import { FolderEntity } from '../services/database/types';
import BaseModel from '../BaseModel';
import time from '../time';
import { _ } from '../locale';

import Note from './Note';
import Database from '../database';
import BaseItem from './BaseItem';
const { substrWithEllipsis } = require('../string-utils.js');

interface FolderEntityWithChildren extends FolderEntity {
	children?: FolderEntity[];
}

export default class Folder extends BaseItem {
	static tableName() {
		return 'folders';
	}

	static modelType() {
		return BaseModel.TYPE_FOLDER;
	}

	static newFolder(): FolderEntity {
		return {
			id: null,
			title: '',
		};
	}

	static fieldToLabel(field: string) {
		const fieldsToLabels: any = {
			title: _('title'),
			last_note_user_updated_time: _('updated date'),
		};

		return field in fieldsToLabels ? fieldsToLabels[field] : field;
	}

	static noteIds(parentId: string, options: any = null) {
		options = Object.assign({}, {
			includeConflicts: false,
		}, options);

		const where = ['parent_id = ?'];
		if (!options.includeConflicts) {
			where.push('is_conflict = 0');
		}

		return this.db()
			.selectAll(`SELECT id FROM notes WHERE ${where.join(' AND ')}`, [parentId])
			.then((rows: any[]) => {
				const output = [];
				for (let i = 0; i < rows.length; i++) {
					const row = rows[i];
					output.push(row.id);
				}
				return output;
			});
	}

	static async subFolderIds(parentId: string) {
		const rows = await this.db().selectAll('SELECT id FROM folders WHERE parent_id = ?', [parentId]);
		return rows.map((r: FolderEntity) => r.id);
	}

	static async noteCount(parentId: string) {
		const r = await this.db().selectOne('SELECT count(*) as total FROM notes WHERE is_conflict = 0 AND parent_id = ?', [parentId]);
		return r ? r.total : 0;
	}

	static markNotesAsConflict(parentId: string) {
		const query = Database.updateQuery('notes', { is_conflict: 1 }, { parent_id: parentId });
		return this.db().exec(query);
	}

	static async delete(folderId: string, options: any = null) {
		if (!options) options = {};
		if (!('deleteChildren' in options)) options.deleteChildren = true;

		const folder = await Folder.load(folderId);
		if (!folder) return; // noop

		if (options.deleteChildren) {
			const noteIds = await Folder.noteIds(folderId);
			await Note.batchDelete(noteIds);

			const subFolderIds = await Folder.subFolderIds(folderId);
			for (let i = 0; i < subFolderIds.length; i++) {
				await Folder.delete(subFolderIds[i]);
			}
		}

		await super.delete(folderId, options);

		this.dispatch({
			type: 'FOLDER_DELETE',
			id: folderId,
		});
	}

	static conflictFolderTitle() {
		return _('Conflicts');
	}

	static conflictFolderId() {
		return 'c04f1c7c04f1c7c04f1c7c04f1c7c04f';
	}

	static conflictFolder(): FolderEntity {
		return {
			type_: this.TYPE_FOLDER,
			id: this.conflictFolderId(),
			parent_id: '',
			title: this.conflictFolderTitle(),
			updated_time: time.unixMs(),
			user_updated_time: time.unixMs(),
		};
	}

	// Calculates note counts for all folders and adds the note_count attribute to each folder
	// Note: this only calculates the overall number of nodes for this folder and all its descendants
	static async addNoteCounts(folders: any[], includeCompletedTodos = true) {
		const foldersById: any = {};
		for (const f of folders) {
			foldersById[f.id] = f;

			if (this.conflictFolderId() === f.id) {
				f.note_count = await Note.conflictedCount();
			} else {
				f.note_count = 0;
			}
		}

		const where = ['is_conflict = 0'];
		if (!includeCompletedTodos) where.push('(notes.is_todo = 0 OR notes.todo_completed = 0)');

		const sql = `
			SELECT folders.id as folder_id, count(notes.parent_id) as note_count 
			FROM folders LEFT JOIN notes ON notes.parent_id = folders.id
			WHERE ${where.join(' AND ')}
			GROUP BY folders.id
		`;

		const noteCounts = await this.db().selectAll(sql);
		noteCounts.forEach((noteCount: any) => {
			let parentId = noteCount.folder_id;
			do {
				const folder = foldersById[parentId];
				if (!folder) break; // https://github.com/laurent22/joplin/issues/2079
				folder.note_count = (folder.note_count || 0) + noteCount.note_count;

