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

/**
 * Shared scaffolding for CloudWatch Synthetics HTTP bindings.
 *
 * NOT exported from `index.ts` — every `{Op}Http.ts` in this service is a
 * thin `Layer.effect(Cap, make…HttpBinding({ … }))` over one of the two
 * builders below. Everything except the operation and the IAM action is
 * boilerplate:
 *
 * - {@link makeSyntheticsCanaryHttpBinding} — operations scoped to one bound
 *   {@link Canary} (`GetCanary`, `GetCanaryRuns`, `StartCanary`,
 *   `StopCanary`). The runtime callable injects the canary's name as the
 *   request's `Name`; the deploy-time half grants `actions` on the canary
 *   ARN.
 * - {@link makeSyntheticsAccountHttpBinding} — account-level operations
 *   (`DescribeCanariesLastRun`), granted on `*`.
 */

/**
 * Build the impl Effect for an operation scoped to a single bound
 * {@link Canary}. The runtime callable injects the canary's name as the
 * request's `Name`; the deploy-time half grants `actions` on the canary ARN.
 */
export const makeSyntheticsCanaryHttpBinding = <
  I extends { Name: string },
  A,
  E,
  R,
>(options: {
  /** Fully-qualified binding tag, e.g. `AWS.Synthetics.GetCanaryRuns`. */
  tag: string;
  /** The distilled operation; `Name` is injected from the resource. */
  operation: Effect.Effect<(input: I) => Effect.Effect<A, E>, never, R>;
  /** IAM actions granted on the canary ARN. */
  actions: readonly string[];
}) =>
  Effect.gen(function* () {
    const op = yield* options.operation;

    return Effect.fn(function* (canary: Canary) {
      const Name = yield* canary.canaryName;
      if (!globalThis.__ALCHEMY_RUNTIME__) {
        const host = yield* Binding.Host;
        if (isBindingHost(host)) {
          yield* host.bind`Allow(${host}, ${options.tag}(${canary}))`({
            policyStatements: [
              {
                Effect: "Allow",
                Action: [...options.actions],
                Resource: [canary.canaryArn],
              },
            ],
          });
        }
      }
      return Effect.fn(`${options.tag}(${canary.LogicalId})`)(function* (
        request?: Omit<I, "Name">,
      ) {
        return yield* op({ ...request, Name: yield* Name } as I);
      });
    });
  });

/**
 * Build the impl Effect for an account-level Synthetics operation. The
 * runtime callable passes the caller's request through unchanged; the
 * deploy-time half grants `actions` on `*` (account-level reads such as
 * `DescribeCanariesLastRun` are not resource-addressable).
 */
export const makeSyntheticsAccountHttpBinding = <I, A, E, R>(options: {
  /** Fully-qualified binding tag, e.g. `AWS.Synthetics.DescribeCanariesLastRun`. */
  tag: string;
  /** The distilled operation, invoked with the caller's request as-is. */
  operation: Effect.Effect<(input: I) => Effect.Effect<A, E>, never, R>;
  /** IAM actions granted on `*`. */
  actions: readonly string[];
}) =>
  Effect.gen(function* () {
    const op = yield* options.operation;

    return Effect.fn(function* () {
      if (!globalThis.__ALCHEMY_RUNTIME__) {
        const host = yield* Binding.Host;
        if (isBindingHost(host)) {
          yield* host.bind`Allow(${host}, ${options.tag}())`({
            policyStatements: [
              {
                Effect: "Allow",
                Action: [...options.actions],
                Resource: ["*"],
              },
            ],
          });
        }
      }
      return Effect.fn(options.tag)(function* (request?: I) {
        return yield* op((request ?? {}) as I);
      });
    });
  });