-- new stuff

script.on_init(function ()
	if not global then global = {} end
	if not global.terrains then global.terrains = {} end
	if not global.terrain_names then global.terrain_names = {} end
	if not global.tree_names then global.tree_names = {} end
	if not global.export_must_be_updated then global.export_must_be_updated = false end
end)

script.on_event(defines.events.on_chunk_generated, function (event)
	chunk_generated_handler(event)
end)

function chunk_generated_handler(event)
	--area :: BoundingBox: Area of the chunk
	--surface :: LuaSurface: The surface the chunk is on
	--Area example: {{-2, -3}, {5, 8}} is left_top and right_bottom position
	local area = event.area
	local surface = event.surface
	local entities = surface.find_entities_filtered{area=area, type="tree"} -- don't forget surface!
	if (not entities) or (#entities == 0) then return end
	for i, entity in pairs (entities) do
		search_tiles_by_this_entity_handler(entity)
	end
	--printAll(global.terrains)
	--printAll("We have " .. table_size (global.terrains) .. " terrains")
	if global.export_must_be_updated then
		global.export_must_be_updated = false
		export_iterator()
	end
end

function export_iterator()
	-- reset file
	game.write_file("terrains.txt", "Table of terrains \n", false)
	for i, terrain in pairs (global.terrains) do
		string_to_file(terrain, true)
	end
end

function search_tiles_by_this_entity_handler(entity)
	local tile = entity.surface.get_tile (entity.position)
	add_tree_name_to_terrain_table (global.terrains, entity.name, tile.name)
end

function add_tree_name_to_terrain_table (table, tree_name, terrain_name)
   -- table must be global.terrains or what you use
   if table[terrain_name] then
      local was_added = add_tree_name_to_table_as_last (table[terrain_name].trees, tree_name) -- (table, value)
		if was_added then 
			-- example of process, no writing to the file, but printing
			string_to_file(table[terrain_name], false)
			global.export_must_be_updated = true
		end
   else   
		printAll("New terrain! It is " .. terrain_name)
      table[terrain_name] = {name = terrain_name, trees = {tree_name}}
		-- example of process, no writing to the file, but printing
		string_to_file(table[terrain_name], false)
		global.export_must_be_updated = true
   end
end

function add_tree_name_to_table_as_last (table, value)
	if (not table) or (not value) then return false end
   local cash_i = 0
   for i, v in pairs (table) do
      cash_i = i
      if v == value then
         return false -- we have this already!
      end
   end
   table[cash_i + 1] = value
	return true
end

function table_size (table)
	if (not table) then return 0 end
   local cash_i = 0
   for i, v in pairs (table) do
      cash_i = cash_i + 1
   end
	return cash_i
end

function string_to_file(terrain_tabl, bool)
	--	terrains["grass-medium"] = {name = "grass-medium", trees = {"tree-04"}}
	local prefix = 'terrains["' .. terrain_tabl.name .. '"]'
	local suffix = serpent.block(terrain_tabl, {comment = false})
	local text_to_export = prefix .. " = " .. suffix .. ", \n"
	if not bool then printAll(text_to_export) end
	if bool then game.write_file("terrains.txt", text_to_export, true) end
end

function printAll(text)
	if type(text) == "table" then text = serpent.block(text, {comment = false}) end
	for player_index, player in pairs (game.players) do game.players[player_index].print (text) end
end