lua repl using ffi, windows isn't finished/working

repl.lua

local ffi = require("ffi")

local start
local stop
local read

if jit.os == "Linux" then

	ffi.cdef([[
		struct termios
        {
            unsigned int c_iflag;		/* input mode flags */
            unsigned int c_oflag;		/* output mode flags */
            unsigned int c_cflag;		/* control mode flags */
            unsigned int c_lflag;		/* local mode flags */
            unsigned char c_line;			/* line discipline */
            unsigned char c_cc[32];		/* control characters */
            unsigned int c_ispeed;		/* input speed */
            unsigned int c_ospeed;		/* output speed */
		};

		int tcgetattr(int __fd, struct termios *__termios_p);
        int tcsetattr(int __fd, int __optional_actions, const struct termios *__termios_p); 
        
        int usleep(uint32_t);
    ]])
    
	local ISIG = 0000001
	local ICANON = 0000002
	local ECHO = 0000010
	local VMIN = 6
	local VTIME = 5
	local TCSANOW = 0
	local stdin = 0

    local old_attributes
    
    start = function()
        if not old_attributes then
            old_attributes = ffi.new("struct termios[1]")
            ffi.C.tcgetattr(stdin, old_attributes)
        end
        local attr = ffi.new("struct termios[1]")

        ffi.C.tcgetattr(stdin, attr)

        attr[0].c_lflag = bit.band(attr[0].c_lflag, bit.bnot(bit.bor(ICANON, ECHO, ISIG)))
        attr[0].c_cc[VMIN] = 0
        attr[0].c_cc[VTIME] = 0
        
        ffi.C.tcsetattr(stdin, TCSANOW, attr)
    end
    
    read = function()
        return io.read()
    end

    stop = function()
        ffi.C.tcsetattr(stdin, TCSANOW, old_attributes)
        old_attributes = nil
    end
end

if jit.os == "Windows" then
	ffi.cdef([[		
		struct COORD {
		  short X;
		  short Y;
		};

		struct KEY_EVENT_RECORD {
		  int  bKeyDown;
		  unsigned short  wRepeatCount;
		  unsigned short  wVirtualKeyCode;
		  unsigned short  wVirtualScanCode;
		  union {
			wchar_t UnicodeChar;
			char  AsciiChar;
		  } uChar;
		  unsigned long dwControlKeyState;
		};
		
		struct MOUSE_EVENT_RECORD {
		  struct COORD dwMousePosition;
		  unsigned long dwButtonState;
		  unsigned long dwControlKeyState;
		  unsigned long dwEventFlags;
		};

		struct WINDOW_BUFFER_SIZE_RECORD {
		  struct COORD dwSize;
		};

		struct MENU_EVENT_RECORD {
		  unsigned int dwCommandId;
		};

		struct FOCUS_EVENT_RECORD {
		  int bSetFocus;
		};

		struct INPUT_RECORD {
		  unsigned short  EventType;
		  union {
			struct KEY_EVENT_RECORD KeyEvent;
			struct MOUSE_EVENT_RECORD MouseEvent;
			struct WINDOW_BUFFER_SIZE_RECORD WindowBufferSizeEvent;
			struct MENU_EVENT_RECORD MenuEvent;
			struct FOCUS_EVENT_RECORD FocusEvent;
		  } Event;
		};

	
		int PeekConsoleInputA(
			void* hConsoleInput,
			struct INPUT_RECORD* lpBuffer,
			unsigned long nLength,
			unsigned long * lpNumberOfEventsRead
		);
		
		int ReadConsoleInputA(
			void* hConsoleInput,
			struct INPUT_RECORD* lpBuffer,
			unsigned long nLength,
			unsigned long * lpNumberOfEventsRead
		);
		
        void* GetStdHandle(unsigned long nStdHandle);
        
        int PeekNamedPipe(
            void*  hNamedPipe,
            void*  lpBuffer,
            unsigned long   nBufferSize,
            unsigned long* lpBytesRead,
            unsigned long* lpTotalBytesAvail,
            unsigned long* lpBytesLeftThisMessage
        );
	]])
	
	local  STD_INPUT_HANDLE = -10
	
    local stdin = ffi.C.GetStdHandle(STD_INPUT_HANDLE)
    
    if true then
        read = function()
            local size = ffi.new("unsigned long[1]")
            ffi.C.PeekNamedPipe(stdin, nil,nil,nil, size, nil)
            if size[0] > 0 then
                return io.read()
            end
        end
    else
        local rec = ffi.new("struct INPUT_RECORD[1]")
        local events = ffi.new("unsigned long[1]")
        
        read = function()
            ffi.C.PeekConsoleInputA(stdin, rec, ffi.sizeof(rec), events)
            if events[0] > 0 then
                for i = 1, tonumber(events[0]) do
                    ffi.C.ReadConsoleInputA(stdin, rec, ffi.sizeof(rec), events)
                    local info = rec[0]
                    if info.EventType == 1 and info.Event.KeyEvent.bKeyDown then
                        return string.char(info.Event.KeyEvent.uChar.UnicodeChar), info.Event.KeyEvent
                    end
                end
            end
        end
    end
    start = function() end
    stop = function() end
end

local time = os.clock() + math.random() + 1

local buffer = ""
local pos = 0

start()

local function get_caret_pos()
    io.write("\x1b[6n")

