"""
Слой доступа к данным (SQLite).

Использует thread-local соединения — каждый поток получает своё соединение
и переиспользует его, вместо создания нового на каждый запрос.
"""
import json
import sqlite3
import threading

import config

_local = threading.local()


def _connect() -> sqlite3.Connection:
    """Возвращает соединение для текущего потока (создаёт при первом вызове)."""
    conn = getattr(_local, "conn", None)
    if conn is None:
        conn = sqlite3.connect(config.DB_FILE, check_same_thread=False)
        conn.row_factory = sqlite3.Row
        _local.conn = conn
    return conn


def init_db():
    with _connect() as conn:
        conn.execute("""
            CREATE TABLE IF NOT EXISTS messages (
                task_id     INTEGER PRIMARY KEY,
                message_id  INTEGER NOT NULL,
                task_number TEXT,
                group_id    INTEGER DEFAULT 0,
                base_text   TEXT
            )
        """)
        for col, dfn in [
            ("group_id",    "INTEGER DEFAULT 0"),
            ("base_text",   "TEXT"),
            ("events_json", "TEXT"),
        ]:
            try:
                conn.execute(f"ALTER TABLE messages ADD COLUMN {col} {dfn}")
            except Exception:
                pass

        conn.execute("""
            CREATE TABLE IF NOT EXISTS ref_data (
                entity TEXT    NOT NULL,
                id     INTEGER NOT NULL,
                name   TEXT    NOT NULL,
                PRIMARY KEY (entity, id)
            )
        """)

        conn.execute("""
            CREATE TABLE IF NOT EXISTS responsible (
                task_id   INTEGER NOT NULL,
                user_id   INTEGER NOT NULL,
                user_name TEXT    NOT NULL,
                PRIMARY KEY (task_id, user_id)
            )
        """)

        conn.execute("""
            CREATE TABLE IF NOT EXISTS gif_messages (
                task_id    INTEGER PRIMARY KEY,
                message_id INTEGER NOT NULL
            )
        """)
        try:
            conn.execute("SELECT 1 FROM gif_messages LIMIT 1")
        except Exception:
            conn.execute("""
                CREATE TABLE gif_messages (
                    task_id    INTEGER PRIMARY KEY,
                    message_id INTEGER NOT NULL
                )
            """)
        conn.commit()


# ── messages ──────────────────────────────────────────────────────────────────

def get_message_id(task_id: int):
    row = _connect().execute(
        "SELECT message_id FROM messages WHERE task_id = ?", (task_id,)
    ).fetchone()
    return row["message_id"] if row else None


def get_message_data(task_id: int) -> dict | None:
    row = _connect().execute(
        "SELECT message_id, task_number, group_id, base_text FROM messages WHERE task_id = ?",
        (task_id,),
    ).fetchone()
    return dict(row) if row else None


def get_task_id_by_number(task_number: str) -> int | None:
    row = _connect().execute(
        "SELECT task_id FROM messages WHERE task_number = ?", (str(task_number),)
    ).fetchone()
    return row["task_id"] if row else None


def save_message_id(
    task_id: int,
    message_id: int,
    task_number: str = None,
    group_id: int = 0,
    base_text: str = None,
):
    conn = _connect()
    row = conn.execute(
        "SELECT events_json FROM messages WHERE task_id = ?", (task_id,)
    ).fetchone()
    existing_events = row["events_json"] if row else None

    conn.execute(
        """INSERT OR REPLACE INTO messages
           (task_id, message_id, task_number, group_id, base_text, events_json)
           VALUES (?, ?, ?, ?, ?, ?)""",
        (task_id, message_id, task_number, group_id or 0, base_text, existing_events),
    )
    conn.commit()


def get_stored_events(task_id: int) -> list[str]:
    row = _connect().execute(
        "SELECT events_json FROM messages WHERE task_id = ?", (task_id,)
    ).fetchone()
    if not row or not row["events_json"]:
        return []
    try:
        return json.loads(row["events_json"])
    except Exception:
        return []


def save_stored_events(task_id: int, events: list[str]):
    conn = _connect()
    conn.execute(
        "UPDATE messages SET events_json = ? WHERE task_id = ?",
        (json.dumps(events, ensure_ascii=False), task_id),
    )
    conn.commit()


# ── ref_data ──────────────────────────────────────────────────────────────────

def save_ref_data(entity: str, items: list[tuple[int, str]]):
    conn = _connect()
    conn.executemany(
        "INSERT OR REPLACE INTO ref_data (entity, id, name) VALUES (?, ?, ?)",
        [(entity, item_id, name) for item_id, name in items],
    )
    conn.commit()


def resolve(entity: str, item_id: int | None) -> str | None:
    if item_id is None:
        return None
    row = _connect().execute(
        "SELECT name FROM ref_data WHERE entity = ? AND id = ?",
        (entity, item_id),
    ).fetchone()
    return row["name"] if row else None


def get_all_ref(entity: str) -> list[dict]:
    rows = _connect().execute(
        "SELECT id, name FROM ref_data WHERE entity = ? ORDER BY name",
        (entity,),
    ).fetchall()
    return [{"id": r["id"], "name": r["name"]} for r in rows]


# ── responsible ───────────────────────────────────────────────────────────────

def add_responsible(task_id: int, user_id: int, user_name: str):
    conn = _connect()
    conn.execute(
        "INSERT OR REPLACE INTO responsible (task_id, user_id, user_name) VALUES (?, ?, ?)",
        (task_id, user_id, user_name),
    )
    conn.commit()


def remove_responsible(task_id: int, user_id: int):
    conn = _connect()
    conn.execute(
        "DELETE FROM responsible WHERE task_id = ? AND user_id = ?",
        (task_id, user_id),
    )
    conn.commit()


def get_responsible(task_id: int) -> list[dict]:
    rows = _connect().execute(
        "SELECT user_id, user_name FROM responsible WHERE task_id = ? ORDER BY rowid",
        (task_id,),
    ).fetchall()
    return [{"user_id": r["user_id"], "user_name": r["user_name"]} for r in rows]


# ── gif_messages ──────────────────────────────────────────────────────────────

def get_gif_message_id(task_id: int) -> int | None:
    row = _connect().execute(
        "SELECT message_id FROM gif_messages WHERE task_id = ?", (task_id,)
    ).fetchone()
    return row["message_id"] if row else None


def save_gif_message_id(task_id: int, message_id: int):
    conn = _connect()
    conn.execute(
        "INSERT OR REPLACE INTO gif_messages (task_id, message_id) VALUES (?, ?)",
        (task_id, message_id),
    )
    conn.commit()


def delete_gif_message_id(task_id: int):
    conn = _connect()
    conn.execute("DELETE FROM gif_messages WHERE task_id = ?", (task_id,))
    conn.commit()