# python c:\srv\develop\pyros\config\configpyros.py
# ----------------------------------------------------------------------------------------------------
# Parameter attributes = section, key, value, type, unit, access, comment, label, reference, timestamp
# ----------------------------------------------------------------------------------------------------
"""
Example of 
config = ConfigPyros()
config.set_configfile('/tmp/myconfig.xml')
stmod = config.get_paramvalue('angentX','general','startmode')
"""
# ----------------------------------------------------------------------------------------------------

from lxml import etree
import os
import socket
import random

class ConfigPyros:
    
    # === Constants
    NO_ERROR = 0

    ERR_FILE_NOT_EXISTS = 101
    ERR_XML_FILE_ERROR  = 102

    ERR_A_SUBTAG_UNIT_HAVE_NO_ATTRIBUTE_ALIAS = 301
    ERR_ASSEMBLED_ALIAS_NOT_DEFINED        = 302
    ERR_NO_MOUNT_ASSEMBLED                 = 303
    ERR_ONLY_ONE_MOUNT_CAN_BE_ASSEMBLED    = 304
    ERR_NO_CHANNEL_ASSEMBLED               = 305
    ERR_NO_DATABASE_ASSEMBLED              = 306

    # === Private variables
    _last_errno = NO_ERROR
    _last_errparam1 = ""
    # --- XML file
    _config_filename = ""
    _config_filename_mtime = 0
    _config_filename_need_to_be_read = True
    # --- XML structure
    _tags_to_scan = None
    # --- XML contents
    _config_contents_valid = False
    _config_contents_changed = False
    _tree = None
    _root = None
    _unit_subtags = None
    _tag_aliases = None
    _assemblies = None
    # --- Computer infos
    _hostname = None
    _this_computer_alias = None
    
# =====================================================================
# =====================================================================
# Private methods
# =====================================================================
# =====================================================================
                
    def _configfile_verify(self):
        """ Update parameters of the configuration file (existing, modification date)
        """
        self._config_filename_need_to_be_read = False
        self._last_errno = self.NO_ERROR
        if os.path.isfile(self._config_filename):
            # --- verify the date of last modification of the file
            config_filename_mtime = os.path.getmtime(self._config_filename)
            if config_filename_mtime > self._config_filename_mtime:
                self._config_filename_need_to_be_read = True                
                #### self._config_filename_mtime = config_filename_mtime
        else:
            self._last_errno = self.ERR_FILE_NOT_EXISTS
    
    def _parse_xml2lists(self, verbose:bool = False):
        """ Transform the DOM XML structure into usable lists for PyROS
        """
        
        if (verbose==True):
            print("============== Subtags of <unit> Information with attribute alias")
            
        unit_subtags = []
        tags_to_scan = ['']
        xpath = '/unit' + '/*'
        for elem in self._root.xpath(xpath):
            if str(type(elem)) != "<class 'lxml.etree._Element'>":
                continue
            if elem.tag in unit_subtags:
                continue
            if elem.attrib.get('alias',None) == None:
                continue
            unit_subtags.append(elem.tag)
            tags_to_scan.append(elem.tag)
        if (verbose==True):
            print("<{}> subtags = {}".format(xpath, unit_subtags))

        # --- verify the presence of at less one of the following subtag of <unit>
        mandatory_tags = ['', 'database', 'mount', 'channel', 'computer', 'agent']
        for mandatory_tag in mandatory_tags:
            if mandatory_tag not in tags_to_scan:
                self._last_errno = self.ERR_A_SUBTAG_UNIT_HAVE_NO_ATTRIBUTE_ALIAS
                if mandatory_tag == '':
                    self._last_errparam1 = 'unit'
                else:
                    self._last_errparam1 = mandatory_tag
                return False                

