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

import '../../domain/mission/drone_profile.dart';
import '../../services/database/mission_repository.dart';
import '../../services/sharing/drone_share_codec.dart';
import '../../services/sharing/mission_share_codec.dart';
import '../providers/active_drone_profile_provider.dart';
import '../providers/database_provider.dart';
import '../providers/mission_meta_provider.dart';
import '../providers/sharing_provider.dart';
import '../providers/wind_provider.dart';
import 'drone_profile_editor.dart';

enum _ManagementTab { missions, drones }

/// Vollbild-Verwaltungsmenue fuer Missionen und Drohnenprofile (Doku 3.5/
/// 3.6/7.1/7.3), per Tabs umschaltbar - analog #missionsPanel im HTML-
/// Demonstrator. Erreichbar ueber die Mission-/Drone-Chips in der
/// Fusszeile, die jeweils mit dem passenden Starttab oeffnen.
class MissionsDronesPanel extends ConsumerStatefulWidget {
  const MissionsDronesPanel.missions({super.key}) : _initialTab = _ManagementTab.missions;
  const MissionsDronesPanel.drones({super.key}) : _initialTab = _ManagementTab.drones;

  final _ManagementTab _initialTab;

  @override
  ConsumerState<MissionsDronesPanel> createState() => _MissionsDronesPanelState();
}

class _MissionsDronesPanelState extends ConsumerState<MissionsDronesPanel> {
  late _ManagementTab _tab = widget._initialTab;

  @override
  Widget build(BuildContext context) {
    return Material(
      color: const Color(0xEB080808),
      child: SafeArea(
        child: Column(
          children: [
            Padding(
              padding: const EdgeInsets.fromLTRB(16, 12, 8, 12),
              child: Row(
                children: [
                  const Expanded(
                    child: Text(
                      'Missions & Drones',
                      style: TextStyle(
                        color: Colors.white,
                        fontSize: 20,
                        fontWeight: FontWeight.w700,
                      ),
                    ),
                  ),
                  IconButton(
                    onPressed: () => Navigator.of(context).pop(),
                    icon: const Icon(Icons.close, color: Colors.white),
                  ),
                ],
              ),
            ),
            Row(
              children: [
                _tabButton('Missions', _ManagementTab.missions),
                _tabButton('Drones', _ManagementTab.drones),
              ],
            ),
            const Divider(color: Colors.white24, height: 1),
            Expanded(
              child: switch (_tab) {
                _ManagementTab.missions => _missionsTab(),
                _ManagementTab.drones => _dronesTab(),
              },
            ),
          ],
        ),
      ),
    );
  }

  Widget _tabButton(String label, _ManagementTab tab) {
    final active = _tab == tab;
    return Expanded(
      child: InkWell(
        onTap: () => setState(() => _tab = tab),
        child: Container(
          padding: const EdgeInsets.symmetric(vertical: 10),
          decoration: BoxDecoration(
            border: Border(
              bottom: BorderSide(
                color: active ? const Color(0xFF4D9DFF) : Colors.transparent,
                width: 2,
              ),
            ),
          ),
          child: Text(
            label,
            textAlign: TextAlign.center,
            style: TextStyle(
              color: active ? Colors.white : Colors.white60,
              fontWeight: FontWeight.w600,
              fontSize: 14,
            ),
          ),
        ),
      ),
    );
  }

  // --- Missions ---

  Widget _missionsTab() {
    final summaries = ref.watch(missionSummariesProvider);
    final currentId = ref.watch(currentMissionMetaProvider).id;

