import os
import math
import tempfile
from io import StringIO
import sys

# --- update the path of Python in case to test this file alone
py_path = os.sys.path
py_pwd = os.path.normpath(os.getcwd() + "/../../../..")
if (py_pwd not in py_path):
    (os.sys.path).append(py_pwd)

# --- import PyROS celestial mechanics from the pyros root directory
import src.core.celme as celme


'''
logger = None

def log_d(msg:str, *args, **kwargs): logger.debug(msg, *args, **kwargs)
def log_i(msg:str, *args, **kwargs): logger.info(msg, *args, **kwargs)
def log_w(msg:str, *args, **kwargs): logger.warning(msg, *args, **kwargs)
def log_e(msg:str, *args, **kwargs): logger.error(msg, *args, **kwargs)
def log_c(msg:str, *args, **kwargs): logger.critical(msg, *args, **kwargs)
'''

class LogPyros:
    """
    Manage PyROS logs in display, file and database.

    First, create an instance:
    log = LogPyros("test",None)

    Second, use the print methods to log:
    log.print("Something to log")
    """

    # CLASS attributes

    _CHRONO_FILENAME = "pyros"
    _CHRONO_FILENAME_WARN = "pyros_warn"

    _GLOBAL_PATH_DATA = ''

    # === Level of log
    '''
    LOG_LEVEL_INFO = 0
    LOG_LEVEL_WARNING = -1
    LOG_LEVEL_ERROR = -2
    LOG_LEVEL_DEBUG = 1
    LOG_LEVEL_DEBUG2 = 2
    '''
    # Python standard logging module values: NOTSET=0, DEBUG=10, INFO=20, WARN=30, ERROR=40, CRITICAL=50
    LOG_LEVEL_NOTSET = 0
    LOG_LEVEL_DEBUG = 10
    LOG_LEVEL_DEBUG2 = 15
    LOG_LEVEL_INFO = 20
    LOG_LEVEL_WARNING = 30
    LOG_LEVEL_ERROR = 40
    LOG_LEVEL_CRITICAL = 50

    # Default LOG level is NOTSET (no filter)
    _GLOBAL_LOG_LEVEL = LOG_LEVEL_NOTSET

    # Start Log_level (threshold) for logging in file
    _FILE_LOG_LEVEL = LOG_LEVEL_DEBUG

    # === Constants
    NO_ERROR = 0

    ERR_ALIAS_NAME_NOT_DEFINED = 10
    
    ERR_FILE_NOT_EXISTS = 101
    ERR_PATH_NOT_EXISTS = 102
    ERR_EMPTY_FILENAME = 103
    ERR_EMPTY_PATHNAME = 104

    # === Private variables
    _last_errno = NO_ERROR

    ##_path_data = ''
    _caller_alias = ''
    _path_data_log  = ''
    _path_wwwpyros = ''

    _date = None
    _home = None
    _noon_hour = 12

    _last_lines = {'chrono':[], 'agent':[]}
    #_last_lines = []
    #_last_lines_agent = []

    _nbmax_last_lines = 30

# =====================================================================
# =====================================================================
# Private methods
# =====================================================================
# =====================================================================

    '''
    def _mkdir_path_log(self):
        # ---
        if self._caller_alias == "":
            self._last_errno = self.ERR_EMPTY_FILENAME
        else:
            self._path_www_log = self._path_wwwpyros + "/logs/" + self._caller_alias
            os.mkdir(self._path_www_log)
        # ---
        if self._path_data == "":
            self._last_errno = self.ERR_EMPTY_PATHNAME
        else:
            self._path_data_log = self._path_data + "/logs/" + self._caller_alias
            os.mkdir(self._path_data_log)
    '''

    def _jd2datedigit(self, jd):
        """ Convert a julian day into a string of YYYYMMDD
        """
        datetmp = self._date.date(jd);
        datedigit = (datetmp.digits(0))[0:8]
        return datedigit

    def _date2night(self, date):
        # night is the truncated part of the date of the previous noon 
        self._date.date(date)
        jd = self._date.jd()
        jd0 = math.floor(jd) - self._noon_hour/24
        d = celme.Date(jd0)
        djd = jd-jd0
        # print(f"jd0 = {d.iso()} djd={djd}")
        if djd>=1:
            jd0 += 1
        djd = jd-jd0
        if djd>=1:
            jd0 += 1
        d = celme.Date(jd0)
        night = d.digits(0)[0:8]
        return night

