#!/usr/bin/env python
# Copyright (c) 2013 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""
Tool to perform checkouts in one easy command line!

Usage:
  fetch <config> [--property=value [--property2=value2 ...]]

This script is a wrapper around various version control and repository
checkout commands. It requires a |config| name, fetches data from that
config in depot_tools/fetch_configs, and then performs all necessary inits,
checkouts, pulls, fetches, etc.

Optional arguments may be passed on the command line in key-value pairs.
These parameters will be passed through to the config's main method.
"""

import json
import optparse
import os
import pipes
import subprocess
import sys
import textwrap

import git_common

from distutils import spawn


SCRIPT_PATH = os.path.dirname(os.path.abspath(__file__))

#################################################
# Checkout class definitions.
#################################################
class Checkout(object):
  """Base class for implementing different types of checkouts.

  Attributes:
    |base|: the absolute path of the directory in which this script is run.
    |spec|: the spec for this checkout as returned by the config. Different
        subclasses will expect different keys in this dictionary.
    |root|: the directory into which the checkout will be performed, as returned
        by the config. This is a relative path from |base|.
  """
  def __init__(self, options, spec, root):
    self.base = os.getcwd()
    self.options = options
    self.spec = spec
    self.root = root

  def exists(self):
    pass

  def init(self):
    pass

  def sync(self):
    pass

  def run(self, cmd, return_stdout=False, **kwargs):
    print 'Running: %s' % (' '.join(pipes.quote(x) for x in cmd))
    if self.options.dry_run:
      return ''
    if return_stdout:
      return subprocess.check_output(cmd, **kwargs)
    else:
      subprocess.check_call(cmd, **kwargs)
      return ''


class GclientCheckout(Checkout):

  def run_gclient(self, *cmd, **kwargs):
    if not spawn.find_executable('gclient'):
      cmd_prefix = (sys.executable, os.path.join(SCRIPT_PATH, 'gclient.py'))
    else:
      cmd_prefix = ('gclient',)
    return self.run(cmd_prefix + cmd, **kwargs)

  def exists(self):
    try:
      gclient_root = self.run_gclient('root', return_stdout=True).strip()
      return (os.path.exists(os.path.join(gclient_root, '.gclient')) or
              os.path.exists(os.path.join(os.getcwd(), self.root)))
    except subprocess.CalledProcessError:
      pass
    return os.path.exists(os.path.join(os.getcwd(), self.root))


class GitCheckout(Checkout):

  def run_git(self, *cmd, **kwargs):
    print 'Running: git %s' % (' '.join(pipes.quote(x) for x in cmd))
    if self.options.dry_run:
      return ''
    return git_common.run(*cmd, **kwargs)


class GclientGitCheckout(GclientCheckout, GitCheckout):

  def __init__(self, options, spec, root):
    super(GclientGitCheckout, self).__init__(options, spec, root)
    assert 'solutions' in self.spec

  def _format_spec(self):
    def _format_literal(lit):
      if isinstance(lit, basestring):
        return '"%s"' % lit
      if isinstance(lit, list):
        return '[%s]' % ', '.join(_format_literal(i) for i in lit)
      return '%r' % lit
    soln_strings = []
    for soln in self.spec['solutions']:
      soln_string= '\n'.join('    "%s": %s,' % (key, _format_literal(value))
                             for key, value in soln.iteritems())
      soln_strings.append('  {\n%s\n  },' % soln_string)
    gclient_spec = 'solutions = [\n%s\n]\n' % '\n'.join(soln_strings)
    extra_keys = ['target_os', 'target_os_only', 'cache_dir']
    gclient_spec += ''.join('%s = %s\n' % (key, _format_literal(self.spec[key]))
                             for key in extra_keys if key in self.spec)
    return gclient_spec

  def init(self):
    # Configure and do the gclient checkout.
    self.run_gclient('config', '--spec', self._format_spec())
    sync_cmd = ['sync']
    if self.options.nohooks:
      sync_cmd.append('--nohooks')
    if self.options.no_history:
      sync_cmd.append('--no-history')
    if self.spec.get('with_branch_heads', False):
      sync_cmd.append('--with_branch_heads')
    self.run_gclient(*sync_cmd)

    # Configure git.
    wd = os.path.join(self.base, self.root)
    if self.options.dry_run:
      print 'cd %s' % wd
    self.run_git(
        'submodule', 'foreach',
        'git config -f $toplevel/.git/config submodule.$name.ignore all',
        cwd=wd)
    if not self.options.no_history:
      self.run_git(
          'config', '--add', 'remote.origin.fetch',
          '+refs/tags/*:refs/tags/*', cwd=wd)
    self.run_git('config', 'diff.ignoreSubmodules', 'all', cwd=wd)


CHECKOUT_TYPE_MAP = {
    'gclient':         GclientCheckout,
    'gclient_git':     GclientGitCheckout,
    'git':             GitCheckout,
}


def CheckoutFactory(type_name, options, spec, root):
  """Factory to build Checkout class instances."""
  class_ = CHECKOUT_TYPE_MAP.get(type_name)
  if not class_:
    raise KeyError('unrecognized checkout type: %s' % type_name)
  return class_(options, spec, root)


#################################################
# Utility function and file entry point.
#################################################
def usage(msg=None):
  """Print help and exit."""
  if msg:
    print 'Error:', msg

  print textwrap.dedent("""\
    usage: %s [options] <config> [--property=value [--property2=value2 ...]]

