package facade

import (
	"log"

	"nearle/config"
	"nearle/controllers"
	"nearle/repositories"
	"nearle/services"
	"nearle/services/tools"
	"nearle/utils"

	"gorm.io/gorm"
)

type Facade struct {
	UserController            *controllers.UserController
	ProductController         *controllers.ProductController
	OrderController           *controllers.OrderController
	DeliveriesController      *controllers.DeliveriesController
	UtilsController           *controllers.UtilsController
	TenantController          *controllers.TenantController
	PartnerController         *controllers.PartnerController
	CustomerController        *controllers.CustomerController
	StockRequestController    *controllers.StockRequestController
	CatalogueController       *controllers.CatalogueController
	PosController             *controllers.PosController
	LiveController            *controllers.LiveController
	CatalogueUploadController *controllers.CatalogueUploadController
	ScanController            *controllers.ScanController
	AssistantController       *controllers.AssistantController
	HealthController          *controllers.HealthController
	MCPController             *controllers.MCPController

	// Tools is what Nearle Buddy is allowed to do.
	//
	// Held on the facade because the assistant is not a module with a
	// repository of its own — it is a door onto the services already built
	// here, and every tool handler calls one of them rather than the database.
	Tools *tools.Registry

	// Held so the NATS consumer can reach the ingest without going through
	// HTTP. Unexported: everything else should use the controller.
	posService services.PosService
}

// NewFacade wires up modules against the main (nearledb) connection.
// catalogueDB is a separate connection to the pgvector catalogue database;
// it may be nil if catalogue env vars are not configured, in which case
// catalogue endpoints will error at query time rather than at startup.
// embedder may be nil too: scan-to-order then matches on words alone.
func NewFacade(db *gorm.DB, catalogueDB *gorm.DB, embedder utils.Embedder, chat utils.Chat, agentsDir, assistantWhy string, mailer utils.Mailer, mailCfg config.MailConfig, nutritionBase string) *Facade {

	// The invitation, built first because two modules need it.
	//
	// Every back-office account on this platform is created with NO password —
	// the onboarded merchant, every person added to the directory, and the login
	// each branch spawns — and since the sign-in screen stopped offering to set
	// one, the emailed link is the only way in. So whichever module creates an
	// account has to be able to send it.
	//
	// `mailer` may be nil: a deployment with no mail configured still creates
	// everything, and each response says the invitation was not sent and names
	// the variable, rather than failing the create.
	//
	// The tenant repository supplies the business name for the mail's first line
	// (`services.TenantNamer`), which is why it is built here rather than in the
	// tenant module below.
	tenantRepo := repositories.NewTenantRepository(db)
	inviteService := services.NewInviteService(mailer, mailCfg, tenantRepo)

	// User Module
	userRepo := repositories.NewUserRepository(db)
	userService := services.NewUserService(userRepo, inviteService)
	userController := controllers.NewUserController(userService)

	// Catalogue Module (separate pgvector DB — never the main `db`). Built
	// before the Product Module because ProductService depends on it to
	// bridge catalogue imports into a tenant's own product catalogue.
	catalogueRepo := repositories.NewCatalogueRepository(catalogueDB)
	catalogueService := services.NewCatalogueService(catalogueRepo)
	catalogueController := controllers.NewCatalogueController(catalogueService)

	// Product Module
	//
	// The nutrition service is the catalogue-intelligence host — the same one
	// behind the health score card in the console — read by the product screen
	// for its nutrition panel. Nil when NUTRITION_BASE is unset, which serves
	// every product screen exactly as before, without a panel.
	productRepo := repositories.NewProductRepository(db)
	productService := services.NewProductService(
		productRepo, catalogueService, services.NewNutritionService(nutritionBase))
	productController := controllers.NewProductController(productService)

	// Order Module
	orderRepo := repositories.NewOrderRepository(db)
	orderService := services.NewOrderService(orderRepo)
	orderController := controllers.NewOrderController(orderService)

	// Deliveries Module
	deliveriesRepo := repositories.NewDeliveriesRepository(db)
	deliveriesService := services.NewDeliveriesService(deliveriesRepo)
	deliveriesController := controllers.NewDeliveriesController(deliveriesService)

	// Utils Module
	utilsRepo := repositories.NewUtilsRepository(db)
	utilsService := services.NewUtilsService(utilsRepo)
	utilsController := controllers.NewUtilsController(utilsService)

	//Tenant Module
	//
	// Onboarding, adding a person and commissioning a branch all create an
	// account with no password, so all three send an invitation. `tenantRepo` and
	// `inviteService` are built above, where the reasoning is.
	tenantService := services.NewTenantService(tenantRepo, inviteService)
	tenantController := controllers.NewTenantController(tenantService)

	//Partner Module
	partnerRepo := repositories.NewPartnerRepository(db)
	partnerService := services.NewPartnerService(partnerRepo)
	partnerController := controllers.NewPartnerController(partnerService)

	//Customer Module
	customerRepo := repositories.NewCustomerRepository(db)
	customerService := services.NewCustomerService(customerRepo)
	customerController := controllers.NewCustomerController(customerService)

	// Stock Request Module
	stockRequestRepo := repositories.NewStockRequestRepository(db)
	stockRequestService := services.NewStockRequestService(stockRequestRepo, productService)
	stockRequestController := controllers.NewStockRequestController(stockRequestService)