    def _night2dates(self, night):
        """
        jd_noon0 = previous noon
        jd_midnight = midnight instant
        jd_noon1 = next noon
        """
        d = celme.Date(night)
        d_noon0 = d + self._noon_hour/24
        jd_noon0 = d_noon0.jd()
        jd_midnight = jd_noon0 + 0.5
        jd_noon1 = jd_noon0 + 1.0
        return jd_noon0, jd_midnight, jd_noon1
    
    def _convert_args2str(self, *args, **kwargs):
        """
        return a string as the result of a print method
        """
        bak = sys.stdout # on sauvegarde l'ancien stdout
        result = StringIO()
        sys.stdout = result
        print (*args, **kwargs,end='')
        sys.stdout = bak # on restore stdout
        return result.getvalue()

# =====================================================================
# =====================================================================
# Private methods getter/setter
# =====================================================================
# =====================================================================


    def set_global_log_level(self, log_level:int):
        LogPyros._GLOBAL_LOG_LEVEL = log_level
    def get_global_log_level(self):
        return LogPyros._GLOBAL_LOG_LEVEL

    '''
    def _set_debug_level(self, level:str):
        if type(level).__name__=="bool":
            if level==True:
                level = 1
            else:
                level = 0
        self._debug_level = level
    def _get_debug_level(self):
        return self._debug_level
    '''

    def _set_caller_alias(self, caller_alias:str):
        if caller_alias=="":
            self._last_errno = self.ERR_ALIAS_NAME_NOT_DEFINED
            raise Exception(f"Agent alias must not be empty string.")
        self._caller_alias = caller_alias
        return self.NO_ERROR

    def _get_caller_alias(self):
        return self._caller_alias

    def _set_path_data(self, path_data:str):
        if not os.path.exists(path_data):
            self._last_errno = self.ERR_PATH_NOT_EXISTS
            raise Exception(f"Path '{path_data}' for data does not exists. Create it first manually.")
        self._path_data = path_data
        return self.NO_ERROR
    def _get_path_data(self):
        return self._path_data

    def set_global_path_data(self, path_data:str):
        if not os.path.exists(path_data):
            self._last_errno = self.ERR_PATH_NOT_EXISTS
            raise Exception(f"Path '{path_data}' for data does not exists. Create it first manually.")
        LogPyros._GLOBAL_PATH_DATA = path_data
        return self.NO_ERROR
    def get_global_path_data(self):
        return LogPyros._GLOBAL_PATH_DATA
    def get_full_GLOBAL_PATH_DATA(self):
        return LogPyros._GLOBAL_PATH_DATA + os.sep + "logs"

    def _set_path_wwwpyros(self, path_wwwpyros:str):
        if not os.path.exists(path_wwwpyros):
            self._path_wwwpyros = self.ERR_PATH_NOT_EXISTS
            raise Exception(f"Path '{path_wwwpyros}' for wwwpyros does not exists. Create it first manually.")
        self._path_wwwpyros = path_wwwpyros
        return self.NO_ERROR

    def _get_path_wwwpyros(self):
        return self._path_wwwpyros

    def _set_home(self, home:str):
        self._home.home(home)
        longitude = self._home.longitude
        self._noon_hour = (180 - longitude)/15.0
        # - place noon_hour in the range [0 24[
        if self._noon_hour < 0:
            self._noon_hour += 24
        return self.NO_ERROR

    def _get_home(self):
        return self._home.gps
    
    def _set_logtable(self, logtable):
        self._logtable = logtable
        return self.NO_ERROR

    def _get_logtable(self):
        return self._logtable        

    def _set_nbmax_last_lines(self, nbmax_last_lines):
        self._nbmax_last_lines = nbmax_last_lines
        return self.NO_ERROR

    def _get_nbmax_last_lines(self):
        return self._nbmax_last_lines

# =====================================================================
# =====================================================================
# Property methods
# =====================================================================
# =====================================================================

    caller_alias = property(_get_caller_alias, _set_caller_alias)

    ##path_data = property(_get_path_data, _set_path_data)

    path_wwwpyros = property(_get_path_wwwpyros, _set_path_wwwpyros)

    home = property(_get_home, _set_home)

    logtable = property(_get_logtable, _set_logtable)

