<?php
namespace App\Services\Catalog;

use App\Models\Fornitore;
use App\Models\Product;
use App\Models\ProductIdentifier;
use App\Models\ProductOffer;
use App\Models\ProductSerial;
use Carbon\Carbon;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Str;

class ContabilitaMysqlSerialImportService
{
    public function __construct(
        private readonly ProductOfferService $productOfferService,
    ) {
    }

    /**
     * Import invoices, products, and serials from external MySQL accounting database (e.g. arc_nehr).
     *
     * @return array{
     *     supplier_code: string,
     *     fornitore_id: int,
     *     invoices_count: int,
     *     lines_processed: int,
     *     products_created: int,
     *     identifiers_created: int,
     *     serials_created: int,
     *     serials_updated: int,
     *     dry_run: bool
     * }
     */
    public function importForSupplier(string $supplierCode = 'NCOMSRL', ?int $targetFornitoreId = null, bool $dryRun = false): array
    {
        $stats = [
            'supplier_code'       => $supplierCode,
            'fornitore_id'        => 0,
            'invoices_count'      => 0,
            'lines_processed'     => 0,
            'products_created'    => 0,
            'identifiers_created' => 0,
            'serials_created'     => 0,
            'serials_updated'     => 0,
            'dry_run'             => $dryRun,
        ];

        // 1. Resolve or create local Fornitore in NetGescon
        $fornitore = $targetFornitoreId ? Fornitore::query()->find($targetFornitoreId) : null;

        if (! $fornitore instanceof Fornitore) {
            $fornitore = Fornitore::query()
                ->where('codice_univoco', $supplierCode)
                ->orWhere('ragione_sociale', 'like', '%' . $supplierCode . '%')
                ->orWhere('partita_iva', '14001151001')
                ->first();
        }

        // Fetch supplier info from remote accounting database if not found locally
        if (! $fornitore instanceof Fornitore) {
            $remoteSupplier = DB::connection('contabilita_mysql')
                ->table('fet')
                ->where('frn_codice', $supplierCode)
                ->first([
                    'frn_codice', 'frn_descrizione', 'frn_partita_iva', 'frn_codice_fiscale',
                    'frn_via', 'frn_numero_civico', 'frn_cap', 'frn_citta', 'frn_provincia',
                ]);

            if ($remoteSupplier) {
                $piva = trim((string) ($remoteSupplier->frn_partita_iva ?: $remoteSupplier->frn_codice_fiscale));
                $fornitore = Fornitore::query()->where('partita_iva', $piva)->first();

                if (! $fornitore && ! $dryRun) {
                    $adminId = Fornitore::query()->where('partita_iva', '10055221005')->value('amministratore_id') ?: 13;
                    $fornitore = Fornitore::query()->create([
                        'ragione_sociale'   => trim((string) $remoteSupplier->frn_descrizione) ?: $supplierCode,
                        'nome'              => '',
                        'cognome'           => trim((string) $remoteSupplier->frn_descrizione) ?: $supplierCode,
                        'partita_iva'       => $piva,
                        'codice_fiscale'    => trim((string) ($remoteSupplier->frn_codice_fiscale ?: $piva)),
                        'indirizzo'         => trim((string) $remoteSupplier->frn_via),
                        'civico'            => trim((string) $remoteSupplier->frn_numero_civico),
                        'cap'               => trim((string) $remoteSupplier->frn_cap),
                        'citta'             => trim((string) $remoteSupplier->frn_citta),
                        'provincia'         => trim((string) $remoteSupplier->frn_provincia),
                        'nazione'           => 'IT',
                        'amministratore_id' => $adminId,
                        'codice_univoco'    => substr($supplierCode, 0, 8),
                        'note'              => 'Fornitore importato da contabilità MySQL Target Cross arc_nehr',
                    ]);
                }
            }
        }

        if (! $fornitore instanceof Fornitore && ! $dryRun) {
            throw new \RuntimeException("Fornitore locale non trovato né creabile per il codice '{$supplierCode}'.");
        }

        $fornitoreId = $fornitore ? (int) $fornitore->id : 0;
        $stats['fornitore_id'] = $fornitoreId;

