"""Plex playlists: the current user's personal, orderable playlists of playable items."""

from typing import TYPE_CHECKING, Annotated

from fastapi import APIRouter, Depends
from pydantic import BaseModel, Field, model_validator
from sqlalchemy.orm import Session

from app.auth import current_user
from app.db import get_db
from app.models import User
from app.plex import queries, service
from app.plex.cards import display_title, leaf_card, norm_lang
from app.refusal import refused
from app.routes._common import not_found

if TYPE_CHECKING:
    from app.plex.models import PlexPlaylist

router = APIRouter(prefix="/api/plex", tags=["plex"])


def _playlist_card(pl: "PlexPlaylist", count: int, thumb_rk: str | None) -> dict:
    return {
        "id": pl.id,
        "title": pl.title,
        "item_count": count,
        "thumb": f"/api/plex/image/{thumb_rk}" if thumb_rk else None,
    }


def _card_of(db: Session, pl: "PlexPlaylist") -> dict:
    return _playlist_card(pl, queries.playlist_count(db, pl.id), queries.playlist_cover(db, pl.id))


def _own_playlist(db: Session, user: User, pid: int, *, lock: bool = False) -> "PlexPlaylist":
    pl = queries.own_playlist(db, user, pid, lock=lock)
    if pl is None:
        raise not_found("playlist")
    return pl


@router.get("/playlists")
def playlists(
    contains: str | None = None,
    contains_group: str | None = None,
    user: User = Depends(current_user),
    db: Session = Depends(get_db),
) -> dict:
    """The current user's playlists (newest-touched first), each with an item count + a cover thumb.
    `contains`=an item rating_key adds `has_item` per playlist (for the single 'add to playlist' dialog).
    `contains_group`=a comma-separated list of rating_keys adds `group_in` per playlist (how many of the
    group it already holds) + a top-level `group_size`, for the 'add a whole season/show' dialog."""
    contains_id = queries.item_id(db, contains) if contains else None
    group_ids: set[int] | None = None
    if contains_group is not None:
        group_ids = queries.item_ids(db, [s for s in (contains_group or "").split(",") if s])
    out = []
    for pl in queries.playlists_of(db, user):
        card = _card_of(db, pl)
        if contains_id is not None:
            card["has_item"] = queries.playlist_holds(db, pl.id, {contains_id}) > 0
        if group_ids is not None:
            card["group_in"] = queries.playlist_holds(db, pl.id, group_ids)
        out.append(card)
    resp: dict = {"playlists": out}
    if group_ids is not None:
        resp["group_size"] = len(group_ids)
    return resp


class CreatePlexPlaylistIn(BaseModel):
    title: str = ""
    item_rating_key: str = ""


@router.post("/playlists")
def create_playlist(
    body: CreatePlexPlaylistIn,
    user: User = Depends(current_user),
    db: Session = Depends(get_db),
) -> dict:
    title = body.title.strip()
    if not title:
        raise refused(400, "title_required")
    seed = queries.item(db, body.item_rating_key) if body.item_rating_key else None
    pl = service.create_playlist(db, user, title, seed)
    db.commit()
    return _playlist_card(pl, 1 if seed else 0, seed.rating_key if seed else None)


@router.get("/playlists/{pid}")
def playlist_detail(
    pid: int,
    lang: str = "en",
    user: User = Depends(current_user),
    db: Session = Depends(get_db),
) -> dict:
    lang = norm_lang(lang)
    pl = _own_playlist(db, user, pid)
    items = queries.playlist_items(db, pl.id)
    states = queries.states(db, user, [it.id for it in items])
    shows = queries.shows_by_ids(db, {it.show_id for it in items if it.show_id})
    cards = [
        leaf_card(
            it,
            states.get(it.id),
            display_title(shows[it.show_id], lang) if it.show_id in shows else None,
            shows[it.show_id].rating_key if it.show_id in shows else None,
            lang=lang,
        )
        for it in items
    ]
    return {"id": pl.id, "title": pl.title, "items": cards}


class RenamePlexPlaylistIn(BaseModel):
    title: str = ""


@router.patch("/playlists/{pid}")
def rename_playlist(
    pid: int,
    body: RenamePlexPlaylistIn,
    user: User = Depends(current_user),
    db: Session = Depends(get_db),
) -> dict:
    pl = _own_playlist(db, user, pid)
    title = body.title.strip()
    if not title:
        raise refused(400, "title_required")
    service.rename_playlist(pl, title)
    db.commit()
    return _playlist_card(pl, queries.playlist_count(db, pl.id), queries.playlist_cover(db, pl.id))