# =====================================================================
# =====================================================================
# Public Property methods
# =====================================================================
# =====================================================================

    ##debug_level = property(_get_debug_level, _set_debug_level)
    
    nbmax_last_lines = property(_get_nbmax_last_lines, _set_nbmax_last_lines)
        
# =====================================================================
# =====================================================================
# Methods for users
# =====================================================================
# =====================================================================

    def get_level_name(self, log_level:int):
        if log_level == self.LOG_LEVEL_DEBUG: return "DEBUG"
        if log_level == self.LOG_LEVEL_INFO: return "INFO"
        if log_level == self.LOG_LEVEL_WARNING: return "WARN"
        if log_level == self.LOG_LEVEL_ERROR: return "ERROR"
        if log_level == self.LOG_LEVEL_CRITICAL: return "CRITIC"
        raise Exception("Invalid log level number")

    def log_if_level_lower_than(self, log_level:int, *args, **kwargs):

        """
        This is the method to print in the console display and in a log file.
        In the console display, the message is presented as:
            (Agent_name) message
        In the log file the message is presented as:
            Date-ISO message
        """
        # FILTER : log only if global log level is <= log_level
        if self.get_global_log_level() > log_level: return

        msg = self._convert_args2str(*args, **kwargs)
        # --- prepare the super_msg

        formatted_msg = f"({self._caller_alias}) ({self.get_level_name(log_level)}) {msg}" if msg else ""

        # --- classical print
        print(formatted_msg)
        # --- no more if the agent name is not defined
        if not self._caller_alias: return
        # ---
        # LOG into a file if Agent or if level is enough
        ##self.file(msg)
        ##if self._caller_alias.startswith('Agent') or log_level >= self.LOG_LEVEL_WARNING:

        ##if self._caller_alias.startswith('Agent') or log_level >= self.LOG_LEVEL_INFO:

        #if self._caller_alias.startswith('Agent') or log_level >= self.LOG_LEVEL_DEBUG:
        if self._caller_alias.startswith('Agent') or log_level >= self._FILE_LOG_LEVEL:

            self.file(log_level, msg)

        if log_level >= self.LOG_LEVEL_WARNING:

            self.filewarn(log_level, msg)

        if log_level >= self.LOG_LEVEL_ERROR:
            self.sendmail_error(msg)

    ##if self._debug_level > 0:
    def printd(self, *args, **kwargs): self.log_d(*args, **kwargs)
    def log_d(self, *args, **kwargs): self.log_if_level_lower_than(self.LOG_LEVEL_DEBUG, *args, **kwargs)
    def log_i(self, *args, **kwargs): self.log_if_level_lower_than(self.LOG_LEVEL_INFO, *args, **kwargs)
    def log_w(self, *args, **kwargs): self.log_if_level_lower_than(self.LOG_LEVEL_WARNING, *args, **kwargs)
    def log_e(self, *args, **kwargs): self.log_if_level_lower_than(self.LOG_LEVEL_ERROR, *args, **kwargs)
    def log_c(self, *args, **kwargs): self.log_if_level_lower_than(self.LOG_LEVEL_CRITICAL, *args, **kwargs)

    # DEFAULT LOG methods that log at level INFO
    def log(self, *args, **kwargs): self.log_i(*args, **kwargs)
    def print(self, *args, **kwargs): self.log(*args, **kwargs)



    def log_msg_to_file(self, log_msg, path, file_name, night):

        # 1) Create path if not exists
        if not os.path.exists(path):
            try:
                os.makedirs(path)
            except:
                p = f"Cannot create log path {path}"
                raise Exception(p)        

        # 2) APPEND msg to FULL DAY file
        file_prefix = os.path.normpath(path + os.sep + file_name + '_')
        with open(file_prefix+night+'.log', 'a') as fic:
            fic.write(log_msg+"\n")

        # 3) UPDATE (REWRITE) LAST LINES file (truncated to nbmax_last_lines)

        filetype = "chrono" if file_name==self._CHRONO_FILENAME else "agent"
        ll = self._last_lines[filetype]
        #ll = self._last_lines if file_name == self._CHRONO_FILENAME else self._last_lines_agent

        ll.append(log_msg)
        n = len(ll)

        if n > self.nbmax_last_lines:
            ll = ll[n-self.nbmax_last_lines:]
            #print("ll is", len(ll))
            #print("self._last_lines is", len(self._last_lines))

        with open(file_prefix+'last'+'.log','w') as fic:
            for line in ll:
                fic.write(line+"\n")

