<?php

namespace Modules\Core\Checkout\Services;

use Lunar\Exceptions\FingerprintMismatchException;
use Lunar\Exceptions\Carts\CartException;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\Event;
use Lunar\Base\Addressable;
use Lunar\DataTypes\ShippingOption;
use Lunar\Facades\ShippingManifest;
use Lunar\Models\Cart;
use Lunar\Models\Order;
use Modules\Core\Cart\Services\CartService;
use Modules\Core\Checkout\Contracts\PaymentDriver;
use Modules\Core\Checkout\Events\BillingAddressSet;
use Modules\Core\Checkout\Events\OrderPlaced;
use Modules\Core\Checkout\Events\PaymentMethodSelected;
use Modules\Core\Checkout\Events\ShippingAddressSet;
use Modules\Core\Checkout\Events\ShippingOptionSelected;
use Modules\Core\Checkout\Exceptions\InvalidShippingOptionException;
use Modules\Core\Checkout\Exceptions\UnknownPaymentTypeException;
use Modules\Core\Payment\Models\PaymentMethod;

/**
 * Storefront-facing checkout operations, mirroring
 * Modules\Core\Cart\Services\CartService's shape — one boboko-owned API a
 * storefront calls, keeping Lunar's own Cart/ShippingManifest primitives an
 * implementation detail. See docs/checkout.md for the full design —
 * Checkout is the middle of a three-stage lifecycle (Cart → Checkout →
 * Order): it owns the placement moment itself (address, shipping selection,
 * placeOrder()) and ends the instant an Order exists. What happens to that
 * Order afterward (status transitions, fulfillment) is deliberately out of
 * scope here — see OrderPlaced's docblock.
 *
 * Depends on CartService for cart access rather than reaching into
 * Lunar\Facades\CartSession directly a second time, so Checkout stays
 * layered on top of Cart's own service boundary instead of duplicating it.
 */
class CheckoutService
{
    public function __construct(
        private readonly CartService $cart,
    ) {}

    public function setShippingAddress(array|Addressable $address): Cart
    {
        $cart = $this->cart->currentOrCreate()->setShippingAddress($address);

        Event::dispatch(new ShippingAddressSet($cart, $address));

        return $cart;
    }

    public function setBillingAddress(array|Addressable $address): Cart
    {
        $cart = $this->cart->currentOrCreate()->setBillingAddress($address);

        Event::dispatch(new BillingAddressSet($cart, $address));

        return $cart;
    }

    /**
     * Every shipping option currently available for the cart — already
     * fully backed by the merged Shipping-Carriers work: this runs every
     * registered Lunar\Shipping\Interfaces\ShippingRateInterface driver
     * (ACS/Box Now live-rate quoting alongside table-rate-shipping's own
     * flat-rate/free-shipping/collection drivers) through
     * ShippingManifest's pipeline. No rate-resolution logic lives here —
     * this is a thin pass-through.
     *
     * @return Collection<int, ShippingOption>
     */
    public function getShippingOptions(): Collection
    {
        return ShippingManifest::getOptions($this->cart->currentOrCreate());
    }

    /**
     * @throws InvalidShippingOptionException if $identifier doesn't resolve
     *   to a real, currently-available option for the cart
     */
    public function selectShippingOption(string $identifier): Cart
    {
        $cartBefore = $this->cart->currentOrCreate();
        $option = ShippingManifest::getOption($cartBefore, $identifier);

        if ($option === null) {
            throw new InvalidShippingOptionException($identifier);
        }

        $cart = $cartBefore->setShippingOption($option);

        Event::dispatch(new ShippingOptionSelected($cart, $option));

        return $cart;
    }

    /**
     * $fingerprint is mandatory, not optional — the caller must prove the
     * cart total the shopper last saw (Cart::fingerprint()) still matches
     * before an order is placed. Cart::checkFingerprint() throws Lunar's own
     * FingerprintMismatchException on a mismatch (a line's price changed,
     * stock adjusted the total, another tab modified the cart) rather than
     * silently placing an order at a different total than what was shown.
     *
     * Not called directly by a storefront — see confirmPayment(), which is
     * the only caller and supplies the fingerprint captured in
     * selectPaymentMethod(), not one the storefront has to obtain itself.
     *
     * No exception wrapping: Lunar\Validation\Cart\ValidateCartForOrderCreation
     * (run inside Cart::createOrder()) already throws
     * Lunar\Exceptions\Carts\CartException with a field-keyed MessageBag
     * ($exception->errors()) for address/shipping-option validation and the
     * duplicate-order guard — already the right shape for a storefront to
     * render as form errors directly. FingerprintMismatchException
     * propagates the same way, for the same reason.
     *
     * @throws FingerprintMismatchException
     * @throws CartException
     */
    public function placeOrder(string $fingerprint): Order
    {
        $cart = $this->cart->currentOrCreate();
        $cart->checkFingerprint($fingerprint);

