# coding: utf-8
import csv
import shutil
import threading
from datetime import datetime

import numpy as np
import os
import re
from bscearth.utils.log import Log

from earthdiagnostics.utils import Utils, TempFile
from earthdiagnostics.variable import VariableManager
from earthdiagnostics.variable_type import VariableType
from earthdiagnostics.modelingrealm import ModelingRealms
from earthdiagnostics.datafile import NetCDFFile as NCfile, StorageStatus, LocalStatus


class DataManager(object):
    """
    Class to manage the data repositories

    :param config:
    :type config: Config
    """
    def __init__(self, config):
        self.config = config
        self.experiment = config.experiment
        self._checked_vars = list()
        self.variable_list = VariableManager()
        self.variable_list.load_variables(self.config.data_convention)
        UnitConversion.load_conversions()
        self.lock = threading.Lock()
        self.requested_files = {}

    def _get_file_from_storage(self, filepath):
        if filepath not in self.requested_files:
            self.requested_files[filepath] = NCfile.from_storage(filepath)
        file_object = self.requested_files[filepath]
        file_object.local_satatus = LocalStatus.PENDING
        return self.requested_files[filepath]

    def _declare_generated_file(self, remote_file, domain, final_var, cmor_var, data_convention,
                                region, diagnostic, grid, var_type, original_var):
        if remote_file not in self.requested_files:
            self.requested_files[remote_file] = NCfile.to_storage(remote_file)
        file_object = self.requested_files[remote_file]
        file_object.diagnostic = diagnostic
        file_object.var_type = var_type
        file_object.grid = grid
        file_object.data_manager = self
        file_object.domain = domain
        file_object.var = original_var
        file_object.final_name = final_var
        file_object.cmor_var = cmor_var
        file_object.region = region
        file_object.data_convention = data_convention
        file_object.storage_status = StorageStatus.PENDING
        return file_object

    @staticmethod
    def _get_final_var_name(box, var):
        if box:
            var += box.get_lon_str() + box.get_lat_str() + box.get_depth_str()
        return var

    def get_varfolder(self, domain, var, grid=None):
        if grid:
            var = '{0}-{1}'.format(var, grid)

        if domain in [ModelingRealms.ocean, ModelingRealms.seaIce]:
            return '{0}_f{1}h'.format(var, self.experiment.ocean_timestep)
        else:
            return '{0}_f{1}h'.format(var, self.experiment.atmos_timestep)

    def create_link(self, domain, filepath, frequency, var, grid, move_old, vartype):
        freq_str = frequency.folder_name(vartype)

        if not grid:
            grid = 'original'

        variable_folder = self.get_varfolder(domain, var)
        vargrid_folder = self.get_varfolder(domain, var, grid)

        self.lock.acquire()
        try:
            if grid == 'original':
                link_path = os.path.join(self.config.data_dir, self.experiment.expid, freq_str, variable_folder)
                if os.path.islink(link_path):
                    link_path = os.path.join(self.config.data_dir, self.experiment.expid, freq_str, vargrid_folder)

                Utils.create_folder_tree(link_path)
            else:
                link_path = os.path.join(self.config.data_dir, self.experiment.expid, freq_str, vargrid_folder)
                Utils.create_folder_tree(link_path)
                default_path = os.path.join(self.config.data_dir, self.experiment.expid, freq_str, variable_folder)
                original_path = os.path.join(self.config.data_dir, self.experiment.expid, freq_str,
                                             vargrid_folder.replace('-{0}_f'.format(grid), '-original_f'))

                if os.path.islink(default_path):
                    os.remove(default_path)
                elif os.path.isdir(default_path):
                    shutil.move(default_path, original_path)
                os.symlink(link_path, default_path)

            if move_old and link_path not in self._checked_vars:
                self._checked_vars.append(link_path)
                old_path = os.path.join(self.config.data_dir, self.experiment.expid, freq_str,
                                        'old_{0}_f{1}h'.format(var, self.experiment.atmos_timestep))
                regex = re.compile(var + '_[0-9]{6,8}\.nc')
                for filename in os.listdir(link_path):
                    if regex.match(filename):
                        Utils.create_folder_tree(old_path)
                        Utils.move_file(os.path.join(link_path, filename),
                                        os.path.join(old_path, filename))

            link_path = os.path.join(link_path, os.path.basename(filepath))
            if os.path.lexists(link_path):
                os.remove(link_path)
            if not os.path.exists(filepath):
                raise ValueError('Original file {0} does not exists'.format(filepath))
            if not os.path.isdir(os.path.dirname(link_path)):
                Utils.create_folder_tree(os.path.dirname(link_path))
            relative_path = os.path.relpath(filepath, os.path.dirname(link_path))
            os.symlink(relative_path, link_path)
        except:
            raise
        finally:
            self.lock.release()

