/* v8 ignore start */
// Runtime utilities for sending emails using SMTP with Effect
// SMTP implementation is already tested in @withstudiocms/effect
// We import and create a custom SMTPMailer service here for StudioCMS specific use cases
import { db, eq } from 'astro:db';
import {
	type Mail,
	SMTPService,
	type SMTPTransport,
	SMTPTransportConfig,
	TransportConfig,
} from '@withstudiocms/effect/smtp';
import { CMSMailerConfigId } from '../../consts.js';
import { tsMailerConfig } from '../../db/config.js';
import { Effect, genLogger, Layer, pipeLogger } from '../../effect.js';

export type { Mail, SMTPTransport };

/**
 * Converts a null value to undefined.
 *
 * @param value - The value to convert.
 * @returns The value if it is not null, otherwise undefined.
 */
function nullToUndefined<T>(value: T | null): T | undefined {
	return value === null ? undefined : value;
}

/**
 * TypeSafe Table definition for use in StudioCMS Integrations
 */
export type tsMailer = typeof tsMailerConfig.$inferSelect;

/**
 * TypeSafe Table definition for use in StudioCMS Integrations
 */
export type tsMailerInsert = Omit<typeof tsMailerConfig.$inferInsert, 'id'>;

/**
 * Converts a mailer configuration object into a TransportConfig object.
 *
 * This function extracts the necessary fields from the mailer configuration
 * and constructs a TransportConfig object that can be used by the SMTP service.
 *
 * @param config - The mailer configuration object to convert.
 * @returns An Effect that resolves to a TransportConfig object.
 */
const convertTransporterConfig = (config: tsMailer) =>
	pipeLogger('studiocms/lib/effects/smtp/convertTransporterConfig')(
		Effect.try(() => {
			// Extract the required fields from the configuration object
			const {
				host,
				port,
				secure,
				proxy,
				auth_user,
				auth_pass,
				tls_rejectUnauthorized,
				tls_servername,
				default_sender,
			} = config;

			// Return the transporter configuration object
			return TransportConfig({
				transport: {
					host,
					port,
					secure,
					proxy: nullToUndefined(proxy),
					auth:
						auth_user !== null || auth_pass !== null
							? {
									user: nullToUndefined(auth_user),
									pass: nullToUndefined(auth_pass),
								}
							: undefined,
					tls:
						tls_rejectUnauthorized !== null || tls_servername !== null
							? {
									rejectUnauthorized: nullToUndefined(tls_rejectUnauthorized),
									servername: nullToUndefined(tls_servername),
								}
							: undefined,
				},
				defaults: {
					from: nullToUndefined(default_sender),
				},
			});
		})
	);

/**
 * Builds the SMTP transporter configuration from the database.
 * This function retrieves the mailer configuration from the database
 * and converts it into a TransportConfig object.
 * @returns An Effect that resolves to a TransportConfig object.
 * If the configuration is not found, it returns an empty TransportConfig.
 */
const buildTransporterConfig = genLogger('studiocms/lib/effects/smtp/buildTransporterConfig')(
	function* () {
		const configTable = yield* Effect.tryPromise(() =>
			db.select().from(tsMailerConfig).where(eq(tsMailerConfig.id, CMSMailerConfigId)).get()
		);

		// If the mailer configuration is not found, return an Empty config
		if (!configTable) {
			return TransportConfig({
				transport: {},
				defaults: {},
			});
		}

		return yield* convertTransporterConfig(configTable);
	}
);

/**
 * Represents the return type for the SMTPMailer service.
 */
export type SMTPMailerReturn = {
	getVersionString: () => Effect.Effect<string, Error, never>;
	isIdle: () => Effect.Effect<boolean, Error, never>;
	sendMail: (
		mailOptions: Mail.Options
	) => Effect.Effect<SMTPTransport.SentMessageInfo, Error, never>;
	verifyTransport: () => Effect.Effect<true, Error, never>;
};

/**
 * Builds a Layer that provides the SMTPTransportConfig for the given TransportConfig.
 * @param config - The TransportConfig to use for the SMTPTransportConfig.
 * @returns The Layer that provides the SMTPTransportConfig.
 */
const buildProvide = (config: TransportConfig) =>
	Effect.provide(Layer.provide(SMTPService.Default, SMTPTransportConfig.makeLive(config)));

/**
 * SMTPMailer service for sending emails.
 *
 * This service provides methods to send emails using the SMTP protocol.
 * It uses the configuration provided by the SMTPTransportConfig context.
 *
 * @extends Effect.Service
 * @template {SMTPMailer} - The type of the service.
 */
export class SMTPMailer extends Effect.Service<SMTPMailer>()(
	'studiocms/lib/effects/smtp/SMTPMailer',
	{
		effect: genLogger('studiocms/lib/effects/smtp/SMTPMailer.effect')(function* () {
			const config = yield* buildTransporterConfig;

			const { getVersionString, isIdle, sendMail, verifyTransport }: SMTPMailerReturn =
				yield* SMTPService.pipe(buildProvide(config));

			return { verifyTransport, sendMail, isIdle, getVersionString };
		}),
	}
) {}

/* v8 ignore stop */