        $order = $cart->createOrder();

        Event::dispatch(new OrderPlaced($order));

        return $order;
    }

    /**
     * Every payment type currently offered to the storefront — every key
     * in config('lunar.payments.types') that is BOTH administratively
     * enabled (Modules\Core\Payment\Models\PaymentMethod::enabled) AND
     * whose registered PaymentDriver reports itself usable right now
     * (PaymentDriver::isConfigured() — e.g. Stripe with no API key set is
     * never offered, regardless of the enabled toggle). A type with no
     * PaymentMethod row at all (never seeded) is treated as not offered,
     * same as disabled — nothing here creates one; see
     * InstallLunarCommand::seedPaymentMethods().
     *
     * @return array<string>
     */
    public function getPaymentMethods(): array
    {
        return PaymentMethod::where('enabled', true)
            ->pluck('type')
            ->filter(fn (string $type) => $this->resolvePaymentDriver($type)?->isConfigured() ?? false)
            ->values()
            ->all();
    }

    /**
     * Records which payment type the shopper picked (Cart::meta
     * ['payment_method']) — read by e.g. Modules\Core\Payment\Pipelines\
     * Cart\ApplyCashOnDeliveryFee to add that type's own cart-total
     * adjustments before recalculation.
     *
     * Also snapshots Cart::fingerprint() into meta, *after* saving the
     * chosen type — the fingerprint has to reflect the final total
     * including any payment-type-specific adjustment (e.g. a COD
     * surcharge), which only exists once payment_method is set and the
     * cart recalculates. Captured here, server-side, rather than asked of
     * the storefront: this is the last moment before confirmPayment() that
     * the shopper's reviewed total is known, and confirmPayment() reads it
     * back internally instead of taking a fingerprint parameter — a
     * storefront should never need to know Cart::fingerprint() exists.
     *
     * Does not itself call a PaymentDriver — selecting a method and
     * confirming payment against it are deliberately separate steps, same
     * as selecting a shipping option happens before placing the order.
     *
     * @throws UnknownPaymentTypeException if $type isn't currently offered
     *   — see getPaymentMethods() for what that means (registered,
     *   administratively enabled, and its driver reports itself usable)
     */
    public function selectPaymentMethod(string $type): Cart
    {
        if (! in_array($type, $this->getPaymentMethods(), true)) {
            throw new UnknownPaymentTypeException($type);
        }

        $cart = $this->cart->currentOrCreate();
        $cart->meta = [...$cart->meta->toArray(), 'payment_method' => $type];
        $cart->save();

        $cart = $cart->calculate();
        $cart->meta = [...$cart->meta->toArray(), 'checkout_fingerprint' => $cart->fingerprint()];
        $cart->save();

        Event::dispatch(new PaymentMethodSelected($cart, $type));

        return $cart;
    }

    /**
     * Resolves $type's registered PaymentDriver and calls confirm() —
     * the driver decides whether/when the order actually gets placed (see
     * Modules\Core\Checkout\Contracts\PaymentDriver's docblock). $data
     * carries whatever that driver needs (Stripe's payment_intent id, a
     * future redirect-based provider's callback payload).
     *
     * The fingerprint passed to the driver is the one captured by
     * selectPaymentMethod(), not supplied by the caller — see that
     * method's docblock. Throws the same FingerprintMismatchException a
     * caller-supplied one would if the cart's total has since changed;
     * missing entirely (selectPaymentMethod() was never called for this
     * cart) is treated the same as a mismatch, not a different error.
     *
     * @param  array<string, mixed>  $data
     *
     * @throws UnknownPaymentTypeException if $type isn't currently offered
     *   (see getPaymentMethods()) — re-checked here, not just in
     *   selectPaymentMethod(), since a type could be disabled between
     *   selection and confirmation
     * @throws \Lunar\Exceptions\FingerprintMismatchException
     * @throws \Lunar\Exceptions\Carts\CartException
     */
    public function confirmPayment(string $type, array $data = []): Order
    {
        if (! in_array($type, $this->getPaymentMethods(), true)) {
            throw new UnknownPaymentTypeException($type);
        }

        $cart = $this->cart->currentOrCreate();
        $fingerprint = $cart->meta['checkout_fingerprint'] ?? '';

        return $this->resolvePaymentDriver($type)->confirm($cart, $type, $fingerprint, $data);
    }

    /**
     * Resolves $type's registered PaymentDriver, or null if $type has no
     * 'payment_driver' registered in config('lunar.payments.types.<type>')
     * at all — deliberately non-throwing so getPaymentMethods() can filter
     * unresolvable types silently rather than treating "not registered"
     * as an error condition when just checking availability.
     */
    private function resolvePaymentDriver(string $type): ?PaymentDriver
    {
        $driverClass = config("lunar.payments.types.{$type}.payment_driver");

        return $driverClass ? app($driverClass) : null;
    }
}