import { fetchWithCors } from '../utils/corsProxy';
import { RSS_TO_JSON_API, debugLog, debugWarn } from '../utils/constants';

/**
 * Determine source type from URL
 * @param {string} url - The URL to analyze
 * @returns {string} - 'json' | 'rss' | 'html'
 */
export function detectSourceType(url) {
  const urlLower = url.toLowerCase();

  if (urlLower.includes('.json')) return 'json';
  if (urlLower.includes('.rss') ||
      urlLower.includes('.xml') ||
      urlLower.includes('/feed') ||
      urlLower.includes('rss')) return 'rss';

  return 'html'; // Default to HTML scraping
}

/**
 * Parse JSON endpoint
 * @param {string} url - The JSON URL
 * @param {string} corsProxy - CORS proxy URL
 * @returns {Promise<any>} - Parsed JSON data
 */
export async function parseJSON(url, corsProxy) {
  try {
    // Reddit's JSON API blocks unauthenticated browser CORS requests (returns 403).
    // Route through the local proxy server, which fetches server-side with a proper
    // User-Agent header that Reddit accepts.
    if (url.includes('reddit.com')) {
      const proxyPort = import.meta.env.REACT_APP_PROXY_PORT || '5374';
      const proxyUrl = `http://localhost:${proxyPort}/api/scrape?url=${encodeURIComponent(url)}`;
      const response = await fetch(proxyUrl);
      if (!response.ok) {
        throw new Error(`Local proxy returned ${response.status} for Reddit URL`);
      }
      const text = await response.text();
      return JSON.parse(text);
    }

    const data = await fetchWithCors(url);
    return data;
  } catch (error) {
    console.error(`Error parsing JSON from ${url}:`, error);
    throw error;
  }
}

/**
 * Parse RSS feed
 * @param {string} url - The RSS feed URL
 * @returns {Promise<any>} - Parsed RSS data
 */
export async function parseRSS(url) {
  try {
    // Use RSS to JSON service
    const rssUrl = `${RSS_TO_JSON_API}?rss_url=${encodeURIComponent(url)}`;
    const response = await fetch(rssUrl);

    if (!response.ok) {
      throw new Error(`RSS parse failed: ${response.status}`);
    }

    const data = await response.json();

    // Check if RSS2JSON returned an error
    if (data.status !== 'ok') {
      throw new Error(data.message || 'RSS feed parsing failed');
    }

    return data;
  } catch (error) {
    console.error(`Error parsing RSS from ${url}:`, error);
    throw error;
  }
}

/**
 * Strip HTML tags and extract meaningful text content
 * @param {string} html - Raw HTML string
 * @returns {string} - Cleaned text content
 */
export function cleanHTML(html) {
  if (typeof html !== 'string') return '';

  let text = html;

  // Remove script, style, nav, header, footer, aside blocks entirely
  text = text.replace(/<script[\s\S]*?<\/script>/gi, '');
  text = text.replace(/<style[\s\S]*?<\/style>/gi, '');
  text = text.replace(/<nav[\s\S]*?<\/nav>/gi, '');
  text = text.replace(/<footer[\s\S]*?<\/footer>/gi, '');
  text = text.replace(/<aside[\s\S]*?<\/aside>/gi, '');
  text = text.replace(/<noscript[\s\S]*?<\/noscript>/gi, '');
  text = text.replace(/<svg[\s\S]*?<\/svg>/gi, '');

  // Replace block-level tags with newlines to preserve structure
  text = text.replace(/<\/?(div|p|br|h[1-6]|li|tr|blockquote|section|article)[^>]*>/gi, '\n');

  // Strip all remaining HTML tags
  text = text.replace(/<[^>]+>/g, ' ');

  // Decode common HTML entities
  text = text.replace(/&amp;/g, '&');
  text = text.replace(/&lt;/g, '<');
  text = text.replace(/&gt;/g, '>');
  text = text.replace(/&quot;/g, '"');
  text = text.replace(/&#39;/g, "'");
  text = text.replace(/&nbsp;/g, ' ');
  text = text.replace(/&#\d+;/g, '');

  // Collapse whitespace: multiple spaces → single, multiple newlines → double
  text = text.replace(/[ \t]+/g, ' ');
  text = text.replace(/\n[ \t]+/g, '\n');
  text = text.replace(/\n{3,}/g, '\n\n');

  return text.trim();
}

/**
 * Parse HTML content via the local proxy server (avoids CORS issues)
 * Falls back to fetchWithCors if the proxy is unavailable.
 * @param {string} url - The HTML page URL
 * @param {string} corsProxy - CORS proxy URL (unused, kept for API compat)
 * @returns {Promise<Object>} - Object with URL and cleaned text content
 */
export async function parseHTML(url, corsProxy) {
  let rawHTML;

