local min = math.min
local max = math.max
local cube
local physics_ball
local character
local ball
local camera

local vx = 0.0
local vy = 0.0
local vz = 0.0

local character_move_vec = couch.Vector3(0.0, 0.0, 0.0)

local ballvy = -1.0

local cam_rot_x = 0.0
local cam_rot_y = 0.0

local SPEED = 30

local WHITE = couch.Vector3(1.0, 1.0, 1.0)
local RED = couch.Vector3(1.0, 0.0, 0.0)
local BLUE = couch.Vector3(0.0, 0.0, 1.0)

local light

function init()
   local material
   local transform
   
   camera = couch.Camera()
   camera:MakeCurrent()
   camera:Translate(couch.Vector3(0.0, 0.0, 10.0))

   local light = couch.DirectionalLight()
   light.direction = couch.Vector3(0.0, -1.0, -1.0)
   light.color = couch.Vector3(1.0, 1.0, 1.0)
   light.ambient = 0.2
   light.diffuse = 1.0
   light.specular = 0.1
   couch.Node.GetRoot():AddChild(light:Instance())

   local skybox = couch.Skybox.FromFiles(
      "skybox/px.png",
      "skybox/nx.png",
      "skybox/py.png",
      "skybox/ny.png",
      "skybox/pz.png",
      "skybox/nz.png"
   )
   couch.Node.GetRoot():AddChild(skybox:Instance())

   local physics_ball_prefab = couch.Rigidbody()
   local physics_ball_mesh = couch.Mesh.FromFile("ball.obj")
   material = physics_ball_mesh:GetMaterial(0)
   material.ambient = BLUE
   material.diffuse = BLUE
   physics_ball_mesh:SetMaterial(0, material)
   physics_ball_prefab:AddChild(physics_ball_mesh);
   physics_ball_prefab:Translate(couch.Vector3(0.0, 30.0, -10.0))
   physics_ball = physics_ball_prefab:Instance()
   couch.Node.GetRoot():AddChild(physics_ball)

   make_ground()

   local character_prefab = couch.Mesh.FromFile("capsule.obj")
   material = character_prefab:GetMaterial(0)
   material.ambient = BLUE
   material.diffuse = BLUE
   material.specular = WHITE * 0.1
   character_prefab:SetMaterial(0, material)
   local character_body = couch.Rigidbody()
   character_body:SetMass(1.0)
   character_body:SetCollisionShape(couch.CapsuleCollisionShape(1.0, 1.0))
   character_body:SetCharacter(true)
   character_body:AddChild(character_prefab)
   character_body:Translate(couch.Vector3(0.0, 3.0, 0.0))
   character = character_body:Instance()
   couch.Node.GetRoot():AddChild(character)

   local cube_prefab = couch.Mesh.FromFile("cube.obj")
   material = cube_prefab:GetMaterial(0)
   material.ambient = RED
   material.diffuse = RED
   cube_prefab:SetMaterial(0, material)
   local orbiter = couch.Mesh.FromFile("ball.obj")
   orbiter:UniformScale(0.25);
   orbiter:Translate(couch.Vector3(1.0, 0.0, 0.0))
   cube_prefab:AddChild(orbiter)
   cube = cube_prefab:Instance()
   couch.Node.GetRoot():AddChild(cube)
   
   local ball_prefab = couch.Mesh.FromFile("ball.obj")
   material = ball_prefab:GetMaterial(0)
   ball_prefab:SetMaterial(0, material)
   ball = ball_prefab:Instance()
   couch.Node.GetRoot():AddChild(ball)

   ball:Translate(couch.Vector3(0.0, 3.0, 0.0))

   local trough_prefab = couch.TexturedMesh("trough.obj", "wood_lowres.png")
   trough = trough_prefab:Instance()
   couch.Node.GetRoot():AddChild(trough)
   trough:Translate(couch.Vector3(10.0, 0.0, 0.0))

   local scaffold_prefab = couch.TexturedMesh("scaffold.obj", "grate_floor_lowres.png", "railing.png")
   local scaffold = scaffold_prefab:Instance()
   material = scaffold:GetMaterial(0)
   material.alphaScissor = 0.9
   scaffold:SetMaterial(0, material)
   material = scaffold:GetMaterial(1)
   material.cullBack = false
   scaffold:SetMaterial(1, material)
   material = scaffold:GetMaterial(1)
   material.alphaScissor = 0.1
   scaffold:SetMaterial(1, material)
   couch.Node.GetRoot():AddChild(scaffold)
   scaffold:Translate(couch.Vector3(-3.0, 3.0, 0.0))

