export class RFAMessage {
    jsonrpc = "2.0";        // Transmits version of JSON-RPC. Compliance maybe allows some funky interaction with external tools?
    public method?:string; // Is defined when it's a request/notification, otherwise undefined
    public result?:string; // Is defined when it's a response, otherwise undefined
    public params?:FileMetadata; // Optional parameters to method
    public error? :string; // Only defined on error
    public id?    :number; // ID to keep track of request -> response interaction, undefined with notifications, defined with request/response

    constructor(obj: { method?: string; result?: string; params?: FileMetadata; error?: string; id?: number } = {}){
        this.method = obj.method;
        this.result = obj.result;
        this.params = obj.params;
        this.error  = obj.error;
        this.id     = obj.id;
    }
}

type FileMetadata = FileData
                    | FileContent
                    | FileLocation
                    | FileServer;

export interface FileData {
    filename: string;
    content: string;
    server: string;
}

export interface FileContent {
    filename: string;
    content: string;
}

export interface FileLocation {
    filename: string;
    server: string;
}

export interface FileServer {
    server: string;
}

export function isFileData(p: unknown): p is FileData {
    const pf = p as FileData
    return typeof pf.server === 'string' &&
        typeof pf.filename === 'string' &&
        typeof pf.content === 'string'
}

export function isFileLocation(p: unknown): p is FileLocation {
    const pf = p as FileLocation
    return typeof pf.server === 'string' &&
        typeof pf.filename === 'string'
}

export function isFileContent(p: unknown): p is FileContent {
    const pf = p as FileContent
    return typeof pf.filename === 'string' &&
        typeof pf.content === 'string'
}

export function isFileServer(p: unknown): p is FileServer {
    const pf = p as FileServer
    return typeof pf.server === 'string'
}