import hashlib
import subprocess

import netCDF4
import numpy as np
import re
from autosubmit.config.log import Log
from cdo import Cdo
from nco import Nco
import tempfile
import os
import shutil


class Utils(object):
    """
    Container class for miscellaneous utility methods
    """

    nco = Nco()
    """An instance of Nco class ready to be used"""
    cdo = Cdo()
    """An instance of Cdo class ready to be used"""

    @staticmethod
    def setminmax(filename, variable_list):
        """
        Sets the valid_max and valid_min values to the current max and min values on the file
        :param filename: path to file
        :type filename: str
        :param variable_list: list of variables in which valid_min and valid_max will be set
        :type variable_list: str | list
        """
        if isinstance(variable_list, basestring):
            variable_list = variable_list.split()

        Log.info('Getting max and min values for {0}', ' '.join(variable_list))

        handler = Utils.openCdf(filename)
        for variable in variable_list:
            var = handler.variables[variable]
            values = [np.max(var), np.min(var)]
            Utils.nco.ncatted(input=filename, output=filename,
                              options='-h -a valid_max,{0},m,f,{1}'.format(variable, values[0]))
            Utils.nco.ncatted(input=filename, output=filename,
                              options='-h -a valid_min,{0},m,f,{1}'.format(variable, values[1]))
        handler.close()

    @staticmethod
    def rename_variable(filepath, old_name, new_name, must_exist=True, rename_dimension=False):
        """
        Rename multiple variables from a NetCDF file
        :param filepath: path to file
        :type filepath: str
        :param old_name: variable's name to change
        :type old_name: str
        :param new_name: new name
        :type new_name: str
        :param must_exist: if True, the function will raise an exception if the variable name does not exist
        :type must_exist: bool
        :param rename_dimension: if True, also rename dimensions with the same name
        :type rename_dimension: bool
        """
        Utils.rename_variables(filepath, {old_name: new_name}, must_exist, rename_dimension)

    @staticmethod
    def rename_variables(filepath, dic_names, must_exist=True, rename_dimension=False):
        """
        Rename multiple variables from a NetCDF file
        :param filepath: path to file
        :type filepath: str
        :param dic_names: dictionary containing old names as keys and new names as values
        :type dic_names: dict
        :param must_exist: if True, the function will raise an exception if the variable name does not exist
        :type must_exist: bool
        :param rename_dimension: if True, also rename dimensions with the same name
        :type rename_dimension: bool
        """
        handler = Utils.openCdf(filepath)

        for old_name, new_name in dic_names.items():
            if old_name in handler.variables:
                if new_name not in handler.variables:
                    handler.renameVariable(old_name, new_name)
            elif must_exist:
                raise Exception("Variable {0} does not exist in file {1}".format(old_name, filepath))

            if rename_dimension:
                if old_name in handler.dimensions:
                    handler.renameDimension(old_name, new_name)
                elif must_exist:
                    raise Exception("Dimension {0} does not exist in file {1}".format(old_name, filepath))
            handler.sync()

        handler.close()

    @staticmethod
    def move_file(source, destiny):
        """
        Moves a file from source to destiny, creating dirs if necessary

        :param source: path to source
        :type source: str
        :param destiny:  path to destiny
        :type destiny: str
        """
        if not os.path.exists(os.path.dirname(destiny)):
            try:
                os.makedirs(os.path.dirname(destiny))
            except OSError as ex:
                # This can be due to a race condition. If directory already exists, we don have to do nothing
                if not os.path.exists(os.path.dirname(destiny)):
                    raise ex
        hash_destiny = None
        hash_original = Utils.get_file_hash(source)

        retrials = 5
        while hash_original != hash_destiny:
            if retrials == 0:
                raise Exception('Can not move {0} to {1}'.format(source, destiny))
            shutil.copy(source, destiny)
            hash_destiny = Utils.get_file_hash(destiny)
        os.remove(source)

    @staticmethod
    def get_file_hash(filepath):
        """
        Returns the MD5 hash for the given filepath
        :param filepath: path to the file to compute hash on
        :type filepath:str
        :return: file's MD5 hash
        :rtype: str
        """
        BLOCKSIZE = 65536
        hasher = hashlib.md5()
        with open(filepath, 'rb') as afile:
            buf = afile.read(BLOCKSIZE)
            while len(buf) > 0:
                hasher.update(buf)
                buf = afile.read(BLOCKSIZE)
        return hasher.hexdigest()

