# -*- coding: utf-8 -*-
"""Skill metadata parsing helpers for SKILL.md files."""

from dataclasses import dataclass, field
from pathlib import Path
from typing import List

import yaml


@dataclass(frozen=True)
class SkillMetadata:
    """Parsed metadata for a skill package."""

    skill_name: str
    path: Path
    source: str
    name: str
    description: str
    version: str = ""
    tools: List[str] = field(default_factory=list)


def parse_skill_metadata(skill_dir: Path, source: str) -> SkillMetadata:
    """Parse SKILL.md frontmatter with a forgiving schema."""
    skill_name = skill_dir.name
    skill_file = skill_dir / "SKILL.md"
    if not skill_file.exists():
        return SkillMetadata(
            skill_name=skill_name,
            path=skill_dir,
            source=source,
            name=skill_name,
            description="",
        )

    raw = skill_file.read_text(encoding="utf-8").strip()
    frontmatter = {}
    body = raw
    if raw.startswith("---"):
        parts = raw.split("---", 2)
        if len(parts) >= 3:
            try:
                frontmatter = yaml.safe_load(parts[1].strip()) or {}
            except yaml.YAMLError:
                frontmatter = {}
            body = parts[2].strip()
    if not isinstance(frontmatter, dict):
        frontmatter = {}

    description = str(frontmatter.get("description") or "").strip()
    if not description and body:
        description = body.splitlines()[0].strip().lstrip("#").strip()

    return SkillMetadata(
        skill_name=skill_name,
        path=skill_dir,
        source=source,
        name=str(frontmatter.get("name") or skill_name).strip() or skill_name,
        description=description,
        version=str(frontmatter.get("version") or "").strip(),
        tools=_string_list(frontmatter.get("tools")),
    )


def _string_list(value) -> List[str]:
    if isinstance(value, str):
        item = value.strip()
        return [item] if item else []
    if not isinstance(value, list):
        return []
    seen: List[str] = []
    for item in value:
        if not isinstance(item, str):
            continue
        normalized = item.strip()
        if normalized and normalized not in seen:
            seen.append(normalized)
    return seen