"""Save processed knowledge items as Obsidian markdown notes."""

import os
import re
from datetime import datetime
from pathlib import Path


def _slugify(text: str, max_len: int = 50) -> str:
    """Convert text to a filesystem-safe slug."""
    text = re.sub(r"[^\w\s-]", "", text, flags=re.UNICODE)
    text = re.sub(r"[\s_]+", "-", text).strip("-")
    return text[:max_len].lower()


def save_note(
    content_type: str,
    title: str,
    summary: str,
    body: str,
    tags: list[str],
    source_url: str = "",
    author: str = "",
    date: str = "",
) -> Path:
    """Save a processed knowledge item as an Obsidian markdown file.

    Args:
        content_type: One of 'youtube', 'url', 'text'.
        title: The note title.
        summary: LLM-generated summary.
        body: Full content text.
        tags: List of topic tags.
        source_url: Original URL (empty for plain text).
        author: Author name (may be empty).
        date: Publication date in ISO 8601 format (may be empty).

    Returns:
        Path of the created markdown file.
    """
    vault = os.environ.get("OBSIDIAN_VAULT", "/Users/joungmin/Documents/Obsidian Vault")
    today = datetime.now().strftime("%Y-%m-%d")
    now_str = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    slug = _slugify(title) or "untitled"

    # Determine subfolder by content type
    subfolder_map = {
        "youtube": "20 Sources/YouTube",
        "url": "20 Sources/Web",
        "text": "20 Sources/Notes",
    }
    subfolder = subfolder_map.get(content_type, "20 Sources/Notes")
    note_dir = Path(vault) / subfolder
    note_dir.mkdir(parents=True, exist_ok=True)

    filename = f"{today}-{slug}.md"
    note_path = note_dir / filename

    # Build YAML frontmatter tags
    tags_yaml = ", ".join(tags) if tags else ""

    content = f"""---
title: {title}
source_type: {content_type}
url: {source_url}
author: {author}
date: {date}
tags: [{tags_yaml}]
created: {today}
---

# {title}

## 요약
{summary}

## 원문
{body}

---
*Source: {source_url}*
*Saved: {now_str}*
"""

    note_path.write_text(content, encoding="utf-8")
    return note_path