Weapon

local WEAPON = script:FindAncestorByType('Weapon')
local KNOCKBACK_SPEED = 1000

-- Adds impulse to the owner once the attack ability is executed
function OnProjectileSpawned(weapon, projectile)
    local player = weapon.owner

    local projectileDirection = projectile:GetWorldTransform():GetForwardVector()
    local knockbackVector = projectileDirection * player.mass * -KNOCKBACK_SPEED

    -- Push the player away from the spawned projectile
    player:AddImpulse(knockbackVector)
end

WEAPON.projectileSpawnedEvent:Connect(OnProjectileSpawned)

local WEAPON = script:FindAncestorByType('Weapon')

function OnTargetImpactedEvent(weapon, impactData)
    if impactData.targetObject and impactData.targetObject:IsA("Player") then
        weapon.owner.hitPoints = weapon.owner.hitPoints + 2
    end
end

WEAPON.targetImpactedEvent:Connect(OnTargetImpactedEvent)

local WEAPON = script:FindAncestorByType('Weapon')

function Tick()
    WEAPON:Attack()
    Task.Wait(1)
end

local WEAPON = script:FindAncestorByType('Weapon')
local EMPTY_PICKUP_SOUND = script:GetCustomProperty("EmptyPickupSound")

function OnEquipped(weapon, player)
    if (not weapon:HasAmmo()) then
        World.SpawnAsset(EMPTY_PICKUP_SOUND, {position = weapon:GetWorldPosition()})
    end
end

WEAPON.equippedEvent:Connect(OnEquipped)

local WEAPON = script:FindAncestorByType('Weapon')
local RELOAD_ABILITY = script:GetCustomProperty("Reload"):WaitForObject()

local LOCAL_PLAYER = Game.GetLocalPlayer()

function Tick(deltaTime)
    if WEAPON.owner ~= LOCAL_PLAYER then return end

    if WEAPON.currentAmmo == 0 and
    (not WEAPON.isAmmoFinite or LOCAL_PLAYER:GetResource(WEAPON.ammoType) > 0) then

        RELOAD_ABILITY:Activate()

        Task.Wait(
            RELOAD_ABILITY.castPhaseSettings.duration +
            RELOAD_ABILITY.executePhaseSettings.duration +
            RELOAD_ABILITY.recoveryPhaseSettings.duration)
    end
end

local WEAPON = script:FindAncestorByType('Weapon')
local ACTION_NAME = "Aim"
local ACTIVE_STANCE = "1hand_melee_shield_block"

function EnableStance(player)
    if Object.IsValid(player) and player == WEAPON.owner then
        player.animationStance = ACTIVE_STANCE
    end
end

function DisableStance(player)
    if WEAPON and Object.IsValid(player) then
        player.animationStance = WEAPON.animationStance
    end
end

function OnActionPressed(player, actionName)
    if actionName == ACTION_NAME then
        EnableStance(player)
    end
end

function OnActionReleased(player, actionName)
    if actionName == ACTION_NAME then
        DisableStance(player)
    end
end

function OnPlayerDied(player, damage)
    DisableStance(player)
end

function OnEquipped(weapon, player)
    Input.actionPressedEvent:Connect(OnActionPressed)
    Input.actionReleasedEvent:Connect(OnActionReleased)
end

WEAPON.equippedEvent:Connect(OnEquipped)

local WEAPON = script:FindAncestorByType("Weapon")

function ComputeDPS(weapon)
    local dps = 6.2
    while weapon.shotsPerSecond < dps do
        dps = dps / 2
    end

    local burst = math.max(1, weapon.burstCount)
    if burst < weapon.maxAmmo or weapon.maxAmmo <= 0 then
        local burstPeriod = (burst / dps + weapon.attackCooldownDuration)
        dps = burst / burstPeriod
    end

    return dps * weapon.damage * weapon.multiShotCount
end

print("DPS = " .. ComputeDPS(WEAPON))

local WEAPON = script:FindAncestorByType('Weapon')
local SHOOT_ABILITY = script:GetCustomProperty("ShootAbility"):WaitForObject()
local LOW_AMMO_SOUND = WEAPON:GetCustomProperty("LowAmmoSound")
local LOW_AMMO_PERCENTAGE = 0.2

function OnShootExecute(ability)
    if Object.IsValid(WEAPON) and ability.owner == WEAPON.owner then
        if WEAPON.currentAmmo / WEAPON.maxAmmo <= LOW_AMMO_PERCENTAGE then
            if LOW_AMMO_SOUND then
                World.SpawnAsset(LOW_AMMO_SOUND, {position = WEAPON:GetWorldPosition()})
            end
        end
    end
end