    This script can be used to download the Chromium sources. See
    http://www.chromium.org/developers/how-tos/get-the-code
    for full usage instructions.

    Valid options:
       -h, --help, help   Print this message.
       --nohooks          Don't run hooks after checkout.
       --force            (dangerous) Don't look for existing .gclient file.
       -n, --dry-run      Don't run commands, only print them.
       --no-history       Perform shallow clones, don't fetch the full git history.

    Valid fetch configs:""") % os.path.basename(sys.argv[0])

  configs_dir = os.path.join(SCRIPT_PATH, 'fetch_configs')
  configs = [f[:-3] for f in os.listdir(configs_dir) if f.endswith('.py')]
  configs.sort()
  for fname in configs:
    print '  ' + fname

  sys.exit(bool(msg))


def handle_args(argv):
  """Gets the config name from the command line arguments."""
  if len(argv) <= 1:
    usage('Must specify a config.')
  if argv[1] in ('-h', '--help', 'help'):
    usage()

  dry_run = False
  nohooks = False
  no_history = False
  force = False
  while len(argv) >= 2:
    arg = argv[1]
    if not arg.startswith('-'):
      break
    argv.pop(1)
    if arg in ('-n', '--dry-run'):
      dry_run = True
    elif arg == '--nohooks':
      nohooks = True
    elif arg == '--no-history':
      no_history = True
    elif arg == '--force':
      force = True
    else:
      usage('Invalid option %s.' % arg)

  def looks_like_arg(arg):
    return arg.startswith('--') and arg.count('=') == 1

  bad_parms = [x for x in argv[2:] if not looks_like_arg(x)]
  if bad_parms:
    usage('Got bad arguments %s' % bad_parms)

  config = argv[1]
  props = argv[2:]
  return (
      optparse.Values({
        'dry_run': dry_run,
        'nohooks': nohooks,
        'no_history': no_history,
        'force': force}),
      config,
      props)


def run_config_fetch(config, props, aliased=False):
  """Invoke a config's fetch method with the passed-through args
  and return its json output as a python object."""
  config_path = os.path.abspath(
      os.path.join(SCRIPT_PATH, 'fetch_configs', config))
  if not os.path.exists(config_path + '.py'):
    print "Could not find a config for %s" % config
    sys.exit(1)

  cmd = [sys.executable, config_path + '.py', 'fetch'] + props
  result = subprocess.Popen(cmd, stdout=subprocess.PIPE).communicate()[0]

  spec = json.loads(result)
  if 'alias' in spec:
    assert not aliased
    return run_config_fetch(
        spec['alias']['config'], spec['alias']['props'] + props, aliased=True)
  cmd = [sys.executable, config_path + '.py', 'root']
  result = subprocess.Popen(cmd, stdout=subprocess.PIPE).communicate()[0]
  root = json.loads(result)
  return spec, root


def run(options, spec, root):
  """Perform a checkout with the given type and configuration.

    Args:
      options: Options instance.
      spec: Checkout configuration returned by the the config's fetch_spec
          method (checkout type, repository url, etc.).
      root: The directory into which the repo expects to be checkout out.
  """
  assert 'type' in spec
  checkout_type = spec['type']
  checkout_spec = spec['%s_spec' % checkout_type]
  try:
    checkout = CheckoutFactory(checkout_type, options, checkout_spec, root)
  except KeyError:
    return 1
  if not options.force and checkout.exists():
    print 'Your current directory appears to already contain, or be part of, '
    print 'a checkout. "fetch" is used only to get new checkouts. Use '
    print '"gclient sync" to update existing checkouts.'
    print
    print 'Fetch also does not yet deal with partial checkouts, so if fetch'
    print 'failed, delete the checkout and start over (crbug.com/230691).'
    return 1
  return checkout.init()


def main():
  options, config, props = handle_args(sys.argv)
  spec, root = run_config_fetch(config, props)
  return run(options, spec, root)


if __name__ == '__main__':
  try:
    sys.exit(main())
  except KeyboardInterrupt:
    sys.stderr.write('interrupted\n')
    sys.exit(1)