package v1

// ContactMergeHandler provides HTTP handler for merging two contacts.
// Reference: Chatwoot app/controllers/api/v1/accounts/actions/contact_merges_controller.rb
//
// Routes:
//   POST /api/v1/accounts/:account_id/actions/contact_merges -> Create
//
// Request body:
//   { "base_contact_id": 1, "mergee_contact_id": 2 }
//
// Chatwoot's response: returns the base contact after merge on success, 200 OK

import (
	"net/http"
	"strconv"

	"github.com/gin-gonic/gin"
	"github.com/gochat/gochat/internal/model"
	"github.com/gochat/gochat/internal/service"
	"github.com/gochat/gochat/pkg/response"
)

// ContactMergeHandler handles HTTP requests for contact merge operations.
type ContactMergeHandler struct {
	mergeService *service.ContactMergeService
}

// NewContactMergeHandler creates a new ContactMergeHandler.
func NewContactMergeHandler(mergeService *service.ContactMergeService) *ContactMergeHandler {
	return &ContactMergeHandler{mergeService: mergeService}
}

// Create merges the mergee contact into the base contact.
// Reference: Chatwoot `def create`
//
//	contact_merge_action = ContactMergeAction.new(
//	  account: Current.account,
//	  base_contact: @base_contact,
//	  mergee_contact: @mergee_contact
//	)
//	contact_merge_action.perform
//
// Chatwoot returns the base contact on success with 200 OK.
func (h *ContactMergeHandler) Create(c *gin.Context) {
	accountID, err := strconv.ParseUint(c.Param("account_id"), 10, 64)
	if err != nil {
		response.AbortWithStatusError(c, 400, response.ErrBadRequest, "Invalid account ID")
		return
	}

	var req model.ContactMergeRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.AbortWithStatusError(c, 400, response.ErrBadRequest, "base_contact_id and mergee_contact_id are required")
		return
	}

	contact, err := h.mergeService.Merge(uint(accountID), req.BaseContactID, req.MergeeContactID)
	if err != nil {
		if err == service.ErrMergeSameContact {
			response.AbortWithStatusError(c, 400, response.ErrBadRequest, "Cannot merge the same contact")
			return
		}
		if err == service.ErrMergeBaseNotFound {
			response.AbortWithStatusError(c, 404, response.ErrContactNotFound, "Base contact not found")
			return
		}
		if err == service.ErrMergeeNotFound {
			response.AbortWithStatusError(c, 404, response.ErrContactNotFound, "Mergee contact not found")
			return
		}
		if err == service.ErrMergeNotInAccount {
			response.AbortWithStatusError(c, 403, response.ErrForbidden, "Contact does not belong to the account")
			return
		}
		response.AbortWithStatusError(c, 500, response.ErrInternal, "Failed to merge contacts")
		return
	}

	c.JSON(http.StatusOK, serializeCRMContact(c.Request.Context(), nil, contact, false))
}