        // Ensure Nethome merges this supplier into its catalog scope
        if ($fornitoreId > 0 && ! $dryRun) {
            $nethome = Fornitore::query()->where('partita_iva', '10055221005')->first();
            if ($nethome instanceof Fornitore && (int) $nethome->id !== $fornitoreId) {
                $cfg = (array) ($nethome->operational_config ?? []);
                $merged = array_unique(array_merge((array) data_get($cfg, 'merged_supplier_ids', []), [$fornitoreId]));
                $cfg['merged_supplier_ids'] = array_values($merged);
                $nethome->operational_config = $cfg;
                $nethome->save();
            }
        }

        // 2. Fetch rows from contabilita_mysql
        $rows = DB::connection('contabilita_mysql')
            ->table('fea')
            ->join('fet', 'fea.progressivo', '=', 'fet.progressivo')
            ->where('fet.frn_codice', $supplierCode)
            ->select([
                'fea.id as fea_id',
                'fea.progressivo',
                'fea.riga',
                'fea.quantita',
                'fea.importo',
                'fea.note',
                'fea.art_codice',
                'fet.numero_documento',
                'fet.data_documento',
                'fet.id_sdi',
                'fet.frn_descrizione',
            ])
            ->orderBy('fet.data_documento', 'asc')
            ->orderBy('fea.progressivo', 'asc')
            ->orderBy('fea.riga', 'asc')
            ->get();

        $seenInvoices = [];

        foreach ($rows as $row) {
            $stats['lines_processed']++;
            $invKey = (string) $row->numero_documento . '-' . (string) $row->data_documento;
            if (! isset($seenInvoices[$invKey])) {
                $seenInvoices[$invKey] = true;
                $stats['invoices_count']++;
            }

            $note = (string) ($row->note ?? '');
            $serials = $this->extractSerials($note);
            $productInfo = $this->extractProductInfo($note, (string) ($row->art_codice ?? ''));

            if (empty($productInfo['title']) && empty($serials)) {
                continue;
            }

            $qty = max(1.0, (float) ($row->quantita ?? 1.0));
            $lineAmount = (float) ($row->importo ?? 0.0);
            $unitPrice = round($lineAmount / $qty, 2);

            $purchaseDate = null;
            if (! empty($row->data_documento)) {
                try {
                    $purchaseDate = Carbon::parse($row->data_documento);
                } catch (\Throwable) {
                    $purchaseDate = null;
                }
            }

            if ($dryRun) {
                $stats['serials_created'] += count($serials);
                continue;
            }

            // 3. Resolve or create Product
            $product = $this->resolveOrCreateProduct($fornitore, $productInfo, $unitPrice);
            if ($product->wasRecentlyCreated) {
                $stats['products_created']++;
            }

            // 4. Upsert Supplier SKU Identifier (checking normalized_code unique scope)
            if (! empty($productInfo['sku'])) {
                $normCode = preg_replace('/[^A-Za-z0-9]+/', '', strtoupper($productInfo['sku']));
                if ($normCode !== '') {
                    $ident = ProductIdentifier::query()
                        ->where('fornitore_id', $fornitoreId)
                        ->where('code_type', 'supplier_sku')
                        ->where('normalized_code', $normCode)
                        ->first();

                    if (! $ident) {
                        ProductIdentifier::query()->create([
                            'product_id'        => (int) $product->id,
                            'fornitore_id'      => $fornitoreId,
                            'code_value'        => $productInfo['sku'],
                            'code_type'         => 'supplier_sku',
                            'code_role'         => 'supplier',
                            'normalized_code'   => $normCode,
                            'source'            => 'contabilita_mysql',
                            'source_reference'  => 'fet:' . $row->progressivo . ';sdi:' . $row->id_sdi,
                            'is_primary'        => true,
                        ]);
                        $stats['identifiers_created']++;
                    }
                }
            }

