import PostgrestBuilder from "./PostgrestBuilder";
import { GetResult } from "./select-query-parser";
import { GenericSchema } from "./types";

export default class PostgrestTransformBuilder<
	Schema extends GenericSchema,
	Row extends Record<string, unknown>,
	Result,
> extends PostgrestBuilder<Result> {
	/**
	 * Perform a SELECT on the query result.
	 *
	 * By default, `.insert()`, `.update()`, `.upsert()`, and `.delete()` do not
	 * return modified rows. By calling this method, modified rows are returned in
	 * `data`.
	 *
	 * @param columns - The columns to retrieve, separated by commas
	 */
	select<
		Query extends string = "*",
		NewResultOne = GetResult<Schema, Row, Query>,
	>(columns?: Query): PostgrestTransformBuilder<Schema, Row, NewResultOne[]> {
		// Remove whitespaces except when quoted
		let quoted = false;
		const cleanedColumns = (columns ?? "*")
			.split("")
			.map((c) => {
				if (/\s/.test(c) && !quoted) {
					return "";
				}
				if (c === '"') {
					quoted = !quoted;
				}
				return c;
			})
			.join("");
		this.url.searchParams.set("select", cleanedColumns);
		if (this.headers["Prefer"]) {
			this.headers["Prefer"] += ",";
		}
		this.headers["Prefer"] += "return=representation";
		return this as unknown as PostgrestTransformBuilder<
			Schema,
			Row,
			NewResultOne[]
		>;
	}

	order<ColumnName extends string & keyof Row>(
		column: ColumnName,
		options?: {
			ascending?: boolean;
			nullsFirst?: boolean;
			foreignTable?: undefined;
		},
	): this;
	order(
		column: string,
		options?: {
			ascending?: boolean;
			nullsFirst?: boolean;
			foreignTable: string;
		},
	): this;
	/**
	 * Order the query result by `column`.
	 *
	 * You can call this method multiple times to order by multiple columns.
	 *
	 * You can order foreign tables, but it doesn't affect the ordering of the
	 * current table.
	 *
	 * @param column - The column to order by
	 * @param options - Named parameters
	 * @param options.ascending - If `true`, the result will be in ascending order
	 * @param options.nullsFirst - If `true`, `null`s appear first. If `false`,
	 * `null`s appear last.
	 * @param options.foreignTable - Set this to order a foreign table by foreign
	 * columns
	 */
	order(
		column: string,
		{
			ascending = true,
			nullsFirst,
			foreignTable,
		}: {
			ascending?: boolean;
			nullsFirst?: boolean;
			foreignTable?: string;
		} = {},
	): this {
		const key = foreignTable ? `${foreignTable}.order` : "order";
		const existingOrder = this.url.searchParams.get(key);

		this.url.searchParams.set(
			key,
			`${existingOrder ? `${existingOrder},` : ""}${column}.${
				ascending ? "asc" : "desc"
			}${
				nullsFirst === undefined
					? ""
					: nullsFirst
					? ".nullsfirst"
					: ".nullslast"
			}`,
		);
		return this;
	}

	/**
	 * Limit the query result by `count`.
	 *
	 * @param count - The maximum number of rows to return
	 * @param options - Named parameters
	 * @param options.foreignTable - Set this to limit rows of foreign tables
	 * instead of the current table
	 */
	limit(count: number, { foreignTable }: { foreignTable?: string } = {}): this {
		const key =
			typeof foreignTable === "undefined" ? "limit" : `${foreignTable}.limit`;
		this.url.searchParams.set(key, `${count}`);
		return this;
	}

	/**
	 * Limit the query result by `from` and `to` inclusively.
	 *
	 * @param from - The starting index from which to limit the result
	 * @param to - The last index to which to limit the result
	 * @param options - Named parameters
	 * @param options.foreignTable - Set this to limit rows of foreign tables
	 * instead of the current table
	 */
	range(
		from: number,
		to: number,
		{ foreignTable }: { foreignTable?: string } = {},
	): this {
		const keyOffset =
			typeof foreignTable === "undefined" ? "offset" : `${foreignTable}.offset`;
		const keyLimit =
			typeof foreignTable === "undefined" ? "limit" : `${foreignTable}.limit`;
		this.url.searchParams.set(keyOffset, `${from}`);
		// Range is inclusive, so add 1
		this.url.searchParams.set(keyLimit, `${to - from + 1}`);
		return this;
	}

