import 'dart:async';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../../services/nymea_service.dart';
import '../../theme/app_theme.dart';
import '../../theme/etm_theme.dart';
import '../../widgets/timeline_slot_card.dart';

/// Écran "Timeline & décisions" — vue horaire des décisions EMS.
class TimelineScreen extends StatefulWidget {
  const TimelineScreen({super.key});

  @override
  State<TimelineScreen> createState() => _TimelineScreenState();
}

class _TimelineScreenState extends State<TimelineScreen> {
  String           _horizon = '24h';
  bool             _loading = true;
  List<TimelineSlot> _slots = [];
  Timer?           _autoRefresh;

  static const _horizons = ['12h', '24h', '48h'];

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) => _load());
    // Auto-refresh toutes les minutes
    _autoRefresh = Timer.periodic(const Duration(minutes: 1), (_) {
      if (mounted) _load(silent: true);
    });
  }

  @override
  void dispose() {
    _autoRefresh?.cancel();
    super.dispose();
  }

  Future<void> _load({bool silent = false}) async {
    if (!mounted) return;
    if (!silent) setState(() => _loading = true);
    // Génère des créneaux de démonstration (à brancher sur GetEnergyTimeline)
    await Future.delayed(const Duration(milliseconds: 400));
    if (!mounted) return;
    setState(() {
      _slots  = _generateDemoSlots();
      _loading = false;
    });
  }

  List<TimelineSlot> _generateDemoSlots() {
    final now    = DateTime.now();
    final start  = now.subtract(Duration(hours: now.hour)).copyWith(
        minute: 0, second: 0, microsecond: 0);
    final hours  = _horizonHours();
    final slots  = <TimelineSlot>[];

    for (int i = 0; i < hours; i++) {
      final slotStart = start.add(Duration(hours: i));
      final isNow = now.isAfter(slotStart) &&
          now.isBefore(slotStart.add(const Duration(hours: 1)));

      // Simulation d'une production PV en cloche
      final h        = slotStart.hour.toDouble();
      final solar    = (h >= 7 && h <= 19)
          ? (2800 * _bell(h, 13, 4)).clamp(0.0, 5000.0)
          : 0.0;
      final home     = 800 + (i % 3) * 200.0;
      final evW      = (h >= 10 && h <= 15) ? 1200.0 : 0.0;
      final battery  = (solar > home + evW) ? (solar - home - evW).clamp(0.0, 3000.0) : 0.0;
      final grid     = (solar - home - evW - battery);

      slots.add(TimelineSlot(
        start:     slotStart,
        end:       slotStart.add(const Duration(hours: 1)),
        solarW:    solar,
        homeW:     home,
        evW:       evW,
        batteryW:  battery,
        gridW:     grid,
        reasoning: _reasoning(solar, home, evW, battery, grid),
        savings:   grid < 0 ? grid.abs() / 1000 * 0.12 : 0,
        selfSufficiency: solar > 0
            ? (solar / (home + evW.abs())).clamp(0.0, 1.5) * 100
            : 0,
        isNow: isNow,
      ));
    }
    return slots;
  }

  double _bell(double x, double mu, double sigma) {
    final d = (x - mu) / sigma;
    return 1.0 / (sigma * 2.5066) * (1 / (1 + d * d));
  }

  String _reasoning(double solar, double home, double ev,
      double battery, double grid) {
    if (solar > home + ev + 500) {
      return 'Surplus solaire ${_kw(solar - home - ev)} — '
          '${battery > 0 ? 'charge batterie + ' : ''}'
          '${ev > 0 ? 'recharge VE' : 'export réseau'}';
    } else if (solar > 0 && solar >= home * 0.8) {
      return 'Solaire ≈ consommation de base — '
          '${ev == 0 ? 'VE en pause' : 'recharge VE en cours'}';
    } else {
      return 'Faible production solaire — import réseau ${_kw(grid.abs())}';
    }
  }

  String _kw(double w) {
    return w >= 1000
        ? '+${(w / 1000).toStringAsFixed(1)} kW'
        : '+${w.toStringAsFixed(0)} W';
  }

  int _horizonHours() => switch (_horizon) {
        '12h' => 12,
        '48h' => 48,
        _     => 24,
      };

