<?php

namespace App\Services;

use App\Services\Service;
use Shared\Models\Products\ModelMaster;
use Shared\Models\Products\BomTemplate;
use Shared\Models\Products\BomTemplateItem;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\DB;

/**
 * BOM Resolver Service
 * 매개변수 기반 BOM 해석 및 생성 엔진
 */
class BomResolverService extends Service
{
    private ModelParameterService $parameterService;
    private ModelFormulaService $formulaService;
    private BomConditionRuleService $conditionRuleService;

    public function __construct()
    {
        parent::__construct();
        $this->parameterService = new ModelParameterService();
        $this->formulaService = new ModelFormulaService();
        $this->conditionRuleService = new BomConditionRuleService();
    }

    /**
     * 매개변수 기반 BOM 해석 (미리보기)
     */
    public function resolveBom(int $modelId, array $inputParameters): array
    {
        $this->validateModelAccess($modelId);

        // 1. 매개변수 검증 및 타입 변환
        $validatedParameters = $this->validateAndCastParameters($modelId, $inputParameters);

        // 2. 공식 계산
        $calculatedValues = $this->calculateFormulas($modelId, $validatedParameters);

        // 3. 기본 BOM 템플릿 가져오기
        $baseBomItems = $this->getBaseBomItems($modelId);

        // 4. 조건 규칙 적용
        $resolvedBomItems = $this->applyConditionRules($modelId, $baseBomItems, $calculatedValues);

        // 5. 수량 및 공식 계산 적용
        $finalBomItems = $this->calculateItemQuantities($resolvedBomItems, $calculatedValues);

        return [
            'model_id' => $modelId,
            'input_parameters' => $validatedParameters,
            'calculated_values' => $calculatedValues,
            'bom_items' => $finalBomItems,
            'summary' => $this->generateBomSummary($finalBomItems),
            'resolved_at' => now()->toISOString(),
        ];
    }

    /**
     * 실시간 미리보기 (캐시 활용)
     */
    public function previewBom(int $modelId, array $inputParameters): array
    {
        // 캐시 키 생성
        $cacheKey = $this->generateCacheKey($modelId, $inputParameters);

        return Cache::remember($cacheKey, 300, function () use ($modelId, $inputParameters) {
            return $this->resolveBom($modelId, $inputParameters);
        });
    }

    /**
     * BOM 검증 (오류 체크)
     */
    public function validateBom(int $modelId, array $inputParameters): array
    {
        $errors = [];
        $warnings = [];

        try {
            // 매개변수 검증
            $parameterErrors = $this->parameterService->validateParameterValues($modelId, $inputParameters);
            if (!empty($parameterErrors)) {
                $errors['parameters'] = $parameterErrors;
            }

            // 기본 BOM 템플릿 존재 확인
            if (!$this->hasBaseBomTemplate($modelId)) {
                $warnings[] = 'No base BOM template found for this model';
            }

            // 공식 계산 가능 여부 확인
            try {
                $validatedParameters = $this->validateAndCastParameters($modelId, $inputParameters);
                $this->calculateFormulas($modelId, $validatedParameters);
            } catch (\Throwable $e) {
                $errors['formulas'] = ['Formula calculation failed: ' . $e->getMessage()];
            }

            // 조건 규칙 평가 가능 여부 확인
            try {
                $calculatedValues = $this->calculateFormulas($modelId, $validatedParameters ?? []);
                $this->conditionRuleService->getApplicableRules($modelId, $calculatedValues);
            } catch (\Throwable $e) {
                $errors['condition_rules'] = ['Condition rule evaluation failed: ' . $e->getMessage()];
            }

        } catch (\Throwable $e) {
            $errors['general'] = [$e->getMessage()];
        }

        return [
            'valid' => empty($errors),
            'errors' => $errors,
            'warnings' => $warnings,
        ];
    }

    /**
     * BOM 비교 (다른 매개변수값과 비교)
     */
    public function compareBom(int $modelId, array $parameters1, array $parameters2): array
    {
        $bom1 = $this->resolveBom($modelId, $parameters1);
        $bom2 = $this->resolveBom($modelId, $parameters2);

        return [
            'parameters_diff' => $this->compareParameters($bom1['calculated_values'], $bom2['calculated_values']),
            'bom_items_diff' => $this->compareBomItems($bom1['bom_items'], $bom2['bom_items']),
            'summary_diff' => $this->compareSummary($bom1['summary'], $bom2['summary']),
        ];
    }

    /**
     * 대량 BOM 해석 (여러 매개변수 조합)
     */
    public function resolveBomBatch(int $modelId, array $parameterSets): array
    {
        $results = [];

        DB::transaction(function () use ($modelId, $parameterSets, &$results) {
            foreach ($parameterSets as $index => $parameters) {
                try {
                    $results[$index] = $this->resolveBom($modelId, $parameters);
                } catch (\Throwable $e) {
                    $results[$index] = [
                        'error' => $e->getMessage(),
                        'parameters' => $parameters,
                    ];
                }
            }
        });

        return $results;
    }

    /**
     * BOM 성능 최적화 제안
     */
    public function getOptimizationSuggestions(int $modelId, array $inputParameters): array
    {
        $resolvedBom = $this->resolveBom($modelId, $inputParameters);
        $suggestions = [];

