<?php

namespace Modules\SupplyChain\Services;

use App\Utils\ModuleUtil;
use App\Variation;
use Carbon\Carbon;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Schema;
use Modules\IndustrialEngineering\Models\MrpRun;
use Modules\SupplyChain\Models\DemandForecast;

class SupplyChainIntegrationService
{
    public function __construct(
        protected DemandForecastService $demandForecastService,
        protected RfqService $rfqService,
        protected ModuleUtil $moduleUtil
    ) {
    }

    /**
     * Hook after IE MRP run — import shortages as demand forecasts and optionally create RFQ.
     *
     * @param  array<string, mixed>|MrpRun  $runOrData
     * @return array<string, mixed>
     */
    public function afterMrpRun($runOrData): array
    {
        if (! $this->moduleUtil->isModuleInstalled('SupplyChain')) {
            return ['forecasts' => 0, 'rfq_id' => null];
        }

        $run = $runOrData instanceof MrpRun ? $runOrData : null;
        $businessId = $run?->business_id ?? (int) ($runOrData['business_id'] ?? 0);
        $analysis = $run?->shortage_analysis ?? ($runOrData['shortage_analysis'] ?? []);
        $shortages = $analysis['shortages'] ?? [];

        if ($businessId <= 0 || empty($shortages)) {
            return ['forecasts' => 0, 'rfq_id' => null];
        }

        $forecastMonth = now()->addMonth()->startOfMonth();
        $count = 0;

        foreach ($shortages as $shortage) {
            $productId = $this->resolveProductId($shortage);
            if (! $productId) {
                continue;
            }

            DemandForecast::updateOrCreate(
                [
                    'business_id' => $businessId,
                    'product_id' => $productId,
                    'variation_id' => ! empty($shortage['variation_id']) ? (int) $shortage['variation_id'] : null,
                    'forecast_month' => $forecastMonth->toDateString(),
                    'method' => 'mrp_shortage',
                ],
                [
                    'forecast_qty' => (float) ($shortage['shortage_qty'] ?? 0),
                    'confidence' => 85.0,
                    'source' => 'mrp',
                    'meta' => [
                        'mrp_run_id' => $run?->id,
                        'mrp_run_code' => $run?->run_code,
                    ],
                ]
            );
            $count++;
        }

        return ['forecasts' => $count, 'rfq_id' => null];
    }

    /**
     * Create RFQ from latest MRP run shortages.
     */
    public function createRfqFromMrpRun(int $businessId, int $mrpRunId, ?array $supplierIds = null): ?int
    {
        if (! $this->moduleUtil->isModuleInstalled('IndustrialEngineering')
            || ! Schema::hasTable('ie_mrp_runs')) {
            return null;
        }

        $run = MrpRun::forBusiness($businessId)->find($mrpRunId);
        if (! $run || empty($run->shortage_analysis['shortages'])) {
            return null;
        }

        $rfq = $this->rfqService->createFromMrpShortages(
            $businessId,
            $run->shortage_analysis['shortages'],
            __('supplychain::lang.rfq_from_mrp_run', ['code' => $run->run_code]),
            $supplierIds
        );

        return $rfq->id;
    }

    /**
     * Demand inputs for MRP — merges forecast qty into planned demand.
     *
     * @return array<int, float> variation_id => additional_qty
     */
    public function getMrpDemandInputs(int $businessId, ?Carbon $month = null): array
    {
        try {
            return $this->demandForecastService->getForecastByVariation($businessId, $month);
        } catch (\Throwable $e) {
            Log::warning('SupplyChain MRP demand inputs failed: '.$e->getMessage());

            return [];
        }
    }

    /**
     * Apply demand forecast adjustments to MRP shortage analysis.
     *
     * @param  array<string, mixed>  $analysis
     * @return array<string, mixed>
     */
    public function enrichMrpAnalysis(int $businessId, array $analysis): array
    {
        $forecasts = $this->getMrpDemandInputs($businessId);
        if (empty($forecasts) || empty($analysis['shortages'])) {
            return $analysis;
        }

        foreach ($analysis['shortages'] as $idx => $shortage) {
            $variationId = (int) ($shortage['variation_id'] ?? 0);
            if ($variationId && isset($forecasts[$variationId])) {
                $additional = $forecasts[$variationId];
                $currentShortage = (float) ($shortage['shortage_qty'] ?? 0);
                $analysis['shortages'][$idx]['forecast_demand_qty'] = $additional;
                $analysis['shortages'][$idx]['shortage_qty'] = $currentShortage + $additional;
            }
        }

        $analysis['supply_chain_forecast_applied'] = true;

        return $analysis;
    }

    /**
     * @param  array<string, mixed>  $shortage
     */
    protected function resolveProductId(array $shortage): ?int
    {
        if (! empty($shortage['product_id'])) {
            return (int) $shortage['product_id'];
        }

        if (! empty($shortage['variation_id'])) {
            $productId = Variation::where('id', (int) $shortage['variation_id'])->value('product_id');

            return $productId ? (int) $productId : null;
        }

        return null;
    }
}