"""SQLite persistence for weekly episode tracking."""
import os
import sqlite3
from datetime import datetime, timezone, timedelta
from contextlib import contextmanager

DB_PATH = os.environ.get("DB_PATH", "/app/data/episodes.db")
SEED_EPISODE = 928


@contextmanager
def _conn():
    os.makedirs(os.path.dirname(DB_PATH), exist_ok=True)
    con = sqlite3.connect(DB_PATH)
    con.row_factory = sqlite3.Row
    try:
        yield con
        con.commit()
    finally:
        con.close()


def init_db():
    """Create table and seed with the initial previous-week episode if empty."""
    with _conn() as con:
        con.execute("""
            CREATE TABLE IF NOT EXISTS weekly_episodes (
                id              INTEGER PRIMARY KEY AUTOINCREMENT,
                episode_number  INTEGER NOT NULL,
                week_start      TEXT NOT NULL,
                week_end        TEXT NOT NULL,
                item_id         TEXT,
                media_name      TEXT,
                watched_at      TEXT,
                recorded_at     TEXT DEFAULT (datetime('now'))
            )
        """)
        count = con.execute("SELECT COUNT(*) FROM weekly_episodes").fetchone()[0]
        if count == 0:
            _seed(con)


def _seed(con):
    """Seed with episode 928 for the week before the current week."""
    from datetime import date
    PHT = timezone(timedelta(hours=8))
    now_pht = datetime.now(PHT)
    days_since_sunday = (now_pht.weekday() + 1) % 7
    current_sunday = (now_pht - timedelta(days=days_since_sunday)).date()
    prev_sunday = current_sunday - timedelta(weeks=1)
    prev_saturday = prev_sunday + timedelta(days=6)
    con.execute(
        "INSERT INTO weekly_episodes (episode_number, week_start, week_end, media_name) VALUES (?,?,?,?)",
        (SEED_EPISODE, prev_sunday.isoformat(), prev_saturday.isoformat(), "seed"),
    )


def save_episode(episode_number: int, week_start: str, week_end: str,
                 item_id: str = None, media_name: str = None, watched_at: str = None):
    """Insert or replace the episode record for this week."""
    with _conn() as con:
        existing = con.execute(
            "SELECT id FROM weekly_episodes WHERE week_start = ?", (week_start,)
        ).fetchone()
        if existing:
            con.execute(
                """UPDATE weekly_episodes
                   SET episode_number=?, item_id=?, media_name=?, watched_at=?, recorded_at=datetime('now')
                   WHERE week_start=?""",
                (episode_number, item_id, media_name, watched_at, week_start),
            )
        else:
            con.execute(
                """INSERT INTO weekly_episodes
                   (episode_number, week_start, week_end, item_id, media_name, watched_at)
                   VALUES (?,?,?,?,?,?)""",
                (episode_number, week_start, week_end, item_id, media_name, watched_at),
            )


def get_previous_episode(week_start: str) -> dict | None:
    """Return the most recent episode record strictly before week_start."""
    with _conn() as con:
        row = con.execute(
            """SELECT * FROM weekly_episodes
               WHERE week_start < ?
               ORDER BY week_start DESC LIMIT 1""",
            (week_start,),
        ).fetchone()
    return dict(row) if row else None


def get_all_history() -> list:
    """Return all weekly episode records, newest first."""
    with _conn() as con:
        rows = con.execute(
            "SELECT * FROM weekly_episodes ORDER BY week_start DESC"
        ).fetchall()
    return [dict(r) for r in rows]