package orchestrator

import (
	"context"
	"fmt"
	"math/big"
	"sync"
	"time"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/fraktal/mev-beta/internal/config"
	"github.com/fraktal/mev-beta/internal/logger"
	"github.com/fraktal/mev-beta/pkg/arbitrage"
	"github.com/fraktal/mev-beta/pkg/events"
	"github.com/fraktal/mev-beta/pkg/market"
	"github.com/fraktal/mev-beta/pkg/pools"
	"github.com/fraktal/mev-beta/pkg/scanner"
)

// MEVCoordinator orchestrates the entire MEV detection pipeline
type MEVCoordinator struct {
	// Configuration
	config *config.Config
	logger *logger.Logger

	// Core components
	eventParser      *events.EventParser
	poolDiscovery    *pools.PoolDiscovery
	marketManager    *market.MarketManager
	marketScanner    *scanner.MarketScanner
	arbitrageScanner *arbitrage.MultiHopScanner

	// Data flow channels
	rawTransactions chan *RawTransaction
	parsedEvents    chan *events.Event
	poolUpdates     chan *PoolUpdate
	arbitrageOppCh  chan *ArbitrageOpportunity

	// Coordination
	wg     sync.WaitGroup
	ctx    context.Context
	cancel context.CancelFunc

	// Metrics
	metrics *CoordinatorMetrics
}

// RawTransaction represents a transaction to be processed
type RawTransaction struct {
	Transaction *types.Transaction
	Receipt     *types.Receipt
	BlockNumber uint64
	Timestamp   uint64
}

// PoolUpdate represents a pool state update
type PoolUpdate struct {
	PoolAddress common.Address
	Token0      common.Address
	Token1      common.Address
	Reserve0    *big.Int
	Reserve1    *big.Int
	Timestamp   time.Time
}

// ArbitrageOpportunity represents a detected arbitrage opportunity
type ArbitrageOpportunity struct {
	Paths        []*arbitrage.ArbitragePath
	TriggerToken common.Address
	Amount       *big.Int
	NetProfit    *big.Int
	ROI          float64
	DetectedAt   time.Time
}

// CoordinatorMetrics tracks performance metrics
type CoordinatorMetrics struct {
	TransactionsProcessed uint64
	EventsParsed          uint64
	PoolsDiscovered       uint64
	OpportunitiesFound    uint64
	AverageProcessingTime time.Duration

	mutex sync.RWMutex
}

// NewMEVCoordinator creates a new MEV coordinator
func NewMEVCoordinator(
	config *config.Config,
	logger *logger.Logger,
	eventParser *events.EventParser,
	poolDiscovery *pools.PoolDiscovery,
	marketManager *market.MarketManager,
	marketScanner *scanner.MarketScanner,
) *MEVCoordinator {
	ctx, cancel := context.WithCancel(context.Background())

	arbitrageScanner := arbitrage.NewMultiHopScanner(logger, marketManager)

	return &MEVCoordinator{
		config:           config,
		logger:           logger,
		eventParser:      eventParser,
		poolDiscovery:    poolDiscovery,
		marketManager:    marketManager,
		marketScanner:    marketScanner,
		arbitrageScanner: arbitrageScanner,

		// Buffered channels for smooth data flow
		rawTransactions: make(chan *RawTransaction, config.Bot.ChannelBufferSize),
		parsedEvents:    make(chan *events.Event, config.Bot.ChannelBufferSize),
		poolUpdates:     make(chan *PoolUpdate, config.Bot.ChannelBufferSize),
		arbitrageOppCh:  make(chan *ArbitrageOpportunity, 100),

		ctx:     ctx,
		cancel:  cancel,
		metrics: &CoordinatorMetrics{},
	}
}

// Start begins the MEV coordination pipeline
func (mc *MEVCoordinator) Start() error {
	mc.logger.Info("Starting MEV Coordinator pipeline...")