        # --- Get all aliases of subtags of <unit>
        # --- Set the tag_aliases dictionnary of lists
        tag_aliases = {}
        for tag in tags_to_scan:
                            
            if tag == "":
                xpath = '/unit'
                tag = 'unit'
            else:
                xpath = '/unit/' + tag
            if (verbose==True):
                print("============== Aliases of <" + tag + ">")
                
            attrib_key_to_get = 'alias'
            aliases = self.get_attribute_level0(xpath,attrib_key_to_get)
            if (verbose==True):
                print("<{} {}> = {}".format(xpath, attrib_key_to_get, aliases))
            if aliases == [None]:
                self._last_errno = self.ERR_TAG_MOUNT_HAVE_NO_ATTRIBUTE_ALIAS
                return False
            tag_aliases[tag] = aliases
        
        if (verbose==True):
            print("============== Unit all alias intantiations in one list")
            
        # --- get all the assemblies
        xpath = '/unit'
        attrib_to_select = {'alias': (tag_aliases['unit'])[0]}
        tag_to_get = "param"
        tag_attrib_to_select = {'section': 'assembly', 'key': 'alias'}
        tag_attrib_key_to_get = 'value'
        assembled_aliases =  self.get_attribute_level1(xpath,attrib_to_select,tag_to_get,tag_attrib_to_select,tag_attrib_key_to_get)
        if (verbose==True):
            print("{} <{} {}> = {}".format(attrib_to_select, tag_to_get, tag_attrib_to_select, assembled_aliases))

        if (verbose==True):
            print("============== Unit alias intantiations in dictionnary of tags")

        # --- Set the assembly dictionnary of lists
        assemblies = {}
        for assembled_alias in assembled_aliases:
            als = []
            for tag in tags_to_scan:
                if tag == '':
                    continue
                #print("tag = {}".format(tag))
                #print("assembled_alias = {}".format(assembled_alias))
                #print("tag_aliases[tag] = {}".format(tag_aliases[tag]))
                if assembled_alias in tag_aliases[tag]:
                    als.append(assembled_alias)
                    the_tag = tag
            #print("n = {}".format(n))
            if len(als) == 0:
                self._last_errno = self.ERR_ASSEMBLED_ALIAS_NOT_DEFINED
                self._last_errparam1 = tag
                return False
            else:
                assemblies[the_tag] = als
        if (verbose==True):
            print("assemblies = {}".format(assemblies))

        # --- check the number of mounts assembled
        if 'mount' in assemblies.keys():
            if (len(assemblies['mount']) > 1):
                if (verbose==True):
                    print("Error: Only one mount can be assembled")
                self._last_errno = self.ERR_ONLY_ONE_MOUNT_CAN_BE_ASSEMBLED
                return False
        else:
            if (verbose==True):
                print("Error: No mount assembled")
            self._last_errno = self.ERR_NO_MOUNT_ASSEMBLED
            return False

        # --- check the number of channels assembled
        if 'channel' not in assemblies.keys():
            if (verbose==True):
                print("Error: No channel assembled")
            self._last_errno = self.ERR_NO_CHANNEL_ASSEMBLED
            return False

        # --- Chack the computer infos
        if (verbose==True):
            print("============== Unit all alias intantiations in one list")
            
        # --- get all the assemblies
        this_computer_alias = None
        hostname = socket.gethostname()
        aliases = tag_aliases['computer']
        xpath = '/unit/computer'
        tag_to_get = "param"
        tag_attrib_to_select = {'section': 'local', 'key': 'hostname'}
        tag_attrib_key_to_get = 'value'
        for alias in aliases:
            attrib_to_select = {'alias': alias}            
            hname =  self.get_attribute_level1(xpath,attrib_to_select,tag_to_get,tag_attrib_to_select,tag_attrib_key_to_get)
            if hname[0] == hostname:
                this_computer_alias = alias
        
        # --- Everything was OK until this point. Validate the XML
        self._unit_subtags = unit_subtags
        self._tags_to_scan = tags_to_scan
        self._tag_aliases = tag_aliases
        self._assemblies = assemblies
        self._this_computer_alias = this_computer_alias
       
        return True

    def _alias2xpath(self, alias, subtag=""):
        #print("alias={}".format(alias))
        tag = self.get_unit_subtag(alias)
        #print("tag={}".format(tag))
        if tag == 'unit':
            xpath = '/unit'
        elif tag == None:
            return None
        else:
            xpath = '/unit/' + tag
            if subtag != "":
                xpath += '/' + subtag
        return xpath

