#!/usr/bin/python -u

"""critter.cgi

A web service for generating critters.

Requires the Python Imaging Library 
"""

__author__ = "Joe Gregorio (joe@bitworking.org)"
__copyright__ = "Copyright 2007, Joe Gregorio"
__contributors__ = []
__version__ = "1.0.0 $Rev:  $"
__license__ = "MIT"
__history__ = """

"""

import cgi
import cgitb
import sys
import os
import time
cgitb.enable()

import Image, ImageDraw, ImageFile
import StringIO
import urllib
import sha

def etag(critterid):
    file_version = os.stat(sys.argv[0]).st_mtime
    etag = sha.sha(critterid)
    etag.update(str(file_version))
    return '"%s"' % etag.hexdigest()


sizename = {
    "small": "-smaller",
    "medium": "-small",
    "large": ""
}

def compose(foot, face, hair, eyes, mouth, size):
    size = sizename[size]
    f = Image.open("foot%0d%s.png" % (foot, size)) 
    a = Image.open("face%0d%s.png" % (face, size)) 
    h = Image.open("hair%0d%s.png" % (hair, size))
    e = Image.open("eyes%0d%s.png" % (eyes, size))
    m = Image.open("mouth%0d%s.png" % (mouth, size))

    f.paste(a, (0,0), a)
    f.paste(h, (0,0), h)
    f.paste(e, (0,0), e)
    f.paste(m, (0,0), m)
    out = StringIO.StringIO()
    f.save(out, "PNG")
    return out.getvalue()

def not_modified():
    print "Status: 304 Not Modified"
    print ""
    sys.exit()

def ok(critterid):
    print "Status: 200 Ok"
    print "Content-type: image/png"
    #print "Vary: Accept-Encoding"
    print 'ETag: %s' % etag(critterid) 
    print ""

def error(status="Status: 400 Bad Request"):
    print "Content-type: image/png"
    print "X-Other: testing"
    print status 
    print ""
    sys.exit()

if not os.environ['REQUEST_METHOD'] in ['GET', 'HEAD']:
    error("Status: 405 Method Not Allowed")
if_none_match = os.environ.get('HTTP_IF_NONE_MATCH', '')

query = cgi.parse_qs(os.environ.get('QUERY_STRING', ''))
size = query.get('size', ['medium'])[0]
#f = open("log", "w+")
#f.write(repr(size))
#f.write("\n")
#f.close()
if size not in ['small', 'medium', 'large']:
    size = 'medium'
hash = sha.sha(os.environ.get('PATH_INFO', '1')).hexdigest()
critterparts = [(int(hash[i], 16) % 8) + 1 for i in range(5)]
critterparts.append(size)

critterid = "".join([str(n) for n in critterparts])  

if if_none_match and etag(critterid) == if_none_match:
    not_modified()

image_data = compose(*critterparts)
ok(critterid)
sys.stdout.write(image_data)