import os
import re
from pathlib import Path

def apply_patch(patch_file, target_folder):
    with open(patch_file, 'r') as f:
        patch_content = f.read()

    # Split the patch into individual file diffs
    file_diffs = re.split(r'diff --git ', patch_content)[1:]

    for diff in file_diffs:
        # Extract the file path
        file_path = diff.split('\n')[0].split()[-1][2:]
        target_file = Path(target_folder) / file_path

        if not target_file.exists():
            print(f"Warning: Target file {target_file} does not exist. Skipping.")
            continue

        # Read the original file content
        with open(target_file, 'r') as f:
            original_content = f.readlines()

        # Parse the diff hunks
        hunks = re.findall(r'@@ -(\d+),(\d+) \+(\d+),(\d+) @@([\s\S]+?)(?=@@|\Z)', diff)

        # Apply the changes
        new_content = original_content.copy()
        offset = 0
        for hunk in hunks:
            start = int(hunk[2]) - 1 + offset
            removed = int(hunk[1])
            added = int(hunk[3])
            changes = hunk[4].strip().split('\n')

            # Remove lines
            del new_content[start:start + removed]

            # Add new lines
            for change in changes:
                if change.startswith('+'):
                    new_content.insert(start, change[1:] + '\n')
                    start += 1

            offset += added - removed

        # Write the modified content back to the file
        with open(target_file, 'w') as f:
            f.writelines(new_content)

        print(f"Applied changes to {target_file}")

# Usage
patch_file = '/media/tom/1T-Disk/kernel/patch-5.10.209-rt101.patch'
target_folder = '/media/tom/1T-Disk/linux-5.10.209(test)'
apply_patch(patch_file, target_folder)