    while true do
        local str = read()
        if str and str:sub(1, 2) == "\27[" then
            y,x = str:match("\27%[(%d+);(%d+)R")
            break
        end
    end

    return tonumber(x), tonumber(y)
end

local function set_caret_pos(x, y)
    io.write("\27[",y,";",x,"f")
end

local function move_caret(ox, oy)
    local x,y = get_caret_pos()
    set_caret_pos(x + ox, y + oy)
end

local function push_caret()
    io.write("\27[s")
end

local function pop_caret()
    io.write("\27[u")
end

local function get_size()
    push_caret()
    set_caret_pos(99999999,99999999)
    local w,h = get_caret_pos()
    pop_caret()
    return w,h
end

local function write_string(x, y, str)
    io.write("\27[s ", "\27[", y, ";", x, "H", "\27[K", str, "\27[u")
end

local function erase_line(y)
    push_caret()
    set_caret_pos(0, y)
    io.write("\27[K")
    pop_caret()
end

local function set_fg_color(r,g,b)
    r = math.floor(r * 255)
    g = math.floor(g * 255)
    b = math.floor(b * 255)
    io.write("\27[38;2;", r, ";", g, ";", b, "m")
end

local function set_bg_color(r,g,b)
    r = math.floor(r * 255)
    g = math.floor(g * 255)
    b = math.floor(b * 255)
    io.write("\27[48;2;", r, ";", g, ";", b, "m")
end

local function find_next_word(buffer, x, dir)
    local left = dir == "left" and buffer:sub(0, x-1):reverse() or buffer:sub(x+1, -1)

    if left:find("^%s", 0) then
        return left:find("%S")
    elseif left:find("^%p", 0) then
        return left:find("%P", 0)
    end
    
    return left:find("%s", 0) or left:find("%p", 0) or #left + 1
end

local x, y = get_caret_pos()

while true do
    ffi.C.usleep(500)

   -- buffer = ("="):rep((math.sin(os.clock() * 10) * 0.5 + 0.5) * 50)

    write_string(0, y, buffer)
    
    local str = read()
    if str then
        local w, h = get_size()
        local x, y = get_caret_pos()

        if str == "" then -- newline/enter?
            erase_line(y)
            set_caret_pos(0, y + 1)
            io.write("> ", buffer, "\n")
            
            local func, err = loadstring(buffer)
            if func then
                local func, res = pcall(func)
                if not func then
                    set_fg_color(1,0,0)
                    io.write(res, "\n")
                    set_fg_color(1,1,1)
                end
            else
                set_fg_color(1,0,0)
                io.write(err, "\n") 
                set_fg_color(1,1,1)
            end

            buffer = ""
            set_caret_pos(0, y + 1)
        elseif str:byte() >= 32 and str:byte() < 127 then -- asci chars
            buffer = buffer:sub(0, x-1) .. str .. buffer:sub(x+#str-1, -1)
            move_caret(#str, 0)
        elseif str:sub(1,2) == "\27[" then
            local seq = str:sub(3, #str)

            if seq == "3~" then -- delete
                buffer = buffer:sub(0, x-1) .. buffer:sub(x+1, -1)
            elseif seq == "D" then -- left
                move_caret(-1, 0)
            elseif seq == "C" then -- right
                move_caret(1, 0)
            elseif seq == "H" then -- home
                set_caret_pos(1, y)
            elseif seq == "F" then -- end
                set_caret_pos(#buffer + 1, y)
            elseif seq == "1;5C" then -- ctrl right
                local offset = find_next_word(buffer, x, "right")
                if offset then
                    move_caret(offset + 1, 0)
                end
            elseif seq == "1;5D" then -- ctrl left
                local offset = find_next_word(buffer, x, "left")
                
                if offset then
                    move_caret(-offset + 1, 0)
                end
            else
                print("ansi escape sequence: " .. seq)
            end
        else
            if #str == 1 then
                local byte = str:byte()
                if byte == 3 then -- ctrl c
                    io.write("\nquit\n")
                    break
                elseif byte == 127 then -- backspace
                    buffer = buffer:sub(0, math.max(x - 1 - 1, 0)) .. buffer:sub(x, -1)
                    move_caret(-1, 0)
                elseif byte == 23 then -- ctrl backspace
                    local offset = find_next_word(buffer, x, "left")
    
                    if offset then
                        buffer = buffer:sub(0, x - offset) .. buffer:sub(x, -1)
                    end
                else
                    print("byte: " .. byte)
                end
            elseif str:byte() < 127 then
                if str == "\27\68" then -- ctrl delete
                    local offset = find_next_word(buffer, x, "right")

                    if offset then
                        buffer = buffer:sub(0, x - 1) .. buffer:sub(x + offset, -1)
                    end
                else
                    print("char sequence: " .. table.concat({str:byte(1, #str)}, ", ") .. " (" .. #str .. ")")
                end
            else -- unicode ?
                --buffer = buffer:sub(0, x-1) .. str .. buffer:sub(x+#str-1, -1)
                --move_caret(#str, 0)
            end
        end

        local x, y = get_caret_pos()
        x = math.min(x, #buffer + 1)
        set_caret_pos(x, y)
    end
    if time < os.clock() then
        time = os.clock() + math.random() + 1
       -- print("some text!")
    end
end

stop()