/**
 * eBay Content Script
 * Wird auf eBay-Seiten ausgeführt und extrahiert Verkäufer-/Shop-Daten aus dem DOM
 */

// Message Listener für Parsing-Anfragen
chrome.runtime.onMessage.addListener((message, sender, sendResponse) => {
  if (message.action === "PARSE_EBAY") {
    try {
      const parsedData = parseEbayPage();
      sendResponse({ ok: true, data: parsedData });
    } catch (error) {
      // Niemals unhandled throws - immer graceful response
      sendResponse({ 
        ok: true, 
        data: {
          sellerId: "",
          shopName: "",
          market: extractMarketFromHostname(),
          status: "unknown",
          stats: {}
        }
      });
    }
    return true; // async response
  }

  if (message.action === "PARSE_PRODUCT_LIST") {
    try {
      const items = parseProductList();
      sendResponse({ ok: true, data: { items } });
    } catch (error) {
      // Niemals unhandled throws - immer graceful response
      console.error("Error parsing product list:", error);
      sendResponse({ 
        ok: false, 
        error: error.message || "Failed to parse product list"
      });
    }
    return true; // async response
  }
});

/**
 * Extrahiert Marktplatz aus hostname
 * @returns {string} Market Code (z.B. "DE", "US", "UK")
 */
function extractMarketFromHostname() {
  try {
    const hostname = window.location.hostname.toLowerCase();
    
    // eBay Domain-Patterns
    if (hostname.includes('.de') || hostname.includes('ebay.de')) {
      return 'DE';
    }
    if (hostname.includes('.com') && !hostname.includes('.uk')) {
      return 'US';
    }
    if (hostname.includes('.uk') || hostname.includes('ebay.co.uk')) {
      return 'UK';
    }
    if (hostname.includes('.fr') || hostname.includes('ebay.fr')) {
      return 'FR';
    }
    if (hostname.includes('.it') || hostname.includes('ebay.it')) {
      return 'IT';
    }
    if (hostname.includes('.es') || hostname.includes('ebay.es')) {
      return 'ES';
    }
    if (hostname.includes('.nl') || hostname.includes('ebay.nl')) {
      return 'NL';
    }
    if (hostname.includes('.at') || hostname.includes('ebay.at')) {
      return 'AT';
    }
    if (hostname.includes('.ch') || hostname.includes('ebay.ch')) {
      return 'CH';
    }
    
    // Fallback: erster Teil der Domain nach "ebay."
    const match = hostname.match(/ebay\.([a-z]{2,3})/);
    if (match && match[1]) {
      return match[1].toUpperCase();
    }
    
    return 'US'; // Default
  } catch (e) {
    return 'US';
  }
}

/**
 * Extrahiert Seller ID aus URL oder DOM
 * @returns {string} Seller ID
 */
function extractSellerId() {
  try {
    // Methode 1: URL-Patterns
    const url = window.location.href;
    const urlLower = url.toLowerCase();
    
    // Pattern: /usr/username oder /str/storename
    const usrMatch = url.match(/\/usr\/([^\/\?]+)/i);
    if (usrMatch && usrMatch[1]) {
      return usrMatch[1].trim();
    }
    
    const strMatch = url.match(/\/str\/([^\/\?]+)/i);
    if (strMatch && strMatch[1]) {
      return strMatch[1].trim();
    }
    
    // Methode 2: DOM-Elemente suchen
    // Suche nach verschiedenen Selektoren, die Seller-ID enthalten könnten
    const possibleSelectors = [
      '[data-testid*="seller"]',
      '.seller-username',
      '.member-info-username',
      '[class*="seller-id"]',
      '[class*="username"]',
      '[id*="seller"]'
    ];
    
    for (const selector of possibleSelectors) {
      try {
        const element = document.querySelector(selector);
        if (element) {
          const text = element.textContent?.trim();
          if (text && text.length > 0 && text.length < 100) {
            return text;
          }
        }
      } catch (e) {
        // Continue to next selector
      }
    }
    
