import process from 'node:process';
import {stripVTControlCharacters} from 'node:util';
import yoctocolors from 'yoctocolors';

const isUnicodeSupported = process.platform !== 'win32'
	|| Boolean(process.env.WT_SESSION) // Windows Terminal
	|| process.env.TERM_PROGRAM === 'vscode';

const isInteractive = stream => Boolean(
	stream.isTTY
	&& process.env.TERM !== 'dumb'
	&& !('CI' in process.env),
);

const infoSymbol = yoctocolors.blue(isUnicodeSupported ? 'ℹ' : 'i');
const successSymbol = yoctocolors.green(isUnicodeSupported ? '✔' : '√');
const warningSymbol = yoctocolors.yellow(isUnicodeSupported ? '⚠' : '‼');
const errorSymbol = yoctocolors.red(isUnicodeSupported ? '✖' : '×');

const defaultSpinner = {
	frames: isUnicodeSupported
		? [
			'⠋',
			'⠙',
			'⠹',
			'⠸',
			'⠼',
			'⠴',
			'⠦',
			'⠧',
			'⠇',
			'⠏',
		]
		: [
			'-',
			'\\',
			'|',
			'/',
		],
	interval: 80,
};

class YoctoSpinner {
	#frames;
	#interval;
	#currentFrame = -1;
	#timer;
	#text;
	#stream;
	#color;
	#lines = 0;
	#exitHandlerBound;
	#isInteractive;
	#lastSpinnerFrameTime = 0;

	constructor(options = {}) {
		const spinner = options.spinner ?? defaultSpinner;
		this.#frames = spinner.frames;
		this.#interval = spinner.interval;
		this.#text = options.text ?? '';
		this.#stream = options.stream ?? process.stderr;
		this.#color = options.color ?? 'cyan';
		this.#isInteractive = isInteractive(this.#stream);
		this.#exitHandlerBound = this.#exitHandler.bind(this);
	}

	start(text) {
		if (text) {
			this.#text = text;
		}

		if (this.isSpinning) {
			return this;
		}

		this.#hideCursor();
		this.#render();
		this.#subscribeToProcessEvents();

		this.#timer = setInterval(() => {
			this.#render();
		}, this.#interval);

		return this;
	}

	stop(finalText) {
		if (!this.isSpinning) {
			return this;
		}

		clearInterval(this.#timer);
		this.#timer = undefined;
		this.#showCursor();
		this.clear();
		this.#unsubscribeFromProcessEvents();

		if (finalText) {
			this.#stream.write(`${finalText}\n`);
		}

		return this;
	}

	#symbolStop(symbol, text) {
		return this.stop(`${symbol} ${text ?? this.#text}`);
	}

	success(text) {
		return this.#symbolStop(successSymbol, text);
	}

	error(text) {
		return this.#symbolStop(errorSymbol, text);
	}

	warning(text) {
		return this.#symbolStop(warningSymbol, text);
	}

	info(text) {
		return this.#symbolStop(infoSymbol, text);
	}

	get isSpinning() {
		return this.#timer !== undefined;
	}

	get text() {
		return this.#text;
	}

	set text(value) {
		this.#text = value ?? '';
		this.#render();
	}

	get color() {
		return this.#color;
	}

	set color(value) {
		this.#color = value;
		this.#render();
	}

	clear() {
		if (!this.#isInteractive) {
			return this;
		}

		this.#stream.cursorTo(0);

		for (let index = 0; index < this.#lines; index++) {
			if (index > 0) {
				this.#stream.moveCursor(0, -1);
			}

			this.#stream.clearLine(1);
		}

		this.#lines = 0;

		return this;
	}

	#render() {
		// Ensure we only update the spinner frame at the wanted interval,
		// even if the frame method is called more often.
		const now = Date.now();
		if (this.#currentFrame === -1 || now - this.#lastSpinnerFrameTime >= this.#interval) {
			this.#currentFrame = ++this.#currentFrame % this.#frames.length;
			this.#lastSpinnerFrameTime = now;
		}

		const applyColor = yoctocolors[this.#color] ?? yoctocolors.cyan;
		const frame = this.#frames[this.#currentFrame];
		let string = `${applyColor(frame)} ${this.#text}`;

		if (!this.#isInteractive) {
			string += '\n';
		}

		this.clear();
		this.#write(string);

		if (this.#isInteractive) {
			this.#lines = this.#lineCount(string);
		}
	}

	#write(text) {
		this.#stream.write(text);
	}

	#lineCount(text) {
		const width = this.#stream.columns ?? 80;
		const lines = stripVTControlCharacters(text).split('\n');

		let lineCount = 0;
		for (const line of lines) {
			lineCount += Math.max(1, Math.ceil(line.length / width));
		}

		return lineCount;
	}

	#hideCursor() {
		if (this.#isInteractive) {
			this.#write('\u001B[?25l');
		}
	}

	#showCursor() {
		if (this.#isInteractive) {
			this.#write('\u001B[?25h');
		}
	}

	#subscribeToProcessEvents() {
		process.once('SIGINT', this.#exitHandlerBound);
		process.once('SIGTERM', this.#exitHandlerBound);
	}

	#unsubscribeFromProcessEvents() {
		process.off('SIGINT', this.#exitHandlerBound);
		process.off('SIGTERM', this.#exitHandlerBound);
	}

	#exitHandler(signal) {
		if (this.isSpinning) {
			this.stop();
		}

		// SIGINT: 128 + 2
		// SIGTERM: 128 + 15
		const exitCode = signal === 'SIGINT' ? 130 : (signal === 'SIGTERM' ? 143 : 1);
		process.exit(exitCode);
	}
}

export default function yoctoSpinner(options) {
	return new YoctoSpinner(options);
}