SHOOT_ABILITY.executeEvent:Connect(OnShootExecute)

local WEAPON = script:FindAncestorByType('Weapon')

local RELOAD_ABILITY = nil
-- Grabs reload ability from the weapon. Keep trying in case the client hasn't loaded the object yet
while not Object.IsValid(RELOAD_ABILITY) do
    Task.Wait()
    RELOAD_ABILITY = WEAPON:GetAbilities()[2]
end
-- The client script can now keep going, after it has acquired a reference to the reload ability
-- The above could also have been implemented with a :GetCustomProperty(...):WaitForObject()

-- Manually spawn the reloading audio
function SpawnReloadingAudio()
    if WEAPON.reloadSoundId ~= nil then
        World.SpawnAsset(WEAPON.reloadSoundId, {position = WEAPON:GetWorldPosition()})
    end
end

function Tick(deltaTime)

    -- Makes sure that the weapon owner is the local player
    if not Object.IsValid(WEAPON) then return end
    if not WEAPON.owner == Game.GetLocalPlayer() then return end

    if not WEAPON.isAmmoFinite then
        -- Checks when the weapon has empty ammo to reload
        if WEAPON.currentAmmo == 0 then
            SpawnReloadingAudio()
            RELOAD_ABILITY:Activate()
            Task.Wait(RELOAD_ABILITY.castPhaseSettings.duration)
        end
    end
end

local WEAPON = script:FindAncestorByType("Weapon")
local WALL_BANG = script:GetCustomProperty("WallBang") or 2
local DAMAGE_REDUCTION = script:GetCustomProperty("DamageReduction") or 1

if WALL_BANG <= 0 then return end

function OnTargetImpactedEvent(weapon, impactData)
    if not Object.IsValid(weapon) then return end

    local wall = impactData.targetObject
    if not wall or not wall:IsA("StaticMesh") then return end

    -- If the wall hasn't defined the WallBang property it's impenetrable
    local wallBangResistance = wall:GetCustomProperty("WallBang")
    if not wallBangResistance or wallBangResistance >= WALL_BANG then return end

    -- Calculate damage
    local damage = weapon.damage
    if DAMAGE_REDUCTION > 0 then
        local percent = (WALL_BANG - wallBangResistance) / WALL_BANG
        damage = CoreMath.Lerp(0, weapon.damage, percent)

        percent = CoreMath.Clamp(DAMAGE_REDUCTION)
        damage = CoreMath.Lerp(weapon.damage, damage, percent)
    end

    -- Gather info about position and direction of the shot
    local impactPos = impactData:GetHitResult():GetImpactPosition()
    local direction = impactPos - weapon:GetWorldPosition()
    local remainingTravel = weapon.range - impactData.travelDistance

    -- Perhaps do more if the weapon is of hitscan type
    if not weapon.isHitscan then
        if impactData.projectile then
            direction = impactData.projectile:GetVelocity()
        end
    end
    direction = direction:GetNormalized()

    -- Do a series of raycasts to figure out where is the bullet's exit point
    local rayStart = impactPos + direction * 5
    local rayEnd = rayStart + direction * remainingTravel
    local rayParams = {}

    if Object.IsValid(impactData.weaponOwner) and impactData.weaponOwner.team > 0 then
        rayParams.ignoreTeams = weapon.owner.team
    end

    local hit = World.Raycast(rayStart, rayEnd, rayParams)
    if hit then
        rayEnd = rayStart
        rayStart = hit:GetImpactPosition()
    else
        local swapValue = rayEnd
        rayEnd = rayStart
        rayStart = swapValue
    end
    -- The 'hitInverted' is the info about the bullet's exit point
    local hitInverted = World.Raycast(rayStart, rayEnd, rayParams)
    if not hitInverted then return end

