.log(JSON.stringify({{
        movies: movies.map((e) => ({{
          id: e.id, title: e.display_title || e.name, groupId: e.groupId,
          sources: e._sources.length,
        }})),
        shows: shows.map((s) => ({{
          title: s.title,
          groups: [...new Set(s.episodes.map((e) => e.groupId))].sort(),
          seasons: s.seasons.map((x) => ({{
            season: x.season,
            episodes: x.episodes.map((e) => `S${{e.season}}E${{e.episode}}`),
          }})),
        }})),
      }}));
    """
    return _node(tmp_path, pipeline, body)


def _albums(tmp_path, pipeline, entries, salt="reader", local=()):
    """What the album grid ends up with, after the merge and MusicApp's own
    regrouping."""
    body = f"""
      const raw = {json.dumps(entries)};
      const local = new Set({json.dumps(list(local))});
      const merged = mergeUnitEntries(musicUnits(raw), {{
        salt: {json.dumps(salt)},
        isLocal: (g) => local.has(g),
      }});
      const {{ albums, tracks }} = groupMusicEntries(merged, [SEARCH_AUDIO_ROOT]);
      console.log(JSON.stringify({{
        albums: albums.map((a) => ({{
          artist: a.artist, album: a.album,
          groups: [...new Set(a.tracks.map((e) => e.groupId))].sort(),
          tracks: a.tracks.map((e) => e.name),
        }})),
        loose: tracks.map((e) => e.name),
      }}));
    """
    return _node(tmp_path, pipeline, body)


def _photo_albums(tmp_path, pipeline, entries, salt="reader", local=()):
    """What the photo album grid ends up with, after the merge and PhotosApp's
    own regrouping."""
    body = f"""
      const raw = {json.dumps(entries)};
      const local = new Set({json.dumps(list(local))});
      const merged = mergeUnitEntries(photoUnits(raw), {{
        salt: {json.dumps(salt)},
        isLocal: (g) => local.has(g),
      }});
      console.log(JSON.stringify(
        groupPhotoAlbums(merged, SEARCH_PHOTO_ROOTS).map((a) => ({{
          dir: a.dir,
          groups: [...new Set(a.photos.map((e) => e.groupId))].sort(),
          photos: a.photos.map((e) => e.name),
        }}))));
    """
    return _node(tmp_path, pipeline, body)


# The shape of one shared library: a film, and a two-season show. Invented
# titles — the real one this was found against is nobody's business here.
def _library(group):
    """`path` is already prefixed the way search-page.js prefixes it."""
    def entry(file_id, name, **kw):
        return {
            "id": file_id, "name": name, "type": "video",
            "path": "__search__/shows", "size": 1,
            "groupId": group, "groupName": group.upper(), "groupOwner": "someone",
            "_tRef": f"t:{group}", "_gRef": f"g:{group}", "_connGen": 1,
            **kw,
        }
    files = [entry("film1", "a-film.mkv", display_title="Some Film")]
    for season in (1, 2):
        for ep in (1, 2, 3):
            files.append(entry(
                f"s{season}e{ep}", f"show.s0{season}e0{ep}.mkv",
                display_title="Some Saga", season=season, episode=ep))
    return files


def test_a_shared_library_is_listed_once(tmp_path, pipeline):
    """
    The bug as reported: two groups, one directory, everything twice.
    """
    both = _library("demo35") + _library("media")
    grid = _grid(tmp_path, pipeline, both)

    assert [m["title"] for m in grid["movies"]] == ["Some Film"]
    assert grid["movies"][0]["sources"] == 2

    assert len(grid["shows"]) == 1
    show = grid["shows"][0]
    assert [s["season"] for s in show["seasons"]] == [1, 2]
    for season in show["seasons"]:
        assert season["episodes"] == [
            f"S{season['season']}E{n}" for n in (1, 2, 3)], (
            "an episode is listed more than once — this is the reported bug, "
            "in the season list under the synopsis")


def test_a_show_streams_from_one_source(tmp_path, pipeline):
    """A season split across two nodes would open two connections and two
    metadata lookups for one show."""
    both = _library("demo35") + _library("media")
    show = _grid(tmp_path, pipeline, both)["shows"][0]
    assert len(show["groups"]) == 1


def test_the_operators_own_node_serves_it(tmp_path, pipeline):
    """Both groups are on the operator's node in the reported case; when only
    one is, that one is the source."""
    both = _library("remote") + _library("mine")
    grid = _grid(tmp_path, pipeline, both, local=["mine"])
    assert grid["movies"][0]["groupId"] == "mine"
    assert grid["shows"][0]["groups"] == ["mine"]


def test_one_group_is_unchanged(tmp_path, pipeline):
    """The overwhelmingly common case: nothing to merge, nothing different."""
    grid = _grid(tmp_path, pipeline, _library("solo"))
    assert [m["title"] for m in grid["movies"]] == ["Some Film"]
    assert grid["movies"][0]["sources"] == 1
    assert grid["movies"][0]["groupId"] == "solo"
    show = grid["shows"][0]
    assert show["groups"] == ["solo"]
    assert sum(len(s["episodes"]) for s in show["seasons"]) == 6


def test_an_episode_only_one_group_has_is_kept(tmp_path, pipeline):
    """
    Merging must never subtract. A group holding one extra episode contributes
    it, whichever source the show settled on.
    """
    extra = _library("media")
    extra.append({
        "id": "s2e4", "name": "show.s02e04.mkv", "type": "video",
        "path": "__search__/shows", "size": 1,
        "groupId": "media", "groupName": "MEDIA", "groupOwner": "someone",
        "display_title": "Some Saga", "season": 2, "episode": 4,
    })
    grid = _grid(tmp_path, pipeline, _library("demo35") + extra)
    season2 = [s for s in grid["shows"][0]["seasons"] if s["season"] == 2][0]
    assert season2["episodes"] == ["S2E1", "S2E2", "S2E3", "S2E4"]


