import { writeFileSync } from 'fs';
import { join } from 'path';
import { ensureFolderExists } from './file-utils';
import { Image } from './image-utils';

export default class Diagnostics {
  private store: Array<{ time: Date, message: string, image: Image, additionalMessage: string }>;

  private enabled: boolean;

  private prefixes: Array<string>;

  constructor(enabled: boolean) {
    this.enabled = enabled;
    if (this.enabled) {
      this.prefixes = [];
      this.store = new Array<{ time: Date, message: string, image: Image, additionalMessage: string }>();
    }
  }

  pushPrefix(value: string): void {
    if (!this.enabled) { return; }
    this.prefixes.push(value);
  }

  popPrefix(): boolean {
    if (!this.enabled) { return false; }
    return !!this.prefixes.length && !!this.prefixes.pop();
  }

  private preformatMessage(message: string): string {
    return this.prefixes.join() + message;
  }

  log(value: string, data?: Image | unknown): void {
    if (!this.enabled) { return; }

    const { image, additionalMessage } = data instanceof Image
      ? { image: data.clone(), additionalMessage: undefined }
      : { image: undefined, additionalMessage: JSON.stringify(data, null, 2) };

    this.store.push({
      time: new Date(),
      message: this.preformatMessage(value),
      image,
      additionalMessage,
    });
  }

  save(basePath: string, relative: string): void {
    if (!this.enabled) { return; }

    if (relative.endsWith('.png')) { relative = relative.slice(0, -4); }
    const folderName = join(basePath, relative);
    ensureFolderExists(folderName);
    this.store
      .filter((x) => x.image)
      .forEach((x) => {
        const fileName = this.getImageFileName(x);
        writeFileSync(join(folderName, fileName), x.image.getBuffer());
      });
    const logString = this.store.map((x) => {
      let result = `[${x.time}] ${x.message} `;
      if (x.image) {
        result += `>> ${this.getImageFileName(x)}`;
      }
      if (x.additionalMessage) {
        result += `:\r\n${x.additionalMessage}`;
      }
      return result;
    }).join('\r\n');

    writeFileSync(join(folderName, 'log.txt'), logString);
  }

  private getImageFileName(x: { message: string; image: Image; }) {
    let fileName = x.message;
    // https://docs.microsoft.com/en-us/windows/win32/api/shlobj_core/nf-shlobj_core-pathcleanupspec#remarks
    fileName = fileName.replace(/[\\/:*?"<>|\s]/g, '_');
    if (!fileName.endsWith('.png')) { fileName += '.png'; }
    return fileName;
  }
}