	// Start pipeline stages
	mc.startTransactionProcessor()
	mc.startEventProcessor()
	mc.startPoolUpdateProcessor()
	mc.startArbitrageProcessor()
	mc.startOpportunityHandler()
	mc.startMetricsReporter()

	mc.logger.Info("MEV Coordinator pipeline started successfully")
	return nil
}

// Stop gracefully shuts down the coordinator
func (mc *MEVCoordinator) Stop() {
	mc.logger.Info("Stopping MEV Coordinator pipeline...")

	// Cancel context to stop all goroutines
	mc.cancel()

	// Wait for all goroutines to finish
	mc.wg.Wait()

	// Close channels
	close(mc.rawTransactions)
	close(mc.parsedEvents)
	close(mc.poolUpdates)
	close(mc.arbitrageOppCh)

	mc.logger.Info("MEV Coordinator pipeline stopped")
}

// ProcessTransaction submits a transaction for processing through the pipeline
func (mc *MEVCoordinator) ProcessTransaction(tx *types.Transaction, receipt *types.Receipt, blockNumber uint64, timestamp uint64) {
	select {
	case mc.rawTransactions <- &RawTransaction{
		Transaction: tx,
		Receipt:     receipt,
		BlockNumber: blockNumber,
		Timestamp:   timestamp,
	}:
	case <-mc.ctx.Done():
		return
	default:
		// Channel full, log and skip
		mc.logger.Warn("Transaction processing channel full, skipping transaction")
	}
}

// startTransactionProcessor processes raw transactions and extracts events
func (mc *MEVCoordinator) startTransactionProcessor() {
	mc.wg.Add(1)
	go func() {
		defer mc.wg.Done()

		for {
			select {
			case rawTx := <-mc.rawTransactions:
				start := time.Now()
				mc.processRawTransaction(rawTx)

				// Update metrics
				mc.updateMetrics(time.Since(start))

			case <-mc.ctx.Done():
				return
			}
		}
	}()
}

// processRawTransaction processes a single raw transaction
func (mc *MEVCoordinator) processRawTransaction(rawTx *RawTransaction) {
	// Parse events from transaction
	events, err := mc.eventParser.ParseTransactionReceipt(
		rawTx.Receipt,
		rawTx.BlockNumber,
		rawTx.Timestamp,
	)
	if err != nil {
		mc.logger.Debug(fmt.Sprintf("Failed to parse transaction %s: %v", rawTx.Transaction.Hash().Hex(), err))
		return
	}

	// Also try to parse events directly from transaction data
	txEvents, err := mc.eventParser.ParseTransaction(rawTx.Transaction, rawTx.BlockNumber, rawTx.Timestamp)
	if err == nil {
		events = append(events, txEvents...)
	}

	// Submit events for processing
	for _, event := range events {
		select {
		case mc.parsedEvents <- event:
		case <-mc.ctx.Done():
			return
		default:
			mc.logger.Warn("Event processing channel full, skipping event")
		}
	}

	mc.metrics.mutex.Lock()
	mc.metrics.TransactionsProcessed++
	mc.metrics.EventsParsed += uint64(len(events))
	mc.metrics.mutex.Unlock()
}

// startEventProcessor processes parsed events
func (mc *MEVCoordinator) startEventProcessor() {
	// Start multiple event processors for concurrency
	for i := 0; i < mc.config.Bot.MaxWorkers; i++ {
		mc.wg.Add(1)
		go func(workerID int) {
			defer mc.wg.Done()

			for {
				select {
				case event := <-mc.parsedEvents:
					mc.processEvent(event, workerID)

				case <-mc.ctx.Done():
					return
				}
			}
		}(i)
	}
}

// processEvent processes a single parsed event
func (mc *MEVCoordinator) processEvent(event *events.Event, workerID int) {
	mc.logger.Debug(fmt.Sprintf("Worker %d processing %s event from pool %s",
		workerID, event.Type.String(), event.PoolAddress.Hex()))

	// Submit to pool discovery for potential new pool detection
	mc.submitToPoolDiscovery(event)

	// Submit to market scanner for analysis
	mc.marketScanner.SubmitEvent(*event)

	// Update pool state if this is a swap event
	if event.Type == events.Swap {
		mc.updatePoolState(event)