# ── Music ────────────────────────────────────────────────────────────────────

def _record(group, tracks=5):
    """One album, tagged, under the search audio root."""
    return [{
        "id": f"t{n}", "name": f"{n:02d}-track.flac", "type": "audio",
        "path": "__search__/music/some-band/a-record", "size": 1,
        "artist": "Some Band", "album": "A Record", "track_no": n,
        "groupId": group, "groupName": group.upper(), "groupOwner": "someone",
        "_tRef": f"t:{group}", "_gRef": f"g:{group}", "_connGen": 1,
    } for n in range(1, tracks + 1)]


def test_an_album_shared_by_two_groups_lists_each_track_once(tmp_path, pipeline):
    grid = _albums(tmp_path, pipeline, _record("demo35") + _record("media"))
    assert len(grid["albums"]) == 1
    album = grid["albums"][0]
    assert len(album["tracks"]) == 5, (
        "a track is listed more than once — the same bug as the Videos view, "
        "inside an album")
    assert album["groups"] == ["demo35"] or album["groups"] == ["media"]


def test_one_group_of_music_is_unchanged(tmp_path, pipeline):
    grid = _albums(tmp_path, pipeline, _record("solo"))
    assert len(grid["albums"]) == 1
    assert len(grid["albums"][0]["tracks"]) == 5
    assert grid["albums"][0]["groups"] == ["solo"]


def test_a_differently_cased_tag_does_not_split_the_unit(tmp_path, pipeline):
    """
    `groupMusicEntries` folds case for grouping but keeps the first-seen
    spelling for display, and which group is seen first is whichever index
    arrived first. `musicUnits` keys on the folded form for exactly that
    reason — on the display strings, the chosen source could change between
    page loads.
    """
    other = _record("media")
    for track in other:
        track["artist"] = "SOME BAND"
        track["album"] = "a record"
    grid = _albums(tmp_path, pipeline, _record("demo35") + other)
    assert len(grid["albums"]) == 1
    assert len(grid["albums"][0]["tracks"]) == 5


def test_a_track_only_one_group_has_is_kept(tmp_path, pipeline):
    extra = _record("media")
    extra.append({
        "id": "t9", "name": "09-bonus.flac", "type": "audio",
        "path": "__search__/music/some-band/a-record", "size": 1,
        "artist": "Some Band", "album": "A Record", "track_no": 9,
        "groupId": "media", "groupName": "MEDIA", "groupOwner": "someone",
    })
    grid = _albums(tmp_path, pipeline, _record("demo35") + extra)
    assert len(grid["albums"][0]["tracks"]) == 6


def test_an_untagged_track_is_its_own_unit(tmp_path, pipeline):
    """A track with no artist at all never reaches an album bucket, so it has
    to be a unit of its own or it would be dropped from the merge entirely."""
    loose = [{
        "id": "x1", "name": "unknown.mp3", "type": "audio",
        "path": "__search__/music", "size": 1,
        "groupId": g, "groupName": g.upper(),
    } for g in ("demo35", "media")]
    grid = _albums(tmp_path, pipeline, _record("demo35") + loose)
    assert grid["loose"] == ["unknown.mp3"]


# ── Photos ───────────────────────────────────────────────────────────────────

def _photos(group, root="pics", album="a-trip", n=4):
    return [{
        "id": f"p{i}", "name": f"IMG_{i:04d}.jpg", "type": "image",
        "path": f"__search_photos__/{root}/{album}", "size": 1,
        "groupId": group, "groupName": group.upper(), "groupOwner": "someone",
        "_tRef": f"t:{group}", "_gRef": f"g:{group}", "_connGen": 1,
    } for i in range(1, n + 1)]


def test_a_photo_album_shared_by_two_groups_shows_each_photo_once(tmp_path, pipeline):
    albums = _photo_albums(tmp_path, pipeline, _photos("demo35") + _photos("media"))
    assert len(albums) == 1
    assert len(albums[0]["photos"]) == 4
    assert len(albums[0]["groups"]) == 1


def test_two_differently_named_albums_both_keep_the_photo(tmp_path, pipeline):
    """
    Documented consequence, not a bug: photo albums are keyed by directory, so
    two groups whose roots have different basenames are two albums, and a
    photo in both belongs in both.
    """
    albums = _photo_albums(
        tmp_path, pipeline, _photos("demo35", root="pics") + _photos("media", root="images"))
    assert len(albums) == 2
    assert all(len(a["photos"]) == 4 for a in albums)


def test_one_group_of_photos_is_unchanged(tmp_path, pipeline):
    albums = _photo_albums(tmp_path, pipeline, _photos("solo"))
    assert len(albums) == 1
    assert albums[0]["groups"] == ["solo"]
    assert len(albums[0]["photos"]) == 4