<?php

namespace App\Domains\Desfile\Services;

use App\Domains\Attachable\Models\Attachment;
use App\Domains\Attachable\Services\AttachmentService;
use App\Domains\Catalog\Models\CatalogItem;
use App\Domains\Catalog\Models\Inventory;
use App\Domains\Catalog\Models\ItemAttribute;
use App\Domains\Catalog\Models\Variant;
use App\Domains\Tenant\Models\Tenant;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Http\UploadedFile;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Str;
use Illuminate\Validation\ValidationException;
use Throwable;

class EntryService
{
    private const ATTRIBUTE_MAP = [
        'type' => 'tipo',
        'sector' => 'sector',
        'row' => 'fila',
        'seat' => 'asiento',
    ];

    public function __construct(private readonly AttachmentService $attachmentService) {}

    public function current(Tenant $tenant): CatalogItem
    {
        return $this->entryQuery($tenant)
            ->with([
                'allAttachments',
                'itemAttributes.attribute.options',
                'variants' => fn ($query) => $query->orderBy('id'),
                'variants.inventory',
                'variants.definitions.itemAttribute.attribute',
            ])
            ->firstOrFail();
    }

    /**
     * @param  array<int, array<string, mixed>>  $variants
     */
    public function syncVariants(Tenant $tenant, array $variants): CatalogItem
    {
        DB::transaction(function () use ($tenant, $variants): void {
            $entry = $this->entryQuery($tenant)->lockForUpdate()->firstOrFail();
            $itemAttributes = $this->itemAttributes($entry);
            $existingVariants = $entry->variants()
                ->with(['inventory', 'definitions.itemAttribute.attribute'])
                ->lockForUpdate()
                ->get();
            $incomingIds = collect($variants)
                ->pluck('id')
                ->filter()
                ->map(fn ($id): int => (int) $id)
                ->values();

            foreach ($existingVariants->whereNotIn('id', $incomingIds) as $variant) {
                $this->assertVariantCanChangeIdentity($variant, 'variants');
                $variant->delete();
            }

            foreach (array_values($variants) as $index => $data) {
                $values = $this->resolveValues($itemAttributes, $data, $index);
                $variant = isset($data['id'])
                    ? $existingVariants->firstWhere('id', (int) $data['id'])
                    : null;

                if (isset($data['id']) && $variant === null) {
                    throw ValidationException::withMessages([
                        "variants.{$index}.id" => [
                            'La variante no pertenece al producto Entrada del desfile.',
                        ],
                    ]);
                }

                if ($variant === null) {
                    $variant = $entry->variants()->create([
                        'inventory_id' => Inventory::query()->create(['real_stock' => 1])->id,
                        'descripcion' => $this->description($values),
                        'precio' => $data['price'],
                    ]);
                } else {
                    if ($this->identityChanged($variant, $values)) {
                        $this->assertVariantCanChangeIdentity($variant, "variants.{$index}");
                    }

                    $variant->update([
                        'descripcion' => $this->description($values),
                        'precio' => $data['price'],
                    ]);
                    $variant->definitions()->delete();
                }

                $variant->definitions()->createMany(
                    collect($values)->map(
                        fn (string $value, string $code): array => [
                            'item_attribute_id' => $itemAttributes[$code]->id,
                            'value' => $value,
                        ],
                    )->values()->all(),
                );
            }

            $minimumPrice = $entry->variants()->min('precio');
            if ($minimumPrice !== null) {
                $entry->update(['precio' => $minimumPrice]);
            }
        });

        return $this->current($tenant);
    }

    public function replaceImage(
        Tenant $tenant,
        UploadedFile $image,
        bool $isEnabled,
    ): CatalogItem {
        $attachment = $this->attachmentService->store($image, 'catalog-items');
        $previousAttachments = collect();

        try {
            DB::transaction(function () use ($tenant, $attachment, $isEnabled, &$previousAttachments): void {
                $entry = $this->entryQuery($tenant)->lockForUpdate()->firstOrFail();
                $previousAttachments = $entry->allAttachments()->get();
                $entry->allAttachments()->sync([
                    $attachment->id => [
                        'orden' => 0,
                        'is_enabled' => $isEnabled,
                    ],
                ]);
            });
        } catch (Throwable $throwable) {
            $this->deleteAttachmentQuietly($attachment);
            throw $throwable;
        }

