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--
--  file:    game_spawn.lua
--  brief:   spawns start unit and sets storage levels
--  author:  Tobi Vollebregt
--
--  Copyright (C) 2010.
--  Licensed under the terms of the GNU GPL, v2 or later.
--
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function gadget:GetInfo()
    return {
        name      = "Spawn",
        desc      = "spawns start unit and sets storage levels",
        author    = "Tobi Vollebregt",
        date      = "January, 2010",
        license   = "GNU GPL, v2 or later",
        layer     = 0,
        enabled   = true  --  loaded by default?
    }
end

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-- synced only
if (not gadgetHandler:IsSyncedCode()) then
    return false
end

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local modOptions = Spring.GetModOptions()


local function GetStartUnit(teamID)
    -- get the team startup info
    local side = select(5, Spring.GetTeamInfo(teamID))
    local startUnit
    if (side == "") then
        -- startscript didn't specify a side for this team
        local sidedata = Spring.GetSideData()
        if (sidedata and #sidedata > 0) then
            startUnit = sidedata[1 + teamID % #sidedata].startUnit
        end
    else
        startUnit = Spring.GetSideData(side)
    end
    return startUnit
end

local function SpawnStartUnit(teamID)
    local startUnit = GetStartUnit(teamID)
    if (startUnit and startUnit ~= "") then
        -- spawn the specified start unit
        local x,y,z = Spring.GetTeamStartPosition(teamID)
        -- snap to 16x16 grid
        x, z = 16*math.floor((x+8)/16), 16*math.floor((z+8)/16)
        y = Spring.GetGroundHeight(x, z)
        -- facing toward map center
        local facing=math.abs(Game.mapSizeX/2 - x) > math.abs(Game.mapSizeZ/2 - z)
            and ((x>Game.mapSizeX/2) and "west" or "east")
            or ((z>Game.mapSizeZ/2) and "north" or "south")
        local unitID = Spring.CreateUnit(startUnit, x, y, z, facing, teamID)
    end

    -- set start resources, either from mod options or custom team keys
    local teamOptions = select(7, Spring.GetTeamInfo(teamID))
    local m = teamOptions.startmetal  or modOptions.startmetal  or 100
    local e = teamOptions.startenergy or modOptions.startenergy or 250

    -- using SetTeamResource to get rid of any existing resource without affecting stats
    -- using AddTeamResource to add starting resource and counting it as income
    if (m and tonumber(m) ~= 0) then
        -- remove the pre-existing storage
        --   must be done after the start unit is spawned,
        --   otherwise the starting resources are lost!
        Spring.SetTeamResource(teamID, "ms", tonumber(m))
        Spring.SetTeamResource(teamID, "m", 0)
        Spring.AddTeamResource(teamID, "m", tonumber(m))
    end
    if (e and tonumber(e) ~= 0) then
        -- remove the pre-existing storage
        --   must be done after the start unit is spawned,
        --   otherwise the starting resources are lost!
        Spring.SetTeamResource(teamID, "es", tonumber(e))
        Spring.SetTeamResource(teamID, "e", 0)
        Spring.AddTeamResource(teamID, "e", tonumber(e))
    end
end


function gadget:GameStart()
    -- only activate if engine didn't already spawn units (compatibility)
    if (#Spring.GetAllUnits() > 0) then
        return
    end

    -- spawn start units
    local gaiaTeamID = Spring.GetGaiaTeamID()
    local teams = Spring.GetTeamList()
    for i = 1,#teams do
        local teamID = teams[i]
        -- don't spawn a start unit for the Gaia team
        if (teamID ~= gaiaTeamID) then
            SpawnStartUnit(teamID)
        end
    end
end