const BaseModel = require("lib/BaseModel.js");
const { Database } = require("lib/database.js");
const Setting = require("lib/models/Setting.js");
const JoplinError = require("lib/JoplinError.js");
const { time } = require("lib/time-utils.js");
const { sprintf } = require("sprintf-js");
const { _ } = require("lib/locale.js");
const moment = require("moment");

class BaseItem extends BaseModel {
	static useUuid() {
		return true;
	}

	static encryptionSupported() {
		return true;
	}

	static loadClass(className, classRef) {
		for (let i = 0; i < BaseItem.syncItemDefinitions_.length; i++) {
			if (BaseItem.syncItemDefinitions_[i].className == className) {
				BaseItem.syncItemDefinitions_[i].classRef = classRef;
				return;
			}
		}

		throw new Error("Invalid class name: " + className);
	}

	// Need to dynamically load the classes like this to avoid circular dependencies
	static getClass(name) {
		for (let i = 0; i < BaseItem.syncItemDefinitions_.length; i++) {
			if (BaseItem.syncItemDefinitions_[i].className == name) {
				const classRef = BaseItem.syncItemDefinitions_[i].classRef;
				if (!classRef) throw new Error("Class has not been loaded: " + name);
				return BaseItem.syncItemDefinitions_[i].classRef;
			}
		}

		throw new Error("Invalid class name: " + name);
	}

	static getClassByItemType(itemType) {
		for (let i = 0; i < BaseItem.syncItemDefinitions_.length; i++) {
			if (BaseItem.syncItemDefinitions_[i].type == itemType) {
				return BaseItem.syncItemDefinitions_[i].classRef;
			}
		}

		throw new Error("Invalid item type: " + itemType);
	}

	static async syncedCount(syncTarget) {
		const ItemClass = this.itemClass(this.modelType());
		const itemType = ItemClass.modelType();
		// The fact that we don't check if the item_id still exist in the corresponding item table, means
		// that the returned number might be innaccurate (for example if a sync operation was cancelled)
		const sql = "SELECT count(*) as total FROM sync_items WHERE sync_target = ? AND item_type = ?";
		const r = await this.db().selectOne(sql, [syncTarget, itemType]);
		return r.total;
	}

	static systemPath(itemOrId) {
		if (typeof itemOrId === "string") return itemOrId + ".md";
		return itemOrId.id + ".md";
	}

	static isSystemPath(path) {
		// 1b175bb38bba47baac22b0b47f778113.md
		if (!path || !path.length) return false;
		let p = path.split("/");
		p = p[p.length - 1];
		p = p.split(".");
		if (p.length != 2) return false;
		return p[0].length == 32 && p[1] == "md";
	}

	static itemClass(item) {
		if (!item) throw new Error("Item cannot be null");

		if (typeof item === "object") {
			if (!("type_" in item)) throw new Error("Item does not have a type_ property");
			return this.itemClass(item.type_);
		} else {
			for (let i = 0; i < BaseItem.syncItemDefinitions_.length; i++) {
				let d = BaseItem.syncItemDefinitions_[i];
				if (Number(item) == d.type) return this.getClass(d.className);
			}
			throw new Error("Unknown type: " + item);
		}
	}

	// Returns the IDs of the items that have been synced at least once
	static async syncedItemIds(syncTarget) {
		if (!syncTarget) throw new Error("No syncTarget specified");
		let temp = await this.db().selectAll("SELECT item_id FROM sync_items WHERE sync_time > 0 AND sync_target = ?", [syncTarget]);
		let output = [];
		for (let i = 0; i < temp.length; i++) {
			output.push(temp[i].item_id);
		}
		return output;
	}

	static pathToId(path) {
		let p = path.split("/");
		let s = p[p.length - 1].split(".");
		return s[0];
	}

	static loadItemByPath(path) {
		return this.loadItemById(this.pathToId(path));
	}

	static async loadItemById(id) {
		let classes = this.syncItemClassNames();
		for (let i = 0; i < classes.length; i++) {
			let item = await this.getClass(classes[i]).load(id);
			if (item) return item;
		}
		return null;
	}

	static loadItemByField(itemType, field, value) {
		let ItemClass = this.itemClass(itemType);
		return ItemClass.loadByField(field, value);
	}

	static loadItem(itemType, id) {
		let ItemClass = this.itemClass(itemType);
		return ItemClass.load(id);
	}

	static deleteItem(itemType, id) {
		let ItemClass = this.itemClass(itemType);
		return ItemClass.delete(id);
	}

	static async delete(id, options = null) {
		return this.batchDelete([id], options);
	}

	static async batchDelete(ids, options = null) {
		let trackDeleted = true;
		if (options && options.trackDeleted !== null && options.trackDeleted !== undefined) trackDeleted = options.trackDeleted;

