--[[
MIT License

Copyright (c) 2020 Pierre-Yves Rollo

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
]]

local todeg = 180 / math.pi
local torad = math.pi / 180

local contexts = {}

local mod_storage = minetest.get_mod_storage()
local saved_positionings = minetest.deserialize(
	mod_storage:get_string("positionings"), true) or {}

local function get_positionings(player_name)
	return saved_positionings[player_name] or {}
end

local function save_positionings(player_name, player_positionings)
	saved_positionings[player_name] = player_positionings
	mod_storage:set_string("positionings", minetest.serialize(saved_positionings))
end

local function list_positionings(player_name)
	local result = {}
	for name, _ in pairs(get_positionings(player_name)) do
		result[#result + 1] = name
	end
	
	table.sort(result)
	return result
end

local function set_player_positioning(player_name, positioning)
	local player = minetest.get_player_by_name(player_name)
	if not player then
		return
	end
	player:set_pos({
		x = positioning.pos_x,
		y = positioning.pos_y,
		z = positioning.pos_z,
	})
	player:set_look_vertical(positioning.look_v * torad)
	player:set_look_horizontal(positioning.look_h * torad)
	player:set_fov(positioning.fov)
end

local function get_player_positioning(player_name)
	local player = minetest.get_player_by_name(player_name)
	if not player then
		return
	end
	local pos = player:get_pos()
	local fov = player:get_fov()
	if fov == 0 then
		fov = minetest.settings:get("fov")
	end
	return {
			pos_x = pos.x,
			pos_y = pos.y,
			pos_z = pos.z,
			look_v = player:get_look_vertical() * todeg,
			look_h = player:get_look_horizontal() * todeg,
			fov = fov,
		}
end


local positioning_fields = {
	{ name = "pos_x",  label = "X",        step = 0.5, format = ".3f"},
	{ name = "pos_y",  label = "Y",        step = 0.5, format = ".3f"},
	{ name = "pos_z",  label = "Z",        step = 0.5, format = ".3f"},
	{ name = "look_v", label = "Vertical", step = 5.0, format = ".1f", min = -90, max = 90},
	{ name = "look_h", label = "Horiz.",   step = 5.0, format = ".1f"},
	{ name = "fov",    label = "FOV",      step = 5.0, format = ".1f", min = 45, max = 180},
}

local function fields_to_positioning(fields)

	local positioning = {}
	
	for _, field in ipairs(positioning_fields) do
		positioning[field.name] = tonumber(fields[field.name])
		if not positioning[field.name] then
			return
		end
	end
	
	return positioning
end

local function show_formspec(player_name)

	local positioning = get_player_positioning(player_name)
	local context = contexts[player_name] or 
		{ current_positioning = positioning }
	context.positionings = list_positionings(player_name)

	local list = "<current>"
	for _, name in pairs(context.positionings) do
		list = list .. "," .. name or name
	end

	local fs = "formspec_version[3]"..
		"size[15,12]" ..
		"no_prepend[]" ..
		"bgcolor[black;neither;black]" ..

		"container[0,0]"..
		"box[0,0;3,7;#00000040]"..
		"label[0.2,0.4;Saved positionings]"..
		"textlist[0.2,0.7;2.6,3;list;" .. list .. ";" .. (context.selected or 1) .. ";false]" ..
		"button[0.2,4;2.6,0.7;btn_delete;Delete selected]" ..
		"field[0.2,5.3;2.6,0.5;name;Save positioning as;]" .. 
		"button[0.2,6;2.6,0.7;btn_save;Save]" ..
		"container_end[]"..

