"""
scripts/download_data.py

Usage example:
python scripts/download_data.py ^
  --symbols EURUSD USDJPY GBPUSD USDCHF AUDUSD NZDUSD ^
  --timeframes M15 H1 H4 ^
  --start 2016-01-01 ^
  --end 2026-01-01 ^
  --output data/raw ^
  --format parquet
"""

from __future__ import annotations

import argparse
import sys
from datetime import datetime
from pathlib import Path


def _find_repo_root(start: Path) -> Path:
    """Walk up from start until a directory containing `src` is found."""
    current = start.resolve()
    while True:
        if (current / "src").is_dir():
            return current
        if current.parent == current:
            break
        current = current.parent

    raise RuntimeError("Cannot locate repository root (directory containing 'src').")


ROOT = _find_repo_root(Path(__file__).parent)
if str(ROOT) not in sys.path:
    sys.path.insert(0, str(ROOT))

from src.data.mt5_fetcher import MT5Config, MT5Fetcher  # noqa: E402

DEFAULT_SYMBOLS = ["EURUSD", "USDJPY", "GBPUSD", "USDCHF", "AUDUSD", "NZDUSD"]
DEFAULT_TIMEFRAMES = ["M15", "H1", "H4"]


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description="Download Forex historical data from MT5")

    parser.add_argument(
        "--symbols",
        nargs="+",
        default=DEFAULT_SYMBOLS,
        help="List of symbols to download",
    )
    parser.add_argument(
        "--timeframes",
        nargs="+",
        default=DEFAULT_TIMEFRAMES,
        help="List of timeframes, e.g. M15 H1 H4",
    )
    parser.add_argument(
        "--start",
        required=True,
        help="Start date in YYYY-MM-DD",
    )
    parser.add_argument(
        "--end",
        required=True,
        help="End date in YYYY-MM-DD",
    )
    parser.add_argument(
        "--output",
        default="data/raw",
        help="Output directory",
    )
    parser.add_argument(
        "--format",
        choices=["parquet", "csv"],
        default="parquet",
        help="File format",
    )
    parser.add_argument(
        "--terminal-path",
        default=None,
        help="Optional MT5 terminal path",
    )
    parser.add_argument(
        "--login",
        type=int,
        default=None,
        help="Optional MT5 login",
    )
    parser.add_argument(
        "--password",
        default=None,
        help="Optional MT5 password",
    )
    parser.add_argument(
        "--server",
        default=None,
        help="Optional MT5 server name",
    )

    return parser.parse_args()


def main() -> None:
    args = parse_args()

    start = datetime.fromisoformat(args.start)
    end = datetime.fromisoformat(args.end)
    output_dir = Path(args.output)

    config = MT5Config(
        terminal_path=args.terminal_path,
        login=args.login,
        password=args.password,
        server=args.server,
    )
    fetcher = MT5Fetcher(config)

    try:
        print("[INFO] Initializing MT5...")
        fetcher.initialize()
        print("[INFO] MT5 initialized.")

        for symbol in args.symbols:
            for timeframe in args.timeframes:
                print(f"[INFO] Downloading {symbol} {timeframe} ...")
                df = fetcher.fetch_range(
                    symbol=symbol,
                    timeframe=timeframe,
                    start=start,
                    end=end,
                )

                stats = fetcher.validate_bars(df)
                save_dir = output_dir / symbol / timeframe
                saved_path = fetcher.save_dataframe(
                    df=df,
                    output_dir=save_dir,
                    symbol=symbol,
                    timeframe=timeframe,
                    fmt=args.format,
                )

                print(
                    f"[OK] {symbol} {timeframe} | rows={stats['rows']} | "
                    f"start={stats['start']} | end={stats['end']} | "
                    f"dup={stats['duplicate_timestamps']} | "
                    f"nulls={stats['null_count']} | "
                    f"bad_ohlc={stats['bad_ohlc_rows']} | "
                    f"saved={saved_path}"
                )

        print("[DONE] Download completed successfully.")

    finally:
        fetcher.shutdown()
        print("[INFO] MT5 shutdown.")


if __name__ == "__main__":
    main()