    def _encode(self, texte:str, method:str = 'crypted1', phrase:str = "(Af%"):
        if method == 'crypted1':
            lphrase = len(phrase)
            plus = random.randint(1,9)
            for i in range(plus):
                texte += chr(random.randint(32,255))
            texte += chr(ord(str(plus)))
            texte_hexa_codeds = ""
            for i in range(len(texte)):
                phrase_deci = ord(phrase[i%lphrase])+i
                texte_deci = ord(texte[i])
                #texte_hexa = hex(texte_deci)
                texte_deci_coded = (texte_deci + phrase_deci)%256
                texte_hexa_coded = "{0:#0{1}x}".format(texte_deci_coded,4)
                texte_hexa_codeds += texte_hexa_coded[2:4]
                #print("{} raw={} {} {} coded={} {}".format(i,texte[i],texte_deci,phrase_deci,texte_deci_coded,texte_hexa_coded))
            return texte_hexa_codeds
        else:
            return texte
    
    def _decode(self, crypted:str, method:str = 'crypted1', phrase:str = "(Af%"):
        if method == 'crypted1':
            if crypted == '':
                return ''
            lphrase = len(phrase)
            texte_hexa_codeds = crypted
            texte = ""
            for i in range(int(len(texte_hexa_codeds)/2)):
                phrase_deci = ord(phrase[i%lphrase])+i
                texte_hexa_coded = '0x'+texte_hexa_codeds[2*i:2*i+2]
                texte_deci_coded = int(texte_hexa_coded,16)
                texte_deci = (texte_deci_coded - phrase_deci + 256)%256
                texte += chr(texte_deci)
                #print("{} coded={} raw={} {}".format(i,texte_hexa_coded,texte_deci,chr(texte_deci)))
            plus = int(texte[-1])
            texte = texte[0:-1-plus]
            return texte
        else:
            return crypted
        
# =====================================================================
# =====================================================================
# Methods for experimented users
# =====================================================================
# =====================================================================
        
    def get_attribute_level0(self, xpath:str, attrib_key_to_get:str):
        """ Read a list of values ['d', 'e'] from the following XML structure:
        <a>
            <b "c"="d">
                ...
            </b>
            <b "c"="e">
                ...
            </b>
        </a>
        Select the path:      xpath = '/a/b'
        Select key attribute: attrib_key_to_get = 'c'
        Call the method:
        result = ConfigPyros.get_attribute_level0(xpath,attrib_to_select,tag_to_get,tag_attrib_to_select tag_attrib_key_to_get)
        """
        if self._config_contents_valid == False:
            return ""
        root = self._root
        #
        # 1) get the path of /unit/agent with a given attribute
        # --
        attrib_value_to_gets = []
        for elem in root.xpath(xpath):
            if str(type(elem)) != "<class 'lxml.etree._Element'>":
                continue
            attrib_value_to_gets.append( elem.attrib.get(attrib_key_to_get,None) )
        return attrib_value_to_gets
    
