package v1

import (
	"net/http"
	"strconv"

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

// LabelHandler handles Tag CRUD and conversation-label association endpoints.
type LabelHandler struct {
	tagSvc   *service.TagService
	labelSvc *service.LabelService
}

func NewLabelHandler(tagSvc *service.TagService, labelSvc *service.LabelService) *LabelHandler {
	return &LabelHandler{tagSvc: tagSvc, labelSvc: labelSvc}
}

// ========== Tag CRUD ==========

// CreateTag creates a new tag/label in an account.
// POST /api/v1/accounts/:account_id/tags
func (h *LabelHandler) CreateTag(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	var req service.CreateTagRequest
	if err := bindJSONWrappedOrRaw(c, "label", &req); err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, err.Error())
		return
	}

	tag, err := h.tagSvc.Create(c.Request.Context(), accountID, &req)
	if err != nil {
		applogger.L().Errorf("Create tag: %v", err)
		handleServiceError(c, err)
		return
	}

	c.JSON(http.StatusOK, serializeLabel(tag))
}

// GetTag retrieves a tag by ID.
// GET /api/v1/accounts/:account_id/tags/:tag_id
func (h *LabelHandler) GetTag(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}
	tagID, err := parseUintParam(c, "tag_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid tag_id")
		return
	}

	tag, err := h.tagSvc.GetByIDAndAccountID(c.Request.Context(), accountID, tagID)
	if err != nil {
		applogger.L().Errorf("Get tag: %v", err)
		handleServiceError(c, err)
		return
	}

	c.JSON(http.StatusOK, serializeLabel(tag))
}

// ListTags returns all tags in an account.
// GET /api/v1/accounts/:account_id/tags
func (h *LabelHandler) ListTags(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	tags, err := h.tagSvc.List(c.Request.Context(), accountID)
	if err != nil {
		applogger.L().Errorf("List tags: %v", err)
		handleServiceError(c, err)
		return
	}

	c.JSON(http.StatusOK, gin.H{"payload": serializeLabels(tags)})
}

// UpdateTag modifies an existing tag.
// PUT /api/v1/accounts/:account_id/tags/:tag_id
func (h *LabelHandler) UpdateTag(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}
	tagID, err := parseUintParam(c, "tag_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid tag_id")
		return
	}

	if _, err := h.tagSvc.GetByIDAndAccountID(c.Request.Context(), accountID, tagID); err != nil {
		applogger.L().Errorf("Get tag for update: %v", err)
		handleServiceError(c, err)
		return
	}

	var req service.UpdateTagRequest
	if err := bindJSONWrappedOrRaw(c, "label", &req); err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, err.Error())
		return
	}

	tag, err := h.tagSvc.Update(c.Request.Context(), tagID, &req)
	if err != nil {
		applogger.L().Errorf("Update tag: %v", err)
		handleServiceError(c, err)
		return
	}

	c.JSON(http.StatusOK, serializeLabel(tag))
}

// DeleteTag soft-deletes a tag.
// DELETE /api/v1/accounts/:account_id/tags/:tag_id
func (h *LabelHandler) DeleteTag(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}
	tagID, err := parseUintParam(c, "tag_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid tag_id")
		return
	}

	if _, err := h.tagSvc.GetByIDAndAccountID(c.Request.Context(), accountID, tagID); err != nil {
		applogger.L().Errorf("Get tag for delete: %v", err)
		handleServiceError(c, err)
		return
	}

	if err := h.tagSvc.Delete(c.Request.Context(), tagID); err != nil {
		applogger.L().Errorf("Delete tag: %v", err)
		handleServiceError(c, err)
		return
	}

	c.Status(http.StatusOK)
}

func serializeLabels(tags []model.Tag) []gin.H {
	payload := make([]gin.H, 0, len(tags))
	for i := range tags {
		payload = append(payload, serializeLabel(&tags[i]))
	}
	return payload
}

func serializeLabel(tag *model.Tag) gin.H {
	return gin.H{
		"id":              tag.ID,
		"title":           tag.Name,
		"description":     tag.Description,
		"color":           tag.Color,
		"show_on_sidebar": labelShowOnSidebar(tag),
	}
}

func labelShowOnSidebar(tag *model.Tag) bool {
	if tag.ShowOnSidebar == nil {
		return false
	}
	return *tag.ShowOnSidebar
}

