// *************************************************************************
// * (C)opyright 2026         by Ruben Carlo Benante                       *
// *                                                                       *
// * This program is free software; you can redistribute it and/or modify  *
// *  it under the terms of the GNU General Public License as published by *
// *  the Free Software Foundation, either version 3 of the License, or    *
// *  (at your option) any later version.                                  *
// *                                                                       *
// * This program is distributed in the hope that it will be useful,       *
// *  but WITHOUT ANY WARRANTY; without even the implied warranty of       *
// *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
// *  GNU General Public License for more details.                         *
// *                                                                       *
// * You should have received a copy of the GNU General Public License     *
// *  along with this program.  If not, see http://www.gnu.org/licenses/.  *
// *                                                                       *
// * Contact author at:                                                    *
// *  Ruben Carlo Benante                                                  *
// *  rcb@beco.cc                                                          *
// *************************************************************************

import {
	Plugin,
	TFile,
	TAbstractFile,
	TFolder,
	Menu,
	Notice,
	moment,
} from 'obsidian';
import {
	extractPrefix,
	computeBasename,
	generateSlug,
	buildFilename,
} from './slug';
import {
	ZettelcleanSettings,
	DEFAULT_SETTINGS,
	ZettelcleanSettingTab,
} from './settings';

const SETTLE_MS = 4000; // rename ~4s after the H1 stops changing
const COOLDOWN_MS = 6000; // do not rename the same path again within 6s

export default class ZettelcleanPlugin extends Plugin {
	settings!: ZettelcleanSettings;
	private renameTimers = new Map<string, number>();
	private lastRenamedAt = new Map<string, number>();
	private isRenameInProgress = false;

	async onload() {
		await this.loadSettings();
		this.addSettingTab(new ZettelcleanSettingTab(this.app, this));

		// Fires after the metadata cache reparses a note, so headings[] is fresh.
		this.registerEvent(
			this.app.metadataCache.on('changed', (file) =>
				this.scheduleSync(file),
			),
		);
		// File-explorer right-click menu: retrofit item for files, slug item for folders.
		this.registerEvent(
			this.app.workspace.on('file-menu', (menu, file) => {
				this.addTimeIdMenu(menu, file);
				this.addFolderSlugMenu(menu, file);
			}),
		);
	}

	onunload() {
		for (const t of this.renameTimers.values()) window.clearTimeout(t);
		this.renameTimers.clear();
	}

	async loadSettings() {
		this.settings = Object.assign(
			{},
			DEFAULT_SETTINGS,
			(await this.loadData()) as Partial<ZettelcleanSettings>,
		);
	}

	async saveSettings() {
		await this.saveData(this.settings);
	}

	private pathFor(file: TFile, base: string): string {
		const dir =
			file.parent && file.parent.path !== '/' ? `${file.parent.path}/` : '';
		return `${dir}${base}.md`;
	}

	// Guard layer: only the actively edited zettel, honoring the 6s cooldown,
	// (re)arming the 4s settle timer on every cache change.
	private scheduleSync(file: TAbstractFile) {
		if (this.isRenameInProgress) return; // our own rename, ignore
		if (!(file instanceof TFile) || file.extension !== 'md') return;
		const allowDate = this.settings.prefixMode === 'date';
		if (extractPrefix(file.basename, allowDate) === null) return; // opt-in gate
		if (this.app.workspace.getActiveFile() !== file) return; // only the edited note

		const last = this.lastRenamedAt.get(file.path);
		if (last && Date.now() - last < COOLDOWN_MS) return; // 6s cooldown

		const existing = this.renameTimers.get(file.path);
		if (existing) window.clearTimeout(existing);
		this.renameTimers.set(
			file.path,
			window.setTimeout(() => {
				this.renameTimers.delete(file.path);
				void this.syncNow(file);
			}, SETTLE_MS),
		);
	}

	// Compute the target basename via the sticky rule, bail if unchanged, else rename.
	private async syncNow(file: TFile) {
		const first = this.app.metadataCache.getFileCache(file)?.headings?.[0];
		const h1 = first && first.level === 1 ? first.heading : '';
		const allowDate = this.settings.prefixMode === 'date';

		const newBase = computeBasename(file.basename, h1, allowDate);
		if (newBase === null || newBase === file.basename) return; // unrecognized or no change

		const newPath = this.pathFor(file, newBase);
		if (this.app.vault.getAbstractFileByPath(newPath)) {
			new Notice(`Can't rename to "${newBase}.md" - that name already exists`);
			return; // conflict: keep current name, tell the user
		}
		this.isRenameInProgress = true;
		try {
			await this.app.fileManager.renameFile(file, newPath);
			this.lastRenamedAt.set(newPath, Date.now());
		} catch (e) {
			console.error('zettelclean: rename failed', e);
			new Notice('Rename failed (see console)');
		} finally {
			this.isRenameInProgress = false;
		}
	}

	private addTimeIdMenu(menu: Menu, file: TAbstractFile) {
		if (!(file instanceof TFile) || file.extension !== 'md') return;
		const allowDate = this.settings.prefixMode === 'date';
		if (extractPrefix(file.basename, allowDate) !== null) return; // already a zettel
		menu.addItem((item) =>
			item
				.setTitle('Prefix timestamp to filename')
				.setIcon('clock')
				.onClick(() => void this.addTimeId(file)),
		);
	}

	// Retrofit: mint a fresh timestamp for a note that has no TIMEID yet.
	private async addTimeId(file: TFile) {
		let id = moment().format('YYYYMMDDHHmmss'); // core Unique-note format
		const first = this.app.metadataCache.getFileCache(file)?.headings?.[0];
		const h1 =
			first && first.level === 1 ? first.heading : file.basename;
		const slug = generateSlug(h1);

		let target = this.pathFor(file, buildFilename(id, slug));
		// Rare same-second + same-title collision: extend the id (up to 18 digits).
		while (this.app.vault.getAbstractFileByPath(target) && id.length < 18) {
			id += String(Math.floor(Date.now() % 10));
			target = this.pathFor(file, buildFilename(id, slug));
		}
		await this.app.fileManager.renameFile(file, target);
	}

	// Folder right-click: slug the folder's own name (this folder only, instant).
	private addFolderSlugMenu(menu: Menu, file: TAbstractFile) {
		if (!(file instanceof TFolder) || file.isRoot()) return; // never the vault root
		menu.addItem((item) =>
			item
				.setTitle('Slug folder name')
				.setIcon('folder')
				.onClick(() => void this.slugFolder(file)),
		);
	}

	private async slugFolder(folder: TFolder) {
		const newName = generateSlug(folder.name);
		if (!newName || newName === folder.name) {
			new Notice('Folder name is already clean');
			return;
		}
		const parent = folder.parent;
		const dir = parent && parent.path !== '/' ? `${parent.path}/` : '';
		const newPath = `${dir}${newName}`; // folders have no extension
		if (this.app.vault.getAbstractFileByPath(newPath)) {
			new Notice(`Cannot rename: "${newName}" already exists`);
			return;
		}
		await this.app.fileManager.renameFile(folder, newPath); // updates [[links]]
		new Notice(`Renamed folder "${folder.name}" -> "${newName}"`);
	}
}