        $previousAttachments->each(fn (Attachment $previous) => $this->deleteIfUnused($previous));

        return $this->current($tenant);
    }

    public function updateImage(Tenant $tenant, bool $isEnabled): CatalogItem
    {
        DB::transaction(function () use ($tenant, $isEnabled): void {
            $entry = $this->entryQuery($tenant)->lockForUpdate()->firstOrFail();
            $attachment = $entry->allAttachments()->lockForUpdate()->firstOrFail();

            $entry->allAttachments()->updateExistingPivot($attachment->id, [
                'is_enabled' => $isEnabled,
            ]);
        });

        return $this->current($tenant);
    }

    public function deleteImage(Tenant $tenant): void
    {
        $attachment = DB::transaction(function () use ($tenant): Attachment {
            $entry = $this->entryQuery($tenant)->lockForUpdate()->firstOrFail();
            $attachment = $entry->allAttachments()->lockForUpdate()->firstOrFail();
            $entry->allAttachments()->detach($attachment->id);

            return $attachment;
        });

        $this->deleteIfUnused($attachment);
    }

    /** @return Collection<string, ItemAttribute> */
    private function itemAttributes(CatalogItem $entry): Collection
    {
        $attributes = $entry->itemAttributes()
            ->with('attribute.options')
            ->get()
            ->filter(fn (ItemAttribute $itemAttribute): bool => $itemAttribute->attribute !== null)
            ->keyBy(fn (ItemAttribute $itemAttribute): string => $itemAttribute->attribute->codigo);
        $missing = collect(self::ATTRIBUTE_MAP)->diff($attributes->keys());

        if ($missing->isNotEmpty()) {
            throw ValidationException::withMessages([
                'variants' => [
                    'Faltan atributos requeridos para las entradas del desfile: '.$missing->implode(', ').'.',
                ],
            ]);
        }

        return $attributes;
    }

    /**
     * @param  Collection<string, ItemAttribute>  $itemAttributes
     * @param  array<string, mixed>  $data
     * @return array<string, string>
     */
    private function resolveValues(Collection $itemAttributes, array $data, int $index): array
    {
        $values = [];

        foreach (self::ATTRIBUTE_MAP as $input => $code) {
            $requestedValue = trim((string) $data[$input]);
            $option = $itemAttributes[$code]->attribute->options->first(
                fn ($candidate): bool => $this->normalize($candidate->value) === $this->normalize($requestedValue),
            );

            if ($option === null) {
                throw ValidationException::withMessages([
                    "variants.{$index}.{$input}" => ['La opción seleccionada no es válida.'],
                ]);
            }

            $values[$code] = $option->value;
        }

        return $values;
    }

    /** @param array<string, string> $values */
    private function identityChanged(Variant $variant, array $values): bool
    {
        $currentValues = $variant->definitions
            ->mapWithKeys(fn ($definition): array => [
                $definition->itemAttribute?->attribute?->codigo => $definition->value,
            ]);

        return collect($values)->contains(
            fn (string $value, string $code): bool => $this->normalize((string) $currentValues->get($code))
                !== $this->normalize($value),
        );
    }

    private function assertVariantCanChangeIdentity(Variant $variant, string $key): void
    {
        $inventory = $variant->inventory;

        if (($inventory?->reserved_stock ?? 0) > 0 || ($inventory?->sold_units ?? 0) > 0) {
            throw ValidationException::withMessages([
                $key => [
                    'No se puede modificar ni eliminar un asiento con ventas o reservas.',
                ],
            ]);
        }
    }

    /** @param array<string, string> $values */
    private function description(array $values): string
    {
        return "Sector {$values['sector']} - Fila {$values['fila']} - Asiento {$values['asiento']} - {$values['tipo']}";
    }

    private function normalize(string $value): string
    {
        return Str::ascii(mb_strtolower(trim($value)));
    }

    /** @return Builder<CatalogItem> */
    private function entryQuery(Tenant $tenant): Builder
    {
        return CatalogItem::query()
            ->where('tenant_code', $tenant->codigo)
            ->where('slug', 'entrada');
    }

    private function deleteIfUnused(Attachment $attachment): void
    {
        if (DB::table('catalog_items_attachments')->where('attachment_id', $attachment->id)->exists()) {
            return;
        }

        $this->deleteAttachmentQuietly($attachment);
    }

    private function deleteAttachmentQuietly(Attachment $attachment): void
    {
        try {
            $this->attachmentService->delete($attachment);
        } catch (Throwable $throwable) {
            report($throwable);
        }
    }
}