		// Trigger arbitrage scan for significant swaps
		if mc.isSignificantSwap(event) {
			mc.triggerArbitrageScan(event)
		}
	}
}

// submitToPoolDiscovery submits event to pool discovery system
func (mc *MEVCoordinator) submitToPoolDiscovery(event *events.Event) {
	// Convert event to pool discovery format
	logData := map[string]interface{}{
		"data":   "",
		"topics": []interface{}{},
	}

	// Submit for discovery analysis
	mc.poolDiscovery.DiscoverFromTransaction(
		event.TransactionHash.Hex(),
		event.PoolAddress.Hex(),
		"",
		[]interface{}{logData},
	)
}

// updatePoolState updates pool state from swap events
func (mc *MEVCoordinator) updatePoolState(event *events.Event) {
	if event.SqrtPriceX96 != nil && event.Liquidity != nil {
		mc.marketManager.UpdatePool(
			event.PoolAddress,
			event.Liquidity,
			event.SqrtPriceX96,
			event.Tick,
		)

		// Send pool update notification
		select {
		case mc.poolUpdates <- &PoolUpdate{
			PoolAddress: event.PoolAddress,
			Token0:      event.Token0,
			Token1:      event.Token1,
			Timestamp:   time.Now(),
		}:
		case <-mc.ctx.Done():
			return
		default:
			// Channel full, continue
		}
	}
}

// isSignificantSwap determines if a swap is significant enough to trigger arbitrage scanning
func (mc *MEVCoordinator) isSignificantSwap(event *events.Event) bool {
	// Check if swap amount is above threshold
	minAmount := big.NewInt(1000000000000000000) // 1 ETH equivalent

	if event.Amount0 != nil && event.Amount0.Cmp(minAmount) > 0 {
		return true
	}
	if event.Amount1 != nil && event.Amount1.Cmp(minAmount) > 0 {
		return true
	}

	return false
}

// triggerArbitrageScan triggers an arbitrage scan for the given event
func (mc *MEVCoordinator) triggerArbitrageScan(event *events.Event) {
	go func() {
		// Determine the token and amount to scan for
		var triggerToken common.Address
		var amount *big.Int

		if event.Amount0 != nil && event.Amount0.Sign() > 0 {
			triggerToken = event.Token0
			amount = event.Amount0
		} else if event.Amount1 != nil && event.Amount1.Sign() > 0 {
			triggerToken = event.Token1
			amount = event.Amount1
		} else {
			return
		}

		// Scan for arbitrage opportunities
		ctx, cancel := context.WithTimeout(mc.ctx, 5*time.Second)
		defer cancel()

		paths, err := mc.arbitrageScanner.ScanForArbitrage(ctx, triggerToken, amount)
		if err != nil {
			mc.logger.Debug(fmt.Sprintf("Arbitrage scan failed: %v", err))
			return
		}

		if len(paths) > 0 {
			// Calculate total profit from all paths
			totalProfit := big.NewInt(0)
			for _, path := range paths {
				totalProfit.Add(totalProfit, path.NetProfit)
			}

			opportunity := &ArbitrageOpportunity{
				Paths:        paths,
				TriggerToken: triggerToken,
				Amount:       amount,
				NetProfit:    totalProfit,
				ROI:          paths[0].ROI, // Use ROI from best path
				DetectedAt:   time.Now(),
			}

			select {
			case mc.arbitrageOppCh <- opportunity:
			case <-mc.ctx.Done():
				return
			default:
				mc.logger.Warn("Arbitrage opportunity channel full")
			}
		}
	}()
}

