minetest_ltool/init.lua

ltool = {}

ltool.playerinfos = {}
ltool.default_edit_fields = {
	axiom="",
	rules_a="",
	rules_b="",
	rules_c="",
	rules_d="",
	trunk="",
	leaves="",
	leaves2="",
	leaves2_chance="",
	fruit="",
	fruit_chance="",
	angle="",
	iterations="",
	random_level="",
	trunk_type="",
	thin_branches="",
	name = "",
}

--[[ This registers the sapling for planting the trees ]]
minetest.register_node("ltool:sapling", {
	description = "custom L-system tree sapling",
	stack_max = 1,
	drawtype = "plantlike",
	tiles = { "ltool_sapling.png" },
	inventory_image = "ltool_sapling.png",
	wield_image = "ltool_sapling.png",
	paramtype = "light",
	paramtype2= "wallmounted",
	walkable = false,
	buildable_to = true,
	groups = { dig_immediate = 3, not_in_creative_inventory=1 },
	drop = "",
	after_place_node = function(pos, placer, itemstack, pointed_thing)
		-- Transfer metadata and start timer
		local nodemeta = minetest.get_meta(pos)
		local itemmeta = itemstack:get_metadata()
		nodemeta:set_string("treedef", itemmeta)
		local timer = minetest.get_node_timer(pos)
		timer:start(5)
	end,
	on_timer = function(pos, elapsed)
		-- Place tree
		local meta = minetest.get_meta(pos)
		local treedef = minetest.deserialize(meta:get_string("treedef"))
		minetest.remove_node(pos)
		minetest.spawn_tree(pos, treedef)
	end,
})

--[[ Load previously saved data from file or initialize an empty tree table ]]
do
	local filepath = minetest.get_worldpath().."/ltool.mt"
	local file = io.open(filepath, "r")
	if(file) then
		local string = file:read()
		io.close(file)
		if(string ~= nil) then
			local savetable = minetest.deserialize(string)
			if(savetable ~= nil) then
				ltool.trees = savetable.trees
				ltool.next_tree_id = savetable.next_tree_id
				ltool.number_of_trees = savetable.number_of_trees
				minetest.log("action", "[ltool] Tree data loaded from "..filepath..".")
			else
				minetest.log("error", "[ltool] Failed to load tree data from "..filepath..".")
			end
		else
			minetest.log("error", "[ltool] Failed to load tree data from "..filepath..".")
		end
	else
		--[[ table of all trees ]]
		ltool.trees = {}
		--[[ helper variables to ensure unique IDs ]]
		ltool.number_of_trees = 0
		ltool.next_tree_id = 1
	end
end

--[[ Adds a tree to the tree table.
	name: The tree’s name.
	author: The author’s / owners’ name
	treedef: The full tree definition, see lua_api.txt

	returns the tree ID of the new tree
]]
function ltool.add_tree(name, author, treedef)
	local id = ltool.next_tree_id
	ltool.trees[id] = {name = name, author = author, treedef = treedef}
	ltool.next_tree_id = ltool.next_tree_id + 1
	ltool.number_of_trees = ltool.number_of_trees + 1
	return id
end

--[[ Removes a tree from the database
	tree_id: ID of the tree to be removed

	returns nil
]]
function ltool.remove_tree(tree_id)
	ltool.trees[tree_id] = nil
	ltool.number_of_trees = ltool.number_of_trees - 1
	for k,v in pairs(ltool.playerinfos) do
		if(v.dbsel ~= nil) then
			if(v.dbsel > ltool.number_of_trees) then
				v.dbsel = ltool.number_of_trees
			end
			if(v.dbsel < 1) then
				v.dbsel = 1
			end
		end
	end
end

ltool.seed = os.time()


--[=[ Here come the functions to build the main formspec.
They do not build the entire formspec ]=]

ltool.loadtreeform = "size[6,7]"

--[[ This is a part of the main formspec: Tab header ]]
function ltool.header(index)
	return "tabheader[0,0;ltool_tab;Edit,Database,Plant,Cheat sheet;"..tostring(index)..";true;false]"
end

