import React from 'react';
import Card from '@mui/material/Card';
import CardContent from '@mui/material/CardContent';
import Typography from '@mui/material/Typography';
import Link from '@mui/material/Link';
import './SourcePopup.css';

// Helper function to extract a friendly domain name from a URL.
const getDomainName = (url) => {
  try {
    if (!url) return 'Unknown Source';
    const hostname = new URL(url).hostname;
    const domain = hostname.startsWith('www.') ? hostname.slice(4) : hostname;
    const parts = domain.split('.');
    return parts[0].charAt(0).toUpperCase() + parts[0].slice(1);
  } catch (err) {
    console.error("Error parsing URL for domain name:", url, err);
    return 'Invalid URL';
  }
};

// Helper function for Levenshtein distance calculation
function levenshtein(a, b) {
  if (a.length === 0) return b.length;
  if (b.length === 0) return a.length;
  const matrix = [];
  for (let i = 0; i <= b.length; i++) matrix[i] = [i];
  for (let j = 0; j <= a.length; j++) matrix[0][j] = j;
  for (let i = 1; i <= b.length; i++) {
    for (let j = 1; j <= a.length; j++) {
      if (b.charAt(i - 1) === a.charAt(j - 1)) {
        matrix[i][j] = matrix[i - 1][j - 1];
      } else {
        matrix[i][j] = Math.min(
          matrix[i - 1][j - 1] + 1,
          matrix[i][j - 1] + 1,
          matrix[i - 1][j] + 1
        );
      }
    }
  }
  return matrix[b.length][a.length];
}

// SourcePopup component to display source information and excerpts
function SourcePopup({ 
  sourceData, 
  excerptsData, 
  position, 
  onMouseEnter, 
  onMouseLeave,
  statementText 
}) {
  if (!sourceData || !position) return null;

  const domain = getDomainName(sourceData.link);
  let hostname = '';
  try {
    hostname = sourceData.link ? new URL(sourceData.link).hostname : '';
  } catch (err) {
    hostname = sourceData.link || ''; // Fallback to link if URL parsing fails
  }

  let displayExcerpt = null;
  const sourceIdStr = String(sourceData.id);

  // Find the relevant excerpt
  if (excerptsData && Array.isArray(excerptsData) && statementText) {
    let foundExcerpt = null;
    let foundByFuzzy = false;
    const norm = s => s.replace(/\s+/g, ' ').trim();
    const lower = s => norm(s).toLowerCase();
    const statementNorm = norm(statementText);
    const statementLower = lower(statementText);
    console.log(`[SourcePopup] Searching for excerpt for source ID ${sourceIdStr}: ${statementText}`);

    // Iterate through the list of statement-to-excerpt mappings
    for (const entry of excerptsData) {
      const [thisStatement, sourcesMap] = Object.entries(entry)[0];
      const thisNorm = norm(thisStatement);
      const thisLower = lower(thisStatement);
      console.log(`[SourcePopup] Checking against statement: ${thisStatement}`);

      // Normalized exact match
      if (thisNorm === statementNorm && sourcesMap && sourceIdStr in sourcesMap) {
        foundExcerpt = sourcesMap[sourceIdStr];
        break;
      }
      // Case-insensitive match
      if (thisLower === statementLower && sourcesMap && sourceIdStr in sourcesMap) {
        foundExcerpt = sourcesMap[sourceIdStr];
        break;
      }
      // Substring containment
      if (
        (statementNorm && thisNorm && statementNorm.includes(thisNorm)) ||
        (thisNorm && statementNorm && thisNorm.includes(statementNorm))
      ) {
        if (sourcesMap && sourceIdStr in sourcesMap) {
          foundExcerpt = sourcesMap[sourceIdStr];
          foundByFuzzy = true;
          break;
        }
      }
      // Levenshtein distance
      if (
        levenshtein(statementNorm, thisNorm) <= 5 &&
        sourcesMap && sourceIdStr in sourcesMap
      ) {
        foundExcerpt = sourcesMap[sourceIdStr];
        foundByFuzzy = true;
        break;
      }
    }

    // Set displayExcerpt based on what was found
    if (foundExcerpt && foundExcerpt.toLowerCase() !== 'excerpt not found') {
      if (foundByFuzzy) {
        // Fuzzy match found an excerpt
        console.log("[SourcePopup] Fuzzy match found an excerpt:", foundExcerpt);
      } else {
        // Exact match found an excerpt
        console.log("[SourcePopup] Exact match found an excerpt:", foundExcerpt);
      }
      // Exact match found an excerpt
      displayExcerpt = foundExcerpt;
    } else if (foundExcerpt) {
      // Handle case where LLM explicitly said "Excerpt not found"
      displayExcerpt = "Relevant excerpt could not be automatically extracted.";
      console.log("[SourcePopup] Excerpt marked as not found or invalid type:", foundExcerpt);
    } else {
      // Excerpt for this specific source ID wasn't found in the loaded data
      displayExcerpt = "Excerpt not found for this citation.";
      console.log(`[SourcePopup] Excerpt not found for source ID ${sourceIdStr}: ${statementText}`);
    }
  }

  return (
    <div
      className="source-popup"
      style={{
        position: 'absolute', // Use absolute positioning
        top: `${position.top}px`,
        left: `${position.left}px`,
        transform: 'translate(-50%, -100%)', // Center above the reference
        zIndex: 1100, // Ensure it's above other content
      }}
      onMouseEnter={onMouseEnter} // Keep popup open when mouse enters it
      onMouseLeave={onMouseLeave} // Hide popup when mouse leaves it
    >
      <Card variant="outlined" className="source-popup-card">
        <CardContent>
          <Typography variant="subtitle2" component="div" className="source-popup-title" gutterBottom>
            <Link href={sourceData.link} target="_blank" rel="noopener noreferrer" underline="hover" color="inherit">
              {sourceData.title || 'Untitled Source'}
            </Link>
          </Typography>
          <Typography variant="body2" className="source-popup-link-info">
            {hostname && (
              <img
                src={`https://www.google.com/s2/favicons?domain=${hostname}&sz=16`}
                alt=""
                className="source-popup-icon"
              />
            )}
            <span className="source-popup-domain">{domain}</span>
          </Typography>
          {displayExcerpt !== null && (
             <Typography variant="caption" className="source-popup-excerpt" display="block" sx={{ mt: 1 }}>
               <Link
                  href={`${sourceData.link}#:~:text=${encodeURIComponent(displayExcerpt)}`}
                  target="_blank"
                  rel="noopener noreferrer"
                  underline="none"
                  color="inherit"
                >
                  {displayExcerpt}
                </Link>
             </Typography>
          )}
        </CardContent>
      </Card>
    </div>
  );
};

export default SourcePopup;