import 'dart:math' as math;

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../../models/profile.model.dart';
import '../../models/programmer_project.model.dart';
import '../../models/programmer_task.model.dart';
import '../../providers/profile_provider.dart';
import '../../providers/programmer_projects_provider.dart';
import '../../providers/programmer_tasks_provider.dart';
import '../../widgets/quill_field.dart';

/// Shows the "New Programmer Task" dialog and, on success, navigates to the new
/// task's detail. Shared by the tasks list FAB and the project detail screen
/// (pass [initialProjectId] to pre-select a project).
Future<void> showCreateProgrammerTaskDialog(
  BuildContext context,
  WidgetRef ref, {
  String? initialProjectId,
}) async {
  final userId = ref.read(currentUserIdProvider);
  final profiles = ref.read(profilesProvider).valueOrNull ?? const <Profile>[];
  final eligible = profiles
      .where((p) => p.role == 'programmer' || p.role == 'admin')
      .toList()
    ..sort((a, b) => a.fullName.compareTo(b.fullName));
  final projectOptions =
      List<ProgrammerProject>.from(ref.read(activeProgrammerProjectsProvider));

  final titleCtrl = TextEditingController();
  final descQuill = quillControllerFromDelta(null);
  var category = ProgrammerTaskCategory.softwareDevelopment;
  var assigneeId = userId;
  var projectId = initialProjectId;

  final created = await showDialog<bool>(
    context: context,
    builder: (context) {
      return StatefulBuilder(
        builder: (context, setDialogState) {
          final dialogWidth =
              math.min(480.0, MediaQuery.of(context).size.width - 48);
          return AlertDialog(
            semanticLabel: 'New programmer task',
            title: const Text('New Programmer Task'),
            content: SizedBox(
              width: dialogWidth,
              child: SingleChildScrollView(
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  crossAxisAlignment: CrossAxisAlignment.stretch,
                  children: [
                  TextField(
                    controller: titleCtrl,
                    autofocus: true,
                    textCapitalization: TextCapitalization.sentences,
                    decoration: const InputDecoration(
                      labelText: 'Title',
                      hintText: 'What are you working on?',
                    ),
                  ),
                  const SizedBox(height: 12),
                  Align(
                    alignment: Alignment.centerLeft,
                    child: Text('Description (optional)',
                        style: Theme.of(context).textTheme.bodySmall),
                  ),
                  const SizedBox(height: 4),
                  QuillFieldEditor(
                    controller: descQuill,
                    placeholder: 'Describe the task…',
                    height: 140,
                  ),
                  const SizedBox(height: 12),
                  DropdownButtonFormField<String>(
                    initialValue: category,
                    decoration: const InputDecoration(labelText: 'Category'),
                    items: [
                      for (final c in ProgrammerTaskCategory.all)
                        DropdownMenuItem(value: c, child: Text(c)),
                    ],
                    onChanged: (v) =>
                        setDialogState(() => category = v ?? category),
                  ),
                  if (eligible.isNotEmpty) ...[
                    const SizedBox(height: 12),
                    DropdownButtonFormField<String>(
                      initialValue: assigneeId,
                      decoration: const InputDecoration(labelText: 'Assignee'),
                      items: [
                        for (final p in eligible)
                          DropdownMenuItem(
                            value: p.id,
                            child: Text(
                              p.id == userId ? '${p.fullName} (me)' : p.fullName,
                            ),
                          ),
                      ],
                      onChanged: (v) =>
                          setDialogState(() => assigneeId = v ?? assigneeId),
                    ),
                  ],
                  const SizedBox(height: 12),
                  DropdownButtonFormField<String?>(
                    initialValue: projectOptions.any((p) => p.id == projectId)
                        ? projectId
                        : null,
                    decoration:
                        const InputDecoration(labelText: 'Project (optional)'),
                    items: [
                      const DropdownMenuItem<String?>(
                          value: null, child: Text('No project')),
                      for (final p in projectOptions)
                        DropdownMenuItem<String?>(
                            value: p.id, child: Text(p.name)),
                    ],
                    onChanged: (v) => setDialogState(() => projectId = v),
                  ),
                  Align(
                    alignment: Alignment.centerLeft,
                    child: TextButton.icon(
                      onPressed: () async {
                        final proj = await _promptNewProject(context, ref);
                        if (proj != null) {
                          setDialogState(() {
                            projectOptions.add(proj);
                            projectId = proj.id;
                          });
                        }
                      },
                      icon: const Icon(Icons.add, size: 18),
                      label: const Text('New project'),
                    ),
                  ),
                  ],
                ),
              ),
            ),
            actions: [
              TextButton(
                onPressed: () => Navigator.of(context).pop(false),
                child: const Text('Cancel'),
              ),
              FilledButton(
                onPressed: () => Navigator.of(context).pop(true),
                child: const Text('Create'),
              ),
            ],
          );
        },
      );
    },
  );

  if (created != true) {
    titleCtrl.dispose();
    descQuill.dispose();
    return;
  }

  final title = titleCtrl.text.trim();
  titleCtrl.dispose();
  final description =
      quillPlainText(descQuill).isEmpty ? null : quillToDeltaJson(descQuill);
  descQuill.dispose();
  if (title.isEmpty) return;
  if (!context.mounted) return;

  final messenger = ScaffoldMessenger.of(context);
  try {
    final id = await ref.read(programmerTasksControllerProvider).createTask(
          title: title,
          category: category,
          description: description,
          assigneeId: assigneeId,
          projectId: projectId,
        );
    if (!context.mounted) return;
    context.go('/programmer-tasks/$id');
  } catch (e) {
    messenger.showSnackBar(SnackBar(content: Text('Could not create task: $e')));
  }
}

/// Prompts for a project name, creates it, and returns a lightweight model for
/// the picker (the realtime insert with the same id syncs shortly after).
Future<ProgrammerProject?> _promptNewProject(
  BuildContext context,
  WidgetRef ref,
) async {
  final messenger = ScaffoldMessenger.of(context);
  final nameCtrl = TextEditingController();
  final name = await showDialog<String>(
    context: context,
    builder: (context) => AlertDialog(
      semanticLabel: 'New project',
      title: const Text('New project'),
      content: TextField(
        controller: nameCtrl,
        autofocus: true,
        textCapitalization: TextCapitalization.words,
        decoration: const InputDecoration(labelText: 'Project name'),
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.of(context).pop(),
          child: const Text('Cancel'),
        ),
        FilledButton(
          onPressed: () => Navigator.of(context).pop(nameCtrl.text.trim()),
          child: const Text('Create'),
        ),
      ],
    ),
  );
  nameCtrl.dispose();
  if (name == null || name.isEmpty) return null;
  try {
    final id = await ref
        .read(programmerProjectsControllerProvider)
        .createProject(name: name);
    final now = DateTime.now().toUtc();
    return ProgrammerProject(
      id: id,
      name: name,
      status: ProgrammerProjectStatus.active,
      createdAt: now,
      updatedAt: now,
    );
  } catch (e) {
    messenger.showSnackBar(
      SnackBar(content: Text('Could not create project: $e')),
    );
    return null;
  }
}