# merge_diff_with_comments.py
# Usage: python merge_diff_with_comments.py diff.txt merged_left.txt

import sys

def merge_diff(diff_file, out_file):
    output_lines = []
    with open(diff_file, "r", encoding="utf-8") as f:
        for line in f:
            if line.startswith(">"):
                # Take the right file's version, strip "> " and add comment
                updated_line = line[2:].rstrip("\n") + " //Pratham : updated\n"
                output_lines.append(updated_line)
            elif line.startswith("<"):
                # Skip the left side's outdated version
                continue
            elif line.startswith("|"):
                # Skip the diff separator
                continue
            else:
                # Common line, keep as-is
                output_lines.append(line)

    with open(out_file, "w", encoding="utf-8") as out:
        out.writelines(output_lines)

if __name__ == "__main__":
    if len(sys.argv) != 3:
        print("Usage: python merge_diff_with_comments.py diff.txt merged_left.txt")
    else:
        merge_diff(sys.argv[1], sys.argv[2])
        print(f"Merged file with comments written to {sys.argv[2]}")