		"container[2.25,9.8]"..
		"box[0,0;10.5,2.2;#00000040]"..
		"container[0.2,0.4]"..
		"label[0,0;Position:]" ..
		"label[4.5,0;Look:]"

	local x = 0
	for _, field in ipairs(positioning_fields) do
		fs = fs ..
			("field[%.1f,0.5;1.4,0.5;%s;%s;%".. field.format .."]")
				:format(x, field.name, field.label, positioning[field.name]) ..
			("button[%.1f,1.1;0.5,0.5;btn_%s_dec;-]"):format(x, field.name) ..
			("button[%.1f,1.1;0.5,0.5;btn_%s_inc;+]"):format(x + 0.9, field.name)
		x = x + 1.5
	end

	fs = fs ..
		("button[%.1f,0.5;1,0.5;btn_apply;Apply]"):format(x) ..
		"container_end[]" ..
		"container_end[]"

	if context.message then
		fs = fs ..
			"container[3.5,8]"..
			"box[0,0;8,1;#80000040]"..
			"label[1,0.5;" .. context.message .. "]" ..
			"container_end[]"

		context.message = nil
	end
	contexts[player_name] = context
	minetest.show_formspec(player_name, "dev_positioning", fs)
end

minetest.register_on_player_receive_fields(
	function(player, formname, fields)
		if formname ~= "dev_positioning" then
			return
		end

		local player_name = player:get_player_name()

		if fields.quit and not fields.key_enter then
			contexts[player_name] = nil
			minetest.close_formspec(player_name, formname)
			return
		end

		if not minetest.check_player_privs(player_name, {server=true}) then
			minetest.log("error", "Suspicious fields received. Player:" ..
					player_name .. " Formspec:" .. formname .. " (missing privilege).")
			minetest.close_formspec(player_name, formname)
			return
		end

		local context = contexts[player_name]
		
		if not context then
			minetest.log("error", "Suspicious fields received. Player:" .. 
					player_name .. " Formspec:" .. formname .. " (no context found).")
			minetest.close_formspec(player_name, formname)
			return
		end
		
		local positioning = fields_to_positioning(fields)
		if not positioning then
			context.message = "Invalid positioning"
			show_formspec(player_name)
			return
		end

		if fields.list then
			local event = minetest.explode_textlist_event(fields.list)
			if event.type == "CHG" then
				context.selected = event.index
				if context.selected == 1 then
					positioning = context.current_positioning
				else
					local positionings = get_positionings(player_name)
					positioning = positionings[context.positionings[context.selected - 1]]
				end
				if positioning then
					set_player_positioning(player_name, positioning)
					show_formspec(player_name)
				end
			end
			return
		end
			
		if fields.btn_save then
			if not fields.name or fields.name == "" then
				context.message = "Please enter a name"
				show_formspec(player_name)
				return
			end
			-- TODO : Add warning if name exists
			local positionings = get_positionings(player_name)
			positionings[fields.name] = positioning
			save_positionings(player_name, positionings)
			show_formspec(player_name)	
			return
		end

		if fields.btn_delete and context.selected then
			local positionings = get_positionings(player_name)
			if context.positionings[context.selected - 1] then
				positionings[context.positionings[context.selected - 1]] = nil
				save_positionings(player_name, positionings)
				context.selected = 1
				show_formspec(player_name)
			end
			return
		end

		for _, field in ipairs(positioning_fields) do
			local value = math.floor(positioning[field.name] 
					/ field.step + 0.5) * field.step
			if fields["btn_".. field.name .."_dec"] then
				positioning[field.name] = value - field.step
				if field.min and positioning[field.name] < field.min then
					positioning[field.name] = field.min
				end
			end
			if fields["btn_".. field.name .."_inc"] then
				positioning[field.name] = value + field.step
				if field.max and positioning[field.name] > field.max then
					positioning[field.name] = field.max
				end
			end
		end
		set_player_positioning(player_name, positioning)
		show_formspec(player_name)
	end)

minetest.register_chatcommand("devpos",
    {
        params = "",
        description = "Open dev positioning formspec",
        privs = { server=true },
        func = function(player_name, param)
			show_formspec(player_name)
			return true
		end
    })