#!/usr/bin/env python

# This pre-processor parses provided objects' c files for
# MP_REGISTER_MODULE(module_name, obj_module, enabled_define)
# These are used to generate a header with the required entries for
# "mp_rom_map_elem_t mp_builtin_module_table[]" in py/objmodule.c

from __future__ import print_function

import re
import io
import os
import argparse


pattern = re.compile(r"[\n;]\s*MP_REGISTER_MODULE\((.*?),\s*(.*?),\s*(.*?)\);", flags=re.DOTALL)


def find_c_file(obj_file, vpath):
 """Search vpaths for the c file that matches the provided object_file.

 :param str obj_file: object file to find the matching c file for
 :param List[str] vpath: List of base paths, similar to gcc vpath
 :return: str path to c file or None
 """
 c_file = None
 relative_c_file = os.path.splitext(obj_file)[0] + ".c"
 relative_c_file = relative_c_file.lstrip("/\\")
 for p in vpath:
 possible_c_file = os.path.join(p, relative_c_file)
 if os.path.exists(possible_c_file):
 c_file = possible_c_file
 break

 return c_file


def find_module_registrations(c_file):
 """Find any MP_REGISTER_MODULE definitions in the provided c file.

 :param str c_file: path to c file to check
 :return: List[(module_name, obj_module, enabled_define)]
 """
 global pattern

 if c_file is None:
 # No c file to match the object file, skip
 return set()

 with io.open(c_file, encoding="utf-8") as c_file_obj:
 return set(re.findall(pattern, c_file_obj.read()))


def generate_module_table_header(modules):
 """Generate header with module table entries for builtin modules.

 :param List[(module_name, obj_module, enabled_define)] modules: module defs
 :return: None
 """

 # Print header file for all external modules.
 mod_defs = []
 print("// Automatically generated by makemoduledefs.py.\n")
 for module_name, obj_module, enabled_define in modules:
 mod_def = "MODULE_DEF_{}".format(module_name.upper())
 mod_defs.append(mod_def)
 print(
 (
 "#if ({enabled_define})\n"
 " extern const struct _mp_obj_module_t {obj_module};\n"
 " #define {mod_def} {{ MP_ROM_QSTR({module_name}), MP_ROM_PTR(&{obj_module}) }},\n"
 "#else\n"
 " #define {mod_def}\n"
 "#endif\n"
 ).format(
 module_name=module_name,
 obj_module=obj_module,
 enabled_define=enabled_define,
 mod_def=mod_def,
 )
 )

 print("\n#define MICROPY_REGISTERED_MODULES \\")

 for mod_def in mod_defs:
 print(" {mod_def} \\".format(mod_def=mod_def))

 print("// MICROPY_REGISTERED_MODULES")


def main():
 parser = argparse.ArgumentParser()
 parser.add_argument(
 "--vpath", default=".", help="comma separated list of folders to search for c files in"
 )
 parser.add_argument("files", nargs="*", help="list of c files to search")
 args = parser.parse_args()

 vpath = [p.strip() for p in args.vpath.split(",")]

 modules = set()
 for obj_file in args.files:
 c_file = find_c_file(obj_file, vpath)
 modules |= find_module_registrations(c_file)

 generate_module_table_header(sorted(modules))


if __name__ == "__main__":
 main()