import { DyNTS_SingletonServiceBase } from '../../_services/base/singleton.service-base';
import { DyNTS_global_settings } from '../../_collections/global-settings.const';

/**
 * In-memory ring buffer a szerver logokhoz.
 * Interceptalja a console.log/error/warn kimeneteket es tarolja oket.
 * Max entryszam a log_settings.logs_endpoint.maxEntries-bol jon (default: 2000).
 *
 * Hasznalat:
 *   DyNTS_Logs_Service.getInstance().install()  — egyszer, szerver indulasakor
 *   DyNTS_Logs_Service.getInstance().getLines(200)  — utolso N sor
 */
export class DyNTS_Logs_Service extends DyNTS_SingletonServiceBase {

  static getInstance(): DyNTS_Logs_Service {
    return DyNTS_Logs_Service.getSingletonInstance() as DyNTS_Logs_Service;
  }

  private readonly maxEntries: number;
  private readonly buffer: string[] = [];
  private installed: boolean = false;

  protected constructor() {
    super();
    this.maxEntries = DyNTS_global_settings.log_settings?.logs_endpoint?.maxEntries ?? 2000;
  }

  /**
   * Interceptalja a console.log/error/warn kimeneteket es a bufferbe irja.
   * Egyszer kell hivni, a szerver indulasakor. Tobbszori hivas no-op.
   */
  install(): void {
    if (this.installed) { return; }
    this.installed = true;

    const originalLog: typeof console.log = console.log.bind(console);
    const originalError: typeof console.error = console.error.bind(console);
    const originalWarn: typeof console.warn = console.warn.bind(console);

    const self: DyNTS_Logs_Service = this;

    console.log = (...args: any[]): void => {
      self.addLine('LOG', args);
      originalLog(...args);
    };

    console.error = (...args: any[]): void => {
      self.addLine('ERR', args);
      originalError(...args);
    };

    console.warn = (...args: any[]): void => {
      self.addLine('WRN', args);
      originalWarn(...args);
    };
  }

  /**
   * Az utolso N sor lekerdezese.
   */
  getLines(count: number = 200): string[] {
    const start: number = Math.max(0, this.buffer.length - count);
    return this.buffer.slice(start);
  }

  /**
   * Osszes bufferelt sor szama.
   */
  getLineCount(): number {
    return this.buffer.length;
  }

  /**
   * Buffer uritese.
   */
  clear(): void {
    this.buffer.length = 0;
  }

  /**
   * Telepitve van-e mar a console intercept.
   */
  isInstalled(): boolean {
    return this.installed;
  }

  private addLine(level: string, args: any[]): void {
    const message: string = args.map((arg: any) => {
      if (typeof arg === 'string') { return arg; }
      try { return JSON.stringify(arg); } catch { return String(arg); }
    }).join(' ');

    const timestamped: string = `${new Date().toISOString()} [${level}] ${message}`;
    this.buffer.push(timestamped);

    if (this.buffer.length > this.maxEntries) {
      this.buffer.shift();
    }
  }
}