package handlers

import (
	"5803024008/internal/db"
	"database/sql"
	"encoding/json"
	"net/http"
	"strconv"

	"github.com/gorilla/mux"
)

type GroupRequest struct {
	GroupName string `json:"group_name"`
}

type GroupResponse struct {
	GroupID   int    `json:"group_id"`
	GroupName string `json:"group_name"`
}

type ErrorResponse struct {
	Error string `json:"error"`
}

// Database connection - you'll need to inject this or use a global variable
var database *sql.DB

func SetDatabase(db *sql.DB) {
	database = db
}

func CreateGroupHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")

	var req GroupRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		w.WriteHeader(http.StatusBadRequest)
		json.NewEncoder(w).Encode(ErrorResponse{Error: "Invalid JSON format"})
		return
	}

	if req.GroupName == "" {
		w.WriteHeader(http.StatusBadRequest)
		json.NewEncoder(w).Encode(ErrorResponse{Error: "Group name is required"})
		return
	}

	if err := db.CreateGroup(database, req.GroupName); err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		json.NewEncoder(w).Encode(ErrorResponse{Error: "Failed to create group"})
		return
	}

	w.WriteHeader(http.StatusCreated)
	json.NewEncoder(w).Encode(map[string]string{"message": "Group created successfully"})
}

func DisplayTasksByGroupHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")

	vars := mux.Vars(r)
	groupIDStr := vars["groupId"]

	groupID, err := strconv.Atoi(groupIDStr)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		json.NewEncoder(w).Encode(ErrorResponse{Error: "Invalid group ID"})
		return
	}

	tasks, err := db.GetTasksByGroupID(database, groupID)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		json.NewEncoder(w).Encode(ErrorResponse{Error: "Failed to retrieve tasks"})
		return
	}

	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(tasks)
}

func RemoveGroupHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")

	vars := mux.Vars(r)
	groupIDStr := vars["groupId"]

	groupID, err := strconv.Atoi(groupIDStr)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		json.NewEncoder(w).Encode(ErrorResponse{Error: "Invalid group ID"})
		return
	}

	if err := db.RemoveGroup(database, groupID); err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		json.NewEncoder(w).Encode(ErrorResponse{Error: "Failed to remove group"})
		return
	}

	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(map[string]string{"message": "Group removed successfully"})
}

func GetGroupHandler(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json")

	vars := mux.Vars(r)
	groupIDStr := vars["groupId"]

	groupID, err := strconv.Atoi(groupIDStr)
	if err != nil {
		w.WriteHeader(http.StatusBadRequest)
		json.NewEncoder(w).Encode(ErrorResponse{Error: "Invalid group ID"})
		return
	}

	group, err := db.GetGroupByID(database, groupID)
	if err == sql.ErrNoRows {
		w.WriteHeader(http.StatusNotFound)
		json.NewEncoder(w).Encode(ErrorResponse{Error: "Group not found"})
		return
	}
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		json.NewEncoder(w).Encode(ErrorResponse{Error: "Failed to retrieve group"})
		return
	}

	response := GroupResponse{
		GroupID:   group.GroupId,
		GroupName: group.GroupName,
	}

	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(response)
}