import taskutil

def ptgs2ann(ptgs, diam, ann, color = 'green'):
    """
    Given a list of pointings ptgs, make a kvis annotation file ann with a
    cross and circle of diameter diam (an angle qa) at each pointing.
    """
    try:
        anf = open(ann, 'w')
    except:
        print "Error opening %s for writing!" % ann
        return

    anf.write("color %s\n" % color)

    myf = taskutil.get_global_namespace()
    qa = myf['qa']
    if type(diam) == str:
        diam = qa.quantity(diam)
    d = 0.5 * qa.convert(diam, 'deg')['value']
    crosssize = 0.1 * d
    for i in xrange(0, len(ptgs)):
        epoch, x, y = direction_splitter(ptgs[i])
        wxy = "w %10.6f %10.6f" % (x['value'] - crosssize, y['value'] + crosssize)
        anf.write("text   %s %d # %s\n" % (wxy, i, ptgs[i])) 
        wxy = "w %10.6f %10.6f" % (x['value'], y['value'])
        anf.write("cross  %s  %8.6f %8.6f # %d\n" % (wxy, crosssize, crosssize, i))
        anf.write("circle %s %9.6f          # %d\n" % (wxy, d, i))
    anf.close()
        
def direction_splitter(direction):
    """
    Given a direction, return its epoch, x, and y parts.  Epoch will be ''
    if absent, or '%s ' % epoch if present.  x and y will be angle qa's in
    degrees.
    """
    dirl = direction.split()
    if len(dirl) == 3:
        epoch = dirl[0] + ' '
    else:
        epoch = ''
    myf = taskutil.get_global_namespace()
    qa = myf['qa']
    x, y = map(qa.toangle, dirl[-2:])
    return epoch, qa.convert(x, 'deg'), qa.convert(y, 'deg')