				// Should not happen anymore but just to be safe, add the check below
				// https://github.com/laurent22/joplin/issues/3334
				if (folder.id === folder.parent_id) break;

				parentId = folder.parent_id;
			} while (parentId);
		});
	}

	// Folders that contain notes that have been modified recently go on top.
	// The remaining folders, that don't contain any notes are sorted by their own user_updated_time
	static async orderByLastModified(folders: FolderEntity[], dir = 'DESC') {
		dir = dir.toUpperCase();
		const sql = 'select parent_id, max(user_updated_time) content_updated_time from notes where parent_id != "" group by parent_id';
		const rows = await this.db().selectAll(sql);

		const folderIdToTime: Record<string, number> = {};
		for (let i = 0; i < rows.length; i++) {
			const row = rows[i];
			folderIdToTime[row.parent_id] = row.content_updated_time;
		}

		const findFolderParent = (folderId: string) => {
			const folder = BaseModel.byId(folders, folderId);
			if (!folder) return null; // For the rare case of notes that are associated with a no longer existing folder
			if (!folder.parent_id) return null;
			for (let i = 0; i < folders.length; i++) {
				if (folders[i].id === folder.parent_id) return folders[i];
			}

			// In some rare cases, some folders may not have a parent, for example
			// if it has not been downloaded via sync yet.
			// https://github.com/laurent22/joplin/issues/2088
			return null;
		};

		const applyChildTimeToParent = (folderId: string) => {
			const parent = findFolderParent(folderId);
			if (!parent) return;

			if (folderIdToTime[parent.id] && folderIdToTime[parent.id] >= folderIdToTime[folderId]) {
				// Don't change so that parent has the same time as the last updated child
			} else {
				folderIdToTime[parent.id] = folderIdToTime[folderId];
			}

			applyChildTimeToParent(parent.id);
		};

		for (const folderId in folderIdToTime) {
			if (!folderIdToTime.hasOwnProperty(folderId)) continue;
			applyChildTimeToParent(folderId);
		}

		const mod = dir === 'DESC' ? +1 : -1;
		const output = folders.slice();
		output.sort((a, b) => {
			const aTime = folderIdToTime[a.id] ? folderIdToTime[a.id] : a.user_updated_time;
			const bTime = folderIdToTime[b.id] ? folderIdToTime[b.id] : b.user_updated_time;

			if (aTime < bTime) return +1 * mod;
			if (aTime > bTime) return -1 * mod;

			return 0;
		});

		return output;
	}

	static async all(options: any = null) {
		const output = await super.all(options);
		if (options && options.includeConflictFolder) {
			const conflictCount = await Note.conflictedCount();
			if (conflictCount) output.push(this.conflictFolder());
		}
		return output;
	}

	static async childrenIds(folderId: string) {
		const folders = await this.db().selectAll('SELECT id FROM folders WHERE parent_id = ?', [folderId]);

		let output: string[] = [];

		for (let i = 0; i < folders.length; i++) {
			const f = folders[i];
			output.push(f.id);
			const subChildrenIds = await this.childrenIds(f.id);
			output = output.concat(subChildrenIds);
		}

		return output;
	}

	static async expandTree(folders: FolderEntity[], parentId: string) {
		const folderPath = await this.folderPath(folders, parentId);
		folderPath.pop(); // We don't expand the leaft notebook

		for (const folder of folderPath) {
			this.dispatch({
				type: 'FOLDER_SET_COLLAPSED',
				id: folder.id,
				collapsed: false,
			});
		}
	}

	static async allAsTree(folders: FolderEntity[] = null, options: any = null) {
		const all = folders ? folders : await this.all(options);

		// https://stackoverflow.com/a/49387427/561309
		function getNestedChildren(models: FolderEntityWithChildren[], parentId: string) {
			const nestedTreeStructure = [];
			const length = models.length;

			for (let i = 0; i < length; i++) {
				const model = models[i];

				if (model.parent_id == parentId) {
					const children = getNestedChildren(models, model.id);

					if (children.length > 0) {
						model.children = children;
					}

					nestedTreeStructure.push(model);
				}
			}

			return nestedTreeStructure;
		}

		return getNestedChildren(all, '');
	}

	static folderPath(folders: FolderEntity[], folderId: string) {
		const idToFolders: Record<string, FolderEntity> = {};
		for (let i = 0; i < folders.length; i++) {
			idToFolders[folders[i].id] = folders[i];
		}

		const path = [];
		while (folderId) {
			const folder = idToFolders[folderId];
			if (!folder) break; // Shouldn't happen
			path.push(folder);
			folderId = folder.parent_id;
		}

		path.reverse();

		return path;
	}

	static folderPathString(folders: FolderEntity[], folderId: string, maxTotalLength = 80) {
		const path = this.folderPath(folders, folderId);

		let currentTotalLength = 0;
		for (let i = 0; i < path.length; i++) {
			currentTotalLength += path[i].title.length;
		}

		let pieceLength = maxTotalLength;
		if (currentTotalLength > maxTotalLength) {
			pieceLength = maxTotalLength / path.length;
		}

		const output = [];
		for (let i = 0; i < path.length; i++) {
			output.push(substrWithEllipsis(path[i].title, 0, pieceLength));
		}