    // Methode 3: Meta-Tags
    try {
      const metaSeller = document.querySelector('meta[property*="seller"], meta[name*="seller"]');
      if (metaSeller && metaSeller.content) {
        return metaSeller.content.trim();
      }
    } catch (e) {
      // Continue
    }
    
    return ""; // Nicht gefunden
  } catch (e) {
    return "";
  }
}

/**
 * Extrahiert Shop Name aus DOM
 * @returns {string} Shop Name
 */
function extractShopName() {
  try {
    // Methode 1: Shop-Name aus Storefront-Link extrahieren
    // Pattern: <a href="/str/storename" data-track="...">Shop Name</a>
    try {
      const storefrontLinks = document.querySelectorAll('a[href*="/str/"]');
      for (const link of storefrontLinks) {
        // Prüfe ob Link data-track Attribut hat (typisch für Storefront-Links)
        if (link.hasAttribute('data-track') || link.href.includes('/str/')) {
          const linkText = link.textContent?.trim();
          if (linkText && linkText.length > 0 && linkText.length < 200) {
            // Prüfe dass es nicht nur ein URL-Pfad ist
            if (!linkText.match(/^https?:\/\//) && !linkText.match(/^\/str\//)) {
              return linkText;
            }
          }
        }
      }
    } catch (e) {
      // Continue to next method
    }
    
    // Methode 2: Spezifische Selektoren versuchen
    const shopNameSelectors = [
      'h1.shop-name',
      '.store-name',
      '[data-testid="store-name"]',
      '.store-title',
      '[class*="shop-name"]',
      '[class*="store-title"]',
      'h1[class*="store"]',
      'h1[class*="shop"]'
    ];
    
    for (const selector of shopNameSelectors) {
      try {
        const element = document.querySelector(selector);
        if (element) {
          const text = element.textContent?.trim();
          if (text && text.length > 0) {
            return text;
          }
        }
      } catch (e) {
        // Continue to next selector
      }
    }
    
    // Methode 3: document.title parsen
    try {
      const title = document.title || "";
      // Versuche Muster wie "Shop Name | eBay" zu extrahieren
      const titleMatch = title.match(/^(.+?)\s*[\|\-]\s*eBay/i);
      if (titleMatch && titleMatch[1]) {
        return titleMatch[1].trim();
      }
      // Wenn Titel einfach genug ist, verwende ihn direkt
      if (title && title.length < 100 && !title.toLowerCase().includes('ebay')) {
        return title.trim();
      }
    } catch (e) {
      // Continue
    }
    
    // Methode 4: h1 Tag als Fallback
    try {
      const h1 = document.querySelector('h1');
      if (h1) {
        const text = h1.textContent?.trim();
        if (text && text.length > 0 && text.length < 200) {
          return text;
        }
      }
    } catch (e) {
      // Continue
    }
    
    return ""; // Nicht gefunden
  } catch (e) {
    return "";
  }
}

/**
 * Extrahiert "Artikel verkauft" aus Storefront-Profilen
 * @returns {number|null} Anzahl verkaufter Artikel oder null
 */
function extractItemsSold() {
  try {
    // Suche nach Container
    const container = document.querySelector(".str-seller-card__store-stats-content");
    if (!container) {
      return null;
    }

    // Finde div children, die "Artikel verkauft" enthalten
    const divs = container.querySelectorAll("div");
    for (const div of divs) {
      const divText = div.textContent || "";
      if (divText.includes("Artikel verkauft")) {
        // Suche nach span mit Klasse str-text-span BOLD (Klasse kann als "str-text-span BOLD" sein)
        const span1 = div.querySelector("span.str-text-span.BOLD");
        const span2 = div.querySelector("span.BOLD");
        const span3 = div.querySelector('span[class*="BOLD"]');
        const span = span1 || span2 || span3;
        if (span) {
          let valueText = span.textContent?.trim() || "";
          
          // Normalisierung: Entferne Leerzeichen
          valueText = valueText.replace(/\s/g, "");
          
          // Ersetze Tausendertrenner (. und ,) durch leeren String
          valueText = valueText.replace(/[.,]/g, "");
          
          // Nur Digits behalten
          valueText = valueText.replace(/\D/g, "");
          
          // Parse zu Integer
          if (valueText.length > 0) {
            const parsedValue = parseInt(valueText, 10);
            if (!isNaN(parsedValue) && parsedValue >= 0) {
              return parsedValue;
            }
          }
        }
        
