import 'package:flutter/material.dart';

import '../../design/number_stepper.dart';
import '../../design/zen_style.dart';
import '../../localization/app_localizations.dart';
import '../models/plan.dart';
import '../plan_labels.dart';

/// Edits a Step, a Superset or a Superset member in a bottom sheet. Every
/// change is handed to [onChanged] right away; there is no separate save.
Future<void> showStepEditor<T>(
  BuildContext context, {
  required String title,
  required T value,
  required ValueChanged<T> onChanged,
}) => showModalBottomSheet<void>(
  context: context,
  isScrollControlled: true,
  showDragHandle: true,
  builder: (context) => _StepEditorSheet<T>(title: title, initial: value, onChanged: onChanged),
);

class _StepEditorSheet<T> extends StatefulWidget {
  const _StepEditorSheet({required this.title, required this.initial, required this.onChanged});

  final String title;
  final T initial;
  final ValueChanged<T> onChanged;

  @override
  State<_StepEditorSheet<T>> createState() => _StepEditorSheetState<T>();
}

class _StepEditorSheetState<T> extends State<_StepEditorSheet<T>> {
  late T _value = widget.initial;

  void _set(Object value) {
    setState(() => _value = value as T);
    widget.onChanged(_value);
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    final text = Theme.of(context).textTheme;
    final value = _value;
    return SafeArea(
      child: Padding(
        padding: const EdgeInsets.fromLTRB(20, 0, 20, 16),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(widget.title, style: text.titleLarge),
            const SizedBox(height: 12),
            ...switch (value) {
              WorkoutStep() => [
                _setsStepper(l10n, value.sets, (n) => _set(value.copyWith(sets: n))),
                _TargetEditor(
                  target: value.target,
                  onChanged: (t) => _set(value.copyWith(target: t)),
                ),
                _WeightEditor(
                  weightKg: value.weightKg,
                  onChanged: (kg) => _set(value.copyWith(weightKg: () => kg)),
                ),
              ],
              SupersetMember() => [
                _TargetEditor(
                  target: value.target,
                  onChanged: (t) => _set(value.copyWith(target: t)),
                ),
                _WeightEditor(
                  weightKg: value.weightKg,
                  onChanged: (kg) => _set(value.copyWith(weightKg: () => kg)),
                ),
              ],
              Superset() => [
                _setsStepper(l10n, value.sets, (n) => _set(value.copyWith(sets: n))),
                SwitchListTile(
                  contentPadding: EdgeInsets.zero,
                  title: Text(l10n.restBetweenLabel, style: text.titleSmall),
                  subtitle: Text(l10n.restBetweenHint),
                  value: value.restBetween,
                  onChanged: (on) => _set(value.copyWith(restBetween: on)),
                ),
              ],
              StretchingStep() => [
                NumberStepper(
                  label: l10n.stepHold,
                  value: l10n.secondsShort(value.holdSeconds),
                  onDecrement: value.holdSeconds > 5
                      ? () => _set(value.copyWith(holdSeconds: value.holdSeconds - 5))
                      : null,
                  onIncrement: value.holdSeconds < 300
                      ? () => _set(value.copyWith(holdSeconds: value.holdSeconds + 5))
                      : null,
                ),
                SwitchListTile(
                  contentPadding: EdgeInsets.zero,
                  title: Text(l10n.stepBothSides, style: text.titleSmall),
                  subtitle: Text(l10n.stepBothSidesHint),
                  value: value.bothSides,
                  onChanged: (on) => _set(value.copyWith(bothSides: on)),
                ),
                NumberStepper(
                  label: l10n.stepRounds,
                  value: '${value.rounds}',
                  onDecrement: value.rounds > 1 ? () => _set(value.copyWith(rounds: value.rounds - 1)) : null,
                  onIncrement: value.rounds < 10 ? () => _set(value.copyWith(rounds: value.rounds + 1)) : null,
                ),
              ],
              _ => const <Widget>[],
            },
            const SizedBox(height: 16),
            SizedBox(
              width: double.infinity,
              height: 48,
              child: FilledButton(onPressed: () => Navigator.of(context).pop(), child: Text(l10n.done)),
            ),
          ],
        ),
      ),
    );
  }

  Widget _setsStepper(AppLocalizations l10n, int sets, ValueChanged<int> onChanged) => NumberStepper(
    label: l10n.stepSets,
    value: '$sets',
    onDecrement: sets > 1 ? () => onChanged(sets - 1) : null,
    onIncrement: sets < 20 ? () => onChanged(sets + 1) : null,
  );
}

/// Reps or time per set, switching between the two with sensible starting values.
class _TargetEditor extends StatelessWidget {
  const _TargetEditor({required this.target, required this.onChanged});

  final WorkoutTarget target;
  final ValueChanged<WorkoutTarget> onChanged;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        const SizedBox(height: 8),
        SegmentedButton<bool>(
          showSelectedIcon: false,
          segments: [
            ButtonSegment(value: false, label: Text(l10n.stepReps)),
            ButtonSegment(value: true, label: Text(l10n.stepTime)),
          ],
          selected: {target.isTimed},
          onSelectionChanged: (timed) =>
              onChanged(timed.single ? const WorkoutTarget.seconds(30) : const WorkoutTarget.reps(10)),
        ),
        if (target.isTimed)
          NumberStepper(
            label: l10n.stepTime,
            value: l10n.secondsShort(target.seconds!),
            onDecrement: target.seconds! > 5 ? () => onChanged(WorkoutTarget.seconds(target.seconds! - 5)) : null,
            onIncrement: target.seconds! < 600 ? () => onChanged(WorkoutTarget.seconds(target.seconds! + 5)) : null,
          )
        else
          NumberStepper(
            label: l10n.stepReps,
            value: '${target.reps}',
            onDecrement: target.reps! > 1 ? () => onChanged(WorkoutTarget.reps(target.reps! - 1)) : null,
            onIncrement: target.reps! < 100 ? () => onChanged(WorkoutTarget.reps(target.reps! + 1)) : null,
          ),
      ],
    );
  }
}

/// An optional target weight in 2.5 kg steps.
class _WeightEditor extends StatelessWidget {
  const _WeightEditor({required this.weightKg, required this.onChanged});

  static const step = 2.5;

  final double? weightKg;
  final ValueChanged<double?> onChanged;

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    final s = ZenStyle.of(context);
    final kg = weightKg;
    if (kg == null) {
      return Padding(
        padding: const EdgeInsets.only(top: 8),
        child: OutlinedButton.icon(
          onPressed: () => onChanged(20),
          icon: const Icon(Icons.add_rounded),
          label: Text(l10n.addWeight),
        ),
      );
    }
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        NumberStepper(
          label: l10n.stepWeight,
          value: l10n.weightKg(kgNumber(kg)),
          onDecrement: kg >= step ? () => onChanged(kg - step) : null,
          onIncrement: kg < 500 ? () => onChanged(kg + step) : null,
        ),
        TextButton(
          onPressed: () => onChanged(null),
          style: TextButton.styleFrom(foregroundColor: s.inkMuted, padding: EdgeInsets.zero),
          child: Text(l10n.removeWeight),
        ),
      ],
    );
  }
}