#!/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.
"""

from __future__ import print_function

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:
      try:
        subprocess.check_call(cmd, **kwargs)
      except subprocess.CalledProcessError as e:
        # If the subprocess failed, it likely emitted its own distress message
        # already - don't scroll that message off the screen with a stack trace
        # from this program as well. Emit a terse message and bail out here;
        # otherwise a later step will try doing more work and may hide the
        # subprocess message.
        print('Subprocess failed with return code %d.' % e.returncode)
        sys.exit(e.returncode)
      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, str) or (sys.version_info.major == 2 and
                                  isinstance(lit, unicode)):
        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.items())
      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)