package handler

import (
	"baron-sso-backend/internal/domain"
	"baron-sso-backend/internal/repository"
	"baron-sso-backend/internal/service"
	"errors"
	"strings"
	"time"

	"github.com/gofiber/fiber/v2"
	"gorm.io/gorm"
)

type TenantHandler struct {
	DB          *gorm.DB
	Service     service.TenantService
	Keto        service.KetoService
	KratosAdmin *service.KratosAdminService
}

func NewTenantHandler(db *gorm.DB, svc service.TenantService, keto service.KetoService, kratos *service.KratosAdminService) *TenantHandler {
	return &TenantHandler{
		DB:          db,
		Service:     svc,
		Keto:        keto,
		KratosAdmin: kratos,
	}
}

type tenantSummary struct {
	ID          string         `json:"id"`
	Name        string         `json:"name"`
	Slug        string         `json:"slug"`
	Description string         `json:"description"`
	Status      string         `json:"status"`
	Domains     []string       `json:"domains,omitempty"`
	Config      domain.JSONMap `json:"config,omitempty"`
	CreatedAt   string         `json:"createdAt"`
	UpdatedAt   string         `json:"updatedAt"`
}

type tenantListResponse struct {
	Items  []tenantSummary `json:"items"`
	Limit  int             `json:"limit"`
	Offset int             `json:"offset"`
	Total  int64           `json:"total"`
}

func (h *TenantHandler) RegisterTenantPublic(c *fiber.Ctx) error {
	var req struct {
		Name        string `json:"name"`
		Slug        string `json:"slug"`
		Description string `json:"description"`
		Domain      string `json:"domain"`
		AdminEmail  string `json:"adminEmail"`
	}
	if err := c.BodyParser(&req); err != nil {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "invalid request body"})
	}

	// Basic validation
	if req.Name == "" || req.Domain == "" || req.AdminEmail == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "name, domain, and adminEmail are required"})
	}

	tenant, err := h.Service.RequestRegistration(c.Context(), req.Name, req.Slug, req.Description, req.Domain, req.AdminEmail)
	if err != nil {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": err.Error()})
	}

	return c.Status(fiber.StatusAccepted).JSON(fiber.Map{
		"message": "Registration request received and is pending approval.",
		"tenant":  mapTenantSummary(*tenant),
	})
}

func (h *TenantHandler) ApproveTenant(c *fiber.Ctx) error {
	tenantID := c.Params("id")
	if tenantID == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "tenant id is required"})
	}

	if err := h.Service.ApproveTenant(c.Context(), tenantID); err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	return c.JSON(fiber.Map{"message": "Tenant approved successfully"})
}

func (h *TenantHandler) ListTenants(c *fiber.Ctx) error {
	if h.DB == nil {
		return c.Status(fiber.StatusServiceUnavailable).JSON(fiber.Map{"error": "database not available"})
	}

	limit := c.QueryInt("limit", 50)
	offset := c.QueryInt("offset", 0)
	if limit <= 0 {
		limit = 50
	}
	if offset < 0 {
		offset = 0
	}

	var total int64
	if err := h.DB.Model(&domain.Tenant{}).Count(&total).Error; err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	var tenants []domain.Tenant
	if err := h.DB.Order("created_at desc").Limit(limit).Offset(offset).Preload("Domains").Find(&tenants).Error; err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	items := make([]tenantSummary, 0, len(tenants))
	for _, t := range tenants {
		items = append(items, mapTenantSummary(t))
	}

	return c.JSON(tenantListResponse{Items: items, Limit: limit, Offset: offset, Total: total})
}

func (h *TenantHandler) GetTenant(c *fiber.Ctx) error {
	if h.DB == nil {
		return c.Status(fiber.StatusServiceUnavailable).JSON(fiber.Map{"error": "database not available"})
	}

	tenantID := strings.TrimSpace(c.Params("id"))
	if tenantID == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "tenant id is required"})
	}

	var tenant domain.Tenant
	if err := h.DB.Preload("Domains").First(&tenant, "id = ?", tenantID).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return c.Status(fiber.StatusNotFound).JSON(fiber.Map{"error": "tenant not found"})
		}
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	return c.JSON(mapTenantSummary(tenant))
}

