import { FlinkContext, FlinkRequest, RouteProps, HttpMethod } from "@flink-app/flink";

/**
 * Streaming format types
 */
export type StreamFormat = "sse" | "ndjson";

/**
 * Stream writer interface for sending data to clients
 */
export interface StreamWriter<T = any> {
    /**
     * Write data to the stream
     */
    write(data: T): void;

    /**
     * Send an error event to the stream
     */
    error(error: Error | string): void;

    /**
     * End the stream
     */
    end(): void;

    /**
     * Check if the connection is still open
     */
    isOpen(): boolean;
}

/**
 * Props passed to streaming handlers
 */
export interface StreamHandlerProps<Ctx extends FlinkContext, T = any> {
    req: FlinkRequest;
    ctx: Ctx;
    stream: StreamWriter<T>;
    origin?: string;
}

/**
 * Streaming handler function signature
 */
export type StreamHandler<Ctx extends FlinkContext, T = any> = (
    props: StreamHandlerProps<Ctx, T>
) => Promise<void> | void;

/**
 * Route configuration for streaming endpoints
 */
export interface StreamingRouteProps extends Omit<RouteProps, "skipAutoRegister"> {
    /**
     * HTTP path for the streaming endpoint
     */
    path: string;

    /**
     * HTTP method (defaults to GET)
     */
    method?: HttpMethod;

    /**
     * Streaming format to use
     * - 'sse': Server-Sent Events (text/event-stream)
     * - 'ndjson': Newline-Delimited JSON (application/x-ndjson)
     * @default 'sse'
     */
    format?: StreamFormat;

    /**
     * Must be true for streaming handlers (prevents auto-registration)
     */
    skipAutoRegister: true;
}

/**
 * Options for creating the streaming plugin
 */
export interface StreamingPluginOptions {
    /**
     * Default format if not specified in route props
     * @default 'sse'
     */
    defaultFormat?: StreamFormat;

    /**
     * Enable debug logging
     * @default false
     */
    debug?: boolean;
}

/**
 * Handler module type (namespace import with default export and Route)
 */
export interface StreamHandlerModule<Ctx extends FlinkContext = any, T = any> {
    default: StreamHandler<Ctx, T>;
    Route: StreamingRouteProps;
}