<?php

namespace App\Services\ItemMaster;

use App\Models\ItemMaster\EntityRelationship;
use App\Models\ItemMaster\ItemBomItem;
use App\Models\ItemMaster\ItemField;
use App\Models\ItemMaster\ItemSection;
use App\Services\Service;
use Illuminate\Database\Eloquent\Collection;
use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;

class ItemSectionService extends Service
{
    /**
     * 독립 섹션 목록 조회
     *
     * GET /api/v1/item-master/sections
     */
    public function index(?bool $isTemplate = null): Collection
    {
        $tenantId = $this->tenantId();

        $query = ItemSection::where('tenant_id', $tenantId)
            ->with(['fields', 'bomItems']);

        if ($isTemplate === true) {
            $query->templates();
        } elseif ($isTemplate === false) {
            $query->nonTemplates();
        }

        return $query->orderBy('created_at', 'desc')->get();
    }

    /**
     * 독립 섹션 생성 (페이지 연결 없음)
     *
     * POST /api/v1/item-master/sections
     */
    public function storeIndependent(array $data): ItemSection
    {
        $tenantId = $this->tenantId();
        $userId = $this->apiUserId();

        $section = ItemSection::create([
            'tenant_id' => $tenantId,
            'group_id' => $data['group_id'] ?? 1,
            'page_id' => null,
            'title' => $data['title'],
            'type' => $data['type'],
            'order_no' => 0,
            'is_template' => $data['is_template'] ?? false,
            'is_default' => $data['is_default'] ?? false,
            'description' => $data['description'] ?? null,
            'created_by' => $userId,
        ]);

        return $section->load(['fields', 'bomItems']);
    }

    /**
     * 섹션 복제
     *
     * POST /api/v1/item-master/sections/{id}/clone
     */
    public function clone(int $id): ItemSection
    {
        $tenantId = $this->tenantId();
        $userId = $this->apiUserId();

        $original = ItemSection::where('tenant_id', $tenantId)
            ->where('id', $id)
            ->with(['fields', 'bomItems'])
            ->first();

        if (! $original) {
            throw new NotFoundHttpException(__('error.section_not_found'));
        }

        // 섹션 복제
        $cloned = ItemSection::create([
            'tenant_id' => $tenantId,
            'group_id' => $original->group_id,
            'page_id' => null,
            'title' => $original->title.' (복사본)',
            'type' => $original->type,
            'order_no' => 0,
            'is_template' => $original->is_template,
            'is_default' => false,
            'description' => $original->description,
            'created_by' => $userId,
        ]);

        // 필드 복제
        foreach ($original->fields as $field) {
            ItemField::create([
                'tenant_id' => $tenantId,
                'group_id' => $field->group_id,
                'section_id' => $cloned->id,
                'field_name' => $field->field_name,
                'field_type' => $field->field_type,
                'order_no' => $field->order_no,
                'is_required' => $field->is_required,
                'default_value' => $field->default_value,
                'placeholder' => $field->placeholder,
                'display_condition' => $field->display_condition,
                'validation_rules' => $field->validation_rules,
                'options' => $field->options,
                'properties' => $field->properties,
                'created_by' => $userId,
            ]);
        }

        // BOM 항목 복제
        foreach ($original->bomItems as $bom) {
            ItemBomItem::create([
                'tenant_id' => $tenantId,
                'group_id' => $bom->group_id,
                'section_id' => $cloned->id,
                'item_code' => $bom->item_code,
                'item_name' => $bom->item_name,
                'quantity' => $bom->quantity,
                'unit' => $bom->unit,
                'unit_price' => $bom->unit_price,
                'total_price' => $bom->total_price,
                'spec' => $bom->spec,
                'note' => $bom->note,
                'created_by' => $userId,
            ]);
        }

        return $cloned->load(['fields', 'bomItems']);
    }

    /**
     * 섹션 사용처 조회 (어떤 페이지에 연결되어 있는지)
     *
     * GET /api/v1/item-master/sections/{id}/usage
     */
    public function getUsage(int $id): array
    {
        $tenantId = $this->tenantId();

        $section = ItemSection::where('tenant_id', $tenantId)
            ->where('id', $id)
            ->first();

        if (! $section) {
            throw new NotFoundHttpException(__('error.section_not_found'));
        }

        // 1. 기존 FK 기반 연결 (page_id)
        $directPage = $section->page;

        // 2. entity_relationships 기반 연결
        $linkedPageIds = EntityRelationship::where('child_type', EntityRelationship::TYPE_SECTION)
            ->where('child_id', $id)
            ->where('parent_type', EntityRelationship::TYPE_PAGE)
            ->pluck('parent_id')
            ->toArray();

        return [
            'section_id' => $id,
            'direct_page' => $directPage,
            'linked_pages' => $section->linkedPages()->get(),
            'total_usage_count' => ($directPage ? 1 : 0) + count($linkedPageIds),
        ];
    }

    /**
     * 섹션 생성
     */
    public function store(int $pageId, array $data): ItemSection
    {
        $tenantId = $this->tenantId();
        $userId = $this->apiUserId();

        // order_no 자동 계산 (해당 페이지의 마지막 섹션 + 1)
        $maxOrder = ItemSection::where('tenant_id', $tenantId)
            ->where('page_id', $pageId)
            ->max('order_no');

        $section = ItemSection::create([
            'tenant_id' => $tenantId,
            'page_id' => $pageId,
            'title' => $data['title'],
            'type' => $data['type'],
            'order_no' => ($maxOrder ?? -1) + 1,
            'created_by' => $userId,
        ]);

        $section->load(['fields', 'bomItems']);

        return $section;
    }

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

        $section = ItemSection::where('tenant_id', $tenantId)
            ->where('id', $id)
            ->first();

        if (! $section) {
            throw new NotFoundHttpException(__('error.not_found'));
        }

        $section->update([
            'title' => $data['title'] ?? $section->title,
            'updated_by' => $userId,
        ]);

        $section->load(['fields', 'bomItems']);

        return $section;
    }

    /**
     * 섹션 삭제 (Soft Delete)
     */
    public function destroy(int $id): void
    {
        $tenantId = $this->tenantId();
        $userId = $this->apiUserId();

        $section = ItemSection::where('tenant_id', $tenantId)
            ->where('id', $id)
            ->first();

        if (! $section) {
            throw new NotFoundHttpException(__('error.not_found'));
        }

        $section->update(['deleted_by' => $userId]);
        $section->delete();

        // Cascade: 하위 필드도 Soft Delete
        foreach ($section->fields as $field) {
            $field->update(['deleted_by' => $userId]);
            $field->delete();
        }

        foreach ($section->bomItems as $bomItem) {
            $bomItem->update(['deleted_by' => $userId]);
            $bomItem->delete();
        }
    }

    /**
     * 섹션 순서 변경
     *
     * @param  array  $items  [['id' => 1, 'order_no' => 0], ['id' => 2, 'order_no' => 1], ...]
     */
    public function reorder(int $pageId, array $items): void
    {
        $tenantId = $this->tenantId();
        $userId = $this->apiUserId();

        foreach ($items as $item) {
            ItemSection::where('tenant_id', $tenantId)
                ->where('page_id', $pageId)
                ->where('id', $item['id'])
                ->update([
                    'order_no' => $item['order_no'],
                    'updated_by' => $userId,
                ]);
        }
    }
}