	/**
	 * Set the AbortSignal for the fetch request.
	 *
	 * @param signal - The AbortSignal to use for the fetch request
	 */
	abortSignal(signal: AbortSignal): this {
		this.signal = signal;
		return this;
	}

	/**
	 * Return `data` as a single object instead of an array of objects.
	 *
	 * Query result must be one row (e.g. using `.limit(1)`), otherwise this
	 * returns an error.
	 */
	single<
		ResultOne = Result extends (infer ResultOne)[] ? ResultOne : never,
	>(): PostgrestBuilder<ResultOne> {
		this.headers["Accept"] = "application/vnd.pgrst.object+json";
		return this as PostgrestBuilder<ResultOne>;
	}

	/**
	 * Return `data` as a single object instead of an array of objects.
	 *
	 * Query result must be zero or one row (e.g. using `.limit(1)`), otherwise
	 * this returns an error.
	 */
	maybeSingle<
		ResultOne = Result extends (infer ResultOne)[] ? ResultOne : never,
	>(): PostgrestBuilder<ResultOne | null> {
		this.headers["Accept"] = "application/vnd.pgrst.object+json";
		this.allowEmpty = true;
		return this as PostgrestBuilder<ResultOne | null>;
	}

	/**
	 * Return `data` as a string in CSV format.
	 */
	csv(): PostgrestBuilder<string> {
		this.headers["Accept"] = "text/csv";
		return this as PostgrestBuilder<string>;
	}

	/**
	 * Return `data` as an object in [GeoJSON](https://geojson.org) format.
	 */
	geojson(): PostgrestBuilder<Record<string, unknown>> {
		this.headers["Accept"] = "application/geo+json";
		return this as PostgrestBuilder<Record<string, unknown>>;
	}

	/**
	 * Return `data` as the EXPLAIN plan for the query.
	 *
	 * @param options - Named parameters
	 *
	 * @param options.analyze - If `true`, the query will be executed and the
	 * actual run time will be returned
	 *
	 * @param options.verbose - If `true`, the query identifier will be returned
	 * and `data` will include the output columns of the query
	 *
	 * @param options.settings - If `true`, include information on configuration
	 * parameters that affect query planning
	 *
	 * @param options.buffers - If `true`, include information on buffer usage
	 *
	 * @param options.wal - If `true`, include information on WAL record generation
	 *
	 * @param options.format - The format of the output, can be `"text"` (default)
	 * or `"json"`
	 */
	explain({
		analyze = false,
		verbose = false,
		settings = false,
		buffers = false,
		wal = false,
		format = "text",
	}: {
		analyze?: boolean;
		verbose?: boolean;
		settings?: boolean;
		buffers?: boolean;
		wal?: boolean;
		format?: "json" | "text";
	} = {}):
		| PostgrestBuilder<Record<string, unknown>[]>
		| PostgrestBuilder<string> {
		const options = [
			analyze ? "analyze" : null,
			verbose ? "verbose" : null,
			settings ? "settings" : null,
			buffers ? "buffers" : null,
			wal ? "wal" : null,
		]
			.filter(Boolean)
			.join("|");
		// An Accept header can carry multiple media types but postgrest-js always sends one
		const forMediatype = this.headers["Accept"];
		this.headers[
			"Accept"
		] = `application/vnd.pgrst.plan+${format}; for="${forMediatype}"; options=${options};`;
		if (format === "json")
			return this as PostgrestBuilder<Record<string, unknown>[]>;
		else return this as PostgrestBuilder<string>;
	}

	/**
	 * Rollback the query.
	 *
	 * `data` will still be returned, but the query is not committed.
	 */
	rollback(): this {
		if ((this.headers["Prefer"] ?? "").trim().length > 0) {
			this.headers["Prefer"] += ",tx=rollback";
		} else {
			this.headers["Prefer"] = "tx=rollback";
		}
		return this;
	}

	/**
	 * Override the type of the returned `data`.
	 *
	 * @typeParam NewResult - The new result type to override with
	 */
	returns<NewResult>(): PostgrestTransformBuilder<Schema, Row, NewResult> {
		return this as unknown as PostgrestTransformBuilder<Schema, Row, NewResult>;
	}
}