class CalendarViewController extends TimeCardsViewController {
	viewDidLoad() {
		TimeCards.dataManager.addDataListener("user", {
			deleted: 0
		}, this.onUserUpdate.bind(this));

		//Initiate the date update interval which will check if the time goes past 23:59:59 and select the next day automatically.
		setInterval(this.dateUpdate.bind(this), 60000);
	}

	onUserUpdate(userId, user, sortedBefore) {
		//Initialise the user dropdown if it has not been done before.
		if (!this.userDropdown) {
			this.userDropdown = new ContextMenu();
			this.userDropdown.element.id = "work-time-user-dropdown";
			this.userDropdown.setViewController(this);
			this.userDropdownEntries = { };
		}

		//Get the user dropdown entry for the changed user.
		var userEntry = (userId in this.userDropdownEntries) ? this.userDropdownEntries[userId] : null;

		//We insert the session user's entry at the very top. All the other users are sorted alphabetically.
		var insertBeforeElement = user.is_session_user ? this.userDropdown.element.firstChild.firstChild : ((sortedBefore in this.userDropdownEntries) ? this.userDropdownEntries[sortedBefore] : null);

		if (!userEntry) {
			//Handle the added user.
			var userEntry = document.createElement("menu-option");
			userEntry.innerText = user.full_name;
			if (user.is_session_user) {
				userEntry.innerText += " (me)";
			}
			userEntry.setAttribute("value", userId);
			userEntry.setAttribute("action", "onUserSelected");

			if (user.is_session_user) {
				this.selectUser(user);
				this.selectDay(Time.getCurrentLocalDayIndex());
			}

			this.userDropdown.element.firstChild.insertBefore(userEntry, insertBeforeElement);
			this.userDropdownEntries[user.user_id] = userEntry;
		}
		else if (!user) {
			//Handle the deleted user.
			delete this.userDropdownEntries[user.user_id];
			this.userDropdown.element.firstChild.removeChild(userEntry);
		}
		else {
			//Handle the changed user.
			userEntry.innerText = user.full_name;
			if (user.is_session_user) {
				userEntry.innerText += " (me)";
			}

			//Update the position in case the name has changed.
			this.userDropdown.element.firstChild.insertBefore(userEntry, insertBeforeElement);

			//Also re-select the user to update the name in the navigation bar.
			if (userId == this.selectedUser) {
				this.selectUser(user);
			}
		}
	}

	onUserDropdownPressed(event) {
		//event.stopPropagation();

		this.userDropdown.showForElement(event.currentTarget, "bottom");
	}

	onUserSelected(event) {
		this.selectUser(TimeCards.dataManager.getEntity("user", event.currentTarget.getAttribute("value")));
		this.dayViewController.displayDay(this.selectedDayIndex, this.selectedUser);
	}

	selectUser(user) {
		this.selectedUser = user.user_id;

		this.displayingWorkTimeUserNameLabel.innerText = user.full_name;
	}

	/**
	 * Selects the given day in the date selection and displays the work time periods for that date.
	 */
	selectDay(dayIndex) {
		this.selectedDayIndex = dayIndex;
		var date = Time.getDateForLocalDayIndex(this.selectedDayIndex);

		//Enable or disable the today button.
		//We store a flag that indicates whether the selected date is "today" or not. Used in the dateUpdate() function below.
		this.isToday = this.selectedDayIndex == Time.getCurrentLocalDayIndex();
		if (this.isToday) {
			if (!this.todayButton.hasAttribute("disabled")) {
				this.todayButton.setAttribute("disabled", "");
			}
		}
		else {
			this.todayButton.removeAttribute("disabled");
		}

		var weekdayString = date.toLocaleDateString(undefined, {
			weekday: "long"
		});

		this.dayNameLabel.innerText = weekdayString;
		this.dateField.value = Time.getUnixDate(date);

		this.dayViewController.displayDay(this.selectedDayIndex, this.selectedUser);
	}

	/**
	 * Move the day selection by the given amount of days (positive or negative amount).
	 */
	selectDayRelative(days) {
		this.selectDay(this.selectedDayIndex + days);
	}

	onNextDayButtonPressed(event) {
		this.selectDayRelative(1);
	}

	onPreviousDayButtonPressed(event) {
		this.selectDayRelative(-1);
	}

	onSelectTodayButtonPressed(event) {
		this.selectDay(Time.getCurrentLocalDayIndex());
	}

	/**
	 * Called every minute and checks whether a new day has started (i.e. the current date is not the same as the one from the last update).
	 * This way, the date view will select the next day if the time passes 23:59:59.
	 */
	dateUpdate() {
		//Do nothing if not the current day is selected at all.
		if (!this.isToday) {
			return;
		}

		var currentDayIndex = Time.getCurrentLocalDayIndex();

		//Only perform the check if this is not the first call.
		if (this.lastUpdateDayIndex) {
			//Select the new current day index if it is different from the last update.
			if (this.lastUpdateDayIndex != currentDayIndex) {
				this.selectDay(currentDayIndex);
			}
		}

		this.lastUpdateDayIndex = currentDayIndex;
	}

	/**
	 * Called when the user changes the date in the date field.
	 */
	onDateFieldChanged(event) {
		if (!this.dateField.value || this.dateField.value == "") {
			this.dayNameLabel.innerText = "Invalid date";
			this.dayView.style.display = "none";
			return;
		}

		this.dayView.style.display = "";

		this.selectDay(Time.getLocalDayIndex(new Date(this.dateField.value)));
	}
}

UIKit.registerViewControllerType(CalendarViewController);