#!/usr/bin/env python3

import argparse
import os
import re

parser = argparse.ArgumentParser(description="Renames the starts of lines in every file")

parser.add_argument("old", help="old start of line", type=str)
parser.add_argument("new", help="new start of line", type=str)

args = parser.parse_args()

lineCount = 0
fileCount = 0
def editfile(f, old, new):
    global lineCount, fileCount
    contents = f.readlines()
    newContents = ""
    f.seek(0)
    edited = False
    for line in contents:
        if line.startswith(old):
            edited = True
            lineCount += 1
            line = new + line[len(old):]

        newContents += line
    if edited:
        fileCount += 1
    f.write(newContents)

    f.truncate()

for dirpath, dirname, filenames in os.walk("."):
    for filename in filenames:
        if filename.endswith("CMakeLists.txt"):
            with open(dirpath +"/" + filename, "r+") as f:
                editfile(f, args.old, args.new)
print("Edited " + str(lineCount) + " lines in " + str(fileCount) + " files.")