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: const Color(0xFFF0F2F5),
      appBar: AppBar(
        title: const Text('Timeline & décisions'),
        backgroundColor: Colors.white,
        foregroundColor: const Color(0xFF1A1A2E),
        elevation: 0,
        actions: [
          // Sélecteur d'horizon
          Padding(
            padding: const EdgeInsets.only(right: 4),
            child: DropdownButton<String>(
              value: _horizon,
              underline: const SizedBox.shrink(),
              style: const TextStyle(
                  fontSize: 13,
                  color: Color(0xFF1A1A2E),
                  fontWeight: FontWeight.w500),
              items: _horizons
                  .map((h) =>
                      DropdownMenuItem(value: h, child: Text(h)))
                  .toList(),
              onChanged: (v) {
                if (v != null && v != _horizon) {
                  setState(() => _horizon = v);
                  _load();
                }
              },
            ),
          ),
          // Bouton actualiser
          IconButton(
            icon: const Icon(Icons.refresh_rounded),
            tooltip: 'Actualiser',
            onPressed: _load,
          ),
        ],
      ),
      body: _loading
          ? const Center(child: CircularProgressIndicator())
          : _slots.isEmpty
              ? _EmptyState(onRetry: _load)
              : ListView.builder(
                  padding: const EdgeInsets.symmetric(vertical: 8),
                  itemCount: _slots.length,
                  itemBuilder: (context, i) {
                    final slot = _slots[i];
                    return TimelineSlotCard(
                      slot: slot,
                      onOverride: () => _showOverrideSheet(context, slot),
                    );
                  },
                ),
    );
  }

  void _showOverrideSheet(BuildContext context, TimelineSlot slot) {
    showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(20)),
      ),
      builder: (_) => _OverrideSheet(slot: slot),
    );
  }
}

// ── Feuille d'override ────────────────────────────────────────────────────────
class _OverrideSheet extends StatefulWidget {
  final TimelineSlot slot;
  const _OverrideSheet({required this.slot});

  @override
  State<_OverrideSheet> createState() => _OverrideSheetState();
}

class _OverrideSheetState extends State<_OverrideSheet> {
  double _evW    = 0;
  bool   _dhwOn  = false;
  double _batW   = 0;  // >0 charge, <0 décharge
  String _reason = '';

  @override
  void initState() {
    super.initState();
    _evW   = widget.slot.evW;
    _batW  = widget.slot.batteryW;
  }

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: EdgeInsets.only(
          bottom: MediaQuery.of(context).viewInsets.bottom),
      child: SingleChildScrollView(
        child: Padding(
          padding: const EdgeInsets.all(20),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            mainAxisSize: MainAxisSize.min,
            children: [
              const Center(
                child: _DragHandle(),
              ),
              const SizedBox(height: 16),

              const Text('Modifier ce créneau',
                  style: TextStyle(
                      fontSize: 17, fontWeight: FontWeight.bold)),
              const SizedBox(height: 4),
              Text(
                '${_fmt(widget.slot.start)} – ${_fmt(widget.slot.end)}',
                style: const TextStyle(
                    fontSize: 13, color: AppTheme.textLight),
              ),
              const SizedBox(height: 20),

              // VE Charger
              if (widget.slot.evW >= 0) ...[
                const Text('🚗 VE Charger',
                    style: TextStyle(
                        fontWeight: FontWeight.w600, fontSize: 13)),
                const SizedBox(height: 6),
                Row(
                  children: [
                    const Text('0 W', style: TextStyle(fontSize: 11)),
                    Expanded(
                      child: Slider(
                        value: _evW,
                        min: 0, max: 7400,
                        divisions: 37,
                        label: '${_evW.toStringAsFixed(0)} W',
                        activeColor: AppTheme.accentTeal,
                        onChanged: (v) => setState(() => _evW = v),
                      ),
                    ),
                    const Text('7.4 kW', style: TextStyle(fontSize: 11)),
                  ],
                ),
                const SizedBox(height: 12),
              ],

              // Chauffe-eau
              Row(
                children: [
                  const Text('🌡️ Chauffe-eau',
                      style: TextStyle(
                          fontWeight: FontWeight.w600, fontSize: 13)),
                  const Spacer(),
                  Switch.adaptive(
                    value: _dhwOn,
                    activeColor: AppTheme.primaryGreen,
                    onChanged: (v) => setState(() => _dhwOn = v),
                  ),
                ],
              ),
              const SizedBox(height: 12),

