import * as RTE from "fp-ts/ReaderTaskEither";
import * as O from "fp-ts/Option";
import { pipe } from "fp-ts/function";

import { isPrismicWebhookBodyApiUpdate } from "./lib/isPrismicWebhookBodyApiUpdate";
import { isPrismicWebhookBodyForRepository } from "./lib/isPrismicWebhookBodyForRepository";
import { isPrismicWebhookBodyTestTrigger } from "./lib/isPrismicWebhookBodyTestTrigger";
import { isValidWebhookSecret } from "./lib/isValidWebhookSecret";
import { reportWarning } from "./lib/reportWarning";

import { Dependencies, PrismicWebhookBody } from "./types";
import { WEBHOOK_SECRET_MISMATCH_MSG } from "./constants";
import { onWebhookApiUpdate } from "./on-webhook-api-update";
import { onWebhookTestTrigger } from "./on-webhook-test-trigger";

/**
 * Calls the appropriate webhook handler depending on its contents.
 *
 * If the webhook is not intended for this plugin, the webhook is ignored.
 */
const onPrismicWebhook = (
	webhookBody: PrismicWebhookBody,
): RTE.ReaderTaskEither<Dependencies, Error, void> =>
	pipe(
		RTE.ask<Dependencies>(),
		RTE.chain((deps) =>
			pipe(
				webhookBody,
				O.fromPredicate(isValidWebhookSecret(deps.pluginOptions.webhookSecret)),
				O.fold(
					() => reportWarning(WEBHOOK_SECRET_MISMATCH_MSG),
					(webhookBody) => {
						if (isPrismicWebhookBodyApiUpdate(webhookBody)) {
							return onWebhookApiUpdate(webhookBody);
						}

						if (isPrismicWebhookBodyTestTrigger(webhookBody)) {
							return onWebhookTestTrigger;
						}

						// This webhook is unsupported or does not pertain to this plugin.
						return RTE.right(void 0);
					},
				),
			),
		),
	);

/**
 * To be executed in the `sourceNodes` stage when a webhook is received.
 *
 * If the webhook is from Prismic, and the webhook's secret matches the secret
 * defined in the environment's plugin options, a handler appropriate to the
 * webhook's type is called.
 *
 * All nodes, regardless of the webhook' source or contents, are touched to
 * prevent garbage collection.
 */
export const onWebhook: RTE.ReaderTaskEither<Dependencies, Error, void> = pipe(
	RTE.ask<Dependencies>(),
	RTE.chain((deps) =>
		pipe(
			deps.webhookBody,
			O.fromPredicate(
				isPrismicWebhookBodyForRepository(deps.pluginOptions.repositoryName),
			),
			O.fold(() => RTE.right(void 0), onPrismicWebhook),
		),
	),
);