func (h *TenantHandler) CreateTenant(c *fiber.Ctx) error {
	if h.DB == nil {
		return c.Status(fiber.StatusServiceUnavailable).JSON(fiber.Map{"error": "database not available"})
	}

	var req struct {
		Name        string         `json:"name"`
		Slug        string         `json:"slug"`
		Description string         `json:"description"`
		Status      string         `json:"status"`
		Domains     []string       `json:"domains"`
		Config      map[string]any `json:"config"`
	}
	if err := c.BodyParser(&req); err != nil {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "invalid request body"})
	}

	name := strings.TrimSpace(req.Name)
	if name == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "name is required"})
	}

	slug := normalizeTenantSlug(req.Slug)
	if slug == "" {
		slug = normalizeTenantSlug(name)
	}
	if slug == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "slug is required"})
	}

	status := normalizeTenantStatus(req.Status)
	if status == "" {
		status = "active"
	}

	// Use Service
	tenant, err := h.Service.RegisterTenant(c.Context(), name, slug, req.Description, req.Domains)
	if err != nil {
		if strings.Contains(err.Error(), "already exists") {
			return c.Status(fiber.StatusConflict).JSON(fiber.Map{"error": err.Error()})
		}
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	if req.Config != nil {
		tenant.Config = req.Config
		h.DB.Save(tenant)
	}

	return c.Status(fiber.StatusCreated).JSON(mapTenantSummary(*tenant))
}

func (h *TenantHandler) UpdateTenant(c *fiber.Ctx) error {
	if h.DB == nil {
		return c.Status(fiber.StatusServiceUnavailable).JSON(fiber.Map{"error": "database not available"})
	}

	tenantID := strings.TrimSpace(c.Params("id"))
	if tenantID == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "tenant id is required"})
	}

	var tenant domain.Tenant
	if err := h.DB.First(&tenant, "id = ?", tenantID).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return c.Status(fiber.StatusNotFound).JSON(fiber.Map{"error": "tenant not found"})
		}
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	var req struct {
		Name        *string        `json:"name"`
		Slug        *string        `json:"slug"`
		Description *string        `json:"description"`
		Status      *string        `json:"status"`
		Domains     []string       `json:"domains"`
		Config      map[string]any `json:"config"`
	}
	if err := c.BodyParser(&req); err != nil {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "invalid request body"})
	}

	if req.Name != nil {
		name := strings.TrimSpace(*req.Name)
		if name == "" {
			return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "name cannot be empty"})
		}
		tenant.Name = name
	}
	if req.Slug != nil {
		slug := normalizeTenantSlug(*req.Slug)
		if slug == "" {
			return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "slug cannot be empty"})
		}
		if slug != tenant.Slug {
			var exists domain.Tenant
			if err := h.DB.Unscoped().Where("slug = ?", slug).First(&exists).Error; err == nil {
				return c.Status(fiber.StatusConflict).JSON(fiber.Map{"error": "slug already exists"})
			} else if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
				return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
			}
			tenant.Slug = slug
		}
	}
	if req.Description != nil {
		tenant.Description = strings.TrimSpace(*req.Description)
	}
	if req.Status != nil {
		status := normalizeTenantStatus(*req.Status)
		if status == "" {
			return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "status must be active or inactive"})
		}
		tenant.Status = status
	}
	if req.Config != nil {
		tenant.Config = req.Config
	}

	if err := h.DB.Save(&tenant).Error; err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	// Update domains if provided
	if req.Domains != nil {
		// Simple approach: Delete existing and recreate
		if err := h.DB.Delete(&domain.TenantDomain{}, "tenant_id = ?", tenant.ID).Error; err != nil {
			return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": "failed to clear old domains"})
		}
		for _, d := range req.Domains {
			if strings.TrimSpace(d) == "" {
				continue
			}
			// Use repository for consistency
			if err := repository.NewTenantRepository(h.DB).AddDomain(c.Context(), tenant.ID, strings.TrimSpace(d), true); err != nil {
				return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": "failed to add domain: " + d})
			}
		}
	}

