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

# This file is part of Beremiz, a Integrated Development Environment for
# programming IEC 61131-3 automates supporting plcopen standard and CanFestival.
#
# Copyright (C) 2007: Edouard TISSERANT and Laurent BESSARD
# Copyright (C) 2017: Andrey Skvortsov
#
# See COPYING file for copyrights details.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.


import os
import re

import util.paths as paths
from xmlclass import GenerateParserFromXSD

from CodeFileTreeNode import CodeFile
from py_ext.PythonEditor import PythonEditor




class PythonFileCTNMixin(CodeFile):

    CODEFILE_NAME = "PyFile"
    SECTIONS_NAMES = [
        "globals",
        "init",
        "cleanup",
        "start",
        "stop"]
    EditorType = PythonEditor

    def __init__(self):
        CodeFile.__init__(self)

        filepath = self.PythonFileName()

        if os.path.isfile(filepath):
            PythonParser = GenerateParserFromXSD(paths.AbsNeighbourFile(__file__, "py_ext_xsd.xsd"))

            xmlfile = open(filepath, 'r')
            pythonfile_xml = xmlfile.read()
            xmlfile.close()

            pythonfile_xml = pythonfile_xml.replace(
                'xmlns="http://www.w3.org/2001/XMLSchema"',
                'xmlns:xhtml="http://www.w3.org/1999/xhtml"')
            for cre, repl in [
                    (re.compile(r"(?<!<xhtml:p>)(?:<!\[CDATA\[)"), "<xhtml:p><![CDATA["),
                    (re.compile(r"(?:]]>)(?!</xhtml:p>)"), "]]></xhtml:p>")]:
                pythonfile_xml = cre.sub(repl, pythonfile_xml)

            try:
                python_code, error = PythonParser.LoadXMLString(pythonfile_xml)
                if error is None:
                    self.CodeFile.globals.setanyText(python_code.getanyText())
                    os.remove(filepath)
                    self.CreateCodeFileBuffer(False)
                    self.OnCTNSave()
            except Exception as exc:
                error = str(exc)

            if error is not None:
                self.GetCTRoot().logger.write_error(
                    _("Couldn't import old %s file.") % self.CTNName())

    def CodeFileName(self):
        return os.path.join(self.CTNPath(), "pyfile.xml")

    def PythonFileName(self):
        return os.path.join(self.CTNPath(), "py_ext.xml")

    PreSectionsTexts = {}
    PostSectionsTexts = {}

    def GetSection(self, section):
        return self.PreSectionsTexts.get(section, "") + "\n" + \
               getattr(self.CodeFile, section).getanyText() + "\n" + \
               self.PostSectionsTexts.get(section, "")

    def CTNGlobalInstances(self):
        variables = self.CodeFileVariables(self.CodeFile)
        ret = [(variable.getname(),
                variable.gettype(),
                variable.getinitial())
               for variable in variables]
        location_str = "_".join(map(str, self.GetCurrentLocation()))
        ret.append(("On_"+location_str+"_Change", "python_poll", ""))
        return ret

    @staticmethod
    def GetVarOnChangeContent(var):
        """
        returns given variable onchange field
        function is meant to allow customization 
        """
        return var.getonchange()

    def CTNGenerate_C(self, buildpath, locations):
        # location string for that CTN
        location_str = "_".join(map(str, self.GetCurrentLocation()))
        configname = self.GetCTRoot().GetProjectConfigNames()[0]

        def _onchangecode(var):
            result = []
            for onchangecall in self.GetVarOnChangeContent(var).split(','):
                onchangecall = onchangecall.strip()
                if onchangecall:
                    result.append(onchangecall + "('" + var.getname() + "')")
            return result


        def _onchange(var):
            content = self.GetVarOnChangeContent(var)
            return repr(content) if content else None

        pyextname = self.CTNName()
        varinfos = [{
                "name": variable.getname(),
                "desc": repr(variable.getdesc()),
                "onchangecode": _onchangecode(variable),
                "onchange": _onchange(variable),
                "opts": repr(variable.getopts()),
                "configname": configname.upper(),
                "uppername": variable.getname().upper(),
                "IECtype": self.GetCTRoot().GetBaseType(variable.gettype()),
                "initial": repr(variable.getinitial()),
                "pyextname": pyextname
            } for variable in self.CodeFile.variables.variable]

        onchange_var_count = len([None for varinfo in varinfos if varinfo["onchange"]])

