package main

import (
	"context"
	"flag"
	"fmt"
	"log/slog"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/ethereum/go-ethereum/ethclient"

	"coppertone.tech/fraktal/mev-bot/pkg/arbitrage"
	"coppertone.tech/fraktal/mev-bot/pkg/cache"
	"coppertone.tech/fraktal/mev-bot/pkg/discovery"
	"coppertone.tech/fraktal/mev-bot/pkg/execution"
	"coppertone.tech/fraktal/mev-bot/pkg/observability"
)

func main() {
	// Command line flags
	rpcURL := flag.String("rpc", os.Getenv("ARBITRUM_RPC_URL"), "Arbitrum RPC URL")
	scanInterval := flag.Duration("interval", 30*time.Second, "Scan interval")
	minProfitBPS := flag.Int64("min-profit", 10, "Minimum profit in basis points (10 = 0.1%)")
	flag.Parse()

	if *rpcURL == "" {
		fmt.Println("Error: ARBITRUM_RPC_URL environment variable not set")
		fmt.Println("Usage: export ARBITRUM_RPC_URL=https://arb1.arbitrum.io/rpc")
		os.Exit(1)
	}

	// Setup logger
	logger := observability.NewLogger(slog.LevelInfo)
	logger.Info("MEV Flash Loan Bot starting",
		"rpcURL", *rpcURL,
		"scanInterval", scanInterval.String(),
		"minProfitBPS", *minProfitBPS,
	)

	// Connect to Arbitrum
	client, err := ethclient.Dial(*rpcURL)
	if err != nil {
		logger.Error("failed to connect to Arbitrum", "error", err)
		os.Exit(1)
	}
	defer client.Close()

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Verify connection
	chainID, err := client.ChainID(ctx)
	if err != nil {
		logger.Error("failed to get chain ID", "error", err)
		os.Exit(1)
	}
	logger.Info("connected to Arbitrum", "chainID", chainID.String())

	// Initialize components
	poolCache := cache.NewPoolCache()
	logger.Info("pool cache initialized")

	// Discover pools
	logger.Info("discovering UniswapV2 pools on Arbitrum...")
	poolDiscovery, err := discovery.NewUniswapV2PoolDiscovery(client, poolCache)
	if err != nil {
		logger.Error("failed to create pool discovery", "error", err)
		os.Exit(1)
	}

	poolCount, err := poolDiscovery.DiscoverMajorPools(ctx)
	if err != nil {
		logger.Error("failed to discover pools", "error", err)
		os.Exit(1)
	}
	logger.Info("pool discovery complete", "poolsFound", poolCount)

	// Initialize arbitrage detector
	arbConfig := arbitrage.Config{
		MinProfitBPS:    *minProfitBPS,
		MaxGasCostWei:   1e16, // 0.01 ETH
		SlippageBPS:     50,   // 0.5%
		MinLiquidityUSD: 10000,
	}
	detector, err := arbitrage.NewSimpleDetector(poolCache, logger, arbConfig)
	if err != nil {
		logger.Error("failed to create detector", "error", err)
		os.Exit(1)
	}
	logger.Info("arbitrage detector initialized", "minProfitBPS", arbConfig.MinProfitBPS)

	// Initialize flash loan executor (simulation mode until contract deployed)
	execConfig := execution.DefaultConfig()
	executor, err := execution.NewFlashLoanExecutor(
		client,
		nil, // No signer yet - will simulate only
		logger,
		execConfig,
	)
	if err != nil {
		// This will fail without a signer, which is expected for now
		logger.Warn("flash loan executor in simulation mode", "reason", "no signer configured")
	}

	// Setup graceful shutdown
	sigChan := make(chan os.Signal, 1)
	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)

	// Main loop
	ticker := time.NewTicker(*scanInterval)
	defer ticker.Stop()

	blockNumber := uint64(0)

	logger.Info("starting arbitrage scanner", "interval", scanInterval.String())
	logger.Info("")
	logger.Info("=== BOT READY ===")
	logger.Info("Scanning for profitable arbitrage opportunities...")
	logger.Info("Press Ctrl+C to stop")
	logger.Info("")

	for {
		select {
		case <-ticker.C:
			blockNumber++

			// Scan for opportunities
			opportunities, err := detector.ScanForOpportunities(ctx, blockNumber)
			if err != nil {
				logger.Error("scan failed", "error", err)
				continue
			}

			if len(opportunities) > 0 {
				logger.Info("opportunities found!", "count", len(opportunities))

				for i, opp := range opportunities {
					logger.Info(fmt.Sprintf("Opportunity #%d", i+1),
						"inputToken", opp.InputToken.Hex(),
						"bridgeToken", opp.BridgeToken.Hex(),
						"inputAmount", opp.InputAmount.String(),
						"outputAmount", opp.OutputAmount.String(),
						"profitAmount", opp.ProfitAmount.String(),
						"profitBPS", opp.ProfitBPS.String(),
						"pool1", opp.FirstPool.Address.Hex(),
						"pool2", opp.SecondPool.Address.Hex(),
					)

					// Simulate execution
					if executor != nil {
						result, err := executor.SimulateExecution(opp)
						if err != nil {
							logger.Error("simulation failed", "error", err)
							continue
						}

						logger.Info("simulation result",
							"grossProfit", result.GrossProfit.String(),
							"flashLoanFee", result.FlashLoanFee.String(),
							"netProfit", result.NetProfit.String(),
							"estimatedGas", result.EstimatedGas.String(),
							"finalProfit", result.FinalProfit.String(),
							"profitable", result.IsProfitable,
						)

						if result.IsProfitable {
							logger.Info("✅ PROFITABLE OPPORTUNITY FOUND!")
							logger.Info("Deploy flash loan contract to execute")
							logger.Info("See contracts/DEPLOY.md for instructions")
						}
					}
				}
			} else {
				logger.Debug("no opportunities found", "block", blockNumber)
			}

			// Show stats
			oppsFound, lastBlock := detector.GetStats()
			logger.Info("scan complete",
				"block", blockNumber,
				"totalOpportunities", oppsFound,
				"lastScanBlock", lastBlock,
			)

		case <-sigChan:
			logger.Info("shutdown signal received")
			logger.Info("shutting down gracefully...")

			// Print final stats
			oppsFound, _ := detector.GetStats()
			logger.Info("final statistics",
				"totalOpportunitiesFound", oppsFound,
			)

			if executor != nil {
				execCount, totalProfit := executor.GetStats()
				logger.Info("execution statistics",
					"executedCount", execCount,
					"totalProfit", totalProfit.String(),
				)
			}

			logger.Info("shutdown complete")
			return
		}
	}
}