from flask import Blueprint, Response, redirect, request
from sqlalchemy import select

from l4d2web.auth import require_admin
from l4d2web.db import session_scope
from l4d2web.models import BlueprintOverlay, Overlay
from l4d2web.services.security import validate_overlay_ref


bp = Blueprint("overlay", __name__)


@bp.post("/overlays")
@require_admin
def create_overlay() -> Response:
    name = request.form.get("name", "").strip()
    raw_path = request.form.get("path", "")
    if not name or not raw_path:
        return Response("missing fields", status=400)

    try:
        overlay_ref = validate_overlay_ref(raw_path)
    except ValueError as exc:
        return Response(str(exc), status=400)

    with session_scope() as db:
        existing = db.scalar(select(Overlay).where(Overlay.name == name))
        if existing is not None:
            return Response("overlay already exists", status=409)
        db.add(Overlay(name=name, path=overlay_ref))

    return redirect("/overlays")


@bp.post("/overlays/<int:overlay_id>")
@require_admin
def update_overlay(overlay_id: int) -> Response:
    name = request.form.get("name", "").strip()
    raw_path = request.form.get("path", "")
    if not name or not raw_path:
        return Response("missing fields", status=400)

    try:
        overlay_ref = validate_overlay_ref(raw_path)
    except ValueError as exc:
        return Response(str(exc), status=400)

    with session_scope() as db:
        overlay = db.scalar(select(Overlay).where(Overlay.id == overlay_id))
        if overlay is None:
            return Response(status=404)
        duplicate = db.scalar(select(Overlay).where(Overlay.name == name, Overlay.id != overlay_id))
        if duplicate is not None:
            return Response("overlay already exists", status=409)
        overlay.name = name
        overlay.path = overlay_ref

    return redirect("/overlays")


@bp.post("/overlays/<int:overlay_id>/delete")
@require_admin
def delete_overlay(overlay_id: int) -> Response:
    with session_scope() as db:
        overlay = db.scalar(select(Overlay).where(Overlay.id == overlay_id))
        if overlay is None:
            return Response(status=404)
        in_use = db.scalar(select(BlueprintOverlay).where(BlueprintOverlay.overlay_id == overlay_id))
        if in_use is not None:
            return Response("overlay is in use", status=409)
        db.delete(overlay)
    return redirect("/overlays")