from __future__ import annotations

import os
from dataclasses import dataclass
from typing import Iterable


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


class Vault:
    def __init__(self, root_path: str):
        if not root_path:
            raise ValueError("Vault root path must be provided")
        self.root_path = os.path.abspath(root_path)
        self.paths = VaultPaths(
            root=self.root_path,
            notes=os.path.join(self.root_path, "notes"),
            attachments=os.path.join(self.root_path, "attachments"),
            kb=os.path.join(self.root_path, ".kb"),
        )

    def ensure_structure(self) -> None:
        os.makedirs(self.paths.root, exist_ok=True)
        os.makedirs(self.paths.notes, exist_ok=True)
        os.makedirs(self.paths.attachments, exist_ok=True)
        os.makedirs(self.paths.kb, exist_ok=True)

    def relpath(self, abs_path: str) -> str:
        return os.path.relpath(abs_path, self.paths.root)

    def abspath(self, rel_path: str) -> str:
        return os.path.join(self.paths.root, rel_path)

    def iter_markdown_files(self) -> Iterable[str]:
        """Yield absolute file paths for all .md files under notes/ recursively."""
        for dirpath, _, filenames in os.walk(self.paths.notes):
            for fn in filenames:
                if fn.lower().endswith(".md"):
                    yield os.path.join(dirpath, fn)