const _all_defaults = KW[_series_defaults, _plot_defaults, _subplot_defaults]

const _initial_defaults = deepcopy(_all_defaults)
const _initial_axis_defaults = deepcopy(_axis_defaults)

# add defaults for the letter versions
const _axis_defaults_byletter = KW()

function reset_axis_defaults_byletter!()
    for letter in (:x, :y, :z)
        _axis_defaults_byletter[letter] = KW()
        for (k, v) in _axis_defaults
            _axis_defaults_byletter[letter][k] = v
        end
    end
end
reset_axis_defaults_byletter!()

# to be able to reset font sizes to initial values
const _initial_plt_fontsizes =
    Dict(:plot_titlefontsize => _plot_defaults[:plot_titlefontsize])

const _initial_sp_fontsizes = Dict(
    :titlefontsize => _subplot_defaults[:titlefontsize],
    :legend_font_pointsize => _subplot_defaults[:legend_font_pointsize],
    :legend_title_font_pointsize => _subplot_defaults[:legend_title_font_pointsize],
    :annotationfontsize => _subplot_defaults[:annotationfontsize],
    :colorbar_tickfontsize => _subplot_defaults[:colorbar_tickfontsize],
    :colorbar_titlefontsize => _subplot_defaults[:colorbar_titlefontsize],
)

const _initial_ax_fontsizes = Dict(
    :tickfontsize  => _axis_defaults[:tickfontsize],
    :guidefontsize => _axis_defaults[:guidefontsize],
)

const _initial_fontsizes =
    merge(_initial_plt_fontsizes, _initial_sp_fontsizes, _initial_ax_fontsizes)

const _internal_args =
    [:plot_object, :series_plotindex, :markershape_to_add, :letter, :idxfilter]

const _axis_args = sort(union(collect(keys(_axis_defaults))))
const _series_args = sort(union(collect(keys(_series_defaults))))
const _subplot_args = sort(union(collect(keys(_subplot_defaults))))
const _plot_args = sort(union(collect(keys(_plot_defaults))))

const _magic_axis_args = [:axis, :tickfont, :guidefont, :grid, :minorgrid]
const _magic_subplot_args =
    [:title_font, :legend_font, :legend_title_font, :plot_title_font, :colorbar_titlefont]
const _magic_series_args = [:line, :marker, :fill]

const _all_axis_args = sort(union([_axis_args; _magic_axis_args]))
const _all_subplot_args = sort(union([_subplot_args; _magic_subplot_args]))
const _all_series_args = sort(union([_series_args; _magic_series_args]))
const _all_plot_args = _plot_args

const _all_args = sort(union([
    _all_axis_args
    _all_subplot_args
    _all_series_args
    _all_plot_args
]))

# add all pluralized forms to the _keyAliases dict
for arg in _all_args
    add_aliases(arg, makeplural(arg))
end

# fill symbol cache
for letter in (:x, :y, :z)
    _attrsymbolcache[letter] = Dict{Symbol,Symbol}()
    for k in _axis_args
        # populate attribute cache
        lk = Symbol(letter, k)
        _attrsymbolcache[letter][k] = lk
        # allow the underscore version too: xguide or x_guide
        add_aliases(lk, Symbol(letter, "_", k))
    end
    for k in (_magic_axis_args..., :(_discrete_indices))
        _attrsymbolcache[letter][k] = Symbol(letter, k)
    end
end

# add all non_underscored forms to the _keyAliases
add_non_underscore_aliases!(_keyAliases)