package manager

import (
	"bytes"
	"encoding/binary"
	"encoding/hex"
	"math/big"
	"slices"
	"strings"
	"sync"
	"time"

	"github.com/pkg/errors"
	"github.com/prometheus/client_golang/prometheus"
	"go.uber.org/zap"
	"source.quilibrium.com/quilibrium/monorepo/config"
	"source.quilibrium.com/quilibrium/monorepo/node/execution/engines"
	"source.quilibrium.com/quilibrium/monorepo/node/execution/intrinsics/compute"
	hypergraphintrinsic "source.quilibrium.com/quilibrium/monorepo/node/execution/intrinsics/hypergraph"
	"source.quilibrium.com/quilibrium/monorepo/node/execution/intrinsics/token"
	"source.quilibrium.com/quilibrium/monorepo/protobufs"
	"source.quilibrium.com/quilibrium/monorepo/types/compiler"
	"source.quilibrium.com/quilibrium/monorepo/types/crypto"
	"source.quilibrium.com/quilibrium/monorepo/types/execution"
	"source.quilibrium.com/quilibrium/monorepo/types/execution/intrinsics"
	"source.quilibrium.com/quilibrium/monorepo/types/execution/state"
	"source.quilibrium.com/quilibrium/monorepo/types/hypergraph"
	"source.quilibrium.com/quilibrium/monorepo/types/keys"
	"source.quilibrium.com/quilibrium/monorepo/types/store"
)

// ExecutionEngineManager manages the lifecycle and coordination of execution
// engines
type ExecutionEngineManager struct {
	logger            *zap.Logger
	config            *config.Config
	engines           map[string]execution.ShardExecutionEngine
	enginesMu         sync.RWMutex
	hypergraph        hypergraph.Hypergraph
	clockStore        store.ClockStore
	shardsStore       store.ShardsStore
	keyManager        keys.KeyManager
	inclusionProver   crypto.InclusionProver
	bulletproofProver crypto.BulletproofProver
	verEnc            crypto.VerifiableEncryptor
	decafConstructor  crypto.DecafConstructor
	compiler          compiler.CircuitCompiler
	frameProver       crypto.FrameProver
	includeGlobal     bool
	quit              chan struct{}
	wg                sync.WaitGroup
}

// NewExecutionEngineManager creates a new execution engine manager
func NewExecutionEngineManager(
	logger *zap.Logger,
	config *config.Config,
	hypergraph hypergraph.Hypergraph,
	clockStore store.ClockStore,
	shardsStore store.ShardsStore,
	keyManager keys.KeyManager,
	inclusionProver crypto.InclusionProver,
	bulletproofProver crypto.BulletproofProver,
	verEnc crypto.VerifiableEncryptor,
	decafConstructor crypto.DecafConstructor,
	compiler compiler.CircuitCompiler,
	frameProver crypto.FrameProver,
	includeGlobal bool,
) (*ExecutionEngineManager, error) {
	return &ExecutionEngineManager{
		logger: logger.With(
			zap.String("component", "execution_manager"),
		),
		config:            config,
		engines:           make(map[string]execution.ShardExecutionEngine),
		hypergraph:        hypergraph,
		clockStore:        clockStore,
		shardsStore:       shardsStore,
		keyManager:        keyManager,
		inclusionProver:   inclusionProver,
		bulletproofProver: bulletproofProver,
		verEnc:            verEnc,
		decafConstructor:  decafConstructor,
		compiler:          compiler,
		frameProver:       frameProver,
		includeGlobal:     includeGlobal,
		quit:              make(chan struct{}),
	}, nil
}

// InitializeEngines creates and registers all execution engines
func (m *ExecutionEngineManager) InitializeEngines() error {
	m.logger.Info("initializing execution engines")

