import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../../core/constants.dart';
import '../../data/models/note.dart';
import '../../data/models/task.dart';
import '../../providers/notes_provider.dart';
import '../../providers/projects_provider.dart';
import '../../providers/tasks_provider.dart';
import '../../widgets/library_item_card.dart';

enum _LibraryFilter { all, notes, tasks, projects }

enum _TaskStatusFilter { all, todo, inProgress, done }

class LibraryScreen extends ConsumerStatefulWidget {
  const LibraryScreen({super.key});

  @override
  ConsumerState<LibraryScreen> createState() => _LibraryScreenState();
}

class _LibraryScreenState extends ConsumerState<LibraryScreen> {
  _LibraryFilter _filter = _LibraryFilter.all;
  _TaskStatusFilter _taskStatus = _TaskStatusFilter.all;
  bool _searchActive = false;
  String _searchQuery = '';
  final _searchController = TextEditingController();

  @override
  void dispose() {
    _searchController.dispose();
    super.dispose();
  }

  bool _matchesSearch(String text) {
    if (_searchQuery.isEmpty) return true;
    return text.toLowerCase().contains(_searchQuery.toLowerCase());
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final notesAsync = ref.watch(notesProvider);
    final tasksAsync = ref.watch(tasksProvider);
    final projectsAsync = ref.watch(projectsProvider);

    return Scaffold(
      appBar: AppBar(
        title: _searchActive
            ? TextField(
                controller: _searchController,
                autofocus: true,
                decoration: const InputDecoration(
                  hintText: 'Search…',
                  border: InputBorder.none,
                  isDense: true,
                ),
                onChanged: (q) => setState(() => _searchQuery = q),
              )
            : Text('Library', style: theme.textTheme.titleLarge),
        actions: [
          IconButton(
            icon: Icon(_searchActive ? Icons.close : Icons.search),
            onPressed: () => setState(() {
              _searchActive = !_searchActive;
              if (!_searchActive) {
                _searchQuery = '';
                _searchController.clear();
              }
            }),
          ),
        ],
      ),
      body: Column(
        children: [
          // ── Filter pills ──────────────────────────────────────────────────
          SingleChildScrollView(
            scrollDirection: Axis.horizontal,
            padding: const EdgeInsets.fromLTRB(12, 8, 12, 4),
            child: Row(
              children: _LibraryFilter.values.map((f) {
                final label = switch (f) {
                  _LibraryFilter.all      => 'All',
                  _LibraryFilter.notes    => 'Notes',
                  _LibraryFilter.tasks    => 'Tasks',
                  _LibraryFilter.projects => 'Projects',
                };
                final selected = _filter == f;
                return Padding(
                  padding: const EdgeInsets.only(right: 8),
                  child: FilterChip(
                    label: Text(label),
                    selected: selected,
                    onSelected: (_) => setState(() {
                      _filter = f;
                      _taskStatus = _TaskStatusFilter.all;
                    }),
                    selectedColor:
                        theme.colorScheme.primary.withValues(alpha: 0.18),
                    checkmarkColor: theme.colorScheme.primary,
                  ),
                );
              }).toList(),
            ),
          ),

          // ── Task status sub-filter (Tasks pill only) ───────────────────
          if (_filter == _LibraryFilter.tasks)
            SingleChildScrollView(
              scrollDirection: Axis.horizontal,
              padding: const EdgeInsets.fromLTRB(12, 0, 12, 4),
              child: Row(
                children: _TaskStatusFilter.values.map((s) {
                  final label = switch (s) {
                    _TaskStatusFilter.all        => 'All',
                    _TaskStatusFilter.todo       => 'To Do',
                    _TaskStatusFilter.inProgress => 'In Progress',
                    _TaskStatusFilter.done       => 'Done',
                  };
                  return Padding(
                    padding: const EdgeInsets.only(right: 8),
                    child: ChoiceChip(
                      label: Text(label),
                      selected: _taskStatus == s,
                      onSelected: (_) => setState(() => _taskStatus = s),
                      selectedColor:
                          theme.colorScheme.secondary.withValues(alpha: 0.15),
                    ),
                  );
                }).toList(),
              ),
            ),

          const Divider(height: 1),

          // ── Content ───────────────────────────────────────────────────────
          Expanded(
            child: switch (_filter) {
              _LibraryFilter.notes    => _buildNotesList(notesAsync),
              _LibraryFilter.tasks    => _buildTasksList(tasksAsync),
              _LibraryFilter.projects => _buildProjectsList(projectsAsync),
              _LibraryFilter.all      => _buildAllList(notesAsync, tasksAsync),
            },
          ),
        ],
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () => _showCreateSheet(context),
        child: const Icon(Icons.add),
      ),
    );
  }

