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

/**
 * Shared scaffolding for AWS CloudFormation 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, the IAM action list, and
 * (for stack-scoped operations) the injected `StackName` is boilerplate.
 */

/**
 * Build the impl Effect for a stack-scoped operation: the runtime callable
 * injects the bound {@link Stack}'s stack id (the stack ARN, which every
 * CloudFormation API accepts as `StackName`) and the deploy-time half grants
 * `actions` on the stack ARN.
 */
export const makeCloudFormationStackHttpBinding = <
  I extends { StackName?: string },
  A,
  E,
  R,
>(options: {
  /** Fully-qualified binding tag, e.g. `AWS.CloudFormation.DescribeStacks`. */
  tag: string;
  /** The distilled operation; `StackName` is injected from the stack. */
  operation: Effect.Effect<(input: I) => Effect.Effect<A, E>, never, R>;
  /** IAM actions granted on the stack ARN. */
  actions: readonly string[];
}) =>
  Effect.gen(function* () {
    const op = yield* options.operation;

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

/**
 * Build the impl Effect for an account-level operation (cross-stack export
 * discovery, drift-detection polling, template validation). The deploy-time
 * half grants `actions` on `*` — these CloudFormation actions are not
 * resource-scoped.
 */
export const makeCloudFormationAccountHttpBinding = <I, A, E, R>(options: {
  /** Fully-qualified binding tag, e.g. `AWS.CloudFormation.ListExports`. */
  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);
      });
    });
  });