        # python side PLC global variables access stub
        globalstubs = "\n".join([
            """\
_%(name)s_ctype, _%(name)s_unpack, _%(name)s_pack = \\
    TypeTranslator["%(IECtype)s"]
_PySafeGetPLCGlob_%(name)s = PLCBinary.__SafeGetPLCGlob_%(name)s
_PySafeGetPLCGlob_%(name)s.restype = None
_PySafeGetPLCGlob_%(name)s.argtypes = [ctypes.POINTER(_%(name)s_ctype)]
_PySafeSetPLCGlob_%(name)s = PLCBinary.__SafeSetPLCGlob_%(name)s
_PySafeSetPLCGlob_%(name)s.restype = None
_PySafeSetPLCGlob_%(name)s.argtypes = [ctypes.POINTER(_%(name)s_ctype)]
_%(pyextname)sGlobalsDesc.append((
    "%(name)s",
    "%(IECtype)s",
    %(initial)s,
    %(desc)s,
    %(onchange)s,
    %(opts)s))
""" % varinfo + ("""
_PyOnChangeCount_%(name)s = ctypes.c_uint.in_dll(PLCBinary,"__%(name)s_onchange_count")
_PyOnChangeFirst_%(name)s = _%(name)s_ctype.in_dll(PLCBinary,"__%(name)s_onchange_firstval")
_PyOnChangeLast_%(name)s = _%(name)s_ctype.in_dll(PLCBinary,"__%(name)s_onchange_lastval")
""" % varinfo if varinfo["onchange"] else "") for varinfo in varinfos])

        on_change_func_body = "\n".join(["""
    if _PyOnChangeCount_%(name)s.value > 0:
        # %(name)s
        try:""" % varinfo + """
            """ + """
            """.join(varinfo['onchangecode'])+"""
        except Exception as e:
            errors.append("%(name)s: "+str(e))
""" % varinfo for varinfo in varinfos if varinfo["onchange"]])
        # Runtime calls (start, stop, init, and cleanup)
        rtcalls = ""
        for section in self.SECTIONS_NAMES:
            if section != "globals":
                rtcalls += "def _runtime_%s_%s():\n" % (location_str, section)
                sectiontext = self.GetSection(section).strip()
                if sectiontext:
                    rtcalls += '    ' + \
                        sectiontext.replace('\n', '\n    ')+"\n\n"
                else:
                    rtcalls += "    pass\n\n"

        globalsection = self.GetSection("globals")

        loc_dict = {
            "pyextname": pyextname,
            "globalstubs": globalstubs,
            "globalsection": globalsection,
            "rtcalls": rtcalls,
            "location_str": location_str,
            "on_change_func_body":on_change_func_body,
            "onchange_var_count": onchange_var_count
        }

        PyFileContent = """\
#!/usr/bin/env python
# -*- coding: utf-8 -*-
## Code generated by Beremiz python mixin confnode
##

## Code for PLC global variable access
from runtime.typemapping import TypeTranslator
import ctypes

_PySafeGetChanges_%(pyextname)s = PLCBinary.PySafeGetChanges_%(location_str)s
_PySafeGetChanges_%(pyextname)s.restype = None
_PySafeGetChanges_%(pyextname)s.argtypes = None

_%(pyextname)sGlobalsDesc = []
__ext_name__ = "%(pyextname)s"
PLCGlobalsDesc.append(( "%(pyextname)s" , _%(pyextname)sGlobalsDesc ))
%(globalstubs)s

## User code in "global" scope
%(globalsection)s

## Beremiz python runtime calls
%(rtcalls)s

def On_%(pyextname)s_Change():
    _PySafeGetChanges_%(pyextname)s()
    errors = []
%(on_change_func_body)s
    if len(errors)>0 :
        raise Exception("Exception in %(pyextname)s OnChange call:\\\\n" + "\\\\n".join(errors))

del __ext_name__

""" % loc_dict

        # write generated content to python file
        runtimefile_path = os.path.join(buildpath,
                                        "runtime_%s.py" % location_str)
        runtimefile = open(runtimefile_path, 'wb')
        runtimefile.write(PyFileContent.encode('utf-8'))
        runtimefile.close()

        # C code for safe global variables access

        vardecfmt = """\
extern  __IEC_%(IECtype)s_t %(configname)s__%(uppername)s;
IEC_%(IECtype)s __%(name)s_rbuffer = __INIT_%(IECtype)s;
IEC_%(IECtype)s __%(name)s_wbuffer;
long __%(name)s_rlock = 0;
long __%(name)s_wlock = 0;
int __%(name)s_wbuffer_written = 0;
void __SafeGetPLCGlob_%(name)s(IEC_%(IECtype)s *pvalue){
    while(AtomicCompareExchange(&__%(name)s_rlock, 0, 1));
    *pvalue = __%(name)s_rbuffer;
    AtomicCompareExchange((long*)&__%(name)s_rlock, 1, 0);
}
void __SafeSetPLCGlob_%(name)s(IEC_%(IECtype)s *value){
    while(AtomicCompareExchange(&__%(name)s_wlock, 0, 1));
    __%(name)s_wbuffer = *value;
    __%(name)s_wbuffer_written = 1;
    AtomicCompareExchange((long*)&__%(name)s_wlock, 1, 0);
}