--[[ This creates the edit tab of the formspec
	fields: A template used to fill the default values of the formspec. ]]
function ltool.edit(fields)
	if(fields==nil) then
		fields = ltool.default_edit_fields
	end
	local s = function(input)
		if(input==nil) then
			ret = ""
		else
			ret = minetest.formspec_escape(tostring(input))
		end
		return ret
	end
	return ""..
	"field[0.2,-4;6,10;axiom;Axiom;"..s(fields.axiom).."]"..
	"field[0.2,-3.4;6,10;rules_a;Rules set A;"..s(fields.rules_a).."]"..
	"field[0.2,-2.7;6,10;rules_b;Rules set B;"..s(fields.rules_b).."]"..
	"field[0.2,-2.1;6,10;rules_c;Rules set C;"..s(fields.rules_c).."]"..
	"field[0.2,-1.5;6,10;rules_d;Rules set D;"..s(fields.rules_d).."]"..
	"field[0.2,-0.9;3,10;trunk;Trunk node name;"..s(fields.trunk).."]"..
	"field[0.2,-0.3;3,10;leaves;Leaves node name;"..s(fields.leaves).."]"..
	"field[0.2,0.3;3,10;leaves2;Secondary leaves node name;"..s(fields.leaves2).."]"..
	"field[0.2,0.9;3,10;leaves2_chance;Secondary leaves chance (in percent);"..s(fields.leaves2_chance).."]"..
	"field[0.2,1.5;3,10;fruit;Fruit node name;"..s(fields.fruit).."]"..
	"field[0.2,2.1;3,10;fruit_chance;Fruit chance (in percent);"..s(fields.fruit_chance).."]"..

	"field[3.2,-0.9;3,10;angle;Angle (in degrees);"..s(fields.angle).."]"..
	"field[3.2,-0.3;3,10;iterations;Iterations;"..s(fields.iterations).."]"..
	"field[3.2,0.3;3,10;random_level;Randomness level;"..s(fields.random_level).."]"..
	"field[3.2,0.9;3,10;trunk_type;Trunk type (single/double/crossed);"..s(fields.trunk_type).."]"..
	"field[3.2,1.5;3,10;thin_branches;Thin branches? (true/false);"..s(fields.thin_branches).."]"..
	"field[3.2,2.1;3,10;name;Name;"..s(fields.name).."]"..
	"button[0,6.5;2,1;edit_save;Save]"
end

--[[ This creates the database tab of the formspec.
	index: Selected index of the textlist
	playername: To whom the formspec is shown
]]
function ltool.database(index, playername)
	local treestr, tree_ids = ltool.build_tree_textlist(index, playername)
	if(treestr ~= nil) then
		local indexstr
		if(index == nil) then
			indexstr = ""
		else
			indexstr = tostring(index)
		end
		ltool.playerinfos[playername].treeform.database.textlist = tree_ids
		return ""..
		"textlist[0,0;5,6;treelist;"..treestr..";"..tostring(index)..";false]"..
		"button[0,6;2,1;database_rename;Rename tree]"..
		"button[2.1,6;2,1;database_delete;Delete tree]"..
		"button[0,6.5;2,1;database_copy;Copy to editor]"..
		"button[2.1,6.5;2,1;database_update;Reload database]"
	else
		return "label[0,0;The tree database is empty.]"..
		"button[2.1,6.5;2,1;database_update;Reload database]"
	end
end

--[[ This creates the "Plant" tab part of the main formspec ]]
function ltool.plant(tree, fields)
	if(tree ~= nil) then
		if(fields==nil) then
			fields = {}
		end
		local s = function(i)
			if(i==nil) then return ""
			else return tostring(minetest.formspec_escape(i))
			end
		end
		local seed
		if(fields.seed == nil) then
			seed = tostring(ltool.seed)
		else
			seed = fields.seed
		end
		local dropdownindex
		if(fields.plantmode == "Absolute coordinates") then
			dropdownindex = 1
		elseif(fields.plantmode == "Relative coordinates") then
			dropdownindex = 2
		else
			dropdownindex = 1
		end
		return ""..
		"label[0,-0.2;Selected tree: "..minetest.formspec_escape(tree.name).."]"..
		"dropdown[-0.1,0.5;5;plantmode;Absolute coordinates,Relative coordinates;"..dropdownindex.."]"..
		"field[0.2,-2.7;6,10;x;x;"..s(fields.x).."]"..
		"field[0.2,-2.1;6,10;y;y;"..s(fields.y).."]"..
		"field[0.2,-1.5;6,10;z;z;"..s(fields.z).."]"..
		"field[0.2,0;6,10;seed;Seed;"..seed.."]"..
		"button[0,6.5;2,1;plant_plant;Plant]"..
		"button[2.1,6.5;2,1;sapling;Give me a sapling]"
	else
		return "label[0,0;No tree in database selected or database is empty.]"
	end
end


