import "package:go_router/go_router.dart";
import "package:provider/provider.dart";
import "package:shadcn_flutter/shadcn_flutter.dart";

import "../../../src/project_store.dart";
import "../../providers/chat_provider.dart";
import "../../providers/home_coordinator.dart";
import "../../providers/projects_provider.dart";
import "../../widgets/agents/agents_pane.dart";
import "../../widgets/chat/chat_box.dart";
import "../../widgets/chat/chat_view.dart";
import "../../widgets/common/footer_bar.dart";
import "../../widgets/sidebar/sidebar.dart";

class NewHomeScreen extends StatefulWidget {
  const NewHomeScreen({super.key});

  @override
  State<NewHomeScreen> createState() => _NewHomeScreenState();
}

class _NewHomeScreenState extends State<NewHomeScreen> {

  final ScrollController _chatScrollController = ScrollController();

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      context.read<HomeCoordinator>().addListener(_onCoordinatorChanged);
    });
  }

  @override
  void dispose() {
    context.read<HomeCoordinator>().removeListener(_onCoordinatorChanged);
    _chatScrollController.dispose();
    super.dispose();
  }

  void _onCoordinatorChanged() {
    final coordinator = context.read<HomeCoordinator>();
    final err = coordinator.error;
    if (err != null) {
      coordinator.clearError();
      _showError(err);
    }
  }

  Future<void> _showError(String message) {
    return showDialog<void>(
      context: context,
      builder: (dialogContext) => AlertDialog(
        title: const Text("Heads up"),
        content: Text(message),
        actions: [
          Button.primary(
            onPressed: () => Navigator.of(dialogContext).pop(),
            child: const Text("OK"),
          ),
        ],
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      child: Column(
        children: [
          Expanded(
            child: Row(
              children: [

                Sidebar(),

                Gap(1),

                VerticalDivider(),

                Expanded(
                  child: Stack(
                    children: [

                      _ChatArea(scrollController: _chatScrollController),

                      Positioned(
                        top: 0,
                        bottom: 0,
                        right: 0,
                        width: 12,
                        child: FullHeightScrollbar(controller: _chatScrollController),
                      ),

                    ],
                  ),
                ),

                AgentsPane(),

              ],
            ),
          ),

          FooterBar(),

        ],
      ),
    );
  }
}


class _ChatArea extends StatelessWidget {

  final ScrollController scrollController;

  const _ChatArea({required this.scrollController});

  @override
  Widget build(BuildContext context) {
    final chatProvider = context.watch<ChatProvider>();

    return Container(
      alignment: Alignment.center,
      padding: const EdgeInsets.all(16),
      child: ConstrainedBox(
        constraints: const BoxConstraints(maxWidth: 600),
        child: Column(
          children: [

            Expanded(
              child: chatProvider.messages.isEmpty
                ? _EmptyChatState()
                : ChatView(scrollController: scrollController),
            ),

            ChatBox(),

          ],
        ),
      ),
    );
  }
}


class _EmptyChatState extends StatelessWidget {

  const _EmptyChatState();

  @override
  Widget build(BuildContext context) {
    final projectsProvider = context.watch<ProjectsProvider>();
    final projects = projectsProvider.projects;
    final selected = projectsProvider.selectedProject;
    final coordinator = context.read<HomeCoordinator>();

    return Center(
      child: Padding(
        padding: const EdgeInsets.all(24),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [

            const Icon(LucideIcons.messagesSquare, size: 28),
            const Gap(16),
            Text(
              "Ask the agency anything",
              style: const TextStyle(fontSize: 22, fontWeight: FontWeight.w700),
              textAlign: TextAlign.center,
            ),
            const Gap(8),
            Text(
              "Select a project and thread from the sidebar, or start a new chat.",
              textAlign: TextAlign.center,
            ).textSmall.muted,

            const Gap(24),

            Select<ProjectRecord>(
              itemBuilder: (context, item) => Text(item.name),
              popup: SelectPopup.builder(
                searchPlaceholder: const Text("Search projects"),
                builder: (context, searchQuery) {
                  final filtered = searchQuery == null || searchQuery.isEmpty
                      ? projects
                      : projects.where((p) =>
                          p.name.toLowerCase().contains(searchQuery.toLowerCase()) ||
                          p.workingDirectory.toLowerCase().contains(searchQuery.toLowerCase())
                        ).toList();

                  return SelectItemList(
                    children: [
                      for (final project in filtered)
                        SelectItemButton(
                          value: project,
                          child: Column(
                            crossAxisAlignment: CrossAxisAlignment.start,
                            children: [
                              Text(project.name),
                              Text(project.workingDirectory).textSmall.muted,
                            ],
                          ),
                        ),
                    ],
                  );
                },
              ),
              onChanged: (project) {
                if (project != null) coordinator.selectProject(project);
              },
              constraints: const BoxConstraints(minWidth: 240),
              value: selected,
              placeholder: const Text("Select a project"),
            ),

          ],
        ),
      ),
    );
  }
}


abstract class HomeScreenRoute {
  static const path = '/';
  static const name = 'home';

  static GoRoute get route => GoRoute(
    path: path,
    name: name,
    builder: (context, state) => const NewHomeScreen(),
  );
}