            // 5. Upsert Product Offer using ProductOfferService
            $this->productOfferService->syncInternalSupplierOffer($product, $fornitore, [
                'external_sku' => $productInfo['sku'] ?: null,
                'title'        => (string) ($product->name ?? $productInfo['title']),
                'currency'     => 'EUR',
                'price_amount' => $unitPrice > 0 ? $unitPrice : null,
                'availability' => 'purchased_from_supplier',
                'meta'         => [
                    'source'              => 'contabilita_mysql',
                    'invoice_number'      => (string) $row->numero_documento,
                    'invoice_date'        => $purchaseDate?->format('Y-m-d H:i:s'),
                    'invoice_line'        => $row->riga,
                    'purchase_quantity'   => $qty,
                    'purchase_total_line' => $lineAmount,
                    'id_sdi'              => (string) $row->id_sdi,
                ],
            ]);

            // 6. Upsert Serial Numbers
            foreach ($serials as $serialNumber) {
                $serialNumber = trim($serialNumber);
                if ($serialNumber === '') {
                    continue;
                }

                $existingSerial = ProductSerial::query()
                    ->where('fornitore_id', $fornitoreId)
                    ->where('serial_number', $serialNumber)
                    ->first();

                $sourceRef = 'fet:' . $row->progressivo . ';fea:' . $row->fea_id . ';sdi:' . $row->id_sdi;

                if ($existingSerial instanceof ProductSerial) {
                    $dirty = false;
                    if ($existingSerial->purchase_price === null && $unitPrice > 0) {
                        $existingSerial->purchase_price = $unitPrice;
                        $dirty = true;
                    }
                    if ($existingSerial->purchase_date === null && $purchaseDate) {
                        $existingSerial->purchase_date = $purchaseDate;
                        $dirty = true;
                    }
                    if (empty($existingSerial->purchase_invoice_ref) && ! empty($row->numero_documento)) {
                        $existingSerial->purchase_invoice_ref = trim((string) $row->numero_documento);
                        $dirty = true;
                    }
                    if ($dirty) {
                        $existingSerial->save();
                        $stats['serials_updated']++;
                    }
                } else {
                    ProductSerial::query()->create([
                        'fornitore_id'          => $fornitoreId,
                        'product_id'            => (int) $product->id,
                        'customer_name'         => null,
                        'product_model'         => $product->name,
                        'product_code'          => $productInfo['sku'] ?: $product->internal_code,
                        'serial_number'         => $serialNumber,
                        'serial_number_2'       => null,
                        'purchase_date'         => $purchaseDate,
                        'purchase_price'        => $unitPrice > 0 ? $unitPrice : null,
                        'purchase_currency'     => 'EUR',
                        'purchase_tax_rate'     => 22.00,
                        'purchase_invoice_ref'  => trim((string) $row->numero_documento),
                        'purchase_invoice_line' => (int) ($row->riga ?? 1),
                        'internal_notes'        => 'Importato da contabilità MySQL Target Cross arc_nehr (SDI: ' . $row->id_sdi . ')',
                        'source'                => 'contabilita_mysql',
                        'source_reference'      => $sourceRef,
                    ]);
                    $stats['serials_created']++;
                }
            }
        }

        return $stats;
    }

    /**
     * Extract serial numbers from note text.
     *
     * @return array<int, string>
     */
    public function extractSerials(string $text): array
    {
        $serials = [];

        if (preg_match_all('/\b(?:S\/?N|SERIALE|SERIAL)\b\s*[:#-]?\s*([^\n\r]+)/iu', $text, $matches)) {
            foreach ($matches[1] as $block) {
                $block = preg_replace('/\b(?:CODICI|CODICE|INTERNO|NOTE|GARANZIA).*$/i', '', $block);
                $parts = preg_split('/[,;\/]+|\s{2,}/', (string) $block);

                foreach ($parts as $p) {
                    $clean = trim($p, " \t\n\r\0\x0B:,.-_");
                    if (strlen($clean) >= 4 && preg_match('/^[A-Za-z0-9_-]+$/i', $clean)) {
                        $serials[] = strtoupper($clean);
                    }
                }
            }
        }

        return array_values(array_unique($serials));
    }

    /**
     * Extract product title, brand, model, and SKU from note text.
     *
     * @return array{title: string, brand: ?string, model: ?string, sku: string}
     */
    public function extractProductInfo(string $text, ?string $artCode): array
    {
        $title = '';
        if (str_contains($text, '//')) {
            $parts = explode('//', $text, 2);
            $prefix = trim($parts[0]);
            $title = $prefix;

