import 'package:flutter/material.dart';
import 'package:iconsax/iconsax.dart';
import 'package:animate_do/animate_do.dart';
import 'package:timeago/timeago.dart' as timeago;
import '../api/api.dart';

/// Conversations management page
///
/// Displays all conversations with details about messages, activity, and status.
/// Integrates with backend CQRS API for conversation listing and management.
class ConversationsPage extends StatefulWidget {
  const ConversationsPage({super.key});

  @override
  State<ConversationsPage> createState() => _ConversationsPageState();
}

class _ConversationsPageState extends State<ConversationsPage> {
  final CqrsApiClient _apiClient = CqrsApiClient(
    config: ApiClientConfig.development,
  );

  List<ConversationListItemDto>? _conversations;
  bool _isLoading = true;
  String? _errorMessage;
  String _filterStatus = 'all'; // all, active, inactive

  @override
  void initState() {
    super.initState();
    _loadConversations();
  }

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

  Future<void> _loadConversations() async {
    setState(() {
      _isLoading = true;
      _errorMessage = null;
    });

    final Result<List<ConversationListItemDto>> result =
        await _apiClient.listConversations();

    result.when(
      success: (List<ConversationListItemDto> conversations) {
        if (mounted) {
          setState(() {
            _conversations = conversations;
            _isLoading = false;
          });
        }
      },
      error: (ApiErrorInfo error) {
        if (mounted) {
          setState(() {
            _errorMessage = error.message;
            _isLoading = false;
          });
        }
      },
    );
  }

  List<ConversationListItemDto> get _filteredConversations {
    if (_conversations == null) return [];

    switch (_filterStatus) {
      case 'active':
        return _conversations!.where((c) => c.isActive).toList();
      case 'inactive':
        return _conversations!.where((c) => !c.isActive).toList();
      default:
        return _conversations!;
    }
  }

  @override
  Widget build(BuildContext context) {
    final ColorScheme colorScheme = Theme.of(context).colorScheme;

    return Container(
      padding: const EdgeInsets.all(24),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          // Header with actions
          _buildHeader(colorScheme),
          const SizedBox(height: 24),

          // Filter chips
          _buildFilterChips(colorScheme),
          const SizedBox(height: 24),

          // Conversations list
          Expanded(
            child: _buildConversationsList(colorScheme),
          ),
        ],
      ),
    );
  }

  Widget _buildHeader(ColorScheme colorScheme) {
    return Row(
      children: [
        Icon(
          Iconsax.messages_3,
          color: colorScheme.primary,
          size: 28,
        ),
        const SizedBox(width: 12),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                'Conversations',
                style: TextStyle(
                  fontSize: 24,
                  fontWeight: FontWeight.bold,
                  color: colorScheme.onSurface,
                ),
              ),
              Text(
                _conversations != null
                    ? '${_conversations!.length} total conversations'
                    : 'Loading...',
                style: TextStyle(
                  fontSize: 14,
                  color: colorScheme.onSurfaceVariant,
                ),
              ),
            ],
          ),
        ),
        IconButton(
          icon: Icon(Iconsax.refresh, color: colorScheme.primary),
          onPressed: _loadConversations,
          tooltip: 'Refresh conversations',
        ),
      ],
    );
  }

  Widget _buildFilterChips(ColorScheme colorScheme) {
    return Row(
      children: [
        _buildFilterChip('All', 'all', colorScheme),
        const SizedBox(width: 8),
        _buildFilterChip('Active', 'active', colorScheme),
        const SizedBox(width: 8),
        _buildFilterChip('Inactive', 'inactive', colorScheme),
      ],
    );
  }

  Widget _buildFilterChip(
    String label,
    String value,
    ColorScheme colorScheme,
  ) {
    final bool isSelected = _filterStatus == value;

    return FilterChip(
      label: Text(label),
      selected: isSelected,
      onSelected: (bool selected) {
        setState(() {
          _filterStatus = value;
        });
      },
      backgroundColor: colorScheme.surfaceContainerHigh,
      selectedColor: colorScheme.primaryContainer,
      labelStyle: TextStyle(
        color: isSelected
            ? colorScheme.onPrimaryContainer
            : colorScheme.onSurface,
      ),
    );
  }

  Widget _buildConversationsList(ColorScheme colorScheme) {
    if (_isLoading) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            CircularProgressIndicator(color: colorScheme.primary),
            const SizedBox(height: 16),
            Text(
              'Loading conversations...',
              style: TextStyle(color: colorScheme.onSurfaceVariant),
            ),
          ],
        ),
      );
    }

    if (_errorMessage != null) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              Iconsax.warning_2,
              size: 48,
              color: colorScheme.error,
            ),
            const SizedBox(height: 16),
            Text(
              'Failed to load conversations',
              style: TextStyle(
                fontSize: 18,
                fontWeight: FontWeight.bold,
                color: colorScheme.onSurface,
              ),
            ),
            const SizedBox(height: 8),
            Text(
              _errorMessage!,
              style: TextStyle(color: colorScheme.error),
              textAlign: TextAlign.center,
            ),
            const SizedBox(height: 24),
            ElevatedButton.icon(
              onPressed: _loadConversations,
              icon: const Icon(Iconsax.refresh),
              label: const Text('Retry'),
            ),
          ],
        ),
      );
    }