// startPoolUpdateProcessor processes pool updates
func (mc *MEVCoordinator) startPoolUpdateProcessor() {
	mc.wg.Add(1)
	go func() {
		defer mc.wg.Done()

		for {
			select {
			case poolUpdate := <-mc.poolUpdates:
				mc.logger.Debug(fmt.Sprintf("Pool update for %s: %s/%s",
					poolUpdate.PoolAddress.Hex(),
					poolUpdate.Token0.Hex(),
					poolUpdate.Token1.Hex()))

			case <-mc.ctx.Done():
				return
			}
		}
	}()
}

// startArbitrageProcessor processes arbitrage opportunities
func (mc *MEVCoordinator) startArbitrageProcessor() {
	mc.wg.Add(1)
	go func() {
		defer mc.wg.Done()

		for {
			select {
			case <-mc.ctx.Done():
				return
			}
		}
	}()
}

// startOpportunityHandler handles detected arbitrage opportunities
func (mc *MEVCoordinator) startOpportunityHandler() {
	mc.wg.Add(1)
	go func() {
		defer mc.wg.Done()

		for {
			select {
			case opp := <-mc.arbitrageOppCh:
				mc.handleArbitrageOpportunity(opp)

			case <-mc.ctx.Done():
				return
			}
		}
	}()
}

// handleArbitrageOpportunity handles a detected arbitrage opportunity
func (mc *MEVCoordinator) handleArbitrageOpportunity(opp *ArbitrageOpportunity) {
	mc.logger.Info(fmt.Sprintf("🎯 ARBITRAGE OPPORTUNITY DETECTED!"))
	mc.logger.Info(fmt.Sprintf("  Token: %s", opp.TriggerToken.Hex()))
	mc.logger.Info(fmt.Sprintf("  Amount: %s wei", opp.Amount.String()))
	mc.logger.Info(fmt.Sprintf("  Net Profit: %s wei", opp.NetProfit.String()))
	mc.logger.Info(fmt.Sprintf("  ROI: %.2f%%", opp.ROI))
	mc.logger.Info(fmt.Sprintf("  Paths: %d", len(opp.Paths)))

	for i, path := range opp.Paths {
		mc.logger.Info(fmt.Sprintf("  Path %d: %d hops, %s profit, %.2f%% ROI",
			i+1, len(path.Tokens)-1, path.NetProfit.String(), path.ROI))

		pathStr := path.Tokens[0].Hex()[:8]
		for j := 1; j < len(path.Tokens); j++ {
			pathStr += " -> " + path.Tokens[j].Hex()[:8]
		}
		mc.logger.Info(fmt.Sprintf("    Route: %s", pathStr))
	}

	mc.metrics.mutex.Lock()
	mc.metrics.OpportunitiesFound++
	mc.metrics.mutex.Unlock()
}

// startMetricsReporter reports metrics periodically
func (mc *MEVCoordinator) startMetricsReporter() {
	mc.wg.Add(1)
	go func() {
		defer mc.wg.Done()

		ticker := time.NewTicker(30 * time.Second)
		defer ticker.Stop()

		for {
			select {
			case <-ticker.C:
				mc.reportMetrics()

			case <-mc.ctx.Done():
				return
			}
		}
	}()
}

// reportMetrics logs current metrics
func (mc *MEVCoordinator) reportMetrics() {
	mc.metrics.mutex.RLock()
	defer mc.metrics.mutex.RUnlock()

	mc.logger.Info(fmt.Sprintf("📊 MEV COORDINATOR METRICS:"))
	mc.logger.Info(fmt.Sprintf("  Transactions Processed: %d", mc.metrics.TransactionsProcessed))
	mc.logger.Info(fmt.Sprintf("  Events Parsed: %d", mc.metrics.EventsParsed))
	mc.logger.Info(fmt.Sprintf("  Pools Discovered: %d", mc.metrics.PoolsDiscovered))
	mc.logger.Info(fmt.Sprintf("  Opportunities Found: %d", mc.metrics.OpportunitiesFound))
	mc.logger.Info(fmt.Sprintf("  Avg Processing Time: %v", mc.metrics.AverageProcessingTime))
}

// updateMetrics updates processing time metrics
func (mc *MEVCoordinator) updateMetrics(processingTime time.Duration) {
	mc.metrics.mutex.Lock()
	defer mc.metrics.mutex.Unlock()

	// Calculate rolling average
	if mc.metrics.AverageProcessingTime == 0 {
		mc.metrics.AverageProcessingTime = processingTime
	} else {
		mc.metrics.AverageProcessingTime = (mc.metrics.AverageProcessingTime + processingTime) / 2
	}
}