from __future__ import annotations

from quart import Blueprint, g, redirect, url_for, request
from sqlalchemy import select, func, or_, cast, String, exists
from sqlalchemy.orm import selectinload

from shared.models.order import Order, OrderItem

from shared.infrastructure.http_utils import vary as _vary, current_url_without_page as _current_url_without_page
from shared.infrastructure.cart_identity import current_cart_identity
from bp.order.routes import register as register_order

from .filters.qs import makeqs_factory, decode


def register(url_prefix: str) -> Blueprint:
    bp = Blueprint("orders", __name__, url_prefix=url_prefix)
    bp.register_blueprint(register_order())

    ORDERS_PER_PAGE = 10

    @bp.before_request
    def route():
        g.makeqs_factory = makeqs_factory

    @bp.before_request
    async def _require_identity():
        """Orders require a logged-in user or at least a cart session."""
        ident = current_cart_identity()
        if not ident["user_id"] and not ident["session_id"]:
            return redirect(url_for("auth.login_form"))

    @bp.get("/rows")
    async def orders_rows():
        """Pagination endpoint — returns order rows for page > 1."""
        ident = current_cart_identity()
        if ident["user_id"]:
            owner_clause = Order.user_id == ident["user_id"]
        elif ident["session_id"]:
            owner_clause = Order.session_id == ident["session_id"]
        else:
            return redirect(url_for("auth.login_form"))

        q = decode()
        page, search = q.page, q.search
        if page < 1:
            page = 1

        where_clause = _search_clause(search) if search else None

        count_stmt = select(func.count()).select_from(Order).where(owner_clause)
        if where_clause is not None:
            count_stmt = count_stmt.where(where_clause)

        total_count_result = await g.s.execute(count_stmt)
        total_count = total_count_result.scalar_one() or 0
        total_pages = max(1, (total_count + ORDERS_PER_PAGE - 1) // ORDERS_PER_PAGE)

        if page > total_pages:
            page = total_pages

        offset = (page - 1) * ORDERS_PER_PAGE
        stmt = (
            select(Order)
            .where(owner_clause)
            .order_by(Order.created_at.desc())
            .offset(offset)
            .limit(ORDERS_PER_PAGE)
        )
        if where_clause is not None:
            stmt = stmt.where(where_clause)

        result = await g.s.execute(stmt)
        orders = result.scalars().all()

        from shared.sx.helpers import sx_response, sx_call
        from shared.utils import route_prefix

        pfx = route_prefix()
        order_dicts = []
        for o in orders:
            order_dicts.append({
                "id": o.id,
                "status": o.status or "pending",
                "created_at_formatted": o.created_at.strftime("%-d %b %Y, %H:%M") if o.created_at else "\u2014",
                "description": o.description or "",
                "currency": o.currency or "GBP",
                "total_formatted": f"{o.total_amount or 0:.2f}",
            })

        detail_prefix = pfx + url_for("defpage_order_detail", order_id=0).rsplit("0/", 1)[0]
        qs_fn = makeqs_factory()
        rows_url = pfx + url_for("orders.orders_rows")

        # Build just the rows fragment (not full table) for infinite scroll
        parts = []
        for od in order_dicts:
            parts.append(sx_call("order-row-pair",
                order=od,
                detail_url_prefix=detail_prefix))
        if page < total_pages:
            parts.append(sx_call("infinite-scroll",
                url=rows_url + qs_fn(page=page + 1),
                page=page, total_pages=total_pages,
                id_prefix="orders", colspan=5))
        else:
            parts.append(sx_call("order-end-row"))
        sx_src = "(<> " + " ".join(parts) + ")"

        resp = sx_response(sx_src)
        resp.headers["Hx-Push-Url"] = _current_url_without_page()
        return _vary(resp)

    return bp


def _search_clause(search: str):
    """Build an OR search clause across order fields."""
    term = f"%{search.strip()}%"
    conditions = [
        Order.status.ilike(term),
        Order.currency.ilike(term),
        Order.sumup_checkout_id.ilike(term),
        Order.sumup_status.ilike(term),
        Order.description.ilike(term),
    ]
    conditions.append(
        exists(
            select(1)
            .select_from(OrderItem)
            .where(
                OrderItem.order_id == Order.id,
                or_(
                    OrderItem.product_title.ilike(term),
                    OrderItem.product_slug.ilike(term),
                ),
            )
        )
    )
    try:
        search_id = int(search)
    except (TypeError, ValueError):
        search_id = None
    if search_id is not None:
        conditions.append(Order.id == search_id)
    else:
        conditions.append(cast(Order.id, String).ilike(term))
    return or_(*conditions)