class Sessions {
	constructor() {
		this._localStorage = window.localStorage
		this._sessionsButton = document.querySelector("#sessions-button")
		this._sessionList = document.querySelector("#sessions-dropdown")
		this._sessionLabel = document.querySelector("#sessions-button > .text")
		this._defaultSession = null
		this._sessionsObject = null
		this._init()
	}

  getDefaultSession() {
    return this._defaultSession.key
  }

	_setSessionDefault() {
		this._sessionLabel.innerText = this._defaultSession.name
	}

	_updateOnStartup() {
		var key = this._localStorage.getItem("defaultSession") || this._sessionsObject[0].key || lightdm.default_session

		var session = this._sessionsObject.find((val) => {return val.key === key})
		if (session === undefined) {
			// This should never happen
			this._defaultSession = {key: "awesome", name: "Awesome WM"}
		} else {
			this._defaultSession = session
		}
		this._setSessionDefault()
	}

	_updateDefaults(sessionObj) {
		if (!sessionObj) return
		this._defaultSession = sessionObj
		this._localStorage.setItem("defaultSession", this._defaultSession.key)
	}

	_setSessionList() {
		var dropdown = this._sessionList
		dropdown.innerHTML = ""
		for (let i = 0; i < this._sessionsObject.length; i++) {
			var name = this._sessionsObject[i].name
			var li = document.createElement("li")
			var button = document.createElement("button")
			button.innerText = name
			button.addEventListener("click", () => {
				this._updateDefaults(this._sessionsObject[i])
				this._setSessionDefault()
			})

			li.appendChild(button)
			dropdown.appendChild(li)
		}
	}

	_setKeydown() {
		var dropdown = this._sessionList
		dropdown.addEventListener("keydown", (ev) => {
			if (ev.keyCode == 27) {
				sessions_dropdown.classList.add("hide")
				this._sessionsButton.focus()
			}
		})
	}

	_setButton() {
		var dropdown = this._sessionList
		document.querySelector("#screen").addEventListener("click", (ev) => {
			if (ev.target == this._sessionsButton || ev.target.parentElement == this._sessionsButton) {
				dropdown.classList.toggle("hide")
			} else
			if (ev.target != this._sessionList && ev.target.closest(".dropdown") == null) {
				dropdown.classList.add("hide")
			}
		})
		document.querySelector("#screen").addEventListener("focusin", (ev) => {
			if (!dropdown.contains(document.activeElement) && document.activeElement != this._sessionsButton) {
				dropdown.classList.add("hide")
			}
		})
	}

	_init() {
		this._sessionsObject = lightdm.sessions
		this._updateOnStartup()
		this._setSessionList()
		this._setButton()
		this._setKeydown()
	}
}