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

/**
 * Shared scaffolding for AWS Lambda control/data-plane HTTP bindings.
 *
 * NOT exported from `index.ts` — every near-identical `{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 IAM action list,
 * and the granted ARNs is boilerplate. Genuinely-different bindings (the
 * MicroVM family with its cross-cloud credential scaffolding in
 * `MicrovmBinding.ts`) stay bespoke.
 */

/**
 * Build the impl Effect for a function-scoped operation (`Invoke`,
 * `GetFunction`, `InvokeWithResponseStream`): the runtime callable injects
 * the bound {@link Function}'s ARN as `FunctionName` and the deploy-time
 * half grants `actions` on `resources` (default: the function ARN).
 */
export const makeFunctionHttpBinding = <
  I extends { FunctionName?: string },
  A,
  E,
  R,
>(options: {
  /** Fully-qualified binding tag, e.g. `AWS.Lambda.GetFunction`. */
  tag: string;
  /** The distilled operation; `FunctionName` is injected from the function. */
  operation: Effect.Effect<(input: I) => Effect.Effect<A, E>, never, R>;
  /** IAM actions granted on `resources`. */
  actions: readonly string[];
  /** ARNs the actions are granted on. @default the function ARN */
  resources?: (func: Function) => (string | OutputType<string>)[];
}) =>
  Effect.gen(function* () {
    const op = yield* options.operation;

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

/**
 * Build the impl Effect for an account-level operation
 * (`GetAccountSettings`, `ListFunctions`): the runtime callable passes the
 * caller's request through unchanged and the deploy-time half grants
 * `actions` on `*` (these Lambda actions do not support resource-level
 * permissions).
 */
export const makeLambdaAccountHttpBinding = <I, A, E, R>(options: {
  /** Fully-qualified binding tag, e.g. `AWS.Lambda.ListFunctions`. */
  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);
      });
    });
  });