// SPDX-FileCopyrightText: 2026 FocusFlow contributors
// SPDX-License-Identifier: AGPL-3.0-only

/// Renders the Schedule Components widget for the FocusFlow Flutter UI.
library;

import 'package:flutter/material.dart';
import 'package:scheduler_core/scheduler_core.dart';

import '../theme/scheduler_visual_tokens.dart';

/// Compact summary panel for timeline items.
class CompactPanel extends StatelessWidget {
  /// Creates a compact panel for [items].
  const CompactPanel({required this.items, super.key});

  /// Timeline items to display in compact form.
  final List<TodayTimelineItem> items;

  /// Builds the widget subtree for this component.
  /// The method translates the current widget configuration and state into Flutter UI without mutating scheduler domain data.
  @override
  Widget build(BuildContext context) {
    if (items.isEmpty) {
      return const SizedBox.shrink();
    }
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text('Compact', style: Theme.of(context).textTheme.titleMedium),
        const SizedBox(height: 8),
        for (final item in items) TimelineRow(item: item),
        const SizedBox(height: 20),
      ],
    );
  }
}

/// Card row for a single Today timeline item.
class TimelineRow extends StatelessWidget {
  /// Creates a timeline row.
  const TimelineRow({required this.item, this.onDone, super.key});

  /// Timeline item to render.
  final TodayTimelineItem item;

  /// Optional completion callback for eligible tasks.
  final Future<void> Function()? onDone;

  /// Builds the widget subtree for this component.
  /// The method translates the current widget configuration and state into Flutter UI without mutating scheduler domain data.
  @override
  Widget build(BuildContext context) {
    final scheme = Theme.of(context).colorScheme;
    final projectColor = SchedulerVisualTokens.projectColor(
      item.projectColorToken,
    );
    return Card(
      margin: const EdgeInsets.only(bottom: 8),
      color: SchedulerVisualTokens.backgroundColor(
        item.item.backgroundToken,
        scheme,
      ),
      shape: RoundedRectangleBorder(
        side: BorderSide(color: projectColor, width: 2),
        borderRadius: BorderRadius.circular(8),
      ),
      child: ListTile(
        leading: Icon(
          SchedulerVisualTokens.taskIcon(item.taskType),
          color: projectColor,
        ),
        title: Text(item.item.displayTitle),
        subtitle: Text(timeText(item.item)),
        trailing: Wrap(
          spacing: 6,
          children: [
            Icon(
              SchedulerVisualTokens.rewardIcon(item.item.rewardIconToken),
              size: 18,
            ),
            Icon(
              SchedulerVisualTokens.difficultyIcon(
                item.item.difficultyIconToken,
              ),
              size: 18,
            ),
            if (onDone != null)
              IconButton(
                tooltip: 'Done',
                onPressed: () {
                  onDone!();
                },
                icon: const Icon(Icons.check_circle_outline),
              ),
          ],
        ),
      ),
    );
  }
}

/// Backlog row with optional scheduling controls.
class BacklogRow extends StatefulWidget {
  /// Creates a backlog row.
  const BacklogRow({required this.item, this.onSchedule, super.key});

  /// Backlog item to render.
  final BacklogItemReadModel item;

  /// Optional callback that schedules the item for a duration in minutes.
  final Future<void> Function(int durationMinutes)? onSchedule;

  /// Creates the mutable state object used by this stateful widget.
  /// Flutter calls this once for each mounted widget instance before lifecycle callbacks and builds begin.
  @override
  State<BacklogRow> createState() => _BacklogRowState();
}

/// Private implementation type for `_BacklogRowState` in this library.
/// It keeps supporting state and behavior scoped to the owning file so the public API stays focused on the scheduler concepts that callers use directly.
class _BacklogRowState extends State<BacklogRow> {
  /// Stores the `durationController` value for this object.
  /// This field is part of the explicit state that downstream scheduling, persistence, or UI code reads when composing behavior.
  final durationController = TextEditingController();

  /// Releases resources owned by this object before it leaves the tree.
  /// Controllers, listeners, and other disposable collaborators should be cleaned up here to avoid stale callbacks.
  @override
  void dispose() {
    durationController.dispose();
    super.dispose();
  }

  /// Builds the widget subtree for this component.
  /// The method translates the current widget configuration and state into Flutter UI without mutating scheduler domain data.
  @override
  Widget build(BuildContext context) {
    final scheme = Theme.of(context).colorScheme;
    return Card(
      margin: const EdgeInsets.only(bottom: 8),
      child: ListTile(
        leading: StalenessMarker(marker: widget.item.stalenessMarker),
        title: Text(widget.item.task.title),
        subtitle: Text(
          'Priority ${widget.item.task.priority?.name ?? 'unset'}',
        ),
        iconColor: SchedulerVisualTokens.stalenessColor(
          widget.item.stalenessMarker,
          scheme,
        ),
        trailing: widget.onSchedule == null
            ? null
            : SizedBox(
                width: 168,
                child: Row(
                  children: [
                    Expanded(
                      child: TextField(
                        key: ValueKey('duration-${widget.item.task.id}'),
                        controller: durationController,
                        decoration: const InputDecoration(labelText: 'Min'),
                        keyboardType: TextInputType.number,
                      ),
                    ),
                    IconButton(
                      tooltip: 'Schedule',
                      onPressed: () {
                        final duration = int.tryParse(
                          durationController.text.trim(),
                        );
                        if (duration == null) {
                          return;
                        }
                        widget.onSchedule!(duration);
                      },
                      icon: const Icon(Icons.event_available),
                    ),
                  ],
                ),
              ),
      ),
    );
  }
}

/// Icon marker for backlog item staleness.
class StalenessMarker extends StatelessWidget {
  /// Creates a staleness marker.
  const StalenessMarker({required this.marker, super.key});

  /// Staleness marker value to render.
  final BacklogStalenessMarker marker;

  /// Builds the widget subtree for this component.
  /// The method translates the current widget configuration and state into Flutter UI without mutating scheduler domain data.
  @override
  Widget build(BuildContext context) {
    return Icon(
      SchedulerVisualTokens.stalenessIcon(marker),
      semanticLabel: 'Staleness ${marker.name}',
    );
  }
}

/// Notice banner for pending Today-state messages.
class NoticeBanner extends StatelessWidget {
  /// Creates a notice banner.
  const NoticeBanner({required this.message, super.key});

  /// Notice message to display.
  final String message;

  /// Builds the widget subtree for this component.
  /// The method translates the current widget configuration and state into Flutter UI without mutating scheduler domain data.
  @override
  Widget build(BuildContext context) {
    return Container(
      margin: const EdgeInsets.only(bottom: 12),
      padding: const EdgeInsets.all(12),
      decoration: BoxDecoration(
        color: Theme.of(context).colorScheme.secondaryContainer,
        borderRadius: BorderRadius.circular(8),
      ),
      child: Text(message),
    );
  }
}

/// Formats a scheduler timeline item as display-ready time text.
String timeText(TimelineItem item) {
  final start = item.start;
  final end = item.end;
  if (start == null || end == null) {
    return '${item.durationMinutes ?? 0} min';
  }
  return '${_clockText(start)}-${_clockText(end)}';
}

/// Top-level helper that performs the `_clockText` operation for this file.
/// Keeping the helper private makes the surrounding flow easier to read while preventing unrelated libraries from depending on implementation detail.
String _clockText(DateTime value) {
  final hour = value.hour.toString().padLeft(2, '0');
  final minute = value.minute.toString().padLeft(2, '0');
  return '$hour:$minute';
}