"use client";

import { useState, useEffect } from 'react';

export default function PdfViewer({ pdfUrl, pageNumber }) {
    const [loading, setLoading] = useState(true);
    const [error, setError] = useState(false);

    // Reset loading state when URL or page changes
    useEffect(() => {
        setLoading(true);
        setError(false);
    }, [pdfUrl, pageNumber]);

    if (!pdfUrl) {
        return (
            <div className="pdf-placeholder">
                <p>No PDF available for this document.</p>
            </div>
        );
    }

    // PDF pages in our data are 0-indexed; PDF.js viewer expects 1-indexed pages
    const viewerPage = (pageNumber ?? 0) + 1;

    // Proxy the PDF through our own API to bypass CORS restrictions.
    // Then use the browser's built-in PDF viewer via <object> tag.
    const proxyUrl = `/api/pdf-proxy?url=${encodeURIComponent(pdfUrl)}#page=${viewerPage}&zoom=75`;

    return (
        <div className="pdf-container">
            {loading && !error && (
                <div className="pdf-loading">
                    <div className="loading-spinner" />
                    <p>Loading PDF...</p>
                    <p className="pdf-loading-hint">This may take a moment for large documents.</p>
                </div>
            )}
            {error && (
                <div className="pdf-error">
                    <p>⚠️ Failed to load PDF</p>
                    <p className="pdf-error-hint">The document may be unavailable or too large.</p>
                    <a href={pdfUrl} target="_blank" rel="noopener noreferrer" className="btn btn-secondary">
                        Open PDF directly ↗
                    </a>
                </div>
            )}
            <iframe
                key={`pdf-${pdfUrl}-page-${viewerPage}`}
                src={proxyUrl}
                className="pdf-frame"
                title={`PDF Page ${viewerPage}`}
                allow="fullscreen"
                style={{ display: loading && !error ? 'none' : 'block' }}
                onLoad={() => setLoading(false)}
                onError={() => { setLoading(false); setError(true); }}
            />
        </div>
    );
}