import sys
import simplejson

def parse_input():
    """
Used to get the information from the calling process
"""
    data = sys.stdin.readline()
    return simplejson.loads(data)

def complete(data):
    """
Prints a JSON dictionary to stdout to communicate status to the calling
process.
"""
    print simplejson.dumps(data)

def original_metrics(original):
    # Calculate the tallest and widest glyph in ems
    glyphs = list(original.glyphs())
    ascent = max([r.boundingBox()[3] for r in glyphs])
    descent = -1 * min([r.boundingBox()[1] for r in glyphs])

    results = {}
    results['os2_winascent'] = original.os2_winascent + ascent
    results['os2_windescent'] = original.os2_windescent + descent

    results['os2_typoascent'] = original.os2_typoascent + original.ascent
    results['os2_typodescent'] = original.os2_typodescent + (-1 * original.descent)

    results['hhea_ascent'] = original.hhea_ascent + ascent
    results['hhea_descent'] = original.hhea_descent + (-1 * descent)

    # It seems to adjust the underline position and thickness
    results['upos'] = float(original.upos)

    return results

def lossless_save(original_metrics, font, output_filename):
    """
For some reason fontforge likes to modify things in it's output files, such
as underline position. So we are undoing it to maintain the integrity of
the font.
"""
    font.os2_winascent_add = 0 # turns off the offset, stupid naming if you ask me.
    font.os2_winascent = original_metrics['os2_winascent']
    font.os2_windescent_add = 0
    font.os2_windescent = original_metrics['os2_windescent']

    font.os2_typoascent_add = 0
    font.os2_typoascent = original_metrics['os2_typoascent']
    font.os2_typodescent_add = 0
    font.os2_typodescent = original_metrics['os2_typodescent']

    font.hhea_ascent_add = 0
    font.hhea_ascent = original_metrics['hhea_ascent']
    font.hhea_descent_add = 0
    font.hhea_descent = original_metrics['hhea_descent']

    # Force the font family name to be correct.
    font.familyname = font.fullname.split('-')[0]

    # It seems to adjust the underline position and thickness
    font.upos = original_metrics['upos']

    font.generate(output_filename)