"""Replay runner: execute backtest twice and assert identical output.

Usage:
  python -m apps.backtester.replay --manifest configs/experiments/baseline_v1.json \
    --snapshot-id snapshot_2026_03_20 --output-root ./runs
"""
from __future__ import annotations

import argparse
import json
import sys
from pathlib import Path

from libs.backtest.manifests import load_manifest, resolve_config
from libs.common.logging import get_logger

logger = get_logger(__name__)


def _run_once(
    manifest_path: str,
    snapshot_id: str | None,
    split: str,
    output_root: str,
    config_root: str,
    initial_equity: float,
) -> dict:
    """Execute one backtest run and return a dict of key determinism metrics."""
    from apps.backtester.run import BacktestRunner, _build_store
    from libs.backtest.manifests import load_manifest, resolve_config

    manifest = load_manifest(manifest_path)
    config = resolve_config(manifest, config_root=config_root, snapshot_id_override=snapshot_id)
    store = _build_store(manifest, config, split)

    runner = BacktestRunner(manifest=manifest, config=config, store=store, initial_equity=initial_equity)
    result = runner.run(output_root=output_root)

    # Build a determinism fingerprint (exclude timestamps and run_id)
    return {
        "trade_count": result.metrics.trade_count,
        "total_return_pct": result.metrics.total_return_pct,
        "max_drawdown_pct": result.metrics.max_drawdown_pct,
        "win_rate": result.metrics.win_rate,
        "avg_r_multiple": result.metrics.avg_r_multiple,
        "total_trading_days": result.total_trading_days,
        "total_candidates_seen": result.total_candidates_seen,
        "total_orders_rejected": result.total_orders_rejected,
    }


def run_replay(
    manifest_path: str,
    snapshot_id: str | None,
    split: str,
    output_root: str,
    config_root: str,
    initial_equity: float,
) -> bool:
    """Run twice and compare. Returns True if identical, False otherwise."""
    logger.info("replay_run_1_start")
    run1 = _run_once(manifest_path, snapshot_id, split, output_root, config_root, initial_equity)
    logger.info("replay_run_1_complete", metrics=run1)

    logger.info("replay_run_2_start")
    run2 = _run_once(manifest_path, snapshot_id, split, output_root, config_root, initial_equity)
    logger.info("replay_run_2_complete", metrics=run2)

    if run1 == run2:
        print("REPLAY PASS: runs are identical")
        print(json.dumps(run1, indent=2))
        return True
    else:
        print("REPLAY FAIL: runs differ!")
        print("Run 1:")
        print(json.dumps(run1, indent=2))
        print("Run 2:")
        print(json.dumps(run2, indent=2))
        diff = {k: (run1.get(k), run2.get(k)) for k in set(run1) | set(run2) if run1.get(k) != run2.get(k)}
        print("Differences:")
        print(json.dumps(diff, indent=2))
        return False


def main() -> None:
    parser = argparse.ArgumentParser(description="ACE-F Backtest Replay / Determinism Check")
    parser.add_argument("--manifest", required=True, help="Path to experiment manifest JSON")
    parser.add_argument("--snapshot-id", help="Override dataset_snapshot_id")
    parser.add_argument("--split", default="train")
    parser.add_argument("--output-root", default="./runs")
    parser.add_argument("--config-root", default=".")
    parser.add_argument("--initial-equity", type=float, default=100_000.0)
    args = parser.parse_args()

    ok = run_replay(
        manifest_path=args.manifest,
        snapshot_id=args.snapshot_id,
        split=args.split,
        output_root=args.output_root,
        config_root=args.config_root,
        initial_equity=args.initial_equity,
    )
    sys.exit(0 if ok else 1)


if __name__ == "__main__":
    main()