   local barn_prefab = couch.TexturedMesh("barn.obj", "paintedwood.jpg", "barnroof_lowres.png", "wood_lowres.png")
   local barn = barn_prefab:Instance()
   material = barn:GetMaterial(0)
   material.cullBack = false
   barn:SetMaterial(0, material)
   material = barn:GetMaterial(1)
   material.cullBack = false
   barn:SetMaterial(1, material)
   couch.Node.GetRoot():AddChild(barn)
   barn:Translate(couch.Vector3(-15.0, 0.0, 0.0))
end

function update(delta)
   local move_vec = couch.Vector3()
   local camera_transform = camera:GetTransform()
   move_vec = camera_transform.position + camera_transform:Forward() * delta * vz * SPEED
   move_vec = move_vec + camera_transform:Right() * delta * vx * SPEED
   move_vec = move_vec + camera_transform:Up() * delta * vy * SPEED
   camera_transform.position = move_vec
   
   camera_transform.rotation.y = camera_transform.rotation.y - cam_rot_x * delta
   cam_rot_x = 0.0
   camera_transform.rotation.x = camera_transform.rotation.x - cam_rot_y * delta
   camera_transform.rotation.x = min(max(camera_transform.rotation.x, -3.14 / 2.0), 3.14 / 2.0)
   cam_rot_y = 0.0

   camera:SetTransform(camera_transform)

   local loc = ball:GetTransform().position
   if loc.y > 4.0 then
      ballvy = -1.0
   elseif loc.y < 2.0 then
      ballvy = 1.0
   end
   ball:Translate(couch.Vector3(ballvy * delta, 0.0, 0.0))

   cube:RotateY(2.0 * delta)
   cube:RotateZ(1.0 * delta)

   character:ApplyForce(character_move_vec * 10.0)
end

function action_dir(key, action, pos, neg, curr)
   if key == pos and action == couch.ACTION_PRESS then
      return 1.0
   elseif key == neg and action == couch.ACTION_PRESS then
      return -1.0
   elseif (key == pos or key == neg) and action == couch.ACTION_RELEASE then
      return 0.0
   else
      return curr
   end
end

function onkey(key, code, action, mod)
   vz = action_dir(key, action, couch.KEY_W, couch.KEY_S, vz)
   vx = action_dir(key, action, couch.KEY_D, couch.KEY_A, vx)
   vy = action_dir(key, action, couch.KEY_SPACE, couch.KEY_LEFT_CONTROL, vy)
   
   if key == couch.KEY_J and action == couch.ACTION_PRESS then
      physics_ball:ApplyImpulse(couch.Vector3(0.0, 1.0, 0.0) * 10)
   end

   character_move_vec.z = action_dir(key, action, couch.KEY_DOWN, couch.KEY_UP, character_move_vec.z)
end

function onmousemotion(_, _, relx, rely)
   cam_rot_x = relx
   cam_rot_y = rely
end

function make_ground()
   local ground_prefab = couch.TexturedMesh("ground.obj", "grass_lowres.png")
   
   local ground_prefab_transform = ground_prefab:GetTransform()
   ground_prefab_transform.position = couch.Vector3(0.0, -2.0, 0.0)
   ground_prefab_transform.scale = couch.Vector3(3.0, 1.0, 3.0)
   ground_prefab:SetTransform(ground_prefab_transform)

   ground = couch.Spatial():Instance()
   couch.Node.GetRoot():AddChild(ground)

   -- Add a collisionshape
   local ground_shape_prefab = couch.Rigidbody()
   ground_shape_prefab:SetMass(0.0)
   ground_shape_prefab:SetCollisionShape(couch.BoxCollisionShape(180.0, 1.0, 180.0))
   ground_shape_prefab:Translate(couch.Vector3(0.0, -2.5, 0.0))
   ground:AddChild(ground_shape_prefab:Instance())

   for x = -20, 20, 1 do
      for z = -20, 20, 1 do
	 local piece = ground_prefab:Instance()
	 piece:Translate(couch.Vector3(6.0 * x, -2.0, 6.0 * z))
	 ground:AddChild(piece)
      end
   end
end