package endpoints

import (
	"arbeitszeitmessung/helper"
	"arbeitszeitmessung/models"
	"arbeitszeitmessung/templates"
	"context"
	"encoding/json"
	"log"
	"net/http"
	"sort"
	"strconv"
	"time"
)

// Frontend relevant backend functionality -> not used by the arduino devices
func TimeHandler(w http.ResponseWriter, r *http.Request) {
	helper.RequiresLogin(Session, w, r)
	helper.SetCors(w)
	switch r.Method {
	case http.MethodGet:
		getBookings(w, r)
		break
	case http.MethodPost:
		updateBooking(w, r)
		break
	case http.MethodOptions:
		// just support options header for non GET Requests from SWAGGER
		w.WriteHeader(http.StatusOK)
		break
	default:
		http.Error(w, "Method not allowed!", http.StatusMethodNotAllowed)
		break
	}
}

func parseTimestamp(r *http.Request, getKey string, fallback string) (time.Time, error) {
	getTimestamp := r.URL.Query().Get(getKey)
	if getTimestamp == "" {
		getTimestamp = fallback
	}
	Timestamp, err := time.Parse("2006-01-02", getTimestamp)
	if err != nil {
		return time.Now(), err
	}
	return Timestamp, nil
}

// Returns bookings from DB with similar card uid -> checks for card uid in http query params
func getBookings(w http.ResponseWriter, r *http.Request) {
	user, err := (*models.User).GetUserFromSession(nil, Session, r.Context())
	if err != nil {
		log.Println("No user found with the given personal number!")
		http.Redirect(w, r, "/user/login", http.StatusSeeOther)
		return
	}

	// TODO add config for timeoffset
	tsFrom, err := parseTimestamp(r, "time_from", time.Now().AddDate(0, -1, 0).Format("2006-01-02"))
	if err != nil {
		log.Println("Error parsing 'from' time", err)
		http.Error(w, "Timestamp 'from' cannot be parsed!", http.StatusBadRequest)
		return
	}
	tsTo, err := parseTimestamp(r, "time_to", time.Now().Format("2006-01-02"))
	if err != nil {
		log.Println("Error parsing 'to' time", err)
		http.Error(w, "Timestamp 'to' cannot be parsed!", http.StatusBadRequest)
		return
	}
	tsTo = tsTo.AddDate(0, 0, 1) // so that today is inside

	workDays := (*models.WorkDay).GetWorkDays(nil, user.CardUID, tsFrom, tsTo)
	sort.Slice(workDays, func(i, j int) bool {
		return workDays[i].Day.After(workDays[j].Day)
	})

	if r.Header.Get("Accept") == "application/json" {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusOK)
		json.NewEncoder(w).Encode(workDays)
		return
	}

	ctx := context.WithValue(r.Context(), "user", user)
	templates.TimePage(workDays).Render(ctx, w)
}

func updateBooking(w http.ResponseWriter, r *http.Request) {
	r.ParseForm()
	var loc *time.Location
	loc, err := time.LoadLocation(helper.GetEnv("TZ", "Europe/Berlin"))
	if err != nil {
		log.Println("Error loading location", err)
		loc = time.Local
	}
	user, err := (*models.User).GetUserFromSession(nil, Session, r.Context())
	if err != nil {
		log.Println("No user found!", err)
		return
	}
	switch r.FormValue("action") {
	case "add":
		timestamp, err := time.ParseInLocation("2006-01-02|15:04", r.FormValue("date")+"|"+r.FormValue("timestamp"), loc)
		if err != nil {
			log.Println("Error parsing timestamp", err)
			return
		}

		var check_in_out int
		check_in_out, err = strconv.Atoi(r.FormValue("check_in_out"))
		if err != nil {
			log.Println("Error parsing check_in_out", err)
			return
		}

