package main

import (
	"flag"
	"os"
	"path/filepath"
	"time"

	"alpaca-bot/internal/alpaca"
	"alpaca-bot/internal/backtest"
	"alpaca-bot/internal/config"
	"alpaca-bot/internal/logger"
	"alpaca-bot/internal/strategy"

	"github.com/joho/godotenv"
	"github.com/xuri/excelize/v2"
)

func main() {
	_ = godotenv.Load()
	log := logger.New("[BACKTEST]")

	cfg := config.LoadAlpaca()

	// CLI flags
	symbol := flag.String("symbol", "AAPL", "Stock symbol")
	tf := flag.String("tf", "1Day", "Timeframe")
	startStr := flag.String("start", "2023-01-01", "Start date")
	endStr := flag.String("end", "2026-01-01", "End date")
	cash := flag.Float64("cash", 10000, "Start capital")
	risk := flag.Float64("risk", 0.02, "Risk per trade (fraction)")
	atrPeriod := flag.Int("atr", 14, "ATR period")
	atrMult := flag.Float64("atrMult", 1.5, "ATR multiplier for stop")
	tpMult := flag.Float64("tpMult", 2.0, "Take profit multiplier")
	fast := flag.Int("fast", 12, "Fast EMA")
	slow := flag.Int("slow", 26, "Slow EMA")
	out := flag.String("out", "output/backtest.xlsx", "Excel output path")
	flag.Parse()

	start, err := time.Parse("2006-01-02", *startStr)
	if err != nil {
		log.Fatal("invalid start date:", err)
	}
	end, err := time.Parse("2006-01-02", *endStr)
	if err != nil {
		log.Fatal("invalid end date:", err)
	}

	// Create output folder
	if err := os.MkdirAll(filepath.Dir(*out), 0755); err != nil {
		log.Fatal(err)
	}

	// Load historical bars from Alpaca
	client := alpaca.NewClient(cfg)
	bars, err := client.GetHistoricalBars(*symbol, *tf, start, end)
	if err != nil {
		log.Fatal(err)
	}
	log.Printf("Loaded %d bars for %s", len(bars), *symbol)

	// Initialize EMA crossover strategy
	strat := strategy.NewEMACross(*fast, *slow)

	// Initialize backtest engine with ATR stops and TakeProfit
	engine := backtest.NewEngine(*symbol, strat, *cash, *risk, *atrPeriod, *atrMult, *tpMult)
	engine.Run(bars)

	log.Printf("Backtest finished | Trades: %d | End Cash: %.2f", len(engine.Trades), engine.Cash)

	// Export trades to Excel
	f := excelize.NewFile()
	sheet := "Backtest"
	f.NewSheet(sheet)

	headers := []string{"Time", "Symbol", "Side", "Price", "Qty", "Cash", "StopPrice", "TakeProfit"}
	for i, h := range headers {
		cell, _ := excelize.CoordinatesToCellName(i+1, 1)
		f.SetCellValue(sheet, cell, h)
	}

	for i, t := range engine.Trades {
		row := i + 2
		values := []interface{}{t.Time.Format("2006-01-02 15:04:05"), t.Symbol, t.Side, t.Price, t.Qty, t.Cash, t.StopPrice, t.TakeProfit}
		for colIdx, val := range values {
			cell, _ := excelize.CoordinatesToCellName(colIdx+1, row)
			f.SetCellValue(sheet, cell, val)
		}
	}

	if err := f.SaveAs(*out); err != nil {
		log.Fatal("failed to save Excel:", err)
	}

	log.Printf("Backtest Excel saved to %s", *out)
}