import "../core/metadata.ts";
import { defineMemberMetadata, getAllMemberMetadata } from "../core/metadata.ts";
import { callerFile } from "../core/paths.ts";
import { dirname } from "node:path";
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";

export const VIEW_METADATA_KEY = "muddle:view";

export interface ViewOptions {
	/** HTTP method of the route, defaults to `GET`. */
	method?: HttpMethod | HttpMethod[];
	/** Route path, derived from the template when omitted. */
	path?: string;
	/** Status code of the response. */
	status?: StatusCode;
	name?: string;
	description?: string;
	params?: Record<string, string>;
}

export interface ViewMetadata {
	/** Name of the method the view belongs to. */
	propertyKey: string;
	/** Path of the template, relative to the view folder. */
	path: string;
	/** Directory of the file that declared the view. */
	dir: string;
	method: HttpMethod;
	status?: StatusCode;
	name?: string;
	description?: string;
	params?: Record<string, string>;
}

/** Declares the template rendered by a controller method. */
export function View(path?: string, options: ViewOptions = {}): MethodDecorator {
	return (target, propertyKey, descriptor) => {
		const caller = callerFile();
		const method = String(propertyKey);
		const methods = options.method
			? Array.isArray(options.method)
				? options.method
				: [options.method]
			: ["GET" as HttpMethod];

		for (const httpMethod of methods) {
			defineMemberMetadata(
				VIEW_METADATA_KEY,
				{
					propertyKey: method,
					path: path ?? `./${method}.spug`,
					dir: caller ? dirname(caller) : process.cwd(),
					method: normalizeMethod(httpMethod),
					status: options.status,
					name: options.name,
					description: options.description,
					params: options.params,
				} satisfies ViewMetadata,
				target as object,
				propertyKey as string,
			);
		}
		return descriptor;
	};
}

/**
 * Reads the view metadata of a controller class.
 *
 * When a property key is given, only the views of that method are returned.
 */
export function getViews(
	target: object,
	propertyKey?: string,
): ViewMetadata[] {
	return getAllMemberMetadata(VIEW_METADATA_KEY, target)
		.filter(
			(entry) => propertyKey === undefined || entry.propertyKey === propertyKey,
		)
		.map((entry) => entry.value as ViewMetadata);
}