#!/usr/bin/env python

# Copyright 2016 The LUCI Authors. All rights reserved.
# Use of this source code is governed under the Apache License, Version 2.0
# that can be found in the LICENSE file.

"""Bootstrap script to clone and forward to the recipe engine tool.

***********************************************************************
** DO NOT MODIFY EXCEPT IN THE PER-REPO CONFIGURATION SECTION BELOW. **
***********************************************************************

This is a copy of https://github.com/luci/recipes-py/blob/master/doc/recipes.py.
To fix bugs, fix in the github repo then copy it back to here and fix the
PER-REPO CONFIGURATION section to look like this one.
"""

import os

#### PER-REPO CONFIGURATION (editable) ####
# The root of the repository relative to the directory of this file.
REPO_ROOT = ''
# The path of the recipes.cfg file relative to the root of the repository.
RECIPES_CFG = os.path.join('infra', 'config', 'recipes.cfg')
#### END PER-REPO CONFIGURATION ####

BOOTSTRAP_VERSION = 1

import argparse
import ast
import json
import logging
import random
import re
import subprocess
import sys
import time
import traceback

from cStringIO import StringIO


def parse(repo_root, recipes_cfg_path):
  """Parse is transitional code which parses a recipes.cfg file as either jsonpb
  or as textpb.

  Args:
    repo_root (str) - native path to the root of the repo we're trying to run
      recipes for.
    recipes_cfg_path (str) - native path to the recipes.cfg file to process.

  Returns (as tuple):
    engine_url (str) - the url to the engine repo we want to use.
    engine_revision (str) - the git revision for the engine to get.
    engine_subpath (str) - the subdirectory in the engine repo we should use to
      find it's recipes.py entrypoint. This is here for completeness, but will
      essentially always be empty. It would be used if the recipes-py repo was
      merged as a subdirectory of some other repo and you depended on that
      subdirectory.
    recipes_path (str) - native path to where the recipes live inside of the
      current repo (i.e. the folder containing `recipes/` and/or
      `recipe_modules`)
  """
  with open(recipes_cfg_path, 'rU') as fh:
    data = fh.read()

  if data.lstrip().startswith('{'):
    pb = json.loads(data)
    engine = next(
      (d for d in pb['deps'] if d['project_id'] == 'recipe_engine'), None)
    if engine is None:
      raise ValueError('could not find recipe_engine dep in %r'
                       % recipes_cfg_path)
    engine_url = engine['url']
    engine_revision = engine['revision']
    engine_subpath = engine.get('path_override', '')
    recipes_path = pb.get('recipes_path', '')
  else:
    def get_unique(things):
      if len(things) == 1:
        return things[0]
      elif len(things) == 0:
        raise ValueError("Expected to get one thing, but dinna get none.")
      else:
        logging.warn('Expected to get one thing, but got a bunch: %s\n%s' %
                     (things, traceback.format_stack()))
        return things[0]

    protobuf = parse_textpb(StringIO(data))

    engine_buf = get_unique([
        b for b in protobuf.get('deps', [])
        if b.get('project_id') == ['recipe_engine'] ])
    engine_url = get_unique(engine_buf['url'])
    engine_revision = get_unique(engine_buf['revision'])
    engine_subpath = (get_unique(engine_buf.get('path_override', ['']))
                      .replace('/', os.path.sep))
    recipes_path = get_unique(protobuf.get('recipes_path', ['']))

  recipes_path = os.path.join(repo_root, recipes_path.replace('/', os.path.sep))
  return engine_url, engine_revision, engine_subpath, recipes_path


def parse_textpb(fh):
  """Parse the protobuf text format just well enough to understand recipes.cfg.

  We don't use the protobuf library because we want to be as self-contained
  as possible in this bootstrap, so it can be simply vendored into a client
  repo.

  We assume all fields are repeated since we don't have a proto spec to work
  with.

