using Chickensoft.Collections;

namespace Zennysoft.Game.Implementation.Components;

public class ExperiencePointsComponent
{
  public IAutoProp<int> CurrentExp => _currentExp;

  public IAutoProp<int> ExpToNextLevel => _expToNextLevel;

  public IAutoProp<double> ExpGainRate => _expGainRate;

  public IAutoProp<int> Level => _level;

  private readonly AutoProp<int> _currentExp;

  private readonly AutoProp<int> _expToNextLevel;

  private readonly AutoProp<double> _expGainRate;

  private readonly AutoProp<int> _level;

  public ExperiencePointsComponent()
  {
    var firstLevelExpRequirement = ExpToNextLevelCalculation(1);
    _expToNextLevel = new AutoProp<int>(firstLevelExpRequirement);
    _currentExp = new AutoProp<int>(0);
    _expGainRate = new AutoProp<double>(1.0);
    _level = new AutoProp<int>(1);
  }

  public void Gain(int baseExpGain)
  {
    var modifiedExpGain = baseExpGain * _expGainRate.Value;
    var newCurrentExpTotal = modifiedExpGain + _currentExp.Value;
    while (modifiedExpGain + _currentExp.Value >= _expToNextLevel.Value)
      LevelUp();
    var cappedAmount = Math.Min(baseExpGain + _currentExp.Value, _expToNextLevel.Value);
    _currentExp.OnNext(cappedAmount);
  }

  public void LevelUp()
  {
    _level.OnNext(_level.Value + 1);
    var expToNextLevel = ExpToNextLevelCalculation(_level.Value);
    _currentExp.OnNext(_currentExp.Value - _expToNextLevel.Value);
    _expToNextLevel.OnNext(expToNextLevel);
  }

  private int ExpToNextLevelCalculation(int nextLevel)
  {
    return (int)(6.5 * nextLevel + 4.5 * Math.Pow(nextLevel, 2) + Math.Pow(nextLevel, 3));
  }
}