# Copyright (c) 2009-2011 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Package builder for the dev server."""

from __future__ import print_function

import os
import subprocess
import tempfile

from portage import dbapi
from portage import xpak
import cherrypy
import portage

import log_util


# Relative path to the wrapper directory inside the sysroot.
_SYSROOT_BUILD_BIN = 'build/bin'


def _SysrootCmd(sysroot, cmd):
  """Path to the sysroot wrapper for |cmd|.

  Args:
    sysroot: Path to the sysroot.
    cmd: Name of the command.
  """
  return os.path.join(sysroot, _SYSROOT_BUILD_BIN, cmd)


# Module-local log function.
def _Log(message, *args):
  return log_util.LogWithTag('BUILD', message, *args)


def _OutputOf(command):
  """Runs command, a list of arguments beginning with an executable.

  Args:
    command: A list of arguments, beginning with the executable

  Returns:
    The output of the command

  Raises:
    subprocess.CalledProcessError if the command fails
  """
  command_name = ' '.join(command)
  _Log('Executing: ' + command_name)

  p = subprocess.Popen(command, stdout=subprocess.PIPE)
  output_blob = p.communicate()[0]
  if p.returncode != 0:
    raise subprocess.CalledProcessError(p.returncode, command_name)
  return output_blob


def _FilterInstallMaskFromPackage(in_path, out_path):
  """Filter files matching DEFAULT_INSTALL_MASK out of a tarball.

  Args:
    in_path: Unfiltered tarball.
    out_path: Location to write filtered tarball.
  """

  # Grab metadata about package in xpak format.
  my_xpak = xpak.xpak_mem(xpak.tbz2(in_path).get_data())

  # Build list of files to exclude. The tar command uses a slightly
  # different exclude format than gmerge, so it needs to be adjusted
  # appropriately.
  masks = os.environ.get('DEFAULT_INSTALL_MASK', '').split()
  # Look for complete paths matching the specified pattern.  Leading slashes
  # are removed so that the paths are relative. Trailing slashes are removed
  # so that we delete the directory itself when the '/usr/include/' path is
  # given.
  masks = [mask.strip('/') for mask in masks]
  masks = ['--exclude="./%s"' % mask for mask in masks]
  excludes = '--anchored ' + ' '.join(masks)

  gmerge_dir = os.path.dirname(out_path)
  subprocess.check_call(['mkdir', '-p', gmerge_dir])

  tmpd = tempfile.mkdtemp()
  try:
    # Extract package to temporary directory (excluding masked files).
    cmd = ('pbzip2 -dc --ignore-trailing-garbage=1 %s'
           ' | sudo tar -x -C %s %s --wildcards')
    subprocess.check_call(cmd % (in_path, tmpd, excludes), shell=True)

    # Build filtered version of package.
    cmd = 'sudo tar -c --use-compress-program=pbzip2 -C %s . > %s'
    subprocess.check_call(cmd % (tmpd, out_path), shell=True)
  finally:
    subprocess.check_call(['sudo', 'rm', '-rf', tmpd])

  # Copy package metadata over to new package file.
  xpak.tbz2(out_path).recompose_mem(my_xpak)


def UpdateGmergeBinhost(sysroot, pkgs, deep):
  """Add packages to our gmerge-specific binhost.

  Files matching DEFAULT_INSTALL_MASK are not included in the tarball.
  """
  # Portage internal api expects the sysroot to ends with a '/'.
  sysroot = os.path.join(sysroot, '')

  gmerge_pkgdir = os.path.join(sysroot, 'gmerge-packages')
  stripped_link = os.path.join(sysroot, 'stripped-packages')

  # Create gmerge pkgdir and give us permission to write to it.
  subprocess.check_call(['sudo', 'mkdir', '-p', gmerge_pkgdir])
  subprocess.check_call(['sudo', 'ln', '-snf', os.path.basename(gmerge_pkgdir),
                         stripped_link])

  username = os.environ['PORTAGE_USERNAME']
  subprocess.check_call(['sudo', 'chown', username, gmerge_pkgdir])

  # Load databases.
  trees = portage.create_trees(config_root=sysroot, target_root=sysroot)
  vardb = trees[sysroot]['vartree'].dbapi
  bintree = trees[sysroot]['bintree']
  bintree.populate()
  gmerge_tree = dbapi.bintree.binarytree(sysroot, gmerge_pkgdir,
                                         settings=bintree.settings)
  gmerge_tree.populate()

