// The Orin at a glance, the way a phone's status bar shows the phone: the link on the
// left, then its links out and its power on the right, and the dark/bright switch.
// Drawn by the shell above every view (DASH-NEXT.md item 1).
//
// An indicator shows its state in palette roles: foreground when fine, caution when
// degraded or on battery, alarm when down, subdued when stale or unknown. Things
// that are only news when wrong (temperature) appear only then; ones that are only
// news when present (the ELM, a modem) appear only then.

import 'package:flutter/material.dart';

import '../link/boundary.dart';
import '../link/reading.dart';
import '../theme/palette.dart';

class StatusBar extends StatelessWidget {
  const StatusBar({
    super.key,
    required this.boundary,
    required this.themes,
    this.leading,
  });
  final Boundary boundary;
  final Themes themes;

  /// Before the link state: the menu button, on a view with no app bar of its own.
  final Widget? leading;

  static const height = 32.0;

  @override
  Widget build(BuildContext context) {
    final p = AppTheme.of(context);
    final b = boundary;
    Reading r(String n) => Reading.of(b, n);
    final up = b.state == LinkState.up;
    final (text, color) = switch (b.state) {
      LinkState.up => ('LINK', p.subdued),
      LinkState.connecting => ('CONNECTING', p.caution),
      LinkState.down => ('NO LINK', p.alarm),
    };
    return SizedBox(
      height: height,
      child: IconTheme(
        data: IconThemeData(size: 18, color: p.foreground),
        child: DefaultTextStyle(
          style: TextStyle(
            fontSize: 14,
            color: p.foreground,
            fontFeatures: const [FontFeature.tabularFigures()],
          ),
          child: Row(
            children: [
              if (leading != null) leading! else const SizedBox(width: 16),
              Text(text, style: TextStyle(color: color, letterSpacing: 2)),
              const Spacer(),
              // Without the link, every Orin value is old news.
              if (up) ...[
                ..._temperature(p, r('orin_tj_temp_c')),
                ..._can(p, r('can_up'), r('can_bus_state')),
                ..._elm(p, r('elm_connected')),
                ..._gnss(p, r('gnss_fix'), r('gnss_satellites')),
                ..._lte(
                  p,
                  r('net_lte_state'),
                  r('net_lte_tech'),
                  r('net_lte_signal_pct'),
                ),
                ..._wifi(p, r('net_wifi_up'), r('net_wifi_signal_dbm')),
                ..._ups(p, r('ups_state'), r('ups_battery_pct')),
              ],
              _VariantButton(themes: themes),
            ],
          ),
        ),
      ),
    );
  }

  /// One indicator: an icon, maybe a short text, and the gap after it.
  static List<Widget> _item(Color c, {IconData? icon, String? text}) => [
    if (icon != null) Icon(icon, color: c),
    if (icon != null && text != null) const SizedBox(width: 2),
    if (text != null) Text(text, style: TextStyle(color: c)),
    const SizedBox(width: 14),
  ];

  /// Only when hot: caution from 80 °C, alarm from 90 (the Orin throttles near 99).
  static List<Widget> _temperature(Palette p, Reading t) {
    final c = t.number;
    if (t.dim || c == null || c < 80) return [];
    return _item(
      c >= 90 ? p.alarm : p.caution,
      icon: Icons.thermostat,
      text: '${c.round()}°',
    );
  }

  static List<Widget> _can(Palette p, Reading up, Reading state) {
    if (up.value == null) return _item(p.subdued, text: 'CAN');
    final color = switch ((up.on, state.value)) {
      (false, _) || (_, 'BUS-OFF') || (_, 'STOPPED') => p.alarm,
      (_, 'ERROR-WARNING') || (_, 'ERROR-PASSIVE') => p.caution,
      _ => p.foreground,
    };
    return _item(up.dim ? p.subdued : color, text: 'CAN');
  }

