import type {LoggingLevel, LoggingLevelType} from '../LoggingLevel';
import type {IAppender} from './IAppender';
import type ILogMessage from './LogMessage';

export default class TechnikerMeAppender implements IAppender {
  private readonly _logRecorderUrl: string = 'https://logserver.techniker.me/api/logs';
  // @ts-ignore
  private readonly _domain: string = typeof globalThis !== 'undefined' ? (globalThis.location?.hostname ?? '') : '';
  private readonly _logMessageQueue: ILogMessage[] = [];
  private _pendingPostLogMessagePromise: Promise<Response | undefined> | undefined = undefined;

  public log(timestamp: string, level: LoggingLevelType, category: string, message: string): void {
    const logMessage = {
      timestamp,
      domain: this._domain,
      level,
      category,
      message
    };
    this.queueMessage(logMessage);
    this.postLogMessage();
  }

  private async postLogMessage(): Promise<void> {
    const logMessage = this._logMessageQueue.shift();

    if (!logMessage || this._pendingPostLogMessagePromise !== undefined) {
      return;
    }

    try {
      if (typeof fetch === 'undefined') {
        console.error('Fetch API is not available in this environment');
        return;
      }

      this._pendingPostLogMessagePromise = fetch(this._logRecorderUrl, {
        headers: {
          'Content-Type': 'application/json',
          Accept: 'application/json'
        },
        mode: 'no-cors',
        method: 'POST',
        body: JSON.stringify(logMessage)
      }).then(() => (this._pendingPostLogMessagePromise = undefined));
    } catch (e) {
      console.error('Unable to send logs due to [%o]', e);
      return;
    }
  }

  private queueMessage(logMessage: ILogMessage): void {
    this._logMessageQueue.push(logMessage);
  }
}