<?php

namespace App\Services;

use App\Models\CustomerSpecialPricePackage;
use App\Models\Product;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Schema;

/**
 * قیمت ویژه مشتری — افزون بر buy_fee/sell_fee و cash_fee محصول.
 * تداخل: آخرین پکیج (updated_at، سپس id).
 */
class CustomerSpecialPricingService
{
    public const SETTING_KEY = 'customer_special_pricing';

    public function tablesReady(): bool
    {
        return Schema::hasTable('customer_special_price_packages')
            && Schema::hasTable('customer_special_price_package_customer')
            && Schema::hasTable('customer_special_price_package_product');
    }

    public function isEnabled(): bool
    {
        if (! $this->tablesReady()) {
            return false;
        }

        return app(ConfigService::class)->getBool(self::SETTING_KEY, false);
    }

    /**
     * @return array{package_id:int,title:string,profit_buy:int,profit_sell:int,show_product:bool}|null
     */
    public function ruleForCustomerProduct(int $customerId, int $productId): ?array
    {
        if (! $this->isEnabled() || $customerId <= 0 || $productId <= 0) {
            return null;
        }

        $row = CustomerSpecialPricePackage::query()
            ->active()
            ->whereHas('customers', fn ($q) => $q->where('customers.id', $customerId))
            ->whereHas('products', fn ($q) => $q->where('products.id', $productId))
            ->orderByDesc('updated_at')
            ->orderByDesc('id')
            ->first(['id', 'title', 'profit_buy', 'profit_sell', 'show_product', 'updated_at']);

        if (! $row) {
            return null;
        }

        return [
            'package_id' => (int) $row->id,
            'title' => (string) $row->title,
            'profit_buy' => (int) ($row->profit_buy ?? 0),
            'profit_sell' => (int) ($row->profit_sell ?? 0),
            'show_product' => (bool) $row->show_product,
        ];
    }

    /**
     * قوانین مؤثر برای مشتری — هر محصول یک قانون (آخرین پکیج).
     *
     * @return array<int, array{package_id:int,title:string,profit_buy:int,profit_sell:int,show_product:bool}>
     */
    public function rulesMapForCustomer(int $customerId): array
    {
        if (! $this->isEnabled() || $customerId <= 0) {
            return [];
        }

        $packages = CustomerSpecialPricePackage::query()
            ->active()
            ->whereHas('customers', fn ($q) => $q->where('customers.id', $customerId))
            ->with(['products:id'])
            ->orderByDesc('updated_at')
            ->orderByDesc('id')
            ->get(['id', 'title', 'profit_buy', 'profit_sell', 'show_product', 'updated_at']);

        $map = [];
        foreach ($packages as $package) {
            foreach ($package->products as $product) {
                $pid = (int) $product->id;
                if (isset($map[$pid])) {
                    continue;
                }
                $map[$pid] = [
                    'package_id' => (int) $package->id,
                    'title' => (string) $package->title,
                    'profit_buy' => (int) ($package->profit_buy ?? 0),
                    'profit_sell' => (int) ($package->profit_sell ?? 0),
                    'show_product' => (bool) $package->show_product,
                ];
            }
        }

        return $map;
    }

    public function profitForDirection(?array $rule, int $direction): int
    {
        if (! $rule) {
            return 0;
        }

        return $direction === 2
            ? (int) ($rule['profit_sell'] ?? 0)
            : (int) ($rule['profit_buy'] ?? 0);
    }

    /**
     * اعمال روی payload تابلو last (buy/sell/price_last) برای محصول اصلی یا اولین قانون آبشده.
     */
    public function applyToLastPayload(array $payload, int $customerId): array
    {
        if (! $this->isEnabled() || $customerId <= 0) {
            return $payload;
        }

        $mainId = app(ConfigService::class)->mainProductId();
        $rule = null;
        if ($mainId) {
            $rule = $this->ruleForCustomerProduct($customerId, (int) $mainId);
        }

        if (! $rule) {
            $map = $this->rulesMapForCustomer($customerId);
            $rule = $map ? reset($map) : null;
            if (is_array($rule) && ! ($rule['show_product'] ?? true)) {
                // فقط برای اختلاف قیمت؛ مخفی‌سازی روی لیست محصول است
            }
        }

        if (! $rule) {
            return $payload;
        }

        $buyExtra = (int) ($rule['profit_buy'] ?? 0);
        $sellExtra = (int) ($rule['profit_sell'] ?? 0);

        if (isset($payload['buy']) && (int) $payload['buy'] > 0 && $buyExtra !== 0) {
            $payload['buy'] = max(0, (int) $payload['buy'] + $buyExtra);
        }
        if (isset($payload['sell']) && (int) $payload['sell'] > 0 && $sellExtra !== 0) {
            $payload['sell'] = max(0, (int) $payload['sell'] - $sellExtra);
        }
        if (isset($payload['price_last']) && (int) $payload['price_last'] > 0 && $buyExtra !== 0) {
            $payload['price_last'] = max(0, (int) $payload['price_last'] + $buyExtra);
        }
        if (isset($payload['priceLast']) && (int) $payload['priceLast'] > 0 && $buyExtra !== 0) {
            $payload['priceLast'] = max(0, (int) $payload['priceLast'] + $buyExtra);
        }