    @staticmethod
    def execute_shell_command(command, log_level=Log.DEBUG):
        """
        Executes a sheel command
        :param command: command to execute
        :type command: str|list
        :param log_level: log level to use for command output
        :type log_level: int
        :return: command output
        :rtype: list
        """
        if isinstance(command, basestring):
            command = command.split()
        process = subprocess.Popen(command, stdout=subprocess.PIPE)
        output = list()
        comunicate = process.communicate()
        if log_level != Log.NO_LOG:
            for line in comunicate:
                if not line:
                    continue
                Log.log.log(log_level, line)
                output.append(line)
        if process.returncode != 0:
            raise Exception('Error executing {0}\n Return code: {1}', ' '.join(command), process.returncode)
        return output

    _cpu_count = None

    @staticmethod
    def available_cpu_count():
        """ Number of available virtual or physical CPUs on this system, i.e.
        user/real as output by time(1) when called with an optimally scaling
        userspace-only program"""
        if Utils._cpu_count is None:
            try:
                m = re.search(r'(?m)^Cpus_allowed:\s*(.*)$',
                              open('/proc/self/status').read())
                if m:
                    res = bin(int(m.group(1).replace(',', ''), 16)).count('1')
                    if res > 0:
                        Utils._cpu_count = res
            except IOError:
                try:
                    import multiprocessing
                    Utils._cpu_count = multiprocessing.cpu_count()
                    return Utils._cpu_count
                except (ImportError, NotImplementedError):
                    Utils._cpu_count = -1
        Log.info('Available cores: {0}', Utils._cpu_count)
        return Utils._cpu_count

    @staticmethod
    def convert2netcdf4(filetoconvert):
        temp = TempFile.get()
        handler = Utils.openCdf(filetoconvert)
        if handler.file_format == 'NETCDF4':
            handler.close()
            return
        handler.close()
        Log.debug('Reformatting to netCDF-4')
        Utils.execute_shell_command(["nccopy", "-4", "-d4", "-s", filetoconvert, temp])
        shutil.move(temp, filetoconvert)

    # noinspection PyPep8Naming
    @staticmethod
    def openCdf(filepath, mode='a'):
        return netCDF4.Dataset(filepath, mode)

    @staticmethod
    def get_datetime_from_netcdf(handler, time_variable='time'):
        nctime = handler.variables[time_variable][:]  # get values
        units = handler.variables[time_variable].units  # get unit  "days since 1950-01-01T00:00:00Z"

        try:
            cal_temps = handler.variables[time_variable].calendar
        except AttributeError:  # Attribute doesn't exist
            cal_temps = u"gregorian"  # or standard
        return netCDF4.num2date(nctime, units=units, calendar=cal_temps)

    @staticmethod
    def copy_variable(source, destiny, variable, must_exist=True):
        if not must_exist and variable not in source.variables.keys():
            return
        if variable in destiny.variables.keys():
            return
        original_var = source.variables[variable]
        new_var = destiny.createVariable(variable, original_var.datatype, original_var.dimensions)
        new_var.setncatts({k: original_var.getncattr(k) for k in original_var.ncattrs()})
        new_var[:] = original_var[:]


class TempFile(object):
    """
    Class to manage temporal files
    """

    autoclean = True
    """
    If True, new temporary files are added to the list for future cleaning
    """
    files = list()
    """
    List of files to clean automatically
    """
    scratch_folder = ''
    """
    Scratch folder to create temporary files on it
    """
    prefix = 'temp'
    """
    Prefix for temporary filenames
    """

    @staticmethod
    def get(filename=None, clean=None, suffix='.nc'):
        """
        Gets a new temporal filename, storing it for automated cleaning

        :param suffix:
        :param filename: if it is not none, the function will use this filename instead of a random one
        :type filename: str
        :param clean: if true, stores filename for cleaning
        :type clean: bool
        :return: path to the temporal file
        :rtype: str
        """
        if clean is None:
            clean = TempFile.autoclean

        if filename:
            path = os.path.join(TempFile.scratch_folder, filename)
        else:

            fd, path = tempfile.mkstemp(dir=TempFile.scratch_folder, prefix=TempFile.prefix, suffix=suffix)
            os.close(fd)

        if clean:
            TempFile.files.append(path)

        return path

    @staticmethod
    def clean():
        """
        Removes all temporary files created with Tempfile until now
        """
        for temp_file in TempFile.files:
            if os.path.exists(temp_file):
                os.remove(temp_file)
        TempFile.files = list()


def main():
    print Utils.move_file('/esnas/exp/ecearth/a04e/original_files/19930501/fc0/outputs/ICMGGa04e+199305.grb',
                          '/scratch/Earth/jvegas/temp.nc')

if __name__ == "__main__":
    main()