import '../../dji_service.dart';
import '../hud_features.dart';
import '../product_profile.dart';
import '../state/aircraft_state.dart';
import '../state/key_state.dart';
import '../state/parse.dart';

/// What a row's predicates may look at.
class SettingsContext {
  const SettingsContext({required this.profile, required this.keys, required this.aircraft});

  final ProductProfile profile;
  final KeyState keys;
  final AircraftState aircraft;

  bool get connected => profile.connected;

  /// Airborne or motors running: the FC refuses some settings then.
  bool get airborne => aircraft.isFlying == true || aircraft.motorsOn == true;
}

/// One row of the settings sheet (plan P6, §1.4): data, not widgets, so a new
/// setting is one line in `settings_tabs.dart`.
///
/// A row bound to a [key] hides once that key is known to be unsupported on
/// the connected product; [requires] gates it on the profile like any HUD
/// element; [visibleWhen] hides it on another setting's value (the distance
/// value only while the limit is on). [groundOnly] rows are locked while the
/// aircraft is airborne or the motors run.
sealed class SettingSpec {
  const SettingSpec({required this.id, required this.label, this.hint, this.requires, this.visibleWhen, this.groundOnly = false});

  final String id;
  final String label;
  final String? hint;
  final HudFeature? requires;
  final bool Function(SettingsContext c)? visibleWhen;
  final bool groundOnly;

  /// The key the row reads, or null for app-side rows.
  DjiKey? get key => null;

  /// Every key the row needs listened to.
  Iterable<DjiKey> get watched => key == null ? const <DjiKey>[] : <DjiKey>[key!];

  bool visible(SettingsContext c) {
    if (requires != null && c.connected && !requires!.enabledFor(c.profile)) return false;
    final DjiKey? k = key;
    if (k != null && c.keys.supported(k) == false) return false;
    return visibleWhen?.call(c) ?? true;
  }

  /// Why the row cannot be changed right now, or null.
  String? lockedReason(SettingsContext c) {
    if (key == null) return null;
    if (!c.connected) return 'Connect the aircraft to change';
    if (groundOnly && c.airborne) return 'Land and stop the motors to change';
    return null;
  }
}

/// A section label.
class GroupSpec extends SettingSpec {
  const GroupSpec(String label, {super.requires, super.visibleWhen}) : super(id: 'group-$label', label: label);
}

class KeySwitchSpec extends SettingSpec {
  const KeySwitchSpec({
    required super.id,
    required super.label,
    required DjiKey key,
    super.hint,
    super.requires,
    super.visibleWhen,
    super.groundOnly,
  }) : _key = key;

  final DjiKey _key;
  @override
  DjiKey get key => _key;

  bool? current(KeyState s) => asBool(s.value(_key));
}

/// An SDK enum, offered as chips. [options] are (enum name, label); when
/// [supportedKey] reports a list of names, only those are offered.
class KeyChoiceSpec extends SettingSpec {
  const KeyChoiceSpec({
    required super.id,
    required super.label,
    required DjiKey key,
    required this.options,
    this.supportedKey,
    super.hint,
    super.requires,
    super.visibleWhen,
    super.groundOnly,
  }) : _key = key;

  final DjiKey _key;
  final List<(String, String)> options;
  final DjiKey? supportedKey;

  @override
  DjiKey get key => _key;

  @override
  Iterable<DjiKey> get watched => <DjiKey>[_key, if (supportedKey != null) supportedKey!];

  String? current(KeyState s) => asString(s.value(_key));

  List<(String, String)> optionsFor(KeyState s) {
    final Object? names = supportedKey == null ? null : s.value(supportedKey!);
    final List<(String, String)> offered =
        names is List ? <(String, String)>[for (final (String, String) o in options) if (names.contains(o.$1)) o] : options;
    // A value the table does not know (STYLE_CUSTOM set elsewhere) still shows.
    final String? v = current(s);
    if (v != null && !offered.any(((String, String) o) => o.$1 == v)) {
      return <(String, String)>[...offered, (v, prettyEnum(v))];
    }
    return offered;
  }
}