		return output.join(' / ');
	}

	static buildTree(folders: FolderEntity[]) {
		const idToFolders: Record<string, any> = {};
		for (let i = 0; i < folders.length; i++) {
			idToFolders[folders[i].id] = Object.assign({}, folders[i]);
			idToFolders[folders[i].id].children = [];
		}

		const rootFolders = [];
		for (const folderId in idToFolders) {
			if (!idToFolders.hasOwnProperty(folderId)) continue;

			const folder = idToFolders[folderId];
			if (!folder.parent_id) {
				rootFolders.push(folder);
			} else {
				if (!idToFolders[folder.parent_id]) {
					// It means the notebook is refering a folder that doesn't exist. In theory it shouldn't happen
					// but sometimes does - https://github.com/laurent22/joplin/issues/1068#issuecomment-450594708
					rootFolders.push(folder);
				} else {
					idToFolders[folder.parent_id].children.push(folder);
				}
			}
		}

		return rootFolders;
	}

	static async sortFolderTree(folders: FolderEntityWithChildren[] = null) {
		const output = folders ? folders : await this.allAsTree();

		const sortFoldersAlphabetically = (folders: FolderEntityWithChildren[]) => {
			folders.sort((a: FolderEntityWithChildren, b: FolderEntityWithChildren) => {
				if (a.parent_id === b.parent_id) {
					return a.title.localeCompare(b.title, undefined, { sensitivity: 'accent' });
				}
				return 0;
			});
			return folders;
		};

		const sortFolders = (folders: FolderEntityWithChildren[]) => {
			for (let i = 0; i < folders.length; i++) {
				const folder = folders[i];
				if (folder.children) {
					folder.children = sortFoldersAlphabetically(folder.children);
					sortFolders(folder.children);
				}
			}
			return folders;
		};

		sortFolders(sortFoldersAlphabetically(output));
		return output;
	}

	static load(id: string, _options: any = null): Promise<FolderEntity> {
		if (id == this.conflictFolderId()) return Promise.resolve(this.conflictFolder());
		return super.load(id);
	}

	static defaultFolder() {
		return this.modelSelectOne('SELECT * FROM folders ORDER BY created_time DESC LIMIT 1');
	}

	static async canNestUnder(folderId: string, targetFolderId: string) {
		if (folderId === targetFolderId) return false;

		const conflictFolderId = Folder.conflictFolderId();
		if (folderId == conflictFolderId || targetFolderId == conflictFolderId) return false;

		if (!targetFolderId) return true;

		while (true) {
			const folder = await Folder.load(targetFolderId);
			if (!folder.parent_id) break;
			if (folder.parent_id === folderId) return false;
			targetFolderId = folder.parent_id;
		}

		return true;
	}

	static async moveToFolder(folderId: string, targetFolderId: string) {
		if (!(await this.canNestUnder(folderId, targetFolderId))) throw new Error(_('Cannot move notebook to this location'));

		// When moving a note to a different folder, the user timestamp is not updated.
		// However updated_time is updated so that the note can be synced later on.

		const modifiedFolder = {
			id: folderId,
			parent_id: targetFolderId,
			updated_time: time.unixMs(),
		};

		return Folder.save(modifiedFolder, { autoTimestamp: false });
	}

	// These "duplicateCheck" and "reservedTitleCheck" should only be done when a user is
	// manually creating a folder. They shouldn't be done for example when the folders
	// are being synced to avoid any strange side-effects. Technically it's possible to
	// have folders and notes with duplicate titles (or no title), or with reserved words.
	static async save(o: FolderEntity, options: any = null) {
		if (!options) options = {};

		if (options.userSideValidation === true) {
			if (!('duplicateCheck' in options)) options.duplicateCheck = true;
			if (!('reservedTitleCheck' in options)) options.reservedTitleCheck = true;
			if (!('stripLeftSlashes' in options)) options.stripLeftSlashes = true;

			if (o.id && o.parent_id && o.id === o.parent_id) {
				throw new Error('Parent ID cannot be the same as ID');
			}
		}

		if (options.stripLeftSlashes === true && o.title) {
			while (o.title.length && (o.title[0] == '/' || o.title[0] == '\\')) {
				o.title = o.title.substr(1);
			}
		}

		// We allow folders with duplicate titles so that folders with the same title can exist under different parent folder. For example:
		//
		// PHP
		//     Code samples
		//     Doc
		// Java
		//     My project
		//     Doc

		// if (options.duplicateCheck === true && o.title) {
		// 	let existingFolder = await Folder.loadByTitle(o.title);
		// 	if (existingFolder && existingFolder.id != o.id) throw new Error(_('A notebook with this title already exists: "%s"', o.title));
		// }

		if (options.reservedTitleCheck === true && o.title) {
			if (o.title == Folder.conflictFolderTitle()) throw new Error(_('Notebooks cannot be named "%s", which is a reserved title.', o.title));
		}

		return super.save(o, options).then((folder: FolderEntity) => {
			this.dispatch({
				type: 'FOLDER_UPDATE_ONE',
				item: folder,
			});
			return folder;
		});
	}
}