Help a beginner with reloading colors on colorscheme change [almost done]

[oredaze]

I am trying to wrap my head around this code, but it (the head) is exploding :)
I am not a programmer, barely know basics.
Have almost the whole heirline done, except this. The following works, but the mode colors need to refresh on colorscheme change like the first ones do. I just don't know how to place them in the setup_colors function, which does the refreshing at the bottom. I tired everything, but these metatables and metafunctions are too complicated for me.

local utils = require('heirline.utils')
local get_hl = utils.get_highlight

local function setup_colors()
    return {
        filename = get_hl('Normal').fg,
        modified = get_hl('Number').fg,
        workdir = get_hl('Tag').fg,
        filetype = get_hl('Type').fg,
        blablabla
        blablabla
    }
end

-- Mode colors
do
    local mode_colors = {
        normal = get_hl('StatusLine').fg,
        insert = get_hl('Number').fg,
        visual = get_hl('Type').fg,
        blablabla
        blablabla
    }
    Mode = setmetatable({
        normal = { fg = "statusline_bg" }
    }, {
        __index = function(_, mode)
            return {
                fg = "statusline_bg",
                bg = mode_colors[mode],
                bold = true
            }
        end
    })
end


require("heirline").load_colors(setup_colors)
vim.api.nvim_create_augroup("Heirline", { clear = true })
vim.api.nvim_create_autocmd("ColorScheme", {
    callback = function()
        utils.on_colorscheme(setup_colors)
    end,
    group = "Heirline",
})

blablabla is just the rest of the colors...

The colors adapt to my colorscheme, so it's very nice.
If you want I can upload the whole thing, but it almost looks like the cookbook.