--[[ This creates the cheat sheet tab ]]
function ltool.cheat_sheet()
	return ""..
	"tablecolumns[text;text]"..
	"tableoptions[background=#000000;highlight=#000000;border=false]"..
	"table[0,0;6,7;cheat_sheet;"..
	"Symbol,Action,"..
	"G,Move forward one unit with the pen up,"..
	"F,Move forward one unit with the pen down drawing trunks and branches,"..
	"f,Move forward one unit with the pen down drawing leaves (100% chance),"..
	"T,Move forward one unit with the pen down drawing trunks only,"..
	"R,Move forward one unit with the pen down placing fruit,"..
	"A,Replace with rules set A,"..
	"B,Replace with rules set B,"..
	"C,Replace with rules set C,"..
	"D,Replace with rules set D,"..
	"a,Replace with rules set A\\, chance 90%,"..
	"b,Replace with rules set B\\, chance 80%,"..
	"c,Replace with rules set C\\, chance 70%,"..
	"d,Replace with rules set D\\, chance 60%,"..
	"+,Yaw the turtle right by angle parameter,"..
	"-,Yaw the turtle left by angle parameter,"..
	"&,Pitch the turtle down by angle parameter,"..
	"^,Pitch the turtle up by angle parameter,"..
	"/,Roll the turtle to the right by angle parameter,"..
	"*,Roll the turtle to the left by angle parameter,"..
	"\\[,Save in stack current state info,"..
	"\\],Recover from stack state info]"
end

--[[ creates the content of a textlist which contains all trees.
	index: Selected entry
	playername: To which the main formspec is shown to. Used for highlighting owned trees

	returns (string to be used in the text list, table of tree IDs)
]]
function ltool.build_tree_textlist(index, playername)
	local string = ""
	local colorstring
	if(ltool.number_of_trees == 0) then
		return nil
	end
	local tree_ids = ltool.get_tree_ids()
	for i=1,#tree_ids do
		local tree_id = tree_ids[i]
		local tree = ltool.trees[tree_id]
		if(tree.author == playername) then
			colorstring = "#FFFF00"
		else
			colorstring = ""
		end
		string = string .. colorstring .. tostring(tree_id) .. ": " .. minetest.formspec_escape(tree.name)
		if(i~=#tree_ids) then
			string = string .. ","
		end
	end
	return string, tree_ids
end

--[=[ Here come functions which show formspecs to players ]=]

--[[ Shows the main tree formular to the given player, starting with the "Edit" tab ]]
function ltool.show_treeform(playername)
	local formspec = ltool.loadtreeform..ltool.header(1)..ltool.edit(ltool.playerinfos[playername].treeform.edit.fields)
	minetest.show_formspec(playername, "ltool:treeform_edit", formspec)
end

--[[ spawns a simple dialog formspec to a player ]]
function ltool.show_dialog(playername, formname, message)
	local formspec = "size[6,2;]label[0,0.2;"..message.."]"..
	"button[2,1.5;2,1;okay;OK]"
	minetest.show_formspec(playername, formname, formspec)

end


--[=[ End of formspec-relatec functions ]=]

