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

/**
 * Shared HTTP scaffolding for the Comprehend Medical runtime bindings.
 *
 * Comprehend Medical is a pure pay-per-call service: none of its actions
 * support resource-level IAM, so every binding is account-level and grants
 * its action(s) on `Resource: ["*"]`. The only variation between bindings is
 * the distilled operation, the IAM action, and whether the operation passes
 * a data-access role to the service (the `Start*Job` operations, which
 * additionally need `iam:PassRole` scoped to
 * `comprehendmedical.amazonaws.com`).
 *
 * NOT exported from `index.ts` — every thin `{Op}Http.ts` in this service is
 * a `Layer.effect(Cap, makeComprehendMedicalHttpBinding({ … }))`.
 */
export const makeComprehendMedicalHttpBinding = <I, A, E, R>(options: {
  /**
   * Short capability name used in the binding sid and runtime span, e.g.
   * `"DetectEntitiesV2"`.
   */
  capability: string;
  /**
   * IAM actions granted on `Resource: ["*"]` (Comprehend Medical has no
   * resource-level IAM).
   */
  iamActions: readonly string[];
  /**
   * The distilled operation implementing the capability.
   */
  operation: Effect.Effect<(input: I) => Effect.Effect<A, E>, never, R>;
  /**
   * Grant `iam:PassRole` (conditioned to `comprehendmedical.amazonaws.com`)
   * so the function can hand the service the `DataAccessRoleArn` a batch job
   * assumes to read/write S3. Set on the `Start*Job` bindings.
   */
  passRole?: boolean;
}) =>
  Effect.gen(function* () {
    const op = yield* options.operation;

    return Effect.fn(function* () {
      if (!globalThis.__ALCHEMY_RUNTIME__) {
        const host = yield* Binding.Host;
        if (isBindingHost(host)) {
          const policyStatements: PolicyStatement[] = [
            {
              Effect: "Allow",
              Action: [...options.iamActions],
              // Comprehend Medical actions have no resource-level IAM.
              Resource: ["*"],
            },
          ];
          if (options.passRole) {
            policyStatements.push({
              Effect: "Allow",
              Action: ["iam:PassRole"],
              Resource: ["*"],
              Condition: {
                StringEquals: {
                  "iam:PassedToService": "comprehendmedical.amazonaws.com",
                },
              },
            });
          }
          yield* host.bind`Allow(${host}, AWS.ComprehendMedical.${options.capability}())`(
            { policyStatements },
          );
        }
      }
      return Effect.fn(`AWS.ComprehendMedical.${options.capability}`)(
        function* (request: I) {
          return yield* op(request);
        },
      );
    });
  });