asciinevrdie/lib/src/core/engine/game_mutations.dart

import 'package:askiineverdie/src/core/model/equipment_slot.dart';
import 'package:askiineverdie/src/core/model/game_state.dart';
import 'package:askiineverdie/src/core/model/pq_config.dart';
import 'package:askiineverdie/src/core/util/pq_logic.dart' as pq_logic;

/// Game state mutations that mirror the original PQ win/reward logic.
class GameMutations {
  const GameMutations(this.config);

  final PqConfig config;

  GameState winEquip(GameState state, int level, EquipmentSlot slot) {
    final rng = state.rng;
    final name = pq_logic.winEquip(config, rng, level, slot);
    final equip = state.equipment;
    final updatedEquip = switch (slot) {
      EquipmentSlot.weapon => equip.copyWith(
        weapon: name,
        bestIndex: EquipmentSlot.weapon.index,
      ),
      EquipmentSlot.shield => equip.copyWith(
        shield: name,
        bestIndex: EquipmentSlot.shield.index,
      ),
      EquipmentSlot.armor => equip.copyWith(
        armor: name,
        bestIndex: EquipmentSlot.armor.index,
      ),
    };
    return state.copyWith(rng: rng, equipment: updatedEquip);
  }

  GameState winStat(GameState state) {
    final updatedStats = pq_logic.winStat(state.stats, state.rng);
    return state.copyWith(rng: state.rng, stats: updatedStats);
  }

  GameState winSpell(GameState state, int wisdom, int level) {
    final result = pq_logic.winSpell(config, state.rng, wisdom, level);
    final parts = result.split('|');
    final name = parts[0];
    final rank = parts.length > 1 ? parts[1] : 'I';

    final spells = [...state.spellBook.spells];
    final index = spells.indexWhere((s) => s.name == name);
    if (index >= 0) {
      spells[index] = spells[index].copyWith(rank: rank);
    } else {
      spells.add(SpellEntry(name: name, rank: rank));
    }

    return state.copyWith(
      rng: state.rng,
      spellBook: state.spellBook.copyWith(spells: spells),
    );
  }

  GameState winItem(GameState state) {
    final rng = state.rng;
    final result = pq_logic.winItem(config, rng, state.inventory.items.length);
    final items = [...state.inventory.items];

    if (result.isEmpty) {
      // Duplicate an existing item if possible.
      if (items.isNotEmpty) {
        final pickIndex = rng.nextInt(items.length);
        final picked = items[pickIndex];
        items[pickIndex] = picked.copyWith(count: picked.count + 1);
      }
    } else {
      final existing = items.indexWhere((e) => e.name == result);
      if (existing >= 0) {
        items[existing] = items[existing].copyWith(
          count: items[existing].count + 1,
        );
      } else {
        items.add(InventoryEntry(name: result, count: 1));
      }
    }

    return state.copyWith(
      rng: rng,
      inventory: state.inventory.copyWith(items: items),
    );
  }
}