Convert a python camelCase code base to snake_case

convert_python_files_from_camelCase_to_snake_case.py

"""
This is currently highly experimental!!
Please make a backup before testing it..
"""

from __future__ import print_function

import os
import re
import sys
import json
import datetime


FUNCTION_REGEX = re.compile(r"( |\t)*def (?P<funcname>[_A-Za-z-0-9]*)")

def find_all_python_files(target_dir):
    files_list = []
    for root, folder, files in os.walk(target_dir):
        for file in files:
            if file.endswith(".py"):
                files_list.append(os.path.join(root, file))
    return files_list

def find_words_in_function_name(value):

    current_word = []
    words = []

    for c in value:

        # We have reached a new word
        if c == "_" or c.upper() == c:
            current_word = "".join(current_word)
            if current_word:
                words.append(current_word)
            if c != "_":
                current_word = [c]
            else:
                current_word = []
        else:
            if c and c != "_":
                current_word.append(c)

    current_word = "".join(current_word)
    words.append(current_word)

    return words

def get_all_functions(file_path, functions_map):

    if not os.access(file_path, os.R_OK):
        sys.stderr.write("Cannot read file %s\n" % file_path)
        return

    with open(file_path, "r") as f:
        file_content = f.readlines()
        for line in file_content:

            matches = FUNCTION_REGEX.match(line.lstrip())
            if not matches:
                continue

            function_name = matches.groupdict("funcname")["funcname"]

            all_lower = function_name.lower()

            if function_name == all_lower:
                continue

            words = find_words_in_function_name(function_name)

            function_name = "%s(" % function_name
            functions_map[function_name] = ("_".join(words)).lower() + "("

def replace_functions_in_file(file_path, functions_map, dry_run=True):

    current_file_content = []

    # Search...
    with open(file_path, "r") as f:
        file_content = f.readlines()

        fix_all_header = False

        for line in file_content:
            for old_name, new_name in functions_map.iteritems():

                # Deal with the top level __all__ "mask" that is used to
                # only make some functions public
                if "__all__" in line:
                    fix_all_header = True

                # end of the __all__ (which can be potentially multiline)
                if "]" in line and fix_all_header:
                    fix_all_header = False

                if fix_all_header:
                    old_name_without_parenthesis = old_name.replace("(", "")
                    new_name_without_parenthesis = new_name.replace("(", "")

                    if old_name_without_parenthesis in line:
                        func_regex_pattern = r"\b%s\b" % old_name_without_parenthesis
                        for item in re.findall(func_regex_pattern, line):
                            line = line.replace(
                                item,
                                new_name_without_parenthesis
                            )

                # Body of module.. nothing to worry about in theory
                elif old_name in line:
                    line = line.replace(old_name, new_name)

            current_file_content.append(line)

    # ...and replace
    if not dry_run:
        with open(file_path, "w") as f:
            f.write("".join(current_file_content))

def generate_report(functions_map):
    timestamp = datetime.datetime.now().strftime("%Y-%m-%d-%H-%M-%s")
    report_file_name = "camelCase_to_snakeCase_%s.json" % timestamp
    report_file_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), report_file_name)

    with open(report_file_path, "w") as f:
        json.dump(functions_map, f, indent=4)

def main():

    functions_map = {}
    dry_run = False

    # target_file = "/Users/vvzen/Documents/code/pipeline/framestore/commsfcurve/commsfcurve/math/easing/filters.py"
    # get_all_functions(target_file, functions_map)
    # replace_functions_in_file(target_file, functions_map, dry_run=dry_run)

    # target_file = "/Users/vvzen/Documents/code/pipeline/framestore/commsfcurve/commsfcurve/FCurve.py"
    # get_all_functions(target_file, functions_map)
    # replace_functions_in_file(target_file, functions_map, dry_run=dry_run)

    target_dir = "/Users/vvzen/Documents/code/pipeline/framestore/commsfcurve"
    python_files = find_all_python_files(target_dir)

    # 1. Build a list of all the functions
    for f in python_files:
        get_all_functions(f, functions_map)

    # 2. Convert to snake_case
    for f in python_files:
        replace_functions_in_file(f, functions_map, dry_run=dry_run)

    generate_report(functions_map)

if __name__ == '__main__':
    main()