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

/**
 * Shared scaffolding for Amazon MemoryDB 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 builders
 * below. Everything except the operation, the identifier resolver, and the
 * IAM action list is boilerplate. The env-only side of `ConnectHttp` stays
 * bespoke — it attaches environment variables in addition to IAM policy.
 */

/**
 * MemoryDB snapshot ARNs embed the snapshot name, which is runtime data for
 * every snapshot-addressed operation, so snapshot-scoped grants use this
 * wildcard.
 */
export const SNAPSHOT_ARN_WILDCARD = "arn:aws:memorydb:*:*:snapshot/*";

/**
 * Build the impl Effect for an account-level operation (snapshot management,
 * cluster/event monitoring). The deploy-time half grants `actions` on
 * `resources` (default `*`) — these operations address clusters and
 * snapshots by names that are runtime data.
 */
export const makeMemoryDBAccountHttpBinding = <I, A, E, R>(options: {
  /** Fully-qualified binding tag, e.g. `AWS.MemoryDB.DescribeEvents`. */
  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. */
  actions: readonly string[];
  /**
   * IAM resources the actions are granted on.
   * @default ["*"]
   */
  resources?: 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: [...(options.resources ?? ["*"])],
              },
            ],
          });
        }
      }
      return Effect.fn(options.tag)(function* (request?: I) {
        return yield* op((request ?? {}) as I);
      });
    });
  });

/**
 * Build the impl Effect for a cluster-scoped operation: the runtime callable
 * injects the bound {@link Cluster}'s name as `ClusterName` and the
 * deploy-time half grants `actions` on the cluster ARN (plus any
 * `extraResources`, e.g. the snapshot ARN wildcard for snapshot creation).
 */
export const makeMemoryDBClusterHttpBinding = <
  I extends { ClusterName: string },
  A,
  E,
  R,
>(options: {
  /** Fully-qualified binding tag, e.g. `AWS.MemoryDB.FailoverShard`. */
  tag: string;
  /** The distilled operation; `ClusterName` is injected from the cluster. */
  operation: Effect.Effect<(input: I) => Effect.Effect<A, E>, never, R>;
  /** IAM actions granted on the cluster ARN. */
  actions: readonly string[];
  /** Static IAM resources granted in addition to the cluster ARN. */
  extraResources?: readonly string[];
}) =>
  Effect.gen(function* () {
    const op = yield* options.operation;

    return Effect.fn(function* (cluster: Cluster) {
      const ClusterName = yield* cluster.clusterName;
      if (!globalThis.__ALCHEMY_RUNTIME__) {
        const host = yield* Binding.Host;
        if (isBindingHost(host)) {
          yield* host.bind`Allow(${host}, ${options.tag}(${cluster}))`({
            policyStatements: [
              {
                Effect: "Allow",
                Action: [...options.actions],
                Resource: [
                  Output.interpolate`${cluster.clusterArn}`,
                  ...(options.extraResources ?? []),
                ],
              },
            ],
          });
        }
      }
      return Effect.fn(`${options.tag}(${cluster.LogicalId})`)(function* (
        request?: Omit<I, "ClusterName">,
      ) {
        return yield* op({
          ...request,
          ClusterName: yield* ClusterName,
        } as I);
      });
    });
  });