	// POS Module — ingest from the in-store terminals.
	//
	// Presence has no *gorm.DB: terminal health lives in Redis under a TTL, so
	// a till that loses power ages out of the board by itself instead of
	// leaving a Postgres row claiming it is online.
	posRepo := repositories.NewPosRepository(db)
	posPresence := repositories.NewPosPresenceRepository()
	posService := services.NewPosService(posRepo, posPresence)
	posController := controllers.NewPosController(posService)

	// Shares the POS service purely for its outlet-ownership check — the
	// stream itself reads no database and holds no state beyond its
	// subscribers.
	liveController := controllers.NewLiveController(posService)

	// Catalogue Upload Module — our own receipt for every spreadsheet sent to
	// the ingest service. Their host deletes an unreviewed drop after seven
	// days and the batch id is the only credential for reading the result
	// back, so the id has to be kept somewhere that outlives a browser tab.
	catalogueUploadRepo := repositories.NewCatalogueUploadRepository(db)
	catalogueUploadService := services.NewCatalogueUploadService(catalogueUploadRepo)
	catalogueUploadController := controllers.NewCatalogueUploadController(catalogueUploadService)

	// Scan Module — a label from the customer's camera to "buy it here".
	// Reads both databases: the catalogue to recognise the product, nearledb
	// for who the customer is and what their outlets have on the shelf.
	scanRepo := repositories.NewScanRepository(db, catalogueDB)
	scanService := services.NewScanService(scanRepo, embedder)
	scanController := controllers.NewScanController(scanService)

	// The assistant registry. Built last, because every tool it holds is a thin
	// wrapper over a service constructed above.
	//
	// A registration error panics rather than being logged. A duplicate name or
	// a tool with no description is a programming mistake, and a server that
	// starts with a tool silently absent answers real questions with "I cannot
	// do that" for a reason nobody can see from the outside.
	// The help corpus, checked before it is registered. A passage carrying one
	// shop's figures stops the server rather than reaching another shop's screen.
	helpCorpus, err := tools.LoadHelp()
	if err != nil {
		panic("assistant help: " + err.Error())
	}

	// The audit trail goes to the database and to the log. See
	// services/assistantAudit.go for why both.
	auditRepo := repositories.NewAssistantAuditRepository(db)
	toolRegistry := tools.New(services.NewDBAudit(auditRepo))
	for _, tool := range []tools.Tool{
		tools.StuckOrders(deliveriesService, nil),
		tools.DeliveryProgress(deliveriesService),
		tools.BranchPerformance(orderService),
		tools.PendingApprovals(stockRequestService, nil),
		tools.LowStock(productService),
		tools.TillsNotSyncing(posService),
		tools.SalesByChannel(orderService, posService, nil),
		tools.Help(helpCorpus),
		tools.ApproveStockRequest(stockRequestService, stockRequestService),
	} {
		if err := toolRegistry.Register(tool); err != nil {
			panic("assistant tools: " + err.Error())
		}
	}

	// Nearle Buddy. `chat` may be nil — a deployment with no model configured
	// still gets the registry and the endpoint, and the endpoint answers "not
	// switched on here" rather than a 500. The tools themselves are ordinary
	// Go functions and work either way; only turning a sentence into a tool
	// call needs a model.
	// Agent definitions, validated against the registry above. A typo in a tool
	// name stops the server rather than producing an agent that quietly cannot
	// do one of the things it claims — which is invisible at runtime, because the
	// model simply reports it could not look something up.
	agents, err := services.LoadAgents(agentsDir, toolRegistry.Has)
	if err != nil {
		panic("assistant agents: " + err.Error())
	}

	log.Printf("assistant: %d agents loaded %v", len(agents), services.AgentNames(agents))

	assistantService := services.NewAssistantService(toolRegistry, chat, agents)
	// Why there is no model, if there is not. Passed through so /assistant/status
	// can name the missing variable instead of just saying no.
	if setter, ok := assistantService.(interface{ SetUnavailableReason(string) }); ok && chat == nil {
		setter.SetUnavailableReason(assistantWhy)
	}
	assistantController := controllers.NewAssistantController(assistantService)

	// What is running here. Unauthenticated, booleans only — see healthController.go
	// for why a server that cannot say which build it is costs a day.
	healthController := controllers.NewHealthController(assistantService, db != nil)

	// The second door. Same registry, same agents, same session — see
	// controllers/mcpController.go for why it is a door rather than a service.
	mcpController := controllers.NewMCPController(toolRegistry, agents)

	return &Facade{
		UserController:            userController,
		ProductController:         productController,
		OrderController:           orderController,
		DeliveriesController:      deliveriesController,
		UtilsController:           utilsController,
		TenantController:          tenantController,
		PartnerController:         partnerController,
		CustomerController:        customerController,
		StockRequestController:    stockRequestController,
		CatalogueController:       catalogueController,
		PosController:             posController,
		LiveController:            liveController,
		CatalogueUploadController: catalogueUploadController,
		ScanController:            scanController,
		AssistantController:       assistantController,
		HealthController:          healthController,
		MCPController:             mcpController,
		Tools:                     toolRegistry,
		posService:                posService,
	}
}

// PosService exposes the ingest to callers outside the HTTP layer — the NATS
// consumer runs the same code path a POST does, so a bill arriving over MQTT
// and one arriving over HTTP cannot diverge.
func (f *Facade) PosService() services.PosService { return f.posService }