  Args:
    fh: a filehandle containing the text format protobuf.
  Returns:
    A recursive dictionary of lists.
  """
  def parse_atom(field, text):
    if text == 'true':
      return True
    if text == 'false':
      return False

    # repo_type is an enum. Since it does not have quotes,
    # invoking literal_eval would fail.
    if field == 'repo_type':
      return text

    return ast.literal_eval(text)

  ret = {}
  for line in fh:
    line = line.strip()
    m = re.match(r'(\w+)\s*:\s*(.*)', line)
    if m:
      ret.setdefault(m.group(1), []).append(parse_atom(m.group(1), m.group(2)))
      continue

    m = re.match(r'(\w+)\s*{', line)
    if m:
      subparse = parse_textpb(fh)
      ret.setdefault(m.group(1), []).append(subparse)
      continue

    if line == '}':
      return ret
    if line == '':
      continue

    raise ValueError('Could not understand line: <%s>' % line)

  return ret


def _subprocess_call(argv, **kwargs):
  logging.info('Running %r', argv)
  return subprocess.call(argv, **kwargs)


def _subprocess_check_call(argv, **kwargs):
  logging.info('Running %r', argv)
  subprocess.check_call(argv, **kwargs)


def find_engine_override(argv):
  """Since the bootstrap process attempts to defer all logic to the recipes-py
  repo, we need to be aware if the user is overriding the recipe_engine
  dependency. This looks for and returns the overridden recipe_engine path, if
  any, or None if the user didn't override it."""
  PREFIX = 'recipe_engine='

  p = argparse.ArgumentParser()
  p.add_argument('-O', '--project-override', action='append')
  args, _ = p.parse_known_args(argv)
  for override in args.project_override or ():
    if override.startswith(PREFIX):
      return override[len(PREFIX):]
  return None


def main():
  if '--verbose' in sys.argv:
    logging.getLogger().setLevel(logging.INFO)

  if REPO_ROOT is None or RECIPES_CFG is None:
    logging.error(
      'In order to use this script, please copy it to your repo and '
      'replace the REPO_ROOT and RECIPES_CFG values with approprite paths.')
    sys.exit(1)

  if sys.platform.startswith(('win', 'cygwin')):
    git = 'git.bat'
  else:
    git = 'git'

  # Find the repository and config file to operate on.
  repo_root = os.path.abspath(
      os.path.join(os.path.dirname(__file__), REPO_ROOT))
  recipes_cfg_path = os.path.join(repo_root, RECIPES_CFG)

  engine_url, engine_revision, engine_subpath, recipes_path = parse(
    repo_root, recipes_cfg_path)

  deps_path = os.path.join(recipes_path, '.recipe_deps')
  engine_path = find_engine_override(sys.argv[1:])
  if not engine_path:
    # Ensure that we have the recipe engine cloned.
    engine_root_path = os.path.join(deps_path, 'recipe_engine')
    engine_path = os.path.join(engine_root_path, engine_subpath)
    def ensure_engine():
      if not os.path.exists(deps_path):
        os.makedirs(deps_path)
      if not os.path.exists(engine_root_path):
        _subprocess_check_call([git, 'clone', engine_url, engine_root_path])

      needs_fetch = _subprocess_call(
          [git, 'rev-parse', '--verify', '%s^{commit}' % engine_revision],
          cwd=engine_root_path, stdout=open(os.devnull, 'w'))
      if needs_fetch:
        _subprocess_check_call([git, 'fetch'], cwd=engine_root_path)
      _subprocess_check_call(
          [git, 'checkout', '--quiet', engine_revision], cwd=engine_root_path)

    try:
      ensure_engine()
    except subprocess.CalledProcessError:
      logging.exception('ensure_engine failed')

      # Retry errors.
      time.sleep(random.uniform(2,5))
      ensure_engine()

  args = ['--package', recipes_cfg_path] + sys.argv[1:]
  return _subprocess_call([
      sys.executable, '-u',
      os.path.join(engine_path, 'recipes.py')] + args)

if __name__ == '__main__':
  sys.exit(main())