	// Refetch to get updated relations
	h.DB.Preload("Domains").First(&tenant, "id = ?", tenant.ID)

	return c.JSON(mapTenantSummary(tenant))
}

func (h *TenantHandler) DeleteTenant(c *fiber.Ctx) error {
	if h.DB == nil {
		return c.Status(fiber.StatusServiceUnavailable).JSON(fiber.Map{"error": "database not available"})
	}

	tenantID := strings.TrimSpace(c.Params("id"))
	if tenantID == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "tenant id is required"})
	}

	var tenant domain.Tenant
	if err := h.DB.First(&tenant, "id = ?", tenantID).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return c.Status(fiber.StatusNotFound).JSON(fiber.Map{"error": "tenant not found"})
		}
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	// Rename slug to release it for reuse before soft delete
	deletedSlug := tenant.Slug + "-deleted-" + time.Now().Format("20060102150405")
	if err := h.DB.Model(&tenant).Update("slug", deletedSlug).Error; err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": "failed to release slug"})
	}

	if err := h.DB.Delete(&tenant).Error; err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	return c.SendStatus(fiber.StatusNoContent)
}

func (h *TenantHandler) ListAdmins(c *fiber.Ctx) error {
	tenantID := c.Params("id")
	if tenantID == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "tenant id is required"})
	}

	// Fetch admins from Keto
	relations, err := h.Keto.ListRelations(c.Context(), "Tenant", tenantID, "admin", "")
	if err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	type adminInfo struct {
		ID    string `json:"id"`
		Name  string `json:"name"`
		Email string `json:"email"`
	}
	admins := []adminInfo{}

	for _, rel := range relations {
		if !strings.HasPrefix(rel.SubjectID, "User:") {
			continue
		}
		userID := strings.TrimPrefix(rel.SubjectID, "User:")

		// Fetch user details from Kratos
		identity, err := h.KratosAdmin.GetIdentity(c.Context(), userID)
		if err != nil {
			admins = append(admins, adminInfo{ID: userID, Name: "Unknown", Email: "Unknown"})
			continue
		}

		name := ""
		if n, ok := identity.Traits["name"].(string); ok {
			name = n
		}
		email := ""
		if e, ok := identity.Traits["email"].(string); ok {
			email = e
		}

		admins = append(admins, adminInfo{
			ID:    userID,
			Name:  name,
			Email: email,
		})
	}

	return c.JSON(admins)
}

func (h *TenantHandler) AddAdmin(c *fiber.Ctx) error {
	tenantID := c.Params("id")
	userID := c.Params("userId")
	if tenantID == "" || userID == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "tenantId and userId are required"})
	}

	if err := h.Keto.CreateRelation(c.Context(), "Tenant", tenantID, "admin", "User:"+userID); err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	return c.SendStatus(fiber.StatusOK)
}

func (h *TenantHandler) RemoveAdmin(c *fiber.Ctx) error {
	tenantID := c.Params("id")
	userID := c.Params("userId")
	if tenantID == "" || userID == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "tenantId and userId are required"})
	}

	if err := h.Keto.DeleteRelation(c.Context(), "Tenant", tenantID, "admin", "User:"+userID); err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	return c.SendStatus(fiber.StatusNoContent)
}

func mapTenantSummary(t domain.Tenant) tenantSummary {
	domains := make([]string, 0, len(t.Domains))
	for _, d := range t.Domains {
		domains = append(domains, d.Domain)
	}

	return tenantSummary{
		ID:          t.ID,
		Name:        t.Name,
		Slug:        t.Slug,
		Description: t.Description,
		Status:      t.Status,
		Domains:     domains,
		Config:      t.Config,
		CreatedAt:   t.CreatedAt.Format(time.RFC3339),
		UpdatedAt:   t.UpdatedAt.Format(time.RFC3339),
	}
}

func normalizeTenantSlug(value string) string {
	value = strings.ToLower(strings.TrimSpace(value))
	value = strings.ReplaceAll(value, " ", "-")
	var b strings.Builder
	for _, r := range value {
		if (r >= 'a' && r <= 'z') || (r >= '0' && r <= '9') || r == '-' {
			b.WriteRune(r)
		}
	}
	return strings.Trim(b.String(), "-")
}

func normalizeTenantStatus(value string) string {
	value = strings.ToLower(strings.TrimSpace(value))
	if value == "" {
		return ""
	}
	if value != "active" && value != "inactive" {
		return ""
	}
	return value
}