		// Don't create a deleted_items entry when conflicted notes are deleted
		// since no other client have (or should have) them.
		let conflictNoteIds = [];
		if (this.modelType() == BaseModel.TYPE_NOTE) {
			const conflictNotes = await this.db().selectAll('SELECT id FROM notes WHERE id IN ("' + ids.join('","') + '") AND is_conflict = 1');
			conflictNoteIds = conflictNotes.map(n => {
				return n.id;
			});
		}

		await super.batchDelete(ids, options);

		if (trackDeleted) {
			const syncTargetIds = Setting.enumOptionValues("sync.target");
			let queries = [];
			let now = time.unixMs();
			for (let i = 0; i < ids.length; i++) {
				if (conflictNoteIds.indexOf(ids[i]) >= 0) continue;

				// For each deleted item, for each sync target, we need to add an entry in deleted_items.
				// That way, each target can later delete the remote item.
				for (let j = 0; j < syncTargetIds.length; j++) {
					queries.push({
						sql: "INSERT INTO deleted_items (item_type, item_id, deleted_time, sync_target) VALUES (?, ?, ?, ?)",
						params: [this.modelType(), ids[i], now, syncTargetIds[j]],
					});
				}
			}
			await this.db().transactionExecBatch(queries);
		}
	}

	// Note: Currently, once a deleted_items entry has been processed, it is removed from the database. In practice it means that
	// the following case will not work as expected:
	// - Client 1 creates a note and sync with target 1 and 2
	// - Client 2 sync with target 1
	// - Client 2 deletes note and sync with target 1
	// - Client 1 syncs with target 1 only (note is deleted from local machine, as expected)
	// - Client 1 syncs with target 2 only => the note is *not* deleted from target 2 because no information
	//   that it was previously deleted exist (deleted_items entry has been deleted).
	// The solution would be to permanently store the list of deleted items on each client.
	static deletedItems(syncTarget) {
		return this.db().selectAll("SELECT * FROM deleted_items WHERE sync_target = ?", [syncTarget]);
	}

	static async deletedItemCount(syncTarget) {
		let r = await this.db().selectOne("SELECT count(*) as total FROM deleted_items WHERE sync_target = ?", [syncTarget]);
		return r["total"];
	}

	static remoteDeletedItem(syncTarget, itemId) {
		return this.db().exec("DELETE FROM deleted_items WHERE item_id = ? AND sync_target = ?", [itemId, syncTarget]);
	}

	static serialize_format(propName, propValue) {
		if (["created_time", "updated_time", "sync_time", "user_updated_time", "user_created_time"].indexOf(propName) >= 0) {
			if (!propValue) return "";
			propValue =
				moment
					.unix(propValue / 1000)
					.utc()
					.format("YYYY-MM-DDTHH:mm:ss.SSS") + "Z";
		} else if (propValue === null || propValue === undefined) {
			propValue = "";
		}

		return propValue;
	}

	static unserialize_format(type, propName, propValue) {
		if (propName[propName.length - 1] == "_") return propValue; // Private property

		let ItemClass = this.itemClass(type);

		if (["created_time", "updated_time", "user_created_time", "user_updated_time"].indexOf(propName) >= 0) {
			if (!propValue) return 0;
			propValue = moment(propValue, "YYYY-MM-DDTHH:mm:ss.SSSZ").format("x");
		} else {
			propValue = Database.formatValue(ItemClass.fieldType(propName), propValue);
		}

		return propValue;
	}

	static async serialize(item, type = null, shownKeys = null) {
		item = this.filter(item);

		let output = {};

		if ("title" in item && shownKeys.indexOf("title") >= 0) {
			output.title = item.title;
		}

		if ("body" in item && shownKeys.indexOf("body") >= 0) {
			output.body = item.body;
		}

		output.props = [];

		for (let i = 0; i < shownKeys.length; i++) {
			let key = shownKeys[i];
			if (key == "title" || key == "body") continue;

			let value = null;
			if (typeof key === "function") {
				let r = await key();
				key = r.key;
				value = r.value;
			} else {
				value = this.serialize_format(key, item[key]);
			}

			output.props.push(key + ": " + value);
		}

		let temp = [];

		if (output.title) temp.push(output.title);
		if (output.body) temp.push(output.body);
		if (output.props.length) temp.push(output.props.join("\n"));

