using UnityEngine;
using BumpCombat.Constants;

namespace BumpCombat.Combat
{
    public static class BumpCombatMath
    {
        public static float FrontThreshold => GameplayConstants.Current.Combat.FrontThreshold;
        public static float BackThreshold => GameplayConstants.Current.Combat.BackThreshold;
        public static float PositionDamageMultiplier =>
            GameplayConstants.Current.Combat.PositionDamageMultiplier;
        public static float BackDamageMultiplier =>
            GameplayConstants.Current.Combat.BackDamageMultiplier;

        public static HitSide ClassifySide(Vector2 enemyFacing, Vector2 enemyToPlayer)
        {
            float dot = Vector2.Dot(enemyFacing.normalized, enemyToPlayer.normalized);
            if (dot >= FrontThreshold)
            {
                return HitSide.Front;
            }

            if (dot <= BackThreshold)
            {
                return HitSide.Back;
            }

            return HitSide.Side;
        }

        public static float CalculateLateralOffset(
            Vector2 attackDirection,
            Vector2 attackerPosition,
            Vector2 targetPosition)
        {
            if (attackDirection.sqrMagnitude <= 0f)
            {
                return 0f;
            }

            Vector2 direction = attackDirection.normalized;
            Vector2 perpendicular = new(-direction.y, direction.x);
            return Mathf.Abs(Vector2.Dot(
                targetPosition - attackerPosition,
                perpendicular));
        }

        public static bool IsOffsetHit(
            HitSide side,
            Vector2 attackDirection,
            Vector2 attackerPosition,
            Vector2 targetPosition,
            float minimumLateralOffset)
        {
            return side == HitSide.Front
                && CalculateLateralOffset(
                    attackDirection,
                    attackerPosition,
                    targetPosition) >= minimumLateralOffset;
        }

        public static float ApplySideMultiplier(
            float baseDamage,
            HitSide side,
            bool isOffsetHit = false)
        {
            float multiplier = side == HitSide.Back
                ? BackDamageMultiplier
                : side == HitSide.Side || isOffsetHit
                    ? PositionDamageMultiplier
                    : 1f;
            return DamageCalculator.ApplyMultiplier(baseDamage, multiplier);
        }

        public static bool AppliesPlayerImpactRecoil(
            HitSide side,
            bool isEventEnemy = false)
        {
            return side != HitSide.Back || isEventEnemy;
        }

    }
}