import Joi from "joi";
import { FindOptions, WhereOptions, Op, IncludeOptions } from "sequelize";
import DataModuleJob from "./DataModuleJob";

export enum FilterType {
	REGEX = "regex",
	CONTAINS = "contains",
	EXACT = "exact",
	DATETIME_BEFORE = "datetimeBefore",
	DATETIME_AFTER = "datetimeAfter",
	NUMBER_LESSER_EQUAL = "numberLesserEqual",
	NUMBER_LESSER = "numberLesser",
	NUMBER_GREATER = "numberGreater",
	NUMBER_GREATER_EQUAL = "numberGreaterEqual",
	NUMBER_EQUAL = "numberEquals",
	BOOLEAN = "boolean",
	SPECIAL = "special"
}

interface Sort {
	[property: string]: "ascending" | "descending";
}

interface Query {
	filter: {
		property: string;
	};
	filterType: FilterType;
	data: string;
}

type Payload = {
	page: number;
	pageSize: number;
	properties: string[];
	sort: Sort;
	queries: Query[];
	operator: "and" | "or" | "nor";
};

export default abstract class GetDataJob extends DataModuleJob {
	protected static _payloadSchema = Joi.object({
		page: Joi.number().required(),
		pageSize: Joi.number().required(),
		properties: Joi.array()
			.items(Joi.string().required())
			.min(1)
			.required(),
		sort: Joi.object()
			.pattern(
				/^/,
				Joi.string().valid("ascending", "descending").required()
			)
			.required(),
		queries: Joi.array()
			.items(
				Joi.object({
					filter: Joi.object({
						name: Joi.string().optional(), // Remove eventually
						displayName: Joi.string().optional(), // Remove eventually
						property: Joi.string().required(),
						filterTypes: Joi.array()
							.items(
								Joi.string()
									.valid(...Object.values(FilterType))
									.required()
							)
							.optional(), // Remove eventually
						defaultFilterType: Joi.string()
							.valid(...Object.values(FilterType))
							.required() // Remove eventually
					}).required(),
					filterType: Joi.string()
						.valid(...Object.values(FilterType))
						.required(),
					data: Joi.alternatives()
						.try(
							Joi.boolean(),
							Joi.string()
							// Joi.number(),
						)
						.required()
				})
			)
			.required(),
		operator: Joi.string().valid("and", "or", "nor").required()
	});

	protected _blacklistedProperties?: string[];

	protected _specialFilters?: Record<
		string,
		(query: FindOptions, data: any) => FindOptions
	>;

	protected _specialProperties?: Record<
		string,
		(query: FindOptions) => FindOptions
	>;

	protected _specialQueries?: Record<
		string,
		(query: Record<string, WhereOptions>) => {
			query: WhereOptions;
			includeProperties: string[];
		}
	>;

	protected async _execute() {
		const { page, pageSize, properties, sort, queries, operator } = this
			._payload as Payload;

		let findQuery: FindOptions = {};

		// If a query filter property or sort property is blacklisted, throw error
		if (this._blacklistedProperties?.length) {
			if (
				queries.some(query =>
					this._blacklistedProperties!.some(blacklistedProperty =>
						blacklistedProperty.startsWith(query.filter.property)
					)
				)
			)
				throw new Error("Unable to filter by blacklisted property.");
			if (
				Object.keys(sort).some(property =>
					this._blacklistedProperties!.some(blacklistedProperty =>
						blacklistedProperty.startsWith(property)
					)
				)
			)
				throw new Error("Unable to sort by blacklisted property.");
		}

		// If a filter or property exists for a special property, add some custom pipeline steps
		if (this._specialProperties)
			Object.entries(this._specialProperties).forEach(
				([specialProperty, modifyQuery]) => {
					// Check if a filter with the special property exists
					const filterExists =
						queries
							.map(query => query.filter.property)
							.indexOf(specialProperty) !== -1;

					// Check if a property with the special property exists
					const propertyExists =
						properties.indexOf(specialProperty) !== -1;

