#!/usr/bin/env python
# Copyright 2017 The Dart project authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# Usage: tools/dart/create_updated_flutter_deps.py [-d dart/DEPS] [-f flutter/DEPS]
#
# This script parses existing flutter DEPS file, identifies all 'dart_' prefixed
# dependencies, looks up revision from dart DEPS file, updates those dependencies
# and rewrites flutter DEPS file.

import argparse
import os
import sys

DART_SCRIPT_DIR = os.path.dirname(sys.argv[0])
DART_ROOT = os.path.realpath(os.path.join(DART_SCRIPT_DIR, '../../third_party/dart'))
FLUTTER_ROOT = os.path.realpath(os.path.join(DART_SCRIPT_DIR, '../../flutter'))

class VarImpl(object):
  def __init__(self, local_scope):
    self._local_scope = local_scope

  def Lookup(self, var_name):
    """Implements the Var syntax."""
    if var_name in self._local_scope.get("vars", {}):
      return self._local_scope["vars"][var_name]
    if var_name == 'host_os':
      return 'linux' # assume some default value
    if var_name == 'host_cpu':
      return 'x64' # assume some default value
    raise Exception("Var is not defined: %s" % var_name)


def ParseDepsFile(deps_file):
  local_scope = {}
  var = VarImpl(local_scope)
  global_scope = {
    'Var': var.Lookup,
    'deps_os': {},
  }
  # Read the content.
  with open(deps_file, 'r') as fp:
    deps_content = fp.read()

  # Eval the content.
  exec(deps_content, global_scope, local_scope)

  return local_scope.get('vars', {})

def ParseArgs(args):
  args = args[1:]
  parser = argparse.ArgumentParser(
      description='A script to generate updated dart dependencies for flutter DEPS.')
  parser.add_argument('--dart_deps', '-d',
      type=str,
      help='Dart DEPS file.',
      default=os.path.join(DART_ROOT, 'DEPS'))
  parser.add_argument('--flutter_deps', '-f',
      type=str,
      help='Flutter DEPS file.',
      default=os.path.join(FLUTTER_ROOT, 'DEPS'))
  return parser.parse_args(args)

def Main(argv):
  args = ParseArgs(argv)
  new_deps = ParseDepsFile(args.dart_deps)
  old_deps = ParseDepsFile(args.flutter_deps)
  updated_deps = {}
  missing_deps = []

  # Collect updated dependencies
  for (k,v) in sorted(old_deps.iteritems()):
    if k not in ('dart_revision', 'dart_git') and k.startswith('dart_'):
      v = '???'
      dart_key = k[len('dart_'):]
      if not new_deps.has_key(dart_key):
        missing_deps.append(k)
      updated_revision = new_deps[dart_key].lstrip('@') if new_deps.has_key(dart_key) else v
      updated_deps[k] = updated_revision

  # Write updated DEPS file to a side
  updatedfilename = args.flutter_deps + ".new"
  updatedfile = open(updatedfilename, "w")
  file = open(args.flutter_deps)
  lines = file.readlines()
  i = 0
  while i < len(lines):
    updatedfile.write(lines[i])
    if lines[i].startswith("  'dart_revision':"):
      i = i + 2
      updatedfile.writelines([
        '\n',
        '  # WARNING: DO NOT EDIT MANUALLY\n',
        '  # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py\n'])
      while i < len(lines) and len(lines[i].strip()) > 0:
        i = i + 1
      for (k, v) in sorted(updated_deps.iteritems()):
        updatedfile.write("  '%s': '%s',\n" % (k, v))
      updatedfile.write('\n')
    i = i + 1

  if len(missing_deps) > 0:
    print("Error: flutter dependencies %s removed from dart" % missing_deps)
    print("Intermediate results are in %s" % updatedfilename)
    return 1

  # Rename updated DEPS file into a new DEPS file
  os.remove(args.flutter_deps)
  os.rename(updatedfilename, args.flutter_deps)

  return 0

if __name__ == '__main__':
  sys.exit(Main(sys.argv))