	// Create all execution engines
	allEngines, err := engines.CreateAllEngines(
		m.logger,
		m.config.P2P,
		m.hypergraph,
		m.clockStore,
		m.shardsStore,
		m.keyManager,
		m.inclusionProver,
		m.bulletproofProver,
		m.verEnc,
		m.decafConstructor,
		m.compiler,
		m.frameProver,
		m.includeGlobal,
	)
	if err != nil {
		return errors.Wrap(err, "failed to create execution engines")
	}

	// Register each engine
	m.enginesMu.Lock()
	defer m.enginesMu.Unlock()

	for _, engine := range allEngines {
		name := engine.GetName()
		if _, exists := m.engines[name]; exists {
			return errors.Errorf("duplicate engine name: %s", name)
		}
		m.engines[name] = engine
		m.logger.Info("registered execution engine", zap.String("engine", name))
	}

	m.logger.Info(
		"initialized execution engines",
		zap.Int("count", len(m.engines)),
	)
	return nil
}

// StartAll starts all registered execution engines
func (m *ExecutionEngineManager) StartAll(quit chan struct{}) error {
	m.enginesMu.RLock()
	defer m.enginesMu.RUnlock()

	m.logger.Info("starting all execution engines")

	for name, engine := range m.engines {
		m.wg.Add(1)
		go func(name string, engine execution.ShardExecutionEngine) {
			defer m.wg.Done()

			m.logger.Info("starting execution engine", zap.String("engine", name))

			// Start the engine
			errChan := engine.Start()

			// Wait for any startup errors
			select {
			case err := <-errChan:
				if err != nil {
					m.logger.Error(
						"execution engine failed to start",
						zap.String("engine", name),
						zap.Error(err),
					)
				}
			case <-time.After(5 * time.Second):
				// Give engines time to report startup errors
				m.logger.Info(
					"execution engine started successfully",
					zap.String("engine", name),
				)
			}
		}(name, engine)
	}

	return nil
}

// StopAll stops all execution engines
func (m *ExecutionEngineManager) StopAll(force bool) error {
	m.enginesMu.RLock()
	defer m.enginesMu.RUnlock()

	m.logger.Info("stopping all execution engines")

	var stopErrors []error
	stopWg := sync.WaitGroup{}

	for name, engine := range m.engines {
		stopWg.Add(1)
		go func(name string, engine execution.ShardExecutionEngine) {
			defer stopWg.Done()

			m.logger.Info("stopping execution engine", zap.String("engine", name))

			errChan := engine.Stop(force)
			select {
			case err := <-errChan:
				if err != nil && !force {
					m.logger.Error(
						"error stopping execution engine",
						zap.String("engine", name),
						zap.Error(err),
					)
					stopErrors = append(stopErrors, err)
				}
			case <-time.After(10 * time.Second):
				if !force {
					err := errors.Errorf("timeout stopping engine: %s", name)
					m.logger.Error(
						"timeout stopping execution engine",
						zap.String("engine", name),
					)
					stopErrors = append(stopErrors, err)
				}
			}
		}(name, engine)
	}

	stopWg.Wait()

	if len(stopErrors) > 0 && !force {
		return errors.Errorf("failed to stop %d engines", len(stopErrors))
	}

	// Wait for all goroutines to finish
	done := make(chan struct{})
	go func() {
		m.wg.Wait()
		close(done)
	}()

	select {
	case <-done:
		m.logger.Info("all execution engines stopped")
	case <-time.After(30 * time.Second):
		if !force {
			return errors.New("timeout waiting for execution engines to stop")
		}
	}

	return nil
}

// GetEngine returns a specific execution engine by name
func (m *ExecutionEngineManager) GetEngine(
	name string,
) (execution.ShardExecutionEngine, bool) {
	m.enginesMu.RLock()
	defer m.enginesMu.RUnlock()

	engine, exists := m.engines[name]
	return engine, exists
}

// GetAllEngines returns all registered execution engines
func (
	m *ExecutionEngineManager,
) GetAllEngines() map[string]execution.ShardExecutionEngine {
	m.enginesMu.RLock()
	defer m.enginesMu.RUnlock()

