Merge branch no ff mock in Python

class MergeResult:
    def __init__(self, base, branch):
        self.base = base
        self.branch = branch
        self.commit_log = []
        self.merged = False

    def simulate_merge(self):
        """Simulate a 'no-ff' merge by creating a new commit that references both branches."""
        if self.base == self.branch:
            self.commit_log.append(f"No-op: branches already identical")
            self.merged = True
            return self.commit_log[0]

        merge_commit = f"Merge commit: HEAD@{self.base} <- {self.branch}"
        self.commit_log.append(f"Creating {merge_commit}")
        self.commit_log.append("No fast-forward performed (--no-ff)")
        self.commit_log.append(f"New commit hash: {hash(self.base + self.branch) % 10000:04d}")
        self.commit_log.append("Base branch updated to merge commit")
        self.merged = True
        return self.commit_log[-1]

    def show_log(self):
        """Return the full commit history message."""
        if not self.commit_log:
            return "No merge performed yet."
        return "\n".join(self.commit_log)


if __name__ == "__main__":
    merge = MergeResult(base="main@sha1234", branch="feature@sha5678")
    merge.simulate_merge()
    print(merge.show_log())