  Widget _buildNotesList(AsyncValue<List<Note>> notesAsync) {
    return notesAsync.when(
      loading: () => const Center(child: CircularProgressIndicator()),
      error: (e, _) => Center(child: Text('Error: $e')),
      data: (notes) {
        final filtered = notes
            .where((n) => _matchesSearch(n.title) || _matchesSearch(n.body))
            .toList();
        if (filtered.isEmpty) {
          return const Center(child: Text('No notes found'));
        }
        return RefreshIndicator(
          onRefresh: () async => ref.invalidate(notesProvider),
          child: ListView.builder(
            itemCount: filtered.length,
            itemBuilder: (_, i) => NoteLibraryCard(note: filtered[i]),
          ),
        );
      },
    );
  }

  Widget _buildTasksList(AsyncValue<List<Task>> tasksAsync) {
    return tasksAsync.when(
      loading: () => const Center(child: CircularProgressIndicator()),
      error: (e, _) => Center(child: Text('Error: $e')),
      data: (tasks) {
        var filtered = tasks.where((t) => _matchesSearch(t.title)).toList();
        if (_taskStatus != _TaskStatusFilter.all) {
          final status = switch (_taskStatus) {
            _TaskStatusFilter.todo       => TaskStatus.todo,
            _TaskStatusFilter.inProgress => TaskStatus.inProgress,
            _TaskStatusFilter.done       => TaskStatus.done,
            _                            => TaskStatus.todo,
          };
          filtered = filtered.where((t) => t.status == status).toList();
        }
        if (filtered.isEmpty) {
          return const Center(child: Text('No tasks found'));
        }
        return RefreshIndicator(
          onRefresh: () async => ref.invalidate(tasksProvider),
          child: ListView.builder(
            itemCount: filtered.length,
            itemBuilder: (_, i) => TaskLibraryCard(task: filtered[i]),
          ),
        );
      },
    );
  }

  Widget _buildProjectsList(AsyncValue<List<dynamic>> projectsAsync) {
    return projectsAsync.when(
      loading: () => const Center(child: CircularProgressIndicator()),
      error: (e, _) => Center(child: Text('Error: $e')),
      data: (projects) {
        if (projects.isEmpty) {
          return const Center(child: Text('No projects'));
        }
        return RefreshIndicator(
          onRefresh: () async => ref.invalidate(projectsProvider),
          child: ListView.builder(
            itemCount: projects.length,
            itemBuilder: (_, i) =>
                ProjectLibraryCard(project: projects[i]),
          ),
        );
      },
    );
  }

  Widget _buildAllList(
    AsyncValue<List<Note>> notesAsync,
    AsyncValue<List<Task>> tasksAsync,
  ) {
    final notes = notesAsync.valueOrNull ?? [];
    final tasks = tasksAsync.valueOrNull ?? [];

    // Merge and sort by updatedAt desc
    final items = <(DateTime, Widget)>[];
    for (final n in notes) {
      if (_matchesSearch(n.title) || _matchesSearch(n.body)) {
        items.add((n.updatedAt, NoteLibraryCard(note: n)));
      }
    }
    for (final t in tasks) {
      if (_matchesSearch(t.title)) {
        items.add((t.updatedAt, TaskLibraryCard(task: t)));
      }
    }
    items.sort((a, b) => b.$1.compareTo(a.$1));

    if (notesAsync.isLoading || tasksAsync.isLoading) {
      return const Center(child: CircularProgressIndicator());
    }
    if (items.isEmpty) {
      return const Center(child: Text('Nothing here yet'));
    }
    return RefreshIndicator(
      onRefresh: () async {
        ref.invalidate(notesProvider);
        ref.invalidate(tasksProvider);
      },
      child: ListView.builder(
        itemCount: items.length,
        itemBuilder: (_, i) => items[i].$2,
      ),
    );
  }

  void _showCreateSheet(BuildContext context) {
    showModalBottomSheet<void>(
      context: context,
      builder: (_) => SafeArea(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            ListTile(
              leading: const Icon(Icons.article_outlined),
              title: const Text('New note'),
              onTap: () {
                Navigator.pop(context);
                context.push(Routes.noteNew);
              },
            ),
            ListTile(
              leading: const Icon(Icons.check_box_outlined),
              title: const Text('New task'),
              onTap: () {
                Navigator.pop(context);
                context.push(Routes.taskNew);
              },
            ),
          ],
        ),
      ),
    );
  }
}