	// Return a copy to prevent external modification
	enginesCopy := make(map[string]execution.ShardExecutionEngine)
	for name, engine := range m.engines {
		enginesCopy[name] = engine
	}
	return enginesCopy
}

// GetSupportedCapabilities returns all unique capabilities supported by the
// registered engines
func (
	m *ExecutionEngineManager,
) GetSupportedCapabilities() []*protobufs.Capability {
	m.enginesMu.RLock()
	defer m.enginesMu.RUnlock()

	// Use a map to track unique protocol identifiers
	uniqueCapabilities := make(map[uint32]*protobufs.Capability)

	// Iterate through all registered engines
	for name, engine := range m.engines {
		m.logger.Debug(
			"collecting capabilities from engine",
			zap.String("engine", name),
		)

		// Get capabilities from the engine
		capabilities := engine.GetCapabilities()

		// Add each capability to the map, using protocol identifier as key to
		// ensure uniqueness
		for _, capability := range capabilities {
			if capability != nil {
				if _, ok := uniqueCapabilities[capability.ProtocolIdentifier]; !ok {
					uniqueCapabilities[capability.ProtocolIdentifier] = capability
				}
			}
		}
	}

	// Convert map to slice
	result := make([]*protobufs.Capability, 0, len(uniqueCapabilities))
	for _, capability := range uniqueCapabilities {
		result = append(result, capability)
	}

	m.logger.Info("collected unique capabilities",
		zap.Int("total_unique", len(result)),
		zap.Int("engines_queried", len(m.engines)),
	)

	return result
}

func (m *ExecutionEngineManager) GetCost(message []byte) (*big.Int, error) {
	m.enginesMu.RLock()
	defer m.enginesMu.RUnlock()

	if len(message) < 4 {
		return nil, errors.Wrap(errors.New("invalid message"), "get cost")
	}

	messageType := binary.BigEndian.Uint32(message[:4])
	switch messageType {
	case protobufs.MessageBundleType:
		bundle := &protobufs.MessageBundle{}
		if err := bundle.FromCanonicalBytes(message); err != nil {
			return nil, errors.Wrap(err, "get cost")
		}

		sum := big.NewInt(0)
		for _, req := range bundle.Requests {
			cost, err := m.getRequestCost(req)
			if err != nil {
				return nil, errors.Wrap(err, "get cost")
			}
			sum.Add(sum, cost)
		}

		return sum, nil

	case protobufs.MessageRequestType:
		request := &protobufs.MessageRequest{}
		if err := request.FromCanonicalBytes(message); err != nil {
			return nil, errors.Wrap(err, "get cost")
		}

		cost, err := m.getRequestCost(request)
		return cost, errors.Wrap(err, "get cost")
	}

	return nil, errors.Wrap(errors.New("invalid message type"), "get cost")
}

func (m *ExecutionEngineManager) getRequestCost(
	request *protobufs.MessageRequest,
) (*big.Int, error) {
	requestBytes, err := request.ToCanonicalBytes()
	if err != nil {
		return nil, err
	}

