#!/usr/bin/env python
#-*- coding:utf-8 -*-
import os,time,sys,signal

"""
lightup - thinkpad keyboard light control tool
Author: 吕毅 <lvscar@gmail.com> http://lvscar.info
version: 090715

使用:
  lightup --start  闪烁键盘灯
  lightup --stop   停止闪烁键盘灯

特性:
 多次运行 lightup --start 只会占用一个进程。 适合于第三方软件（邮件提醒）调用
 当电脑没有ThinkLight时,使用键盘Scroll Lock灯进行闪烁提醒

配置:
   0. 如果你电脑没有ThinkLight,或只想使用ScrollLock灯进行闪烁提醒,只需执行步骤3,4中的操作.
   1. 首先把当前用户添加到root用户组    $sudo usermod -aG root `whoami`
   2. 修改键盘灯控制文件权限           $sudo chmod g+w  /proc/acpi/ibm/light
   2.1 开机自动调整键盘灯权限          $sudo su root  #echo -e '#!/bin/bash \nchmod g+w /proc/acpi/ibm/light' > /etc/init.d/thinkpad-light ; ln -s /etc/init.d/thinkpad-light /etc/rc5.d/S90thinkpad-light
   3. 设置lightup为可执行            $chmod +x lightup
   4. 把lightup复制到/usr/local/bin/ $sudo cp lightup /usr/local/bin/
"""

LIGHT_CONTROL_FILE =  "/proc/acpi/ibm/light"
PID_MARK_FILE =  "/tmp/lightup.pid"
BLINK_INTERVAL_SECOND =  1

control_file_obj = None
def getControlFileObj():
    global control_file_obj
    if not control_file_obj:
        control_file_obj = open(LIGHT_CONTROL_FILE,"w")
    return control_file_obj
    

def lightup():
    try:
        control_file_obj = getControlFileObj()
        control_file_obj.seek(0)
        control_file_obj.write("on")
        control_file_obj.flush()
    except:
        xset_result = os.system("xset led on")
        if xset_result != 0:
            print "xset command not available. if you use debian or ubuntu ,run \n$sudo apt-get  x11-xserver-utils\nfor install "


def lightdown():
    try:
        control_file_obj = getControlFileObj()
        control_file_obj.seek(0)
        control_file_obj.write("off")
        control_file_obj.flush()
    except:
        xset_result = os.system("xset led off")
        if xset_result != 0:
            print "xset command not available. if you use debian or ubuntu ,run \n$sudo apt-get  x11-xserver-utils\nfor install "



def blink():
    while True:
        lightup()
        time.sleep(BLINK_INTERVAL_SECOND)
        lightdown()
        time.sleep(BLINK_INTERVAL_SECOND)


def writePidMark():
    current_pid = os.getpid()
    try:
        pid_mark_file = open(PID_MARK_FILE,"w")
        pid_mark_file.write(str(current_pid))
    finally:
        pid_mark_file.close()

def deletePidMark():
    if os.path.isfile(PID_MARK_FILE):
        os.remove(PID_MARK_FILE)

def getPid():
    if os.path.isfile(PID_MARK_FILE):
        try:
            return int(open(PID_MARK_FILE).read())
        except:
            return None
    else:
        return None

def start():
    try:
        writePidMark()
        blink()
    finally:
        lightdown()
        deletePidMark()


def main():
    argv = sys.argv
    if len(argv) != 2  :
        print "Usage:lightup --start|--stop"
        sys.exit(0)
    if argv[1] == "--start":
        current_pid = getPid()
        if current_pid:
            try:
                os.kill(current_pid,signal.SIGTERM)
            finally:
                start()
        else:
            start()

    elif argv[1] == "--stop":
        current_pid = getPid()
        if not current_pid:
            sys.exit(0)
        else:
            try:
                os.kill(current_pid,signal.SIGTERM)
            finally:
                deletePidMark()
                lightdown()
                sys.exit(0)
    else:
        print "Usage:lightup --start|--stop"
    
if __name__ == "__main__":
    main()