  # The portage API here is subtle.  Results from these lookups are a pkg_str
  # object which derive from Python strings but attach some extra metadata
  # (like package file sizes and build times).  Helpers like __cmp__ aren't
  # changed, so the set logic can works.  But if you use a pkg_str from one
  # bintree in another, it can fail to resolve, while stripping off the extra
  # metadata allows the bintree to do the resolution internally.  Hence we
  # normalize all results here to strings.
  strmatches = lambda matches: set(str(x) for x in matches)
  if deep:
    # If we're in deep mode, fill in the binhost completely.
    gmerge_matches = strmatches(gmerge_tree.dbapi.cpv_all())
    bindb_matches = strmatches(bintree.dbapi.cpv_all())
    installed_matches = strmatches(vardb.cpv_all()) & bindb_matches
  else:
    # Otherwise, just fill in the requested package.
    gmerge_matches = set()
    bindb_matches = set()
    installed_matches = set()
    for pkg in pkgs:
      gmerge_matches.update(strmatches(gmerge_tree.dbapi.match(pkg)))
      bindb_matches.update(strmatches(bintree.dbapi.match(pkg)))
      installed_matches.update(strmatches(vardb.match(pkg)) & bindb_matches)

  # Remove any stale packages that exist in the local binhost but are not
  # installed anymore.
  if bindb_matches - installed_matches:
    subprocess.check_call([_SysrootCmd(sysroot, 'eclean'), '-d', 'packages'])

  # Remove any stale packages that exist in the gmerge binhost but are not
  # installed anymore.
  changed = False
  for pkg in gmerge_matches - installed_matches:
    gmerge_path = gmerge_tree.getname(pkg)
    if os.path.exists(gmerge_path):
      os.unlink(gmerge_path)
      changed = True

  # Copy any installed packages that have been rebuilt to the gmerge binhost.
  for pkg in installed_matches:
    build_time, = bintree.dbapi.aux_get(pkg, ['BUILD_TIME'])
    build_path = bintree.getname(pkg)
    gmerge_path = gmerge_tree.getname(pkg)

    # If a package exists in the gmerge binhost with the same build time,
    # don't rebuild it.
    if pkg in gmerge_matches and os.path.exists(gmerge_path):
      old_build_time, = gmerge_tree.dbapi.aux_get(pkg, ['BUILD_TIME'])
      if old_build_time == build_time:
        continue

    _Log('Filtering install mask from %s' % pkg)
    _FilterInstallMaskFromPackage(build_path, gmerge_path)
    changed = True

  # If the gmerge binhost was changed, update the Packages file to match.
  if changed:
    env_copy = os.environ.copy()
    env_copy['PKGDIR'] = gmerge_pkgdir
    cmd = [_SysrootCmd(sysroot, 'emaint'), '-f', 'binhost']
    subprocess.check_call(cmd, env=env_copy)

  return bool(installed_matches)


class Builder(object):
  """Builds packages for the devserver."""

  def _ShouldBeWorkedOn(self, board, pkg):
    """Is pkg a package that could be worked on, but is not?"""
    if pkg in _OutputOf(['cros_workon', '--board=' + board, 'list']):
      return False

    # If it's in the list of possible workon targets, we should be working on it
    return pkg in _OutputOf([
        'cros_workon', '--board=' + board, '--all', 'list'])

  def SetError(self, text):
    cherrypy.response.status = 500
    _Log(text)
    return text

  def Build(self, board, pkg, additional_args):
    """Handles a build request from the cherrypy server."""
    _Log('Additional build request arguments: ' + str(additional_args))

    def _AppendStrToEnvVar(env, var, additional_string):
      env[var] = env.get(var, '') + ' ' + additional_string
      _Log('%s flags modified to %s' % (var, env[var]))

    env_copy = os.environ.copy()
    if 'use' in additional_args:
      _AppendStrToEnvVar(env_copy, 'USE', additional_args['use'])

    if 'features' in additional_args:
      _AppendStrToEnvVar(env_copy, 'FEATURES', additional_args['features'])

    try:
      if (not additional_args.get('accept_stable')
          and self._ShouldBeWorkedOn(board, pkg)):
        return self.SetError(
            'Package is not cros_workon\'d on the devserver machine.\n'
            'Either start working on the package or pass --accept_stable '
            'to gmerge')

      sysroot = '/build/%s/' % board
      # If user did not supply -n, we want to rebuild the package.
      usepkg = additional_args.get('usepkg')
      if not usepkg:
        rc = subprocess.call(
            [_SysrootCmd(sysroot, 'emerge'), pkg],
            env=env_copy)
        if rc != 0:
          return self.SetError('Could not emerge ' + pkg)

      # Sync gmerge binhost.
      deep = additional_args.get('deep')
      if not UpdateGmergeBinhost(sysroot, [pkg], deep):
        return self.SetError('Package %s is not installed' % pkg)

      return 'Success\n'
    except OSError, e:
      return self.SetError('Could not execute build command: ' + str(e))