    return Column(
      children: [
        Padding(
          padding: const EdgeInsets.all(12),
          child: Row(
            children: [
              _ToolbarButton(
                icon: Icons.add,
                label: 'New mission',
                onTap: () async {
                  await ref.read(currentMissionMetaProvider.notifier).startNew();
                  if (mounted) Navigator.of(context).pop();
                },
              ),
              const SizedBox(width: 8),
              _ToolbarButton(
                icon: Icons.file_upload_outlined,
                label: 'Import',
                onTap: _importMission,
              ),
            ],
          ),
        ),
        Expanded(
          child: summaries.when(
            data: (missions) {
              if (missions.isEmpty) {
                return const Center(
                  child: Text('No saved missions yet',
                      style: TextStyle(color: Colors.white60, fontSize: 15)),
                );
              }
              final sorted = [...missions]
                ..sort((a, b) => b.updatedAt.compareTo(a.updatedAt));
              return ListView.builder(
                padding: const EdgeInsets.symmetric(horizontal: 16),
                itemCount: sorted.length,
                itemBuilder: (context, index) =>
                    _missionRow(sorted[index], isActive: sorted[index].id == currentId),
              );
            },
            loading: () => const Center(
              child: CircularProgressIndicator(color: Color(0xFF4D9DFF)),
            ),
            error: (err, st) => Center(
              child: Text('Error loading missions: $err',
                  style: const TextStyle(color: Color(0xFFE2574A))),
            ),
          ),
        ),
      ],
    );
  }

  Widget _missionRow(MissionSummary m, {required bool isActive}) {
    return GestureDetector(
      onTap: () async {
        await ref.read(currentMissionMetaProvider.notifier).loadMission(m.id);
        await ref.read(headerWindProvider.notifier).refresh();
        if (mounted) Navigator.of(context).pop();
      },
      child: Container(
        margin: const EdgeInsets.symmetric(vertical: 4),
        padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 10),
        decoration: BoxDecoration(
          color: isActive
              ? const Color(0xFF4D9DFF).withValues(alpha: 0.28)
              : Colors.white.withValues(alpha: 0.04),
          border: isActive ? Border.all(color: const Color(0xFF4D9DFF)) : null,
          borderRadius: BorderRadius.circular(10),
        ),
        child: Row(
          children: [
            Expanded(
              flex: 2,
              child: Text(m.name, style: const TextStyle(color: Colors.white)),
            ),
            Expanded(
              child: Text('${m.waypointCount} wp',
                  style: const TextStyle(color: Colors.white70)),
            ),
            Expanded(
              child: Text(_formatDate(m.updatedAt),
                  style: const TextStyle(color: Colors.white70)),
            ),
            IconButton(
              onPressed: () => _renameMission(m),
              icon: const Icon(Icons.edit, color: Colors.white70, size: 18),
            ),
            IconButton(
              onPressed: () => _shareMission(m),
              icon: const Icon(Icons.share, color: Color(0xFF4D9DFF), size: 18),
            ),
            IconButton(
              onPressed: () => ref.read(missionRepositoryProvider).delete(m.id),
              icon: const Icon(Icons.delete_outline,
                  color: Color(0xFFE2574A), size: 18),
            ),
          ],
        ),
      ),
    );
  }

  /// Teilt eine gespeicherte Mission als JSON-Datei ueber das native
  /// Share-Sheet (Doku 3.6, analog shareMission() im HTML-Demonstrator) -
  /// laedt zuerst die vollstaendige Wegpunktliste nach, da [MissionSummary]
  /// aus Speichergruenden nur die Anzahl fuehrt.
  Future<void> _shareMission(MissionSummary m) async {
    final full = await ref.read(missionRepositoryProvider).load(m.id);
    if (full == null) return;
    final json = buildMissionExportJson(MissionExportData(
      name: full.name,
      placeName: full.placeName,
      createdAt: full.createdAt,
      waypoints: full.waypoints,
    ));
    await ref.read(sharingServiceProvider).shareJsonFile(
          json: json,
          filename: missionExportFilename(full.placeName ?? full.name),
          shareTitle: 'Mission: ${full.placeName ?? full.name}',
        );
  }