		return temp.join("\n\n");
	}

	static encryptionService() {
		if (!this.encryptionService_) throw new Error("BaseItem.encryptionService_ is not set!!");
		return this.encryptionService_;
	}

	static async serializeForSync(item) {
		const ItemClass = this.itemClass(item);
		let serialized = await ItemClass.serialize(item);
		if (!Setting.value("encryption.enabled") || !ItemClass.encryptionSupported()) {
			// Normally not possible since itemsThatNeedSync should only return decrypted items
			if (!!item.encryption_applied) throw new JoplinError("Item is encrypted but encryption is currently disabled", "cannotSyncEncrypted");
			return serialized;
		}

		if (!!item.encryption_applied) {
			const e = new Error("Trying to encrypt item that is already encrypted");
			e.code = "cannotEncryptEncrypted";
			throw e;
		}

		const cipherText = await this.encryptionService().encryptString(serialized);

		// List of keys that won't be encrypted - mostly foreign keys required to link items
		// with each others and timestamp required for synchronisation.
		const keepKeys = ["id", "note_id", "tag_id", "parent_id", "updated_time", "type_"];
		const reducedItem = {};

		for (let i = 0; i < keepKeys.length; i++) {
			const n = keepKeys[i];
			if (!item.hasOwnProperty(n)) continue;
			reducedItem[n] = item[n];
		}

		reducedItem.encryption_applied = 1;
		reducedItem.encryption_cipher_text = cipherText;

		return ItemClass.serialize(reducedItem);
	}

	static async decrypt(item) {
		if (!item.encryption_cipher_text) throw new Error("Item is not encrypted: " + item.id);

		const ItemClass = this.itemClass(item);
		const plainText = await this.encryptionService().decryptString(item.encryption_cipher_text);

		// Note: decryption does not count has a change, so don't update any timestamp
		const plainItem = await ItemClass.unserialize(plainText);
		plainItem.updated_time = item.updated_time;
		plainItem.encryption_cipher_text = "";
		plainItem.encryption_applied = 0;
		return ItemClass.save(plainItem, { autoTimestamp: false });
	}

	static async unserialize(content) {
		let lines = content.split("\n");
		let output = {};
		let state = "readingProps";
		let body = [];

		for (let i = lines.length - 1; i >= 0; i--) {
			let line = lines[i];

			if (state == "readingProps") {
				line = line.trim();

				if (line == "") {
					state = "readingBody";
					continue;
				}

				let p = line.indexOf(":");
				if (p < 0) throw new Error("Invalid property format: " + line + ": " + content);
				let key = line.substr(0, p).trim();
				let value = line.substr(p + 1).trim();
				output[key] = value;
			} else if (state == "readingBody") {
				body.splice(0, 0, line);
			}
		}

		if (!output.type_) throw new Error("Missing required property: type_: " + content);
		output.type_ = Number(output.type_);

		if (body.length) {
			let title = body.splice(0, 2);
			output.title = title[0];
		}

		if (output.type_ === BaseModel.TYPE_NOTE) output.body = body.join("\n");

		for (let n in output) {
			if (!output.hasOwnProperty(n)) continue;
			output[n] = await this.unserialize_format(output.type_, n, output[n]);
		}

		return output;
	}

	static async encryptedItemsStats() {
		const classNames = this.encryptableItemClassNames();
		let encryptedCount = 0;
		let totalCount = 0;

		for (let i = 0; i < classNames.length; i++) {
			const ItemClass = this.getClass(classNames[i]);
			encryptedCount += await ItemClass.count({ where: "encryption_applied = 1" });
			totalCount += await ItemClass.count();
		}

		return {
			encrypted: encryptedCount,
			total: totalCount,
		};
	}

	static async encryptedItemsCount() {
		const classNames = this.encryptableItemClassNames();
		let output = 0;

		for (let i = 0; i < classNames.length; i++) {
			const className = classNames[i];
			const ItemClass = this.getClass(className);
			const count = await ItemClass.count({ where: "encryption_applied = 1" });
			output += count;
		}

		return output;
	}

	static async hasEncryptedItems() {
		const classNames = this.encryptableItemClassNames();

		for (let i = 0; i < classNames.length; i++) {
			const className = classNames[i];
			const ItemClass = this.getClass(className);

			const count = await ItemClass.count({ where: "encryption_applied = 1" });
			if (count) return true;
		}

		return false;
	}

	static async itemsThatNeedDecryption(exclusions = [], limit = 100) {
		const classNames = this.encryptableItemClassNames();

