<?php

namespace App\Services;

use App\Constants\SystemFields;
use App\Models\Commons\Category;
use App\Models\ItemMaster\ItemField;
use App\Models\Items\Item;
use App\Models\Items\ItemDetail;
use App\Models\Products\CommonCode;
use Illuminate\Contracts\Pagination\LengthAwarePaginator;
use Symfony\Component\HttpKernel\Exception\BadRequestHttpException;

class ItemService extends Service
{
    /**
     * items 테이블의 고정 컬럼 목록 조회 (SystemFields + ItemField 기반)
     */
    private function getKnownFields(): array
    {
        $tenantId = $this->tenantId();

        // 1. 기본 고정 필드
        $baseFields = [
            'id', 'tenant_id', 'item_type', 'code', 'name', 'unit', 'category_id',
            'bom', 'attributes', 'attributes_archive', 'options', 'description',
            'is_active', 'created_by', 'updated_by', 'deleted_by',
            'created_at', 'updated_at', 'deleted_at',
        ];

        // 2. ItemField에서 storage_type='column'인 필드의 field_key 조회
        $columnFields = ItemField::where('tenant_id', $tenantId)
            ->where('source_table', 'items')
            ->where('storage_type', 'column')
            ->whereNotNull('field_key')
            ->pluck('field_key')
            ->toArray();

        // 3. API 전용 필드
        $apiFields = ['type_code'];

        return array_unique(array_merge($baseFields, $columnFields, $apiFields));
    }

    /**
     * 정의된 필드 외의 동적 필드를 options로 추출
     */
    private function extractDynamicOptions(array $params): array
    {
        $knownFields = $this->getKnownFields();

        $dynamicOptions = [];
        foreach ($params as $key => $value) {
            if (! in_array($key, $knownFields) && $value !== null && $value !== '') {
                $dynamicOptions[$key] = $value;
            }
        }

        return $dynamicOptions;
    }

    /**
     * 기존 options 배열과 동적 필드를 병합
     */
    private function mergeOptionsWithDynamic($existingOptions, array $dynamicOptions): array
    {
        if (! is_array($existingOptions) || empty($existingOptions)) {
            return $dynamicOptions;
        }

        $isAssoc = array_keys($existingOptions) !== range(0, count($existingOptions) - 1);

        if ($isAssoc) {
            return array_merge($existingOptions, $dynamicOptions);
        }

        foreach ($dynamicOptions as $key => $value) {
            $existingOptions[] = ['label' => $key, 'value' => $value];
        }

        return $existingOptions;
    }

    /**
     * options 입력을 [{label, value, unit}] 형태로 정규화
     */
    private function normalizeOptions(?array $in): ?array
    {
        if (! $in) {
            return null;
        }

        $isAssoc = array_keys($in) !== range(0, count($in) - 1);

        if ($isAssoc) {
            $out = [];
            foreach ($in as $k => $v) {
                $label = trim((string) $k);
                $value = is_scalar($v) ? trim((string) $v) : json_encode($v, JSON_UNESCAPED_UNICODE);
                if ($label !== '' || $value !== '') {
                    $out[] = ['label' => $label, 'value' => $value, 'unit' => ''];
                }
            }

            return $out ?: null;
        }

        $out = [];
        foreach ($in as $a) {
            if (! is_array($a)) {
                continue;
            }
            $label = trim((string) ($a['label'] ?? ''));
            $value = trim((string) ($a['value'] ?? ''));
            $unit = trim((string) ($a['unit'] ?? ''));

            if ($label === '' && $value === '') {
                continue;
            }

            $out[] = ['label' => $label, 'value' => $value, 'unit' => $unit];
        }

        return $out ?: null;
    }

    /**
     * 카테고리 트리 전체 조회
     */
    public function getCategory($request)
    {
        $parentId = $request->parentId ?? null;

        return $this->fetchCategoryTree($parentId);
    }

    /**
     * 내부 재귀 함수 (하위 카테고리 트리 구조로 구성)
     */
    protected function fetchCategoryTree(?int $parentId = null)
    {
        $tenantId = $this->tenantId();