    def get_attribute_level1(self, xpath:str, attrib_to_select:dict, tag_to_get:str, tag_attrib_to_select:dict, tag_attrib_key_to_get:str):
        """ Read a value 'k' from the following XML structure:
        <a>
            <b "c"="d">
                <e "f"="g" "h"="i" "j"="k"/>
            </b>
        </a>
        Select the path:                 xpath = '/a/b'
        Select the attribute dictionary: attrib_to_select = {'c': 'd'}
        Select tag:                      tag_to_get = "e"
        Select tag attribute dictionary: tag_attrib_to_select = {'f': 'g', 'h': 'i'}
        Select key attribute:            tag_attrib_key_to_get = 'j'
        Call the method:
        result = ConfigPyros.get_attribute_level1(xpath,attrib_to_select,tag_to_get,tag_attrib_to_select tag_attrib_key_to_get)
        """
        if self._config_contents_valid == False:
            return ""
        root = self._root
        tree = self._tree
        #
        # 1) get the path of /a/b with a given attribute c="d"
        # --
        #print("============== xpath {}".format(xpath))
        nb = 0
        for elem in root.xpath(xpath):
            if str(type(elem)) != "<class 'lxml.etree._Element'>":
                continue
            nbitems = len(attrib_to_select)
            nb = 0
            for key in attrib_to_select.keys():
                value = attrib_to_select[key]            
                vxml = elem.attrib.get(key,None)
                #print("key={} value={} vxml={}".format(key,value,vxml))
                if value == vxml:
                    nb += 1
            #print("nb={} nbitems={}".format(nb,nbitems))
            if nb == nbitems:
                path = tree.getpath(elem)
                #print("tree.getpath(elem) = {}".format(tree.getpath(elem)))
                if nb==0:
                    nb = 1
                break
        #
        # 2) get the list of params correspondong to the selected 'b'
        attrib_value_to_gets = []
        if nb==0:
            return attrib_value_to_gets            
        #print("---------------")
        for elem in root.xpath(path+"/*"):
            if str(type(elem)) != "<class 'lxml.etree._Element'>":
                continue
            #print("  elem.tag= {}".format(elem.tag))
            if elem.tag == tag_to_get:                
                if tag_attrib_to_select == "" and tag_attrib_key_to_get == "":
                    attrib_value_to_gets.append(elem.attrib)
                    #print("  elem.attrib = {}".format(elem.attrib))
                else:
                    nbitems = len(tag_attrib_to_select)
                    #print("  elem.attrib = {}".format(elem.attrib))
                    nb = 0
                    for key in tag_attrib_to_select.keys():
                        value = tag_attrib_to_select[key]            
                        vxml = elem.attrib.get(key,None)
                        #print("key={} value={} vxml={}".format(key,value,vxml))
                        if value == vxml:
                            nb += 1
                    #print("nb={} nbitems={}".format(nb,nbitems))
                    if nb == nbitems:
                        if tag_attrib_key_to_get == "":
                            attrib_value_to_gets.append( elem.attrib )
                        else:
                            attrib_value_to_gets.append( elem.attrib.get(tag_attrib_key_to_get,None) )
        return attrib_value_to_gets            

# =====================================================================
# =====================================================================
# Methods for users
# =====================================================================
# =====================================================================

    def get_last_errno(self):
        """ Get the last error code
        """
        return self._last_errno

    def get_last_errmsg(self):
        """ Get the last error message
        """
        msg = "Unknown error"
        if self._last_errno == self.NO_ERROR: msg = "No error"
        elif self._last_errno == self.ERR_FILE_NOT_EXISTS: msg = "File does not exists"
        elif self._last_errno == self.ERR_XML_FILE_ERROR: msg = "XML file error"
        elif self._last_errno == self.ERR_A_SUBTAG_UNIT_HAVE_NO_ATTRIBUTE_ALIAS: msg = "Tags <{}> have no attribute alias".format(self._last_errparam1)
        elif self._last_errno == self.ERR_ASSEMBLED_ALIAS_NOT_DEFINED: msg = "Instantiated {} not defined in a <{}>".format(self._last_errparam1,self._last_errparam1)
        elif self._last_errno == self.ERR_NO_MOUNT_ASSEMBLED: msg = "No mount assembled"
        elif self._last_errno == self.ERR_ONLY_ONE_MOUNT_CAN_BE_ASSEMBLED: msg = "Only one mount can be assembled"
        elif self._last_errno == self.ERR_NO_CHANNEL_ASSEMBLED: msg = "No channel assembled"
        elif self._last_errno == self.ERR_NO_DATABASE_ASSEMBLED: msg = "No database assembled"

        return msg

    def set_configfile(self, config_filename:str ):
        """ To set the config file name
        
        :param config_filename: A string that contains the full name of the configuration file.
        :type config_filename: string
        """
        if config_filename == "" or config_filename != self._config_filename:
            self._config_filename = config_filename
            self._config_filename_mtime = 0
            self._config_contents_valid = False
            self._tree = None
            self._root = None
        self._configfile_verify()
        return
        
    def get_configfile(self):
        """ Get the current config file name
        """
        return self._config_filename
    
    def is_config_contents_changed(self):
        response =self._config_contents_changed
        self._config_contents_changed = False
        return response
        
    def load(self, verbose:bool = False, force:bool = False):
        """ To load the config file if necessary
        
        :Example:
            
        ConfigPyros().load()
        """

