#!/usr/bin/env python3

import sys


def should_include_hunk(hunk_text: str, search: str, replace: str) -> bool:
    return True


def main() -> None:
    if len(sys.argv) != 3:
        raise SystemExit("Usage: mechanicaldiff <search> <replace>")

    search = sys.argv[1]
    replace = sys.argv[2]

    lines = sys.stdin.read().splitlines(keepends=True)
    preamble_lines = []
    sections = []
    current = None

    for line in lines:
        if line.startswith("diff --git "):
            if current is not None:
                sections.append(current)
            current = {"header": [line], "hunks": []}
            continue

        if current is None:
            preamble_lines.append(line)
            continue

        if line.startswith("@@ "):
            current["hunks"].append([line])
        else:
            if current["hunks"]:
                current["hunks"][-1].append(line)
            else:
                current["header"].append(line)

    if current is not None:
        sections.append(current)

    output_lines = []
    output_lines.extend(preamble_lines)

    for section in sections:
        if not section["hunks"]:
            output_lines.extend(section["header"])
            continue

        kept_hunks = []
        for hunk_lines in section["hunks"]:
            hunk_text = "".join(hunk_lines)
            if should_include_hunk(hunk_text, search, replace):
                kept_hunks.append(hunk_lines)

        if not kept_hunks:
            continue

        output_lines.extend(section["header"])
        for hunk_lines in kept_hunks:
            output_lines.extend(hunk_lines)

    sys.stdout.write("".join(output_lines))


if __name__ == "__main__":
    main()