local pad = piece "bauplattform"
local nano = piece "flare2"
local transporter = piece "transporter"
local geruest = piece "geruest"

local storedUnits = {}
--storedUnits[1] = "dgheavytank"
--storedUnits[2] = "dgbike"
--storedUnits[3] = "dgheavytank"

local maxUnits = 8
local unloadRadius = 100

function script.Create(unitID)
    Spring.Echo ("spaceport here")
    Hide (geruest)
    Move (transporter, y_axis, 1000)
    Move (pad, y_axis, -200)
    --Hide (transporter)
    StartThread (loop)
end

function script.QueryBuildInfo() return pad end

function script.QueryNanoPiece() return nano end

function script.Activate()
    SetUnitValue(COB.YARD_OPEN, 1)
    SetUnitValue(COB.INBUILDSTANCE, 1)
    SetUnitValue(COB.BUGGER_OFF, 1)
    return 1
end

function script.Deactivate()
    SetUnitValue(COB.YARD_OPEN, 0)
    SetUnitValue(COB.INBUILDSTANCE, 0)
    SetUnitValue(COB.BUGGER_OFF, 0)
    return 0
end

function loop () --for testing
    while (true) do
        Spring.Echo ("que:" .. #Spring.GetFullBuildQueue(unitID) .. "  #storedUnits:" .. #storedUnits)
        Sleep (1000)
    end
end

function script.StartBuilding()
    bID = Spring.GetUnitIsBuilding (unitID)
end

function script.StopBuilding()
    local _,  _,  _, _,  buildprogress = Spring.GetUnitHealth (bID)
    if (buildprogress==1) then
        storeUnit (unitName (bID))
        Spring.DestroyUnit (bID,false,true)
    end
    StartThread (shouldWeDeliver)   --seems not to work without this. maybe buildque only gets cleared once StopBuilding returns?
end

function shouldWeDeliver ()
    Sleep (500)
    if (#storedUnits > 8 or (#Spring.GetFullBuildQueue(unitID)==0 and #storedUnits >0)) then deliverUnits () end
end

function unitName (uID)
    if (not Spring.ValidUnitID (uID)) then return "invalid unitID in unitName()" end
    local udID =Spring.GetUnitDefID(uID)
    local uDef = UnitDefs [udID]
    return uDef.name
end

function deliverUnits ()
    Move (transporter, y_axis, 0, 100)
    WaitForMove (transporter, y_axis)

    if (#storedUnits == 0) then return end
    local x,y,z = Spring.GetUnitPosition (unitID)
    local teamID = Spring.GetUnitTeam (unitID)
    Spring.Echo ("#storedUnits:" .. #storedUnits)
    local step = (math.pi*2)/#storedUnits
    for i=1, #storedUnits do
        dx = x + math.sin (step*i)*unloadRadius
        dz = z + math.cos (step*i)*unloadRadius
        Spring.CreateUnit (storedUnits[i], dx,y,dz, 0, teamID)
        Spring.Echo ("deliver:" .. storedUnits[i])
    end
    storedUnits = {}

    Move (transporter, y_axis, 1000, 100)
end

function storeUnit (unitname)
    storedUnits[#storedUnits+1] = unitname
end

---------------------------------
function script.Killed(recentDamage, maxHealth)
    return 0
end