"""CTA strategy parameter optimization wrapper using vnpy_ctastrategy.backtesting."""
import sys
import os
import traceback
import uuid
from datetime import datetime
from pathlib import Path
from typing import List, Any

# Add vnpy source to path for local development
_VNPY_SRC = os.path.join(os.path.dirname(__file__), "..", "vnpy_v4.4.0")
_VNPY_SRC = os.path.abspath(_VNPY_SRC)
if _VNPY_SRC not in sys.path:
    sys.path.insert(0, _VNPY_SRC)

from sanguo_backtest.result_store import BacktestResult, save_result
from sanguo_backtest.cta_engine import guess_exchange, Exchange


def run_cta_optimization(
    strategy_class,
    symbol: str,
    grid: dict,
    start: str,
    end: str,
    cfg,
    db_path: str,
    max_workers: int = 2
) -> List[BacktestResult]:
    """
    Run CTA strategy parameter optimization using vnpy_ctastrategy BacktestingEngine.

    Args:
        strategy_class: CTA strategy class to optimize
        symbol: Stock symbol (e.g., "600000")
        grid: Parameter grid dict {name: (start, end, step)}
        start: Backtest start date (YYYY-MM-DD format)
        end: Backtest end date (YYYY-MM-DD format)
        cfg: Configuration object (may contain data paths)
        db_path: SQLite database path for saving results
        max_workers: Maximum number of parallel optimization workers

    Returns:
        List[BacktestResult]: List of result objects with optimization statistics
    """
    # Generate unique task ID for this optimization run
    task_id = f"opt_{uuid.uuid4().hex[:8]}"

    try:
        # Lazy import of BacktestingEngine and OptimizationSetting
        from vnpy_ctastrategy.backtesting import BacktestingEngine
        from vnpy.trader.optimize import OptimizationSetting

        # Build vt_symbol for A-shares
        vt_symbol = f"{symbol}.{guess_exchange(symbol).value}"

        # Convert date strings to datetime objects
        start_dt = datetime.strptime(start, "%Y-%m-%d")
        end_dt = datetime.strptime(end, "%Y-%m-%d") if end else None

        # Create and configure backtesting engine
        engine = BacktestingEngine()

        # Set parameters with A-share specific values (same as cta_engine)
        engine.set_parameters(
            vt_symbol=vt_symbol,
            interval="1d",  # Daily interval for A-shares
            start=start_dt,
            end=end_dt,
            rate=0.001,  # Commission rate (0.1% for A-shares)
            slippage=0,  # No slippage for simplicity
            size=1,  # Contract size (1 for stocks)
            pricetick=0.01,  # Minimum price tick (0.01 yuan for A-shares)
            capital=0  # No initial capital limit
        )

        # Add strategy without parameters (will be set by optimization)
        engine.add_strategy(strategy_class, {})

        # Load historical data
        engine.load_data()

        # Create optimization setting
        setting = OptimizationSetting()
        setting.set_target("sharpe_ratio")  # Optimize for Sharpe ratio

        # Add parameter ranges to optimization setting
        for name, (start_val, end_val, step) in grid.items():
            setting.add_parameter(name, start_val, end_val, step)

        # Run optimization (headless, with parallel workers)
        optimization_results = engine.run_optimization(
            setting,
            output=False,  # Headless mode
            max_workers=max_workers
        )

        # Parse optimization results and convert to BacktestResult objects
        results = []
        for item in optimization_results:
            try:
                # Handle both tuple format (params, target_value, statistics)
                # and dict format ({params: ..., statistics: ...})
                if isinstance(item, tuple) and len(item) >= 3:
                    params = item[0]
                    statistics = item[2]
                elif isinstance(item, dict):
                    params = item.get("params", {})
                    statistics = item.get("statistics", {})
                else:
                    # Unknown format, skip this result
                    continue

                # Create individual result for each optimization run
                result = BacktestResult(
                    task_id=f"opt_{uuid.uuid4().hex[:8]}",  # Unique ID per result
                    type="optimize",
                    status="done",
                    strategy=strategy_class.__name__,
                    symbol=symbol,
                    params=params,
                    start=start,
                    end=end,
                    statistics=statistics,
                    equity_curve=None,  # Not available in optimization results
                    trades=None  # Not available in optimization results
                )
                results.append(result)

                # Save each result to database
                save_result(result, db_path=db_path)

            except Exception as e:
                # Handle individual result parsing error
                error_result = BacktestResult(
                    task_id=f"opt_{uuid.uuid4().hex[:8]}",
                    type="optimize",
                    status="failed",
                    strategy=strategy_class.__name__,
                    symbol=symbol,
                    params={},
                    start=start,
                    end=end,
                    statistics={},
                    equity_curve=None,
                    trades=None,
                    error_msg=f"Result parsing error: {type(e).__name__}: {e}"
                )
                results.append(error_result)
                save_result(error_result, db_path=db_path)

        return results

    except Exception as e:
        # Handle any exceptions during optimization setup/execution
        error_msg = f"{type(e).__name__}: {e}\n{traceback.format_exc()}"

        failed_result = BacktestResult(
            task_id=task_id,
            type="optimize",
            status="failed",
            strategy=strategy_class.__name__,
            symbol=symbol,
            params={},
            start=start,
            end=end,
            statistics={},
            equity_curve=None,
            trades=None,
            error_msg=error_msg
        )

        # Save failed result to database
        save_result(failed_result, db_path=db_path)

        return [failed_result]


# Module-level reference for mocking in tests
BacktestingEngine = None  # Will be set when imported inside run_cta_optimization
OptimizationSetting = None  # Will be set when imported inside run_cta_optimization