<?php

declare(strict_types=1);

namespace App\Services\Import;

use App\Models\CommonCatalogItem;
use App\Models\File;
use App\Services\FileService;
use Illuminate\Support\Facades\Storage;
use Illuminate\Support\Str;
use RuntimeException;

class ImportTechnicalDescriptionsService
{
    /**
     * @param list<array<string, mixed>> $sourceProducts
     * @return array<string, int|list<string>>
     */
    public function handle(
        array $sourceProducts,
        ?string $imagesDirectory,
        int $userId,
        bool $overwrite = false,
        bool $createMissing = false,
        bool $applyToVariants = false,
        bool $dryRun = false,
    ): array {
        $stats = [
            'source' => count($sourceProducts),
            'matched' => 0,
            'updated' => 0,
            'created' => 0,
            'unchanged' => 0,
            'missing' => 0,
            'ambiguous' => 0,
            'images_imported' => 0,
            'images_missing' => 0,
            'missing_articles' => [],
            'ambiguous_articles' => [],
        ];

        foreach ($sourceProducts as $source) {
            $article = trim((string) ($source['article'] ?? ''));
            if ($article === '') {
                continue;
            }

            $items = CommonCatalogItem::query()->where('article', $article)->get();
            if ($items->isEmpty()) {
                if (! $createMissing) {
                    $stats['missing']++;
                    $stats['missing_articles'][] = $article;
                    continue;
                }

                $items = collect([new CommonCatalogItem([
                    'article' => $article,
                    'calculator_name' => $this->nullableString($source['name'] ?? null),
                ])]);
            } elseif ($items->count() > 1 && ! $applyToVariants) {
                $stats['ambiguous']++;
                $stats['ambiguous_articles'][] = $article;
                continue;
            }

            foreach ($items as $item) {
                $stats['matched']++;
                $payload = $this->payload($source);
                $changes = $this->changes($item, $payload, $overwrite);
                $isNew = ! $item->exists;
                $imageSource = $this->imageSource($source, $imagesDirectory);
                $shouldImportImage = $item->image_file_id === null && $imageSource !== null;

                if ($dryRun) {
                    if ($isNew) {
                        $stats['created']++;
                    } elseif ($changes !== [] || $shouldImportImage) {
                        $stats['updated']++;
                    } else {
                        $stats['unchanged']++;
                    }
                    if ($shouldImportImage) {
                        $stats['images_imported']++;
                    } elseif ($item->image_file_id === null && ($source['image_path'] ?? '') !== '') {
                        $stats['images_missing']++;
                    }
                    continue;
                }

                if ($changes !== []) {
                    $item->fill($changes);
                }
                if ($isNew) {
                    $item->save();
                    $stats['created']++;
                } elseif ($item->isDirty()) {
                    $item->save();
                    $stats['updated']++;
                } else {
                    $stats['unchanged']++;
                }

                if ($item->image_file_id === null && ($source['image_path'] ?? '') !== '') {
                    if ($imageSource === null) {
                        $stats['images_missing']++;
                    } else {
                        $this->importImage($item, $imageSource, $userId);
                        $stats['images_imported']++;
                        if (! $isNew && $changes === []) {
                            $stats['unchanged']--;
                            $stats['updated']++;
                        }
                    }
                }
            }
        }

        $stats['missing_articles'] = array_values(array_unique($stats['missing_articles']));
        $stats['ambiguous_articles'] = array_values(array_unique($stats['ambiguous_articles']));

        return $stats;
    }

    /** @param array<string, mixed> $source */
    private function payload(array $source): array
    {
        return [
            'series' => $this->nullableString($source['series'] ?? null),
            'calculator_name' => $this->nullableString($source['name'] ?? null),
            'print_name' => $this->nullableString($source['name_for_form'] ?? null),
            'product_group' => $this->nullableString($source['product_group'] ?? null),
            'characteristics' => $this->nullableString($source['characteristics'] ?? null),
            'technical_description' => $this->nullableString($source['tech_description'] ?? null),
            'technical_description_short' => $this->nullableString($source['tech_description_short'] ?? null),
        ];
    }

    private function changes(CommonCatalogItem $item, array $payload, bool $overwrite): array
    {
        return array_filter(
            $payload,
            function (mixed $value, string $field) use ($item, $overwrite): bool {
                if ($value === null) {
                    return false;
                }

                return $overwrite || trim((string) $item->getAttribute($field)) === '';
            },
            ARRAY_FILTER_USE_BOTH,
        );
    }

    /** @param array<string, mixed> $source */
    private function imageSource(array $source, ?string $imagesDirectory): ?string
    {
        $imageName = basename(str_replace('\\', '/', (string) ($source['image_path'] ?? '')));
        if ($imageName === '' || $imagesDirectory === null || $imagesDirectory === '') {
            return null;
        }

        $path = rtrim($imagesDirectory, DIRECTORY_SEPARATOR).DIRECTORY_SEPARATOR.$imageName;

        return is_file($path) && is_readable($path) ? $path : null;
    }

    private function importImage(CommonCatalogItem $item, string $sourcePath, int $userId): void
    {
        $contents = file_get_contents($sourcePath);
        if (! is_string($contents) || $contents === '') {
            throw new RuntimeException("Не удалось прочитать изображение {$sourcePath}.");
        }

        $mimeType = (string) (new \finfo(FILEINFO_MIME_TYPE))->buffer($contents);
        $extension = match ($mimeType) {
            'image/jpeg' => 'jpg',
            'image/png' => 'png',
            'image/webp' => 'webp',
            default => throw new RuntimeException("Неподдерживаемый MIME-тип изображения {$mimeType}."),
        };
        $path = "common_catalog/items/{$item->id}/image/".Str::uuid().".{$extension}";
        if (! Storage::disk('public')->put($path, $contents)) {
            throw new RuntimeException("Не удалось сохранить изображение для артикула {$item->article}.");
        }

        $file = File::query()->create([
            'link' => url('/storage/'.$path),
            'path' => $path,
            'user_id' => $userId,
            'original_name' => basename($sourcePath),
            'mime_type' => $mimeType,
        ]);
        app(FileService::class)->ensureThumbnail($file);
        $item->update(['image_file_id' => $file->id]);
    }

    private function nullableString(mixed $value): ?string
    {
        $value = trim((string) $value);

        return $value === '' ? null : $value;
    }
}