import { EventEmitter } from "events";
import * as vscode from 'vscode';
import { WebviewPanel } from "vscode";

export class Hanlder {

    constructor(public panel: WebviewPanel, private eventEmitter: EventEmitter) { }

    on(event: string, callback: (content: any) => void): this {
        this.eventEmitter.on(event, callback)
        return this;
    }

    emit(event: string, content?: any) {
        this.panel.webview.postMessage({ type: event, content })
    }

    public static bind(panel: WebviewPanel,uri:vscode.Uri): Hanlder {
        const eventEmitter = new EventEmitter();

        const fileWatcher = vscode.workspace.createFileSystemWatcher(uri.fsPath)
        fileWatcher.onDidChange(e=>{
            eventEmitter.emit("fileChange", e)
        })

        const changeDocumentSubscription = vscode.workspace.onDidChangeTextDocument(e => {
            if (e.document.uri.toString() === uri.toString()) {
                eventEmitter.emit("externalUpdate", e)
            }
        });
        panel.onDidDispose(() => {
            changeDocumentSubscription.dispose()
            eventEmitter.emit("dispose")
        });

        // bind from webview
        panel.webview.onDidReceiveMessage((message) => {
            eventEmitter.emit(message.type, message.content)
        })
        return new Hanlder(panel, eventEmitter);
    }

}