#!/usr/bin/env python3
# Copyright 2021 - Barcelona Supercomputing Center
# Author: Rodrigo Martín Posada
# MIT License

import f90nml
import pyoasis
from pyoasis import OASIS  # pylint: disable=no-name-in-module
import numpy as np
import logging

NAMELIST_FILE_NAME = 'namelist.amip'
L080_NX = 35718  # number of LAND grid cells at T159 resolution
L128_NX = 88838  # number of LAND grid cells at T255 resolution
L256_NX = 348528  # number of LAND grid cells at T511 resolution
CO2_MODE = False


def def_local_partition(nx, npes, mype):
    il_size = nx // npes
    il_offset = mype * il_size
    if (npes-mype) <= nx % npes:
        il_size += 1
        il_offset += (nx % npes) - (npes-mype)
    return il_size, il_offset


if __name__ == '__main__':
    # Constants from namelist
    nml = f90nml.read(NAMELIST_FILE_NAME)
    COUPLING_INTERVAL = nml['NAMAMIP']['TimeStepSec']
    RUN_LENGTH_SEC = nml['NAMAMIP']['RunLengthSec']

    # Init OASIS
    comp = pyoasis.Component("IFS_MOCK")
    local_comm = comp.localcomm
    # Get rank in local communicator
    mype = comp.localcomm.rank
    npes = comp.localcomm.size

    # Unit for output messages
    out_ifs = 'IFS_mock.out_'+str(100+mype)
    logging.basicConfig(filename=out_ifs, format='%(message)s', level=logging.DEBUG)
    logging.debug('-----------------------------------------------------------')
    logging.debug('I am IFS-mock process with rank : {}'.format(mype))
    logging.debug('in my local communicator gathering {} processes'.format(npes))
    logging.debug('----------------------------------------------------------')

    # +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    #  PARTITION DEFINITION
    # +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    with open('namcouple', 'r') as f:
        contents = f.read()
        if 'AMIP_emissions' in contents:
            CO2_MODE = True
        if 'L080' in contents:
            nx = L080_NX
        elif 'L128' in contents:
            nx = L128_NX
        elif 'L256' in contents:
            nx = L256_NX
        else:
            raise Exception('Invalid IFS grid in namcouple')
    # Definition of the local partition
    il_size, il_offset = def_local_partition(nx, npes, mype)
    logging.debug('Local partition definition')
    logging.debug('il_size, il_offset = {} {}'.format(il_size, il_offset))
    partition = pyoasis.ApplePartition(il_offset, il_size)

    # +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    #  DECLARATION OF THE COUPLING FIELDS
    # +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    A_SST = pyoasis.Var("A_SST", partition, OASIS.IN)
    A_Ice_frac = pyoasis.Var("A_Ice_frac", partition, OASIS.IN)
    logging.debug('var_id A_SST, var_id A_Ice_frac {} {}'.format(A_SST._id, A_Ice_frac._id))
    if CO2_MODE:
        A_emissions = pyoasis.Var("A_emissions", partition, OASIS.IN)
        logging.debug('var_id A_emissions {}'.format(A_emissions._id))

    # +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    #         TERMINATION OF DEFINITION PHASE
    # +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    logging.debug('End of initialisation phase')

    comp.enddef()

    # +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    #  TIME STEP LOOP
    # +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    logging.debug('Timestep, field min, mean and max value')

    field_recv_A_SST = pyoasis.asarray(np.full(il_size, -1.0))
    field_recv_A_Ice_frac = pyoasis.asarray(np.full(il_size, -1.0))
    field_recv_A_emissions = pyoasis.asarray(np.full(il_size, -1.0))
    for itap_sec in range(0, RUN_LENGTH_SEC, COUPLING_INTERVAL):
        A_SST.get(itap_sec, field_recv_A_SST)
        A_Ice_frac.get(itap_sec, field_recv_A_Ice_frac)

        logging.debug('ITAP_SEC: {}'.format(itap_sec))
        logging.debug('A_SST -> {:.3e} {:.3e} {:.3e}'.format(
            np.min(field_recv_A_SST),
            np.mean(field_recv_A_SST),
            np.max(field_recv_A_SST)))
        logging.debug('A_Ice_frac -> {:.3e} {:.3e} {:.3e}'.format(
            np.min(field_recv_A_Ice_frac),
            np.mean(field_recv_A_Ice_frac),
            np.max(field_recv_A_Ice_frac)))
        if CO2_MODE:
            A_emissions.get(itap_sec, field_recv_A_emissions)
            logging.debug('A_emissions -> {:.3e} {:.3e} {:.3e}'.format(
                np.min(field_recv_A_emissions),
                np.mean(field_recv_A_emissions),
                np.max(field_recv_A_emissions)))
        logging.debug('--------------------------------------\n')

    # +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    #         TERMINATION
    # +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    logging.debug('End of the program')

    del comp
