arg.ts

// Copyright 2020 Liam Tan. All rights reserved. MIT license.

import { ArgsType, ControllerMetadata } from "./types.ts";
import { setControllerMeta, getControllerMeta, defaultMetadata } from "./metadata.ts";

//import { Reflect } from "./lib/reflect.ts";

/**
 * Curried function responsible for generating parameter decorators
 * for controller actions.
 */
export const defineParameterDecorator = (
  argType: ArgsType,
  paramKey?: string
): ParameterDecorator => (
  target: any,
  propertyKey: string | Symbol,
  parameterIndex: number
): void => {
  const meta: ControllerMetadata = getControllerMeta(target) ?? defaultMetadata();
  meta.args.push({
    type: argType,
    key: paramKey,
    index: parameterIndex,
    argFor: propertyKey,
  });
  setControllerMeta(target, meta);
};

/**
 * Parameter decorator - maps `context.params` onto controller actions
 * as an argument, e.g.
 *
 * ```ts
 * public controllerAction(@Param('id') id: number): any {}
 * ```
 *
 * Returns whole `context.params` object if no key specified
 */
export function Param(paramKey?: string): ParameterDecorator {
  return defineParameterDecorator(ArgsType.PARAM, paramKey);
}
/**
 * Parameter decorator - maps `context.request.body()` onto controller actions
 * as an argument, e.g.
 *
 * ```ts
 * public controllerAction(@Body('name') name: string): any { }
 * ```
 *
 * Returns whole `context.request.body()` if no key specified
 */
export function Body(bodyKey?: string): ParameterDecorator {
  return defineParameterDecorator(ArgsType.BODY, bodyKey);
}
/**
 * Parameter decorator - maps `url.searchParams.entries()` onto controller actions
 * as an argument, e.g.
 *
 * ```ts
 * public controllerAction(@Query('orderBy') orderBy: string): any { }
 * ```
 *
 * Returns whole `url.searchParams.entries()` if no key specified.
 */
export function Query(queryKey?: string): ParameterDecorator {
  return defineParameterDecorator(ArgsType.QUERY, queryKey);
}
/**
 * Parameter decorator - maps `context.request.headers` onto controller actions
 * as an argument, e.g.
 *
 * ```ts
 * public controllerAction(@Header('content-type') contentType: string): any { }
 * ```
 * Returns whole `context.request.headers` if no key specified
 */
export function Header(headerKey?: string): ParameterDecorator {
  return defineParameterDecorator(ArgsType.HEADER, headerKey);
}
/**
 * Parameter decorator - maps whole `context` onto controller actions
 * as an argument, e.g.
 *
 * ```ts
 * public controllerAction(@Context() ctx: RouterContext): any { }
 * ```
 */
export function Context(): ParameterDecorator {
  return defineParameterDecorator(ArgsType.CONTEXT);
}
/**
 * Parameter decorator - maps `context.request` onto controller actions
 * as an argument, e.g.
 *
 * ```ts
 * public controllerAction(@Request() req: Request): any { }
 * ```
 */
export function Request(): ParameterDecorator {
  return defineParameterDecorator(ArgsType.REQUEST);
}
/**
 * Parameter decorator - maps `context.response` onto controller actions
 * as an argument, e.g.
 *
 * ```ts
 * public controllerAction(@Response() res: Response): any { }
 * ```
 */
export function Response(): ParameterDecorator {
  return defineParameterDecorator(ArgsType.RESPONSE);
}
/**
 * Parameter decorator - maps dependency by key from DI container
 * to a method argument
 *
 * ```ts
 * public controllerAction(@Inject() userService: UserService): any { }
 * ```
 */
export function Inject(key: string): ParameterDecorator {
  return defineParameterDecorator(ArgsType.INJECT, key);
}