import 'package:flutter/material.dart';

import '../l10n/gen/app_localizations.dart';
import '../tema/pluriwave_theme.dart';

/// Giant inline HH:MM editor (WU10, `native-alarms` delta — Alarm Editor
/// Preserves Date, Fallback Station, and Sound Fields): replaces the native
/// `showTimePicker` dialog inside `_EditorAlarmaSheet`. Standalone and
/// independent of the sheet — it only exposes `value`/`onChanged`, so it can
/// be unit-tested (and reused) with no alarm/editor state at all.
///
/// Each segment (hour, minute) supports two independent adjustment paths:
/// - Tap: increments that segment by one step, wrapping (`23:59` + 1 minute
///   wraps to `00:00`, matching a real clock's minute rollover).
/// - Vertical drag: continuous bidirectional adjustment — up increases, down
///   decreases — for users who want to scrub several steps at once.
///
/// Screen readers get BOTH directions regardless of the touch affordance:
/// each segment exposes `Semantics.onIncrease`/`onDecrease` (the same
/// adjustable-control pattern `Slider` uses internally), so a drag gesture is
/// never required for accessible use.
class EditorHoraInline extends StatefulWidget {
  const EditorHoraInline({
    super.key,
    required this.value,
    required this.onChanged,
  });

  final TimeOfDay value;
  final ValueChanged<TimeOfDay> onChanged;

  @override
  State<EditorHoraInline> createState() => _EditorHoraInlineState();
}

class _EditorHoraInlineState extends State<EditorHoraInline> {
  /// Logical pixels of accumulated vertical drag per one-unit step. Chosen
  /// for a comfortable scrub distance — not derived from any measured
  /// constant, this widget has no other consumer to stay in sync with.
  static const double _pixelesPorPaso = 24;

  double _arrastreHora = 0;
  double _arrastreMinuto = 0;

  /// Pure preview: the hour after applying [delta], wrapping 23→0 / 0→23.
  /// Shared by the actual mutation and by the `Semantics`
  /// increasedValue/decreasedValue text (Flutter requires both whenever
  /// `onIncrease`/`onDecrease` are set).
  int _horaConDelta(int delta) {
    final horas = (widget.value.hour + delta) % 24;
    return horas < 0 ? horas + 24 : horas;
  }

  /// Pure preview: the minute after applying [delta] to the whole HH:MM,
  /// wrapping at the day boundary (`23:59` + 1 minute → `00:00`).
  TimeOfDay _horaCompletaConDeltaMinuto(int delta) {
    final totalMinutos = widget.value.hour * 60 + widget.value.minute + delta;
    final normalizado = totalMinutos % (24 * 60);
    final positivo = normalizado < 0 ? normalizado + 24 * 60 : normalizado;
    return TimeOfDay(hour: positivo ~/ 60, minute: positivo % 60);
  }

  void _ajustarHora(int delta) {
    if (delta == 0) return;
    widget.onChanged(
      TimeOfDay(hour: _horaConDelta(delta), minute: widget.value.minute),
    );
  }

  void _ajustarMinuto(int delta) {
    if (delta == 0) return;
    widget.onChanged(_horaCompletaConDeltaMinuto(delta));
  }

  void _onArrastreHora(DragUpdateDetails details) {
    // Screen-space dy grows downward, so an upward drag (negative dy) must
    // increase the value: subtract, don't add.
    _arrastreHora -= details.delta.dy;
    while (_arrastreHora >= _pixelesPorPaso) {
      _arrastreHora -= _pixelesPorPaso;
      _ajustarHora(1);
    }
    while (_arrastreHora <= -_pixelesPorPaso) {
      _arrastreHora += _pixelesPorPaso;
      _ajustarHora(-1);
    }
  }

