Small Python script to correct wrong offset values for converted TJAs from TakoTako <=3.2.0

fix_converted_tja_fumenOffsetPos.py

"""
Fix offset values due to bug in older versions of TakoTako (<=3.2.0)
See also: https://github.com/Fluto/TakoTako/issues/16

Bug description:

- TJA songs have an "OFFSET:" value.
- When converting TJAs to fumen, "OFFSET" is automatically included in
  the data of the fumen files themselves.
- However, TakoTako also added the "OFFSET" value to "fumenOffsetPos"
  field inside the "data.json" file for the converted TJA.
- This means that "OFFSET" is accidentally counted twice!! This causes desync.

So, to fix this problem, this script automatically edits all of the "data.json"
files and resets them back to their original values. This removes the desync.
"""

import os
import json

# Make sure to edit to point to the directory with custom songs
CUSTOMSONG_DIR = os.path.join("C:\\", "TaikoTDM", "CustomSongs")

# Step 1. Read in the existing song data
for root, dirs, files in os.walk(CUSTOMSONG_DIR, topdown=True):
    if "data.json" in files:
        json_path = os.path.join(root, "data.json")
        json_dict = json.load(open(json_path, encoding="utf8"))
        old_offset = json_dict['fumenOffsetPos']
        # 1: Offset is below 0 -- Fix by setting to 0. (Offset was modified by TakoTako)
        if old_offset < 0:
            json_dict['fumenOffsetPos'] = 0
            print(f"Old: {old_offset}, New: 0, Song: {root}")
        # 2: Offset is below 2000 -- Fix by setting to 2000
        #    Note: TakoTako adds 2s of silence for songs with small offsets. That's why there
        #          are songs with ~2000ms of offset -- to match the edited audio from TakoTako.
        elif 1000 <= old_offset < 2000:
            json_dict['fumenOffsetPos'] = 2000
            print(f"Old: {old_offset}, New: 2000, Song: {root}")
        # 3. Offset is between 0 and 1000 -- Do nothing. (Offset was not modified by TakoTako.)
        else:
            print(f"Skipping song due to correct fumenOffsetPos '{old_offset}' ({root}).")
            
        with open(json_path, "w", encoding="utf8") as outfile:
            # Get the JSON data to be written, as a string
            str_to_write = json.dumps(json_dict, indent="\t", ensure_ascii=False)
            # Account for the fact that some keys are "key:value" while others are
            # "key: value"
            str_to_write = str_to_write.replace(': ', ':')
            for key in ["songName", "songSubtitle", "songDetail",
                        "text", "font", "jpText", "jpFont",
                        "enText", "enFont", "krText", "krFont"]:
                str_to_write = str_to_write.replace(f'"{key}":', f'"{key}": ')
            # Account for the nonstandard tab indentation used by the existing
            # files
            str_to_write = str_to_write.replace("\t", "\t\t")
            str_to_write = str_to_write.replace("\t\t\t\t", "\t\t\t")
            str_to_write = "\t" + str_to_write[:-1] + "\t}"
            # Write the modified JSON string to the file
            outfile.write(str_to_write)