    # Overridable methods (not mandatory)
    def link_file(self, domain, var, cmor_var, startdate, member, chunk=None, grid=None,
                  frequency=None, year=None, date_str=None, move_old=False, vartype=VariableType.MEAN):
        """
        Creates the link of a given file from the CMOR repository.

        :param cmor_var:
        :param move_old:
        :param date_str:
        :param year: if frequency is yearly, this parameter is used to give the corresponding year
        :type year: int
        :param domain: CMOR domain
        :type domain: Domain
        :param var: variable name
        :type var: str
        :param startdate: file's startdate
        :type startdate: str
        :param member: file's member
        :type member: int
        :param chunk: file's chunk
        :type chunk: int
        :param grid: file's grid (only needed if it is not the original)
        :type grid: str
        :param frequency: file's frequency (only needed if it is different from the default)
        :type frequency: str
        :param vartype: Variable type (mean, statistic)
        :type vartype: VariableType
        :return: path to the copy created on the scratch folder
        :rtype: str
        """
        pass

    def prepare(self):
        """
        Prepares the data to be used by the diagnostic.
        :return:
        """
        pass


class NetCDFFile(object):
    """
    Class to manage netCDF file and pr

    """
    def __init__(self):
        self.remote_file = None
        self.local_file = None
        self.domain = None
        self.var = None
        self.cmor_var = None
        self.region = None
        self.frequency = None
        self.data_convention = None

    @staticmethod
    def from_storage(filepath):
        file_object = NetCDFFile()
        file_object.remote_file = filepath
        return file_object

    @staticmethod
    def to_storage(domain, var, cmor_var, data_convention, region):
        new_object = NetCDFFile()
        new_object.domain = domain
        new_object.var = var
        new_object.cmor_var = cmor_var
        new_object.region = region
        new_object.frequency = None
        new_object.data_convention = data_convention
        return new_object

    def download(self):
        try:
            if not self.local_file:
                self.local_file = TempFile.get()
            Utils.copy_file(self.remote_file, self.local_file)
            Log.info('File {0} ready!', self.remote_file)
        except Exception as ex:
            os.remove(self.local_file)
            Log.error('File {0} not available: {1}', self.remote_file, ex)

    def send(self):
        Utils.convert2netcdf4(self.local_file)
        self._correct_metadata()
        self._prepare_region()
        self._rename_coordinate_variables()

        Utils.move_file(self.local_file, self.remote_file)

    def _prepare_region(self):
        if not self.region:
            return
        if not os.path.exists(self.remote_file):
            self._add_region_dimension_to_var()
        else:
            self._update_var_with_region_data()
            self._correct_metadata()
        Utils.nco.ncks(input=self.local_file, output=self.local_file, options='-O --fix_rec_dmn region')

    def _update_var_with_region_data(self):
        temp = TempFile.get()
        shutil.copyfile(self.remote_file, temp)
        Utils.nco.ncks(input=temp, output=temp, options='-O --mk_rec_dmn region')
        handler = Utils.openCdf(temp)
        handler_send = Utils.openCdf(self.local_file)
        value = handler_send.variables[self.var][:]
        var_region = handler.variables['region']
        basin_index = np.where(var_region[:] == self.region)
        if len(basin_index[0]) == 0:
            var_region[var_region.shape[0]] = self.region
            basin_index = var_region.shape[0] - 1

        else:
            basin_index = basin_index[0][0]
        handler.variables[self.var][..., basin_index] = value
        handler.close()
        handler_send.close()
        Utils.move_file(temp, self.local_file)