		for (let i = 0; i < classNames.length; i++) {
			const className = classNames[i];
			const ItemClass = this.getClass(className);

			const whereSql = className === "Resource" ? ["(encryption_blob_encrypted = 1 OR encryption_applied = 1)"] : ["encryption_applied = 1"];
			if (exclusions.length) whereSql.push('id NOT IN ("' + exclusions.join('","') + '")');

			const sql = sprintf(
				`
				SELECT *
				FROM %s
				WHERE %s
				LIMIT %d
				`,
				this.db().escapeField(ItemClass.tableName()),
				whereSql.join(" AND "),
				limit
			);

			const items = await ItemClass.modelSelectAll(sql);

			if (i >= classNames.length - 1) {
				return { hasMore: items.length >= limit, items: items };
			} else {
				if (items.length) return { hasMore: true, items: items };
			}
		}

		throw new Error("Unreachable");
	}

	static async itemsThatNeedSync(syncTarget, limit = 100) {
		const classNames = this.syncItemClassNames();

		for (let i = 0; i < classNames.length; i++) {
			const className = classNames[i];
			const ItemClass = this.getClass(className);
			let fieldNames = ItemClass.fieldNames("items");

			// // NEVER SYNCED:
			// 'SELECT * FROM [ITEMS] WHERE id NOT INT (SELECT item_id FROM sync_items WHERE sync_target = ?)'

			// // CHANGED:
			// 'SELECT * FROM [ITEMS] items JOIN sync_items s ON s.item_id = items.id WHERE sync_target = ? AND'

			let extraWhere = [];
			if (className == "Note") extraWhere.push("is_conflict = 0");
			if (className == "Resource") extraWhere.push("encryption_blob_encrypted = 0");
			if (ItemClass.encryptionSupported()) extraWhere.push("encryption_applied = 0");

			extraWhere = extraWhere.length ? "AND " + extraWhere.join(" AND ") : "";

			// First get all the items that have never been synced under this sync target

			let sql = sprintf(
				`
				SELECT %s
				FROM %s items
				WHERE id NOT IN (
					SELECT item_id FROM sync_items WHERE sync_target = %d
				)
				%s
				LIMIT %d
			`,
				this.db().escapeFields(fieldNames),
				this.db().escapeField(ItemClass.tableName()),
				Number(syncTarget),
				extraWhere,
				limit
			);

			let neverSyncedItem = await ItemClass.modelSelectAll(sql);

			// Secondly get the items that have been synced under this sync target but that have been changed since then

			const newLimit = limit - neverSyncedItem.length;

			let changedItems = [];

			if (newLimit > 0) {
				fieldNames.push("sync_time");

				let sql = sprintf(
					`
					SELECT %s FROM %s items
					JOIN sync_items s ON s.item_id = items.id
					WHERE sync_target = %d
					AND (s.sync_time < items.updated_time OR force_sync = 1)
					AND s.sync_disabled = 0
					%s
					LIMIT %d
				`,
					this.db().escapeFields(fieldNames),
					this.db().escapeField(ItemClass.tableName()),
					Number(syncTarget),
					extraWhere,
					newLimit
				);

				changedItems = await ItemClass.modelSelectAll(sql);
			}

			const items = neverSyncedItem.concat(changedItems);

			if (i >= classNames.length - 1) {
				return { hasMore: items.length >= limit, items: items };
			} else {
				if (items.length) return { hasMore: true, items: items };
			}
		}

		throw new Error("Unreachable");
	}

	static syncItemClassNames() {
		return BaseItem.syncItemDefinitions_.map(def => {
			return def.className;
		});
	}

	static encryptableItemClassNames() {
		const temp = this.syncItemClassNames();
		let output = [];
		for (let i = 0; i < temp.length; i++) {
			if (temp[i] === "MasterKey") continue;
			output.push(temp[i]);
		}
		return output;
	}

	static syncItemTypes() {
		return BaseItem.syncItemDefinitions_.map(def => {
			return def.type;
		});
	}

	static modelTypeToClassName(type) {
		for (let i = 0; i < BaseItem.syncItemDefinitions_.length; i++) {
			if (BaseItem.syncItemDefinitions_[i].type == type) return BaseItem.syncItemDefinitions_[i].className;
		}
		throw new Error("Invalid type: " + type);
	}