        # --- Verify the existence and the last modification of the XML file
        self._configfile_verify()
        errno = self.get_last_errno()
        if errno != self.NO_ERROR:
            if (verbose==True):
                print("Load Error = {}".format(errno))            
            return
        if self._config_filename_need_to_be_read == False and force == False:
            self._config_contents_changed = False
            return

        # --- Read the configuration file and parse it
        self._last_errno = self.NO_ERROR
        try:
            # --- Save the current tree and root as '_old'
            self._tree_old = self._tree
            self._root_old = self._root
            
            # --- Parse the XML file into DOM
            tree = etree.parse(self._config_filename)

            # --- Get root from the tree
            root = tree.getroot()

            # --- Set the new tree and root
            self._tree = tree
            self._root = root

            # --- Parse the DOM into usable lists
            self._config_contents_valid = True
            valid = self._parse_xml2lists(verbose)

            # --- Validation step
            if valid == True:
                self._config_filename_mtime = os.path.getmtime(self._config_filename)
                self._config_contents_changed = True
            else:
                # --- Se the current tree and root from '_old'
                self._config_contents_valid = False
                self._tree = self._tree_old
                self._root = self._root_old
            
        except:
            self._last_errno = self.ERR_XML_FILE_ERROR
        return

    def get_unit_subtags(self):
        if self._config_contents_valid == False:
            return ""
        return self._unit_subtags

    def get_aliases(self, unit_subtag):
        if self._config_contents_valid == False:
            return ""
        return self._tag_aliases[unit_subtag]

    def get_unit_subtag(self, alias):
        if self._config_contents_valid == False:
            return ""
        for unit_subtag in self._tag_aliases:
            aliases = self.get_aliases(unit_subtag)
            #print("alias={} in aliases={}".format(alias,aliases))
            if alias in aliases:
                return unit_subtag
        return None
    
    def get_params(self, alias, subtag=""):
        """ Select the tag corresponding to alias
        Return the list of dictionaries of all attributes
        """
        if self._config_contents_valid == False:
            return ""
        # --- search the tag from its alias
        xpath = self._alias2xpath(alias, subtag)
        attrib_to_select = {'alias': alias}
        tag_to_get = "param"
        tag_attrib_to_select = ""
        tag_attrib_key_to_get = ""
        #print("get_params alias={} subtag={} xpath={}".format(alias,subtag,xpath))
        value =  self.get_attribute_level1(xpath,attrib_to_select,tag_to_get,tag_attrib_to_select,tag_attrib_key_to_get)
        #print("{} <{} {}> = {}".format(attrib_to_select, tag_to_get, tag_attrib_to_select, value))
        if (len(value)>0):
            return value
        return None

    def get_param(self, alias, section, key, subtag=""):
        """ Select the tag corresponding to alias, and <param> tag with attributes section=, key=
        Return the dictionary of all attributes
        """
        if self._config_contents_valid == False:
            return ""
        # --- search the tag from its alias
        xpath = self._alias2xpath(alias, subtag)
        attrib_to_select = {'alias': alias}
        tag_to_get = "param"
        tag_attrib_to_select = {'section': section, 'key': key}
        tag_attrib_key_to_get = ""
        #print("get_param alias={} subtag={} xpath={}".format(alias,subtag,xpath))
        value =  self.get_attribute_level1(xpath,attrib_to_select,tag_to_get,tag_attrib_to_select,tag_attrib_key_to_get)
        #print("{} <{} {}> = {}".format(attrib_to_select, tag_to_get, tag_attrib_to_select, value))
        if (len(value)>0):
            return value[0]
        return None

    def get_paramvalue(self, alias, section, key, subtag=""):
        """ Select the tag corresponding to alias, and <param> tag with attributes section=, key=
        Return only the value=
        """
        if self._config_contents_valid == False:
            return ""
        # --- search the tag from its alias
        xpath = self._alias2xpath(alias, subtag)
        attrib_to_select = {'alias': alias}
        tag_to_get = "param"
        tag_attrib_to_select = {'section': section, 'key': key}
        tag_attrib_key_to_get = 'value'
        #print("get_paramvalue alias={} subtag={} xpath={}".format(alias,subtag,xpath))
        value =  self.get_attribute_level1(xpath,attrib_to_select,tag_to_get,tag_attrib_to_select,tag_attrib_key_to_get)
        #print("{} <{} {}> = {}".format(attrib_to_select, tag_to_get, tag_attrib_to_select, value))
        if (len(value)>0):
            return value[0]
        return None

