"use client";

import { FileDownIcon } from "lucide-react";
import { useState, type RefObject } from "react";
import { toast } from "sonner";
import { cn } from "@/lib/utils";

type ResponsePdfDownloadButtonProps = {
  contentRef: RefObject<HTMLElement | null>;
  fileName?: string;
  siteLogo?: string | null;
  siteName?: string | null;
  title?: string;
};

function escapeHtml(value: string) {
  return value
    .replace(/&/g, "&amp;")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;")
    .replace(/"/g, "&quot;");
}

function getSafeTitle(value?: string | null) {
  return String(value || "").replace(/\s+/g, " ").trim();
}

function getSafeFileName(value?: string | null) {
  const normalized = getSafeTitle(value || "Claw 分析报告")
    .replace(/[\\/:*?"<>|]/g, "_")
    .slice(0, 80);
  return normalized || "Claw 分析报告";
}

function clonePrintableStyles(targetWindow: Window) {
  document
    .querySelectorAll<HTMLLinkElement | HTMLStyleElement>(
      'link[rel="stylesheet"], style'
    )
    .forEach((node) => {
      targetWindow.document.head.appendChild(node.cloneNode(true));
    });
}

function createPrintOverrides(targetWindow: Window) {
  const style = targetWindow.document.createElement("style");
  style.textContent = `
    :root {
      --background: #ffffff;
      --foreground: #111827;
      --border: #e5e7eb;
      --card: #ffffff;
      --muted: #f3f4f6;
      --muted-foreground: #6b7280;
      --primary: #111827;
    }

    html,
    body {
      margin: 0;
      background: #ffffff;
      color: #111827;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    }

    body {
      -webkit-print-color-adjust: exact;
      print-color-adjust: exact;
    }

    .claw-pdf-shell {
      box-sizing: border-box;
      width: 1120px;
      max-width: 100%;
      margin: 0 auto;
      padding: 32px;
      background: #ffffff;
    }

    .claw-pdf-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 24px;
      padding-bottom: 18px;
      margin-bottom: 24px;
      border-bottom: 1px solid #e5e7eb;
    }

    .claw-pdf-brand {
      display: flex;
      min-width: 0;
      align-items: center;
      gap: 12px;
    }

    .claw-pdf-logo,
    .claw-pdf-logo-fallback {
      width: 38px;
      height: 38px;
      flex: 0 0 auto;
      border-radius: 10px;
    }

    .claw-pdf-logo {
      object-fit: contain;
      background: #ffffff;
    }

    .claw-pdf-logo-fallback {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      background: #111827;
      color: #ffffff;
      font-size: 15px;
      font-weight: 700;
    }

    .claw-pdf-site {
      font-size: 18px;
      line-height: 1.2;
      font-weight: 700;
      color: #111827;
    }

    .claw-pdf-title {
      margin-top: 4px;
      font-size: 12px;
      line-height: 1.4;
      color: #6b7280;
    }

    .claw-pdf-time {
      flex: 0 0 auto;
      text-align: right;
      font-size: 11px;
      color: #6b7280;
    }

    .claw-pdf-content {
      font-size: 14px;
      line-height: 1.7;
    }

    [data-pdf-exclude="true"] {
      display: none !important;
    }

    .chat-card-x-scroll {
      overflow: visible !important;
      padding-bottom: 0 !important;
      scrollbar-width: none !important;
    }

