using System.Collections.Generic;

public static class ModifierPipeline
{
    // Application order (explicit):
    //   1. Category-level additive   (AddPerDieValue)
    //   2. Category-level multiplicative (MultiplyPerDieValue)
    //   3. Final-score additive      (AddFlatToFinalScore)
    //   4. Final-score multiplicative (MultiplyFinalScore)

    public static void Apply(
        IReadOnlyList<ModifierData> activeModifiers,
        ref ScoreResult result,
        ModifierScope currentScope)
    {
        if (activeModifiers == null) return;

        // Pass 1: Category-level additive
        for (int i = 0; i < activeModifiers.Count; i++)
        {
            var mod = activeModifiers[i];
            if (!ShouldApply(mod, ref result, currentScope)) continue;
            if (mod.IsCategoryLevel && mod.IsAdditive)
                ModifierEffect.Apply(mod, ref result);
        }

        // Pass 2: Category-level multiplicative
        for (int i = 0; i < activeModifiers.Count; i++)
        {
            var mod = activeModifiers[i];
            if (!ShouldApply(mod, ref result, currentScope)) continue;
            if (mod.IsCategoryLevel && mod.IsMultiplicative)
                ModifierEffect.Apply(mod, ref result);
        }

        // Pass 3: Final-score additive
        for (int i = 0; i < activeModifiers.Count; i++)
        {
            var mod = activeModifiers[i];
            if (!ShouldApply(mod, ref result, currentScope)) continue;
            if (mod.IsFinalScoreLevel && mod.IsAdditive)
                ModifierEffect.Apply(mod, ref result);
        }

        // Pass 4: Final-score multiplicative
        for (int i = 0; i < activeModifiers.Count; i++)
        {
            var mod = activeModifiers[i];
            if (!ShouldApply(mod, ref result, currentScope)) continue;
            if (mod.IsFinalScoreLevel && mod.IsMultiplicative)
                ModifierEffect.Apply(mod, ref result);
        }
    }

    private static bool ShouldApply(ModifierData mod, ref ScoreResult result, ModifierScope currentScope)
    {
        if (mod == null) return false;
        if (mod.Scope != currentScope) return false;
        if (mod.Target.HasCategoryFilter && mod.Target.TargetCategory != result.Category) return false;
        return true;
    }
}