--Minetest
--Copyright (C) 2021-2 x2048
--Copyright (C) 2022-3 rubenwardy
--
--This program is free software; you can redistribute it and/or modify
--it under the terms of the GNU Lesser General Public License as published by
--the Free Software Foundation; either version 2.1 of the License, or
--(at your option) any later version.
--
--This program is distributed in the hope that it will be useful,
--but WITHOUT ANY WARRANTY; without even the implied warranty of
--MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
--GNU Lesser General Public License for more details.
--
--You should have received a copy of the GNU Lesser General Public License along
--with this program; if not, write to the Free Software Foundation, Inc.,
--51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.


local shadow_levels_labels = {
	fgettext("Disabled"),
	fgettext("Very Low"),
	fgettext("Low"),
	fgettext("Medium"),
	fgettext("High"),
	fgettext("Very High"),
	fgettext("Custom"),
}
local PRESET_DISABLED = 1
local PRESET_CUSTOM = #shadow_levels_labels


-- max distance, texture size, texture_32bit, filters, map color
local shadow_presets = {
	[2] = { 62,  512,  true, 0, false },
	[3] = { 93,  1024, true, 0, false },
	[4] = { 140, 2048, true, 1, false },
	[5] = { 210, 4096, true, 2,  true },
	[6] = { 300, 8192, true, 2,  true },
}


local function detect_mapping_idx()
	if not core.settings:get_bool("enable_dynamic_shadows", false) then
		return PRESET_DISABLED
	end

	local shadow_map_max_distance = tonumber(core.settings:get("shadow_map_max_distance"))
	local shadow_map_texture_size = tonumber(core.settings:get("shadow_map_texture_size"))
	local shadow_map_texture_32bit = core.settings:get_bool("shadow_map_texture_32bit", false)
	local shadow_filters = tonumber(core.settings:get("shadow_filters"))
	local shadow_map_color = core.settings:get_bool("shadow_map_color", false)

	for i = 2, 6 do
		local preset = shadow_presets[i]
		if preset[1] == shadow_map_max_distance and
				preset[2] == shadow_map_texture_size and
				preset[3] == shadow_map_texture_32bit and
				preset[4] == shadow_filters and
				preset[5] == shadow_map_color then
			return i
		end
	end
	return PRESET_CUSTOM
end


local function apply_preset(preset)
	if preset then
		core.settings:set_bool("enable_dynamic_shadows", true)
		core.settings:set("shadow_map_max_distance", preset[1])
		core.settings:set("shadow_map_texture_size", preset[2])
		core.settings:set_bool("shadow_map_texture_32bit", preset[3])
		core.settings:set("shadow_filters", preset[4])
		core.settings:set_bool("shadow_map_color", preset[5])
	else
		core.settings:set_bool("enable_dynamic_shadows", false)
	end
end


return {
	query_text = "Shadows",
	requires = {
		shaders = true,
		opengl = true,
	},
	get_formspec = function(self, avail_w)
		local labels = table.copy(shadow_levels_labels)
		local idx = detect_mapping_idx()

		-- Remove "custom" if not already selected
		if idx ~= PRESET_CUSTOM then
			table.remove(labels, PRESET_CUSTOM)
		end

		local fs =
			"label[0,0.2;" .. fgettext("Dynamic shadows") .. "]" ..
			"dropdown[0,0.4;3,0.8;dd_shadows;" .. table.concat(labels, ",") .. ";" .. idx .. ";true]" ..
			"label[0,1.5;" .. core.colorize("#bbb", fgettext("(The game will need to enable shadows as well)")) .. "]"
		return fs, 1.8
	end,
	on_submit = function(self, fields)
		if fields.dd_shadows then
			local old_shadow_level_idx = detect_mapping_idx()
			local shadow_level_idx = tonumber(fields.dd_shadows)
			if shadow_level_idx == nil or shadow_level_idx == old_shadow_level_idx then
				return false
			end

			if shadow_level_idx == PRESET_CUSTOM then
				core.settings:set_bool("enable_dynamic_shadows", true)
				return true
			end

			local preset = shadow_presets[shadow_level_idx]
			apply_preset(preset)
			return true
		end
	end,
}
