#!/usr/bin/env python
"""!Functions called automatically before a cycle is launched.

This module contains utility functions for the hwrf.launcher.launch()
prelaunch argument.  These functions edit the configuration of an
individual cycle before the cycle starts."""

import os
import hwrf.numerics
import produtil.fileop
from produtil.log import jlogger

##@var __all__
# Symbols exported by "from hwrf.prelaunch import *"
__all__=['prelaunch_ungrib','prelaunch_rsmc','prelaunch_basin']

def prelaunch_wind(conf,logger):
    """!Disables relocation and GSI if the wind is below some threshold."""
    threshold=conf.getint('config','min_wind_for_init',0)
    wind=conf.syndat.wmax
    if wind<threshold:
        jlogger.info('Wind %d < %d so disabling GSI and relocation.'%(
                wind,threshold))
        logger.info('Wind %d<%d - run_gsi, run_relocation and run_ens_relocation overridden to "no"'%(
                wind,threshold))
        conf.set('config','run_gsi','no')
        conf.set('config','run_relocation','no')
        conf.set('config','run_ens_relocation','no')

def prelaunch_ensid(conf,logger):
    """!Changes the ungrib item and item2 based on the ensemble ID.
    This is used to ensure ensemble member 0 uses the GEFS control,
    which has a different item in the hwrf.input.DataCatalog."""
    ens_overrides=conf.getbool('prelaunch','ensid_overrides')
    if not ens_overrides:
        logger.info('Ensemble ID overrides are disabled.')
        return
    ens=conf.getint('config','ENS',99)
    item=conf.get('ungrib','item_E%02d'%ens,'')
    item2=conf.get('ungrib','item2_E%02d'%ens,'')
    if item:
        logger.info('Overriding [ungrib] item=item_E%02d=%s'%(ens,item))
        conf.set('ungrib','item',item)
    if item2:
        logger.info('Overriding [ungrib] item2=item2_E%02d=%s'%(ens,item2))
        conf.set('ungrib','item2',item2)

def prelaunch_ungrib(conf,logger,cycle):
    """!Change the ungrib table based on the year.

    Modifies the tbl entry in the [ungrib] section based on the year
    if a tbl$YEAR is available for the year of the cycle being run.
    @param conf the hwrf.config.HWRFConfig to modify
    @param logger the logging.Logger for log messages
    @param cycle the cycle being run."""
    ungrib_overrides=conf.getbool('prelaunch','ungrib_overrides') 
    if not ungrib_overrides:
        logger.info('Ungrib overrides are disabled.')
        return

    # We're in an exhwrf_launch job, not in run_hwrf.py
    cyc=hwrf.numerics.to_datetime(cycle)   # the cycle as a datetime
   
    # Replace [ungrib] tbl with per-year data
    tblYEARname=cyc.strftime("tbl%Y")  # ie.: tbl2011 for 2011090418
    tblYEARvalue=conf.get("ungrib",tblYEARname,'')
    if tblYEARvalue:
        conf.set("ungrib",'tbl',tblYEARvalue)

def prelaunch_rsmc(conf,logger,cycle):
    """!Modifies the configuration for the RSMC (JTWC, NHC, etc.)
    
    Modifies the configuration to work differently for JTWC and NHC
    storms.  Searches for the rsmc_conf option in the [prelaunch]
    section for the name of a configuration file to read, and reads it
    if it exists.
    @param conf the hwrf.config.HWRFConfig to modify
    @param logger the logging.Logger for log messages
    @param cycle the cycle being run."""
    rsmc_overrides=conf.getbool('prelaunch','rsmc_overrides')
    if not rsmc_overrides:
        logger.info('RSMC overrides are disabled.')
        return

    vit=conf.syndat
    rsmc=str(vit.center).upper()
    rfile=conf.strinterp('prelaunch','{rsmc_conf}',RSMC=rsmc)
    if not produtil.fileop.isnonempty(rfile):
        logger.warning('%s: RSMC override file is empty or non-existent'
                       %(rfile,))
    conf.read(rfile)

def prelaunch_basin(conf,logger,cycle):
    """!Modifies the configuration for the basin.
    
    @anchor prelaunch_basin_main
    Modifies the configuration to work differently for each basin.
    Searches for the basin_conf option in the [prelaunch] section for
    the name of a configuration file to read, and reads it if it
    exists.  If it does not exist, searches for the no_basin_conf
    section in [prelaunch] and runs that instead, if it exists.
    @param conf the hwrf.config.HWRFConfig to modify
    @param logger the logging.Logger for log messages
    @param cycle the cycle being run."""
    basin_overrides=conf.getbool('prelaunch','basin_overrides')
    if not basin_overrides:
        logger.info('Basin overrides are disabled.')
        return

    vit=conf.syndat
    if vit is None:
        logger.warning('Cannot use basin overrides - conf.syndat is None')
        return
    bfile=conf.strinterp('prelaunch','{basin_conf}',vit=vit)
    nfile=conf.strinterp('prelaunch','{no_basin_conf}',vit=vit)

    if os.path.exists(bfile):
        logger.warning('%s: reading basin override file'%(bfile,))
        conf.read(bfile)
    elif os.path.exists(nfile):
        logger.warning('%s: basin override enabled, but file is '
                       'missing or empty; will read %s instead.'
                       %(bfile,nfile))
        conf.read(nfile)
    else:
        logger.warning('%s: basin override enabled, and no "no_basin_file"'
                       'is available at %s; will not override defaults.'
                       %(bfile,nfile))