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';

/// Executions dashboard page
///
/// Displays all agent executions with filtering by status, metrics, and details.
/// Integrates with backend CQRS API for execution monitoring and analysis.
class ExecutionsPage extends StatefulWidget {
  const ExecutionsPage({super.key});

  @override
  State<ExecutionsPage> createState() => _ExecutionsPageState();
}

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

  List<ExecutionListItemDto>? _executions;
  bool _isLoading = true;
  String? _errorMessage;
  ExecutionStatus? _filterStatus; // null = all, or specific status

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

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

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

    final Result<List<ExecutionListItemDto>> result = _filterStatus == null
        ? await _apiClient.listExecutions()
        : await _apiClient.listExecutionsByStatus(_filterStatus!);

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

  Map<String, int> get _statusCounts {
    if (_executions == null) return {};

    final Map<String, int> counts = {};
    for (final ExecutionListItemDto exec in _executions!) {
      counts[exec.status.value] = (counts[exec.status.value] ?? 0) + 1;
    }
    return counts;
  }

  double get _totalCost {
    if (_executions == null) return 0.0;

    return _executions!.fold<double>(
      0.0,
      (double sum, ExecutionListItemDto exec) =>
          sum + (exec.estimatedCost ?? 0.0),
    );
  }

  int get _totalTokens {
    if (_executions == null) return 0;

    return _executions!.fold<int>(
      0,
      (int sum, ExecutionListItemDto exec) =>
          sum + (exec.inputTokens ?? 0) + (exec.outputTokens ?? 0),
    );
  }

  @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),

          // Metrics cards
          _buildMetricsCards(colorScheme),
          const SizedBox(height: 24),

          // Status filter chips
          _buildStatusFilters(colorScheme),
          const SizedBox(height: 24),

          // Executions list
          Expanded(
            child: _buildExecutionsList(colorScheme),
          ),
        ],
      ),
    );
  }

  Widget _buildHeader(ColorScheme colorScheme) {
    return Row(
      children: [
        Icon(
          Iconsax.flash_1,
          color: colorScheme.primary,
          size: 28,
        ),
        const SizedBox(width: 12),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                'Agent Executions',
                style: TextStyle(
                  fontSize: 24,
                  fontWeight: FontWeight.bold,
                  color: colorScheme.onSurface,
                ),
              ),
              Text(
                _executions != null
                    ? '${_executions!.length} total executions'
                    : 'Loading...',
                style: TextStyle(
                  fontSize: 14,
                  color: colorScheme.onSurfaceVariant,
                ),
              ),
            ],
          ),
        ),
        IconButton(
          icon: Icon(Iconsax.refresh, color: colorScheme.primary),
          onPressed: _loadExecutions,
          tooltip: 'Refresh executions',
        ),
      ],
    );
  }

  Widget _buildMetricsCards(ColorScheme colorScheme) {
    return Row(
      children: [
        Expanded(
          child: _buildMetricCard(
            'Total Cost',
            '\$${_totalCost.toStringAsFixed(4)}',
            Iconsax.dollar_circle,
            colorScheme.primaryContainer,
            colorScheme.onPrimaryContainer,
          ),
        ),
        const SizedBox(width: 16),
        Expanded(
          child: _buildMetricCard(
            'Total Tokens',
            _totalTokens.toString(),
            Iconsax.cpu,
            colorScheme.secondaryContainer,
            colorScheme.onSecondaryContainer,
          ),
        ),
        const SizedBox(width: 16),
        Expanded(
          child: _buildMetricCard(
            'Avg Messages',
            _executions != null && _executions!.isNotEmpty
                ? (_executions!.fold<int>(
                          0,
                          (int sum, ExecutionListItemDto exec) =>
                              sum + exec.messageCount,
                        ) /
                        _executions!.length)
                    .toStringAsFixed(1)
                : '0',
            Iconsax.message_text,
            colorScheme.tertiaryContainer,
            colorScheme.onTertiaryContainer,
          ),
        ),
      ],
    );
  }