    def get_plan(self, alias):
        """ Select the tag corresponding to alias, and <param> tag with attributes section=, key=
        Return the dictionary of all attributes
        """
        if self._config_contents_valid == False:
            return ""
        # --- search the tag from its alias
        subtag = 'plan'
        xpath = self._alias2xpath(alias, subtag)
        #attrib_to_select = {'alias': 'current'}
        attrib_to_select = {}
        tag_to_get = "param"
        tag_attrib_to_select = ""
        tag_attrib_key_to_get = ""
        #print("get_plan alias={} subtag={} xpath={}".format(alias,subtag,xpath))
        value =  self.get_attribute_level1(xpath,attrib_to_select,tag_to_get,tag_attrib_to_select,tag_attrib_key_to_get)
        #print("{} <{} {}> = {}".format(attrib_to_select, tag_to_get, tag_attrib_to_select, value))
        if (len(value)>0):
            return value
        return None

    def get_computer_alias(self):
        if self._config_contents_valid == False:
            return ""
        return self._this_computer_alias

    def encode(self, text:str, method:str = 'crypted1'):
        return self._encode(text,method)

    def decode(self, crypted:str, method:str = 'crypted1'):
        return self._decode(crypted,method)
        
# =====================================================================
# =====================================================================
# Special methods
# =====================================================================
# =====================================================================
        
    def __init__(self, config_filename:str = ""):
        self._last_errno = self.NO_ERROR
        self._unit_component_params = []
        self.set_configfile(config_filename)
        self._configfile_changed = False

# =====================================================================
# =====================================================================
# Test if main
# =====================================================================
# =====================================================================
    
if __name__ == "__main__":
    cwd = os.getcwd()
    # --- Set the filename of the configuration
    config_filename = cwd + '/config_unit_simulunit1.xml'
    print("config_filename = {}\n".format(config_filename))
    
    # --- Instanciate an object for configuration
    config = ConfigPyros()
    config.set_configfile(config_filename)
    
    if config.get_last_errno() != config.NO_ERROR:
        
        print("Error {}. {}".format(config.get_last_errno(),config.get_last_errmsg()))

    else:     

        # --- Load the configuration file if needed only (i.e. modified)
        config.load(False)

        if config.get_last_errno() != config.NO_ERROR:

            print("Error {}. {}".format(config.get_last_errno(),config.get_last_errmsg()))

        else:            

            # --- Get the home of the mount[0]
            mount_alias = config.get_aliases('mount')[0]
            home = config.get_param(mount_alias,'MountPointing','home')
            print("home= {}\n".format(home))
            
            # --- Get the serial number of the optics of the channel[0]
            channel_alias = config.get_aliases('channel')[0]
            optsn = config.get_paramvalue(channel_alias,'optic','serial_number')
            print("Serial number {}\n".format(optsn))
    
            # --- Get the startmode of the AgentX
            agent_alias = 'AgentX'
            stmod = config.get_paramvalue(agent_alias,'general','startmode')
            print("startmode {}\n".format(stmod))

            # --- Get all the assembly of this unit[0] (mount + channels)
            unit_alias = config.get_aliases('unit')[0]
            params = config.get_params(unit_alias)
            print("params {} = {}\n".format(unit_alias,params))

            # --- Get the plan parameters for web pages of the channel[0]
            channel_alias = config.get_aliases('channel')[0]
            plans = config.get_plan(channel_alias)
            print("Plan form = {}\n".format(plans))
                        
            # --- Get the alias of this computer
            print("Alias of this computer = {}\n".format(config.get_computer_alias()))
            
            # --- Get the password of the database
            database_alias = config.get_aliases('database')[0]
            paswds = config.get_param(database_alias,'access','pswd')
            if paswds.get('unit',None) == 'crypted1':
                paswd = config.decode(paswds['value'])
            else:
                paswd = paswds['value']
            print("db paswd = {}\n".format(paswd))