#!/usr/bin/env python
# -*- coding: utf-8 -*-

# this file is part of beremiz
#
# copyright (c) 2011-2014: laurent bessard, edouard tisserant
#                          rtes lab : crkim, jblee, youcu
#                          higen motor : donggu kang
#
# see copying file for copyrights details.


import os
import signal
import subprocess
import ctypes
from threading import Thread
import time
import re

import runtime.PLCObject as PLCObject
from runtime.loglevels import LogLevelsDict

SDOAnswered = PLCBinary.SDOAnswered
SDOAnswered.restype = None
SDOAnswered.argtypes = []

SDOThread = None
SDOProc = None
Result = None


def SDOThreadProc(*params):
    global Result, SDOProc
    if params[0] == "upload":
        cmdfmt = "ethercat upload -p %d -t %s 0x%.4x 0x%.2x"
    else:
        cmdfmt = "ethercat download -p %d -t %s 0x%.4x 0x%.2x %s"

    command = cmdfmt % params[1:]
    SDOProc = subprocess.Popen(command, stdout=subprocess.PIPE, shell=True)
    res = SDOProc.wait()
    output = SDOProc.communicate()[0]

    if params[0] == "upload":
        Result = None
        if res == 0:
            if params[2] in ["float", "double"]:
                Result = float(output)
            elif params[2] in ["string", "octet_string", "unicode_string"]:
                Result = output
            else:
                hex_value, dec_value = output.split()
                if int(hex_value, 16) == int(dec_value):
                    Result = int(dec_value)
    else:
        Result = res == 0

    SDOAnswered()
    if res != 0:
        PLCObject.LogMessage(
            LogLevelsDict["WARNING"],
            "%s : %s" % (command, output))


def EthercatSDOUpload(pos, index, subindex, var_type):
    global SDOThread
    SDOThread = Thread(target=SDOThreadProc, args=["upload", pos, var_type, index, subindex])
    SDOThread.start()


def EthercatSDODownload(pos, index, subindex, var_type, value):
    global SDOThread
    SDOThread = Thread(target=SDOThreadProc, args=["download", pos, var_type, index, subindex, value])
    SDOThread.start()


def GetResult():
    return Result


KMSGPollThread = None
StopKMSGThread = False


def KMSGPollThreadProc():
    """
    Logs Kernel messages starting with EtherCAT
    Uses GLibc wrapper to Linux syscall "klogctl"
    Last 4 KB are polled, and lines compared to last
    captured line to detect new lines
    """
    libc = ctypes.CDLL("libc.so.6")
    klog = libc.klogctl
    klog.argtypes = [ctypes.c_int, ctypes.c_char_p, ctypes.c_int]
    klog.restype = ctypes.c_int
    s = ctypes.create_string_buffer(4*1024)
    last = None
    while not StopKMSGThread:
        bytes_to_read = klog(3, s, len(s)-1)
        log = s.value[:bytes_to_read-1]
        if last:
            log = log.rpartition(last)[2]
        if log:
            last = log.rpartition('\n')[2]
            for lvl, msg in re.findall(
                    r'<(\d)>\[\s*\d*\.\d*\]\s*(EtherCAT\s*.*)$',
                    log, re.MULTILINE):
                PLCObject.LogMessage(
                    LogLevelsDict[{
                        "4": "WARNING",
                        "3": "CRITICAL"}.get(lvl, "DEBUG")],
                    msg)
        time.sleep(0.5)


# TODO : rename to match _runtime_{location}_extname_init() format
def _runtime_etherlab_init():
    global KMSGPollThread, StopKMSGThread
    StopKMSGThread = False
    KMSGPollThread = Thread(target=KMSGPollThreadProc)
    KMSGPollThread.start()


# TODO : rename to match _runtime_{location}_extname_cleanup() format
def _runtime_etherlab_cleanup():
    global KMSGPollThread, StopKMSGThread, SDOThread
    try:
        os.kill(SDOProc.pid, signal.SIGTERM)
    except Exception:
        pass
    SDOThread = None
    StopKMSGThread = True
    KMSGPollThread = None