"""Cart app data endpoints.

Exposes read-only JSON queries at ``/internal/data/<query_name>`` for
cross-app callers via the internal data client.
"""
from __future__ import annotations

from quart import Blueprint, g, jsonify, request

from shared.infrastructure.data_client import DATA_HEADER
from shared.contracts.dtos import dto_to_dict
from shared.services.registry import services


def register() -> Blueprint:
    bp = Blueprint("data", __name__, url_prefix="/internal/data")

    @bp.before_request
    async def _require_data_header():
        if not request.headers.get(DATA_HEADER):
            return jsonify({"error": "forbidden"}), 403
        from shared.infrastructure.internal_auth import validate_internal_request
        if not validate_internal_request():
            return jsonify({"error": "forbidden"}), 403

    _handlers: dict[str, object] = {}

    @bp.get("/<query_name>")
    async def handle_query(query_name: str):
        handler = _handlers.get(query_name)
        if handler is None:
            return jsonify({"error": "unknown query"}), 404
        result = await handler()
        return jsonify(result)

    # --- cart-summary ---
    async def _cart_summary():
        user_id = request.args.get("user_id", type=int)
        session_id = request.args.get("session_id")
        page_slug = request.args.get("page_slug")
        summary = await services.cart.cart_summary(
            g.s, user_id=user_id, session_id=session_id, page_slug=page_slug,
        )
        return dto_to_dict(summary)

    _handlers["cart-summary"] = _cart_summary

    # --- cart-items (product slugs + quantities for template rendering) ---
    async def _cart_items():
        from sqlalchemy import select
        from shared.models.market import CartItem

        user_id = request.args.get("user_id", type=int)
        session_id = request.args.get("session_id")

        filters = [CartItem.deleted_at.is_(None)]
        if user_id is not None:
            filters.append(CartItem.user_id == user_id)
        elif session_id is not None:
            filters.append(CartItem.session_id == session_id)
        else:
            return []

        result = await g.s.execute(
            select(CartItem).where(*filters)
        )
        items = result.scalars().all()
        return [
            {
                "product_id": item.product_id,
                "product_slug": item.product_slug,
                "quantity": item.quantity,
            }
            for item in items
        ]

    _handlers["cart-items"] = _cart_items

    return bp