	switch request.Request.(type) {
	case *protobufs.MessageRequest_Join:
		return big.NewInt(0), nil
	case *protobufs.MessageRequest_Leave:
		return big.NewInt(0), nil
	case *protobufs.MessageRequest_Pause:
		return big.NewInt(0), nil
	case *protobufs.MessageRequest_Resume:
		return big.NewInt(0), nil
	case *protobufs.MessageRequest_Confirm:
		return big.NewInt(0), nil
	case *protobufs.MessageRequest_Reject:
		return big.NewInt(0), nil
	case *protobufs.MessageRequest_Kick:
		return big.NewInt(0), nil
	case *protobufs.MessageRequest_Update:
		return big.NewInt(0), nil
	case *protobufs.MessageRequest_TokenDeploy:
		return m.engines["token"].GetCost(requestBytes)
	case *protobufs.MessageRequest_TokenUpdate:
		return m.engines["token"].GetCost(requestBytes)
	case *protobufs.MessageRequest_Transaction:
		return m.engines["token"].GetCost(requestBytes)
	case *protobufs.MessageRequest_PendingTransaction:
		return m.engines["token"].GetCost(requestBytes)
	case *protobufs.MessageRequest_MintTransaction:
		return m.engines["token"].GetCost(requestBytes)
	case *protobufs.MessageRequest_HypergraphDeploy:
		return m.engines["hypergraph"].GetCost(requestBytes)
	case *protobufs.MessageRequest_HypergraphUpdate:
		return m.engines["hypergraph"].GetCost(requestBytes)
	case *protobufs.MessageRequest_VertexAdd:
		return m.engines["hypergraph"].GetCost(requestBytes)
	case *protobufs.MessageRequest_VertexRemove:
		return m.engines["hypergraph"].GetCost(requestBytes)
	case *protobufs.MessageRequest_HyperedgeAdd:
		return m.engines["hypergraph"].GetCost(requestBytes)
	case *protobufs.MessageRequest_HyperedgeRemove:
		return m.engines["hypergraph"].GetCost(requestBytes)
	case *protobufs.MessageRequest_ComputeDeploy:
		return m.engines["compute"].GetCost(requestBytes)
	case *protobufs.MessageRequest_ComputeUpdate:
		return m.engines["compute"].GetCost(requestBytes)
	case *protobufs.MessageRequest_CodeDeploy:
		return m.engines["compute"].GetCost(requestBytes)
	case *protobufs.MessageRequest_CodeExecute:
		return m.engines["compute"].GetCost(requestBytes)
	case *protobufs.MessageRequest_CodeFinalize:
		return m.engines["compute"].GetCost(requestBytes)
	}

	return big.NewInt(0), nil
}

// ProcessMessage routes a message to the appropriate execution engine
func (m *ExecutionEngineManager) ProcessMessage(
	frameNumber uint64,
	feeMultiplier *big.Int,
	address []byte,
	message []byte,
	state state.State,
) (*execution.ProcessMessageResult, error) {
	m.enginesMu.RLock()
	defer m.enginesMu.RUnlock()

	// Route to global engine for system messages
	if bytes.Equal(address, intrinsics.GLOBAL_INTRINSIC_ADDRESS[:]) {
		if engine, exists := m.engines["global"]; exists {
			m.logger.Debug(
				"routing message to global engine",
				zap.String("address", hex.EncodeToString(address)),
			)

			timer := prometheus.NewTimer(
				executionRequestDuration.WithLabelValues("global"),
			)
			defer timer.ObserveDuration()

			result, err := engine.ProcessMessage(
				frameNumber,
				feeMultiplier,
				address,
				message,
				state,
			)
			if err != nil {
				executionRequestsTotal.WithLabelValues("global", "error").Inc()
				return nil, err
			}
			executionRequestsTotal.WithLabelValues("global", "success").Inc()
			return result, nil
		}
		executionRequestsTotal.WithLabelValues("global", "error").Inc()
		return nil, errors.Wrap(
			errors.New("global execution engine not found"),
			"process message",
		)
	}

	if m.config.P2P.Network == 0 {
		if frameNumber <= token.FRAME_2_1_EXTENDED_ENROLL_CONFIRM_END {
			return nil, errors.Wrap(
				errors.New("enrollment period has not ended"),
				"process message",
			)
		}
	}

