import os, string

rootdir = ''
experiment = ''

################################################################################
# Set the globals
def setexperiment(root, exp):
    global rootdir, experiment
    
    rootdir = root
    experiment = exp
    
################################################################################
# Find the antenna number
def get_antenna_number(ant_name, uvdata):
    ant = 0
    for antenna in uvdata.antennas:
        ant = ant + 1
        if antenna == ant_name:
            return ant
    raise RuntimeError, "antenna not found!"
    return None

################################################################################
# Create handle for a given file
def check_data_file(prefix, telescope, extension):
    if telescope == '':
        fullpath = rootdir + '/' + prefix + '/' + experiment + extension
    else:
        fullpath = rootdir + '/' + prefix + '/' + experiment + '.' + telescope + extension
    if not os.path.isfile(fullpath):
        print 'Ooops - cant find file ' + fullpath
        if telescope == '':
            fullpath = rootdir + '/' + prefix + '/' + experiment + extension
        else:
            fullpath = rootdir + '/' + prefix + '/' + experiment + '.' + telescope + extension
    assert(os.path.isfile(fullpath))
    return fullpath

################################################################################
# Create handle for a given file
def check_root_file(filename):
    fullpath = rootdir + '/' + filename
    if not os.path.isfile(fullpath):
        fullpath = rootdir + '/' + filename
    print 'Checking file ' + fullpath
    assert(os.path.isfile(fullpath))
    return fullpath

################################################################################
# Checks if a given source is a primary phase reference
def isphaseref(source, primary_phaserefs):
    for phaseref in primary_phaserefs:
        if source == phaseref:
            return 1
    return 0

################################################################################
# Checks if a given source is present in the source table
def wasobserved(uvdata, source):
    for s in uvdata.sources:
        if source == s:
            return 1
    return 0

################################################################################
# Checks if user wants to do something or not
def yesno(autoyes, prompt):
    if autoyes:
        return True
    ans = raw_input(prompt)
    return (ans[0]=='y' or ans[0]=='Y')

################################################################################
# Returns an MJD from a date string from a header
def header_mjd(headerstring):
    year = string.atoi(headerstring[0:4])
    month = string.atoi(headerstring[5:7])
    day = string.atoi(headerstring[8:10])
    return year*367 - int(7*(year + int((month + 9)/12))/4) + int(275*month/9) + day - 678987

################################################################################
# Returns an MJD from a date string from a header
def getdoy(headerstring):
    year = string.atoi(headerstring[0:4])
    month = string.atoi(headerstring[5:7])
    day = string.atoi(headerstring[8:10])
    mjd1 = year*367 - int(7*(year + int((month + 9)/12))/4) + int(275*month/9) + day - 678987
    month = 1
    day = 1
    mjd0 = year*367 - int(7*(year + int((month + 9)/12))/4) + int(275*month/9) + day - 678987
    return mjd1 - mjd0 + 1