Enemy OOP

local ServerScriptService = game:GetService("ServerScriptService")
local ReplicatedStorage = game:GetService("ReplicatedStorage")

local server = ServerScriptService.Server
local serverModules = server.ServerModules
local CharacterUtil = require(serverModules.CharacterUtil)
local EnemyManager = require(serverModules.EnemyManager)

local sharedModules = ReplicatedStorage.Shared.SharedModules
local AliveCharacters = require(sharedModules.AliveCharacters)


local EnemySwordClass = {}
EnemySwordClass.__index = EnemySwordClass

function EnemySwordClass.new(newInstance, zone, enemyInfo, spawnLocation)
   local self = setmetatable({
      instance = newInstance,
      humanoid = newInstance.Humanoid,
      walkAnim = nil,
      attackAnim = nil,
      rootPart = newInstance.PrimaryPart,
      sword = enemyInfo.sword:Clone(),
      zone = zone,
      players = zone.players,
      enemies = zone.enemies,
      parent = zone.enemyFolder,

      enemyInfo = enemyInfo,
      respawnTime = enemyInfo.respawnTime,
      health = enemyInfo.maxHealth,
      maxHealth = enemyInfo.maxHealth,
      damage = enemyInfo.damage,
      attackRange = enemyInfo.attackRange,
      moveSpeed = enemyInfo.moveSpeed,
      attackDuration = enemyInfo.attackDuration,
      aggroRange = enemyInfo.aggroRange,
      chaseRange = enemyInfo.chaseRange,
      attackers = {},
      spawnLocation = spawnLocation,

      target = nil,
      targetPrimary = nil,
      dead = false,
      retreating = false,
      attacking = false,
      active = true,
   }, EnemySwordClass)
   self:Spawn()
   return self
end

function EnemySwordClass:InChaseRange()
   return (self.rootPart.Position - self.spawnLocation.Position).magnitude < self.chaseRange
end

function EnemySwordClass:InAggroRange(position)
   return (self.rootPart.Position - position).magnitude < self.aggroRange
end

function EnemySwordClass:InAttackRange(position)
   return (self.rootPart.Position - position).magnitude <= self.attackRange
end

function EnemySwordClass:AttackTarget(humanoid, moveSpeed)
   local damage = self.damage
   local attackDuration = self.attackDuration
   local attackAnim = self.attackAnim
   humanoid.WalkSpeed = 0
   attackAnim:Play()
   attackAnim:AdjustSpeed(attackAnim.Length / attackDuration)
   wait(attackDuration)
end

function EnemySwordClass:ChaseTarget(players)
   local humanoid = self.humanoid
   local moveSpeed = self.moveSpeed
   local target = self.target
   local targetPrimary = self.targetPrimary
   local stationary = false
   while self.active and target and targetPrimary and players[target] and AliveCharacters[target] do

      local targetPrimaryPosition = targetPrimary.Position

      if not self:InChaseRange() then
         self:Retreat()
         break
      end

      if self:InAttackRange(targetPrimaryPosition) then
         stationary = true
         self:AttackTarget(humanoid, moveSpeed)
      else
         humanoid:MoveTo(targetPrimaryPosition)
         if stationary then stationary = false humanoid.WalkSpeed = moveSpeed end
      end
      target = self.target
      targetPrimary = self.targetPrimary
      wait()
   end
   self:Retreat()
end

function EnemySwordClass:SetTarget(target)
   local targetCharacter = AliveCharacters[target]

   if targetCharacter then
      self.target = target
      self.targetPrimary = targetCharacter.PrimaryPart
   else
      self.target = nil
      self.targetPrimary = nil
   end
end

function EnemySwordClass:LookForTarget(players)
   for playerName, _ in pairs(players) do
      local character = AliveCharacters[playerName]
      if character and self:InAggroRange(character.PrimaryPart.Position) then
         return playerName
      end
   end
end

function EnemySwordClass:LookForTargetLoop()
   local players = self.players
   spawn(function()
      while self.active and not self.dead and not self.retreating do
         local target = self:LookForTarget(players)
         if target then
            self:SetTarget(target)
            self:ChaseTarget(players)
         end
         wait(.1)
      end
   end)
end

function EnemySwordClass:Retreat()
   local humanoid = self.humanoid
   local moveSpeed = self.moveSpeed
   local maxHealth = self.maxHealth
   local connection
   self.retreating = true
   self:SetTarget(nil)

   connection = humanoid.MoveToFinished:Connect(function(reached)
      -- TODO do actions based on if moveto reached
      if not reached then
         CharacterUtil.TeleportToLocation(self.instance, self.spawnLocation.Position)
         -- teleports enemy if they get stuck on their way back to their spawn
      end
      self.health = maxHealth
      self.retreating = false
      self:LookForTargetLoop()
      connection:Disconnect()
   end)
   humanoid.WalkSpeed = moveSpeed
   humanoid:MoveTo(self.spawnLocation.Position)
end

function EnemySwordClass:TakeDamage(playerName, damage)
   local maxHealth = self.maxHealth
   local origHealth = self.health
   local newHealth = (origHealth - damage)
   if newHealth <= 0 then
      self:Die()
   else
      -- TODO set target
      self:SetTarget(playerName)
      self.health = newHealth
   end
end

function EnemySwordClass:Die()
   self.dead = true
   self:SetTarget(nil)
   EnemyManager:CreateEnemy(self.zone, self.enemyInfo, self.spawnLocation, self.respawnTime)
   self:Destroy()
end

function EnemySwordClass:EquipSword()
   local instance = self.instance
   local sword = self.sword
   sword.Parent = instance
   CharacterUtil.WeldWeaponToHand(instance, sword)
end

function EnemySwordClass:LoadAnimations()
   local humanoid = self.humanoid

   local walkAnim = Instance.new("Animation")
   walkAnim.AnimationId = "http://www.roblox.com/asset/?id=180426354"
   self.walkAnim = humanoid:LoadAnimation(walkAnim)

   local attackAnim = Instance.new("Animation")
   attackAnim.AnimationId = "http://www.roblox.com/asset/?id=4476665450"
   self.attackAnim = humanoid:LoadAnimation(attackAnim)
end

function EnemySwordClass:AnimationController()
   local humanoid = self.humanoid
   local walkAnim = self.walkAnim
   humanoid.Running:Connect(function(speed)
      if not walkAnim.IsPlaying and speed > 0 then
         walkAnim:Play()
      elseif walkAnim.IsPlaying and speed <= 0 then
         walkAnim:Stop()
      end
      wait()
   end)
end

function EnemySwordClass:Spawn()
   local instance = self.instance
   local humanoid = self.humanoid
   instance.Parent = self.parent
   CharacterUtil.TeleportToLocation(instance, self.spawnLocation.Position)
   self:EquipSword()
   self:LoadAnimations()
   self:AnimationController()
   self:LookForTargetLoop()
end

function EnemySwordClass:Destroy()
   local instance = self.instance
   self.active = false
   self.zone.enemies[instance] = nil
   instance:Destroy()
end

return EnemySwordClass