        $payload['special_pricing'] = [
            'package_id' => $rule['package_id'],
            'title' => $rule['title'],
            'profit_buy' => $buyExtra,
            'profit_sell' => $sellExtra,
        ];

        return $payload;
    }

    /**
     * روی کالکشن محصول: ویژه را روی مدل می‌نشاند و در صورت نیاز show را false می‌کند.
     *
     * @param  Collection<int, Product>|iterable<Product>  $products
     */
    public function applyToProducts($products, int $customerId): void
    {
        if (! $this->isEnabled() || $customerId <= 0) {
            return;
        }

        $map = $this->rulesMapForCustomer($customerId);
        if ($map === []) {
            return;
        }

        $collection = $products instanceof Collection ? $products : collect($products);
        foreach ($collection as $product) {
            if (! $product instanceof Product) {
                continue;
            }
            $pid = (int) ($product->id ?? 0);
            $rule = $map[$pid] ?? null;
            if (! $rule) {
                continue;
            }

            $product->setAttribute('special_profit_buy', (int) $rule['profit_buy']);
            $product->setAttribute('special_profit_sell', (int) $rule['profit_sell']);
            $product->setAttribute('special_package_id', (int) $rule['package_id']);
            $product->setAttribute('special_package_title', (string) $rule['title']);

            if (! ($rule['show_product'] ?? true)) {
                $product->setAttribute('show', false);
            }
        }
    }

    /**
     * هشدار تداخل: مشتری+محصول در پکیج دیگری هم هست.
     *
     * @param  list<int>  $customerIds
     * @param  list<int>  $productIds
     * @return list<string>
     */
    public function overlapWarnings(array $customerIds, array $productIds, ?int $excludePackageId = null): array
    {
        if (! $this->tablesReady() || $customerIds === [] || $productIds === []) {
            return [];
        }

        $customerIds = array_values(array_unique(array_map('intval', $customerIds)));
        $productIds = array_values(array_unique(array_map('intval', $productIds)));

        $q = DB::table('customer_special_price_packages as p')
            ->join('customer_special_price_package_customer as pc', 'pc.package_id', '=', 'p.id')
            ->join('customer_special_price_package_product as pp', 'pp.package_id', '=', 'p.id')
            ->join('customers as c', 'c.id', '=', 'pc.customer_id')
            ->join('products as pr', 'pr.id', '=', 'pp.product_id')
            ->where('p.is_active', true)
            ->whereIn('pc.customer_id', $customerIds)
            ->whereIn('pp.product_id', $productIds)
            ->select([
                'p.id as package_id',
                'p.title as package_title',
                'c.id as customer_id',
                'c.name as customer_name',
                'pr.id as product_id',
                'pr.title as product_title',
            ]);

        if ($excludePackageId) {
            $q->where('p.id', '!=', $excludePackageId);
        }

        $rows = $q->limit(50)->get();
        if ($rows->isEmpty()) {
            return [];
        }

        $warnings = [];
        foreach ($rows as $row) {
            $warnings[] = sprintf(
                'تداخل: مشتری «%s» (#%d) و محصول «%s» (#%d) در پکیج «%s» (#%d) هم هست — آخرین پکیج اعمال می‌شود.',
                $row->customer_name ?: '-',
                (int) $row->customer_id,
                $row->product_title ?: '-',
                (int) $row->product_id,
                $row->package_title ?: '-',
                (int) $row->package_id
            );
        }

        return $warnings;
    }

    /** payload سبک برای SSE / me */
    public function clientPayloadForCustomer(int $customerId): array
    {
        $map = $this->rulesMapForCustomer($customerId);
        $products = [];
        foreach ($map as $productId => $rule) {
            $products[] = array_merge(['product_id' => (int) $productId], $rule);
        }

        $mainId = app(ConfigService::class)->mainProductId();
        $board = null;
        if ($mainId && isset($map[(int) $mainId])) {
            $board = $map[(int) $mainId];
        } elseif ($products !== []) {
            $board = $products[0];
        }

        return [
            'enabled' => $this->isEnabled(),
            'products' => $products,
            'board' => $board,
        ];
    }
}