from __future__ import annotations

import sqlite3
from datetime import datetime, timezone, timedelta
from pathlib import Path
from typing import Any

SCHEMA = """
CREATE TABLE IF NOT EXISTS candles (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    symbol TEXT NOT NULL,
    timeframe TEXT NOT NULL,
    open REAL NOT NULL,
    high REAL NOT NULL,
    low REAL NOT NULL,
    close REAL NOT NULL,
    start_ts INTEGER NOT NULL,
    end_ts INTEGER NOT NULL,
    UNIQUE(symbol, timeframe, start_ts)
);
"""


def connect(db_path: str | Path) -> sqlite3.Connection:
    conn = sqlite3.connect(str(db_path))
    conn.row_factory = sqlite3.Row
    return conn


def init_db(db_path: str | Path) -> None:
    path = Path(db_path)
    path.parent.mkdir(parents=True, exist_ok=True)
    with connect(path) as conn:
        conn.executescript(SCHEMA)
        conn.execute(
            "CREATE UNIQUE INDEX IF NOT EXISTS idx_candles_symbol_timeframe_start_ts ON candles(symbol, timeframe, start_ts)"
        )
        conn.commit()


def upsert_candle(db_path: str | Path, candle: dict[str, Any]) -> None:
    with connect(db_path) as conn:
        conn.execute(
            """
            INSERT INTO candles(symbol, timeframe, open, high, low, close, start_ts, end_ts)
            VALUES(?, ?, ?, ?, ?, ?, ?, ?)
            ON CONFLICT(symbol, timeframe, start_ts) DO UPDATE SET
                open=excluded.open,
                high=excluded.high,
                low=excluded.low,
                close=excluded.close,
                end_ts=excluded.end_ts
            """,
            (
                candle["symbol"],
                candle["timeframe"],
                candle["open"],
                candle["high"],
                candle["low"],
                candle["close"],
                candle["start_ts"],
                candle["end_ts"],
            ),
        )
        conn.commit()


def latest_candles(db_path: str | Path, symbol: str, timeframe: str, limit: int = 100) -> list[dict[str, Any]]:
    with connect(db_path) as conn:
        rows = conn.execute(
            """
            SELECT symbol, timeframe, open, high, low, close, start_ts, end_ts
            FROM candles
            WHERE symbol = ? AND timeframe = ?
            ORDER BY start_ts DESC
            LIMIT ?
            """,
            (symbol, timeframe, limit),
        ).fetchall()
    return [dict(row) for row in reversed(rows)]


def last_candle(db_path: str | Path, symbol: str, timeframe: str) -> dict[str, Any] | None:
    with connect(db_path) as conn:
        row = conn.execute(
            """
            SELECT symbol, timeframe, open, high, low, close, start_ts, end_ts
            FROM candles
            WHERE symbol = ? AND timeframe = ?
            ORDER BY start_ts DESC
            LIMIT 1
            """,
            (symbol, timeframe),
        ).fetchone()
    return dict(row) if row else None


def stats(db_path: str | Path) -> dict[str, Any]:
    with connect(db_path) as conn:
        candles = conn.execute("SELECT COUNT(*) AS n FROM candles").fetchone()["n"]
    return {"candles": candles}


def prune_candles_older_than(db_path: str | Path, days: int) -> int:
    if days <= 0:
        return 0
    cutoff = int((datetime.now(timezone.utc) - timedelta(days=days)).timestamp() * 1000)
    with connect(db_path) as conn:
        cursor = conn.execute("DELETE FROM candles WHERE end_ts < ?", (cutoff,))
        conn.commit()
        return int(cursor.rowcount or 0)