/// Renders the Backlog Pane widget for the FocusFlow Flutter UI.
library;

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

import '../controllers/scheduler_command_controller.dart';
import '../controllers/scheduler_read_controller.dart';
import 'read_state_view.dart';
import 'schedule_components.dart';

class BacklogPane extends StatelessWidget {
  const BacklogPane({
    required this.controller,
    this.commandController,
    super.key,
  });

  final UiReadController<BacklogQueryResult> controller;
  final SchedulerCommandController? commandController;

  @override
  Widget build(BuildContext context) {
    return ReadStateView<BacklogQueryResult>(
      controller: controller,
      title: 'Backlog',
      emptyTitle: 'Backlog is clear',
      emptyMessage: 'Captured tasks will appear here when they need planning.',
      dataBuilder: (context, result) =>
          BacklogContent(result: result, commandController: commandController),
    );
  }
}

class BacklogContent extends StatelessWidget {
  const BacklogContent({
    required this.result,
    this.commandController,
    super.key,
  });

  final BacklogQueryResult result;
  final SchedulerCommandController? commandController;

  @override
  Widget build(BuildContext context) {
    return ListView(
      padding: const EdgeInsets.all(16),
      children: [
        Text('Backlog', style: Theme.of(context).textTheme.headlineMedium),
        const SizedBox(height: 12),
        if (commandController != null) ...[
          QuickCaptureForm(commandController: commandController!),
          const SizedBox(height: 12),
          CommandStatusBanner(controller: commandController!),
          const SizedBox(height: 12),
        ],
        for (final item in result.items)
          BacklogRow(
            item: item,
            onSchedule: commandController == null
                ? null
                : (durationMinutes) {
                    return commandController!.scheduleBacklogItem(
                      taskId: item.task.id,
                      durationMinutes: durationMinutes,
                      expectedUpdatedAt: item.task.updatedAt,
                    );
                  },
          ),
      ],
    );
  }
}

class QuickCaptureForm extends StatefulWidget {
  const QuickCaptureForm({required this.commandController, super.key});

  final SchedulerCommandController commandController;

  @override
  State<QuickCaptureForm> createState() => _QuickCaptureFormState();
}

class _QuickCaptureFormState extends State<QuickCaptureForm> {
  final titleController = TextEditingController();

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

  @override
  Widget build(BuildContext context) {
    return Row(
      children: [
        Expanded(
          child: TextField(
            key: const ValueKey('quick-capture-title'),
            controller: titleController,
            decoration: const InputDecoration(labelText: 'Quick capture'),
            textInputAction: TextInputAction.done,
          ),
        ),
        const SizedBox(width: 8),
        FilledButton.icon(
          onPressed: () async {
            final title = titleController.text.trim();
            if (title.isEmpty) {
              return;
            }
            await widget.commandController.quickCaptureToBacklog(title);
            titleController.clear();
          },
          icon: const Icon(Icons.add),
          label: const Text('Capture'),
        ),
      ],
    );
  }
}

class CommandStatusBanner extends StatelessWidget {
  const CommandStatusBanner({required this.controller, super.key});

  final SchedulerCommandController controller;

  @override
  Widget build(BuildContext context) {
    return AnimatedBuilder(
      animation: controller,
      builder: (context, _) {
        return switch (controller.state) {
          SchedulerCommandIdle() => const SizedBox.shrink(),
          SchedulerCommandRunning(label: final label) => Text(label),
          SchedulerCommandSuccess(message: final message) => Text(message),
          SchedulerCommandFailure(failure: final failure, error: final error) =>
            Text(
              'Command issue: '
              '${failure?.detailCode ?? failure?.code.name ?? error ?? 'unexpected'}',
            ),
        };
      },
    );
  }
}