        // Fallback: Regex auf div-Text, falls Struktur abweicht
        const regexMatch = divText.match(/([\d.,]+)\s*Artikel\s*verkauft/i);
        if (regexMatch && regexMatch[1]) {
          let valueText = regexMatch[1].trim();
          valueText = valueText.replace(/\s/g, "").replace(/[.,]/g, "").replace(/\D/g, "");
          if (valueText.length > 0) {
            const parsedValue = parseInt(valueText, 10);
            if (!isNaN(parsedValue) && parsedValue >= 0) {
              return parsedValue;
            }
          }
        }
      }
    }
    
    return null;
  } catch (e) {
    // Graceful fallback bei Fehlern
    return null;
  }
}

/**
 * Extrahiert Stats aus DOM (Feedback Score, Positive Rate, etc.)
 * @returns {object} Stats Objekt
 */
function extractStats() {
  const stats = {};
  
  try {
    const pageText = document.body?.textContent || "";
    
    // Feedback Score
    try {
      const feedbackScorePatterns = [
        /feedback\s*score[:\s]+(\d+)/i,
        /(?:score|bewertung)[:\s]+(\d+)/i,
        /(\d+)\s*feedback/i
      ];
      
      for (const pattern of feedbackScorePatterns) {
        const match = pageText.match(pattern);
        if (match && match[1]) {
          const score = parseInt(match[1], 10);
          if (!isNaN(score) && score >= 0) {
            stats.feedbackScore = score;
            break;
          }
        }
      }
    } catch (e) {
      // Continue
    }
    
    // Positive Rate (%)
    try {
      const positiveRatePatterns = [
        /positive[:\s]+(\d+\.?\d*)\s*%/i,
        /(\d+\.?\d*)\s*%\s*positive/i,
        /(?:rate|quote)[:\s]+(\d+\.?\d*)\s*%/i
      ];
      
      for (const pattern of positiveRatePatterns) {
        const match = pageText.match(pattern);
        if (match && match[1]) {
          const rate = parseFloat(match[1]);
          if (!isNaN(rate) && rate >= 0 && rate <= 100) {
            stats.positiveRate = rate;
            break;
          }
        }
      }
    } catch (e) {
      // Continue
    }
    
    // Feedback Count
    try {
      const feedbackCountPatterns = [
        /(\d+)\s*(?:bewertungen|ratings|feedbacks?)/i,
        /(?:count|anzahl)[:\s]+(\d+)/i
      ];
      
      for (const pattern of feedbackCountPatterns) {
        const match = pageText.match(pattern);
        if (match && match[1]) {
          const count = parseInt(match[1], 10);
          if (!isNaN(count) && count >= 0) {
            stats.feedbackCount = count;
            break;
          }
        }
      }
    } catch (e) {
      // Continue
    }
    
    // Items for Sale
    try {
      const itemsPatterns = [
        /items?\s*(?:for\s*)?sale[:\s]+(\d+)/i,
        /(\d+)\s*artikel/i,
        /(\d+)\s*(?:items?|artikel)\s*(?:for\s*)?sale/i
      ];
      
      for (const pattern of itemsPatterns) {
        const match = pageText.match(pattern);
        if (match && match[1]) {
          const items = parseInt(match[1], 10);
          if (!isNaN(items) && items >= 0) {
            stats.itemsForSale = items;
            break;
          }
        }
      }
    } catch (e) {
      // Continue
    }
    
    // Member Since
    try {
      const memberSincePatterns = [
        /member\s*since[:\s]+(\d{1,2}[\/\-\.]\d{1,2}[\/\-\.]\d{2,4})/i,
        /mitglied\s*seit[:\s]+(\d{1,2}[\/\-\.]\d{1,2}[\/\-\.]\d{2,4})/i,
        /(?:since|seit)[:\s]+(\d{4})/i
      ];
      
      for (const pattern of memberSincePatterns) {
        const match = pageText.match(pattern);
        if (match && match[1]) {
          stats.memberSince = match[1].trim();
          break;
        }
      }
    } catch (e) {
      // Continue
    }
    
    // Items Sold (Artikel verkauft)
    try {
      const itemsSold = extractItemsSold();
      if (itemsSold !== null) {
        stats.itemsSold = itemsSold;
      }
    } catch (e) {
      // Continue
    }
    
