#!/usr/bin/env osascript -l JavaScript
/**
 * Exports Apple Notes to one JSON object per line, on stdout.
 *
 * Run this **on the Mac that has the notes**:
 *
 *   osascript -l JavaScript scripts/export-apple-notes.js > notes.ndjson
 *   osascript -l JavaScript scripts/export-apple-notes.js --folder Deutsch > deutsch.ndjson
 *
 * then hand the file to `schulcloud note import notes.ndjson`.
 *
 * Why this exists at all: Notes.app has no export. Its database is a Core Data
 * store whose bodies are compressed protobuf, and the iCloud copy is encrypted,
 * so scripting the app is not the clumsy route to the notes — it is the only
 * one. The first run raises a macOS permission dialog ("Terminal wants access
 * to Notes"); without it every note comes back empty.
 *
 * JXA and not AppleScript because it can serialise JSON, and because reading
 * properties one note at a time is what keeps a locked note from aborting the
 * run rather than a language preference.
 */

ObjC.import('stdlib');

function run(argv) {
	const options = parseArguments(argv);
	const notes = Application('Notes');
	notes.includeStandardAdditions = true;

	let items;
	try {
		items = notes.notes();
	} catch (error) {
		return fail(
			'Could not read Notes. Grant the terminal access under System Settings → Privacy & Security → ' +
				'Automation, then run this again.\n' + error,
		);
	}

	let written = 0;
	let skipped = 0;
	for (let i = 0; i < items.length; i++) {
		const note = items[i];
		const record = readNote(note);
		if (!record) {
			skipped++;
			continue;
		}
		if (options.folder && (record.folder || '').toLowerCase().indexOf(options.folder.toLowerCase()) === -1) continue;
		// One object per line, so a huge export streams and a bad note costs one line.
		console.log(JSON.stringify(record));
		written++;
	}

	// stderr, so it never lands in the file being redirected.
	log('Exported ' + written + ' note(s)' + (skipped > 0 ? ', skipped ' + skipped + ' unreadable' : '') + '.');
	return '';
}

function readNote(note) {
	try {
		// Read the body first: it is the property a locked note refuses, and
		// there is no point building a record we cannot fill.
		const body = note.body();
		return {
			id: safe(function () { return note.id(); }, ''),
			name: safe(function () { return note.name(); }, ''),
			body: body || '',
			folder: safe(function () { return folderPath(note.container()); }, ''),
			created: safe(function () { return iso(note.creationDate()); }, ''),
			modified: safe(function () { return iso(note.modificationDate()); }, ''),
		};
	} catch (error) {
		// A locked note, or one iCloud has not downloaded. Reported, not dropped
		// silently: a missing lesson is worse than a line in the file.
		return {
			id: safe(function () { return note.id(); }, ''),
			name: safe(function () { return note.name(); }, '(unreadable)'),
			body: '',
			error: String(error),
		};
	}
}

/** "Schule/Deutsch" — the import takes the last segment as the subject. */
function folderPath(container) {
	const parts = [];
	let current = container;
	for (let depth = 0; current && depth < 8; depth++) {
		const name = safe(function () { return current.name(); }, '');
		if (!name) break;
		parts.unshift(name);
		current = safe(function () { return current.container(); }, null);
	}
	return parts.join('/');
}

/**
 * A Date as local ISO, not UTC.
 *
 * `toISOString` would shift a note taken at 08:30 in Erfurt back to the
 * previous day for anything written before 01:00 or 02:00, and the date is
 * the whole point of the record.
 */
function iso(date) {
	if (!date) return '';
	const pad = function (value) { return String(value).padStart(2, '0'); };
	return (
		date.getFullYear() + '-' + pad(date.getMonth() + 1) + '-' + pad(date.getDate()) +
		'T' + pad(date.getHours()) + ':' + pad(date.getMinutes()) + ':' + pad(date.getSeconds())
	);
}

function safe(read, fallback) {
	try {
		const value = read();
		return value === undefined || value === null ? fallback : value;
	} catch (error) {
		return fallback;
	}
}

function parseArguments(argv) {
	const options = { folder: '' };
	for (let i = 0; i < argv.length; i++) {
		if (argv[i] === '--folder' && argv[i + 1]) options.folder = argv[++i];
	}
	return options;
}

function log(message) {
	$.NSFileHandle.fileHandleWithStandardError.writeData(
		$.NSString.alloc.initWithUTF8String(message + '\n').dataUsingEncoding($.NSUTF8StringEncoding),
	);
}

function fail(message) {
	log(message);
	$.exit(1);
}