    def _add_region_dimension_to_var(self):
        handler = Utils.openCdf(self.local_file)
        handler.createDimension('region')
        var_region = handler.createVariable('region', str, 'region')
        var_region[0] = self.region
        original_var = handler.variables[self.var]
        new_var = handler.createVariable('new_var', original_var.datatype,
                                         original_var.dimensions + ('region',))
        new_var.setncatts({k: original_var.getncattr(k) for k in original_var.ncattrs()})
        value = original_var[:]
        new_var[..., 0] = value
        handler.close()
        Utils.nco.ncks(input=self.local_file, output=self.local_file, options='-O -x -v {0}'.format(self.var))
        Utils.rename_variable(self.local_file, 'new_var', self.var)

    def _correct_metadata(self):
        if not self.cmor_var:
            return
        handler = Utils.openCdf(self.local_file)
        var_handler = handler.variables[self.var]
        self._fix_variable_name(var_handler)
        handler.modeling_realm = self.cmor_var.domain.name
        table = self.cmor_var.get_table(self.frequency, self.data_convention)
        handler.table_id = 'Table {0} ({1})'.format(table.name, table.date)
        if self.cmor_var.units:
            self._fix_units(var_handler)
        handler.sync()
        self._fix_coordinate_variables_metadata(handler)
        var_type = var_handler.dtype
        handler.close()
        self._fix_values_metadata(var_type)

    def _fix_variable_name(self, var_handler):
        var_handler.standard_name = self.cmor_var.standard_name
        var_handler.long_name = self.cmor_var.long_name
        var_handler.short_name = self.cmor_var.short_name

    def _fix_values_metadata(self, var_type):
        if self.cmor_var.valid_min != '':
            valid_min = '-a valid_min,{0},o,{1},"{2}" '.format(self.var, var_type.char, self.cmor_var.valid_min)
        else:
            valid_min = ''
        if self.cmor_var.valid_max != '':
            valid_max = '-a valid_max,{0},o,{1},"{2}" '.format(self.var, var_type.char, self.cmor_var.valid_max)
        else:
            valid_max = ''
        Utils.nco.ncatted(input=self.local_file, output=self.local_file,
                          options='-O -a _FillValue,{0},o,{1},"1.e20" '
                                  '-a missingValue,{0},o,{1},"1.e20" {2}{3}'.format(self.var, var_type.char,
                                                                                    valid_min, valid_max))

    def _fix_coordinate_variables_metadata(self, handler):
        if 'lev' in handler.variables:
            handler.variables['lev'].short_name = 'lev'
            if self.domain == ModelingRealms.ocean:
                handler.variables['lev'].standard_name = 'depth'
        if 'lon' in handler.variables:
            handler.variables['lon'].short_name = 'lon'
            handler.variables['lon'].standard_name = 'longitude'
        if 'lat' in handler.variables:
            handler.variables['lat'].short_name = 'lat'
            handler.variables['lat'].standard_name = 'latitude'

    EQUIVALENT_UNITS = {'-': '1.0', 'fractional': '1.0', 'psu': 'psu'}

    def _fix_units(self, var_handler):
        if 'units' not in var_handler.ncattrs():
            return
        if var_handler.units.lower() in NetCDFFile.EQUIVALENT_UNITS:
            var_handler.units = NetCDFFile.EQUIVALENT_UNITS[var_handler.units.lower()]
        elif var_handler.units == 'C' or self.cmor_var.units == 'K':
            var_handler.units = 'deg_C'
        if self.cmor_var.units != var_handler.units:
            self._convert_units(var_handler)
        var_handler.units = self.cmor_var.units

    def _convert_units(self, var_handler):
        try:
            Utils.convert_units(var_handler, self.cmor_var.units)
        except ValueError as ex:
            Log.warning('Can not convert {3} from {0} to {1}: {2}', var_handler.units, self.cmor_var.units, ex,
                        self.cmor_var.short_name)
            factor, offset = UnitConversion.get_conversion_factor_offset(var_handler.units,
                                                                         self.cmor_var.units)

            var_handler[:] = var_handler[:] * factor + offset
            if 'valid_min' in var_handler.ncattrs():
                var_handler.valid_min = float(var_handler.valid_min) * factor + offset
            if 'valid_max' in var_handler.ncattrs():
                var_handler.valid_max = float(var_handler.valid_max) * factor + offset

