import re
from pathlib import Path

from fastapi import APIRouter, HTTPException
from pydantic import BaseModel

POLICY_DIR = Path(__file__).parent.parent.parent / "policies"
_VALID_NAME = re.compile(r"^[a-z0-9][a-z0-9-]{0,63}$")

router = APIRouter(prefix="/policy", tags=["policy"])


class PolicyRead(BaseModel):
    name: str
    content: str


class PolicyUpdate(BaseModel):
    content: str


def _policy_path(name: str) -> Path:
    if not _VALID_NAME.match(name):
        raise HTTPException(status_code=400, detail="Invalid policy name")
    path = POLICY_DIR / f"{name}.md"
    if not path.exists():
        raise HTTPException(status_code=404, detail=f"Policy '{name}' not found")
    return path


@router.get("/{name}", response_model=PolicyRead)
def get_policy(name: str) -> PolicyRead:
    path = _policy_path(name)
    return PolicyRead(name=name, content=path.read_text())


@router.put("/{name}", response_model=PolicyRead)
def update_policy(name: str, body: PolicyUpdate) -> PolicyRead:
    path = _policy_path(name)
    path.write_text(body.content)
    return PolicyRead(name=name, content=body.content)