        $query = Category::query()
            ->when($tenantId, fn ($q) => $q->where('tenant_id', $tenantId))
            ->when(
                is_null($parentId),
                fn ($q) => $q->whereNull('parent_id'),
                fn ($q) => $q->where('parent_id', $parentId)
            )
            ->where('is_active', 1)
            ->orderBy('sort_order');

        $categories = $query->get();

        foreach ($categories as $category) {
            $children = $this->fetchCategoryTree($category->id);
            $category->setRelation('children', $children);
        }

        return $categories;
    }

    /**
     * 목록/검색
     */
    public function index(array $params): LengthAwarePaginator
    {
        $tenantId = $this->tenantId();

        $size = (int) ($params['size'] ?? $params['per_page'] ?? 20);
        $q = trim((string) ($params['q'] ?? $params['search'] ?? ''));
        $categoryId = $params['category_id'] ?? null;
        $itemType = $params['item_type'] ?? null;
        $active = $params['active'] ?? null;

        $query = Item::query()
            ->with(['category:id,name', 'details'])
            ->where('tenant_id', $tenantId);

        // 검색어
        if ($q !== '') {
            $query->where(function ($w) use ($q) {
                $w->where('name', 'like', "%{$q}%")
                    ->orWhere('code', 'like', "%{$q}%")
                    ->orWhere('description', 'like', "%{$q}%");
            });
        }

        // 카테고리
        if ($categoryId) {
            $query->where('category_id', (int) $categoryId);
        }

        // item_type 필터
        if ($itemType) {
            $query->where('item_type', strtoupper($itemType));
        }

        // 활성 상태
        if ($active !== null && $active !== '') {
            $query->where('is_active', (bool) $active);
        }

        $paginator = $query->orderBy('id')->paginate($size);

        // 날짜 형식 변환
        $paginator->setCollection(
            $paginator->getCollection()->transform(function ($item) {
                $arr = $item->toArray();
                $arr['created_at'] = $item->created_at
                    ? $item->created_at->format('Y-m-d')
                    : null;

                return $arr;
            })
        );

        return $paginator;
    }

    /**
     * 생성
     */
    public function store(array $data): Item
    {
        $tenantId = $this->tenantId();
        $userId = $this->apiUserId();

        // 동적 필드를 options에 병합
        $dynamicOptions = $this->extractDynamicOptions($data);
        if (! empty($dynamicOptions)) {
            $existingOptions = $data['options'] ?? [];
            $data['options'] = $this->mergeOptionsWithDynamic($existingOptions, $dynamicOptions);
        }

        // options 정규화
        if (isset($data['options'])) {
            $data['options'] = $this->normalizeOptions($data['options']);
        }

        // tenant별 code 유니크 체크
        $dup = Item::query()
            ->where('tenant_id', $tenantId)
            ->where('code', $data['code'])
            ->exists();
        if ($dup) {
            throw new BadRequestHttpException(__('error.duplicate_key'));
        }

        // items 테이블 데이터
        $itemData = [
            'tenant_id' => $tenantId,
            'item_type' => strtoupper($data['item_type']),
            'code' => $data['code'],
            'name' => $data['name'],
            'unit' => $data['unit'] ?? null,
            'category_id' => $data['category_id'] ?? null,
            'bom' => $data['bom'] ?? null,
            'attributes' => $data['attributes'] ?? null,
            'options' => $data['options'] ?? null,
            'description' => $data['description'] ?? null,
            'is_active' => $data['is_active'] ?? true,
            'created_by' => $userId,
        ];

        $item = Item::create($itemData);

        // item_details 테이블 데이터
        $detailData = $this->extractDetailData($data);
        $detailData['item_id'] = $item->id;
        ItemDetail::create($detailData);

        return $item->load('details');
    }

    /**
     * 단건 조회
     */
    public function show(int $id): Item
    {
        $tenantId = $this->tenantId();

        $item = Item::query()
            ->with(['category:id,name', 'details'])
            ->where('tenant_id', $tenantId)
            ->find($id);

        if (! $item) {
            throw new BadRequestHttpException(__('error.not_found'));
        }

        return $item;
    }

    /**
     * 수정
     */
    public function update(int $id, array $data): Item
    {
        $tenantId = $this->tenantId();
        $userId = $this->apiUserId();

