eq2go/internal/combat/hit_calculation.go

package combat

import (
	"math"
	"math/rand"
)

// DetermineHit calculates hit result (hit/miss/dodge/parry/block/riposte)
func (cm *CombatManager) DetermineHit(attacker Entity, victim Entity, attackType int8, damageType int8, toHitBonus float32, isCasterSpell bool, spell Spell) int8 {
	// Spell attacks have different hit mechanics
	if isCasterSpell && spell != nil {
		return cm.determineSpellHit(attacker, victim, spell)
	}

	// Calculate base hit chance
	baseHitChance := cm.config.BaseHitChance + toHitBonus

	// Modify hit chance based on level difference
	levelDiff := float32(attacker.GetLevel() - victim.GetLevel())
	hitChance := baseHitChance + (levelDiff * 2.0)

	// Add attacker's accuracy bonuses
	if attackType == AttackTypePrimary || attackType == AttackTypeSecondary {
		// Melee attacks use STR for accuracy
		accuracyBonus := float32(attacker.GetStat(StatSTR)) * 0.05
		hitChance += accuracyBonus
	} else if attackType == AttackTypeRanged {
		// Ranged attacks use AGI for accuracy
		accuracyBonus := float32(attacker.GetStat(StatAGI)) * 0.05
		hitChance += accuracyBonus
	}

	// Cap hit chance
	if hitChance > 95.0 {
		hitChance = 95.0
	} else if hitChance < 5.0 {
		hitChance = 5.0
	}

	// Roll for hit
	hitRoll := rand.Float32() * 100.0
	if hitRoll > hitChance {
		return HitTypeMiss
	}

	// Hit successful - check for defensive actions
	defenseRoll := rand.Float32() * 100.0
	
	// Check for dodge (AGI based)
	dodgeChance := cm.calculateDodgeChance(victim)
	if defenseRoll < dodgeChance {
		return HitTypeDodge
	}
	defenseRoll -= dodgeChance

	// Check for parry (only for frontal attacks with weapon equipped)
	if cm.isFrontalAttack(attacker, victim) && cm.hasWeaponEquipped(victim) {
		parryChance := cm.calculateParryChance(victim)
		if defenseRoll < parryChance {
			// Check for riposte
			riposteChance := parryChance * 0.3 // 30% of parry chance
			if rand.Float32()*100.0 < riposteChance {
				return HitTypeRiposte
			}
			return HitTypeParry
		}
		defenseRoll -= parryChance
	}

	// Check for block (only with shield equipped)
	if cm.hasShieldEquipped(victim) {
		blockChance := cm.calculateBlockChance(victim)
		if defenseRoll < blockChance {
			return HitTypeBlock
		}
		defenseRoll -= blockChance
	}

	// Check for critical hit
	critChance := cm.calculateCritChance(attacker, attackType)
	if rand.Float32()*100.0 < critChance {
		return HitTypeCritical
	}

	// Regular hit
	return HitTypeHit
}

// determineSpellHit calculates hit for spell attacks
func (cm *CombatManager) determineSpellHit(caster Entity, victim Entity, spell Spell) int8 {
	// Spells generally always hit unless resisted
	// Check for spell resistance
	if cm.config.EnableSpellResist {
		resistChance := cm.CalculateSpellResistance(caster, victim, spell)
		if rand.Float32()*100.0 < resistChance {
			return HitTypeMiss
		}
	}

	// Check for spell critical
	critChance := cm.GetSpellCritChance(caster)
	if rand.Float32()*100.0 < critChance {
		return HitTypeCritical
	}

	return HitTypeHit
}

// calculateDodgeChance calculates dodge chance based on AGI and level
func (cm *CombatManager) calculateDodgeChance(entity Entity) float32 {
	baseDodge := cm.config.BaseDodgeChance
	agiBonus := float32(entity.GetStat(StatAGI)) * 0.1
	
	// Level scaling
	levelBonus := float32(entity.GetLevel()) * 0.2
	
	totalDodge := baseDodge + agiBonus + levelBonus
	
	// Cap dodge chance
	if totalDodge > 40.0 {
		totalDodge = 40.0
	} else if totalDodge < 0.0 {
		totalDodge = 0.0
	}
	
	return totalDodge
}

// calculateParryChance calculates parry chance based on weapon skill and STR
func (cm *CombatManager) calculateParryChance(entity Entity) float32 {
	baseParry := cm.config.BaseParryChance
	strBonus := float32(entity.GetStat(StatSTR)) * 0.08
	