  try {
    // Use local proxy server to avoid CORS issues with arbitrary websites
    const proxyPort = import.meta.env.REACT_APP_PROXY_PORT || '5374';
    const proxyUrl = `http://localhost:${proxyPort}/api/scrape?url=${encodeURIComponent(url)}`;
    const response = await fetch(proxyUrl);

    if (!response.ok) {
      throw new Error(`Scrape proxy returned ${response.status}`);
    }

    rawHTML = await response.text();
  } catch (proxyError) {
    debugWarn(`Local scrape proxy failed for ${url}, falling back to CORS proxy:`, proxyError.message);
    try {
      const html = await fetchWithCors(url);
      rawHTML = typeof html === 'string' ? html : JSON.stringify(html);
    } catch (corsError) {
      console.error(`All fetch methods failed for ${url}:`, corsError);
      throw corsError;
    }
  }

  const cleanedText = cleanHTML(rawHTML);

  return {
    url: url,
    html: rawHTML,
    cleanedText: cleanedText,
    type: 'html',
    timestamp: Date.now()
  };
}

/**
 * Parse a source based on its detected type
 * @param {string} url - The URL to parse
 * @param {string} type - Optional type override
 * @returns {Promise<any>} - Parsed data
 */
export async function parseSource(url, type = null) {
  const sourceType = type || detectSourceType(url);

  switch(sourceType) {
    case 'json':
      return await parseJSON(url);

    case 'rss':
      return await parseRSS(url);

    case 'html':
      return await parseHTML(url);

    default:
      throw new Error(`Unknown source type: ${sourceType}`);
  }
}

/**
 * Extract meaningful content from HTML using Claude
 * This will be called later when Claude service is integrated
 * @param {string} html - The HTML content
 * @param {string} url - The source URL
 * @returns {Promise<Object>} - Extracted content
 */
export async function extractWithClaude(html, url) {
  // This function will be implemented when Claude service is ready
  // For now, return a placeholder structure
  return {
    url: url,
    content: html.substring(0, 5000), // Limit content for now
    extractedAt: Date.now(),
    needsClaudeProcessing: true
  };
}

/**
 * Condense data for Claude to reduce payload size
 * @param {Object} data - Full source data
 * @returns {Object} - Condensed data suitable for Claude
 */
export function condenseForClaude(data) {
    if (!data) return null;
    
    // Handle weather data - already compact
    if (data.type === 'weather') {
        return {
            type: 'weather',
            location: data.location,
            current: {
                temp: data.current?.temp,
                description: data.current?.description,
                humidity: data.current?.humidity,
                windSpeed: data.current?.windSpeed
            },
            forecast: data.forecast?.slice(0, 3)?.map(day => ({
                date: day.date,
                maxTemp: day.maxTemp,
                minTemp: day.minTemp,
                description: day.description
            }))
        };
    }
    
    // Handle Reddit data - needs major condensing
    if (data.type === 'reddit') {
        return {
            type: 'reddit',
            url: data.url,
            posts: data.posts?.slice(0, 10)?.map(post => ({
                title: post.title,
                score: post.score,
                comments: post.comments,
                subreddit: post.subreddit,
                // Truncate selftext to 200 chars
                summary: post.selftext ? 
                    (post.selftext.length > 200 ? 
                        post.selftext.substring(0, 197) + '...' : 
                        post.selftext) : null,
                url: post.url
            }))
        };
    }
    
    // Handle RSS feeds
    if (data.type === 'rss') {
        return {
            type: 'rss',
            feedTitle: data.feedTitle,
            items: data.items?.slice(0, 10)?.map(item => ({
                title: item.title,
                // Truncate description to 150 chars
                summary: item.description ? 
                    (item.description.length > 150 ? 
                        item.description.substring(0, 147) + '...' : 
                        item.description) : null,
                pubDate: item.pubDate
            }))
        };
    }
    
    // Handle webpage type (Claude-summarized HTML)
    if (data.type === 'webpage') {
        return {
            type: 'webpage',
            url: data.url,
            title: data.title,
            summary: data.summary,
            items: data.items?.slice(0, 5)?.map(item => ({
                title: item.title,
                date: item.date,
                summary: item.summary ? 
                    (item.summary.length > 200 ?
                        item.summary.substring(0, 197) + '...' :
                        item.summary) : null
            }))
        };
    }

    // Default for unknown types - just truncate if it's large
    if (data.type === 'unknown' && data.data) {
        const dataStr = JSON.stringify(data.data);
        if (dataStr.length > 1000) {
            return {
                type: 'unknown',
                url: data.url,
                summary: 'Data truncated for size',
                sample: dataStr.substring(0, 500) + '...'
            };
        }
    }
    
    return data;
}

/**
 * Condense multiple sources for Claude
 * @param {Object} sources - Object containing all source data
 * @returns {Object} - Condensed sources object
 */
export function condenseSourcesForClaude(sources) {
    const condensed = {};
    