	static async syncDisabledItems(syncTargetId) {
		const rows = await this.db().selectAll("SELECT * FROM sync_items WHERE sync_disabled = 1 AND sync_target = ?", [syncTargetId]);
		let output = [];
		for (let i = 0; i < rows.length; i++) {
			const item = await this.loadItem(rows[i].item_type, rows[i].item_id);
			if (!item) continue; // The referenced item no longer exist
			output.push({
				syncInfo: rows[i],
				item: item,
			});
		}
		return output;
	}

	static updateSyncTimeQueries(syncTarget, item, syncTime, syncDisabled = false, syncDisabledReason = "") {
		const itemType = item.type_;
		const itemId = item.id;
		if (!itemType || !itemId || syncTime === undefined) throw new Error("Invalid parameters in updateSyncTimeQueries()");

		return [
			{
				sql: "DELETE FROM sync_items WHERE sync_target = ? AND item_type = ? AND item_id = ?",
				params: [syncTarget, itemType, itemId],
			},
			{
				sql: "INSERT INTO sync_items (sync_target, item_type, item_id, sync_time, sync_disabled, sync_disabled_reason) VALUES (?, ?, ?, ?, ?, ?)",
				params: [syncTarget, itemType, itemId, syncTime, syncDisabled ? 1 : 0, syncDisabledReason + ""],
			},
		];
	}

	static async saveSyncTime(syncTarget, item, syncTime) {
		const queries = this.updateSyncTimeQueries(syncTarget, item, syncTime);
		return this.db().transactionExecBatch(queries);
	}

	static async saveSyncDisabled(syncTargetId, item, syncDisabledReason) {
		const syncTime = "sync_time" in item ? item.sync_time : 0;
		const queries = this.updateSyncTimeQueries(syncTargetId, item, syncTime, true, syncDisabledReason);
		return this.db().transactionExecBatch(queries);
	}

	// When an item is deleted, its associated sync_items data is not immediately deleted for
	// performance reason. So this function is used to look for these remaining sync_items and
	// delete them.
	static async deleteOrphanSyncItems() {
		const classNames = this.syncItemClassNames();

		let queries = [];
		for (let i = 0; i < classNames.length; i++) {
			const className = classNames[i];
			const ItemClass = this.getClass(className);

			let selectSql = "SELECT id FROM " + ItemClass.tableName();
			if (ItemClass.modelType() == this.TYPE_NOTE) selectSql += " WHERE is_conflict = 0";

			queries.push("DELETE FROM sync_items WHERE item_type = " + ItemClass.modelType() + " AND item_id NOT IN (" + selectSql + ")");
		}

		await this.db().transactionExecBatch(queries);
	}

	static displayTitle(item) {
		if (!item) return "";
		return !!item.encryption_applied ? "🔑 " + _("Encrypted") : item.title + "";
	}

	static async markAllNonEncryptedForSync() {
		const classNames = this.encryptableItemClassNames();

		for (let i = 0; i < classNames.length; i++) {
			const className = classNames[i];
			const ItemClass = this.getClass(className);

			const sql = sprintf(
				`
				SELECT id
				FROM %s
				WHERE encryption_applied = 0`,
				this.db().escapeField(ItemClass.tableName())
			);

			const items = await ItemClass.modelSelectAll(sql);
			const ids = items.map(item => {
				return item.id;
			});
			if (!ids.length) continue;

			await this.db().exec('UPDATE sync_items SET force_sync = 1 WHERE item_id IN ("' + ids.join('","') + '")');
		}
	}

	static async forceSync(itemId) {
		await this.db().exec("UPDATE sync_items SET force_sync = 1 WHERE item_id = ?", [itemId]);
	}

	static async forceSyncAll() {
		await this.db().exec("UPDATE sync_items SET force_sync = 1");
	}

	static async save(o, options = null) {
		if (!options) options = {};

		if (options.userSideValidation === true) {
			if (!!o.encryption_applied) throw new Error(_("Encrypted items cannot be modified"));
		}

		return super.save(o, options);
	}
}

BaseItem.encryptionService_ = null;

// Also update:
// - itemsThatNeedSync()
// - syncedItems()

BaseItem.syncItemDefinitions_ = [
	{ type: BaseModel.TYPE_NOTE, className: "Note" },
	{ type: BaseModel.TYPE_FOLDER, className: "Folder" },
	{ type: BaseModel.TYPE_RESOURCE, className: "Resource" },
	{ type: BaseModel.TYPE_TAG, className: "Tag" },
	{ type: BaseModel.TYPE_NOTE_TAG, className: "NoteTag" },
	{ type: BaseModel.TYPE_MASTER_KEY, className: "MasterKey" },
];

module.exports = BaseItem;