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 { Server } from "./Server.ts";
import type { User } from "./User.ts";

/**
 * Shared scaffolding for the AWS Transfer Family runtime bindings.
 *
 * NOT exported from `index.ts` — every `{Op}Http.ts` in this service is a
 * thin `Layer.effect(Cap, makeTransfer…HttpBinding({ … }))` over one of the
 * three builders below. Everything except the operation, the IAM action
 * list, and the injected identifier(s) is boilerplate.
 */

/**
 * Build the impl Effect for a server-scoped Transfer operation: the runtime
 * callable injects the bound {@link Server}'s ID as `ServerId` and the
 * deploy-time half grants `actions` on the server's ARN.
 */
export const makeTransferServerHttpBinding = <
  I extends { ServerId?: string },
  A,
  E,
  R,
>(options: {
  /** Fully-qualified binding tag, e.g. `AWS.Transfer.StartServer`. */
  tag: string;
  /** The distilled operation; `ServerId` is injected from the server. */
  operation: Effect.Effect<(input: I) => Effect.Effect<A, E>, never, R>;
  /** IAM actions granted on the server ARN. */
  actions: readonly string[];
  /**
   * Override the IAM resource derived from the server. Most server-scoped
   * operations authorize against the server ARN; a few operations use a
   * related resource type instead (for example, TestIdentityProvider uses a
   * user ARN even though ServerId is the injected request identifier).
   */
  resource?: (server: Server) => string | Output.Output<string>;
}) =>
  Effect.gen(function* () {
    const op = yield* options.operation;

    return Effect.fn(function* (server: Server) {
      // Outputs yield a DEFERRED effect — resolve again per invocation below.
      const ServerId = yield* server.serverId;
      if (!globalThis.__ALCHEMY_RUNTIME__) {
        const host = yield* Binding.Host;
        if (isBindingHost(host)) {
          yield* host.bind`Allow(${host}, ${options.tag}(${server}))`({
            policyStatements: [
              {
                Effect: "Allow",
                Action: [...options.actions],
                Resource: [
                  options.resource?.(server) ??
                    Output.interpolate`${server.arn}`,
                ],
              },
            ],
          });
        }
      }
      return Effect.fn(`${options.tag}(${server.LogicalId})`)(function* (
        request?: Omit<I, "ServerId">,
      ) {
        return yield* op({ ...request, ServerId: yield* ServerId } as I);
      });
    });
  });

/**
 * Build the impl Effect for a user-scoped Transfer operation: the runtime
 * callable injects the bound {@link User}'s `ServerId` + `UserName` and the
 * deploy-time half grants `actions` on the user's ARN
 * (`arn:…:user/{serverId}/{userName}`).
 */
export const makeTransferUserHttpBinding = <
  I extends { ServerId?: string; UserName?: string },
  A,
  E,
  R,
>(options: {
  /** Fully-qualified binding tag, e.g. `AWS.Transfer.ImportSshPublicKey`. */
  tag: string;
  /** The distilled operation; `ServerId` + `UserName` are injected. */
  operation: Effect.Effect<(input: I) => Effect.Effect<A, E>, never, R>;
  /** IAM actions granted on the user ARN. */
  actions: readonly string[];
}) =>
  Effect.gen(function* () {
    const op = yield* options.operation;

    return Effect.fn(function* (user: User) {
      // Outputs yield a DEFERRED effect — resolve again per invocation below.
      const ServerId = yield* user.serverId;
      const UserName = yield* user.userName;
      if (!globalThis.__ALCHEMY_RUNTIME__) {
        const host = yield* Binding.Host;
        if (isBindingHost(host)) {
          yield* host.bind`Allow(${host}, ${options.tag}(${user}))`({
            policyStatements: [
              {
                Effect: "Allow",
                Action: [...options.actions],
                Resource: [Output.interpolate`${user.arn}`],
              },
            ],
          });
        }
      }
      return Effect.fn(`${options.tag}(${user.LogicalId})`)(function* (
        request?: Omit<I, "ServerId" | "UserName">,
      ) {
        return yield* op({
          ...request,
          ServerId: yield* ServerId,
          UserName: yield* UserName,
        } as I);
      });
    });
  });

/**
 * Build the impl Effect for an account-level Transfer operation (no
 * resource argument): the deploy-time half grants `actions` on `*`. Used
 * for operations that authorize against ARNs unknowable at deploy time
 * (e.g. `SendWorkflowStepState` authorizes on the workflow's own ARN, and
 * the workflow/execution ids arrive at runtime inside the step event).
 */
export const makeTransferAccountHttpBinding = <I, A, E, R>(options: {
  /** Fully-qualified binding tag, e.g. `AWS.Transfer.SendWorkflowStepState`. */
  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);
      });
    });
  });