            $genericCategories = [
                'ALL IN ONE', 'NOTEBOOK', 'NOTEBOOK PORTATILI',
                'ULTRABOOK TABLET PC 2 IN 1 PORTATILI', 'PC DESKTOP', 'COMPUTER',
            ];
            if (strlen($prefix) < 15 || in_array(strtoupper($prefix), $genericCategories, true)) {
                $after = trim($parts[1]);
                if (preg_match('/^([^\n\r]+?)(?:\s+S\/N|\s+S\/n|\s+CODICI|$)/iu', $after, $m)) {
                    $title = trim($m[1]);
                }
            }
        } else {
            $lines = explode("\n", $text);
            $title = trim($lines[0]);
        }

        $title = preg_replace('/\s+S\/[Nn].*$/i', '', $title);
        $title = trim($title, " -/,.");

        $brand = null;
        $knownBrands = ['HP', 'DELL', 'LENOVO', 'APPLE', 'MACBOOK', 'IPHONE', 'ASUS', 'ACER', 'SAMSUNG', 'FUJITSU'];
        foreach ($knownBrands as $b) {
            if (stripos($title, $b) !== false) {
                $brand = ($b === 'MACBOOK' || $b === 'IPHONE') ? 'APPLE' : $b;
                break;
            }
        }

        $model = null;
        if (preg_match('/\b(PROONE\s+\d+\s+G\d+|LATITUDE\s+\d+|ELITEBOOK\s+\d+\s+G\d+|THINKPAD\s+[A-Z0-9]+|ELITEDESK\s+[A-Z0-9\s]+|MACBOOK\s+PRO|IPHONE\s+[0-9A-Z]+)\b/i', $title, $modelMatch)) {
            $model = strtoupper(trim($modelMatch[1]));
        }

        $sku = trim((string) $artCode);
        if ($sku === '' && preg_match('/INTERNO:\s*([^\n\r]+)/i', $text, $m)) {
            $sku = trim($m[1]);
        }
        $sku = trim($sku, " :,.-_");

        return [
            'title' => $title ?: 'Prodotto senza titolo',
            'brand' => $brand,
            'model' => $model,
            'sku'   => $sku,
        ];
    }

    /**
     * Resolve existing Product or create a new one.
     */
    private function resolveOrCreateProduct(Fornitore $fornitore, array $productInfo, float $unitPrice): Product
    {
        $sku = $productInfo['sku'];
        $title = $productInfo['title'];
        $brand = $productInfo['brand'];
        $model = $productInfo['model'];

        // 1. Search by Supplier SKU in ProductIdentifier
        if ($sku !== '') {
            $norm = preg_replace('/[^A-Za-z0-9]+/', '', strtoupper($sku));
            if ($norm !== '') {
                $existingByIdentifier = Product::query()
                    ->whereHas('identifiers', function ($q) use ($norm, $fornitore) {
                        $q->where('normalized_code', $norm)
                          ->where('fornitore_id', (int) $fornitore->id);
                    })
                    ->first();

                if ($existingByIdentifier instanceof Product) {
                    return $existingByIdentifier;
                }
            }
        }

        // 2. Search by Canonical Key or exact Name
        $canonicalKey = Str::slug(($brand ? $brand . ' ' : '') . ($model ?: $title));
        $existing = Product::query()
            ->where('canonical_key', $canonicalKey)
            ->orWhere(function ($q) use ($title, $fornitore) {
                $q->where('name', $title)
                  ->where('default_fornitore_id', (int) $fornitore->id);
            })
            ->first();

        if ($existing instanceof Product) {
            return $existing;
        }

        // 3. Create new Product
        return Product::query()->create([
            'default_fornitore_id' => (int) $fornitore->id,
            'type'                 => 'product',
            'canonical_key'        => $canonicalKey,
            'name'                 => $title,
            'brand'                => $brand,
            'model'                => $model,
            'unit_measure'         => 'pz',
            'description'          => $title,
            'track_serials'        => true,
            'is_active'            => true,
            'meta'                 => [
                'source'          => 'contabilita_mysql',
                'prezzo_acquisto' => $unitPrice > 0 ? $unitPrice : null,
            ],
        ]);
    }
}