from __future__ import annotations

from pathlib import Path


class CommentFlagMigrationService:
    def migrate(self, session_dir: Path) -> dict[str, int]:
        migrated_split_flags = 0
        legacy_untracked_full = 0
        if not session_dir.exists():
            return {"migrated_split_flags": 0, "legacy_untracked_full": 0}

        for folder in sorted(p for p in session_dir.iterdir() if p.is_dir()):
            comment_done = folder / "comment_done.flag"
            split_done = folder / "comment_split_done.flag"
            full_done = folder / "comment_full_done.flag"
            if not comment_done.exists():
                continue
            if not split_done.exists():
                split_done.touch()
                migrated_split_flags += 1
            if not full_done.exists():
                legacy_untracked_full += 1
        return {
            "migrated_split_flags": migrated_split_flags,
            "legacy_untracked_full": legacy_untracked_full,
        }