"use client";

import { useEffect, useRef, useState } from "react";
import { Button } from "@/components/ui/button";
import { X, Printer, Download, Loader2, ExternalLink } from "lucide-react";

/**
 * In-app PDF viewer modal for a generated quote PDF.
 *
 * Flow:
 *   - On mount, fetches the PDF binary from the API as a Blob, creates
 *     a local blob URL, and renders it inside an `<iframe>` (browser
 *     native PDF viewer).
 *   - Print button: asks the iframe to call its own `window.print()` —
 *     prints the PDF directly, not the surrounding page chrome.
 *   - Download button: fetches again with `?download=1` to get a
 *     `Content-Disposition: attachment` response, triggers a save dialog.
 *   - Open in new tab: opens the blob URL in a new browser tab for
 *     users who want a full-page viewing experience instead of the
 *     in-modal preview.
 *   - Close: revokes the blob URL and unmounts.
 */
export interface QuotePdfViewerProps {
  open: boolean;
  quoteId: string;
  attachmentId: string;
  filename: string;
  onClose: () => void;
}

export function QuotePdfViewer({
  open,
  quoteId,
  attachmentId,
  filename,
  onClose,
}: QuotePdfViewerProps) {
  const [blobUrl, setBlobUrl] = useState<string | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const iframeRef = useRef<HTMLIFrameElement | null>(null);

  // Fetch + blob-URL-ify when the modal opens.
  useEffect(() => {
    if (!open) {
      // Cleanup when closing.
      setBlobUrl(null);
      setLoading(true);
      setError(null);
      return;
    }

    let cancelled = false;
    setLoading(true);
    setError(null);

    (async () => {
      try {
        const res = await fetch(
          `/api/v1/quotes/${quoteId}/pdf?attachmentId=${encodeURIComponent(attachmentId)}`
        );
        if (!res.ok) {
          throw new Error(`Failed to load PDF (${res.status})`);
        }
        const blob = await res.blob();
        if (cancelled) return;
        const url = URL.createObjectURL(blob);
        setBlobUrl(url);
        setLoading(false);
      } catch (err) {
        if (cancelled) return;
        setError(err instanceof Error ? err.message : String(err));
        setLoading(false);
      }
    })();

    return () => {
      cancelled = true;
    };
  }, [open, quoteId, attachmentId]);

  // Revoke blob URL on unmount or when it changes.
  useEffect(() => {
    return () => {
      if (blobUrl) URL.revokeObjectURL(blobUrl);
    };
  }, [blobUrl]);

  // Esc closes the modal.
  useEffect(() => {
    if (!open) return;
    const handler = (e: KeyboardEvent) => {
      if (e.key === "Escape") onClose();
    };
    window.addEventListener("keydown", handler);
    return () => window.removeEventListener("keydown", handler);
  }, [open, onClose]);

  if (!open) return null;

  const handlePrint = () => {
    // Print from inside the iframe so only the PDF prints, not the modal chrome.
    try {
      iframeRef.current?.contentWindow?.print();
    } catch {
      // Some browsers block cross-frame print; fall back to opening the blob URL.
      if (blobUrl) window.open(blobUrl, "_blank");
    }
  };

  const handleDownload = async () => {
    // Re-fetch with ?download=1 so the server sends Content-Disposition: attachment.
    const url = `/api/v1/quotes/${quoteId}/pdf?attachmentId=${encodeURIComponent(
      attachmentId
    )}&download=1`;
    // Anchor click is the cleanest cross-browser way to trigger a save dialog.
    const a = document.createElement("a");
    a.href = url;
    a.download = filename;
    document.body.appendChild(a);
    a.click();
    a.remove();
  };

  const handleOpenInNewTab = () => {
    if (!blobUrl) return;
    // Open the same blob URL in a new tab — the browser's built-in
    // PDF viewer takes over (with its own toolbar / download button).
    window.open(blobUrl, "_blank", "noopener,noreferrer");
  };

  return (
    <div
      className="fixed inset-0 z-50 flex flex-col bg-black/70"
      role="dialog"
      aria-modal="true"
      aria-label="Quote PDF viewer"
      data-testid="quote-pdf-viewer"
    >
      {/* Toolbar */}
      <div className="flex items-center justify-between gap-2 border-b border-white/10 bg-zinc-900 px-4 py-2 text-white">
        <div className="flex items-center gap-3 min-w-0">
          <span className="font-medium truncate" title={filename}>
            {filename}
          </span>
        </div>
        <div className="flex items-center gap-2">
          <Button
            type="button"
            variant="secondary"
            size="sm"
            onClick={handlePrint}
            disabled={!blobUrl || loading}
            data-testid="quote-pdf-print"
          >
            <Printer className="mr-1 h-4 w-4" />
            Print
          </Button>
          <Button
            type="button"
            variant="secondary"
            size="sm"
            onClick={handleDownload}
            disabled={!blobUrl || loading}
            data-testid="quote-pdf-download"
          >
            <Download className="mr-1 h-4 w-4" />
            Download
          </Button>
          <Button
            type="button"
            variant="secondary"
            size="sm"
            onClick={handleOpenInNewTab}
            disabled={!blobUrl || loading}
            data-testid="quote-pdf-open-new-tab"
          >
            <ExternalLink className="mr-1 h-4 w-4" />
            Open in new tab
          </Button>
          <Button
            type="button"
            variant="ghost"
            size="icon"
            onClick={onClose}
            className="text-white hover:bg-white/10"
            aria-label="Close PDF viewer"
            data-testid="quote-pdf-close"
          >
            <X className="h-5 w-5" />
          </Button>
        </div>
      </div>

      {/* PDF area */}
      <div className="relative flex-1 bg-zinc-800">
        {loading ? (
          <div className="absolute inset-0 flex items-center justify-center text-white">
            <Loader2 className="h-6 w-6 animate-spin mr-2" />
            Loading PDF…
          </div>
        ) : error ? (
          <div className="absolute inset-0 flex items-center justify-center text-destructive">
            {error}
          </div>
        ) : blobUrl ? (
          <iframe
            ref={iframeRef}
            src={blobUrl}
            title={filename}
            className="h-full w-full border-0 bg-white"
            data-testid="quote-pdf-iframe"
          />
        ) : null}
      </div>
    </div>
  );
}

export default QuotePdfViewer;