-- Lesson 24:  Physics.  The finished script, exactly as the lesson ends.

local crates     = {}
local balls      = {}
local aimX       = 0
local aimLeft    = false
local aimRight   = false
local knocks     = 0
local showShapes = false

sceneEnable(true)
sceneSetBackground(16, 18, 26)
sceneSetAmbient(40, 42, 50)

local stone = materialNew()
materialSetColor(stone, 110, 110, 120)
materialSetRoughness(stone, 0.9)

local wood = materialNew()
materialSetColor(wood, 190, 140, 80)
materialSetRoughness(wood, 0.8)

local steel = materialNew()
materialSetColor(steel, 200, 205, 215)
materialSetMetallic(steel, 1)
materialSetRoughness(steel, 0.25)

local floor = nodeNew()
nodeSetMesh(floor, meshBox(16, 0.4, 16), stone)
nodeSetPosition(floor, 0, -0.2, 0)
bodyNew(floor, BODY_STATIC, SHAPE_BOX, 16, 0.4, 16)

local wallMesh = meshBox(16, 1, 0.4)

for _, side in ipairs({ { 0, -8, 0 }, { 0, 8, 0 }, { -8, 0, 90 }, { 8, 0, 90 } }) do
    local wall = nodeNew()
    nodeSetMesh(wall, wallMesh, stone)
    nodeSetPosition(wall, side[1], 0.5, side[2])
    nodeSetRotation(wall, 0, side[3], 0)
    bodyNew(wall, BODY_STATIC, SHAPE_BOX, 16, 1, 0.4)
end

local crateMesh = meshBox(0.8, 0.8, 0.8)


local function crateAt(x, y)
    local crate = nodeNew()

    nodeSetMesh(crate, crateMesh, wood)
    nodeSetPosition(crate, x, y, -2)
    bodyNew(crate, BODY_DYNAMIC, SHAPE_BOX, 0.8, 0.8, 0.8)
    bodySetMass(crate, 4)
    crates[#crates + 1] = crate
end


local function fire()
    local ball = nodeNew()

    nodeSetMesh(ball, meshSphere(0.35, 24), steel)
    nodeSetPosition(ball, aimX, 1.2, 6)
    bodyNew(ball, BODY_DYNAMIC, SHAPE_SPHERE, 0.35)
    bodySetMass(ball, 3)
    bodySetBounce(ball, 0.3)
    bodySetVelocity(ball, 0, 2, -14)
    balls[#balls + 1] = ball
    if #balls > 5 then
        nodeDelete(balls[1])
        table.remove(balls, 1)
    end
end


crateAt(-0.9, 0.4)
crateAt(0, 0.4)
crateAt(0.9, 0.4)
crateAt(-0.45, 1.25)
crateAt(0.45, 1.25)
crateAt(0, 2.1)

local marker = nodeNew()
nodeSetMesh(marker, meshBox(0.7, 0.1, 0.7), steel)
nodeSetPosition(marker, 0, 0.05, 6)

local sun = lightNew(LIGHT_DIRECTIONAL)
nodeSetPosition(sun, -5, 9, 6)
nodeLookAt(sun, 0, 0, -2)
lightSetIntensity(sun, 1.7)
lightSetShadow(sun, true)

local camera = nodeNew()
nodeSetPosition(camera, 0, 4, 11)
nodeLookAt(camera, 0, 1, -2)
cameraSet(camera)
cameraSetPerspective(55, 0.1, 200)


function onCollision(nodeA, nodeB, x, y, z, speed)
    if speed > 4 then
        knocks = knocks + 1
    end
end


function onInputPressed(what)
    if what == SWITCH_BUTTON1 then
        fire()
    elseif what == SWITCH_BUTTON3 then
        showShapes = not showShapes
        if showShapes then
            physicsSetDebug(DEBUG_SHAPES + DEBUG_CONTACTS)
        else
            physicsSetDebug(DEBUG_NONE)
        end
    elseif what == SWITCH_LEFT then
        aimLeft = true
    elseif what == SWITCH_RIGHT then
        aimRight = true
    end
end


function onInputReleased(what)
    if what == SWITCH_LEFT then
        aimLeft = false
    elseif what == SWITCH_RIGHT then
        aimRight = false
    end
end


function onOverlayUpdate()
    local over    = 0
    local settled = true

    if aimLeft then
        aimX = math.max(aimX - 0.08, -5)
    end
    if aimRight then
        aimX = math.min(aimX + 0.08, 5)
    end
    nodeSetPosition(marker, aimX, 0.05, 6)

    for _, crate in ipairs(crates) do
        local pitch, _, roll = nodeGetRotation(crate)

        if math.abs(pitch) > 30 or math.abs(roll) > 30 then
            over = over + 1
        end
        if not bodyIsResting(crate) then
            settled = false
        end
    end

    overlayClear()
    overlayPrint(2, 2, "Arrows aim.  Space fires.  Shift shows the shapes.")
    overlayPrint(2, 4, "knocked over " .. over .. " of " .. #crates .. "   hard hits " .. knocks)
    if settled then
        overlayPrint(2, 6, "everything has settled")
    end
    return OVERLAY_UPDATED
end