    final List<ConversationListItemDto> filtered = _filteredConversations;

    if (filtered.isEmpty) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              Iconsax.message_text,
              size: 64,
              color: colorScheme.onSurfaceVariant.withValues(alpha: 0.3),
            ),
            const SizedBox(height: 16),
            Text(
              'No conversations found',
              style: TextStyle(
                fontSize: 18,
                fontWeight: FontWeight.bold,
                color: colorScheme.onSurface,
              ),
            ),
            const SizedBox(height: 8),
            Text(
              _filterStatus == 'all'
                  ? 'Start a conversation to see it here'
                  : 'No $_filterStatus conversations',
              style: TextStyle(color: colorScheme.onSurfaceVariant),
            ),
          ],
        ),
      );
    }

    return ListView.builder(
      itemCount: filtered.length,
      itemBuilder: (BuildContext context, int index) {
        return FadeInUp(
          duration: Duration(milliseconds: 300 + (index * 50)),
          child: _buildConversationCard(filtered[index], colorScheme),
        );
      },
    );
  }

  Widget _buildConversationCard(
    ConversationListItemDto conversation,
    ColorScheme colorScheme,
  ) {
    return Card(
      margin: const EdgeInsets.only(bottom: 16),
      elevation: 0,
      color: colorScheme.surfaceContainerLow,
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(12),
        side: BorderSide(
          color: colorScheme.outline.withValues(alpha: 0.2),
          width: 1,
        ),
      ),
      child: InkWell(
        borderRadius: BorderRadius.circular(12),
        onTap: () {
          // TODO: Navigate to conversation detail
          ScaffoldMessenger.of(context).showSnackBar(
            SnackBar(
              content:
                  Text('View conversation: ${conversation.title} (not implemented)'),
            ),
          );
        },
        child: Padding(
          padding: const EdgeInsets.all(16),
          child: Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              // Icon
              Container(
                width: 48,
                height: 48,
                decoration: BoxDecoration(
                  color: conversation.isActive
                      ? colorScheme.primaryContainer
                      : colorScheme.surfaceContainerHighest,
                  borderRadius: BorderRadius.circular(8),
                ),
                child: Icon(
                  Iconsax.messages_3,
                  color: conversation.isActive
                      ? colorScheme.onPrimaryContainer
                      : colorScheme.onSurfaceVariant,
                  size: 24,
                ),
              ),
              const SizedBox(width: 16),

              // Content
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    // Title and status
                    Row(
                      children: [
                        Expanded(
                          child: Text(
                            conversation.title,
                            style: TextStyle(
                              fontSize: 16,
                              fontWeight: FontWeight.bold,
                              color: colorScheme.onSurface,
                            ),
                          ),
                        ),
                        Container(
                          padding: const EdgeInsets.symmetric(
                            horizontal: 8,
                            vertical: 4,
                          ),
                          decoration: BoxDecoration(
                            color: conversation.isActive
                                ? colorScheme.primaryContainer
                                : colorScheme.surfaceContainerHighest,
                            borderRadius: BorderRadius.circular(4),
                          ),
                          child: Text(
                            conversation.isActive ? 'Active' : 'Inactive',
                            style: TextStyle(
                              fontSize: 11,
                              fontWeight: FontWeight.bold,
                              color: conversation.isActive
                                  ? colorScheme.onPrimaryContainer
                                  : colorScheme.onSurfaceVariant,
                            ),
                          ),
                        ),
                      ],
                    ),
                    const SizedBox(height: 8),

                    // Summary
                    if (conversation.summary != null)
                      Text(
                        conversation.summary!,
                        style: TextStyle(
                          fontSize: 14,
                          color: colorScheme.onSurfaceVariant,
                        ),
                        maxLines: 2,
                        overflow: TextOverflow.ellipsis,
                      ),
                    const SizedBox(height: 12),

                    // Stats
                    Row(
                      children: [
                        _buildStat(
                          Iconsax.message_text,
                          '${conversation.messageCount}',
                          'messages',
                          colorScheme,
                        ),
                        const SizedBox(width: 16),
                        _buildStat(
                          Iconsax.flash_1,
                          '${conversation.executionCount}',
                          'executions',
                          colorScheme,
                        ),
                        const Spacer(),
                        Icon(
                          Iconsax.clock,
                          size: 14,
                          color: colorScheme.onSurfaceVariant,
                        ),
                        const SizedBox(width: 4),
                        Text(
                          timeago.format(conversation.lastMessageAt),
                          style: TextStyle(
                            fontSize: 12,
                            color: colorScheme.onSurfaceVariant,
                          ),
                        ),
                      ],
                    ),
                  ],
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildStat(
    IconData icon,
    String value,
    String label,
    ColorScheme colorScheme,
  ) {
    return Row(
      children: [
        Icon(
          icon,
          size: 16,
          color: colorScheme.primary,
        ),
        const SizedBox(width: 4),
        Text(
          value,
          style: TextStyle(
            fontSize: 14,
            fontWeight: FontWeight.bold,
            color: colorScheme.onSurface,
          ),
        ),
        const SizedBox(width: 2),
        Text(
          label,
          style: TextStyle(
            fontSize: 12,
            color: colorScheme.onSurfaceVariant,
          ),
        ),
      ],
    );
  }
}