import 'package:cached_network_image/cached_network_image.dart';
import 'package:flutter/material.dart';
import 'package:f0ckapp/services/api.dart';
import 'package:f0ckapp/models/mediaitem.dart';
import 'package:f0ckapp/screens/detailview.dart';
import 'dart:async';

class MediaGrid extends StatefulWidget {
  const MediaGrid({super.key});

  @override
  State createState() => _MediaGridState();
}

class _MediaGridState extends State<MediaGrid> {
  final ScrollController _scrollController = ScrollController();
  final String _version = '1.0.21+21';
  List<MediaItem> mediaItems = [];
  bool isLoading = false;
  Timer? _debounceTimer;
  Completer<void>? _navigationCompleter;
  int _crossAxisCount = 0;
  String _selectedType = 'alles';
  int _selectedMode = 0;
  bool _random = false;
  final List<String> _modes = ["sfw", "nsfw", "untagged", "all"];

  @override
  void initState() {
    super.initState();
    _loadMedia();
    _scrollController.addListener(() {
      if (_scrollController.position.pixels >=
          _scrollController.position.maxScrollExtent - 100) {
        _debounceLoadMedia();
      }
    });
  }

  void _debounceLoadMedia() {
    _debounceTimer?.cancel();
    _debounceTimer = Timer(const Duration(milliseconds: 500), _loadMedia);
  }

  int _calculateCrossAxisCount(BuildContext context) {
    if (_crossAxisCount != 0) {
      return _crossAxisCount;
    }

    double screenWidth = MediaQuery.of(context).size.width;
    int columnCount = (screenWidth / 110).clamp(3, 5).toInt();

    return columnCount;
  }

  Future<void> _loadMedia() async {
    if (isLoading) return;
    setState(() => isLoading = true);

    try {
      final newMedia = await fetchMedia(
        older: mediaItems.isNotEmpty ? mediaItems.last.id.toString() : null,
        type: _selectedType,
        mode: _selectedMode,
        random: _random,
      );
      if (mounted) {
        setState(() => mediaItems.addAll(newMedia));
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Fehler beim Laden der Medien: $e')),
        );
      }
    } finally {
      if (mounted) setState(() => isLoading = false);
    }
  }

  Future<void> _refreshMedia() async {
    setState(() => isLoading = true);
    try {
      final freshMedia = await fetchMedia(
        older: null,
        type: _selectedType,
        mode: _selectedMode,
        random: _random,
      );
      if (mounted) {
        setState(() {
          mediaItems.clear();
          mediaItems.addAll(freshMedia);
        });
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Fehler beim Aktualisieren: $e')),
        );
      }
    } finally {
      if (mounted) setState(() => isLoading = false);
    }
  }

  Future<void> _navigateToDetail(MediaItem item) async {
    if (_navigationCompleter?.isCompleted == false) return;

    _navigationCompleter = Completer();
    try {
      if (mounted) {
        await Navigator.push(
          context,
          MaterialPageRoute(
            builder: (context) => DetailView(
              initialItemId: item.id,
              mediaItems: mediaItems,
              type: _selectedType,
              mode: _selectedMode,
              random: _random,
            ),
          ),
        );
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Fehler beim Laden der Details: $e')),
        );
      }
    } finally {
      _navigationCompleter?.complete();
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        centerTitle: true,
        backgroundColor: const Color.fromARGB(255, 43, 43, 43),
        foregroundColor: const Color.fromARGB(255, 255, 255, 255),
        title: Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            Text('f0ck v$_version'),
            Checkbox(
              value: _random,
              onChanged: (bool? value) {
                setState(() {
                  _random = !_random;
                  _refreshMedia();
                });
              },
            )
          ]
        )
      ),
      bottomNavigationBar: BottomAppBar(
        color: const Color.fromARGB(255, 43, 43, 43),
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 16.0),
          child: Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            crossAxisAlignment: CrossAxisAlignment.end,
            children: [
              DropdownButton<String>(
                value: _selectedType,
                dropdownColor: const Color.fromARGB(255, 43, 43, 43),
                iconEnabledColor: Colors.white,
                items: ["alles", "image", "video", "audio"].map((String value) {
                  return DropdownMenuItem<String>(
                    value: value,
                    child: Text(value, style: TextStyle(color: Colors.white)),
                  );
                }).toList(),
                onChanged: (String? newValue) {
                  if (newValue != null) {
                    setState(() {
                      _selectedType = newValue;
                      _refreshMedia();
                    });
                  }
                },
              ),
              DropdownButton<String>(
                value: _modes[_selectedMode],
                dropdownColor: const Color.fromARGB(255, 43, 43, 43),
                iconEnabledColor: Colors.white,
                items: _modes.map((String value) {
                  return DropdownMenuItem<String>(
                    value: value,
                    child: Text(value, style: TextStyle(color: Colors.white)),
                  );
                }).toList(),
                onChanged: (String? newValue) {
                  if (newValue != null) {
                    setState(() {
                      _selectedMode = _modes.indexOf(newValue);
                      _refreshMedia();
                    });
                  }
                },
              ),
              DropdownButton<int>(
                value: _crossAxisCount,
                dropdownColor: const Color.fromARGB(255, 43, 43, 43),
                iconEnabledColor: Colors.white,
                items: [0, 3, 4].map((int value) {
                  return DropdownMenuItem<int>(
                    value: value,
                    child: Text(
                      value == 0 ? 'auto' : '$value Spalten',
                      style: TextStyle(color: Colors.white),
                    ),
                  );
                }).toList(),
                onChanged: (int? newValue) {
                  if (newValue != null) {
                    setState(() {
                      _crossAxisCount = newValue;
                    });
                  }
                },
              ),
            ],
          ),
        ),
      ),
      body: RefreshIndicator(
        onRefresh: _refreshMedia,
        child: GridView.builder(
          controller: _scrollController,
          gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
            crossAxisCount: _calculateCrossAxisCount(context),
            crossAxisSpacing: 5.0,
            mainAxisSpacing: 5.0,
          ),
          itemCount: mediaItems.length + (isLoading ? 1 : 0),
          itemBuilder: (context, index) {
            if (index >= mediaItems.length) {
              return const Center(child: CircularProgressIndicator());
            }
            final item = mediaItems[index];

            return InkWell(
              onTap: () => _navigateToDetail(item),
              child: Stack(
                fit: StackFit.expand,
                children: <Widget>[
                  CachedNetworkImage(
                    imageUrl: item.thumbnailUrl,
                    fit: BoxFit.cover,
                    placeholder: (context, url) => CircularProgressIndicator(),
                    errorWidget: (context, url, error) => Icon(Icons.error),
                  ),
                  Align(
                    alignment: FractionalOffset.bottomRight,
                    child: Icon(
                      Icons.square,
                      color: switch (item.mode) {
                        1 => Colors.green,
                        2 => Colors.red,
                        _ => Colors.yellow
                      },
                      size: 15.0
                    ),
                  ),
                ],
              ),
            );
          },
        ),
      ),
    );
  }

  @override
  void dispose() {
    _scrollController.dispose();
    _debounceTimer?.cancel();
    super.dispose();
  }
}