        $item = Item::query()->where('tenant_id', $tenantId)->find($id);
        if (! $item) {
            throw new BadRequestHttpException(__('error.not_found'));
        }

        // 동적 필드를 options에 병합
        $dynamicOptions = $this->extractDynamicOptions($data);
        if (! empty($dynamicOptions)) {
            $existingOptions = $data['options'] ?? [];
            $data['options'] = $this->mergeOptionsWithDynamic($existingOptions, $dynamicOptions);
        }

        // options 정규화
        if (isset($data['options'])) {
            $data['options'] = $this->normalizeOptions($data['options']);
        }

        // code 변경 시 중복 체크
        if (isset($data['code']) && $data['code'] !== $item->code) {
            $dup = Item::query()
                ->where('tenant_id', $tenantId)
                ->where('code', $data['code'])
                ->exists();
            if ($dup) {
                throw new BadRequestHttpException(__('error.duplicate_key'));
            }
        }

        // items 테이블 업데이트
        $itemData = array_intersect_key($data, array_flip([
            'item_type', 'code', 'name', 'unit', 'category_id',
            'bom', 'attributes', 'options', 'description', 'is_active',
        ]));
        $itemData['updated_by'] = $userId;

        if (isset($itemData['item_type'])) {
            $itemData['item_type'] = strtoupper($itemData['item_type']);
        }

        $item->update($itemData);

        // item_details 테이블 업데이트
        $detailData = $this->extractDetailData($data);
        if (! empty($detailData)) {
            $item->details()->updateOrCreate(
                ['item_id' => $item->id],
                $detailData
            );
        }

        return $item->load('details')->refresh();
    }

    /**
     * 삭제 (soft delete)
     */
    public function destroy(int $id): void
    {
        $tenantId = $this->tenantId();

        $item = Item::query()->where('tenant_id', $tenantId)->find($id);
        if (! $item) {
            throw new BadRequestHttpException(__('error.not_found'));
        }

        $item->delete();
    }

    /**
     * 간편 검색 (모달/드롭다운)
     */
    public function search(array $params)
    {
        $tenantId = $this->tenantId();
        $q = trim((string) ($params['q'] ?? ''));
        $limit = (int) ($params['limit'] ?? 20);
        $itemType = $params['item_type'] ?? null;

        $query = Item::query()->where('tenant_id', $tenantId);

        if ($q !== '') {
            $query->where(function ($w) use ($q) {
                $w->where('name', 'like', "%{$q}%")
                    ->orWhere('code', 'like', "%{$q}%");
            });
        }

        if ($itemType) {
            $query->where('item_type', strtoupper($itemType));
        }

        return $query->orderBy('name')
            ->limit($limit)
            ->get(['id', 'code', 'name', 'item_type', 'category_id']);
    }

    /**
     * 활성/비활성 토글
     */
    public function toggle(int $id): array
    {
        $tenantId = $this->tenantId();
        $userId = $this->apiUserId();

        $item = Item::query()->where('tenant_id', $tenantId)->find($id);
        if (! $item) {
            throw new BadRequestHttpException(__('error.not_found'));
        }

        $item->is_active = ! $item->is_active;
        $item->updated_by = $userId;
        $item->save();

        return ['id' => $item->id, 'is_active' => $item->is_active];
    }

    /**
     * item_details 데이터 추출
     */
    private function extractDetailData(array $data): array
    {
        $detailFields = [
            // Products 전용
            'is_sellable', 'is_purchasable', 'is_producible',
            'safety_stock', 'lead_time', 'is_variable_size',
            'product_category', 'part_type',
            'bending_diagram', 'bending_details',
            'specification_file', 'specification_file_name',
            'certification_file', 'certification_file_name',
            'certification_number', 'certification_start_date', 'certification_end_date',
            // Materials 전용
            'is_inspection', 'item_name', 'specification', 'search_tag', 'remarks',
        ];

        return array_intersect_key($data, array_flip($detailFields));
    }
}