#!/usr/bin/lua

debug_mode = false

--check if version is supported
--why 5.3? utf8 and 64bit support
if (_VERSION ~= "Lua 5.3" ) then
	print "Wrong lua versions"
	print "Supported 5.3 only"
	os.exit(1)
end

--if there is command line arguments then try to read and support them
--get list of files if there is such "-f [FILE] [FILE] ... "
list_ignore_chars = " ：。,.][《》!?:"

arg_files = {}
flag_input_files = false
flag_show_stats = false
flag_compact_stats = false
flag_ignore_chars = false

function reset_flags()
	flag_input_files = false
end

for k,v in ipairs( arg ) do
	if ( v == "-f") then
		flag_input_files = true
	elseif ( v == "-s") then
		reset_flags()
		flag_show_stats = true
	elseif ( v == "-c" ) then
		reset_flags()
		flag_compact_stats = true
	elseif ( v == "-d" ) then
		debug_mode = true
	elseif ( v == "-i") then
		reset_flags()
		flag_ignore_chars = true
	elseif ( v == "-h") then
		reset_flags()
		print(arg[-1]," [FLAGS] [FILE] ")
		print( "-f [FILE] ... - list of file from with is used" )
		print( "-s            - show char stat")
		print( "-c            - show compact char stat")
		print( "-d            - debug mode")
		--print( "-i            - ignore whitespaces,  newlines")
		print( "-h            - just this help")
	else
		--not very nice way to parse all things but still
		if ( (flag_input_files == true) and (v ~= "-f") ) then
			table.insert( arg_files, v )
		end
	end
end

if debug_mode then
	print( arg_files )
	for k,v in pairs(arg_files) do
		print(k,v)
	end
end

function merge_tables( t1, t2 )
	local t = t1
	for k,v in pairs( t2 ) do
		if ( t[k] == nil ) then
			t[k] = v
		elseif ( t[k] ~= nil ) then
			t[k] = t[k] + v
		end
	end
	return t
end

function get_file_stat( filename )
	local hier_table = {}
	--open file
	utf8_file = io.open( filename, "r" )
	if ( utf8_file == nil) then
		print "Couldnot open file"
		os.exit(1)
	end
	for line in utf8_file:lines() do
		for p,c in utf8.codes( line ) do 
			--get characters code and ignore by comparing integer value
			--if flag_ignore_chars == true then
				--print( c, utf8.char(c) )
			--	local ch = utf8.char(c)
				--if string.match( list_ignore_chars, c ) then
			--	if c == 12290 then
			--		print("asdsad")
			--		goto continue
			--	end
			--end
			if hier_table[c] == nil then
				hier_table[c] = 1
			else
				hier_table[c] = hier_table[c] + 1
			end
			::continue::
		end
	end
	io.close( utf8_file )
	return hier_table
end



--read contect in utf8
--l = utf8_file:read("*l")
hier_table = {} 
for k,fn in ipairs(arg_files) do
	local char_stats = get_file_stat( fn )
	hier_table = merge_tables( hier_table, char_stats )
end

hier_table_sorted = {}
for k,v in pairs(hier_table) do
	table.insert( hier_table_sorted, {ch=k,val=v})
end

--sort table chars
function cmpa( a,b )
	if a.val ~= nil and b.val ~= nil then 
		return a.val > b.val
	end
end
table.sort( hier_table_sorted, cmpa )

if ( flag_show_stats == true ) then
	for k,v in pairs(hier_table_sorted) do
		print(utf8.char(v.ch),"=",	v.val)
	end
end

--combined with "-s" should be counter as bug?
if ( flag_compact_stats == true ) then
	local new_val = 0
	for k,v in pairs( hier_table_sorted ) do
		if v.val ~= new_val then 
			new_val = v.val
			print("")
			print(v.val)
			io.write(utf8.char(v.ch)," ")
		else
			io.write(utf8.char(v.ch)," ")
		end
	end
	print("")
end