"""

        vardeconchangefmt = """\
unsigned int __%(name)s_rbuffer_written = 0;
IEC_%(IECtype)s __%(name)s_rbuffer_firstval;
IEC_%(IECtype)s __%(name)s_rbuffer_lastval;
unsigned int __%(name)s_onchange_count = 0;
IEC_%(IECtype)s __%(name)s_onchange_firstval;
IEC_%(IECtype)s __%(name)s_onchange_lastval;
"""

        varretfmt = """\
    if(!AtomicCompareExchange(&__%(name)s_wlock, 0, 1)){
        if(__%(name)s_wbuffer_written == 1){
            %(configname)s__%(uppername)s.value = __%(name)s_wbuffer;
            __%(name)s_wbuffer_written = 0;
        }
        AtomicCompareExchange((long*)&__%(name)s_wlock, 1, 0);
    }
"""
        varpubfmt = """\
    if(!AtomicCompareExchange(&__%(name)s_rlock, 0, 1)){
        __%(name)s_rbuffer = __GET_VAR(%(configname)s__%(uppername)s);
        AtomicCompareExchange((long*)&__%(name)s_rlock, 1, 0);
    }
"""

        varpubonchangefmt = """\
    if(!AtomicCompareExchange(&__%(name)s_rlock, 0, 1)){
        IEC_%(IECtype)s tmp = __GET_VAR(%(configname)s__%(uppername)s);
        if(NE_%(IECtype)s(1, NULL, __%(name)s_rbuffer, tmp)){
            if(__%(name)s_rbuffer_written == 0);
                __%(name)s_rbuffer_firstval = __%(name)s_rbuffer;
            __%(name)s_rbuffer_lastval = tmp;
            __%(name)s_rbuffer = tmp;
            /* count one more change */
            __%(name)s_rbuffer_written += 1;
            some_change_found = 1;
        }
        AtomicCompareExchange((long*)&__%(name)s_rlock, 1, 0);
    }
"""

        varcollectchangefmt = """\
    while(AtomicCompareExchange(&__%(name)s_rlock, 0, 1));
    __%(name)s_onchange_count = __%(name)s_rbuffer_written;
    __%(name)s_onchange_firstval = __%(name)s_rbuffer_firstval;
    __%(name)s_onchange_lastval = __%(name)s_rbuffer_lastval;
    /* mark variable as unchanged */
    __%(name)s_rbuffer_written = 0;
    AtomicCompareExchange((long*)&__%(name)s_rlock, 1, 0);

"""
        vardec = "\n".join([(vardecfmt + vardeconchangefmt
                             if varinfo["onchange"] else vardecfmt) % varinfo
                            for varinfo in varinfos])
        varret = "\n".join([varretfmt % varinfo for varinfo in varinfos])
        varpub = "\n".join([(varpubonchangefmt if varinfo["onchange"] else
                             varpubfmt) % varinfo
                            for varinfo in varinfos])
        varcollectchange = "\n".join([varcollectchangefmt % varinfo
                             for varinfo in varinfos if varinfo["onchange"]])

        pysafe_pypoll_code = "On_"+pyextname+"_Change()"

        loc_dict = {
            "vardec": vardec,
            "varret": varret,
            "varpub": varpub,
            "location_str": location_str,
            "pysafe_pypoll_code": '"'+pysafe_pypoll_code+'"',
            "pysafe_pypoll_code_len": len(pysafe_pypoll_code),
            "varcollectchange": varcollectchange,
            "onchange_var_count": onchange_var_count
        }

        # TODO : use config name obtained from model instead of default
        # "config.h". User cannot change config name, but project imported
        # or created in older beremiz vesion could use different name.
        PyCFileContent = """\
/*
 * Code generated by Beremiz py_ext confnode
 * for safe global variables access
 */
#include "iec_types_all.h"
#include "POUS.h"
#include "config.h"
#include "beremiz.h"

PYTHON_POLL* __%(location_str)s_notifier;

/* User variables reference */
%(vardec)s

/* Beremiz confnode functions */
int __init_%(location_str)s(int argc,char **argv){
    __%(location_str)s_notifier = __GET_GLOBAL_ON_%(location_str)s_CHANGE();
    __SET_VAR(__%(location_str)s_notifier->,TRIG,,__BOOL_LITERAL(TRUE));
    __SET_VAR(__%(location_str)s_notifier->,CODE,,__STRING_LITERAL(%(pysafe_pypoll_code_len)d,%(pysafe_pypoll_code)s));

    return 0;
}

void __cleanup_%(location_str)s(void){
}

void __retrieve_%(location_str)s(void){
%(varret)s
}

static int passing_changes_to_python = 0;
void __publish_%(location_str)s(void){
    int some_change_found = 0;
%(varpub)s
    passing_changes_to_python |= some_change_found;
    // call python part if there was at least a change
    if(passing_changes_to_python){
        PYTHON_POLL_body__(__%(location_str)s_notifier);
        passing_changes_to_python &= !(__GET_VAR(__%(location_str)s_notifier->ACK,));
    }
}

void* PySafeGetChanges_%(location_str)s(void){
%(varcollectchange)s
}

""" % loc_dict

        Gen_PyCfile_path = os.path.join(buildpath, "PyCFile_%s.c" % location_str)
        pycfile = open(Gen_PyCfile_path, 'w')
        pycfile.write(PyCFileContent)
        pycfile.close()

        matiec_CFLAGS = '"-I%s"' % os.path.abspath(
            self.GetCTRoot().GetIECLibPath())

        return ([(Gen_PyCfile_path, matiec_CFLAGS)],
                "",
                True,
                ("runtime_%s.py" % location_str, open(runtimefile_path, "rb")))