package api

import (
	"errors"
	"io"
	"net/http"
	"time"

	"bookra/apps/backend/internal/auth"
	"bookra/apps/backend/internal/billing"
	"bookra/apps/backend/internal/bookings"
	"bookra/apps/backend/internal/catalog"
	"bookra/apps/backend/internal/config"
	"bookra/apps/backend/internal/db"
	"bookra/apps/backend/internal/domain"
	"bookra/apps/backend/internal/httpx"
	"bookra/apps/backend/internal/notifications"
	"bookra/apps/backend/internal/tenancy"

	"github.com/gin-contrib/cors"
	"github.com/gin-gonic/gin"
	"golang.org/x/time/rate"
)

type Server struct {
	router   *gin.Engine
	cfg      config.Config
	pools    *db.Pools
	verifier *auth.Verifier
}

func NewServer(cfg config.Config, pools *db.Pools) (*Server, error) {
	verifier, err := auth.NewVerifier(cfg.NeonAuthURL)
	if err != nil {
		return nil, err
	}

	repository := db.NewRepository(pools)
	bookingService := bookings.NewService(repository)
	tenantService := tenancy.NewService(repository)
	billingService := billing.NewService(cfg, repository)
	notificationService := notifications.NewService(cfg, repository)
	publicRateLimiter := httpx.NewRateLimiter(rate.Every(time.Second), 5)

	server := &Server{
		router:   gin.New(),
		cfg:      cfg,
		pools:    pools,
		verifier: verifier,
	}

	server.router.Use(gin.Logger(), gin.Recovery(), cors.New(cors.Config{
		AllowOrigins:     []string{cfg.FrontendURL},
		AllowHeaders:     []string{"Authorization", "Content-Type"},
		AllowMethods:     []string{"GET", "POST", "OPTIONS"},
		AllowCredentials: true,
	}), httpx.SecurityHeaders())

	server.router.GET("/healthz", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{
			"status":             "ok",
			"environment":        cfg.Environment,
			"databaseConfigured": pools.DatabaseConfigured(),
		})
	})

	server.router.GET("/v1/meta/config", func(c *gin.Context) {
		c.JSON(http.StatusOK, gin.H{
			"environment":     cfg.Environment,
			"neonAuthEnabled": verifier.Enabled(),
			"apiUrl":          cfg.APIURL,
		})
	})

	server.router.GET("/v1/public/tenants/:tenantSlug/availability", func(c *gin.Context) {
		response, err := bookingService.Availability(c.Request.Context(), c.Param("tenantSlug"))
		if err != nil {
			status := http.StatusInternalServerError
			if errors.Is(err, bookings.ErrTenantNotFound) {
				status = http.StatusNotFound
			}
			c.JSON(status, gin.H{"error": err.Error()})
			return
		}
		c.JSON(http.StatusOK, response)
	})

	server.router.POST("/v1/public/bookings", publicRateLimiter.Middleware(), func(c *gin.Context) {
		var request struct {
			TenantSlug     string  `json:"tenantSlug" binding:"required"`
			BookingMode    string  `json:"bookingMode" binding:"required"`
			ServiceID      *string `json:"serviceId"`
			ClassSessionID *string `json:"classSessionId"`
			StaffID        *string `json:"staffId"`
			LocationID     *string `json:"locationId"`
			CustomerName   string  `json:"customerName" binding:"required"`
			CustomerEmail  string  `json:"customerEmail" binding:"required,email"`
			Notes          string  `json:"notes"`
			StartsAt       string  `json:"startsAt" binding:"required"`
			EndsAt         string  `json:"endsAt" binding:"required"`
		}
		if err := c.ShouldBindJSON(&request); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid_request"})
			return
		}

		response, err := bookingService.Create(c.Request.Context(), domain.CreateBookingRequest(request))
		if err != nil {
			status := http.StatusInternalServerError
			switch {
			case errors.Is(err, bookings.ErrInvalidBooking):
				status = http.StatusBadRequest
			case errors.Is(err, bookings.ErrTenantNotFound):
				status = http.StatusNotFound
			case errors.Is(err, bookings.ErrBookingConflict):
				status = http.StatusConflict
			}
			c.JSON(status, gin.H{"error": err.Error()})
			return
		}

		c.JSON(http.StatusCreated, response)
	})

	protected := server.router.Group("/v1")
	protected.Use(auth.RequireAuth(verifier, repository))

