"""
app/tenant/gift_cards/routes.py
Gift card issuance, management, and balance enquiry.
"""
import logging
import secrets
import string
from datetime import datetime, timezone
from flask import Blueprint, render_template, redirect, url_for, flash, request, g
from flask_login import login_required
from app.extensions import db
from app.models.salon import GiftCard, Customer
from app.decorators import require_role, demo_readonly
from app.tenant.utils import log_tenant_action

logger = logging.getLogger(__name__)
gift_cards_bp = Blueprint("gift_cards", __name__, url_prefix="/gift-cards")


def _generate_code(tenant_id: int) -> str:
    """Generate a unique gift card code for this tenant."""
    alphabet = string.ascii_uppercase + string.digits
    for _ in range(20):
        code = "".join(secrets.choice(alphabet) for _ in range(12))
        code = f"{code[:4]}-{code[4:8]}-{code[8:12]}"
        if not GiftCard.query.filter_by(tenant_id=tenant_id, code=code).first():
            return code
    raise RuntimeError("Failed to generate unique gift card code")


@gift_cards_bp.route("/")
@login_required
@require_role("tenant_admin", "tenant_manager")
def index():
    cards = GiftCard.query.filter_by(
        tenant_id=g.tenant.id
    ).order_by(GiftCard.created_at.desc()).limit(200).all()
    return render_template("tenant/gift_cards/index.html", cards=cards)


@gift_cards_bp.route("/issue", methods=["GET", "POST"])
@login_required
@require_role("tenant_admin", "tenant_manager")
@demo_readonly
def issue():
    customers = Customer.query.filter_by(
        tenant_id=g.tenant.id, is_active=True).filter(
        Customer.deleted_at.is_(None)).order_by(Customer.name).limit(500).all()

    if request.method == "POST":
        try:
            value = float(request.form.get("value", 0))
            assert value > 0
        except (ValueError, AssertionError):
            return render_template("tenant/gift_cards/form.html",
                                   customers=customers, error="Value must be greater than 0.")

        customer_id = request.form.get("customer_id", type=int) or None
        expires_raw = request.form.get("expires_at", "").strip()
        expires_at = None
        if expires_raw:
            try:
                expires_at = datetime.fromisoformat(expires_raw)
            except ValueError:
                pass

        code = _generate_code(g.tenant.id)
        card = GiftCard(
            tenant_id=g.tenant.id, code=code,
            original_value=value, remaining_balance=value,
            issued_by=_user_db_id(),
            issued_to_customer_id=customer_id,
            expires_at=expires_at, is_active=True,
        )
        db.session.add(card)
        db.session.flush()
        log_tenant_action("gift_card.issue", "gift_card", card.id,
                          {"code": code, "value": value})
        db.session.commit()
        flash(f"Gift card issued: {code} (${value:.2f})", "success")
        return redirect(url_for("gift_cards.index"))
    return render_template("tenant/gift_cards/form.html", customers=customers)


@gift_cards_bp.route("/lookup")
@login_required
@require_role("tenant_admin", "tenant_manager")
def lookup():
    code = request.args.get("code", "").strip().upper()
    card = None
    if code:
        card = GiftCard.query.filter_by(
            tenant_id=g.tenant.id, code=code).first()
    return render_template("tenant/gift_cards/lookup.html",
                           card=card, code=code)


@gift_cards_bp.route("/<int:card_id>/deactivate", methods=["POST"])
@login_required
@require_role("tenant_admin")
@demo_readonly
def deactivate(card_id):
    card = GiftCard.query.filter_by(
        id=card_id, tenant_id=g.tenant.id).first_or_404()
    card.is_active = False
    log_tenant_action("gift_card.deactivate", "gift_card", card.id,
                      {"code": card.code})
    db.session.commit()
    flash(f"Gift card {card.code} deactivated.", "success")
    return redirect(url_for("gift_cards.index"))


def _user_db_id():
    from flask_login import current_user
    try:
        uid_str = current_user.get_id()
        return int(uid_str.split(":")[1]) if uid_str and ":" in uid_str else None
    except Exception:
        return None