package handlers

import (
	"encoding/json"
	"log"
	"net/http"
	"strconv"
	"threadr/models"

	"github.com/gorilla/sessions"
)

func LikeHandler(app *App) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodPost {
			http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
			return
		}

		session := r.Context().Value("session").(*sessions.Session)
		userID, ok := session.Values["user_id"].(int)
		if !ok {
			http.Error(w, "Unauthorized", http.StatusUnauthorized)
			return
		}

		postIDStr := r.FormValue("post_id")
		postID, err := strconv.Atoi(postIDStr)
		if err != nil {
			http.Error(w, "Invalid post ID", http.StatusBadRequest)
			return
		}

		likeType := r.FormValue("type")
		if likeType != "like" && likeType != "dislike" {
			http.Error(w, "Invalid like type", http.StatusBadRequest)
			return
		}

		existingLike, err := models.GetLikeByPostAndUser(app.DB, postID, userID)
		if err != nil {
			log.Printf("Error checking existing like: %v", err)
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			return
		}

		userAction := likeType // what the user's current vote will be after this
		if existingLike != nil {
			if existingLike.Type == likeType {
				// Toggle off
				err = models.DeleteLike(app.DB, postID, userID)
				userAction = "" // no active vote
				if err != nil {
					log.Printf("Error deleting like: %v", err)
					http.Error(w, "Internal Server Error", http.StatusInternalServerError)
					return
				}
			} else {
				err = models.UpdateLikeType(app.DB, postID, userID, likeType)
				if err != nil {
					log.Printf("Error updating like: %v", err)
					http.Error(w, "Internal Server Error", http.StatusInternalServerError)
					return
				}
			}
		} else {
			like := models.Like{
				PostID: postID,
				UserID: userID,
				Type:   likeType,
			}
			err = models.CreateLike(app.DB, like)
			if err != nil {
				log.Printf("Error creating like: %v", err)
				http.Error(w, "Internal Server Error", http.StatusInternalServerError)
				return
			}
		}

		// Fetch updated counts
		counts, err := models.GetLikeCountsByPostID(app.DB, postID)
		if err != nil {
			log.Printf("Error fetching like counts: %v", err)
			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
			return
		}

		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{
			"likes":      counts.Likes,
			"dislikes":   counts.Dislikes,
			"userAction": userAction,
		})
	}
}