  void _onArrastreMinuto(DragUpdateDetails details) {
    _arrastreMinuto -= details.delta.dy;
    while (_arrastreMinuto >= _pixelesPorPaso) {
      _arrastreMinuto -= _pixelesPorPaso;
      _ajustarMinuto(1);
    }
    while (_arrastreMinuto <= -_pixelesPorPaso) {
      _arrastreMinuto += _pixelesPorPaso;
      _ajustarMinuto(-1);
    }
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    final type = context.pluriType;
    final horaTexto = widget.value.hour.toString().padLeft(2, '0');
    final minutoTexto = widget.value.minute.toString().padLeft(2, '0');

    return FittedBox(
      fit: BoxFit.scaleDown,
      child: Row(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.center,
        children: [
          _Segmento(
            key: const ValueKey('editor-hora-inline-hora'),
            texto: horaTexto,
            semanticLabel: l10n.alarmInlineHourLabel,
            incrementado: _horaConDelta(1).toString().padLeft(2, '0'),
            decrementado: _horaConDelta(-1).toString().padLeft(2, '0'),
            style: type.heroTime,
            onTap: () => _ajustarHora(1),
            onIncrease: () => _ajustarHora(1),
            onDecrease: () => _ajustarHora(-1),
            onDragUpdate: _onArrastreHora,
          ),
          Text(':', style: type.heroTime),
          _Segmento(
            key: const ValueKey('editor-hora-inline-minuto'),
            texto: minutoTexto,
            semanticLabel: l10n.alarmInlineMinuteLabel,
            incrementado: _horaCompletaConDeltaMinuto(
              1,
            ).minute.toString().padLeft(2, '0'),
            decrementado: _horaCompletaConDeltaMinuto(
              -1,
            ).minute.toString().padLeft(2, '0'),
            style: type.heroTime,
            onTap: () => _ajustarMinuto(1),
            onIncrease: () => _ajustarMinuto(1),
            onDecrease: () => _ajustarMinuto(-1),
            onDragUpdate: _onArrastreMinuto,
          ),
        ],
      ),
    );
  }
}

class _Segmento extends StatelessWidget {
  const _Segmento({
    super.key,
    required this.texto,
    required this.semanticLabel,
    required this.incrementado,
    required this.decrementado,
    required this.style,
    required this.onTap,
    required this.onIncrease,
    required this.onDecrease,
    required this.onDragUpdate,
  });

  final String texto;
  final String semanticLabel;

  /// Text `Semantics.value` becomes after `onIncrease`/`onDecrease` fires.
  /// Flutter requires both whenever a node exposes increase/decrease
  /// actions alongside a `value` (see `SemanticsNode.updateWith`'s
  /// `(value == '') == (increasedValue == '')` assertion).
  final String incrementado;
  final String decrementado;
  final TextStyle? style;
  final VoidCallback onTap;
  final VoidCallback onIncrease;
  final VoidCallback onDecrease;
  final GestureDragUpdateCallback onDragUpdate;

  @override
  Widget build(BuildContext context) {
    // `excludeSemantics: true` + an explicit `onTap` here: without it, the
    // GestureDetector's OWN semantics contribution merges upward and (a)
    // duplicates the digits into `label` (via its child Text's implicit
    // semantics) and (b) auto-exposes scrollUp/scrollDown (Flutter's default
    // accessibility mapping for a registered vertical-drag recognizer) —
    // neither of which this widget wants. Declaring every action explicitly
    // on this one node keeps the exposed contract exactly label/value/
    // increasedValue/decreasedValue/tap/increase/decrease, nothing more.
    return Semantics(
      label: semanticLabel,
      value: texto,
      increasedValue: incrementado,
      decreasedValue: decrementado,
      onTap: onTap,
      onIncrease: onIncrease,
      onDecrease: onDecrease,
      excludeSemantics: true,
      child: GestureDetector(
        behavior: HitTestBehavior.opaque,
        onTap: onTap,
        onVerticalDragUpdate: onDragUpdate,
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 6),
          child: Text(texto, style: style),
        ),
      ),
    );
  }
}