import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root',
})
export class SharedService {
  isBtnDisabled: boolean = false;
  isAnyDialogOpen: boolean = false;
  isMobileNavbarOpen: boolean = false;
  isNewContactDialogOpen: boolean = false;
  isEditContactDialogOpen: boolean = false;
  isDeleteContactDialogOpen: boolean = false;
  isPageViewMedia: boolean = window.innerWidth <= 650;
  isContactViewMedia: boolean = window.innerWidth <= 800;
  currentUserId: string = '';

  private resizeListener!: () => void;

  constructor() {
    this.initResizeListener();
  }

  // CHECK VIEW WIDTH

  /**
   * Initializes the window resize listener.
   *
   * @remarks
   * This function will set up the window resize listener and bind the
   * onResize() method to it.
   */
  private initResizeListener() {
    this.resizeListener = this.onResize.bind(this);
    window.addEventListener('resize', this.resizeListener);
  }

  /**
   * Removes the window resize listener.
   *
   * @remarks
   * This function will remove the window resize listener that was set up in
   * the constructor. This is useful when the service is being destroyed.
   */
  private removeResizeListener() {
    window.removeEventListener('resize', this.resizeListener);
  }

  /**
   * Window resize event listener method.
   *
   * @remarks
   * This method will update the isPageViewMedia and isContactViewMedia
   * properties based on the current window width whenever the window is
   * resized.
   */
  private onResize() {
    this.isPageViewMedia = window.innerWidth <= 650;
    this.isContactViewMedia = window.innerWidth <= 800;
  }

  /**
   * Cleans up the service by removing the window resize listener.
   *
   * @remarks
   * This function is useful when the service is being destroyed.
   */
  cleanup() {
    this.removeResizeListener();
  }

  // RANDOM COLOR

  /**
   * Generates a random color string.
   *
   * @remarks
   * The generated color is a hex string that is not a shade of gray.
   * The color is generated by randomly selecting a hex digit from the
   * string '0123456789ABCDEF' and appending it to the color string. The
   * loop continues until a non-gray color is generated.
   *
   * @returns A random color string.
   */
  generateRandomColor(): string {
    const letters = '0123456789ABCDEF';
    let color = '#';
    let isGrayScale = true;

    while (isGrayScale) {
      for (let i = 0; i < 6; i++) {
        color += letters[Math.floor(Math.random() * 16)];
      }
      const rgb = this.hexToRgb(color);
      if (rgb.r !== rgb.g || rgb.g !== rgb.b) {
        isGrayScale = false;
      } else {
        color = '#';
      }
    }

    return color;
  }

  /**
   * Converts a hex color string to an RGB object.
   *
   * @param hex A color string in hex format, e.g. '#FF0000'.
   * @returns An object with r, g, and b properties, each an integer between
   * 0 and 255, representing the red, green, and blue components of the color.
   */
  hexToRgb(hex: string): { r: number; g: number; b: number } {
    const bigint = parseInt(hex.substring(1), 16);
    const r = (bigint >> 16) & 255;
    const g = (bigint >> 8) & 255;
    const b = bigint & 255;
    return { r, g, b };
  }

  // SECURITY

  /**
   * Sanitizes the input string by replacing any potential cross-site scripting characters.
   * This ensures that the input string is safe to be stored in the Firebase Realtime Database.
   * @param input The input string to be sanitized.
   * @returns The sanitized string.
   */
  replaceXSSChars(input: string) {
    return input.replace(/</g, '&lt;').replace(/>/g, '&gt;');
  }
}