  Widget _buildMetricCard(
    String label,
    String value,
    IconData icon,
    Color backgroundColor,
    Color textColor,
  ) {
    return Container(
      padding: const EdgeInsets.all(16),
      decoration: BoxDecoration(
        color: backgroundColor,
        borderRadius: BorderRadius.circular(12),
      ),
      child: Row(
        children: [
          Icon(icon, color: textColor, size: 32),
          const SizedBox(width: 12),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  label,
                  style: TextStyle(
                    fontSize: 12,
                    color: textColor.withValues(alpha: 0.8),
                  ),
                ),
                Text(
                  value,
                  style: TextStyle(
                    fontSize: 20,
                    fontWeight: FontWeight.bold,
                    color: textColor,
                  ),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildStatusFilters(ColorScheme colorScheme) {
    return SingleChildScrollView(
      scrollDirection: Axis.horizontal,
      child: Row(
        children: [
          _buildStatusChip('All', null, colorScheme),
          const SizedBox(width: 8),
          _buildStatusChip(
            'Pending',
            ExecutionStatus.pending,
            colorScheme,
          ),
          const SizedBox(width: 8),
          _buildStatusChip(
            'Running',
            ExecutionStatus.running,
            colorScheme,
          ),
          const SizedBox(width: 8),
          _buildStatusChip(
            'Completed',
            ExecutionStatus.completed,
            colorScheme,
          ),
          const SizedBox(width: 8),
          _buildStatusChip(
            'Failed',
            ExecutionStatus.failed,
            colorScheme,
          ),
          const SizedBox(width: 8),
          _buildStatusChip(
            'Cancelled',
            ExecutionStatus.cancelled,
            colorScheme,
          ),
        ],
      ),
    );
  }

  Widget _buildStatusChip(
    String label,
    ExecutionStatus? status,
    ColorScheme colorScheme,
  ) {
    final bool isSelected = _filterStatus == status;
    final int count =
        status == null ? (_executions?.length ?? 0) : (_statusCounts[status.value] ?? 0);

    return FilterChip(
      label: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          Text(label),
          if (count > 0) ...[
            const SizedBox(width: 6),
            Container(
              padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
              decoration: BoxDecoration(
                color: isSelected
                    ? colorScheme.onPrimaryContainer.withValues(alpha: 0.2)
                    : colorScheme.onSurface.withValues(alpha: 0.1),
                borderRadius: BorderRadius.circular(10),
              ),
              child: Text(
                count.toString(),
                style: TextStyle(
                  fontSize: 11,
                  fontWeight: FontWeight.bold,
                  color: isSelected
                      ? colorScheme.onPrimaryContainer
                      : colorScheme.onSurface,
                ),
              ),
            ),
          ],
        ],
      ),
      selected: isSelected,
      onSelected: (bool selected) {
        setState(() {
          _filterStatus = status;
        });
        _loadExecutions();
      },
      backgroundColor: colorScheme.surfaceContainerHigh,
      selectedColor: colorScheme.primaryContainer,
      labelStyle: TextStyle(
        color: isSelected
            ? colorScheme.onPrimaryContainer
            : colorScheme.onSurface,
      ),
    );
  }

  Widget _buildExecutionsList(ColorScheme colorScheme) {
    if (_isLoading) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            CircularProgressIndicator(color: colorScheme.primary),
            const SizedBox(height: 16),
            Text(
              'Loading executions...',
              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 executions',
              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: _loadExecutions,
              icon: const Icon(Iconsax.refresh),
              label: const Text('Retry'),
            ),
          ],
        ),
      );
    }

    if (_executions == null || _executions!.isEmpty) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              Iconsax.flash_1,
              size: 64,
              color: colorScheme.onSurfaceVariant.withValues(alpha: 0.3),
            ),
            const SizedBox(height: 16),
            Text(
              'No executions found',
              style: TextStyle(
                fontSize: 18,
                fontWeight: FontWeight.bold,
                color: colorScheme.onSurface,
              ),
            ),
            const SizedBox(height: 8),
            Text(
              _filterStatus == null
                  ? 'Start an agent execution to see it here'
                  : 'No ${_filterStatus!.value.toLowerCase()} executions',
              style: TextStyle(color: colorScheme.onSurfaceVariant),
            ),
          ],
        ),
      );
    }

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

  Widget _buildExecutionCard(
    ExecutionListItemDto execution,
    ColorScheme colorScheme,
  ) {
    final Color statusColor = _getStatusColor(execution.status, 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 execution detail
          ScaffoldMessenger.of(context).showSnackBar(
            SnackBar(
              content: Text('View execution details (not implemented)'),
            ),
          );
        },
        child: Padding(
          padding: const EdgeInsets.all(16),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              // Header row
              Row(
                children: [
                  // Status indicator
                  Container(
                    width: 12,
                    height: 12,
                    decoration: BoxDecoration(
                      color: statusColor,
                      shape: BoxShape.circle,
                    ),
                  ),
                  const SizedBox(width: 12),

