<?php

namespace App\Services\Pos;

use App\Models\PosSale;
use App\Services\Crm\CrmClient;
use Illuminate\Support\Facades\Log;
use Illuminate\Validation\ValidationException;
use RuntimeException;

/**
 * POS-facing loyalty adapter. CRM is the source of truth for balances and rules.
 */
class PosLoyaltyService
{
    public function program(string $ownerRef): ?array
    {
        try {
            return CrmClient::for($ownerRef)->loyaltyProgram();
        } catch (\Throwable $e) {
            Log::debug('loyalty.program_unavailable', ['owner' => $ownerRef, 'error' => $e->getMessage()]);

            return null;
        }
    }

    public function isEnabled(string $ownerRef): bool
    {
        $program = $this->program($ownerRef);

        return (bool) ($program['enabled'] ?? false);
    }

    /**
     * @return array<string, mixed>|null
     */
    public function snapshot(string $ownerRef, int $crmCustomerId, int $amountMinor = 0): ?array
    {
        try {
            return CrmClient::for($ownerRef)->customerLoyalty($crmCustomerId, $amountMinor);
        } catch (\Throwable $e) {
            Log::debug('loyalty.snapshot_failed', [
                'owner' => $ownerRef,
                'customer' => $crmCustomerId,
                'error' => $e->getMessage(),
            ]);

            return null;
        }
    }

    /**
     * @return array<string, mixed>|null
     */
    public function quote(string $ownerRef, int $crmCustomerId, int $subtotalMinor, int $redeemPoints = 0): ?array
    {
        try {
            return CrmClient::for($ownerRef)->loyaltyQuote([
                'customer_id' => $crmCustomerId,
                'subtotal_minor' => $subtotalMinor,
                'redeem_points' => $redeemPoints,
            ]);
        } catch (\Throwable $e) {
            Log::debug('loyalty.quote_failed', ['error' => $e->getMessage()]);

            return null;
        }
    }

    /**
     * Apply redeem against CRM and return discount details for the sale.
     *
     * @return array{points: int, discount_minor: int, external_ref: string, balance: int}
     */
    public function redeemForSale(PosSale $sale, int $redeemPoints): array
    {
        if (! $sale->crm_customer_id || $redeemPoints <= 0) {
            return ['points' => 0, 'discount_minor' => 0, 'external_ref' => '', 'balance' => 0];
        }

        $externalRef = $sale->loyalty_external_ref ?: ('pos-sale-'.$sale->id.'-'.$sale->reference);

        try {
            $result = CrmClient::for($sale->owner_ref)->loyaltyRedeem([
                'customer_id' => (int) $sale->crm_customer_id,
                'subtotal_minor' => (int) $sale->subtotal_minor,
                'redeem_points' => $redeemPoints,
                'external_ref' => $externalRef,
                'source' => 'pos',
                'description' => 'POS '.$sale->reference,
            ]);
        } catch (ValidationException $e) {
            throw new RuntimeException(collect($e->errors())->flatten()->first() ?: 'Could not redeem loyalty points.');
        } catch (\Throwable $e) {
            throw new RuntimeException('Could not redeem loyalty points. Check CRM connectivity.');
        }

        return [
            'points' => (int) ($result['points'] ?? 0),
            'discount_minor' => (int) ($result['discount_minor'] ?? 0),
            'external_ref' => $externalRef,
            'balance' => (int) ($result['balance'] ?? 0),
        ];
    }

    public function earnForSale(PosSale $sale): int
    {
        if (! $sale->crm_customer_id) {
            return 0;
        }

        $externalRef = $sale->loyalty_external_ref ?: ('pos-sale-'.$sale->id.'-'.$sale->reference);
        // Earn on net merchandise (exclude tip); tips are staff gratuity.
        $amount = max(0, (int) $sale->subtotal_minor - (int) $sale->loyalty_discount_minor);

        try {
            $result = CrmClient::for($sale->owner_ref)->loyaltyEarn([
                'customer_id' => (int) $sale->crm_customer_id,
                'amount_minor' => $amount,
                'external_ref' => $externalRef,
                'source' => 'pos',
                'description' => 'POS '.$sale->reference,
            ]);
        } catch (\Throwable $e) {
            Log::warning('loyalty.earn_failed', [
                'sale' => $sale->id,
                'error' => $e->getMessage(),
            ]);

            return 0;
        }

        $points = (int) ($result['points'] ?? 0);
        if ($points > 0 || ! $sale->loyalty_points_earned) {
            $sale->forceFill([
                'loyalty_points_earned' => $points,
                'loyalty_external_ref' => $externalRef,
            ])->save();
        }

        return $points;
    }

    public function reverseForSale(PosSale $sale): void
    {
        $ref = $sale->loyalty_external_ref;
        if (! $ref && ($sale->loyalty_points_redeemed || $sale->loyalty_points_earned)) {
            $ref = 'pos-sale-'.$sale->id.'-'.$sale->reference;
        }
        if (! $ref) {
            return;
        }

        try {
            CrmClient::for($sale->owner_ref)->loyaltyReverse([
                'external_ref' => $ref,
                'source' => 'pos',
            ]);
        } catch (\Throwable $e) {
            Log::warning('loyalty.reverse_failed', [
                'sale' => $sale->id,
                'error' => $e->getMessage(),
            ]);
        }
    }

    /**
     * Payload for customer display.
     *
     * @return array<string, mixed>|null
     */
    public function displayPayload(?array $snapshot, int $redeemPoints = 0, int $earnPoints = 0): ?array
    {
        if (! $snapshot || ! ($snapshot['program']['enabled'] ?? $snapshot['points_balance'] ?? false)) {
            if (! $snapshot) {
                return null;
            }
        }

        if (! ($snapshot['program']['enabled'] ?? false)) {
            return null;
        }

        return [
            'label' => $snapshot['label'] ?? ($snapshot['program']['name'] ?? 'Rewards'),
            'points_balance' => (int) ($snapshot['points_balance'] ?? 0),
            'points_earn' => $earnPoints ?: (int) ($snapshot['points_earn'] ?? 0),
            'points_redeem' => $redeemPoints,
        ];
    }
}