	route := address

	if !(bytes.Equal(route, compute.COMPUTE_INTRINSIC_DOMAIN[:]) ||
		bytes.Equal(route, hypergraphintrinsic.HYPERGRAPH_BASE_DOMAIN[:]) ||
		bytes.Equal(route, token.TOKEN_BASE_DOMAIN[:]) ||
		bytes.Equal(route, token.QUIL_TOKEN_ADDRESS[:])) {
		metadata := slices.Concat(
			address,
			bytes.Repeat([]byte{0xff}, 32),
		)
		vertTree, err := m.hypergraph.GetVertexData([64]byte(metadata))
		if err != nil {
			executionRequestsTotal.WithLabelValues("unknown", "error").Inc()
			return nil, errors.Wrap(
				errors.Errorf(
					"no execution engine found for address: %x",
					address,
				),
				"process message",
			)
		}

		if vertTree == nil {
			return nil, errors.Wrap(
				errors.Errorf(
					"no metadata found for address: %x",
					address,
				),
				"process message",
			)
		}

		typeDomain, err := vertTree.Get(bytes.Repeat([]byte{0xff}, 32))
		if err != nil {
			executionRequestsTotal.WithLabelValues("unknown", "error").Inc()
			return nil, errors.Wrap(
				err,
				"process message",
			)
		}

		route = typeDomain
	}

	// Check compute domain
	if bytes.Equal(route, compute.COMPUTE_INTRINSIC_DOMAIN[:]) {
		if engine, exists := m.engines["compute"]; exists {
			m.logger.Debug(
				"routing message to compute engine",
				zap.String("address", hex.EncodeToString(address)),
			)

			timer := prometheus.NewTimer(
				executionRequestDuration.WithLabelValues("compute"),
			)
			defer timer.ObserveDuration()

			result, err := engine.ProcessMessage(
				frameNumber,
				feeMultiplier,
				address,
				message,
				state,
			)
			if err != nil {
				executionRequestsTotal.WithLabelValues("compute", "error").Inc()
				return nil, err
			}
			executionRequestsTotal.WithLabelValues("compute", "success").Inc()
			return result, nil
		}
		executionRequestsTotal.WithLabelValues("compute", "error").Inc()
		return nil, errors.Wrap(
			errors.New("compute execution engine not found"),
			"process message",
		)
	}

	// Check hypergraph domain
	if bytes.Equal(route, hypergraphintrinsic.HYPERGRAPH_BASE_DOMAIN[:]) {
		if engine, exists := m.engines["hypergraph"]; exists {
			m.logger.Debug(
				"routing message to hypergraph engine",
				zap.String("address", hex.EncodeToString(address)),
			)

			timer := prometheus.NewTimer(
				executionRequestDuration.WithLabelValues("hypergraph"),
			)
			defer timer.ObserveDuration()

			result, err := engine.ProcessMessage(
				frameNumber,
				feeMultiplier,
				address,
				message,
				state,
			)
			if err != nil {
				executionRequestsTotal.WithLabelValues("hypergraph", "error").Inc()
				return nil, err
			}
			executionRequestsTotal.WithLabelValues("hypergraph", "success").Inc()
			return result, nil
		}
		executionRequestsTotal.WithLabelValues("hypergraph", "error").Inc()
		return nil, errors.Wrap(
			errors.New("hypergraph execution engine not found"),
			"process message",
		)
	}

	// Check token addresses (both QUIL token and token base domain)
	if bytes.Equal(route, token.TOKEN_BASE_DOMAIN[:]) ||
		bytes.Equal(route, token.QUIL_TOKEN_ADDRESS[:]) {
		if engine, exists := m.engines["token"]; exists {
			m.logger.Debug(
				"routing message to token engine",
				zap.String("address", hex.EncodeToString(address)),
			)

			timer := prometheus.NewTimer(
				executionRequestDuration.WithLabelValues("token"),
			)
			defer timer.ObserveDuration()

			result, err := engine.ProcessMessage(
				frameNumber,
				feeMultiplier,
				address,
				message,
				state,
			)
			if err != nil {
				executionRequestsTotal.WithLabelValues("token", "error").Inc()
				return nil, err
			}
			executionRequestsTotal.WithLabelValues("token", "success").Inc()
			return result, nil
		}
		executionRequestsTotal.WithLabelValues("token", "error").Inc()
		return nil, errors.Wrap(
			errors.New("token execution engine not found"),
			"process message",
		)
	}

	return nil, errors.Wrap(
		errors.Errorf(
			"no execution engine found for address: %x",
			address,
		),
		"process message",
	)
}

