from __future__ import annotations

from pathlib import Path

import yaml

from app.agents.skills.types import Skill, SkillMetadata, SkillSource


class SkillLoader:
    """SKILL.md 파일 파싱 및 로딩."""

    @staticmethod
    def parse_skill_file(content: str, path: str, source: SkillSource) -> Skill:
        """YAML frontmatter + markdown body를 파싱하여 Skill 객체 반환."""
        frontmatter, instructions = SkillLoader._split_frontmatter(content)
        meta = yaml.safe_load(frontmatter) or {}
        return Skill(
            name=meta.get("name", ""),
            description=meta.get("description", ""),
            path=path,
            source=source,
            instructions=instructions.strip(),
        )

    @staticmethod
    def load_from_path(path: str | Path, source: SkillSource) -> Skill:
        """파일 경로에서 Skill을 로드."""
        p = Path(path)
        content = p.read_text(encoding="utf-8")
        return SkillLoader.parse_skill_file(content, str(p), source)

    @staticmethod
    def extract_metadata(path: str | Path, source: SkillSource) -> SkillMetadata:
        """frontmatter만 파싱하여 경량 메타데이터 반환."""
        p = Path(path)
        content = p.read_text(encoding="utf-8")
        frontmatter, _ = SkillLoader._split_frontmatter(content)
        meta = yaml.safe_load(frontmatter) or {}
        return SkillMetadata(
            name=meta.get("name", ""),
            description=meta.get("description", ""),
            path=str(p),
            source=source,
        )

    @staticmethod
    def _split_frontmatter(content: str) -> tuple[str, str]:
        """--- 마커 사이의 YAML frontmatter와 나머지 body를 분리."""
        stripped = content.strip()
        if not stripped.startswith("---"):
            return "", content

        # 두 번째 --- 찾기
        end_idx = stripped.find("---", 3)
        if end_idx == -1:
            return "", content

        frontmatter = stripped[3:end_idx].strip()
        body = stripped[end_idx + 3 :]
        return frontmatter, body