                  // Agent name
                  Expanded(
                    child: Text(
                      execution.agentName,
                      style: TextStyle(
                        fontSize: 16,
                        fontWeight: FontWeight.bold,
                        color: colorScheme.onSurface,
                      ),
                    ),
                  ),

                  // Status badge
                  Container(
                    padding: const EdgeInsets.symmetric(
                      horizontal: 8,
                      vertical: 4,
                    ),
                    decoration: BoxDecoration(
                      color: statusColor.withValues(alpha: 0.2),
                      borderRadius: BorderRadius.circular(4),
                    ),
                    child: Text(
                      execution.status.value,
                      style: TextStyle(
                        fontSize: 11,
                        fontWeight: FontWeight.bold,
                        color: statusColor,
                      ),
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 12),

              // User prompt
              Text(
                execution.userPrompt,
                style: TextStyle(
                  fontSize: 14,
                  color: colorScheme.onSurfaceVariant,
                ),
                maxLines: 2,
                overflow: TextOverflow.ellipsis,
              ),

              // Error message if failed
              if (execution.errorMessage != null) ...[
                const SizedBox(height: 8),
                Container(
                  padding: const EdgeInsets.all(8),
                  decoration: BoxDecoration(
                    color: colorScheme.errorContainer,
                    borderRadius: BorderRadius.circular(6),
                  ),
                  child: Row(
                    children: [
                      Icon(
                        Iconsax.warning_2,
                        size: 16,
                        color: colorScheme.onErrorContainer,
                      ),
                      const SizedBox(width: 8),
                      Expanded(
                        child: Text(
                          execution.errorMessage!,
                          style: TextStyle(
                            fontSize: 12,
                            color: colorScheme.onErrorContainer,
                          ),
                          maxLines: 2,
                          overflow: TextOverflow.ellipsis,
                        ),
                      ),
                    ],
                  ),
                ),
              ],
              const SizedBox(height: 12),

              // Stats row
              Row(
                children: [
                  _buildExecutionStat(
                    Iconsax.message_text,
                    '${execution.messageCount}',
                    colorScheme,
                  ),
                  if (execution.inputTokens != null &&
                      execution.outputTokens != null) ...[
                    const SizedBox(width: 16),
                    _buildExecutionStat(
                      Iconsax.cpu,
                      '${execution.inputTokens! + execution.outputTokens!}',
                      colorScheme,
                    ),
                  ],
                  if (execution.estimatedCost != null) ...[
                    const SizedBox(width: 16),
                    _buildExecutionStat(
                      Iconsax.dollar_circle,
                      '\$${execution.estimatedCost!.toStringAsFixed(4)}',
                      colorScheme,
                    ),
                  ],
                  const Spacer(),
                  Icon(
                    Iconsax.clock,
                    size: 14,
                    color: colorScheme.onSurfaceVariant,
                  ),
                  const SizedBox(width: 4),
                  Text(
                    timeago.format(execution.startedAt),
                    style: TextStyle(
                      fontSize: 12,
                      color: colorScheme.onSurfaceVariant,
                    ),
                  ),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildExecutionStat(
    IconData icon,
    String value,
    ColorScheme colorScheme,
  ) {
    return Row(
      children: [
        Icon(
          icon,
          size: 16,
          color: colorScheme.primary,
        ),
        const SizedBox(width: 4),
        Text(
          value,
          style: TextStyle(
            fontSize: 13,
            fontWeight: FontWeight.bold,
            color: colorScheme.onSurface,
          ),
        ),
      ],
    );
  }

  Color _getStatusColor(ExecutionStatus status, ColorScheme colorScheme) {
    switch (status) {
      case ExecutionStatus.pending:
        return colorScheme.tertiary;
      case ExecutionStatus.running:
        return colorScheme.primary;
      case ExecutionStatus.completed:
        return Colors.green;
      case ExecutionStatus.failed:
        return colorScheme.error;
      case ExecutionStatus.cancelled:
        return colorScheme.onSurfaceVariant;
    }
  }
}