	protected.GET("/dashboard/summary", func(c *gin.Context) {
		response, err := bookingService.DashboardSummary(c.Request.Context(), auth.PrincipalFromContext(c))
		if err != nil {
			status := http.StatusInternalServerError
			if errors.Is(err, bookings.ErrTenantMembership) {
				status = http.StatusNotFound
			}
			c.JSON(status, gin.H{"error": err.Error()})
			return
		}
		c.JSON(http.StatusOK, response)
	})
	protected.GET("/tenants/bootstrap", func(c *gin.Context) {
		response, err := tenantService.Bootstrap(c.Request.Context(), auth.PrincipalFromContext(c))
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
			return
		}
		c.JSON(http.StatusOK, response)
	})
	protected.POST("/tenants/onboard", func(c *gin.Context) {
		var request domain.OnboardTenantRequest
		if err := c.ShouldBindJSON(&request); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid_request"})
			return
		}
		response, err := tenantService.Onboard(c.Request.Context(), auth.PrincipalFromContext(c), request)
		if err != nil {
			status := http.StatusInternalServerError
			switch {
			case errors.Is(err, tenancy.ErrInvalidOnboarding):
				status = http.StatusBadRequest
			case errors.Is(err, tenancy.ErrTenantAlreadyProvisioned), errors.Is(err, tenancy.ErrTenantSlugTaken):
				status = http.StatusConflict
			}
			c.JSON(status, gin.H{"error": err.Error()})
			return
		}
		c.JSON(http.StatusCreated, response)
	})

	_ = catalog.NewService()

	protected.GET("/billing/subscription", func(c *gin.Context) {
		response, err := billingService.GetSubscription(c.Request.Context(), auth.PrincipalFromContext(c))
		if err != nil {
			status := http.StatusInternalServerError
			if errors.Is(err, billing.ErrBillingMembership) {
				status = http.StatusNotFound
			}
			c.JSON(status, gin.H{"error": err.Error()})
			return
		}
		c.JSON(http.StatusOK, response)
	})
	protected.POST("/billing/checkout", func(c *gin.Context) {
		var request domain.CheckoutSessionRequest
		if err := c.ShouldBindJSON(&request); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid_request"})
			return
		}
		response, err := billingService.CreateCheckoutSession(c.Request.Context(), auth.PrincipalFromContext(c), request.PlanCode)
		if err != nil {
			status := http.StatusInternalServerError
			if errors.Is(err, billing.ErrBillingMembership) {
				status = http.StatusNotFound
			}
			if errors.Is(err, billing.ErrBillingPlanUnsupported) {
				status = http.StatusBadRequest
			}
			c.JSON(status, gin.H{"error": err.Error()})
			return
		}
		c.JSON(http.StatusOK, response)
	})
	protected.POST("/billing/refresh", func(c *gin.Context) {
		response, err := billingService.Refresh(c.Request.Context(), auth.PrincipalFromContext(c))
		if err != nil {
			status := http.StatusInternalServerError
			if errors.Is(err, billing.ErrBillingMembership) {
				status = http.StatusNotFound
			}
			c.JSON(status, gin.H{"error": err.Error()})
			return
		}
		c.JSON(http.StatusOK, response)
	})

	server.router.POST("/v1/webhooks/stripe", func(c *gin.Context) {
		payload, err := c.GetRawData()
		if err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid_payload"})
			return
		}
		if err := billingService.HandleWebhook(c.Request.Context(), c.GetHeader("Stripe-Signature"), payload); err != nil {
			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
			return
		}
		c.JSON(http.StatusOK, gin.H{"status": "accepted"})
	})

	server.router.POST("/v1/internal/jobs/reminders/dispatch", func(c *gin.Context) {
		if !authorizeJobRunner(c, cfg) {
			c.JSON(http.StatusUnauthorized, gin.H{"error": "unauthorized"})
			return
		}

		var request domain.DispatchReminderJobsRequest
		if err := c.ShouldBindJSON(&request); err != nil && !errors.Is(err, io.EOF) {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid_request"})
			return
		}

		response, err := notificationService.DispatchDue(c.Request.Context(), request.Limit)
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
			return
		}
		c.JSON(http.StatusOK, response)
	})

	return server, nil
}

func (s *Server) Handler() http.Handler {
	return s.router
}

func authorizeJobRunner(c *gin.Context, cfg config.Config) bool {
	if cfg.JobRunnerKey == "" {
		return cfg.Environment == "development"
	}
	return c.GetHeader("X-Bookra-Job-Key") == cfg.JobRunnerKey
}