import 'dart:math' as math;
import 'package:flutter/material.dart';
import '../models/energy_data.dart';
import '../theme/etm_tokens.dart';

/// Diagramme de flux d'énergie animé — réutilisable Dashboard + Énergie.
///
/// Layout 4 nœuds : Solaire (haut centre), Maison (centre), Batterie (bas gauche),
/// Réseau (bas droite). Les lignes de flux sont animées via CustomPainter.
class EnergyFlowWidget extends StatefulWidget {
  final EnergyData data;
  const EnergyFlowWidget({super.key, required this.data});

  @override
  State<EnergyFlowWidget> createState() => _EnergyFlowWidgetState();
}

class _EnergyFlowWidgetState extends State<EnergyFlowWidget>
    with SingleTickerProviderStateMixin {
  late AnimationController _ctrl;

  @override
  void initState() {
    super.initState();
    _ctrl = AnimationController(
      vsync: this,
      duration: const Duration(milliseconds: 1400),
    )..repeat();
  }

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

  @override
  Widget build(BuildContext context) {
    final data = widget.data;
    return Container(
      decoration: BoxDecoration(
        color: EtmTokens.card,
        borderRadius: BorderRadius.circular(EtmTokens.radiusLg),
        boxShadow: EtmTokens.cardShadow,
      ),
      padding: const EdgeInsets.all(20),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          // Header
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [
              Text('Flux d\'énergie en temps réel',
                  style: EtmTokens.sans(size: 17, weight: FontWeight.w600)),
              Row(
                children: [
                  Text('${data.temperature.toStringAsFixed(0)}°C',
                      style: EtmTokens.sans(size: 14, color: EtmTokens.muted)),
                  const SizedBox(width: 4),
                  const Icon(Icons.wb_cloudy_outlined, color: EtmTokens.faint, size: 20),
                ],
              ),
            ],
          ),
          const SizedBox(height: 16),

          // Flow diagram
          SizedBox(
            height: 240,
            child: LayoutBuilder(
              builder: (context, constraints) {
                final w = constraints.maxWidth;
                final h = constraints.maxHeight;
                final nodeR = w * 0.13; // rayon nœud ≈52px sur 400px
                final nodes = _NodePositions(w: w, h: h, r: nodeR);
                return AnimatedBuilder(
                  animation: _ctrl,
                  builder: (_, __) => Stack(
                    clipBehavior: Clip.none,
                    children: [
                      Positioned.fill(
                        child: CustomPaint(
                          painter: _FlowPainter(
                            nodes: nodes,
                            data: data,
                            t: _ctrl.value,
                          ),
                        ),
                      ),
                      _sunNode(center: nodes.sun, r: nodeR, data: data),
                      _homeNode(center: nodes.home, r: nodeR * 1.08, data: data),
                      _battNode(center: nodes.batt, r: nodeR, data: data),
                      _gridNode(center: nodes.grid, r: nodeR, data: data),
                    ],
                  ),
                );
              },
            ),
          ),

          // Footer mode optimal
          const SizedBox(height: 6),
          _OptimalBanner(),
        ],
      ),
    );
  }
}

// ─────────────────────────── Positions ─────────────────────────────────────────

class _NodePositions {
  final double w, h, r;
  late final Offset sun, home, batt, grid;

  _NodePositions({required this.w, required this.h, required this.r}) {
    sun  = Offset(w * 0.5,  h * 0.19);
    home = Offset(w * 0.5,  h * 0.73);
    batt = Offset(w * 0.14, h * 0.73);
    grid = Offset(w * 0.86, h * 0.73);
  }
}

// ─────────────────────────── Painter ───────────────────────────────────────────

class _FlowPainter extends CustomPainter {
  final _NodePositions nodes;
  final EnergyData data;
  final double t;

  const _FlowPainter({required this.nodes, required this.data, required this.t});

  @override
  void paint(Canvas canvas, Size size) {
    final r = nodes.r;

    // Sun → Home
    _line(
      canvas,
      from: Offset(nodes.sun.dx, nodes.sun.dy + r),
      to:   Offset(nodes.home.dx, nodes.home.dy - r * 1.08),
      color: data.pvPower > 0 ? EtmTokens.amber : EtmTokens.line,
      animated: data.pvPower > 0,
      arrowDown: true,
    );