--[[ This function does a lot of parameter checks and returns (tree, tree_name) on success.
	If ANY parameter check fails, the whole function fails.
	On failure, it returns (nil, <error message string>).]]
function ltool.evaluate_edit_fields(fields)
	local treedef = {}
	-- Validation helper: Checks for invalid characters for the fields “axiom” and the 4 rule sets
	local v = function(str)
		local match = string.match(str, "[^][abcdfABCDFGTR+-/*&^]")
		if(match==nil) then
			return true
		else
			return false
		end
	end
	if(v(fields.axiom) and v(fields.rules_a) and v(fields.rules_b) and v(fields.rules_c) and v(fields.rules_d)) then
		treedef.rules_a = fields.rules_a
		treedef.rules_b = fields.rules_b
		treedef.rules_c = fields.rules_c
		treedef.rules_d = fields.rules_d
		treedef.axiom = fields.axiom
	else
		return nil, "The axiom or one of the rule sets contains at least one invalid character.\nSee the cheat sheet for a list of allowed characters."
	end
	treedef.trunk = fields.trunk
	treedef.leaves = fields.leaves
	treedef.leaves2 = fields.leaves2
	treedef.leaves2_chance = fields.leaves2_chance
	treedef.angle = tonumber(fields.angle)
	if(treedef.angle == nil) then
		return nil, "The field \"Angle\" must contain a number."
	end
	treedef.iterations = tonumber(fields.iterations)
	if(treedef.iterations == nil) then
		return nil, "The field \"Iterations\" must contain a natural number greater or equal to 0."
	elseif(treedef.iterations < 0) then
		return nil, "The field \"Iterations\" must contain a natural number greater or equal to 0."
	end
	treedef.random_level = tonumber(fields.random_level)
	if(treedef.random_level == nil) then
		return nil, "The field \"Randomness level\" must contain a number."
	end
	treedef.fruit = fields.fruit
	treedef.fruit_chance = tonumber(fields.fruit_chance)
	if(treedef.fruit_chance == nil) then
		return nil, "The field \"Fruit chance\" must contain a number."
	elseif(treedef.fruit_chance > 100 or treedef.fruit_chance < 0) then
		return nil, "Fruit chance must be between 0% and 100%."
	end
	if(fields.trunk_type == "single" or fields.trunk_type == "double" or fields.trunk_type == "crossed") then
		treedef.trunk_type = fields.trunk_type
	else
		return nil, "Trunk type must be \"single\", \"double\" or \"crossed\"."
	end
	treedef.thin_branches = fields.thin_branches
	if(fields.thin_branches == "true") then
		treedef.thin_branches = true
	elseif(fields.thin_branches == "false") then
		treedef.thin_branches = false
	else
		return nil, "Field \"Thin branches?\" must be \"true\" or \"false\"."
	end
	local name = fields.name
	if(name == "") then
		return nil, "Name is empty."
	end
	return treedef, name
end


--[=[ Here come several utility functions ]=]

--[[ converts a given tree to field names, as if they were given to a
minetest.register_on_plyer_receive_fields callback function ]]
function ltool.tree_to_fields(tree)
	local s = function(i)
		if(i==nil) then
			return ""
		else
			return tostring(i)
		end
	end
	local fields = {}
	fields.axiom = s(tree.treedef.axiom)
	fields.rules_a = s(tree.treedef.rules_a)
	fields.rules_b = s(tree.treedef.rules_b)
	fields.rules_c = s(tree.treedef.rules_c)
	fields.rules_d = s(tree.treedef.rules_d)
	fields.trunk = s(tree.treedef.trunk)
	fields.leaves = s(tree.treedef.leaves)
	fields.leaves2 = s(tree.treedef.leaves2)
	fields.leaves2_chance = s(tree.treedef.leaves2)
	fields.fruit = s(tree.treedef.leaves2)
	fields.fruit_chance = s(tree.treedef.fruit_chance)
	fields.angle = s(tree.treedef.angle)
	fields.iterations = s(tree.treedef.iterations)
	fields.random_level = s(tree.treedef.random_level)
	fields.trunk_type = s(tree.treedef.trunk_type)
	fields.thin_branches = s(tree.treedef.thin_branches)
	fields.name = s(tree.name)
	return fields
end



-- returns a simple table of all the tree IDs
function ltool.get_tree_ids()
	local ids = {}
	for tree_id, _ in pairs(ltool.trees) do
		table.insert(ids, tree_id)
	end
	return ids
end

--[[ In a table of tree IDs (returned by ltool.get_tree_ids, parameter tree_ids), this function
searches for the first occourance of the value searched_tree_id and returns its index.
This is basically a reverse lookup utility. ]]
function ltool.get_tree_id_index(searched_tree_id, tree_ids)
	for i=1, #tree_ids do
		local table_tree_id = tree_ids[i]
		if(searched_tree_id == table_tree_id) then
			return i
		end
	end
end

-- Returns the selected tree of the given player
function ltool.get_selected_tree(playername)
	local sel = ltool.playerinfos[playername].dbsel 
	if(sel ~= nil) then
		local tree_id = ltool.playerinfos[playername].treeform.database.textlist[sel]
		if(tree_id ~= nil) then
			return ltool.trees[tree_id]
		end
	end
	return nil
end