    -- Spawn the surface impact VFX on the opposite side of the object
    if weapon.impactSurfaceTemplateId then
        local t = hitInverted:GetTransform()
        SpawnVfx(weapon.impactSurfaceTemplateId, t:GetPosition(), t:GetRotation())
    end

    -- Spawn a new projectile to continue on the trajectory
    local projLength = 5 + weapon.projectileLength + weapon.projectileRadius
    startPos = hitInverted:GetImpactPosition() + direction * projLength
    local projectile = Projectile.Spawn(weapon.projectileTemplateId, startPos, direction)
    -- Copy properties from the weapon to the new projectile
    projectile.owner = impactData.weaponOwner
    projectile.sourceAbility = impactData.sourceAbility
    projectile.speed = weapon.projectileSpeed
    projectile.gravityScale = weapon.projectileGravity
    projectile.drag = weapon.projectileDrag
    projectile.lifeSpan = weapon.projectileLifeSpan * remainingTravel / weapon.range
    projectile.capsuleLength = weapon.projectileLength
    projectile.capsuleRadius = weapon.projectileRadius
    -- If some weapon properties are needed later it's safer to stash them in serverUserData,
    -- because the weapon might be destroyed while the projectile is still in the air:
    projectile.serverUserData.impactSurfaceTemplateId = weapon.impactSurfaceTemplateId
    projectile.serverUserData.impactPlayerTemplateId = weapon.impactPlayerTemplateId
    projectile.serverUserData.impactProjectileTemplateId = weapon.impactProjectileTemplateId
    projectile.serverUserData.direction = direction
    -- Store damage calculation onto the projectile because there may be multiple ones
    projectile.serverUserData.damage = damage

    -- Listen for the impact, to spawn effects and apply damage
    projectile.impactEvent:Connect(OnProjectileImpacted)

    -- Spawn a trail to follow the projectile
    if weapon.trailTemplateId and projectile.speed > 0 then
        local pos = hitInverted:GetImpactPosition()
        local trailLifeSpan = (rayStart - pos).size / projectile.speed
        trailLifeSpan = math.min(projectile.lifeSpan, trailLifeSpan)
        if trailLifeSpan > 0 then
            local rot = Rotation.New(direction, Vector3.UP)
            local trail = World.SpawnAsset(weapon.trailTemplateId, {position = pos, rotation = rot})
            trail:MoveContinuous(direction * projectile.speed)
            trail.lifeSpan = trailLifeSpan
        end
    end
end

function OnProjectileImpacted(projectile, other, hitResult)
    if not Object.IsValid(projectile) then return end

    local impactTemplate = nil

    if other:IsA("Player") then
        -- Construct and apply damage to player
        local dmg = Damage.New(projectile.serverUserData.damage)
        dmg.reason = DamageReason.COMBAT
        dmg:SetHitResult(hitResult)
        dmg.sourceAbility = projectile.sourceAbility
        dmg.sourcePlayer = projectile.owner
        other:ApplyDamage(dmg)

        impactTemplate = projectile.serverUserData.impactPlayerTemplateId
    else
        impactTemplate = projectile.serverUserData.impactSurfaceTemplateId
       end

    -- Spawn impact VFX
    local t = hitResult:GetTransform()
    if impactTemplate then
        SpawnVfx(impactTemplate, t:GetPosition(), t:GetRotation())
    end

    impactTemplate = projectile.serverUserData.impactProjectileTemplateId
    if impactTemplate then
        local rot = Rotation.New(projectile.serverUserData.direction, Vector3.UP)
        SpawnVfx(impactTemplate, t:GetPosition(), rot)
    end
end

function SpawnVfx(template, pos, rot)
    local vfx = World.SpawnAsset(template, {position = pos, rotation = rot})
    if vfx.lifeSpan <= 0 then
        vfx.lifeSpan = 1.2
    end
end