		newBooking := (*models.Booking).New(nil, user.CardUID, 0, int16(check_in_out))
		newBooking.Timestamp = timestamp
		err = newBooking.InsertWithTimestamp()
		if err != nil {
			log.Println("Error inserting booking", err)
		}
		break
	case "change":
		absenceType, err := strconv.Atoi(r.FormValue("absence"))
		if err != nil {
			log.Println("Error parsing absence type.", err)
			absenceType = 0
		}
		if absenceType != 0 {
			createAbsence(absenceType, user, loc, r)
		}
		for index, possibleBooking := range r.PostForm {
			if len(index) > 7 && index[:7] == "booking" {
				booking_id, err := strconv.Atoi(index[8:])
				if err != nil {
					log.Println("Error parsing bookingId", err)
					continue
				}
				booking, err := (*models.Booking).GetBookingById(nil, booking_id)
				if err != nil {
					log.Println("Error getting booking!", err)
					continue
				}
				parsedTime, err := time.ParseInLocation("15:04", possibleBooking[0], booking.Timestamp.Location())
				if err != nil {
					log.Println("Error parsing time!", err)
					continue
				}
				// log.Println("Parsing time", parsedTime)
				booking.UpdateTime(parsedTime)
			}
		}
		break
	}

	getBookings(w, r)
}

func createAbsence(absenceType int, user models.User, loc *time.Location, r *http.Request) {
	absenceDate, err := time.ParseInLocation("2006-01-02", r.FormValue("date"), loc)
	if err != nil {
		log.Println("Cannot get date from input! Skipping absence creation", err)
		return
	}
	absence := models.NewAbsence(user.CardUID, int8(absenceType), absenceDate)
	err = absence.Insert()
	if err != nil {
		log.Println("Error inserting absence!", err)
		return
	}
}

func getBookingsAPI(w http.ResponseWriter, r *http.Request) {
	_user_pn := r.URL.Query().Get("personal_nummer")
	user_pn, err := strconv.Atoi(_user_pn)
	if err != nil {
		log.Println("No personal numver found!")
		http.Error(w, "No personal number found", http.StatusBadRequest)
		return
	}

	user, err := (*models.User).GetByPersonalNummer(nil, user_pn)
	if err != nil {
		log.Println("No user found with the given personal number!")
		http.Error(w, "No user found", http.StatusNotFound)
		return
	}

	// TODO add config for timeoffset
	tsFrom, err := parseTimestamp(r, "time_from", time.Now().AddDate(0, -1, 0).Format("2006-01-02"))
	if err != nil {
		log.Println("Error parsing 'from' time", err)
		http.Error(w, "Timestamp 'from' cannot be parsed!", http.StatusBadRequest)
		return
	}
	tsTo, err := parseTimestamp(r, "time_to", time.Now().Format("2006-01-02"))
	if err != nil {
		log.Println("Error parsing 'to' time", err)
		http.Error(w, "Timestamp 'to' cannot be parsed!", http.StatusBadRequest)
		return
	}
	tsTo = tsTo.AddDate(0, 0, 1) // so that today is inside

	bookings, err := (*models.Booking).GetBookingsGrouped(nil, user.CardUID, tsFrom, tsTo)
	if err != nil {
		log.Println("Error getting bookings: ", err)
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(bookings)
}

// Updates a booking form the given json body
func updateBookingAPI(w http.ResponseWriter, r *http.Request) {
	_booking_id := r.URL.Query().Get("counter_id")
	if _booking_id == "" {
		http.Error(w, "Missing bookingID query parameter", http.StatusBadRequest)
		return
	}
	booking_id, err := strconv.Atoi(_booking_id)
	if err != nil {
		http.Error(w, "Invalid bookingID query parameter", http.StatusBadRequest)
		return
	}
	bookingDB, err := (*models.Booking).GetBookingById(nil, booking_id)
	if err != nil {
		log.Println("Error getting booking: ", err)
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}
	var booking models.Booking
	dec := json.NewDecoder(r.Body)
	dec.DisallowUnknownFields()
	err = dec.Decode(&booking)
	if err != nil {
		log.Println("Error parsing booking: ", err)
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}
	if booking.CounterId != 0 && booking.CounterId != bookingDB.CounterId {
		log.Println("Booking Ids do not match")
		http.Error(w, "Booking Ids do not match", http.StatusBadRequest)
		return
	}
	bookingDB.Update(booking)
	bookingDB.Save()
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(bookingDB)
}