-- Returns the ID of the selected tree of the given player
function ltool.get_selected_tree_id(playername)
	local sel = ltool.playerinfos[playername].dbsel 
	if(sel ~= nil) then
		return ltool.playerinfos[playername].treeform.database.textlist[sel]
	end
	return nil
end


ltool.treeform = ltool.loadtreeform..ltool.header(1)..ltool.edit()

minetest.register_chatcommand("treeform",
{
	params = "",
	description = "Open L-system tree builder formular.",
	privs = {},
	func = function(playername, param)
		ltool.show_treeform(playername)
	end
})

function ltool.dbsel_to_tree(dbsel, playername)
	return ltool.trees[ltool.playerinfos[playername].treeform.database.textlist[dbsel]]
end

function ltool.save_fields(playername,formname,fields)
	if(formname=="ltool:treeform_edit") then
		ltool.playerinfos[playername].treeform.edit.fields = fields
	elseif(formname=="ltool:treeform_database") then
		ltool.playerinfos[playername].treeform.database.fields = fields
	elseif(formname=="ltool:treeform_plant") then
		ltool.playerinfos[playername].treeform.plant.fields = fields
	end
end

--[=[ Callback functions start here ]=]

function ltool.process_form(player,formname,fields)
	local playername = player:get_player_name()
	local seltree = ltool.get_selected_tree(playername)
	--[[ process clicks on the tab header ]]
	if(formname == "ltool:treeform_edit" or formname == "ltool:treeform_database" or formname == "ltool:treeform_plant" or formname == "ltool:treeform_cheat_sheet") then
		if fields.ltool_tab ~= nil then
			ltool.save_fields(playername, formname, fields)
			local tab = tonumber(fields.ltool_tab)
			local formspec, subformname, contents
			if(tab==1) then
				contents = ltool.edit(ltool.playerinfos[playername].treeform.edit.fields)
				subformname = "edit"
			elseif(tab==2) then
				contents = ltool.database(ltool.playerinfos[playername].dbsel, playername)
				subformname = "database"
			elseif(tab==3) then
				if(ltool.number_of_trees > 0) then
					contents = ltool.plant(seltree, ltool.playerinfos[playername].treeform.plant.fields)
				else
					contents = ltool.plant(nil)
				end
				subformname = "plant"
			elseif(tab==4) then
				contents = ltool.cheat_sheet()
				subformname = "cheat_sheet"
			end
			formspec = ltool.loadtreeform..ltool.header(tab)..contents
			minetest.show_formspec(playername, "ltool:treeform_" .. subformname, formspec)
			return
		end
	end
	--[[ "Plant" tab ]]
	if(formname == "ltool:treeform_plant") then
		if(fields.plant_plant) then
			if(seltree ~= nil) then
				minetest.log("action","[ltool] Planting tree")
				local treedef = seltree.treedef

				local x,y,z = tonumber(fields.x), tonumber(fields.y), tonumber(fields.z)
				local tree_pos
				local fail = function()
					ltool.save_fields(playername, formname, fields)
					ltool.show_dialog(playername, "ltool:treeform_error_badplantfields", "Error: The coordinates must be numbers.")
				end
				if(fields.plantmode == "Absolute coordinates") then
					if(type(x)~="number" or type(y) ~= "number" or type(z) ~= "number") then
						fail()
						return
					end
					tree_pos = {x=fields.x, y=fields.y, z=fields.z}
				elseif(fields.plantmode == "Relative coordinates") then
					if(type(x)~="number" or type(y) ~= "number" or type(z) ~= "number") then
						fail()
						return
					end
					tree_pos = player:getpos()
					tree_pos.x = tree_pos.x + fields.x
					tree_pos.y = tree_pos.y + fields.y
					tree_pos.z = tree_pos.z + fields.z
				else
					minetest.log("error", "[ltool] fields.plantmode = "..tostring(fields.plantmode))
				end
	
				if(tonumber(fields.seed)~=nil) then
					treedef.seed = tonumber(fields.seed)
				end
	
				minetest.spawn_tree(tree_pos, treedef)
	
				treedef.seed = nil
			end
		elseif(fields.sapling) then
			if(seltree ~= nil) then
				local sapling = ItemStack("ltool:sapling")
				-- TODO: Copy the seed into the sapling, too.
				sapling:set_metadata(minetest.serialize(seltree.treedef))
				local leftover = player:get_inventory():add_item("main", sapling)
				if(not leftover:is_empty()) then
					ltool.save_fields(playername, formname, fields)
					ltool.show_dialog(playername, "ltool:treeform_error_sapling", "Error: The sapling could not be given to you. Probably your inventory is full.")
				end
			end
		end
	--[[ "Edit" tab ]]
	elseif(formname == "ltool:treeform_edit") then
		if(fields.edit_save) then
			local param1, param2
			param1, param2 = ltool.evaluate_edit_fields(fields)
		
