import 'dart:async';
import 'dart:collection';
import 'package:flutter/foundation.dart';
import 'package:flutter_inappwebview/flutter_inappwebview.dart';

abstract class ILinkExtractionService {
  Future<String?> extractVideoUrl(String pageUrl);
}

class LinkExtractionService implements ILinkExtractionService {
  
  @override
  Future<String?> extractVideoUrl(String pageUrl) async {
    // 1. Zaten direkt bir video linkiyse hemen döndür
    if (_isVideoUrl(pageUrl)) return pageUrl;

    final completer = Completer<String?>();
    Timer? timeoutTimer;
    
    // HeadlessWebView'i yerel değişkene alıyoruz ki paralel çalışmalarda çakışmasın
    HeadlessInAppWebView? headlessWebView;

    // Temizlik ve Bellek Yönetimi
    void cleanup() {
      timeoutTimer?.cancel();
      headlessWebView?.dispose();
      headlessWebView = null;
    }

    // Bulunan URL'yi işleme
    void handleFoundUrl(String url) {
      if (!completer.isCompleted) {
        debugPrint("EXTRACTION: SUCCESS! Found: $url");
        cleanup();
        completer.complete(url);
      }
    }

    // Zaman aşımı (15 saniye)
    timeoutTimer = Timer(const Duration(seconds: 15), () {
      if (!completer.isCompleted) {
        debugPrint("EXTRACTION: Timeout - no video URL found");
        cleanup();
        completer.complete(null);
      }
    });

    // 2. UserScript: JS Kodunu Iframe'ler dahil tüm sayfalara DOM yüklenmeden ENJEKTE EDİYORUZ
    final snifferScript = UserScript(
      source: '''
        (function() {
          if (window.snifferInjected) return;
          window.snifferInjected = true;

          console.log("SNIFFER: Injected into frame: " + window.location.href);

          function reportUrl(url) {
            if (url && (url.includes('.m3u8') || url.includes('.mp4'))) {
              window.flutter_inappwebview.callHandler('foundVideoUrl', url);
            }
          }

          // 1. Override XMLHttpRequest
          var oldOpen = XMLHttpRequest.prototype.open;
          XMLHttpRequest.prototype.open = function(method, url) {
            reportUrl(url);
            return oldOpen.apply(this, arguments);
          };

          // 2. Override Fetch
          var oldFetch = window.fetch;
          window.fetch = function() {
            var url = (arguments[0] instanceof Request) ? arguments[0].url : arguments[0];
            if (url) reportUrl(url.toString());
            return oldFetch.apply(this, arguments);
          };

          // 3. Oynatma Butonlarına Tıklama (Tüm iframe'lerde çalışacak)
          window.clickPlayButtons = function() {
            var selectors = [
              '.play-that-video', '.play-button', '.vjs-big-play-button', 
              '[aria-label="Play"]', '.ytp-large-play-button', '.play-icon', 
              '#play', '.player-play', '.jw-display-icon-container',
              'div[class*="play"]', 'button[class*="play"]', 'svg[class*="play"]'
            ];
            
            selectors.forEach(function(sel) {
              try {
                document.querySelectorAll(sel).forEach(function(el) {
                  if (el.offsetWidth > 0 || el.offsetHeight > 0) {
                    el.click();
                  }
                });
              } catch(e) {}
            });

            // Video etiketlerini direkt kontrol et
            document.querySelectorAll('video').forEach(function(v) {
              if (v.src && v.src.length > 5) reportUrl(v.src);
              v.querySelectorAll('source').forEach(function(s) {
                 if (s.src) reportUrl(s.src);
              });
            });
          };

          // HTML içindeki linkleri Regex ile tara
          var scanInterval = setInterval(function() {
            var html = document.documentElement.innerHTML;
            var match = html.match(/https?:\\/\\/[^"'\\s<>]+\\.(m3u8|mp4)[^"'\\s<>]*/i);
            if (match) reportUrl(match[0]);
          }, 1500);

        })();
      ''',
      injectionTime: UserScriptInjectionTime.AT_DOCUMENT_START, // Sayfa açılmadan hemen önce
      forMainFrameOnly: false, // ÇOK ÖNEMLİ: Iframe'lerin içine girmesi için false olmalı!
    );

    headlessWebView = HeadlessInAppWebView(
      initialUrlRequest: URLRequest(url: WebUri(pageUrl)),
      initialUserScripts: UnmodifiableListView<UserScript>([snifferScript]), // Scripti buradan veriyoruz
      initialSettings: InAppWebViewSettings(
        javaScriptEnabled: true,
        isInspectable: true,
        mediaPlaybackRequiresUserGesture: false, // ÇOK ÖNEMLİ: Videoların tıklanmadan yüklenmesine izin ver
        mixedContentMode: MixedContentMode.MIXED_CONTENT_ALWAYS_ALLOW,
        supportMultipleWindows: false,
        javaScriptCanOpenWindowsAutomatically: false,
        useShouldInterceptRequest: true,
        userAgent: "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36",
      ),
      onWebViewCreated: (controller) {
        // JS'den gelen sinyali dinle
        controller.addJavaScriptHandler(handlerName: 'foundVideoUrl', callback: (args) {
          if (args.isNotEmpty) {
            handleFoundUrl(args[0].toString());
          }
        });
      },
      onReceivedServerTrustAuthRequest: (controller, challenge) async {
        return ServerTrustAuthResponse(action: ServerTrustAuthResponseAction.PROCEED);
      },
      shouldInterceptRequest: (controller, request) async {
        final url = request.url.toString();
        if (_isVideoUrl(url)) {
          handleFoundUrl(url);
        }
        return null;
      },
      onLoadStop: (controller, url) async {
        debugPrint("EXTRACTION: Page loaded: $url");
        
        // JS yüklenmiş mi diye kontrol et ve butonlara tıkla
        for (int i = 0; i < 8; i++) {
          if (completer.isCompleted) break;
          await Future.delayed(const Duration(seconds: 1));
          if (completer.isCompleted) break;
          
          try {
            // WebView kapanmışsa hata fırlatmasını engellemek için try-catch
            await controller.evaluateJavascript(source: "if(window.clickPlayButtons) window.clickPlayButtons();");
          } catch (e) {
            debugPrint("WebView disposed before javascript execution.");
          }
        }
      },
    );

    await headlessWebView?.run();
    return completer.future;
  }

  bool _isVideoUrl(String url) {
    final lower = url.toLowerCase();
    if (lower.startsWith('data:') || lower.length < 10) return false;
    
    // Analitik veya reklam linklerini es geç
    if (lower.contains('google.com') || lower.contains('gstatic.com') || lower.contains('analytics')) return false;

    return lower.contains('.m3u8') ||
        lower.contains('.mp4') ||
        lower.contains('.mkv') ||
        lower.contains('/hls/') ||
        lower.contains('master.m3u8') ||
        lower.contains('index.m3u8') ||
        lower.contains('playlist.m3u8');
  }
}