  } catch (e) {
    // Return empty stats object
  }
  
  return stats;
}

/**
 * Haupt-Parsing-Funktion
 * @returns {object} Parsed eBay Account Data
 */
function parseEbayPage() {
  try {
    const sellerId = extractSellerId();
    const shopName = extractShopName();
    const market = extractMarketFromHostname();
    const stats = extractStats();
    
    // Status bestimmen: "active" wenn wir mindestens Shop Name oder Seller ID haben
    const status = (sellerId || shopName) ? "active" : "unknown";
    
    return {
      sellerId: sellerId || "",
      shopName: shopName || "",
      market: market,
      status: status,
      stats: stats
    };
  } catch (error) {
    // Graceful fallback
    return {
      sellerId: "",
      shopName: "",
      market: extractMarketFromHostname(),
      status: "unknown",
      stats: {}
    };
  }
}

/**
 * Parst Produktliste von eBay Storefront oder Seller Listings
 * @returns {Array} Array von Produkt-Items
 */
function parseProductList() {
  try {
    const url = window.location.href;
    const urlLower = url.toLowerCase();
    
    // Determine page type
    const isStorePage = urlLower.includes('/str/') || urlLower.includes('/store/');
    const isSellerPage = urlLower.includes('/usr/');
    
    // Check if seller profile without items (try to find link to listings)
    if (isSellerPage && !isStorePage) {
      const itemsLink = document.querySelector('a[href*="/usr/"][href*="?items="]') ||
                        document.querySelector('a[href*="schid=mksr"]') ||
                        Array.from(document.querySelectorAll('a')).find(a => {
                          const text = (a.textContent || '').toLowerCase();
                          return text.includes('artikel') || text.includes('angebote') || 
                                 text.includes('items for sale') || text.includes('see all items');
                        });
      
      if (!itemsLink) {
        // Try to find item cards directly
        const hasItems = findItemLinks().length > 0;
        if (!hasItems) {
          throw new Error("no_items_page");
        }
      }
    }
    
    // Extract items
    const items = findItemLinks();
    
    if (items.length === 0) {
      throw new Error("no_items_found");
    }
    
    // Parse each item
    const parsedItems = [];
    const seenIds = new Set();
    
    for (const itemLink of items) {
      try {
        const item = parseItemFromLink(itemLink);
        
        // Deduplicate by platformProductId
        if (item.platformProductId && !seenIds.has(item.platformProductId)) {
          seenIds.add(item.platformProductId);
          parsedItems.push(item);
        }
      } catch (e) {
        // Continue with next item if one fails
        console.warn("Failed to parse item:", e);
      }
    }
    
    // Return max 60 items (first page)
    return parsedItems.slice(0, 60);
    
  } catch (error) {
    // Re-throw to be caught by message handler
    throw error;
  }
}

/**
 * Findet Item-Links auf der Seite
 * @returns {Array} Array von Link-Elementen
 */
function findItemLinks() {
  const links = [];
  
  try {
    // Multiple selector fallbacks for item cards
    const selectors = [
      'a[href*="/itm/"]',           // Direct item links
      '.s-item a[href*="/itm/"]',   // Search result items
      '.srp-results .s-item a',     // Search results
      '.ebay-item-card a[href*="/itm/"]', // Item cards
      '[class*="item-card"] a[href*="/itm/"]', // Generic item cards
    ];
    
    for (const selector of selectors) {
      try {
        const found = document.querySelectorAll(selector);
        if (found.length > 0) {
          // Filter out duplicates by href
          const hrefs = new Set();
          for (const link of found) {
            const href = link.href || link.getAttribute('href');
            if (href && href.includes('/itm/') && !hrefs.has(href)) {
              hrefs.add(href);
              links.push(link);
            }
          }
          if (links.length > 0) break; // Found items, stop trying other selectors
        }
      } catch (e) {
        // Continue to next selector
      }
    }
  } catch (e) {
    // Return empty array on error
  }
  
  return links;
}

/**
 * Parst ein einzelnes Item aus einem Link-Element
 * @param {Element} itemLink - Link-Element zu einem eBay-Item
 * @returns {object} Parsed Item-Data
 */
function parseItemFromLink(itemLink) {
  const item = {
    platformProductId: null,
    title: "",
    price: null,
    currency: null,
    url: "",
    status: "active",
    category: null,
    condition: null
  };
  
  try {
    // URL (absolute)
    const href = itemLink.href || itemLink.getAttribute('href');
    if (href) {
      item.url = href.startsWith('http') ? href : new URL(href, window.location.origin).href;
      
