import type { ErrorPayload, HotPayload } from 'vite';

/** marks a response body as JSON-encoded {@link SerializedError} */
export const ERROR_HEADER = 'x-dromi-error';

/** request error in Vite's overlay format */
export type SerializedError = ErrorPayload['err'];

/** Vite hot channel payload, relayed in either direction */
export type HotMessage = { type: 'hot'; payload: HotPayload };

/** first message sent to the Deno process */
export type InitMessage = {
	type: 'init';
	/** absolute path to the server entrypoint */
	entry: string;
	/** URL of `vite/module-runner`, matching the `vite` that runs the dev server */
	moduleRunner: string;
};

/** Deno process log for Vite's logger */
export type LogMessage = {
	type: 'log';
	level: 'error' | 'info';
	message: string;
};

/** sent by the Deno process once its server is listening */
export type ReadyMessage = {
	type: 'ready';
	/** port of the server, on `127.0.0.1` */
	port: number;
};

/** requests a process restart for an unaccepted HMR update */
export type RestartMessage = { type: 'restart' };

/** worker module runner request to Vite's hot channel */
export type InvokeMessage = {
	type: 'invoke';
	/** request id, unique across workers */
	id: string;
	payload: HotPayload;
};

/** response to an {@link InvokeMessage}, with the same `id` */
export type ResultMessage = {
	type: 'result';
	id: string;
	result: { result: unknown } | { error: unknown };
};

/** message sent from the Vite host to the Deno process */
export type HostMessage = HotMessage | InitMessage | ResultMessage;

/** message sent from the Deno process to the Vite host */
export type RunnerMessage = HotMessage | InvokeMessage | LogMessage | ReadyMessage | RestartMessage;

/** `BroadcastChannel` shared by the Deno main thread and its workers */
export const WORKER_CHANNEL = 'dromi:worker';

/** worker requests and host responses relayed by the main thread over {@link WORKER_CHANNEL} */
export type WorkerChannelMessage = InvokeMessage | ResultMessage;