// ValidateMessage validates a message without materializing state changes
func (m *ExecutionEngineManager) Lock(
	frameNumber uint64,
	address []byte,
	message []byte,
) error {
	m.enginesMu.RLock()
	defer m.enginesMu.RUnlock()

	engine := m.selectEngine(address)
	if engine == nil {
		return errors.Errorf("no execution engine found for address: %x", address)
	}

	return engine.Lock(frameNumber, address, message)
}

func (m *ExecutionEngineManager) Unlock() error {
	m.enginesMu.RLock()
	defer m.enginesMu.RUnlock()

	errs := []string{}
	for _, engine := range m.engines {
		err := engine.Unlock()
		if err != nil {
			errs = append(errs, err.Error())
		}
	}

	if len(errs) != 0 {
		return errors.Wrap(
			errors.Errorf("multiple errors: %s", strings.Join(errs, ", ")),
			"unlock",
		)
	}

	return nil
}

// ValidateMessage validates a message without materializing state changes
func (m *ExecutionEngineManager) ValidateMessage(
	frameNumber uint64,
	address []byte,
	message []byte,
) error {
	m.enginesMu.RLock()
	defer m.enginesMu.RUnlock()

	engine := m.selectEngine(address)
	if engine == nil {
		return errors.Errorf("no execution engine found for address: %x", address)
	}

	return engine.ValidateMessage(frameNumber, address, message)
}

// selectEngine selects the appropriate execution engine based on the address
// Note: This method assumes the caller holds at least a read lock on enginesMu
func (m *ExecutionEngineManager) selectEngine(
	address []byte,
) execution.ShardExecutionEngine {
	// Route to global engine for system messages
	if bytes.Equal(address, intrinsics.GLOBAL_INTRINSIC_ADDRESS[:]) {
		if engine, exists := m.engines["global"]; exists {
			return engine
		}
		return nil
	}

	// Route based on intrinsic domain (first 32 bytes)
	if len(address) >= 32 {
		// Check compute domain
		if bytes.Equal(address[:32], compute.COMPUTE_INTRINSIC_DOMAIN[:]) {
			if engine, exists := m.engines["compute"]; exists {
				return engine
			}
			return nil
		}

		// Check hypergraph domain
		if bytes.Equal(
			address[:32],
			hypergraphintrinsic.HYPERGRAPH_BASE_DOMAIN[:],
		) {
			if engine, exists := m.engines["hypergraph"]; exists {
				return engine
			}
			return nil
		}

		// Check token addresses (both QUIL token and token base domain)
		if bytes.Equal(address[:32], token.QUIL_TOKEN_ADDRESS) ||
			bytes.Equal(address[:32], token.TOKEN_BASE_DOMAIN[:]) {
			if engine, exists := m.engines["token"]; exists {
				return engine
			}
			return nil
		}
	}

	return nil
}

// RegisterAllEngines registers all engines from the manager with a consensus
// engine
func (m *ExecutionEngineManager) RegisterAllEngines(
	registerFunc func(execution.ShardExecutionEngine, uint64) <-chan error,
) error {
	m.enginesMu.RLock()
	defer m.enginesMu.RUnlock()

	for name, engine := range m.engines {
		errChan := registerFunc(engine, 0) // frame 0 for initial registration
		select {
		case err := <-errChan:
			if err != nil {
				return errors.Wrapf(err, "failed to register engine: %s", name)
			}
			m.logger.Info(
				"registered engine with consensus",
				zap.String("engine", name),
			)
		default:
			// Non-blocking, registration initiated
		}
	}

	return nil
}