// ========== Conversation-Label Association ==========

// AddLabelToConversation attaches a label to a conversation.
// POST /api/v1/accounts/:account_id/conversations/:id/labels
func (h *LabelHandler) AddLabelToConversation(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}
	conversationID, err := parseUintParam(c, "id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid conversation id")
		return
	}

	var req struct {
		TagID uint `json:"tag_id" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, err.Error())
		return
	}

	cl, err := h.labelSvc.AddLabelToConversation(c.Request.Context(), accountID, conversationID, req.TagID)
	if err != nil {
		applogger.L().Errorf("Add label to conversation: %v", err)
		handleServiceError(c, err)
		return
	}

	response.Created(c, cl)
}

// RemoveLabelFromConversation detaches a label from a conversation.
// DELETE /api/v1/accounts/:account_id/conversations/:id/labels/:tag_id
func (h *LabelHandler) RemoveLabelFromConversation(c *gin.Context) {
	conversationID, err := parseUintParam(c, "id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid conversation id")
		return
	}
	tagID, err := parseUintParam(c, "tag_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid tag_id")
		return
	}

	if err := h.labelSvc.RemoveLabelFromConversation(c.Request.Context(), conversationID, tagID); err != nil {
		applogger.L().Errorf("Remove label from conversation: %v", err)
		handleServiceError(c, err)
		return
	}

	response.NoContent(c)
}

// GetConversationLabels returns all labels on a conversation.
// GET /api/v1/accounts/:account_id/conversations/:id/labels
func (h *LabelHandler) GetConversationLabels(c *gin.Context) {
	conversationID, err := parseUintParam(c, "id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid conversation id")
		return
	}

	labels, err := h.labelSvc.GetConversationLabels(c.Request.Context(), conversationID)
	if err != nil {
		applogger.L().Errorf("Get conversation labels: %v", err)
		handleServiceError(c, err)
		return
	}

	response.OK(c, labels)
}

// ReplaceConversationLabels replaces all labels on a conversation (Chatwoot-style).
// PATCH /api/v1/accounts/:account_id/conversations/:id/labels
func (h *LabelHandler) ReplaceConversationLabels(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}
	conversationID, err := parseUintParam(c, "id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid conversation id")
		return
	}

	var req struct {
		TagIDs []uint `json:"tag_ids"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, err.Error())
		return
	}

	labels, err := h.labelSvc.ReplaceConversationLabels(c.Request.Context(), accountID, conversationID, req.TagIDs)
	if err != nil {
		applogger.L().Errorf("Replace conversation labels: %v", err)
		handleServiceError(c, err)
		return
	}

	response.OK(c, labels)
}

// ========== Batch Label Operations ==========

// BatchAddLabel attaches a label to multiple conversations.
// POST /api/v1/accounts/:account_id/labels/batch_add
func (h *LabelHandler) BatchAddLabel(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	var req service.BatchAddLabelRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, err.Error())
		return
	}

	if err := h.labelSvc.BatchAddLabel(c.Request.Context(), accountID, &req); err != nil {
		applogger.L().Errorf("Batch add label: %v", err)
		handleServiceError(c, err)
		return
	}

	response.NoContent(c)
}

// BatchRemoveLabel detaches a label from multiple conversations.
// POST /api/v1/accounts/:account_id/labels/batch_remove
func (h *LabelHandler) BatchRemoveLabel(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	var req service.BatchRemoveLabelRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, err.Error())
		return
	}

	if err := h.labelSvc.BatchRemoveLabel(c.Request.Context(), accountID, &req); err != nil {
		applogger.L().Errorf("Batch remove label: %v", err)
		handleServiceError(c, err)
		return
	}

	response.NoContent(c)
}

// ========== Conversations by Tag ==========

// GetConversationsByTag returns all conversations that have a specific tag.
// GET /api/v1/accounts/:account_id/tags/:tag_id/conversations
func (h *LabelHandler) GetConversationsByTag(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}
	tagID, err := parseUintParam(c, "tag_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid tag_id")
		return
	}

	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	perPage, _ := strconv.Atoi(c.DefaultQuery("per_page", "25"))
	if page < 1 {
		page = 1
	}
	if perPage < 1 || perPage > 100 {
		perPage = 25
	}

	labels, count, err := h.labelSvc.GetConversationsByTag(c.Request.Context(), accountID, tagID, page, perPage)
	if err != nil {
		applogger.L().Errorf("Get conversations by tag: %v", err)
		handleServiceError(c, err)
		return
	}

	response.OK(c, gin.H{
		"labels":   labels,
		"count":    count,
		"page":     page,
		"per_page": perPage,
	})
}