import * as Effect from "effect/Effect";
import * as Binding from "../../Binding.ts";
import { isBindingHost } from "../Lambda/Function.ts";
import type { Room } from "./Room.ts";

/**
 * Shared scaffolding for Amazon IVS Chat HTTP bindings.
 *
 * NOT exported from `index.ts` — every thin `{Op}Http.ts` in this service is
 * a `Layer.effect(Cap, makeIvsChatRoomHttpBinding({ … }))` over the builder
 * below. Everything except the operation, the IAM action list, and an
 * optional request-shape mapper is boilerplate.
 */

/**
 * Build the impl Effect for an IVS Chat data-plane operation scoped to a
 * {@link Room}: the deploy-time half grants `actions` on the bound room's
 * ARN, and the runtime half injects the room's ARN as the `roomIdentifier`
 * of every request.
 *
 * `prepare` (optional) maps a friendlier public request shape onto the wire
 * request — e.g. `CreateChatToken` converts a `Duration.Input` into the wire
 * `sessionDurationInMinutes`. It defaults to identity.
 */
export const makeIvsChatRoomHttpBinding = <
  I extends { roomIdentifier: string },
  A,
  E,
  R,
  Req = Omit<I, "roomIdentifier">,
>(options: {
  /** Fully-qualified binding tag, e.g. `AWS.IVSChat.SendEvent`. */
  tag: string;
  /** The distilled operation. */
  operation: Effect.Effect<(input: I) => Effect.Effect<A, E>, never, R>;
  /** IAM actions granted on the room ARN. */
  actions: readonly string[];
  /** Map the public request shape to the wire request (defaults to identity). */
  prepare?: (request: Req) => Omit<I, "roomIdentifier">;
}) =>
  Effect.gen(function* () {
    const op = yield* options.operation;

    return Effect.fn(function* (room: Room) {
      // Output yields a DEFERRED effect — resolve again per invocation below.
      const RoomArn = yield* room.roomArn;
      if (!globalThis.__ALCHEMY_RUNTIME__) {
        const host = yield* Binding.Host;
        if (isBindingHost(host)) {
          yield* host.bind`Allow(${host}, ${options.tag}(${room}))`({
            policyStatements: [
              {
                Effect: "Allow",
                Action: [...options.actions],
                Resource: [room.roomArn],
              },
            ],
          });
        }
      }
      return Effect.fn(`${options.tag}(${room.LogicalId})`)(function* (
        request: Req,
      ) {
        const roomIdentifier = yield* RoomArn;
        const wire = options.prepare
          ? options.prepare(request)
          : (request as unknown as Omit<I, "roomIdentifier">);
        return yield* op({ ...wire, roomIdentifier } as I);
      });
    });
  });