    // Home ↔ Battery
    final battFlow = data.batteryPower;
    if (battFlow > 0) {
      // Charging: Home → Battery
      _line(canvas,
          from: Offset(nodes.home.dx - r * 1.08, nodes.home.dy),
          to:   Offset(nodes.batt.dx + r, nodes.batt.dy),
          color: EtmTokens.green, animated: true, arrowLeft: true);
    } else if (battFlow < 0) {
      // Discharging: Battery → Home
      _line(canvas,
          from: Offset(nodes.batt.dx + r, nodes.batt.dy),
          to:   Offset(nodes.home.dx - r * 1.08, nodes.home.dy),
          color: EtmTokens.amber, animated: true, arrowLeft: false);
    } else {
      _line(canvas,
          from: Offset(nodes.home.dx - r * 1.08, nodes.home.dy),
          to:   Offset(nodes.batt.dx + r, nodes.batt.dy),
          color: EtmTokens.line, animated: false);
    }

    // Réseau ↔ Maison  (gridPower > 0 = soutirage = Grid → Home)
    final gridFlow = data.gridPower;
    final homeRight = Offset(nodes.home.dx + r * 1.08, nodes.home.dy);
    final gridLeft  = Offset(nodes.grid.dx - r,         nodes.grid.dy);
    if (gridFlow > 20) {
      // Soutirage : Grid → Home (amber)
      _line(canvas, from: gridLeft, to: homeRight,
          color: EtmTokens.amber, animated: true);
    } else if (gridFlow < -20) {
      // Injection : Home → Grid (blue)
      _line(canvas, from: homeRight, to: gridLeft,
          color: EtmTokens.blue, animated: true);
    } else {
      _line(canvas, from: homeRight, to: gridLeft,
          color: EtmTokens.line, animated: false);
    }
  }

  void _line(
    Canvas canvas, {
    required Offset from,
    required Offset to,
    required Color color,
    required bool animated,
    bool arrowDown = false,
    bool arrowLeft = false,
  }) {
    final dx = to.dx - from.dx;
    final dy = to.dy - from.dy;
    final len = math.sqrt(dx * dx + dy * dy);
    if (len < 1) return;

    final paint = Paint()
      ..color = color
      ..strokeWidth = 2.5
      ..style = PaintingStyle.stroke
      ..strokeCap = StrokeCap.round;

    const dash = 4.0;
    const gap  = 7.0;
    const period = dash + gap;

    final offset = animated ? (t * period) % period : 0.0;
    double dist = -offset;

    while (dist < len) {
      final d0 = dist.clamp(0.0, len);
      final d1 = (dist + dash).clamp(0.0, len);
      if (d1 > d0) {
        canvas.drawLine(
          Offset(from.dx + dx / len * d0, from.dy + dy / len * d0),
          Offset(from.dx + dx / len * d1, from.dy + dy / len * d1),
          paint,
        );
      }
      dist += period;
    }

    // Arrow head at destination
    if (animated) {
      _arrow(canvas, from, to, color);
    }
  }

  void _arrow(Canvas canvas, Offset from, Offset to, Color color) {
    final dx = to.dx - from.dx;
    final dy = to.dy - from.dy;
    final len = math.sqrt(dx * dx + dy * dy);
    if (len < 1) return;
    final nx = dx / len;
    final ny = dy / len;
    const size = 7.0;
    final tip = to;
    final p1 = Offset(tip.dx - nx * size + ny * size * 0.5,
                      tip.dy - ny * size - nx * size * 0.5);
    final p2 = Offset(tip.dx - nx * size - ny * size * 0.5,
                      tip.dy - ny * size + nx * size * 0.5);
    final path = Path()..moveTo(tip.dx, tip.dy)..lineTo(p1.dx, p1.dy)..lineTo(p2.dx, p2.dy)..close();
    canvas.drawPath(path, Paint()..color = color..style = PaintingStyle.fill);
  }

  @override
  bool shouldRepaint(_FlowPainter old) =>
      old.t != t || old.data.pvPower != data.pvPower ||
      old.data.batteryPower != data.batteryPower ||
      old.data.gridPower != data.gridPower;
}

// ─────────────────────────── Nœuds ─────────────────────────────────────────────

Widget _sunNode({required Offset center, required double r, required EnergyData data}) {
  final kw = (data.pvPower / 1000);
  return _Node(
    center: center,
    r: r,
    borderColor: const Color(0xFFFDE9A8),
    icon: Icons.wb_sunny_rounded,
    iconColor: EtmTokens.amber,
    label: 'Solaire',
    value: '${kw.toStringAsFixed(2)} kW',
    valueColor: EtmTokens.amber,
  );
}

