import 'package:ac_web/Api/Dtos/AgentTaskDto.dart';
import 'package:flutter/material.dart';

/// Card that shows a single task of an agent.
///
/// Collapsed it only shows the title, the start time and the newest status
/// line. Expanded it lists every status update the agent reported so far.
class AgentTaskCard extends StatelessWidget {
  const AgentTaskCard({super.key, required this.task, this.initiallyExpanded = false});

  final AgentTaskDto task;

  /// Expands the status update history right away, e.g. for the newest task.
  final bool initiallyExpanded;

  @override
  Widget build(BuildContext context) {

    final ThemeData theme = Theme.of(context);

    return Card(
      shape: RoundedRectangleBorder(borderRadius: BorderRadiusGeometry.circular(12)),
      shadowColor: Colors.white,
      color: Colors.black38,
      margin: EdgeInsetsGeometry.fromLTRB(0, 8, 0, 8),
      clipBehavior: Clip.antiAlias,
      child: ExpansionTile(
        initiallyExpanded: initiallyExpanded,
        shape: const Border(),
        collapsedShape: const Border(),
        leading: CircleAvatar(
          backgroundColor: theme.colorScheme.inversePrimary,
          child: Icon(Icons.task_alt, color: theme.colorScheme.onSurface),
        ),
        title: Text(
          task.title.isEmpty ? "Untitled Task" : task.title,
          style: theme.textTheme.titleMedium,
        ),
        subtitle: Text(
          _subtitle(),
          style: theme.textTheme.bodySmall,
        ),
        childrenPadding: EdgeInsetsGeometry.fromLTRB(16, 0, 16, 16),
        expandedCrossAxisAlignment: CrossAxisAlignment.start,
        children: [
          if (!task.hasStatusUpdates)
            Text(
              "This task has no status updates yet.",
              style: theme.textTheme.bodyMedium,
            )
          else
            for (int i = 0; i < task.statusUpdates.length; i++)
              _buildStatusUpdate(
                context,
                task.statusUpdates[i],
                isLast: i == task.statusUpdates.length - 1,
              ),
        ],
      ),
    );
  }

  /// Start time and, when the agent already reported one, the newest status.
  String _subtitle() {

    final String? latest = task.latestStatus;
    final String started = task.startTime == null
        ? "Start unknown"
        : "Started ${_formatTimestamp(task.startTime!.toLocal())}";

    if (latest == null || latest.isEmpty) {
      return started;
    }
    return "$started  •  $latest";
  }

  /// One entry of the status update history, drawn as a small timeline.
  Widget _buildStatusUpdate(BuildContext context, String update, {required bool isLast}) {

    final ThemeData theme = Theme.of(context);

    return IntrinsicHeight(
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        spacing: 12,
        children: [
          // Dot of this entry plus the line down to the following one.
          Column(
            children: [
              Container(
                width: 10,
                height: 10,
                margin: EdgeInsetsGeometry.only(top: 6),
                decoration: BoxDecoration(
                  color: isLast ? theme.colorScheme.primary : theme.colorScheme.outline,
                  shape: BoxShape.circle,
                ),
              ),
              if (!isLast)
                Expanded(
                  child: Container(
                    width: 2,
                    color: theme.colorScheme.outline,
                  ),
                ),
            ],
          ),
          Expanded(
            child: Padding(
              padding: EdgeInsetsGeometry.only(bottom: isLast ? 0 : 12),
              child: SelectableText(
                update,
                style: isLast
                    ? theme.textTheme.bodyMedium
                    : theme.textTheme.bodyMedium?.copyWith(color: theme.colorScheme.onSurfaceVariant),
              ),
            ),
          ),
        ],
      ),
    );
  }

  /// e.g. "15.08.2025 09:05"
  String _formatTimestamp(DateTime timestamp) {

    final String day = timestamp.day.toString().padLeft(2, '0');
    final String month = timestamp.month.toString().padLeft(2, '0');
    final String hour = timestamp.hour.toString().padLeft(2, '0');
    final String minute = timestamp.minute.toString().padLeft(2, '0');

    return "$day.$month.${timestamp.year} $hour:$minute";
  }
}