	// Level scaling
	levelBonus := float32(entity.GetLevel()) * 0.15
	
	totalParry := baseParry + strBonus + levelBonus
	
	// Cap parry chance
	if totalParry > 35.0 {
		totalParry = 35.0
	} else if totalParry < 0.0 {
		totalParry = 0.0
	}
	
	return totalParry
}

// calculateBlockChance calculates block chance based on shield and STA
func (cm *CombatManager) calculateBlockChance(entity Entity) float32 {
	baseBlock := cm.config.BaseBlockChance
	staBonus := float32(entity.GetStat(StatSTA)) * 0.1
	
	// TODO: Add shield-specific bonuses when item system is integrated
	
	totalBlock := baseBlock + staBonus
	
	// Cap block chance
	if totalBlock > 30.0 {
		totalBlock = 30.0
	} else if totalBlock < 0.0 {
		totalBlock = 0.0
	}
	
	return totalBlock
}

// calculateCritChance calculates critical hit chance
func (cm *CombatManager) calculateCritChance(attacker Entity, attackType int8) float32 {
	baseCrit := cm.config.BaseCriticalChance
	
	var statBonus float32
	switch attackType {
	case AttackTypePrimary, AttackTypeSecondary:
		// Melee crits use STR
		statBonus = float32(attacker.GetStat(StatSTR)) * 0.1
	case AttackTypeRanged:
		// Ranged crits use AGI
		statBonus = float32(attacker.GetStat(StatAGI)) * 0.1
	case AttackTypeSpell:
		// Spell crits use INT
		statBonus = float32(attacker.GetStat(StatINT)) * 0.1
	default:
		statBonus = 0.0
	}
	
	totalCrit := baseCrit + statBonus
	
	// Cap critical chance
	if totalCrit > 50.0 {
		totalCrit = 50.0
	} else if totalCrit < 0.0 {
		totalCrit = 0.0
	}
	
	return totalCrit
}

// isFrontalAttack checks if attack is from the front (for parry eligibility)
func (cm *CombatManager) isFrontalAttack(attacker Entity, victim Entity) bool {
	// Calculate angle between attacker and victim's facing direction
	dx := attacker.GetX() - victim.GetX()
	dz := attacker.GetZ() - victim.GetZ()
	
	if dx == 0 && dz == 0 {
		return true // Same position
	}
	
	// Calculate angle to attacker
	angleToAttacker := math.Atan2(float64(dx), float64(dz)) * 180.0 / math.Pi
	
	// Normalize to 0-360
	if angleToAttacker < 0 {
		angleToAttacker += 360.0
	}
	
	// Get victim's heading (already in degrees 0-360)
	victimHeading := float64(victim.GetHeading())
	
	// Calculate relative angle
	relativeAngle := math.Abs(angleToAttacker - victimHeading)
	if relativeAngle > 180.0 {
		relativeAngle = 360.0 - relativeAngle
	}
	
	// Front arc is 90 degrees (45 degrees either side of facing direction)
	return relativeAngle <= 45.0
}

// hasWeaponEquipped checks if entity has a weapon equipped for parrying
func (cm *CombatManager) hasWeaponEquipped(entity Entity) bool {
	primaryWeapon := cm.itemManager.GetEquippedItem(entity.GetID(), SlotPrimary)
	return primaryWeapon != nil
}

// hasShieldEquipped checks if entity has a shield equipped for blocking
func (cm *CombatManager) hasShieldEquipped(entity Entity) bool {
	secondaryItem := cm.itemManager.GetEquippedItem(entity.GetID(), SlotSecondary)
	if secondaryItem == nil {
		return false
	}
	
	// Check if it's a shield (weapon type 11 = shield)
	return secondaryItem.GetSkillType() == WeaponTypeShield
}

// GetSkillByWeaponType gets the appropriate skill for a weapon type
func (cm *CombatManager) GetSkillByWeaponType(weaponType int8, damageType int8, update bool) int8 {
	// Map weapon types to skill types
	// This would integrate with the skills system
	switch weaponType {
	case WeaponType1HSlash:
		return 0 // 1H Slashing skill
	case WeaponType2HSlash:
		return 1 // 2H Slashing skill
	case WeaponType1HPierce:
		return 2 // 1H Piercing skill
	case WeaponType1HCrush:
		return 3 // 1H Crushing skill
	case WeaponType2HCrush:
		return 4 // 2H Crushing skill
	case WeaponType2HPierce:
		return 5 // 2H Piercing skill
	case WeaponTypeBow:
		return 6 // Bow skill
	case WeaponTypeThrown:
		return 7 // Thrown skill
	case WeaponTypeCrossbow:
		return 8 // Crossbow skill
	case WeaponTypeWand:
		return 9 // Wand skill
	case WeaponTypeFist:
		return 10 // Fist/Unarmed skill
	default:
		return 0 // Default to basic weapon skill
	}
}