"""Canonical skill registry and adapter sync helpers."""

from __future__ import annotations

import shutil
from dataclasses import dataclass
from pathlib import Path


REPO_ROOT = Path(__file__).resolve().parents[2]
CANONICAL_SKILLS_DIR = REPO_ROOT / ".agents" / "skills"
PROJECT_SKILLS_DIR = REPO_ROOT / "skills"
REQUIRED_SKILLS = {
    "search-strategy",
    "search-gateway",
    "source-quality",
    "length-budget",
    "evidence-table",
    "citation-manager",
    "mckinsey-method",
}


@dataclass(frozen=True)
class SkillInfo:
    name: str
    path: Path


class SkillRegistry:
    """Reads skills from the canonical cross-adapter registry."""

    def __init__(self, canonical_dir: Path | None = None) -> None:
        self.canonical_dir = canonical_dir or CANONICAL_SKILLS_DIR

    def roots(self) -> list[Path]:
        roots = [self.canonical_dir]
        if self.canonical_dir == CANONICAL_SKILLS_DIR and PROJECT_SKILLS_DIR.exists():
            roots.append(PROJECT_SKILLS_DIR)
        return roots

    def list(self) -> list[SkillInfo]:
        seen: set[str] = set()
        out: list[SkillInfo] = []
        for root in self.roots():
            if not root.exists():
                continue
            for path in sorted(root.glob("*/SKILL.md")):
                name = path.parent.name
                if name in seen:
                    continue
                seen.add(name)
                out.append(SkillInfo(name=name, path=path))
        return out

    def list_names(self) -> list[str]:
        return [item.name for item in self.list()]

    def read(self, name: str) -> str:
        for root in self.roots():
            path = root / name / "SKILL.md"
            if path.exists():
                return path.read_text(encoding="utf-8")
        raise FileNotFoundError(f"skill not found: {name}")

    def validate(self, required: set[str] | None = None) -> dict[str, object]:
        names = set(self.list_names())
        required_names = required or REQUIRED_SKILLS
        missing = sorted(required_names - names)
        malformed: list[str] = []
        for item in self.list():
            text = item.path.read_text(encoding="utf-8")
            if "name:" not in text[:300]:
                malformed.append(item.name)
        return {
            "ok": not missing and not malformed,
            "canonical_dir": str(self.canonical_dir),
            "count": len(names),
            "missing": missing,
            "malformed": malformed,
        }

    def sync_to(self, targets: list[Path], *, force: bool = True) -> int:
        """Copy canonical skills into adapter skill directories.

        Returns the number of skill directories copied across all targets.
        """
        copied = 0
        for target in targets:
            if target.resolve() == self.canonical_dir.resolve():
                continue
            target.mkdir(parents=True, exist_ok=True)
            for item in self.list():
                dst = target / item.name
                if dst.exists() and force:
                    shutil.rmtree(dst)
                if not dst.exists():
                    shutil.copytree(item.path.parent, dst)
                    copied += 1
        return copied


def default_adapter_skill_dirs() -> list[Path]:
    return [
        REPO_ROOT / ".opencode" / "skills",
        REPO_ROOT / ".agents" / "skills",
    ]