import { readFile } from 'node:fs/promises';
import { resolve } from 'node:path';
import { convertAppleNote, parseExport } from './apple-notes.ts';
import type { ApiClient, NoteSummary } from './client.ts';
import { writeNote } from '../core/notes.ts';

/**
 * `schulcloud note` — the user's own lesson notes from the command line.
 *
 * The notes live on the server beside the index, so these go through /api like
 * everything else here. The exception is `import --out`, which writes files
 * directly: a migration of several hundred notes is worth doing offline, and
 * the result can be looked at before it goes anywhere.
 */

export interface NoteWriter {
	(line: string): void;
}

export async function noteList(
	api: ApiClient,
	filter: { subject?: string; since?: string; until?: string },
	long: boolean,
	out: NoteWriter,
): Promise<number> {
	const listing = await api.notes(filter);
	if (listing.count === 0) {
		out(`No notes yet. The server keeps them in ${listing.root}.`);
		return 0;
	}
	for (const note of listing.notes) out(formatLine(note, long));
	if (listing.notes.length < listing.count) {
		out(`… ${listing.count - listing.notes.length} more.`);
	}
	return 0;
}

export async function noteShow(api: ApiClient, path: string, out: NoteWriter): Promise<number> {
	const note = await api.note(path);
	out(`# ${note.title}`);
	const facts = [note.date, note.subject, note.tags.length > 0 ? note.tags.join(', ') : undefined].filter(Boolean);
	if (facts.length > 0) out(facts.join(' · '));
	out('');
	out(note.text ?? '');
	return 0;
}

export async function noteAdd(
	api: ApiClient,
	input: { title: string; text: string; subject?: string; date?: string; tags?: string[]; append?: boolean },
	out: NoteWriter,
): Promise<number> {
	const note = await api.addNote({ ...input, source: 'cli' });
	out(`${note.appended ? 'Appended to' : 'Saved'} ${note.path}`);
	return 0;
}

export interface ImportOptions {
	/** Write files here instead of sending them to the server. */
	outDir?: string;
	/** Force every note into one subject, rather than using its Notes folder. */
	subject?: string;
	dryRun?: boolean;
}

/**
 * Migrates an Apple Notes export.
 *
 * Notes with no text are skipped rather than imported empty: an export always
 * has some — locked notes, and notes that are one attachment — and a store
 * seeded with blank entries makes every later listing worse.
 */
export async function noteImport(
	api: ApiClient | undefined,
	file: string,
	options: ImportOptions,
	out: NoteWriter,
): Promise<number> {
	const contents = await readFile(resolve(file), 'utf8');
	const exported = parseExport(contents);
	if (exported.length === 0) {
		out(`${file} holds no notes. Re-run scripts/export-apple-notes.js on the Mac.`);
		return 1;
	}

	let imported = 0;
	let empty = 0;
	let failed = 0;
	const unreadable: string[] = [];

	for (const note of exported) {
		if (note.error) {
			unreadable.push(note.name || note.id);
			continue;
		}
		const converted = convertAppleNote(note, options.subject ? { subject: options.subject } : {});
		if (!converted.text.trim()) {
			empty++;
			continue;
		}
		if (options.dryRun) {
			out(`would import: ${converted.date ?? '????-??-??'} · ${converted.subject ?? '—'} · ${converted.title}`);
			imported++;
			continue;
		}
		try {
			if (options.outDir) {
				const { note: written } = await writeNote(options.outDir, converted);
				out(written.path);
			} else {
				if (!api) throw new Error('No server configured and no --out directory given.');
				const written = await api.addNote(converted);
				out(written.path);
			}
			imported++;
		} catch (error) {
			failed++;
			out(`FAILED ${converted.title}: ${error instanceof Error ? error.message : String(error)}`);
		}
	}

	out(
		`${options.dryRun ? 'Would import' : 'Imported'} ${imported} of ${exported.length} note(s)` +
			(empty > 0 ? `, skipped ${empty} with no text` : '') +
			(unreadable.length > 0 ? `, ${unreadable.length} unreadable in Notes` : '') +
			(failed > 0 ? `, FAILED ${failed}` : '') +
			'.',
	);
	if (unreadable.length > 0) {
		// Almost always locked notes: they are the ones worth naming, because the
		// fix is to unlock them in Notes and export again.
		out(`Unreadable (locked, or not downloaded from iCloud): ${unreadable.slice(0, 10).join('; ')}`);
	}
	return failed > 0 ? 1 : 0;
}

function formatLine(note: NoteSummary, long: boolean): string {
	const date = note.date ?? '          ';
	const subject = note.subject ? `[${note.subject}] ` : '';
	if (!long) return `${date}  ${subject}${note.title}`;
	const tags = note.tags.length > 0 ? `  #${note.tags.join(' #')}` : '';
	return `${date}  ${String(note.bytes).padStart(7)}  ${subject}${note.title}${tags}\n              ${note.path}`;
}