    def _rename_coordinate_variables(self):
        variables = dict()
        variables['x'] = 'i'
        variables['y'] = 'j'
        variables['nav_lat_grid_V'] = 'lat'
        variables['nav_lon_grid_V'] = 'lon'
        variables['nav_lat_grid_U'] = 'lat'
        variables['nav_lon_grid_U'] = 'lon'
        variables['nav_lat_grid_T'] = 'lat'
        variables['nav_lon_grid_T'] = 'lon'
        Utils.rename_variables(self.local_file, variables, False, True)

    def add_diagnostic_history(self, diagnostic):
        from earthdiagnostics.earthdiags import EarthDiags
        history_line = 'Diagnostic {1} calculated with EarthDiagnostics version {0}'.format(EarthDiags.version,
                                                                                            diagnostic)
        self._add_history_line(history_line)

    def add_cmorization_history(self):
        from earthdiagnostics.earthdiags import EarthDiags
        history_line = 'CMORized with Earthdiagnostics version {0}'.format(EarthDiags.version)
        self._add_history_line(history_line)

    def _add_history_line(self, history_line):
        utc_datetime = 'UTC ' + datetime.utcnow().isoformat()
        history_line = '{0}: {1};'.format(utc_datetime, history_line)

        handler = Utils.openCdf(self.local_file)
        try:
            history_line = history_line + handler.history
        except AttributeError:
            history_line = history_line
        handler.history = Utils.convert_to_ASCII_if_possible(history_line)
        handler.close()


class UnitConversion(object):
    """
    Class to manage unit conversions
    """
    _dict_conversions = None

    @classmethod
    def load_conversions(cls):
        """
        Load conversions from the configuration file
        """
        cls._dict_conversions = dict()
        with open(os.path.join(os.path.dirname(os.path.realpath(__file__)), 'conversions.csv'), 'rb') as csvfile:
            reader = csv.reader(csvfile, dialect='excel')
            for line in reader:
                if line[0] == 'original':
                    continue
                cls.add_conversion(UnitConversion(line[0], line[1], line[2], line[3]))

    @classmethod
    def add_conversion(cls, conversion):
        """
        Adds a conversion to the dictionary

        :param conversion: conversion to add
        :type conversion: UnitConversion
        """
        cls._dict_conversions[(conversion.source, conversion.destiny)] = conversion

    def __init__(self, source, destiny, factor, offset):
        self.source = source
        self.destiny = destiny
        self.factor = float(factor)
        self.offset = float(offset)

    @classmethod
    def get_conversion_factor_offset(cls, input_units, output_units):
        """
        Gets the conversion factor and offset for two units . The conversion has to be done in the following way:
        converted = original * factor + offset

        :param input_units: original units
        :type input_units: str
        :param output_units: destiny units
        :type output_units: str
        :return: factor and offset
        :rtype: [float, float]
        """
        units = input_units.split()
        if len(units) == 1:
            scale_unit = 1
            unit = units[0]
        else:
            if '^' in units[0]:
                values = units[0].split('^')
                scale_unit = pow(int(values[0]), int(values[1]))
            else:
                scale_unit = float(units[0])
            unit = units[1]

        units = output_units.split()
        if len(units) == 1:
            scale_new_unit = 1
            new_unit = units[0]
        else:
            if '^' in units[0]:
                values = units[0].split('^')
                scale_new_unit = pow(int(values[0]), int(values[1]))
            else:
                scale_new_unit = float(units[0])
            new_unit = units[1]

        factor, offset = UnitConversion._get_factor(new_unit, unit)
        if factor is None:
            return None, None
        factor = factor * scale_unit / float(scale_new_unit)
        offset /= float(scale_new_unit)

        return factor, offset

    @classmethod
    def _get_factor(cls, new_unit, unit):
        # Add  only the conversions with a factor greater than 1
        if unit == new_unit:
            return 1, 0
        elif (unit, new_unit) in cls._dict_conversions:
            conversion = cls._dict_conversions[(unit, new_unit)]
            return conversion.factor, conversion.offset
        elif (new_unit, unit) in cls._dict_conversions:
            conversion = cls._dict_conversions[(new_unit, unit)]
            return 1 / conversion.factor, -conversion.offset
        else:
            return None, None