					// If no such filter or property exists, skip this function
					if (!filterExists && !propertyExists) return;

					// Add the specified pipeline steps into the pipeline
					findQuery = modifyQuery(findQuery);
				}
			);

		// Properties that we need to include (join) with Sequelize, e.g. createdByModel
		const includePropertiesSet = new Set<string>();

		// Adds where stage to query, which is responsible for filtering
		const filterQueries = queries.flatMap(query => {
			const { data, filter, filterType } = query;
			const { property } = filter;

			const newQuery: any = {};
			switch (filterType) {
				case FilterType.REGEX:
					newQuery[property] = {
						[Op.iRegexp]: data
					};
					break;
				case FilterType.CONTAINS:
					newQuery[property] = {
						[Op.like]: `%${data}%`
					};
					break;
				case FilterType.EXACT:
					newQuery[property] = data.toString();
					break;
				case FilterType.DATETIME_BEFORE:
					newQuery[property] = { [Op.lte]: new Date(data) };
					break;
				case FilterType.DATETIME_AFTER:
					newQuery[property] = { [Op.gte]: new Date(data) };
					break;
				case FilterType.NUMBER_LESSER_EQUAL:
					newQuery[property] = { [Op.lte]: Number(data) };
					break;
				case FilterType.NUMBER_LESSER:
					newQuery[property] = { [Op.lt]: Number(data) };
					break;
				case FilterType.NUMBER_GREATER:
					newQuery[property] = { [Op.gt]: Number(data) };
					break;
				case FilterType.NUMBER_GREATER_EQUAL:
					newQuery[property] = { [Op.gte]: Number(data) };
					break;
				case FilterType.NUMBER_EQUAL:
					newQuery[property] = { [Op.eq]: Number(data) };
					break;
				case FilterType.BOOLEAN:
					newQuery[property] = { [Op.eq]: !!data };
					break;
				case FilterType.SPECIAL:
					if (
						typeof this._specialFilters?.[filter.property] ===
						"function"
					) {
						findQuery = this._specialFilters[filter.property](
							findQuery,
							data
						);
						newQuery[property] = { [Op.eq]: true };
					}
					break;
				default:
					throw new Error(`Invalid filter type for "${filter}"`);
			}

			if (typeof this._specialQueries?.[filter.property] === "function") {
				const { query, includeProperties } =
					this._specialQueries[filter.property](newQuery);

				// Keep track of what property/properties Sequelize will have to include (join) for the special query to work
				includeProperties.forEach(includeProperty => {
					includePropertiesSet.add(includeProperty);
				});

				return query;
			}

			return newQuery;
		});

		if (filterQueries.length > 0) {
			if (operator === "nor") {
				findQuery.where = {
					[Op.not]: {
						[Op.or]: filterQueries
					}
				};
			} else {
				findQuery.where = {
					[Op[operator]]: filterQueries
				};
			}
		}

		// Adds order stage to query if there is at least one column being sorted, responsible for sorting data
		if (Object.keys(sort).length > 0)
			findQuery.order = Object.entries(sort).map(
				([property, direction]) => [
					property,
					direction === "ascending" ? "ASC" : "DESC"
				]
			);

		findQuery.attributes = {
			include: properties,
			exclude: this._blacklistedProperties
		};
		findQuery.offset = pageSize * (page - 1);
		findQuery.limit = pageSize;

		// We need to tell Sequalize that some associated tables are used and must be included (joined)
		const includeProperties = Array.from(includePropertiesSet);
		findQuery.include = includeProperties.map(includeProperty => {
			const association = this.getModel().associations[includeProperty];
			const targetModel = association.target;

			return {
				model: targetModel, // E.g. User
				as: includeProperty, // e.g. "createdByModel"
				attributes: [] // We do not want to return any data from anything we include
			} as IncludeOptions;
		});

		// Executes the query
		const { rows, count } = await this.getModel().findAndCountAll(
			findQuery
		);

		// TODO make absolutely sure createdByModel and similar here have been removed or aren't included, if they've been included at all

		return { data: rows, count };
	}
}