-- ===================================================================

local enable_moontest =
    minetest.setting_getbool ("enable_moon"     ) or
    minetest.setting_getbool ("enable_moontest" )

codersky       = {}
codersky.name  = nil
codersky.cspec = nil

local pos = { x=0, y=0, z=0 }

-- ===================================================================

local spaceskybox = {
    "sky_pos_y.jpg" ,
    "sky_neg_y.jpg" ,
    "sky_pos_z.jpg" ,
    "sky_neg_z.jpg" ,
    "sky_neg_x.jpg" ,
    "sky_pos_x.jpg" ,
}

local earthskyday = {
    "dayblank.png" ,
    "dayblank.png" ,
    "daycloud.jpg" ,
    "daycloud.jpg" ,
    "daycloud.jpg" ,
    "daycloud.jpg" ,
}

local earthskynight = {
    "earth_night_pos_y.jpg" ,
    "earth_night_neg_y.jpg" ,
    "earth_night_pos_z.jpg" ,
    "earth_night_neg_z.jpg" ,
    "earth_night_neg_x.jpg" ,
    "earth_night_pos_x.jpg" ,
}

-- ===================================================================

local function current_hour()
    return math.mod (math.floor (minetest.get_timeofday() * 24 + 0.5),
        24)
end

-- ===================================================================

local function current_time()
    return math.floor (minetest.get_timeofday() * 24000)
end

-- ===================================================================

codersky.set_sky = function (player, newspec, newname)

    if newspec ~= nil then
        codersky.cspec = { r=newspec.r, g=newspec.g, b=newspec.b }
        newname = nil
    end

    if newname == "skybox" then
--      player:set_sky (nil, "skybox", spaceskybox)
        player:set_sky ({
            clouds = false ,
            base_color = { a=0, r=5, g=5, b=5 } ,
            type = "skybox" ,
            textures = spaceskybox ,
        })
    elseif (newname == "regular") or (codersky.cspec == nil) then
        player:set_sky (nil, "regular", nil)
        codersky.cspec = nil
    else
        player:set_sky (codersky.cspec, "plain", nil)
    end
end

-- ===================================================================

codersky.update_skybox = function (player)
    local name = player:get_player_name()
    local pos  = player:getpos()
    local gpbn = minetest.get_player_by_name (name)

    if not gpbn then return end
    local is_space = upper_realms.is_outer_space (pos.y)

    if  rawget (_G, "earthgen") ~= nil          and
        type (earthgen) == "table"              and
        pos.y >= earthgen.REALM_HEIGHT_MINPOINT and
        pos.y <  earthgen.REALM_HEIGHT_MAXPOINT then

--      local ov = player:get_physics_override()
--      ov.gravity = 1
--      player:set_physics_override (ov)

        local mttime  = current_time()
        local isnight = false

        if (mttime >= 19360) or (mttime <= 5000) then
            isnight = true
        end

        if isnight then
            -- Night runs 7:36pm to 5:00am = about 9.5 hours
            -- 5 lunar positions, so about 2 hours each
            -- Initial position is overhead

            earthskynight [1] = "earth_night_pos_y.jpg"
            earthskynight [5] = "earth_night_neg_x.jpg"

            if (mttime >= 19000) and (mttime < 21000) then
                earthskynight[1] = "earth_night_pos_y_moon_middle.jpg"
            end

            -- 9:00pm to 11:00pm
            if (mttime >= 21000) and (mttime <= 23000) then
                earthskynight [1] = "earth_night_pos_y_moon_upper.jpg"
            end

            -- 11:01pm to 1:00am
            if (mttime > 23000) or (mttime <= 1000) then
                earthskynight [5] = "earth_night_neg_x_moon_upper.jpg"
            end

            -- 1:01am to 3:00am
            if (mttime > 1000) and (mttime <= 3000) then
                earthskynight [5] = "earth_night_neg_x_moon_middle.jpg"
            end

            -- 3:01am on
            if (mttime > 3000) and (mttime <= 6000) then
                earthskynight [5] = "earth_night_neg_x_moon_lower.jpg"
            end
                player:set_sky (nil, "skybox", earthskynight)
        else
            -- Day runs 5:00am to 7:36pm
            -- About 15 hours and 5 positions, so 3 hours each

            -- 5:00am to 8:00am
            earthskyday [1] = "dayblank.png"
            earthskyday [6] = "daycloud.jpg"

            if (mttime > 4000) and (mttime < 8000) then
                earthskyday [6] = "daymoon-lower.jpg"
            end

            if (mttime >= 8000) and (mttime <= 11000) then
                earthskyday [6] = "daymoon-middle.jpg"
            end

            if (mttime > 11000) and (mttime <= 14000) then
                earthskyday [6] = "daymoon-upper.jpg"
            end

            if (mttime > 14000) and (mttime <= 17000) then
                earthskyday [1] = "daymoon-lower.jpg"
            end

            if (mttime > 17000) and (mttime <= 20000) then
                earthskyday [1] = "daymoon-middle.jpg"
            end

            player:set_sky (nil, "skybox", earthskyday)
        end

    elseif is_space then
--      local ov = player:get_physics_override()
--      ov.gravity = 0.2
--      player:set_physics_override (ov)
        player:set_sky (nil, "skybox", spaceskybox)
    else
--      local ov = player:get_physics_override()
--      ov.gravity = 1
--      player:set_physics_override (ov)

        if (pos.y <= 1000) then
            codersky.set_sky (player, nil, nil)
        else
            player:set_sky (nil, "regular", nil)
        end
    end
end

-- ===================================================================

local time = 0

minetest.register_globalstep (function (dtime)
    time = time + dtime
    if time <= 1 then return end

    for _, player in ipairs (minetest.get_connected_players()) do
        time = 0
        codersky.update_skybox (player)
    end
end)

-- ===================================================================

minetest.register_on_leaveplayer (function (player)
    local name = player:get_player_name()
    if name then
        codersky.set_sky (player, nil, "regular", true)
    end
end)