  /// The OBD-II adapter, only while connected (it is for calibration, not always on).
  static List<Widget> _elm(Palette p, Reading c) => c.on
      ? _item(
          c.dim ? p.subdued : p.foreground,
          icon: Icons.bluetooth_connected,
          text: 'OBD',
        )
      : [];

  static List<Widget> _gnss(Palette p, Reading fix, Reading sats) {
    final n = sats.number?.round();
    final (icon, color) = switch (fix.value) {
      '3d' => (Icons.gps_fixed, p.foreground),
      '2d' => (Icons.gps_fixed, p.caution),
      'none' => (Icons.gps_not_fixed, p.caution),
      _ => (Icons.gps_off, p.subdued),
    };
    return _item(
      fix.dim ? p.subdued : color,
      icon: icon,
      text: n == null ? null : '$n',
    );
  }

  /// The modem, when there is one: bars from its signal, and the technology.
  static List<Widget> _lte(
    Palette p,
    Reading state,
    Reading tech,
    Reading pct,
  ) {
    final s = state.value as String?;
    if (s == null) return [];
    final q = pct.number ?? 0;
    final t = (tech.value as String? ?? '').toUpperCase();
    final (icon, color) = switch (s) {
      'connected' => (
        q >= 60
            ? Icons.signal_cellular_alt
            : q >= 30
            ? Icons.signal_cellular_alt_2_bar
            : Icons.signal_cellular_alt_1_bar,
        p.foreground,
      ),
      'registered' ||
      'searching' ||
      'connecting' ||
      'enabling' => (Icons.signal_cellular_alt_1_bar, p.caution),
      _ => (Icons.signal_cellular_off, p.subdued),
    };
    return _item(
      state.dim ? p.subdued : color,
      icon: icon,
      text: t.isEmpty ? null : t,
    );
  }

  static List<Widget> _wifi(Palette p, Reading up, Reading dbm) {
    if (!up.on) return _item(p.subdued, icon: Icons.wifi_off);
    final d = dbm.number ?? -100;
    final icon = d >= -60
        ? Icons.wifi
        : d >= -70
        ? Icons.wifi_2_bar
        : Icons.wifi_1_bar;
    return _item(up.dim ? p.subdued : p.foreground, icon: icon);
  }

  /// The UPS: caution on battery (the car is off), alarm under 20 %.
  static List<Widget> _ups(Palette p, Reading state, Reading pct) {
    final n = pct.number;
    if (n == null) return _item(p.subdued, icon: Icons.battery_unknown);
    const bars = [
      Icons.battery_0_bar,
      Icons.battery_1_bar,
      Icons.battery_2_bar,
      Icons.battery_3_bar,
      Icons.battery_4_bar,
      Icons.battery_5_bar,
      Icons.battery_6_bar,
      Icons.battery_full,
    ];
    final charging = state.value == 'charging';
    final icon = charging
        ? Icons.battery_charging_full
        : bars[(n / 100 * 7).round().clamp(0, 7)];
    final color = n < 20
        ? p.alarm
        : state.value == 'discharging'
        ? p.caution
        : p.foreground;
    return _item(
      pct.dim ? p.subdued : color,
      icon: icon,
      text: '${n.round()}%',
    );
  }
}

/// Tap: hold the other variant. Long press: back to auto (Settings has all three).
class _VariantButton extends StatelessWidget {
  const _VariantButton({required this.themes});
  final Themes themes;

  @override
  Widget build(BuildContext context) {
    final p = AppTheme.of(context);
    return GestureDetector(
      onLongPress: () => themes.mode = VariantMode.auto,
      child: IconButton(
        tooltip: themes.isDark ? 'Bright' : 'Dark',
        onPressed: themes.toggle,
        iconSize: 20,
        visualDensity: VisualDensity.compact,
        icon: Icon(
          themes.mode == VariantMode.auto
              ? Icons.brightness_auto
              : (themes.isDark ? Icons.light_mode : Icons.dark_mode),
          color: p.subdued,
        ),
      ),
    );
  }
}