package orchestrator

import (
	"context"

	"github.com/tech/sendico/payments/storage"
	"github.com/tech/sendico/payments/storage/model"
	"github.com/tech/sendico/pkg/api/routers"
	clockpkg "github.com/tech/sendico/pkg/clock"
	msg "github.com/tech/sendico/pkg/messaging"
	mb "github.com/tech/sendico/pkg/messaging/broker"
	"github.com/tech/sendico/pkg/mlogger"
	orchestratorv1 "github.com/tech/sendico/pkg/proto/payments/orchestrator/v1"
	"google.golang.org/grpc"
)

type serviceError string

func (e serviceError) Error() string {
	return string(e)
}

const (
	defaultFeeQuoteTTLMillis int64 = 120000
	defaultOracleTTLMillis   int64 = 60000
)

var (
	errStorageUnavailable = serviceError("payments.orchestrator: storage not initialised")
)

// Service orchestrates payments across ledger, billing, FX, and chain domains.
type Service struct {
	logger  mlogger.Logger
	storage storage.Repository
	clock   clockpkg.Clock

	deps serviceDependencies
	h    handlerSet
	comp componentSet

	gatewayBroker    mb.Broker
	gatewayConsumers []msg.Consumer

	orchestratorv1.UnimplementedPaymentOrchestratorServer
}

type serviceDependencies struct {
	fees                  feesDependency
	ledger                ledgerDependency
	gateway               gatewayDependency
	railGateways          railGatewayDependency
	providerGateway       providerGatewayDependency
	oracle                oracleDependency
	mntx                  mntxDependency
	gatewayRegistry       GatewayRegistry
	gatewayInvokeResolver GatewayInvokeResolver
	cardRoutes            map[string]CardGatewayRoute
	feeLedgerAccounts     map[string]string
	planBuilder           PlanBuilder
}

type handlerSet struct {
	commands *paymentCommandFactory
	queries  *paymentQueryHandler
	events   *paymentEventHandler
}

type componentSet struct {
	executor *paymentExecutor
}

// NewService constructs a payment orchestrator service.
func NewService(logger mlogger.Logger, repo storage.Repository, opts ...Option) *Service {
	svc := &Service{
		logger:  logger.Named("payment_orchestrator"),
		storage: repo,
		clock:   clockpkg.NewSystem(),
	}

	initMetrics()

	for _, opt := range opts {
		if opt != nil {
			opt(svc)
		}
	}

	if svc.clock == nil {
		svc.clock = clockpkg.NewSystem()
	}

	engine := defaultPaymentEngine{svc: svc}
	svc.h.commands = newPaymentCommandFactory(engine, svc.logger)
	svc.h.queries = newPaymentQueryHandler(svc.storage, svc.ensureRepository, svc.logger.Named("queries"))
	svc.h.events = newPaymentEventHandler(svc.storage, svc.ensureRepository, svc.logger.Named("events"), svc.submitCardPayout, svc.resumePaymentPlan, svc.releasePaymentHold)
	svc.comp.executor = newPaymentExecutor(&svc.deps, svc.logger.Named("payment_executor"), svc)
	svc.startGatewayConsumers()

	return svc
}

func (s *Service) ensureHandlers() {
	if s.h.commands == nil {
		s.h.commands = newPaymentCommandFactory(defaultPaymentEngine{svc: s}, s.logger)
	}
	if s.h.queries == nil {
		s.h.queries = newPaymentQueryHandler(s.storage, s.ensureRepository, s.logger.Named("queries"))
	}
	if s.h.events == nil {
		s.h.events = newPaymentEventHandler(s.storage, s.ensureRepository, s.logger.Named("events"), s.submitCardPayout, s.resumePaymentPlan, s.releasePaymentHold)
	}
	if s.comp.executor == nil {
		s.comp.executor = newPaymentExecutor(&s.deps, s.logger.Named("payment_executor"), s)
	}
}

// Register attaches the service to the supplied gRPC router.
func (s *Service) Register(router routers.GRPC) error {
	return router.Register(func(reg grpc.ServiceRegistrar) {
		orchestratorv1.RegisterPaymentOrchestratorServer(reg, s)
	})
}

// QuotePayment aggregates downstream quotes.
func (s *Service) QuotePayment(ctx context.Context, req *orchestratorv1.QuotePaymentRequest) (*orchestratorv1.QuotePaymentResponse, error) {
	s.ensureHandlers()
	return executeUnary(ctx, s, "QuotePayment", s.h.commands.QuotePayment().Execute, req)
}

