# P-2 MCS 260 15 Feb 2010 : colordb.py

# A color in a database is stored by two records.
# For example, the color red corresponds to (255, 0, 0) and is stored
# once as key "red" with value "16711680" (16711680 = 255*256**2) and
# once as key "16711680" with value "red".  Note that in both
# cases the type of key and value are always strings.
# The background window of turtle graphics displays the color
# and the name of the color appears as the title of the window.

import anydbm, turtle
coldb = anydbm.open('colors.dbm','c')
turtle.colormode(255)

print "hit enter to give a color code"
given = raw_input("or else type the name of a color : ")
if given == "":    # hitting enter leads to the empty string, case 1
   code = input("-> give a triplet (*,*,*), * in 0..255 : ")
   numb = code[0]*256**2 + code[1]*256 + code[2] # number representation
   turtle.bgcolor(code)                          # show color in background
   if str(numb) in coldb.keys():     # code already in database, case 1.1
      turtle.title(coldb[str(numb)]) # show the name of the color as title
   else:                             # code not in database, case 1.2
      name = raw_input("-> give a name for the color %s : " % str(code))
      turtle.title(name)             # show the name of the color as title
      coldb[str(numb)] = name        # store number as key, name as value
      coldb[name] = str(numb)        # store name as key, number as value
      print "-> added (" + name + "," + str(numb) + ") to the color database" 
else:              # user entered a name, case 2
   if given in coldb.keys(): # name is in database, case 2.1
      turtle.title(given)            # show the name of the color as title
      numb = eval(coldb[given])      # convert string into a number
      (q1,r1) = divmod(numb,256)     # first stage to tuple conversion
      (q2,r2) = divmod(q1,256)       # second stage to tuple conversion
      code = (q2,r2,r1)              # tuple code extracted from number
      turtle.bgcolor(code)           # show color in background of turtle
   else:                     # name is not in database, case 2.2
      print "-> \"" + given + "\" is not in the color database"
      prompt = "-> give a triplet (*,*,*), * in 0..255, for the color "
      code = raw_input(prompt + "\"%s\" : " % given)
      turtle.title(given)            # show the name of color as title
      evco = eval(code)              # convert tuple in string to tuple
      turtle.bgcolor(evco)           # show the color in background
      numb = evco[0]*256**2 + evco[1]*256 + evco[2] # number representation
      coldb[str(numb)] = given       # store number as key, name as value
      coldb[given] = str(numb)       # store value as key, number as value
      print "-> added (" + given + "," + str(numb) + ") to the color database" 
ans = raw_input("hit enter to exit") # to prevent turtle window from closing