"""Index des médias et des guets, en SQLite.

Les fichiers vivent sur le disque ; la base ne porte que leurs métadonnées et l'état de la
synchronisation. Un client ne demande que ce qui a changé depuis son dernier passage, d'où le
champ `updated_at` sur chaque ligne.
"""
from __future__ import annotations

import sqlite3
import time
import uuid
from dataclasses import asdict, dataclass
from pathlib import Path

SCHEMA = """
CREATE TABLE IF NOT EXISTS media (
    id          TEXT PRIMARY KEY,
    title       TEXT NOT NULL,
    artist      TEXT NOT NULL DEFAULT '',
    source      TEXT NOT NULL,
    origin      TEXT NOT NULL DEFAULT '',
    filename    TEXT NOT NULL,
    mime        TEXT NOT NULL DEFAULT 'audio/mpeg',
    size        INTEGER NOT NULL DEFAULT 0,
    duration_ms INTEGER NOT NULL DEFAULT 0,
    artwork_url TEXT,
    state       TEXT NOT NULL DEFAULT 'pending',
    error       TEXT,
    remote_url  TEXT,
    created_at  INTEGER NOT NULL,
    updated_at  INTEGER NOT NULL
);
CREATE INDEX IF NOT EXISTS media_updated ON media(updated_at);

CREATE TABLE IF NOT EXISTS watches (
    id          TEXT PRIMARY KEY,
    query       TEXT NOT NULL,
    created_at  INTEGER NOT NULL,
    scans       INTEGER NOT NULL DEFAULT 0,
    last_scan   INTEGER,
    found_at    INTEGER,
    found_on    TEXT,
    found_title TEXT
);
"""


@dataclass
class Media:
    id: str
    title: str
    artist: str
    source: str
    origin: str
    filename: str
    mime: str
    size: int
    duration_ms: int
    artwork_url: str | None
    state: str
    error: str | None
    remote_url: str | None
    created_at: int
    updated_at: int

    def public(self) -> dict:
        """Vue destinée au client : ni chemin local, ni URL d'origine."""
        data = asdict(self)
        data.pop("remote_url")
        data.pop("filename")
        return data


def now() -> int:
    return int(time.time() * 1000)


class Storage:
    def __init__(self, db_path: Path) -> None:
        db_path.parent.mkdir(parents=True, exist_ok=True)
        self._db = sqlite3.connect(db_path, check_same_thread=False)
        self._db.row_factory = sqlite3.Row
        self._db.executescript(SCHEMA)
        self._db.commit()

    # --- Médias ---------------------------------------------------------

    def add_media(self, *, title: str, artist: str, source: str, origin: str,
                  filename: str, remote_url: str | None, mime: str = "audio/mpeg",
                  duration_ms: int = 0, artwork_url: str | None = None,
                  state: str = "pending") -> str:
        media_id = uuid.uuid4().hex
        stamp = now()
        self._db.execute(
            "INSERT INTO media (id,title,artist,source,origin,filename,mime,size,duration_ms,"
            "artwork_url,state,error,remote_url,created_at,updated_at) "
            "VALUES (?,?,?,?,?,?,?,0,?,?,?,NULL,?,?,?)",
            (media_id, title, artist, source, origin, filename, mime, duration_ms,
             artwork_url, state, remote_url, stamp, stamp),
        )
        self._db.commit()
        return media_id

    def update_media(self, media_id: str, **fields) -> None:
        if not fields:
            return
        fields["updated_at"] = now()
        assignments = ", ".join(f"{key} = ?" for key in fields)
        self._db.execute(
            f"UPDATE media SET {assignments} WHERE id = ?", (*fields.values(), media_id)
        )
        self._db.commit()

    def media(self, media_id: str) -> Media | None:
        row = self._db.execute("SELECT * FROM media WHERE id = ?", (media_id,)).fetchone()
        return Media(**dict(row)) if row else None

    def media_since(self, since: int = 0, state: str | None = "ready") -> list[Media]:
        query = "SELECT * FROM media WHERE updated_at > ?"
        params: list = [since]
        if state:
            query += " AND state = ?"
            params.append(state)
        query += " ORDER BY updated_at ASC"
        return [Media(**dict(r)) for r in self._db.execute(query, params)]

    def pending_downloads(self) -> list[Media]:
        return [
            Media(**dict(r))
            for r in self._db.execute(
                "SELECT * FROM media WHERE state IN ('pending','failed') AND remote_url IS NOT NULL "
                "ORDER BY created_at ASC LIMIT 20"
            )
        ]

    def delete_media(self, media_id: str) -> Media | None:
        item = self.media(media_id)
        if item:
            self._db.execute("DELETE FROM media WHERE id = ?", (media_id,))
            self._db.commit()
        return item

    # --- Guets ----------------------------------------------------------

    def add_watch(self, query: str) -> str:
        watch_id = uuid.uuid4().hex
        self._db.execute(
            "INSERT INTO watches (id,query,created_at) VALUES (?,?,?)",
            (watch_id, query.strip(), now()),
        )
        self._db.commit()
        return watch_id

    def watches(self) -> list[dict]:
        return [dict(r) for r in self._db.execute("SELECT * FROM watches ORDER BY created_at DESC")]

    def pending_watches(self) -> list[dict]:
        return [dict(r) for r in self._db.execute("SELECT * FROM watches WHERE found_at IS NULL")]

    def mark_watch_found(self, watch_id: str, station: str, title: str) -> None:
        self._db.execute(
            "UPDATE watches SET found_at=?, found_on=?, found_title=? WHERE id=?",
            (now(), station, title, watch_id),
        )
        self._db.commit()

    def mark_watches_scanned(self, ids: list[str]) -> None:
        if not ids:
            return
        stamp = now()
        self._db.executemany(
            "UPDATE watches SET scans = scans + 1, last_scan = ? WHERE id = ?",
            [(stamp, i) for i in ids],
        )
        self._db.commit()

    def delete_watch(self, watch_id: str) -> None:
        self._db.execute("DELETE FROM watches WHERE id = ?", (watch_id,))
        self._db.commit()