      // Extract platformProductId from URL: /itm/<id> or ?item=<id>
      const itmMatch = item.url.match(/\/itm\/(\d+)/);
      if (itmMatch && itmMatch[1]) {
        item.platformProductId = itmMatch[1];
      } else {
        const itemParamMatch = item.url.match(/[?&]item=(\d+)/);
        if (itemParamMatch && itemParamMatch[1]) {
          item.platformProductId = itemParamMatch[1];
        }
      }
    }
    
    // Fallback: data attributes if present
    if (!item.platformProductId) {
      const dataItemId = itemLink.getAttribute('data-item-id') || 
                        itemLink.closest('[data-item-id]')?.getAttribute('data-item-id');
      if (dataItemId) {
        item.platformProductId = dataItemId;
      }
    }
    
    // Title: from link text or title element
    try {
      const titleElement = itemLink.querySelector('.s-item__title') ||
                          itemLink.querySelector('[class*="title"]') ||
                          itemLink.closest('.s-item')?.querySelector('.s-item__title');
      
      if (titleElement) {
        item.title = titleElement.textContent?.trim() || "";
      } else {
        // Fallback: link text itself
        item.title = itemLink.textContent?.trim() || "";
      }
      
      // Normalize title (remove extra whitespace)
      item.title = item.title.replace(/\s+/g, ' ').trim();
    } catch (e) {
      // Continue without title
    }
    
    // Price + Currency
    try {
      const itemCard = itemLink.closest('.s-item') || itemLink.closest('[class*="item-card"]');
      if (itemCard) {
        const priceElement = itemCard.querySelector('.s-item__price') ||
                            itemCard.querySelector('[class*="price"]') ||
                            itemCard.querySelector('.BOLD');
        
        if (priceElement) {
          const priceText = priceElement.textContent?.trim() || "";
          const parsed = parsePrice(priceText);
          item.price = parsed.price;
          item.currency = parsed.currency;
        }
      }
    } catch (e) {
      // Continue without price
    }
    
    // Category (optional)
    try {
      const categoryElement = itemLink.closest('.s-item')?.querySelector('[class*="category"]');
      if (categoryElement) {
        item.category = categoryElement.textContent?.trim() || null;
      }
    } catch (e) {
      // Continue without category
    }
    
    // Condition (optional)
    try {
      const conditionElement = itemLink.closest('.s-item')?.querySelector('[class*="condition"]');
      if (conditionElement) {
        item.condition = conditionElement.textContent?.trim() || null;
      }
    } catch (e) {
      // Continue without condition
    }
    
    // Status: default "active" (storefront shows active listings)
    // Could check for "ended" indicators, but MVP keeps it simple
    item.status = "active";
    
  } catch (e) {
    // Continue with partial data
    console.warn("Error parsing item:", e);
  }
  
  return item;
}

/**
 * Parst Preis-String in Zahl und Währung
 * @param {string} priceText - Preis-String z.B. "EUR 12,99" oder "$15.50"
 * @returns {object} { price: number|null, currency: string|null }
 */
function parsePrice(priceText) {
  const result = { price: null, currency: null };
  
  try {
    if (!priceText) return result;
    
    // Extract currency symbols/codes
    const currencyMatch = priceText.match(/(EUR|USD|GBP|€|\$|£)/i);
    if (currencyMatch) {
      const currencyCode = currencyMatch[1].toUpperCase();
      if (currencyCode === '€') result.currency = 'EUR';
      else if (currencyCode === '$') result.currency = 'USD';
      else if (currencyCode === '£') result.currency = 'GBP';
      else result.currency = currencyCode;
    }
    
    // Extract numeric value (handle both comma and dot as decimal separator)
    const normalized = priceText
      .replace(/[^\d,.-]/g, '') // Remove non-numeric except , . -
      .replace(/\./g, '') // Remove thousand separators (assume dot)
      .replace(',', '.'); // Replace comma with dot for decimal
    
    const price = parseFloat(normalized);
    if (!isNaN(price) && price >= 0) {
      result.price = price;
    }
  } catch (e) {
    // Return null values on error
  }
  
  return result;
}