-- IcyEssentials Core Registration Framework

local storage = minetest.get_mod_storage()

ess = {
	commands = {},
	privileges = {},
	modules = {},
	player_meta = {},
	world_meta = nil,
}

---------------------
-- PLAYER METADATA --
---------------------

-- Load player metadata
local function playerdata_load(name)
	local decoded = minetest.deserialize(storage:get_string(name))
	if not decoded then
		ess.player_meta[name] = {}
		return {}
	end

	ess.player_meta[name] = decoded
	return decoded
end

-- Save player metadata
local function playerdata_save(name)
	if not ess.player_meta[name] then return end
	local encoded = minetest.serialize(ess.player_meta[name])
	storage:set_string(name, encoded)
end

-- Set a player metadata value
function ess.set_player_meta(player, flag, value)
	if not ess.player_meta[player] then
		playerdata_load(player)
	end
	ess.player_meta[player][flag] = value
	playerdata_save(player)
end

-- Get a player's metadata value
function ess.get_player_meta(player, flag)
	if not ess.player_meta[player] then
		playerdata_load(player)
	end
	return ess.player_meta[player][flag]
end

--------------------
-- WORLD METADATA --
--------------------

-- Load player metadata
local function worlddata_load()
	local decoded = minetest.deserialize(storage:get_string("_data"))
	if not decoded then
		ess.world_meta = {}
		return {}
	end

	ess.world_meta = decoded
	return decoded
end

-- Save player metadata
local function worlddata_save()
	if not ess.world_meta then return end
	local encoded = minetest.serialize(ess.world_meta)
	storage:set_string("_data", encoded)
end

-- Set a player metadata value
function ess.set_world_meta(flag, value)
	if not ess.world_meta then worlddata_load() end
	ess.world_meta[flag] = value
	worlddata_save()
end

-- Get a player's metadata value
function ess.get_world_meta(flag)
	if not ess.world_meta then worlddata_load() end
	return ess.world_meta[flag]
end

-------------
-- UTILITY --
-------------

-- Just return a (TODO: translated) string that rejects permission
function ess.reject_permission()
	return false, "You don't have permission to run this command."
end

-- Match a single privilege, but also check ".all" privileges
function ess.priv_match(name, priv)
	local parts = string.split(priv, ".")
	if #parts > 1 then
		if minetest.check_player_privs(name, {[parts[1] .. ".all"] = true}) then
			return true
		end
		if #parts > 2 then
			if minetest.check_player_privs(name, {[parts[1] .. "." .. parts[2] .. ".all"] = true}) then
				return true
			end
		end
	end

	return minetest.check_player_privs(name, {[priv] = true})
end

-- Save a player's position for use with /back
local function save_player_pos(player, commit)
	local pobj = minetest.get_player_by_name(player)
	if not pobj then return end

	local pos = pobj:get_pos()
	if commit then
		ess.set_player_meta(player, "position", minetest.pos_to_string(commit))
	end

	return pos
end

----------------
-- PRIVILEGES --
----------------

local function handle_command_privileges(privileges, description, default)
	local perms = {}
	for perm in pairs(privileges) do
		local parts = string.split(perm, ".")
		if ess.modules[parts[1]] and not ess.privileges[perm] then
			minetest.register_privilege(perm, {
				description = description,
				give_to_singleplayer = default,
			})
			ess.privileges[perm] = true
		end
		perms[perm] = true

		if #parts > 1 then
			for i,p in ipairs(parts) do
				if i == 1 then
					local a = p .. ".all"
					if not ess.privileges[a] then
						minetest.register_privilege(a, {
							description = "icyess all commands in module " .. p,
							give_to_singleplayer = false,
							give_to_admin = false
						})
						ess.privileges[a] = true
					end
					perms[a] = true
				elseif i == 2 then
					local a = parts[1] .. "." .. p .. ".all"
					if not ess.privileges[a] then
						minetest.register_privilege(a, {
							description = "icyess all commands in module " .. p .. " category "..p,
							give_to_singleplayer = false,
							give_to_admin = false
						})
						ess.privileges[a] = true
					end
					perms[a] = true
				end
			end
		end
	end
	perms["ess.all"] = true
	return perms
end

