#!/usr/bin/env python
# Construct a chroot environment based on a config file.

import garstowlib, sys, os

class Config:
	def __init__(self):
		self.root = None
		self.packages = []
		self.copy = []

	def load(self, fn):
		f = open(fn)
		for l in f.readlines():
			l = l.strip()
			if l == "" or l[0] == "#": continue
			(c, v) = l.split(" ", 1)
			if c == "include":
				self.load(v)
			elif c == "root":
				self.root = v
			elif c == "package":
				self.packages.append(v)
			elif c == "copy":
				self.copy.append(v)
		f.close()

def die(s):
	print s
	sys.exit(1)

def cmd(s):
	print "==> " + s
	result = os.system(s)
	if (result >> 8) != 0:
		die("command failed: " + s)

def build_chroot(fn):
	conf = Config()
	conf.load(fn)

	packages = {}
	for p in conf.packages:
		packages[p] = None
		for d in garstowlib.get_deps_rec(p):
			packages[d] = None
	
	copylist = []

	for l in conf.copy:
		copylist.append(l)

	for p in packages.keys():
		v = garstowlib.get_installed_version(p)
		if v is None:
			die("package " + p + " not installed")
		packages[p] = p + "-" + v
		copylist.append(garstowlib.get_packages_dir() + "/" + packages[p])

	copylist.sort()

	# FIXME broken for filenames with spaces in (owing to use of shell)
	cmd("mkdir -p " + conf.root)
	cmd("tar -C / -cpf - " + " ".join([c[1:] for c in copylist]) + " | tar -C " + conf.root + " --same-owner -xpf -")
	for p in packages.keys():
		dest = conf.root + garstowlib.get_packages_dir() + "/" + p
		cmd("rm -f " + dest)
		cmd("ln -sf " + packages[p] + " " + dest)
	cmd("stow -t " + conf.root + garstowlib.get_stow_dir() + " -d " + conf.root + garstowlib.get_packages_dir() + " " + " ".join(packages.keys()))

if __name__ == "__main__":
	for fn in sys.argv[1:]:
		build_chroot(fn)
	sys.exit(0)