WEAPON.targetImpactedEvent:Connect(OnTargetImpactedEvent)

local WEAPON = script:FindAncestorByType("Weapon")

if WEAPON.muzzleFlashTemplateId == nil then return end

local smartObjects = {}

local muzzleInstance = World.SpawnAsset(WEAPON.muzzleFlashTemplateId, {parent = script})

-- A utility function that runs the same operation on all nodes in an object's hierarchy
function ForEachChild(coreObj, functionToCall)
    functionToCall(coreObj)

    for _, child in ipairs(coreObj:GetChildren()) do
        ForEachChild(child, functionToCall)
    end
end

-- Find all the core objects in the template that have both the Play() and Stop() functions
ForEachChild(muzzleInstance, function(coreObj)
    if coreObj.Play and coreObj.Stop then
        table.insert(smartObjects, coreObj)
        coreObj:Stop()
    end
end)

while true do
    -- Wait between 0 and 1 second
    Task.Wait(math.random())

    -- Play all the effects
    for _, obj in ipairs(smartObjects) do
        obj:Play()
    end

    -- Wait between 0 and 0.3 seconds
    Task.Wait(math.random() * 0.3)

    -- Stop all the effects
    for _, obj in ipairs(smartObjects) do
        obj:Stop()
    end
    -- Repeat...
end

local WEAPON = script:FindAncestorByType('Weapon')

function OnEquipped(equipment, player)
    if WEAPON.currentAmmo == 0 and WEAPON.outOfAmmoSoundId then
        local pos = WEAPON:GetWorldPosition()
        World.SpawnAsset(WEAPON.outOfAmmoSoundId, {position = pos})
    end
end

WEAPON.equippedEvent:Connect(OnEquipped)

local WEAPON_DETAILS_UI = script.parent
local DAMAGE_LABEL = script:GetCustomProperty("DamageLabel"):WaitForObject()
local BOUNCE_UI = script:GetCustomProperty("BounceGroup"):WaitForObject()
local PIERCE_UI = script:GetCustomProperty("PierceGroup"):WaitForObject()

function ShowUI(weapon)
    WEAPON_DETAILS_UI.visibility = Visibility.INHERIT

    -- Damage
    DAMAGE_LABEL.text = "Damage: " .. tostring(weapon.damage)

    -- Bounces? yes/no
    if weapon.projectileBounceCount > 0 then
        BOUNCE_UI.visibility = Visibility.INHERIT
    else
        BOUNCE_UI.visibility = Visibility.FORCE_OFF
    end

    -- Pierces? yes/no
    if weapon.projectilePierceCount > 0 then
        PIERCE_UI.visibility = Visibility.INHERIT
    else
        PIERCE_UI.visibility = Visibility.FORCE_OFF
    end
end

function HideUI()
    WEAPON_DETAILS_UI.visibility = Visibility.FORCE_OFF
end

WeaponClass.AutomaticRifle = 1
WeaponClass.BurstRifle = 2
WeaponClass.Sniper = 3
WeaponClass.Pistol = 4
WeaponClass.Shotgun = 5

function ClassifyWeapon(weapon)
    if weapon.burst > 1 then
        if weapon.shouldBurstStopOnRelease then
            return WeaponClass.AutomaticRifle
        else
            return WeaponClass.BurstRifle
        end
    else
        if weapon.multiShotCount > 1 then
            return WeaponClass.Shotgun

        elseif string.match(weapon:GetAbilities()[1].animation, "pistol") then
            return WeaponClass.Pistol
        else
            return WeaponClass.Sniper
        end
    end
end

local WEAPON = script:FindAncestorByType("Weapon")

if _G.WeaponStudy == nil then
    _G.WeaponStudy = {}
    _G.WeaponStudy.samples = {}

    _G.WeaponStudy.AddSample = function(weapon)
        local key = weapon.name
        if _G.WeaponStudy.samples[key] then return end

        _G.WeaponStudy.samples[key] = {
            spreadMin = weapon.spreadMin,
            spreadMax = weapon.spreadMax,
            spreadAperture = weapon.spreadAperture,
            spreadDecreaseSpeed = weapon.spreadDecreaseSpeed,
            spreadPenaltyPerShot = weapon.spreadPenaltyPerShot,
            damageDealt = 0
        }
    end

