Cart = {}

local sizeX, sizeY = CartSprite:getSize()
local size = { x = sizeX, y = sizeY * 0.75 }
local secOver90 = 0

filteredSystem("launchedByCrank", { launchedByCrank = T.marker, crankState = T.CrankState, baseVelocity = T.XyPair }, function(e, dt, system)
    local change = math.abs(e.crankState.changeInLastHalfSecond)
    if change > 90 then
        secOver90 = secOver90 + dt
    end

    if secOver90 > 0.05 then
        secOver90 = 0
        local launchPower = change - 40
        print("Launch power: " .. launchPower)
        e.launchedByCrank = nil
        e.crankState = nil
        e.velocity = { x = launchPower * e.baseVelocity.x, y = launchPower * e.baseVelocity.y }
        system.world:addEntity(e)
    end
end)

cartSystem = filteredSystem("cart", { isCart = T.marker })

function Cart.reset(o)
    o.launchedByCrank = T.marker
    o.isCart = T.marker
    o.position = {
        x = 20,
        y = 50,
    }
    o.velocity = nil
    o.size = size
    o.canBeBounced = {
        flat = { x = 0, y = 0 },
        mult = { x = 1, y = 1 },
    }
    o.canCollideWith = 1 | 4
    o.mass = 1
    o.drawAsSprite = CartSprite
    o.focusPriority = 0

    ---@param world World
    function o:spawnEntitiesWhenStopped(world)
        -- it'd be funny if the cart fully just exploded instead
        self.velocity = { x = 300, y = 0 }
        self.canCollideWith = 4
        world:addEntity({
            roundAction = "end",
            position = {
                x = self.position.x,
                y = self.position.y,
            },
        })
        -- Focus on the center, where the cart stopped
        world:addEntity({
            position = { x = self.position.x, y = self.position.y },
            focusPriority = 1,
            removeAtRoundStart = true,
        })
    end

    return o
end

function Cart.new()
    return setmetatable(
        Cart.reset({
            baseVelocity = {
                x = 2,
                y = -1,
            },
        }),
        { __index = Cart }
    )
end