              // Batterie
              const Text('🔋 Batterie',
                  style: TextStyle(
                      fontWeight: FontWeight.w600, fontSize: 13)),
              const SizedBox(height: 6),
              Row(
                children: [
                  const Text('Décharge',
                      style: TextStyle(fontSize: 11)),
                  Expanded(
                    child: Slider(
                      value: _batW,
                      min: -3000, max: 3000,
                      divisions: 30,
                      label: _batW == 0
                          ? '0 (pause)'
                          : '${_batW > 0 ? '+' : ''}${_batW.toStringAsFixed(0)} W',
                      activeColor: AppTheme.batteryGreen,
                      onChanged: (v) => setState(() => _batW = v),
                    ),
                  ),
                  const Text('Charge',
                      style: TextStyle(fontSize: 11)),
                ],
              ),
              const SizedBox(height: 16),

              // Raison
              TextFormField(
                initialValue: _reason,
                decoration: InputDecoration(
                  labelText: 'Raison (optionnel)',
                  hintText: 'Ex. Départ annulé ce soir',
                  border: OutlineInputBorder(
                      borderRadius: BorderRadius.circular(12)),
                  contentPadding: const EdgeInsets.symmetric(
                      horizontal: 14, vertical: 12),
                ),
                onChanged: (v) => _reason = v,
              ),
              const SizedBox(height: 20),

              // Boutons
              Row(
                children: [
                  Expanded(
                    child: OutlinedButton(
                      onPressed: () => Navigator.pop(context),
                      style: OutlinedButton.styleFrom(
                        shape: RoundedRectangleBorder(
                            borderRadius: BorderRadius.circular(12)),
                        padding:
                            const EdgeInsets.symmetric(vertical: 14),
                      ),
                      child: const Text('Annuler'),
                    ),
                  ),
                  const SizedBox(width: 12),
                  Expanded(
                    child: ElevatedButton(
                      style: ElevatedButton.styleFrom(
                        backgroundColor: ETMTheme.accentColor,
                        foregroundColor: Colors.white,
                        shape: RoundedRectangleBorder(
                            borderRadius: BorderRadius.circular(12)),
                        padding:
                            const EdgeInsets.symmetric(vertical: 14),
                      ),
                      onPressed: () {
                        Navigator.pop(context);
                        ScaffoldMessenger.of(context).showSnackBar(
                          const SnackBar(
                            content: Text('Override appliqué'),
                            behavior: SnackBarBehavior.floating,
                          ),
                        );
                      },
                      child: const Text('Appliquer'),
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 8),
            ],
          ),
        ),
      ),
    );
  }

  String _fmt(DateTime dt) =>
      '${dt.hour.toString().padLeft(2, '0')}:${dt.minute.toString().padLeft(2, '0')}';
}

class _DragHandle extends StatelessWidget {
  const _DragHandle();

  @override
  Widget build(BuildContext context) {
    return Container(
      width: 36, height: 4,
      decoration: BoxDecoration(
        color: Colors.grey.shade300,
        borderRadius: BorderRadius.circular(2),
      ),
    );
  }
}

class _EmptyState extends StatelessWidget {
  final VoidCallback onRetry;
  const _EmptyState({required this.onRetry});

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          Icon(Icons.schedule_rounded,
              size: 48, color: Colors.grey.shade400),
          const SizedBox(height: 16),
          const Text('Aucune donnée de timeline',
              style: TextStyle(fontSize: 15)),
          const SizedBox(height: 8),
          const Text(
            'Le scheduler n\'a pas encore généré de planification.',
            textAlign: TextAlign.center,
            style: TextStyle(color: AppTheme.textLight),
          ),
          const SizedBox(height: 16),
          ElevatedButton.icon(
            icon: const Icon(Icons.refresh_rounded, size: 18),
            label: const Text('Réessayer'),
            style: ElevatedButton.styleFrom(
              backgroundColor: ETMTheme.accentColor,
              foregroundColor: Colors.white,
              shape: RoundedRectangleBorder(
                  borderRadius: BorderRadius.circular(12)),
            ),
            onPressed: onRetry,
          ),
        ],
      ),
    );
  }
}