Widget _homeNode({required Offset center, required double r, required EnergyData data}) {
  return _Node(
    center: center,
    r: r,
    borderColor: const Color(0xFFBFE2F3),
    ringColor: const Color(0xFFEAF6FC),
    icon: Icons.home_rounded,
    iconColor: EtmTokens.blue,
    label: 'Maison',
    value: '${data.homePower.toStringAsFixed(0)} W',
    valueColor: EtmTokens.blue,
  );
}

Widget _battNode({required Offset center, required double r, required EnergyData data}) {
  final sign = data.batteryPower > 0 ? '+ ' : data.batteryPower < 0 ? '− ' : '';
  return _Node(
    center: center,
    r: r,
    borderColor: const Color(0xFFC4EED7),
    icon: Icons.battery_charging_full_rounded,
    iconColor: EtmTokens.green,
    label: 'Batterie',
    value: '${data.batterySOC.toStringAsFixed(0)}%',
    valueColor: EtmTokens.green,
    sub: '$sign${data.batteryPower.abs().toStringAsFixed(0)} W',
    subColor: EtmTokens.green,
  );
}

Widget _gridNode({required Offset center, required double r, required EnergyData data}) {
  return _Node(
    center: center,
    r: r,
    icon: Icons.electrical_services_rounded,
    iconColor: EtmTokens.faint,
    label: 'Réseau',
    value: '${data.gridPower.abs().toStringAsFixed(0)} W',
    valueColor: EtmTokens.muted,
  );
}

class _Node extends StatelessWidget {
  final Offset center;
  final double r;
  final Color? borderColor;
  final Color? ringColor;
  final IconData icon;
  final Color iconColor;
  final String label;
  final String value;
  final Color valueColor;
  final String? sub;
  final Color? subColor;

  const _Node({
    required this.center,
    required this.r,
    this.borderColor,
    this.ringColor,
    required this.icon,
    required this.iconColor,
    required this.label,
    required this.value,
    required this.valueColor,
    this.sub,
    this.subColor,
  });

  @override
  Widget build(BuildContext context) {
    final diameter = r * 2;
    return Positioned(
      left: center.dx - r,
      top: center.dy - r,
      width: diameter,
      height: diameter + 32, // extra for label below
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          Container(
            width: diameter,
            height: diameter,
            decoration: BoxDecoration(
              color: Colors.white,
              shape: BoxShape.circle,
              border: Border.all(
                color: borderColor ?? EtmTokens.line,
                width: 1.5,
              ),
              boxShadow: ringColor != null
                  ? [
                      BoxShadow(color: ringColor!, blurRadius: 0, spreadRadius: 5),
                      BoxShadow(
                          color: EtmTokens.navy.withValues(alpha: 0.08),
                          blurRadius: 16,
                          offset: const Offset(0, 4)),
                    ]
                  : [
                      BoxShadow(
                          color: EtmTokens.navy.withValues(alpha: 0.08),
                          blurRadius: 16,
                          offset: const Offset(0, 4)),
                    ],
            ),
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                Icon(icon, color: iconColor, size: r * 0.56),
                const SizedBox(height: 2),
                Text(value, style: EtmTokens.mono(size: r * 0.32, color: valueColor)),
                if (sub != null)
                  Text(sub!, style: EtmTokens.mono(size: r * 0.26, color: subColor ?? EtmTokens.muted)),
              ],
            ),
          ),
          const SizedBox(height: 4),
          Text(
            label,
            style: EtmTokens.sans(size: 11, color: EtmTokens.muted),
            textAlign: TextAlign.center,
          ),
        ],
      ),
    );
  }
}

// ─────────────────────────── Bannière ──────────────────────────────────────────

class _OptimalBanner extends StatelessWidget {
  const _OptimalBanner();

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 12),
      decoration: BoxDecoration(
        color: EtmTokens.greenSoft,
        borderRadius: BorderRadius.circular(14),
      ),
      child: Row(
        children: [
          Container(
            width: 32, height: 32,
            decoration: const BoxDecoration(color: EtmTokens.green, shape: BoxShape.circle),
            child: const Icon(Icons.check, color: Colors.white, size: 18),
          ),
          const SizedBox(width: 12),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text('Mode optimal',
                    style: EtmTokens.sans(size: 14, weight: FontWeight.w600, color: EtmTokens.greenDark)),
                Text('Héos optimise votre consommation',
                    style: EtmTokens.sans(size: 12, color: EtmTokens.muted)),
              ],
            ),
          ),
          const Icon(Icons.chevron_right, color: EtmTokens.faint, size: 20),
        ],
      ),
    );
  }
}