/// An integer stepped between bounds. The bounds come from [rangeKey] when the
/// aircraft reports one (`{min, max}` or `[min, max]`), else [min] / [max];
/// [bounds] narrows them further from other settings.
class KeyNumberSpec extends SettingSpec {
  const KeyNumberSpec({
    required super.id,
    required super.label,
    required DjiKey key,
    required this.min,
    required this.max,
    this.step = 1,
    this.unit = '',
    this.rangeKey,
    this.bounds,
    this.feet = false,
    super.hint,
    super.requires,
    super.visibleWhen,
    super.groundOnly,
  }) : _key = key;

  final DjiKey _key;
  final int min;
  final int max;
  final int step;
  final String unit;
  final DjiKey? rangeKey;
  final (int, int) Function(KeyState s, int min, int max)? bounds;

  /// Metres: show "≈ N ft" beside the value.
  final bool feet;

  @override
  DjiKey get key => _key;

  @override
  Iterable<DjiKey> get watched => <DjiKey>[_key, if (rangeKey != null) rangeKey!];

  int? current(KeyState s) => asInt(s.value(_key));

  (int, int) range(KeyState s) {
    int lo = min, hi = max;
    final Object? r = rangeKey == null ? null : s.value(rangeKey!);
    final Map<String, dynamic>? m = asMap(r);
    if (m != null && m['supported'] != false && asInt(m['min']) != null && asInt(m['max']) != null) {
      lo = asInt(m['min'])!;
      hi = asInt(m['max'])!;
    } else if (r is List && r.length == 2 && asInt(r[0]) != null && asInt(r[1]) != null) {
      lo = asInt(r[0])!;
      hi = asInt(r[1])!;
    }
    if (bounds != null) (lo, hi) = bounds!(s, lo, hi);
    return (lo, hi);
  }

  /// [v] moved by one step in [dir], clamped, or null when it cannot move.
  int? stepped(KeyState s, int dir) {
    final int? v = current(s);
    if (v == null) return null;
    final (int lo, int hi) = range(s);
    final int next = (v + dir * step).clamp(lo, hi);
    return next == v ? null : next;
  }
}

/// A read-only value.
class KeyReadoutSpec extends SettingSpec {
  const KeyReadoutSpec({
    required super.id,
    required super.label,
    required DjiKey key,
    this.format = formatValue,
    super.hint,
    super.requires,
    super.visibleWhen,
  }) : _key = key;

  final DjiKey _key;
  final String Function(Object? v) format;

  @override
  DjiKey get key => _key;

  @override
  String? lockedReason(SettingsContext c) => null;

  String shown(KeyState s) {
    final Object? v = s.value(_key);
    return v == null ? '—' : format(v);
  }
}

/// A string the pilot types (aircraft name, a remote's name). [secret] masks
/// it and never shows the stored value; [maxLength] caps what is typed;
/// [send] replaces the plain `setKey` for values the SDK only takes through a
/// bespoke method.
class KeyTextSpec extends SettingSpec {
  const KeyTextSpec({
    required super.id,
    required super.label,
    required DjiKey key,
    this.secret = false,
    this.maxLength = 32,
    this.send,
    super.hint,
    super.requires,
    super.visibleWhen,
    super.groundOnly,
  }) : _key = key;

  final DjiKey _key;
  final bool secret;
  final int maxLength;
  final Future<void> Function(DjiService dji, String value)? send;

  @override
  DjiKey get key => _key;

  String? current(KeyState s) => asString(s.value(_key));

  String shown(KeyState s) {
    final String? v = current(s);
    if (secret) return v == null || v.isEmpty ? '—' : '••••••';
    return v == null || v.isEmpty ? '—' : v;
  }
}

/// A button that runs an argument-less action key (`START_PAIRING`).
class KeyActionSpec extends SettingSpec {
  const KeyActionSpec({
    required super.id,
    required super.label,
    required DjiKey key,
    required this.button,
    this.confirmTitle,
    this.confirmText,
    super.hint,
    super.requires,
    super.visibleWhen,
    super.groundOnly,
  }) : _key = key;

  final DjiKey _key;
  final String button;
  final String? confirmTitle;
  final String? confirmText;