    Object.entries(sources).forEach(([key, value]) => {
        if (Array.isArray(value)) {
            // Handle row arrays
            condensed[key] = value.map(item => condenseForClaude(item));
        } else {
            // Handle individual source objects
            condensed[key] = condenseForClaude(value);
        }
    });
    
    return condensed;
}

/**
 * Clean and standardize source data
 * @param {any} data - Raw source data
 * @param {string} sourceUrl - The source URL
 * @returns {Object} - Standardized data object
 */
export function standardizeSourceData(data, sourceUrl) {
    // Detect the source and format accordingly
    if (sourceUrl.includes('reddit.com') && data.data) {
        // Reddit JSON format
        return {
            type: 'reddit',
            url: sourceUrl,
            posts: data.data.children?.map(child => {
                const post = child.data;
                
                // Extract image URLs from different possible locations
                let images = [];
                let mainImage = null;
                
                // Check for direct image URL
                if (post.url && post.url.match(/\.(jpg|jpeg|png|gif|webp)$/i)) {
                    mainImage = post.url;
                } else if (post.url_overridden_by_dest && post.url_overridden_by_dest.match(/\.(jpg|jpeg|png|gif|webp)$/i)) {
                    mainImage = post.url_overridden_by_dest;
                }
                
                // Check preview object for images (most reliable source for Reddit images)
                if (!mainImage && post.preview && post.preview.images && post.preview.images.length > 0) {
                    const previewImage = post.preview.images[0];
                    
                    // Get the smallest resolution that's still reasonable quality
                    // Resolutions array is sorted from smallest to largest
                    if (previewImage.resolutions && previewImage.resolutions.length > 0) {
                        // Get resolution around 320-640px wide for optimal loading
                        const targetRes = previewImage.resolutions.find(r => r.width >= 320 && r.width <= 640) 
                                         || previewImage.resolutions[previewImage.resolutions.length - 1]
                                         || previewImage.resolutions[0];
                        mainImage = targetRes.url.replace(/&amp;/g, '&');
                    } else if (previewImage.source) {
                        // Fallback to source if no resolutions
                        mainImage = previewImage.source.url.replace(/&amp;/g, '&');
                    }
                }
                
                // Check for gallery images
                if (post.is_gallery && post.media_metadata) {
                    images = Object.values(post.media_metadata).map(media => {
                        // Get smallest reasonable resolution for gallery images
                        if (media.p && media.p.length > 0) {
                            // Find preview around 320-640px or use middle resolution
                            const targetPreview = media.p.find(p => p.x >= 320 && p.x <= 640)
                                                || media.p[Math.floor(media.p.length / 2)]
                                                || media.p[0];
                            return targetPreview.u.replace(/&amp;/g, '&');
                        } else if (media.s && media.s.u) {
                            // Fallback to source
                            return media.s.u.replace(/&amp;/g, '&');
                        }
                        return null;
                    }).filter(url => url !== null);
                    
                    // Use first gallery image as main if no other main image
                    if (!mainImage && images.length > 0) {
                        mainImage = images[0];
                    }
                }
                
                // Check for regular thumbnail (not "self", "default", "nsfw", "spoiler", etc.)
                let thumbnail = null;
                if (post.thumbnail && post.thumbnail.startsWith('http')) {
                    thumbnail = post.thumbnail;
                }
                
                // Use thumbnail as main image if no better option
                if (!mainImage && thumbnail && 
                    !thumbnail.includes('external-preview') && 
                    thumbnail !== 'self' && 
                    thumbnail !== 'default') {
                    mainImage = thumbnail;
                }
                
                return {
                    title: post.title,
                    url: post.url,
                    permalink: `https://reddit.com${post.permalink}`,
                    author: post.author,
                    score: post.score,
                    comments: post.num_comments,
                    created: post.created_utc,
                    thumbnail: thumbnail,
                    mainImage: mainImage,
                    galleryImages: images,
                    isGallery: post.is_gallery || false,
                    selftext: post.selftext,
                    subreddit: post.subreddit
                };
            }) || [],
            after: data.data.after,
            before: data.data.before
        };
    }


  if (data.items && data.feed) {
    // RSS feed format from rss2json
    return {
      type: 'rss',
      url: sourceUrl,
      feedTitle: data.feed.title,
      feedUrl: data.feed.url,
      items: data.items.map(item => ({
        title: item.title,
        link: item.link,
        description: item.description,
        pubDate: item.pubDate,
        author: item.author,
        categories: item.categories
      }))
    };
  }

  // Handle HTML / webpage data (from parseHTML)
  if (data.type === 'html' && data.cleanedText) {
    return {
      type: 'webpage',
      url: sourceUrl,
      cleanedText: data.cleanedText,
      // Will be populated by Claude summarization later
      title: null,
      summary: null,
      items: [],
      needsSummarization: true,
      fetchedAt: Date.now()
    };
  }

  // Default format for unknown sources
  return {
    type: 'unknown',
    url: sourceUrl,
    data: data,
    fetchedAt: Date.now()
  };
}