    _G.WeaponStudy.ReportDamage = function(weapon, amount)
        local key = weapon.name
        local dmg = _G.WeaponStudy.samples[key].damageDealt
        _G.WeaponStudy.samples[key].damageDealt = dmg + amount
    end
end

_G.WeaponStudy.AddSample(WEAPON)

local GOOD = true
local BAD = false

function CalcStatRating(statName, compareTo, goodOrBad)
    local minValue
    local maxValue
    for weaponName,data in pairs(_G.WeaponStudy.samples) do
        local statValue = data[statName]
        if not minValue or statValue < minValue then
            minValue = statValue
        end
        if not maxValue or statValue > maxValue then
            maxValue = statValue
        end
    end
    if not minValue then
        error("Missing samples")
        return
    end

    local result
    if maxValue == minValue then
        -- Avoid division by zero
        result = 1
    else
        result = (compareTo - minValue) / (maxValue - minValue)
    end

    if goodOrBad == GOOD then
        return result
    end
    return 1 - result
end

function RateMyGun()
    local spreadMinRating = CalcStatRating("spreadMin", WEAPON.spreadMin, BAD)
    local spreadMaxRating = CalcStatRating("spreadMax", WEAPON.spreadMax, BAD)
    local spreadApertureRating = CalcStatRating("spreadAperture", WEAPON.spreadAperture, BAD)
    local spreadDecreaseSpeedRating = CalcStatRating("spreadDecreaseSpeed", WEAPON.spreadDecreaseSpeed, GOOD)
    local spreadPenaltyPerShotRating = CalcStatRating("spreadPenaltyPerShot", WEAPON.spreadPenaltyPerShot, BAD)
    print("")
    print("Rating - " .. WEAPON.name)
    print("  spreadMin: " .. tostring(spreadMinRating))
    print("  spreadMax: " .. tostring(spreadMaxRating))
    print("  spreadAperture: " .. tostring(spreadApertureRating))
    print("  spreadDecreaseSpeed: " .. tostring(spreadDecreaseSpeedRating))
    print("  spreadPenaltyPerShot: " .. tostring(spreadPenaltyPerShotRating))
end

-- We're keeping track of damage dealt here, but additional study is needed to draw conclusions.
-- Plus, this would need to be tested in multiplayer and the data accessed somehow.
function OnTargetImpacted(weapon, impactData)
    if ImpactData.targetObject and ImpactData.targetObject:IsA("Player") then
        -- The damage calculation may change per weapon. This is a generic example
        local damageAmount = weapon.damage

        _G.WeaponStudy.ReportDamage(WEAPON, damageAmount)
    end
end

WEAPON.targetImpactedEvent:Connect(OnTargetImpacted)

-- Rate each gun based on how it measures against all the other ones in the hierarchy.
-- Works best if there are several guns in the scene, with a varying spread of stats.
Task.Wait(1)
RateMyGun()

local WEAPON = script:FindAncestorByType("Weapon")
local MOVING_THRESHOLD = 250

local wasMoving = false
local targetSpreadModifier = 0

function Tick()
    local player = WEAPON.owner
    if not Object.IsValid(player) then return end

    -- Evaluate if the player is moving right now
    local isMovingNow = false
    if player.isJumping then
        isMovingNow = true
    else
        local playerSpeed = player:GetVelocity().size
        if playerSpeed >= MOVING_THRESHOLD then
            isMovingNow = true
        end
    end

    -- Select target spread modifier based on current movement
    if isMovingNow ~= wasMoving then
        if isMovingNow then
            -- Moving
            targetSpreadModifier = WEAPON.spreadMax - WEAPON.spreadMin
        else
            -- Not moving
            targetSpreadModifier = 0
        end
    end
    wasMoving = isMovingNow

    -- Adjust the player spread modify gradually over time
    local t = WEAPON.spreadDecreaseSpeed / 100
    player.spreadModifier = CoreMath.Lerp(player.spreadModifier, targetSpreadModifier, t)
end