#!/usr/bin/python -O

import re, os, sys, pacman, getopt

############################################################

# Define some classes we need
class Version:
  def __init__(self):
    self.version = None
    self.file = None

class Package:
  def __init__(self):
    self.name = None
    self.old = None
    self.new = None

############################################################
# Functions for walking the file trees
############################################################

def filesForRegexp(topdir, regexp):
  retval = []
  def matchfile(regexp, dirpath, namelist):
    for name in namelist:
      if (regexp.match(name)):
        retval.append(os.path.join(dirpath, name))
  os.path.walk(topdir, matchfile, regexp)
  return retval

def packagesInTree(topdir):
  return filesForRegexp(topdir, re.compile("^.*\.pkg\.tar\.gz$"))

def pkgbuildsInTree(topdir):
  return filesForRegexp(topdir, re.compile("^PKGBUILD$"))

############################################################
# Function for testing if two files are identical 
############################################################

def areFilesIdentical(file_a, file_b):
  command = "cmp '" + file_a + "' '" + file_b + "' >/dev/null"
  retval = os.system(command)
  if (retval == 0):
    return True
  return False

############################################################
# Function for fetching info from PKGBUILDs and packages
############################################################

def infoFromPackageFile(filename):
  pkg = pacman.load(filename)
  return pkg.name, pkg.version + "-" + pkg.release

def infoFromPkgbuildFile(filename):
  # open and source the file
  pf_stdin, pf_stdout = os.popen2("/bin/bash", 't', 0)
  print >>pf_stdin, ". " + filename

  # get pkgname
  print >>pf_stdin, 'echo $pkgname'
  pkgname = pf_stdout.readline().strip()

  # get pkgver
  print >>pf_stdin, 'echo $pkgver'
  pkgver = pf_stdout.readline().strip()

  # get pkgrel
  print >>pf_stdin, 'echo $pkgrel'
  pkgrel = pf_stdout.readline().strip()

  # clean up
  pf_stdin.close()
  pf_stdout.close()

  return pkgname, pkgver + "-" + pkgrel
  
############################################################
# Functions for doing the final steps of execution
############################################################

def execute(command):
  global switches
  print(command)
  if not (switches.get("-n") == True):
    os.system(command)

def copyFileToRepo(filename, repodir):
  destfile = os.path.join(repodir, os.path.basename(filename))
  command = "cp -p '" + filename + "' '" + destfile + "'"
  execute(command)

def deleteFile(filename):
  command = "rm '" + filename + "'"
  execute(command)

def runGensync(repo, pkgbuild):
  target = os.path.join(repo, os.path.basename(repo) + ".db.tar.gz")
  command = "gensync '" + pkgbuild_dir + "' '" + target + "'"
  execute(command)

############################################################
# Functions for error handling
############################################################

def warning(string):
  print >>sys.stderr, string + "\n"

had_error = 0
def error(string):
  global had_error
  warning(string)
  had_error = 1

############################################################
# MAIN
############################################################

# ARGUMENTS
#
# tupkgupdate [-n] [--delete] [--paranoid] <repo_dir> <pkgbuild_dir> <build_dir>

# First call getopt
switch_list,args_proper = getopt.getopt(sys.argv[1:], 'n',
		                        [ "delete", "paranoid" ])
switches = {}
for switch in switch_list:
  switches[switch[0]] = 1

# Then handle the remaining arguments
if (len(args_proper) < 3):
  print >>sys.stderr, "syntax: tupkgupdate [-n] [--delete] [--paranoid] <repo_dir> <pkgbuild_tree> <build_tree>"
  sys.exit(-1)

repo_dir, pkgbuild_dir, build_dir = args_proper

# Set up the lists and tables
packages = dict()
copy = list()
delete = list()

# PASS 1: PARSING/LOCATING
#  
# A) Go through the PKGBUILD tree
#    For each PKGBUILD, create a Package with new Version containing
#    parsed version and and None for file

a_files = pkgbuildsInTree(pkgbuild_dir)
for a_file in a_files:
  pkgname, ver = infoFromPkgbuildFile(a_file)

  # Error (and skip) if we encounter any invalid PKGBUILD files
  if (pkgname == None or ver == None):
    error("Pkgbuild '" + a_file + "' is invalid!")
    continue

  # Error (and skip) if we encounter any duplicate package names
  # in the PKGBUILDs
  if (packages.get(pkgname)):
    error("Pkgbuild '" + a_file + "' is a duplicate!")
    continue
  
  version = Version()
  version.version = ver
  version.file = None

  package = Package()
  package.name = pkgname
  package.new = version

  packages[pkgname] = package

# B) Go through the old repo dir
#    For each package file we encounter, create a Package with old
#    Version containing parsed version and filepath

b_files = packagesInTree(repo_dir)
for b_file in b_files:
  pkgname, ver = infoFromPackageFile(b_file)
  
  version = Version()
  version.version = ver
  version.file = b_file

  package = packages.get(pkgname)
  if (package == None):
    package = Package()
    package.name = pkgname
    packages[pkgname] = package
  package.old = version

# C) Go through the build tree
#    For each package file we encounter:
#      1 - look up the package name; if it fails, ignore the file (no error)
#      2 - if package.new == None, ignore the package (no error)
#      3 - if package.new.version doesn't match, then skip (no error)
#      4 - if package.new.file == None, point it to this file
#          otherwise, log an error (and skip)

c_files = packagesInTree(build_dir)
for c_file in c_files:
  pkgname, ver = infoFromPackageFile(c_file)

  # 1
  package = packages.get(pkgname)
  if (package == None):
    continue
  
  # 2
  if (package.new == None):
    continue

  # 3
  if (package.new.version != ver):
    continue

  # 4
  if (package.new.file == None):
    package.new.file = c_file
    continue
  else:
    error("Duplicate new file '" + c_file + "'")
    continue

# PASS 2: CHECKING
#
# Go through the package collection
#   1 - if package has no new, place its old file on the "delete" list
#   2 - if package has a new but no new.file, error and skip
#   3 - if package has no old, add new file to "copy" list into repo dir
#   4 - if old > new, error and skip
#   5 - if new == old, compare them and error and skip if files not the same
#   6 - add entry to "delete" list for old file and "copy" list for
#       new file into repo dir

for package in packages.values():
  # 1
  if (package.new == None):
    delete.append(package.old.file)
    continue

  # 2
  if (package.new.file == None):
    error("No new package supplied for " + package.name + " " + package.new.version + "!")
    continue

  # 3
  if (package.old == None):
    copy.append(package.new.file)
    continue

  # 4
  if (package.old.version < package.new.version):
    delete.append(package.old.file)
    copy.append(package.new.file)
    continue

  # 5
  if (package.old.version == package.new.version): 
    if (switches.get("--paranoid") == True):
      if not (areFilesIdentical(package.old.file, package.new.file)):
        warning("New package file with identical version '" + 
	  package.new.file + "' is different than the old one:")
	if (switches.get("--delete") == True):
          warning("  Deleting the new file.")
	else:
          warning("  Ignoring the new file.")
    continue

  # 6
  delete.append(package.old.file)
  copy.append(package.new.file)
  continue  

## IF WE HAVE HAD ANY ERRORS AT THIS POINT, ABORT! ##
if (had_error == 1):
  error("Aborting due to errors.")
  sys.exit(-1)

# PASS 3: EXECUTION
#
# Copy
for file in copy:
  copyFileToRepo(file, repo_dir)
# Delete (second, for safety's sake)
for file in delete:
  deleteFile(file)
# Run gensync to build the repo index
runGensync(repo_dir, pkgbuild_dir)