import path from "node:path";
import fs from "node:fs/promises";
import crypto from "node:crypto";
import { marked } from "marked";
import type { ToolHandler, ToolResult } from "./types";

const PDF_CSS = `
@page { margin: 2cm; }
body {
  font-family: -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
  line-height: 1.6;
  color: #222;
  font-size: 11pt;
}
h1 { color: #1a1a2e; border-bottom: 2px solid #1a1a2e; padding-bottom: 6px; }
h2 { color: #333; margin-top: 1.5em; }
h3 { color: #444; }
code {
  background: #f4f4f4;
  padding: 2px 6px;
  border-radius: 3px;
  font-family: ui-monospace, "JetBrains Mono", "Fira Code", monospace;
  font-size: 0.92em;
}
pre {
  background: #f4f4f4;
  padding: 1em;
  border-radius: 4px;
  overflow-x: auto;
  font-size: 0.88em;
  page-break-inside: avoid;
}
pre code { background: transparent; padding: 0; }
table { border-collapse: collapse; width: 100%; margin: 1em 0; }
td, th { border: 1px solid #ccc; padding: 8px; text-align: left; vertical-align: top; }
th { background: #f0f0f0; }
blockquote {
  border-left: 4px solid #ccc;
  margin-left: 0;
  padding-left: 1em;
  color: #555;
  font-style: italic;
}
a { color: #1a5dc7; text-decoration: none; }
img { max-width: 100%; height: auto; }
ul, ol { padding-left: 1.5em; }
hr { border: 0; border-top: 1px solid #ccc; margin: 1.5em 0; }
.meta {
  color: #888;
  font-size: 9pt;
  margin-bottom: 1.5em;
  border-bottom: 1px solid #eee;
  padding-bottom: 0.5em;
}
`;

function escapeHtml(s: string): string {
  return s
    .replace(/&/g, "&")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;")
    .replace(/"/g, "&quot;")
    .replace(/'/g, "&#39;");
}

function safeTitle(title: string): string {
  return (
    title
      .toLowerCase()
      .replace(/[^a-z0-9-]+/g, "-")
      .replace(/^-+|-+$/g, "")
      .slice(0, 50) || "document"
  );
}

export const PDF_STORAGE_DIR = path.join(process.cwd(), "data", "pdfs");

export const generatePdf: ToolHandler = async (args): Promise<ToolResult> => {
  const title = typeof args.titre === "string" ? args.titre.trim() : "";
  const md = typeof args.contenu_markdown === "string" ? args.contenu_markdown : "";
  if (!title) return { content: "Titre vide.", error: "empty_title" };
  if (!md.trim()) return { content: "Contenu markdown vide.", error: "empty_content" };

  marked.setOptions({ gfm: true, breaks: true });
  const bodyHtml = await marked.parse(md);
  const now = new Date();
  const dateLabel = now.toLocaleDateString("fr-FR", {
    year: "numeric",
    month: "long",
    day: "numeric",
  });

  const html = `<!DOCTYPE html><html lang="fr"><head>
<meta charset="utf-8">
<title>${escapeHtml(title)}</title>
<style>${PDF_CSS}</style>
</head><body>
<h1>${escapeHtml(title)}</h1>
<div class="meta">Généré le ${escapeHtml(dateLabel)}</div>
${bodyHtml}
</body></html>`;

  // Lazily require puppeteer so the rest of the app still boots if it's missing.
  let puppeteer: typeof import("puppeteer");
  try {
    puppeteer = (await import("puppeteer")).default ?? (await import("puppeteer"));
  } catch (e) {
    return {
      content: `puppeteer indisponible : ${e instanceof Error ? e.message : "import failed"}. Lance \`npm install\`.`,
      error: "puppeteer_missing",
    };
  }

  await fs.mkdir(PDF_STORAGE_DIR, { recursive: true });
  const filename = `${Date.now()}_${crypto.randomBytes(4).toString("hex")}_${safeTitle(title)}.pdf`;
  const filepath = path.join(PDF_STORAGE_DIR, filename);

  let browser: import("puppeteer").Browser | null = null;
  try {
    browser = await puppeteer.launch({
      headless: true,
      args: ["--no-sandbox", "--disable-setuid-sandbox"],
    });
    const page = await browser.newPage();
    await page.setContent(html, { waitUntil: "networkidle0", timeout: 20_000 });
    const pdfBuffer = await page.pdf({
      format: "A4",
      printBackground: true,
      margin: { top: "2cm", bottom: "2cm", left: "2cm", right: "2cm" },
    });
    await fs.writeFile(filepath, pdfBuffer);
  } catch (e) {
    return {
      content: `Erreur lors du rendu PDF : ${e instanceof Error ? e.message : "inconnue"}`,
      error: "render_error",
    };
  } finally {
    if (browser) await browser.close().catch(() => undefined);
  }

  const pdfUrl = `/api/pdfs/${encodeURIComponent(filename)}`;
  return {
    content: `PDF généré avec succès. URL : ${pdfUrl}`,
    meta: { pdfUrl, filename, title },
  };
};