from __future__ import annotations

import os
from dataclasses import dataclass
from pathlib import Path
from typing import Iterator


@dataclass(frozen=True)
class VaultPaths:
    root: str
    notes: str
    attachments: str
    kb: str


class Vault:
    def __init__(self, root_path: str):
        root = Path(root_path).expanduser().resolve()
        object.__setattr__(
            self,
            "paths",
            VaultPaths(
                root=str(root),
                notes=str(root / "notes"),
                attachments=str(root / "attachments"),
                kb=str(root / ".kb"),
            ),
        )

    def ensure_structure(self) -> None:
        Path(self.paths.notes).mkdir(parents=True, exist_ok=True)
        Path(self.paths.attachments).mkdir(parents=True, exist_ok=True)
        Path(self.paths.kb).mkdir(parents=True, exist_ok=True)

    def abspath(self, rel_path: str) -> str:
        # If rel_path is absolute, Path(root) / rel_path will return rel_path as-is.
        return str((Path(self.paths.root) / rel_path).resolve())

    def relpath(self, abs_path: str) -> str:
        return str(Path(abs_path).resolve().relative_to(Path(self.paths.root).resolve()))

    def iter_markdown_files(self) -> Iterator[str]:
        """
        Yield absolute paths to .md files under <vault>/notes recursively.
        - Allows the vault root to be hidden or not.
        - Skips hidden subdirectories within notes/ (names starting with '.').
        - Skips hidden files (names starting with '.').
        """
        notes_dir = Path(self.paths.notes)
        if not notes_dir.exists():
            return iter(())

        # Walk manually to filter hidden dirs/files
        for dirpath, dirnames, filenames in os.walk(notes_dir):
            # Remove hidden subdirectories in-place (prevents os.walk from entering them)
            dirnames[:] = [d for d in dirnames if not d.startswith(".")]
            for fname in filenames:
                if fname.startswith("."):
                    continue
                if not fname.endswith(".md"):
                    continue
                yield str(Path(dirpath, fname).resolve())