// Helper for displaying edit changes so they can be manually verified

import {execSync} from 'node:child_process';

/**
 * Converts a string from UTF-8 to base64.
 * @param {string} str
 * @returns {string}
 */
const toBase64 = str => Buffer.from(str, 'utf-8').toString('base64');

/**
 * terrible terrible terrible string diff helper for debugging
 * @param {string} a
 * @param {string} b
 * @param {object} page Page object from the API, used to generate diff labels
 */
export function diff (a, b, page) {
	let labels = null;
	if (page) { // generate diff labels based on
		labels = [
			`${page.title}  (${page.revid ? `revision ${page.revid}` : 'current revision'}${page.timestamp ? ` from ${page.timestamp}` : ''})`,
			`${page.title}  (pending edit)`,
		];
	}
	// base64 input strings before passing to shell to avoid escaping issues
	// https://stackoverflow.com/a/60221847
	// use tail to cut off file info lines and re-add with fake filenames/dates
	// this function is so extra now holy shit
	execSync(String.raw`bash <<- 'EOF'
		diff --color=always -u \
			${labels ? `--label="$(echo '${toBase64(labels[0])}' | base64 -d)" ` : ''}<(echo '${toBase64(a)}' | base64 -d) \
			${labels ? `--label="$(echo '${toBase64(labels[1])}' | base64 -d)" ` : ''}<(echo '${toBase64(b)}' | base64 -d) \
		${labels ? `|| true` : `| tail -n +3` /* cut off header if no labels */}
	EOF`, {
		// display result directly in terminal
		stdio: 'inherit',
	});
}