------------------
-- CHATCOMMANDS --
------------------

local function register_chatcommand(command, def)
	if def.privs then
		def.privs = handle_command_privileges(def.privs, def.description, def.default == true)
	end

	local function fn (name, params)
		local privileges_met = false

		-- Check for any of the privileges
		if def.privs then
			for priv in pairs(def.privs) do
				if ess.priv_match(name, priv) then
					privileges_met = true
					break
				end
			end
		else
			privileges_met = true
		end

		if not privileges_met then
			return ess.reject_permission()
		end

		-- If this command is a teleport, save the player position
		local player_pos
		if def.save_player_pos then
			player_pos = save_player_pos(name)
		end

		local splitparams = string.split(params, " ")

		-- Run the chat command function
		local ret,mesg = def.func(name, params, splitparams)

		-- If we saved player position and the command succeeded, commit the last position save
		if ret and player_pos then
			save_player_pos(name, player_pos)
		end

		return ret,mesg
	end

	-- Clean-up the command definition
	local pd = table.copy(def)
	pd.privs = {}
	pd.module = nil
	pd.category = nil
	pd.default = nil
	pd.override = nil
	pd.override_aliases = nil
	pd.save_player_pos = nil
	pd.func = fn

	-- If this command is overriding, check if a command like this already exists and override it
	if def.override and minetest.registered_chatcommands[command] then
		minetest.override_chatcommand(command, pd)
	else
		minetest.register_chatcommand(command, pd)
	end
end

--[[
	IcyEss Module registration
	Registers a module.
]]
function ess.register_module(modname, description)
	ess.modules[modname] = { mod = minetest.get_current_modname(), description = description }
	return {
		register_chatcommand = function (root, cmddef)
			cmddef.module = modname
			return ess.register_chatcommand(root, cmddef)
		end
	}
end

--[[
	IcyEss Command registration
	{
		-- Command aliases (optional)
		-- All of these will be registered as separate commands with the same
		-- privileges and execute function
		aliases = {},

		-- Optional module name, such as "ess-chat" or "protect".
		-- This will be used in privilege generation and grouping.
		module = "ess",

		-- Optional command category, such as "time" or "item".
		-- This will be used in privilege generation and grouping.
		category = "item",

		-- Command privileges (optional)
		-- Set to true to generate privilege based on the command name
		privs = true,

		-- Set privileges a table in order to optionally require one of these privileges
		-- If the privilege starts with the module name, they will automatically be
		-- registered, if they don't already exist.
		privs = {
			"ess.item.repair" = true,
			"ess.item.repair.other" = true,
		},

		-- Command execution (required)
		func = function (name, params),

		-- If command like this exists, do we override it?
		override = false,

		-- If aliases exist, do we override them?
		override_aliases = false,

		-- If this command is given to singleplayer
		default = false,

		-- If this command modifies player's position in some way,
		-- save their current position before running the command
		save_player_pos = false
	}
]]
function ess.register_chatcommand(root, cmddef)
	assert(type(cmddef) == "table", "command definition is not a table")
	assert(cmddef.description ~= nil, "command is missing a description")
	assert(cmddef.func ~= nil, "command definition is missing a function")
	assert(type(cmddef.func) == "function", "command definition is missing a function")

	if ess.commands[root] and not cmddef.override then return end
	if not cmddef.privs and cmddef.privileges then
		cmddef.privs = table.copy(cmddef.privileges)
		cmddef.privileges = nil
	end

	local privs = cmddef.privs
	if not privs then privs = {} end

	-- Set default module
	if not cmddef.module then
		cmddef.module = "ess"
	end

	-- Generate privilege
	if privs == true then
		local a = ""
		if cmddef.module then
			a = a .. cmddef.module .. "."
		end

		if cmddef.category then
			a = a .. cmddef.category .. "."
		end

		privs = {[a .. root] = true}
	end

	-- No privileges required
	local plen = 0
	for _ in pairs(privs) do
		plen = plen + 1
	end
	if plen == 0 then
		privs = nil
	end

	cmddef.privs = privs
	ess.commands[root] = cmddef
	register_chatcommand(root, cmddef)

	if not cmddef.aliases or #cmddef.aliases == 0 then return end
	local aliasdef = table.copy(cmddef)
	aliasdef.func = cmddef.func
	aliasdef.override = cmddef.override_aliases == true
	aliasdef.override_aliases = nil
	aliasdef.description = cmddef.description .. " (alias to "..root..")"

	for _,a in pairs(cmddef.aliases) do
		register_chatcommand(a,aliasdef)
	end
end

function ess.autoregister(list, category)
	for cmd,def in pairs(list) do
		def.category = category
		ess.register_chatcommand(cmd, def)
	end
end