package handlers

import (
	"net/http"

	"veza-backend-api/internal/models"
	"veza-backend-api/internal/repositories"
	apperrors "veza-backend-api/internal/errors"

	chatws "veza-backend-api/internal/websocket/chat"

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
	"go.uber.org/zap"
)

// ChatReactionHandler handles REST API for chat message reactions (v0.9.6)
type ChatReactionHandler struct {
	reactionRepo *repositories.ReactionRepository
	msgRepo      *repositories.ChatMessageRepository
	permissions  *chatws.PermissionService
	logger       *zap.Logger
}

// NewChatReactionHandler creates a new ChatReactionHandler
func NewChatReactionHandler(
	reactionRepo *repositories.ReactionRepository,
	msgRepo *repositories.ChatMessageRepository,
	permissions *chatws.PermissionService,
	logger *zap.Logger,
) *ChatReactionHandler {
	if logger == nil {
		logger = zap.NewNop()
	}
	return &ChatReactionHandler{
		reactionRepo: reactionRepo,
		msgRepo:      msgRepo,
		permissions:  permissions,
		logger:       logger,
	}
}

// AddReactionRequest body for POST
type AddReactionRequest struct {
	Emoji string `json:"emoji" binding:"required" validate:"required,max=50"`
}

// AddReaction adds a reaction to a message
// POST /api/v1/chat/rooms/:roomId/messages/:messageId/reactions
func (h *ChatReactionHandler) AddReaction(c *gin.Context) {
	userID, ok := GetUserIDUUID(c)
	if !ok {
		return
	}

	roomID, err := uuid.Parse(c.Param("roomId"))
	if err != nil {
		RespondWithAppError(c, apperrors.NewValidationError("Invalid room ID"))
		return
	}
	messageID, err := uuid.Parse(c.Param("messageId"))
	if err != nil {
		RespondWithAppError(c, apperrors.NewValidationError("Invalid message ID"))
		return
	}

	if !h.permissions.CanRead(c.Request.Context(), userID, roomID) {
		RespondWithAppError(c, apperrors.NewForbiddenError("Not allowed to access this conversation"))
		return
	}

	var req AddReactionRequest
	if err := c.ShouldBindJSON(&req); err != nil || req.Emoji == "" {
		RespondWithAppError(c, apperrors.NewValidationError("emoji is required"))
		return
	}

	msg, err := h.msgRepo.GetByID(c.Request.Context(), messageID)
	if err != nil {
		RespondWithAppError(c, apperrors.NewNotFoundError("Message"))
		return
	}
	if msg.ConversationID != roomID {
		RespondWithAppError(c, apperrors.NewValidationError("Message does not belong to this room"))
		return
	}

	reaction := &models.MessageReaction{
		ID:        uuid.New(),
		UserID:    userID,
		MessageID: messageID,
		Emoji:     req.Emoji,
	}
	if err := h.reactionRepo.Add(c.Request.Context(), reaction); err != nil {
		h.logger.Error("Failed to add reaction", zap.Error(err))
		RespondWithAppError(c, apperrors.NewInternalErrorWrap("Failed to add reaction", err))
		return
	}

	RespondSuccess(c, http.StatusCreated, gin.H{
		"reaction": gin.H{
			"id":         reaction.ID,
			"user_id":    reaction.UserID,
			"message_id": reaction.MessageID,
			"emoji":      reaction.Emoji,
		},
	})
}

// RemoveReaction removes a reaction from a message
// DELETE /api/v1/chat/rooms/:roomId/messages/:messageId/reactions?emoji=👍
func (h *ChatReactionHandler) RemoveReaction(c *gin.Context) {
	userID, ok := GetUserIDUUID(c)
	if !ok {
		return
	}

	roomID, err := uuid.Parse(c.Param("roomId"))
	if err != nil {
		RespondWithAppError(c, apperrors.NewValidationError("Invalid room ID"))
		return
	}
	messageID, err := uuid.Parse(c.Param("messageId"))
	if err != nil {
		RespondWithAppError(c, apperrors.NewValidationError("Invalid message ID"))
		return
	}

	if !h.permissions.CanRead(c.Request.Context(), userID, roomID) {
		RespondWithAppError(c, apperrors.NewForbiddenError("Not allowed to access this conversation"))
		return
	}

	msg, err := h.msgRepo.GetByID(c.Request.Context(), messageID)
	if err != nil {
		RespondWithAppError(c, apperrors.NewNotFoundError("Message"))
		return
	}
	if msg.ConversationID != roomID {
		RespondWithAppError(c, apperrors.NewValidationError("Message does not belong to this room"))
		return
	}

	emoji := c.Query("emoji")
	if emoji != "" {
		err = h.reactionRepo.RemoveByEmoji(c.Request.Context(), userID, messageID, emoji)
	} else {
		err = h.reactionRepo.Remove(c.Request.Context(), userID, messageID)
	}
	if err != nil {
		h.logger.Error("Failed to remove reaction", zap.Error(err))
		RespondWithAppError(c, apperrors.NewInternalErrorWrap("Failed to remove reaction", err))
		return
	}

	RespondSuccess(c, http.StatusOK, gin.H{"success": true})
}