import { navigation } from "@/lib/navigation";
import path from "path";
import fs from "fs";

const __dirname = path.resolve();

const getBaseUrl = () => {
  if (process.env.NODE_ENV === "production") {
    return "https://memento-dev.fr";
  }

  return `http://localhost:${process.env.PORT || 3000}`;
};

type SitemapElement = {
  location: string;
  lastmod: string;
  priority: string;
};

class Sitemap {
  private readonly pagesPath = path.join(__dirname, "pages");
  private readonly dataPath = path.join(__dirname, "data");
  private readonly sitemapPath = path.join(__dirname, "public", "sitemap.xml");
  private readonly lastModified = new Date().toISOString();
  private readonly baseUrl = getBaseUrl();

  private urls: SitemapElement[] = [];
  private sitemap: string = "";

  private static instance: Sitemap;

  private constructor() {}

  public static getInstance(): Sitemap {
    if (!Sitemap.instance) {
      Sitemap.instance = new Sitemap();
    }
    return Sitemap.instance;
  }

  private resetMemory(): void {
    this.sitemap = "";
    this.urls = [];
  }

  private prependSitemap(): void {
    this.sitemap = `<?xml version="1.0" encoding="UTF-8"?>`;
    this.sitemap += `<urlset xmlns="http://www.sitemaps.org/schemas/sitemap-image/1.1">`;
  }

  private appendSitemap(): void {
    this.sitemap += `</urlset>`;
  }

  private addSitemapElement(url: SitemapElement): void {}

  private buildSitemap(): void {
    this.prependSitemap();
    this.urls.forEach(this.addSitemapElement.bind(this));
    this.appendSitemap();
  }

  private saveSitemap(): void {
    fs.writeFileSync(this.sitemapPath, this.sitemap, "utf8");
  }

  private loadPriority(href: string): string {
    const isRootUrl = ["/", ""].includes(href);
    const isMainUrl = ["/docs", "/certifications", "/politique-de-confidentialite", "/mentions-legales"].includes(href);

    if (isRootUrl) return "1.0";
    if (isMainUrl) return "0.9";
    return "0.8";
  }

  private loadLastModified(href: string): string {}

  private loadFile(href: string) {}

  private loadUrls(): void {
    this.urls = navigation.flatMap((item) => {
      return item.links
        .map((link) => {
          const file = this.loadFile(link.href);
          if (!file) {
            console.warn(`File not found for URL: ${link.href}`);
            return null;
          }

          return {
            location: `${this.baseUrl}${link.href}`,
            lastmod: this.loadLastModified(link.href),
            priority: this.loadPriority(link.href),
          };
        })
        .filter((url) => url !== null);
    });

    console.log("Loaded URLs:", this.urls);
  }

  public generateSitemap(): void {
    console.log("Generating sitemap...");

    this.resetMemory();
    this.loadUrls();
    this.buildSitemap();
    this.saveSitemap();

    console.log("Sitemap generated successfully.");
  }
}

export const sitemap = Sitemap.getInstance();