#!/usr/bin/python3

# Usage: gen_crosstool <base> <cortex_m4f> <output>
# Example: bazel run //tools/cpp:gen_crosstool $(readlink -f tools/cpp/static_crosstool.pb) $(readlink -f tools/cpp/cortex_m4f_crosstool.pb) $(readlink -f tools/cpp/CROSSTOOL)

import sys

from third_party.bazel.protos import crosstool_config_pb2
from google.protobuf import text_format
from google.protobuf.descriptor import FieldDescriptor

def process_string(string, substitutions):
  for a, b in substitutions.items():
    string = string.replace(a, b)
  return string

def rename_message_contents(proto, substitutions):
  for descriptor, value in proto.ListFields():
    if descriptor.type == FieldDescriptor.TYPE_STRING:
      if descriptor.label == FieldDescriptor.LABEL_REPEATED:
        new_value = []
        for string in value:
          new_value.append(process_string(string, substitutions))
        value[:] = new_value
      else:
        setattr(proto, descriptor.name, process_string(value, substitutions))
    if descriptor.type == FieldDescriptor.TYPE_MESSAGE:
      if descriptor.label == FieldDescriptor.LABEL_REPEATED:
        for sub_proto in value:
          rename_message_contents(sub_proto, substitutions)
      else:
        rename_message_contents(value, substitutions)

def add_m4f_toolchain(new_toolchain, m4f_proto, substitutions):
  new_toolchain.CopyFrom(m4f_proto.toolchain[0])
  rename_message_contents(new_toolchain, substitutions)

def main(args):
  crosstool_proto = crosstool_config_pb2.CrosstoolRelease()
  with open(args[0], 'r') as f:
    text_format.Merge(f.read(), crosstool_proto)

  m4f_proto = crosstool_config_pb2.CrosstoolRelease()
  with open(args[1], 'r') as f:
    text_format.Merge(f.read(), m4f_proto)
  add_m4f_toolchain(crosstool_proto.toolchain.add(), m4f_proto, {
      '%NAME%': 'cortex-m4f',
      '%CPU%': '__MK64FX512__',
      '%F_CPU%': '120000000',
      '%LINKER_SCRIPT%': 'motors/core/kinetis_512_256.ld',
      })
  # TODO(Brian): The parts we actually use have 1M of FLASH. Do we want to take
  # advantage, or maintain compatibility with alternative parts that use some
  # of it for EEPROM/FlexMem/etc?
  add_m4f_toolchain(crosstool_proto.toolchain.add(), m4f_proto, {
      '%NAME%': 'cortex-m4f-k22',
      '%CPU%': '__MK22FX512__',
      '%F_CPU%': '120000000',
      '%LINKER_SCRIPT%': 'motors/core/kinetis_512_128.ld',
      })

  with open(args[2], 'w') as f:
    f.write('# GENERATED FILE. DO NOT EDIT\n')
    f.write('# Generated by tools/cpp/gen_crosstool.py\n')
    f.write(text_format.MessageToString(crosstool_proto))

if __name__ == '__main__':
  sys.exit(main(sys.argv[1:]))