import "../core/metadata.ts";
import {
	defineMemberMetadata,
	getAllMemberMetadata,
} from "../core/metadata.ts";
import type { HttpMethod } from "../contracts/typegen/http/method.ts";
import { normalizeMethod } from "../contracts/typegen/http/method.ts";
import type { StatusCode } from "../contracts/typegen/http/respcode.ts";

/**
 * `@Route()` binds a controller method to an HTTP route.
 */
export const ROUTE_METADATA_KEY = "muddle:route";

export interface RouteOptions {
	/** HTTP method(s) handled by the route, defaults to `GET`. */
	method?: HttpMethod | HttpMethod[];
	/** Status code used when the handler returns a plain value. */
	status?: StatusCode;
	/** Route name, used by the fluent view helpers. */
	name?: string;
	/** Human-readable route description. */
	description?: string;
	/** Parameter description by parameter name. */
	params?: Record<string, string>;
}

export interface RouteMetadata {
	/** Path relative to the controller prefix. */
	path: string;
	method: HttpMethod;
	options: RouteOptions;
	/** Name of the decorated method. */
	propertyKey: string;
}

function normalizeMethods(method: RouteOptions["method"]): HttpMethod[] {
	if (method === undefined) return ["GET"];
	const list = Array.isArray(method) ? method : [method];
	return list.map((entry) => normalizeMethod(entry));
}

/** Declares one or more routes for a controller method. */
export function Route(
	path: string,
	options: RouteOptions = {},
): MethodDecorator {
	return (target, propertyKey, descriptor) => {
		for (const httpMethod of normalizeMethods(options.method)) {
			defineMemberMetadata(
				ROUTE_METADATA_KEY,
				{
					path,
					method: httpMethod,
					options,
					propertyKey: String(propertyKey),
				} satisfies RouteMetadata,
				target as object,
				propertyKey as string,
			);
		}
		return descriptor;
	};
}

/**
 * Reads every route declared on a controller class.
 *
 * When a property key is given, only the routes of that method are returned.
 */
export function getRoutes(
	target: object,
	propertyKey?: string,
): RouteMetadata[] {
	return getAllMemberMetadata(ROUTE_METADATA_KEY, target)
		.filter(
			(entry) => propertyKey === undefined || entry.propertyKey === propertyKey,
		)
		.map((entry) => entry.value as RouteMetadata);
}