    .chat-card-x-scroll::-webkit-scrollbar {
      display: none !important;
    }

    table {
      page-break-inside: auto;
    }

    tr,
    svg,
    img {
      page-break-inside: avoid;
    }

    svg {
      max-width: 100% !important;
      height: auto;
    }

    @page {
      size: A4 landscape;
      margin: 12mm;
    }

    @media print {
      .claw-pdf-shell {
        width: auto;
        max-width: none;
        padding: 0;
      }
    }
  `;
  targetWindow.document.head.appendChild(style);
}

export function ResponsePdfDownloadButton({
  contentRef,
  fileName,
  siteLogo,
  siteName,
  title = "Claw 分析报告",
}: ResponsePdfDownloadButtonProps) {
  const [isPreparing, setIsPreparing] = useState(false);
  const resolvedSiteName = getSafeTitle(siteName) || "AI Chatbot";
  const resolvedTitle = getSafeTitle(title) || "Claw 分析报告";

  const handleDownloadPdf = () => {
    const contentElement = contentRef.current;
    if (!contentElement) {
      toast.error("未找到可导出的内容");
      return;
    }

    const printWindow = window.open(
      "",
      "_blank",
      "width=1200,height=820"
    );
    if (!printWindow) {
      toast.error("浏览器阻止了 PDF 导出窗口，请允许弹窗后重试");
      return;
    }

    setIsPreparing(true);

    try {
      const safeDocumentTitle = getSafeFileName(fileName || resolvedTitle);
      printWindow.document.open();
      printWindow.document.write(
        `<!doctype html><html><head><meta charset="utf-8"><title>${escapeHtml(
          safeDocumentTitle
        )}</title><base href="${escapeHtml(window.location.origin)}"></head><body></body></html>`
      );
      printWindow.document.close();
      clonePrintableStyles(printWindow);
      createPrintOverrides(printWindow);

      const shell = printWindow.document.createElement("main");
      shell.className = "claw-pdf-shell";

      const header = printWindow.document.createElement("header");
      header.className = "claw-pdf-header";
      const brand = printWindow.document.createElement("div");
      brand.className = "claw-pdf-brand";
      if (siteLogo) {
        const logo = printWindow.document.createElement("img");
        logo.className = "claw-pdf-logo";
        logo.alt = resolvedSiteName;
        logo.src = siteLogo;
        brand.appendChild(logo);
      } else {
        const fallback = printWindow.document.createElement("span");
        fallback.className = "claw-pdf-logo-fallback";
        fallback.textContent = resolvedSiteName.slice(0, 1).toUpperCase();
        brand.appendChild(fallback);
      }

      const brandText = printWindow.document.createElement("div");
      brandText.innerHTML = `<div class="claw-pdf-site">${escapeHtml(
        resolvedSiteName
      )}</div><div class="claw-pdf-title">${escapeHtml(resolvedTitle)}</div>`;
      brand.appendChild(brandText);

      const time = printWindow.document.createElement("div");
      time.className = "claw-pdf-time";
      time.textContent = new Date().toLocaleString("zh-CN", {
        hour12: false,
      });

      header.appendChild(brand);
      header.appendChild(time);
      shell.appendChild(header);

      const content = printWindow.document.createElement("section");
      content.className = "claw-pdf-content";
      const clonedContent = contentElement.cloneNode(true) as HTMLElement;
      clonedContent
        .querySelectorAll('[data-pdf-exclude="true"]')
        .forEach((node) => node.remove());
      content.appendChild(clonedContent);
      shell.appendChild(content);
      printWindow.document.body.appendChild(shell);

      window.setTimeout(() => {
        setIsPreparing(false);
        printWindow.focus();
        printWindow.print();
      }, 600);
    } catch (error) {
      setIsPreparing(false);
      printWindow.close();
      console.error("[Response PDF] export failed:", error);
      toast.error("PDF 导出失败，请稍后重试");
    }
  };

  return (
    <button
      type="button"
      className={cn(
        "inline-flex h-8 items-center gap-1.5 rounded-md border border-border/70 bg-background/80 px-2.5 text-xs font-medium text-muted-foreground shadow-sm transition-colors hover:bg-muted hover:text-foreground",
        isPreparing && "pointer-events-none opacity-70"
      )}
      onClick={handleDownloadPdf}
      disabled={isPreparing}
      title="导出整段回复为 PDF"
    >
      <FileDownIcon className="h-3.5 w-3.5" />
      <span>{isPreparing ? "准备中" : "下载 PDF"}</span>
    </button>
  );
}