  /// Importiert eine zuvor geteilte Missionsdatei als neue, eigenstaendige
  /// Mission (Doku 3.6, analog dem `change`-Handler von importMissionInput
  /// im HTML-Demonstrator) - ueberschreibt nie eine bestehende Mission.
  Future<void> _importMission() async {
    final messenger = ScaffoldMessenger.of(context);
    final text = await ref.read(sharingServiceProvider).pickJsonFileText();
    if (text == null) return;
    final ParsedMissionImport parsed;
    try {
      parsed = parseMissionImportJson(text);
    } on FormatException catch (e) {
      messenger.showSnackBar(SnackBar(content: Text(e.message)));
      return;
    }
    await ref.read(missionRepositoryProvider).upsert(
          name: parsed.name,
          placeName: parsed.placeName,
          waypoints: parsed.waypoints,
        );
    if (parsed.versionMismatch != null) {
      messenger.showSnackBar(SnackBar(
        content: Text(
            'Imported from a different app version (${parsed.versionMismatch}) – check carefully'),
      ));
    } else {
      messenger.showSnackBar(const SnackBar(content: Text('Mission imported')));
    }
  }

  Future<void> _renameMission(MissionSummary m) async {
    final controller = TextEditingController(text: m.name);
    final newName = await showDialog<String>(
      context: context,
      builder: (context) => AlertDialog(
        backgroundColor: const Color(0xFF1A1A1A),
        title: const Text('Rename mission', style: TextStyle(color: Colors.white)),
        content: TextField(
          controller: controller,
          autofocus: true,
          style: const TextStyle(color: Colors.white),
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.of(context).pop(),
            child: const Text('Cancel'),
          ),
          TextButton(
            onPressed: () => Navigator.of(context).pop(controller.text.trim()),
            child: const Text('Rename'),
          ),
        ],
      ),
    );
    if (newName == null || newName.isEmpty) return;
    await ref.read(currentMissionMetaProvider.notifier).renameMission(m.id, newName);
  }

  String _formatDate(DateTime dt) =>
      '${dt.day.toString().padLeft(2, '0')}.${dt.month.toString().padLeft(2, '0')}.${dt.year}';

  // --- Drones ---

  Widget _dronesTab() {
    final profiles = ref.watch(droneProfilesProvider);
    final activeId = ref.watch(activeDroneProfileProvider).id;

    return Column(
      children: [
        Padding(
          padding: const EdgeInsets.all(12),
          child: Row(
            children: [
              _ToolbarButton(
                icon: Icons.add,
                label: 'New profile',
                onTap: () => Navigator.of(context).push(MaterialPageRoute(
                  builder: (_) => const DroneProfileEditor(),
                )),
              ),
              const SizedBox(width: 8),
              _ToolbarButton(
                icon: Icons.file_upload_outlined,
                label: 'Import',
                onTap: _importDrone,
              ),
            ],
          ),
        ),
        Expanded(
          child: profiles.when(
            data: (drones) => ListView.builder(
              padding: const EdgeInsets.symmetric(horizontal: 16),
              itemCount: drones.length,
              itemBuilder: (context, index) =>
                  _droneRow(drones[index], drones, isActive: drones[index].id == activeId),
            ),
            loading: () => const Center(
              child: CircularProgressIndicator(color: Color(0xFF4D9DFF)),
            ),
            error: (err, st) => Center(
              child: Text('Error loading drones: $err',
                  style: const TextStyle(color: Color(0xFFE2574A))),
            ),
          ),
        ),
      ],
    );
  }