        '''
        if file_name == self._CHRONO_FILENAME:

            self._last_lines = ll
        else:
            self._last_lines_agent = ll

        '''
        self._last_lines[filetype] = ll

    ##def file(self, *args, **kwargs):

    def file(self, log_level:int, msg:str):

        """
        This is the method to print in a log file.
        In the log file the message is presented as:
            Date-ISO message
        The last file is also appended with the message
        """

        ##msg = self._convert_args2str(*args, **kwargs)

        # --- no more if the agent name is not defined
        if self._caller_alias=="": return

        # --- 1) Compute the current night digital date
        night = self._date2night("now")
        self._date.date("NOW")

        # --- 2) LOG message to the CHRONO daily unique log file name (pyros.log)
        path = os.path.normpath(self.get_full_GLOBAL_PATH_DATA())

        msg_prefix = f"{self._date.iso()} ({self._caller_alias}) ({self.get_level_name(log_level)}) "

        self.log_msg_to_file(msg_prefix + msg, path, self._CHRONO_FILENAME, night)

        # --- 3) (only) If AGENT, DO THE SAME but to the AGENT daily file (in its own folder) 
        if self._caller_alias.startswith("Agent"):
            path += os.sep + self._caller_alias

            msg_prefix = f"{self._date.iso()} ({self.get_level_name(log_level)}) "

            self.log_msg_to_file(msg_prefix + msg, path, self._caller_alias, night)

    def filewarn(self, log_level:int, msg:str):

        path = os.path.normpath(self.get_full_GLOBAL_PATH_DATA())
        log_filename = os.path.normpath(path + os.sep + self._CHRONO_FILENAME_WARN)

        log_msg = f"{self._date.iso()} ({self._caller_alias}) ({self.get_level_name(log_level)}) {msg}"

        with open(log_filename+'.log', 'a') as fic:
            fic.write(log_msg+"\n")

    # TODO:
    def sendmail_error(self, msg:str):
        pass

    def db(self, *args, **kwargs):
        """
        This is the method to print in the agent_log table of the database.
        """
        if self.logtable==None: return
        msg = self._convert_args2str(*args, **kwargs)
        self.logtable.objects.create(name=self._caller_alias, message=msg)
    
# =====================================================================
# =====================================================================
# Special methods
# =====================================================================
# =====================================================================

    def __init__(self, caller_name:str, logtable=None, home:str="GPS 0 E 43 150", path_data:str="", path_wwwpyros:str=""  ):
        self._last_errno = self.NO_ERROR
        # ---
        self.caller_alias = caller_name if caller_name else "Unknown_agent"
        #print("CALLER IS set to ", self.caller_alias)
        # ---
        if path_data:
            ##self.path_data = path_data
            self.set_global_path_data(path_data)
        elif not self.get_global_path_data():
            ##self.path_data = tempfile.gettempdir()
            ##print("log self.path_data is", self.path_data)
            self.set_global_path_data(tempfile.gettempdir())
        print("log self.global_path_data is", self.get_global_path_data())
        # ---
        if path_wwwpyros != "":
            self.path_wwwpyros = path_wwwpyros
        self._date = celme.Date()
        self._home = celme.Home(home)
        self._noon_hour = 12 ; # local hour corresponding to the date change
        self.logtable = None
        self.nbmax_last_lines = 30

# =====================================================================
# =====================================================================
# Test if main
# =====================================================================
# =====================================================================
    
if __name__ == "__main__":
    
    # === Instance parameters
    
    # --- caller_alias = string added at the begining of each line of display log 
    # --- caller_alias = is the name of log files
    # --- caller_alias = is the field name of database logs
    caller_alias = "test"
    # --- caller_alias = directory where are written log files 
    path_data = "c:/srv/work/pyros"
    # --- home = define the hour of noon when log files are archived 
    home = "GPS 2 E 43 148"
    
    # === Instanciation

    # --- The second parameter is the Django object for database   
    log = LogPyros(caller_alias,None,home,path_data)
    
    # === Use of logs. Parameters are the same as a Python print

    a = 2
    b = 'tutu'
    log.print(f"a={a} b={b}")
    
    log.print(a,b)