class Terminal {
	constructor() {
		this.terminalElem = document.getElementById("term")
		this.terminalContainerElem = document.getElementById("term-container")
		this.promptContainerElem = document.getElementById("prompt-container")
		this.promptsAndResponses = []
		this.commands = []
		this.commandPosition = this.commands.length
		this.currentPrompt = null
		this.active = false;
		this.initialized = false;
	}

	show() {
		if (!this.initialized) {
			this.initialized = true;
			this.initialize()
		} else {
			this.terminalElem.style.display = "block"
			this.terminalContainerElem.style.display = "block"
			if (this.currentPrompt) {
				this.currentPrompt.focus()
			}
		}
		terminalMode = true;
	}
	
	hide () {
		this.terminalElem.style.display = "none"
		this.terminalContainerElem.style.display = "none"
		terminalMode = false;
	}

	createPrompt() {
		this.commandPosition = this.commands.length

		var promptContainerElem = document.createElement("div")
		promptContainerElem.classList.add("prompt-container")

		var label = document.createElement("label")
		label.innerHTML = '>>>'

		var prompt = document.createElement("input")
		prompt.setAttribute("autofocus", true)

		var self = this
		prompt.addEventListener("keypress", function(event) {

			if (event.key === "Enter") {
				if (terminalMode && this.value !== ''){
					event.preventDefault();
					this.disabled = true;
					self.handlePrompt(this.value);
				}
			}
		})

		var clearFixDiv = document.createElement("div")
		clearFixDiv.classList.add("clearfix")

		promptContainerElem.appendChild(label);
		promptContainerElem.appendChild(prompt);
		this.terminalElem.appendChild(promptContainerElem);

		prompt.focus()
		this.currentPrompt = prompt
		this.promptsAndResponses.push(promptContainerElem)
	}

	initialize() {
		this.resize()
		this.show();
		this.createPrompt();
	}

	resize() {
		this.terminalElem.style.width = canvas.getBoundingClientRect().width - 40 + 'px';
		this.terminalElem.style.height = canvas.getBoundingClientRect().height - 80 + 'px';
		this.terminalElem.style.minHeight = canvas.getBoundingClientRect().width - 80 + 'px';
	}

	handlePrompt(promptText) {
		this.commands.push(promptText);
		this.determineResult(promptText);
		this.createPrompt();
	}

	determineResult(promptText) {
		var returnText
		if (promptText === 'help') {
			returnText = `Documented Commands:<br>
			========================================<br>
			help &nbsp&nbsp&nbsp&nbspShows the help screen<br>
			about &nbsp&nbsp&nbspProvides background of the terminal<br>
			clear &nbsp&nbsp&nbspClears the terminal<br>
			echo &nbsp&nbsp&nbsp&nbspDisplay a line of text<br>
			exit &nbsp&nbsp&nbsp&nbspExits the terminal<br>
			history &nbspPrints command history<br>
			<br>
			Terminal Functionality:<br>
			========================================<br>
			Up Arrow - cycle through commands<br>
			Down Arrow - cycle through commands<br>
			Ctrl+c - discard current prompt<br>
			Ctrl+d - exit<br>
			`

		} else if (promptText.split(" ")[0] == 'echo') {
			promptText = promptText.replaceAll('"', '')
			promptText = promptText.split(' ').slice(1)
			returnText = promptText.join(' ')
		} else if (promptText === 'history') {

		returnText = this.commands.join('<br>')

		} else if (promptText == 'exit') {
			this.hide()

		} else if (promptText == 'about') {
			returnText = 'I built this terminal emulator in JavaScript. While the functionality is quite simple, I wanted to showcase my love for linux and working in the terminal. All actions that can be done in the main world like: looking at my portfolio, downloading my resume, or playing one of the games I made can be done through this terminal. <br><br> I also added some quality of life commands like clear, exit, echo and more for the fun of it. That\'s  right! This is what I do for fun :)'

		} else if (promptText == 'clear') {
			this.clear()

		} else if (['vim', 'nvim', 'nano', 'ed'].includes(promptText)) {
			returnText = 'Did you really think I coded a text editor in here!?'

		} else {
			returnText = 'Unkown command, please type "help" for options'

		}

		if (returnText) {
			var responseElem = document.createElement('span')
			responseElem.innerHTML = returnText
			this.terminalElem.appendChild(responseElem)
			this.promptsAndResponses.push(responseElem)
		}
	}

	clear() {
		for (let i = 0; i < this.promptsAndResponses.length; i++) {
			this.promptsAndResponses[i].style.display = "none";
		}
	}

	getKeystroke() {
		var self = this
		_listener = function (event) {
			console.log(event.code)
			if (
				["ArrowUp", "ArrowDown", "ControlLeft"].indexOf(event.code,) > -1
			) {
				event.preventDefault();
			}

			if (event.ctrlKey && event.key === 'd') {
				event.preventDefault();
			}
			
			if (event.key === "ArrowUp") {
				if (self.commands.length > 0) {
					var nextCommandPosition = self.commandPosition - 1

					if (nextCommandPosition < 0) {
						nextCommandPosition = self.commands.length - 1
					}

					self.currentPrompt.value = self.commands[nextCommandPosition]
					self.commandPosition = nextCommandPosition;
				}
			}

			if (event.key === "ArrowDown") {
				if (self.commands.length > 0) {
					var nextCommandPosition = self.commandPosition + 1

					if (nextCommandPosition > self.commands.length - 1) {
						nextCommandPosition = 0
					}

					self.currentPrompt.value = self.commands[nextCommandPosition]
					self.commandPosition = nextCommandPosition;
				}
			}

			if (event.ctrlKey && event.key === 'c') {
				self.createPrompt()
			}

			if (event.ctrlKey && event.key === 'd') {
				self.hide()
			}
		}
		document.addEventListener("keydown", _listener);
	}
}