// QuotePayments aggregates downstream quotes for multiple intents.
func (s *Service) QuotePayments(ctx context.Context, req *orchestratorv1.QuotePaymentsRequest) (*orchestratorv1.QuotePaymentsResponse, error) {
	s.ensureHandlers()
	return executeUnary(ctx, s, "QuotePayments", s.h.commands.QuotePayments().Execute, req)
}

// InitiatePayment captures a payment intent and reserves funds orchestration.
func (s *Service) InitiatePayment(ctx context.Context, req *orchestratorv1.InitiatePaymentRequest) (*orchestratorv1.InitiatePaymentResponse, error) {
	s.ensureHandlers()
	return executeUnary(ctx, s, "InitiatePayment", s.h.commands.InitiatePayment().Execute, req)
}

// InitiatePayments executes multiple payments using a stored quote reference.
func (s *Service) InitiatePayments(ctx context.Context, req *orchestratorv1.InitiatePaymentsRequest) (*orchestratorv1.InitiatePaymentsResponse, error) {
	s.ensureHandlers()
	return executeUnary(ctx, s, "InitiatePayments", s.h.commands.InitiatePayments().Execute, req)
}

// CancelPayment attempts to cancel an in-flight payment.
func (s *Service) CancelPayment(ctx context.Context, req *orchestratorv1.CancelPaymentRequest) (*orchestratorv1.CancelPaymentResponse, error) {
	s.ensureHandlers()
	return executeUnary(ctx, s, "CancelPayment", s.h.commands.CancelPayment().Execute, req)
}

// GetPayment returns a stored payment record.
func (s *Service) GetPayment(ctx context.Context, req *orchestratorv1.GetPaymentRequest) (*orchestratorv1.GetPaymentResponse, error) {
	s.ensureHandlers()
	return executeUnary(ctx, s, "GetPayment", s.h.queries.getPayment, req)
}

// ListPayments lists stored payment records.
func (s *Service) ListPayments(ctx context.Context, req *orchestratorv1.ListPaymentsRequest) (*orchestratorv1.ListPaymentsResponse, error) {
	s.ensureHandlers()
	return executeUnary(ctx, s, "ListPayments", s.h.queries.listPayments, req)
}

// InitiateConversion orchestrates standalone FX conversions.
func (s *Service) InitiateConversion(ctx context.Context, req *orchestratorv1.InitiateConversionRequest) (*orchestratorv1.InitiateConversionResponse, error) {
	s.ensureHandlers()
	return executeUnary(ctx, s, "InitiateConversion", s.h.commands.InitiateConversion().Execute, req)
}

// ProcessTransferUpdate reconciles chain events back into payment state.
func (s *Service) ProcessTransferUpdate(ctx context.Context, req *orchestratorv1.ProcessTransferUpdateRequest) (*orchestratorv1.ProcessTransferUpdateResponse, error) {
	s.ensureHandlers()
	return executeUnary(ctx, s, "ProcessTransferUpdate", s.h.events.processTransferUpdate, req)
}

// ProcessDepositObserved reconciles deposit events to ledger.
func (s *Service) ProcessDepositObserved(ctx context.Context, req *orchestratorv1.ProcessDepositObservedRequest) (*orchestratorv1.ProcessDepositObservedResponse, error) {
	s.ensureHandlers()
	return executeUnary(ctx, s, "ProcessDepositObserved", s.h.events.processDepositObserved, req)
}

// ProcessCardPayoutUpdate reconciles card payout events back into payment state.
func (s *Service) ProcessCardPayoutUpdate(ctx context.Context, req *orchestratorv1.ProcessCardPayoutUpdateRequest) (*orchestratorv1.ProcessCardPayoutUpdateResponse, error) {
	s.ensureHandlers()
	return executeUnary(ctx, s, "ProcessCardPayoutUpdate", s.h.events.processCardPayoutUpdate, req)
}

func (s *Service) executePayment(ctx context.Context, store storage.PaymentsStore, payment *model.Payment, quote *orchestratorv1.PaymentQuote) error {
	s.ensureHandlers()
	return s.comp.executor.executePayment(ctx, store, payment, quote)
}

func (s *Service) resumePaymentPlan(ctx context.Context, store storage.PaymentsStore, payment *model.Payment) error {
	if payment == nil || payment.PaymentPlan == nil || len(payment.PaymentPlan.Steps) == 0 {
		return nil
	}
	s.ensureHandlers()
	return s.comp.executor.executePaymentPlan(ctx, store, payment, nil)
}

func (s *Service) releasePaymentHold(ctx context.Context, store storage.PaymentsStore, payment *model.Payment) error {
	if payment == nil || payment.PaymentPlan == nil || len(payment.PaymentPlan.Steps) == 0 {
		return nil
	}
	s.ensureHandlers()
	return s.comp.executor.releasePaymentHold(ctx, store, payment)
}