			if(param1 ~= nil) then
				local treedef = param1
				local name = param2
				local add = true
				for k,v in pairs(ltool.trees) do
					if(v.name == name) then
						ltool.save_fields(playername, formname, fields)
						if(v.author == playername) then
							local formspec = "size[6,2;]label[0,0.2;You already have a tree with this name. Do you want to replace it?]"..
							"button[0,1.5;2,1;replace_yes;Yes]"..
							"button[2,1.5;2,1;replace_no;No]"
							minetest.show_formspec(playername, "ltool:treeform_replace", formspec)
						else
							ltool.show_dialog(playername, "ltool:treeform_error_nameclash", "Error: This name is already taken by someone else.\nPlease choose a different name.")
						end
						add = false
					end
				end
				if(add == true) then
					ltool.add_tree(name, playername, treedef)
				end
			else
				ltool.save_fields(playername, formname, fields)
				local formspec = "size[6,2;]label[0,0.2;Error: The tree definition is invalid.]"..
				"label[0,0.4;"..minetest.formspec_escape(param2).."]"..
				"button[2,1.5;2,1;okay;OK]"
				minetest.show_formspec(playername, "ltool:treeform_error_badtreedef", formspec)
			end
		end
	--[[ "Database" tab ]]
	elseif(formname == "ltool:treeform_database") then
		if(fields.treelist) then
			local event = minetest.explode_textlist_event(fields.treelist)
			if(event.type == "CHG") then
				ltool.playerinfos[playername].dbsel = event.index
				local formspec = ltool.loadtreeform..ltool.header(2)..ltool.database(event.index, playername)
				minetest.show_formspec(playername, "ltool:treeform_database", formspec)
			end
		elseif(fields.database_copy) then
			if(seltree ~= nil) then
				if(ltool.playerinfos[playername] ~= nil) then
					local formspec = ltool.loadtreeform..ltool.header(1)..ltool.edit(ltool.tree_to_fields(seltree))
					minetest.show_formspec(playername, "ltool:treeform_edit", formspec)
				end
			else
				ltool.show_dialog(playername, "ltool:treeform_error_nodbsel", "Error: No tree is selected.")
			end
		elseif(fields.database_update) then
			local formspec = ltool.loadtreeform..ltool.header(2)..ltool.database(ltool.playerinfos[playername].dbsel, playername)
			minetest.show_formspec(playername, "ltool:treeform_database", formspec)