@router.delete("/playlists/{pid}")
def delete_playlist(
    pid: int, user: User = Depends(current_user), db: Session = Depends(get_db)
) -> dict:
    pl = _own_playlist(db, user, pid)
    service.delete_playlist(db, pl)
    db.commit()
    return {"deleted": pid}


class PlexItemRefIn(BaseModel):
    item_rating_key: str = ""


@router.post("/playlists/{pid}/items")
def playlist_add_item(
    pid: int,
    body: PlexItemRefIn,
    user: User = Depends(current_user),
    db: Session = Depends(get_db),
) -> dict:
    # Locked (like every add / reorder here): two adds otherwise read the same max position.
    pl = _own_playlist(db, user, pid, lock=True)
    it = queries.item(db, body.item_rating_key)
    if it is None:
        raise not_found("item")
    service.add_item(db, pl, it)
    db.commit()
    return {"ok": True}


@router.delete("/playlists/{pid}/items/{item_rating_key}")
def playlist_remove_item(
    pid: int,
    item_rating_key: str,
    user: User = Depends(current_user),
    db: Session = Depends(get_db),
) -> dict:
    # Locked like the adds and the reorder: the list row first, then its items — a remove that
    # locked an item row before a reorder locked the list deadlocked against it.
    pl = _own_playlist(db, user, pid, lock=True)
    it = queries.item(db, item_rating_key)
    if it is not None:
        service.remove_item(db, pl, it)
    db.commit()
    return {"ok": True}


class PlexItemKeysIn(BaseModel):
    item_rating_keys: list[str] = []


class PlexItemAddBulkIn(PlexItemKeysIn):
    # Where each key goes back (the list page's "Undo" of a removal): an index over the
    # ORDERED rows, one per key. The two-call shape (append, then send the whole order) leaves the rows
    # at the end whenever the second call fails, and the order it sends would overwrite anything
    # another tab changed in between.
    positions: list[Annotated[int, Field(ge=0)]] | None = None

    @model_validator(mode="after")
    def _one_position_per_key(self):
        if self.positions is not None and len(self.positions) != len(self.item_rating_keys):
            raise ValueError("positions must pair one-to-one with item_rating_keys")
        return self


@router.post("/playlists/{pid}/items/bulk")
def playlist_add_bulk(
    pid: int,
    body: PlexItemAddBulkIn,
    user: User = Depends(current_user),
    db: Session = Depends(get_db),
) -> dict:
    """Append many items at once (a whole season/show). Already-present items are skipped; the input
    order is preserved for the newly-added ones. With `positions`, each key is put back at its index
    instead of appended. Returns how many were added + the new total."""
    pl = _own_playlist(db, user, pid, lock=True)
    items = queries.items_by_keys(db, body.item_rating_keys)
    if body.positions is not None:
        by_rk = {it.rating_key: it for it in items}
        placed = [
            (at, by_rk[str(rk)])
            for rk, at in zip(body.item_rating_keys, body.positions, strict=True)
            if str(rk) in by_rk
        ]
        added = service.insert_items_at(db, pl, placed)
    else:
        added = service.add_items(db, pl, items)
    db.commit()
    return {"ok": True, "added": added, "item_count": queries.playlist_count(db, pid)}


@router.post("/playlists/{pid}/items/remove-bulk")
def playlist_remove_bulk(
    pid: int,
    body: PlexItemKeysIn,
    user: User = Depends(current_user),
    db: Session = Depends(get_db),
) -> dict:
    """Remove many items at once (a whole season/show, or a multi-select). Returns how many were
    removed + the new total."""
    pl = _own_playlist(db, user, pid, lock=True)
    ids = [it.id for it in queries.items_by_keys(db, body.item_rating_keys)]
    removed = service.remove_items(db, pl, ids)
    db.commit()
    return {"ok": True, "removed": removed, "item_count": queries.playlist_count(db, pid)}


@router.put("/playlists/{pid}/order")
def reorder_playlist(
    pid: int,
    body: PlexItemKeysIn,
    user: User = Depends(current_user),
    db: Session = Depends(get_db),
) -> dict:
    """Set the playlist order from an explicit list of item rating_keys (0-based positions)."""
    pl = _own_playlist(db, user, pid, lock=True)
    service.reorder_playlist(db, pl, body.item_rating_keys)
    db.commit()
    return {"ok": True}