  Widget _droneRow(DroneProfile d, List<DroneProfile> all, {required bool isActive}) {
    return GestureDetector(
      onTap: () async {
        await ref.read(activeDroneProfileProvider.notifier).select(d);
        if (mounted) Navigator.of(context).pop();
      },
      child: Container(
        margin: const EdgeInsets.symmetric(vertical: 4),
        padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 10),
        decoration: BoxDecoration(
          color: isActive
              ? const Color(0xFF4D9DFF).withValues(alpha: 0.28)
              : Colors.white.withValues(alpha: 0.04),
          border: isActive ? Border.all(color: const Color(0xFF4D9DFF)) : null,
          borderRadius: BorderRadius.circular(10),
        ),
        child: Row(
          children: [
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(d.name,
                      style: const TextStyle(
                          color: Colors.white, fontWeight: FontWeight.w600)),
                  Text(d.summary,
                      style: const TextStyle(color: Colors.white60, fontSize: 12)),
                ],
              ),
            ),
            IconButton(
              onPressed: () => Navigator.of(context).push(MaterialPageRoute(
                builder: (_) => DroneProfileEditor(existing: d),
              )),
              icon: const Icon(Icons.edit, color: Colors.white70, size: 18),
            ),
            IconButton(
              onPressed: () => _shareDrone(d),
              icon: const Icon(Icons.share, color: Color(0xFF4D9DFF), size: 18),
            ),
            IconButton(
              onPressed: () => _deleteDrone(d, all),
              icon: const Icon(Icons.delete_outline,
                  color: Color(0xFFE2574A), size: 18),
            ),
          ],
        ),
      ),
    );
  }

  Future<void> _deleteDrone(DroneProfile d, List<DroneProfile> all) async {
    if (all.length <= 1) {
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('At least one drone profile is required')),
      );
      return;
    }
    final wasActive = ref.read(activeDroneProfileProvider).id == d.id;
    await ref.read(droneProfileRepositoryProvider).delete(d.id!);
    if (wasActive) {
      final remaining = all.where((p) => p.id != d.id).toList();
      await ref.read(activeDroneProfileProvider.notifier).fallBackTo(remaining.first);
    }
  }

  /// Teilt ein Drohnenprofil als JSON-Datei ueber das native Share-Sheet
  /// (Doku 3.5, analog shareDrone() im HTML-Demonstrator).
  Future<void> _shareDrone(DroneProfile d) async {
    final json = buildDroneExportJson(d);
    await ref.read(sharingServiceProvider).shareJsonFile(
          json: json,
          filename: droneExportFilename(d.name),
          shareTitle: 'Drone profile: ${d.name}',
        );
  }

  /// Importiert ein zuvor geteiltes Drohnenprofil als neues, eigenstaendiges
  /// Profil (Doku 3.5, analog dem `change`-Handler von importDroneInput im
  /// HTML-Demonstrator) - ueberschreibt nie ein bestehendes Profil.
  Future<void> _importDrone() async {
    final messenger = ScaffoldMessenger.of(context);
    final text = await ref.read(sharingServiceProvider).pickJsonFileText();
    if (text == null) return;
    final ParsedDroneImport parsed;
    try {
      parsed = parseDroneImportJson(text);
    } on FormatException catch (e) {
      messenger.showSnackBar(SnackBar(content: Text(e.message)));
      return;
    }
    await ref.read(droneProfileRepositoryProvider).insert(parsed.profile);
    if (parsed.versionMismatch != null) {
      messenger.showSnackBar(SnackBar(
        content: Text(
            'Imported from a different app version (${parsed.versionMismatch}) – check carefully'),
      ));
    } else {
      messenger.showSnackBar(const SnackBar(content: Text('Drone profile imported')));
    }
  }
}

class _ToolbarButton extends StatelessWidget {
  const _ToolbarButton({required this.icon, required this.label, required this.onTap});

  final IconData icon;
  final String label;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: onTap,
      child: Container(
        padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 10),
        decoration: BoxDecoration(
          color: const Color(0xFF4D9DFF).withValues(alpha: 0.2),
          border: Border.all(color: const Color(0xFF4D9DFF).withValues(alpha: 0.5)),
          borderRadius: BorderRadius.circular(12),
        ),
        child: Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(icon, size: 16, color: const Color(0xFFCFE2FF)),
            const SizedBox(width: 6),
            Text(label,
                style: const TextStyle(
                    color: Color(0xFFCFE2FF), fontWeight: FontWeight.w600, fontSize: 14)),
          ],
        ),
      ),
    );
  }
}