  @override
  DjiKey get key => _key;

  /// Action keys are not values: `isKeySupported` is the only gate.
  @override
  Iterable<DjiKey> get watched => const <DjiKey>[];
}

/// A row the sheet draws itself (home point, stick-mode diagram, the gimbal
/// list, app preferences, About). [keys] are still watched and gate nothing.
class CustomSpec extends SettingSpec {
  const CustomSpec({required super.id, super.label = '', this.keys = const <DjiKey>[], super.requires, super.visibleWhen});

  final List<DjiKey> keys;

  @override
  Iterable<DjiKey> get watched => keys;
}

/// A tab of the sheet.
class SettingsTab {
  const SettingsTab({required this.id, required this.label, required this.icon, required this.rows, this.requires});

  final String id;
  final String label;

  /// A `PVIcon` name.
  final String icon;
  final List<SettingSpec> rows;
  final HudFeature? requires;

  Iterable<DjiKey> get watched sync* {
    for (final SettingSpec r in rows) {
      yield* r.watched;
      if (r is KeyActionSpec) yield r.key;
    }
  }

  bool visible(ProductProfile p) => requires == null || !p.connected || requires!.enabledFor(p);
}

// ── Formatting ────────────────────────────────────────────────────────────────

/// `FREQUENCY_BAND_2_DOT_4_GHZ` → `Frequency band 2.4 ghz`-ish fallback label.
String prettyEnum(String v) {
  final String s = v.replaceAll('_DOT_', '.').replaceAll('_', ' ').toLowerCase();
  return s.isEmpty ? v : s[0].toUpperCase() + s.substring(1);
}

String formatValue(Object? v) => switch (v) {
      null => '—',
      bool b => b ? 'On' : 'Off',
      double d => d == d.roundToDouble() ? d.toInt().toString() : d.toStringAsFixed(1),
      String s when s.toUpperCase() == s && s.contains('_') => prettyEnum(s),
      List<Object?> l => l.map(formatValue).join(', '),
      _ => v.toString(),
    };

/// `≈ 394 ft` for [m] metres.
String feetHint(int m) => '≈ ${(m * 3.28084).round()} ft';

/// One battery `WarningRecord` (as `KeyBridge.kt` maps it) → what went wrong.
String formatWarningRecord(Object? v) {
  final Map<String, dynamic>? m = asMap(v);
  if (m == null) return formatValue(v);
  final List<String> found = <String>[
    if (asBool(m['overCurrent']) == true) 'over-current',
    if (asBool(m['overHeated']) == true) 'overheated',
    if (asBool(m['lowTemperature']) == true) 'too cold',
    if (asBool(m['shortCircuit']) == true) 'short circuit',
    if (asBool(m['underVoltage']) == true) 'under-voltage',
    if ((asInt(m['lowVoltageCell']) ?? 0) > 0) 'low cell ${asInt(m['lowVoltageCell'])}',
    if ((asInt(m['damagedCell']) ?? 0) > 0) 'damaged cell ${asInt(m['damagedCell'])}',
  ];
  if (found.isEmpty) return asBool(m['error']) == true ? 'Error' : 'None';
  return found.join(', ');
}

/// A list of `WarningRecord`s → how many flights had a warning, and the worst.
String formatWarningHistory(Object? v) {
  if (v is! List) return formatValue(v);
  if (v.isEmpty) return 'None';
  final List<String> bad = <String>[
    for (final Object? r in v)
      if (formatWarningRecord(r) case final String s when s != 'None') s,
  ];
  if (bad.isEmpty) return 'None in ${v.length} records';
  return '${bad.length} of ${v.length}: ${bad.first}';
}

/// Millivolt cell list → `3.85  3.86  3.84 V`.
String formatCells(Object? v) {
  if (v is! List || v.isEmpty) return '—';
  return '${v.map((Object? mv) => mv is num ? (mv / 1000).toStringAsFixed(2) : '?').join('  ')} V';
}