#!/usr/bin/python
import sys
import string
'''
A python script to extract information from unmet listing
'''
def parsepackage(p):
	'''
	The format of p is as below (p is a list of lines)
	------------------------------------------------
	<package> version <version> has an unmet dep:
	Depends: <dependency>
	Depends: <dependency>
	..
	Recommends: <recommend dependency>
	..
	Suggests: <suggests dependency>
	..
	------------------------------------------------
	
	returns a list [package,[depends list],[recommend list],[suggest list]]
	'''

	listlen=len(p)
	packagename=''
	deplist=[]
	reclist=[]
	suglist=[]
	
	if listlen>0:
		packagename=p[0].split()[0]

	for i in range(1,listlen):
		if p[i] == '':
			continue
		lineparse=p[i].split()
		if lineparse[0] == 'Depends:':
			deplist.append(lineparse[1])
		elif lineparse[0] == 'Suggests:':
                        suglist.append(lineparse[1])
		elif lineparse[0] == 'Recommends:':
                        reclist.append(lineparse[1])
		elif lineparse[0] == 'Breaks:':
			continue
		else:
			print "Debug: Dont understand %s" %(p[i])
	return [packagename,deplist,reclist,suglist]

def usage_exit():
	print "Ver 0.1\nUsage \n%s <option>  <package> <unmet_listing_file>" %(sys.argv[0])
	print "Option can be one of the following"
	print " search : search for the <package> in listing and print full listing"
	print " depends : find dependencies of <package>"
	print " rdepends : find which packages depend on <package>"
	print " suggests : find suggested packages for <package>"
	print " rsuggests : find which packages suggest <package>"
	print " recommends : find recommended packages for <package>"
	print " rrecommends : find which packages recommend <package>"
        sys.exit(1)

cmd_args= len(sys.argv)
if cmd_args != 4:
	usage_exit()


option=sys.argv[1]
if not option in ['search','depends','rdepends','suggests','rsuggests','recommends','rrecommends']:
	print "Unknown criteria '%s'" %(option)
	usage_exit()

pkgname=sys.argv[2]

#Now read unmet listing into memory
try:
	unmet_fd=open(sys.argv[3])
	unmet_list=unmet_fd.read()
	unmet_fd.close()
except IOError:
	print "%s does not exist" % (sys.argv[3])
	sys.exit(2)

#create a list of packages
packagelist=unmet_list.split("Package")
#The first one is empty.. remove it"
packagelist=packagelist[1:]

for package in packagelist:
	parsedlist=parsepackage(package.split("\n"))
	if option=='search':
		if pkgname in parsedlist[0]:
			print "Package: %s" %(package)
	elif option=='depends':
		if pkgname in parsedlist[0]:
			print "Dependencies of %s:\n%s\n" %(parsedlist[0],string.join(parsedlist[1],"\n"))
	elif option=='rdepends':
		if pkgname in string.join(parsedlist[1]," "):
			print parsedlist[0]
	elif option=='suggests':
		if pkgname in parsedlist[0]:
                        print "Suggested packages of %s:\n%s\n" %(parsedlist[0],string.join(parsedlist[3],"\n"))
	elif option=='rsuggests':
		if pkgname in string.join(parsedlist[3]," "):
                        print parsedlist[0]
	elif option=='recommends':
		if pkgname in parsedlist[0]:
                        print "Recommended packages of %s:\n%s\n" %(parsedlist[0],string.join(parsedlist[2],"\n"))
	else:
		# rrecommends
		if pkgname in string.join(parsedlist[2]," "):
                        print parsedlist[0]

sys.exit(0)