#!/usr/bin/env node

/* VIBE ALERT

This code was generated using OpenAI’s ChatGPT (GPT-5.2 Thinking, large language model).
The output has not been independently reviewed, audited, or comprehensively validated,
and has only been superficially tested. It should be considered experimental and not fully vetted for production use.

*/

import fs from 'node:fs';
import readline from 'node:readline';

const ansiRegex = /\x1b\[(?:[0-9]{1,3}(?:;[0-9]{1,3})*)?[mK]?/g;

function tokenize(line) {
	const tokens = [];
	let lastIndex = 0;

	for (const match of line.matchAll(ansiRegex)) {
		const index = match.index;

		if (index > lastIndex) {
			tokens.push({ type: 'text', value: line.slice(lastIndex, index) });
		}

		tokens.push({ type: 'ansi', value: match[0] });
		lastIndex = index + match[0].length;
	}

	if (lastIndex < line.length) {
		tokens.push({ type: 'text', value: line.slice(lastIndex) });
	}

	return tokens;
}

function truncateLine(line, maxLength, tabSize=4) {
	let col = 0;
	let result = '';

	const tokens = tokenize(line);

	for (const token of tokens) {
		if (col >= maxLength) {
			break;
		}

		if (token.type === 'ansi') {
			result += token.value;
		} else {
			let i = 0;

			while (i < token.value.length && col < maxLength) {
				const ch = token.value[i];

				if (ch === '\t') {
					const w = tabSize - (col % tabSize);

					if (col + w > maxLength) {
						i = token.value.length;
					} else {
						result += ' '.repeat(w);
						col += w;
						i++;
					}
				} else {
					result += ch;
					col += 1;
					i++;
				}
			}
		}
	}

	return result.replace(/\s+$/, '') + '\x1b[0m';
}
function parseArgs(argv) {
	let filename = '/dev/stdin';
	let length = 50;

	for (let i = 2; i < argv.length; i++) {
		const arg = argv[i];

		if (arg === '-l' || arg === '--length') {
			const value = argv[i + 1];
			if (value) {
				length = parseInt(value, 10);
				i++;
			}
		} else {
			filename = arg;
		}
	}

	return { filename, length };
}

async function main() {
	const { filename, length } = parseArgs(process.argv);

	let inputStream;

	if (filename === '/dev/stdin') {
		inputStream = process.stdin;
	} else {
		inputStream = fs.createReadStream(filename, { encoding: 'utf8' });
	}

	const rl = readline.createInterface({
		input: inputStream,
		crlfDelay: Infinity,
	});

	for await (const line of rl) {
		const truncated = truncateLine(line, length);
		process.stdout.write(truncated + '\n');
	}
}

await main();