		elseif(fields.database_delete) then
			if(seltree ~= nil) then
				if(playername == seltree.author) then
					local remove_id = ltool.get_selected_tree_id(playername)
					if(remove_id ~= nil) then
						ltool.remove_tree(remove_id)
						local formspec = ltool.loadtreeform..ltool.header(2)..ltool.database(ltool.playerinfos[playername].dbsel, playername)
						minetest.show_formspec(playername, "ltool:treeform_database", formspec)
					end
				else
					ltool.show_dialog(playername, "ltool:treeform_error_delete", "Error: This tree is not your own. You may only delete your own trees.")
				end
			else
				ltool.show_dialog(playername, "ltool:treeform_error_nodbsel", "Error: No tree is selected.")
			end
		elseif(fields.database_rename) then
			if(seltree ~= nil) then
				if(playername == seltree.author) then
					local formspec = "field[newname;New name:;"..minetest.formspec_escape(seltree.name).."]"
					minetest.show_formspec(playername, "ltool:treeform_rename", formspec)
				else
					ltool.show_dialog(playername, "ltool:treeform_error_rename_forbidden", "Error: This tree is not your own. You may only rename your own trees.")
				end
			else
				ltool.show_dialog(playername, "ltool:treeform_error_nodbsel", "Error: No tree is selected.")
			end
		end
	--[[ Process "Do you want to replace this tree?" dialog ]]
	elseif(formname == "ltool:treeform_replace") then
		local editfields = ltool.playerinfos[playername].treeform.edit.fields
		local newtreedef, newname = ltool.evaluate_edit_fields(editfields)
		if(fields.replace_yes) then
			for tree_id,tree in pairs(ltool.trees) do
				if(tree.name == newname) then
					--[[ The old tree is deleted and a
					new one with a new ID is created ]]
					local new_tree_id = ltool.next_tree_id
					ltool.trees[new_tree_id] = {}
					ltool.trees[new_tree_id].treedef = newtreedef
					ltool.trees[new_tree_id].name = newname
					ltool.trees[new_tree_id].author = tree.author
					ltool.next_tree_id = ltool.next_tree_id + 1
					ltool.trees[tree_id] = nil
				end
			end
		end
		local formspec = ltool.loadtreeform..ltool.header(1)..ltool.edit(editfields)
		minetest.show_formspec(playername, "ltool:treeform_edit", formspec)
	--[[ Tree renaming dialog ]]
	elseif(formname == "ltool:treeform_rename") then
		if(fields.newname ~= "") then
			seltree.name = fields.newname
			local formspec = ltool.loadtreeform..ltool.header(2)..ltool.database(ltool.playerinfos[playername].dbsel, playername)
			minetest.show_formspec(playername, "ltool:treeform_database", formspec)
		else
			ltool.show_dialog(playername, "ltool:treeform_error_bad_rename", "Error: This name is empty. The tree name must be non-empty.")
		end
	--[[ Here come various error messages to handle ]]
	elseif(formname == "ltool:treeform_error_badtreedef" or formname == "ltool:treeform_error_nameclash") then
		local formspec = ltool.loadtreeform..ltool.header(1)..ltool.edit(ltool.playerinfos[playername].treeform.edit.fields)
		minetest.show_formspec(playername, "ltool:treeform_edit", formspec)
	elseif(formname == "ltool:treeform_error_badplantfields" or formname == "ltool:treeform_error_sapling") then
		local formspec = ltool.loadtreeform..ltool.header(3)..ltool.plant(seltree, ltool.playerinfos[playername].treeform.plant.fields)
		minetest.show_formspec(playername, "ltool:treeform_plant", formspec)
	elseif(formname == "ltool:treeform_error_delete" or formname == "ltool:treeform_error_rename_forbidden" or formname == "ltool:treeform_error_nodbsel") then
		local formspec = ltool.loadtreeform..ltool.header(2)..ltool.database(ltool.playerinfos[playername].dbsel, playername)
		minetest.show_formspec(playername, "ltool:treeform_database", formspec)
	elseif(formname == "ltool:treeform_error_bad_rename") then
		local formspec = "field[newname;New name:;"..minetest.formspec_escape(seltree.name).."]"
		minetest.show_formspec(playername, "ltool:treeform_rename", formspec)
	end
end

--[[ These 2 functions are basically just table initializions and cleanups ]]
function ltool.leave(player)
	ltool.playerinfos[player:get_player_name()] = nil
end

function ltool.join(player)
	local infotable = {}
	infotable.dbsel = nil
	infotable.treeform = {}
	infotable.treeform.database = {}
	--[[ This table stores a mapping of the textlist IDs in the database formspec and the tree IDs.
	It is updated each time ltool.database is called. ]]
	infotable.treeform.database.textlist = nil
	--[[ the “fields” tables store the values of the input fields of a formspec. It is updated
	whenever the formspec is changed, i.e. on tab change ]]
	infotable.treeform.database.fields = {}
	infotable.treeform.plant = {}
	infotable.treeform.plant.fields = {}
	infotable.treeform.edit = {}
	infotable.treeform.edit.fields = {}
	ltool.playerinfos[player:get_player_name()] = infotable
end

function ltool.save_to_file()
	local savetable = {}
	savetable.trees = ltool.trees
	savetable.number_of_trees = ltool.number_of_trees
	savetable.next_tree_id = ltool.next_tree_id
	local savestring = minetest.serialize(savetable)
	local filepath = minetest.get_worldpath().."/ltool.mt"
	local file = io.open(filepath, "w")
	if(file) then
		file:write(savestring)
		io.close(file)
		minetest.log("action", "[ltool] Tree data saved to "..filepath..".")
	else
		minetest.log("error", "[ltool] Failed to write ltool data to "..filepath".")
	end
	
end

minetest.register_on_player_receive_fields(ltool.process_form)

minetest.register_on_leaveplayer(ltool.leave)

minetest.register_on_joinplayer(ltool.join)

minetest.register_on_shutdown(ltool.save_to_file)