package handler

import (
	"net/http"

	"github.com/gin-gonic/gin"
	"kefu-sys/server/internal/middleware"
	"kefu-sys/server/internal/model"
)

type CustomerHandler struct{}

func NewCustomerHandler() *CustomerHandler { return &CustomerHandler{} }

func canAccessCustomer(c *gin.Context, customerID uint) bool {
	if middleware.HasAnyRole(c, "admin", "supervisor") {
		return true
	}
	if middleware.GetRole(c) != "agent" {
		return false
	}
	var count int64
	model.DB.Model(&model.Session{}).
		Where("tenant_id = ? AND customer_id = ? AND agent_id = ?", middleware.GetTenantID(c), customerID, middleware.GetUserID(c)).
		Count(&count)
	return count > 0
}

func (h *CustomerHandler) List(c *gin.Context) {
	tenantID := middleware.GetTenantID(c)
	page, pageSize := middleware.GetPageParams(c)
	search := c.Query("search")
	status := c.Query("status")
	source := c.Query("source")

	var customers []model.Customer
	var total int64

	query := model.DB.Where("tenant_id = ?", tenantID)
	if middleware.GetRole(c) == "agent" {
		assignedCustomers := model.DB.Model(&model.Session{}).
			Select("customer_id").
			Where("tenant_id = ? AND agent_id = ?", tenantID, middleware.GetUserID(c))
		query = query.Where("id IN (?)", assignedCustomers)
	}
	if search != "" {
		query = query.Where("name LIKE ? OR phone LIKE ? OR email LIKE ?", "%"+search+"%", "%"+search+"%", "%"+search+"%")
	}
	if status != "" {
		query = query.Where("status = ?", status)
	}
	if source != "" {
		query = query.Where("source = ?", source)
	}

	query.Model(&model.Customer{}).Count(&total)
	query.Order("updated_at desc").Offset((page - 1) * pageSize).Limit(pageSize).Find(&customers)

	middleware.JSONList(c, customers, total, page, pageSize)
}

func (h *CustomerHandler) Get(c *gin.Context) {
	tenantID := middleware.GetTenantID(c)
	id := c.Param("id")

	var customer model.Customer
	if err := model.DB.Where("id = ? AND tenant_id = ?", id, tenantID).First(&customer).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"code": 404, "message": "客户不存在"})
		return
	}
	if !canAccessCustomer(c, customer.ID) {
		c.JSON(http.StatusForbidden, gin.H{"code": 403, "message": "无权查看该客户"})
		return
	}

	var sessions []model.Session
	sessionQuery := model.DB.Where("customer_id = ? AND tenant_id = ?", customer.ID, tenantID)
	if middleware.GetRole(c) == "agent" {
		sessionQuery = sessionQuery.Where("agent_id = ?", middleware.GetUserID(c))
	}
	sessionQuery.Order("created_at desc").Limit(20).Find(&sessions)

	middleware.JSON(c, gin.H{"customer": customer, "sessions": sessions})
}

func (h *CustomerHandler) Create(c *gin.Context) {
	var customer model.Customer
	if err := c.ShouldBindJSON(&customer); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "参数错误"})
		return
	}

	customer.TenantID = middleware.GetTenantID(c)

	if err := model.DB.Create(&customer).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 500, "message": "创建失败"})
		return
	}

	middleware.JSON(c, customer)
}

func (h *CustomerHandler) Update(c *gin.Context) {
	tenantID := middleware.GetTenantID(c)
	id := c.Param("id")

	var customer model.Customer
	if err := model.DB.Where("id = ? AND tenant_id = ?", id, tenantID).First(&customer).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"code": 404, "message": "客户不存在"})
		return
	}
	if !canAccessCustomer(c, customer.ID) {
		c.JSON(http.StatusForbidden, gin.H{"code": 403, "message": "无权编辑该客户"})
		return
	}

	var updates map[string]interface{}
	if err := c.ShouldBindJSON(&updates); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "参数错误"})
		return
	}

	allowed := map[string]bool{"name": true, "phone": true, "email": true, "tags": true, "source": true, "status": true}
	for key := range updates {
		if !allowed[key] {
			delete(updates, key)
		}
	}
	if len(updates) == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"code": 400, "message": "没有可更新字段"})
		return
	}

	if err := model.DB.Model(&customer).Updates(updates).Error; err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"code": 500, "message": "更新失败"})
		return
	}
	model.DB.First(&customer, customer.ID)
	middleware.JSON(c, customer)
}

func (h *CustomerHandler) Delete(c *gin.Context) {
	if !middleware.HasAnyRole(c, "admin", "supervisor") {
		c.JSON(http.StatusForbidden, gin.H{"code": 403, "message": "仅主管或管理员可删除客户"})
		return
	}
	tenantID := middleware.GetTenantID(c)
	id := c.Param("id")

	result := model.DB.Where("id = ? AND tenant_id = ?", id, tenantID).Delete(&model.Customer{})
	if result.RowsAffected == 0 {
		c.JSON(http.StatusNotFound, gin.H{"code": 404, "message": "客户不存在"})
		return
	}

	middleware.JSON(c, gin.H{"message": "已删除"})
}