        // 1. 불필요한 조건 규칙 탐지
        $unusedRules = $this->findUnusedRules($modelId, $resolvedBom['calculated_values']);
        if (!empty($unusedRules)) {
            $suggestions[] = [
                'type' => 'unused_rules',
                'message' => 'Found unused condition rules that could be removed',
                'details' => $unusedRules,
            ];
        }

        // 2. 복잡한 공식 탐지
        $complexFormulas = $this->findComplexFormulas($modelId);
        if (!empty($complexFormulas)) {
            $suggestions[] = [
                'type' => 'complex_formulas',
                'message' => 'Found complex formulas that might impact performance',
                'details' => $complexFormulas,
            ];
        }

        // 3. 중복 BOM 아이템 탐지
        $duplicateItems = $this->findDuplicateBomItems($resolvedBom['bom_items']);
        if (!empty($duplicateItems)) {
            $suggestions[] = [
                'type' => 'duplicate_items',
                'message' => 'Found duplicate BOM items that could be consolidated',
                'details' => $duplicateItems,
            ];
        }

        return $suggestions;
    }

    /**
     * 매개변수 검증 및 타입 변환
     */
    private function validateAndCastParameters(int $modelId, array $inputParameters): array
    {
        $errors = $this->parameterService->validateParameterValues($modelId, $inputParameters);

        if (!empty($errors)) {
            throw new \InvalidArgumentException(__('error.invalid_parameters') . ': ' . json_encode($errors));
        }

        return $this->parameterService->castParameterValues($modelId, $inputParameters);
    }

    /**
     * 공식 계산
     */
    private function calculateFormulas(int $modelId, array $parameters): array
    {
        return $this->formulaService->calculateFormulas($modelId, $parameters);
    }

    /**
     * 기본 BOM 템플릿 아이템 가져오기
     */
    private function getBaseBomItems(int $modelId): array
    {
        $model = ModelMaster::where('tenant_id', $this->tenantId())
            ->findOrFail($modelId);

        // 현재 활성 버전의 BOM 템플릿 가져오기
        $bomTemplate = BomTemplate::where('tenant_id', $this->tenantId())
            ->where('model_id', $modelId)
            ->where('is_active', true)
            ->orderBy('created_at', 'desc')
            ->first();

        if (!$bomTemplate) {
            return [];
        }

        $bomItems = BomTemplateItem::where('tenant_id', $this->tenantId())
            ->where('bom_template_id', $bomTemplate->id)
            ->orderBy('order')
            ->get()
            ->map(function ($item) {
                return [
                    'id' => $item->id,
                    'product_id' => $item->product_id,
                    'material_id' => $item->material_id,
                    'ref_type' => $item->ref_type,
                    'quantity' => $item->quantity,
                    'quantity_formula' => $item->quantity_formula,
                    'waste_rate' => $item->waste_rate,
                    'unit' => $item->unit,
                    'memo' => $item->memo,
                    'order' => $item->order,
                ];
            })
            ->toArray();

        return $bomItems;
    }

    /**
     * 조건 규칙 적용
     */
    private function applyConditionRules(int $modelId, array $bomItems, array $calculatedValues): array
    {
        return $this->conditionRuleService->applyRulesToBomItems($modelId, $bomItems, $calculatedValues);
    }

    /**
     * 아이템별 수량 계산
     */
    private function calculateItemQuantities(array $bomItems, array $calculatedValues): array
    {
        foreach ($bomItems as &$item) {
            // 수량 공식이 있는 경우 계산
            if (!empty($item['quantity_formula'])) {
                $calculatedQuantity = $this->evaluateQuantityFormula($item['quantity_formula'], $calculatedValues);
                if ($calculatedQuantity !== null) {
                    $item['calculated_quantity'] = $calculatedQuantity;
                }
            } else {
                $item['calculated_quantity'] = $item['quantity'] ?? 1;
            }

            // 낭비율 적용
            if (isset($item['waste_rate']) && $item['waste_rate'] > 0) {
                $item['total_quantity'] = $item['calculated_quantity'] * (1 + $item['waste_rate'] / 100);
            } else {
                $item['total_quantity'] = $item['calculated_quantity'];
            }

            // 반올림 (소수점 3자리)
            $item['calculated_quantity'] = round($item['calculated_quantity'], 3);
            $item['total_quantity'] = round($item['total_quantity'], 3);
        }

        return $bomItems;
    }

    /**
     * 수량 공식 계산
     */
    private function evaluateQuantityFormula(string $formula, array $variables): ?float
    {
        try {
            $expression = $formula;

            // 변수값 치환
            foreach ($variables as $name => $value) {
                if (is_numeric($value)) {
                    $expression = preg_replace('/\b' . preg_quote($name, '/') . '\b/', $value, $expression);
                }
            }

            // 안전한 계산 실행
            if (preg_match('/^[0-9+\-*\/().,\s]+$/', $expression)) {
                return eval("return $expression;");
            }

            return null;
        } catch (\Throwable $e) {
            return null;
        }
    }

    /**
     * BOM 요약 정보 생성
     */
    private function generateBomSummary(array $bomItems): array
    {
        $summary = [
            'total_items' => count($bomItems),
            'materials_count' => 0,
            'products_count' => 0,
            'total_cost' => 0, // 향후 가격 정보 추가 시
        ];

        foreach ($bomItems as $item) {
            if (!empty($item['material_id'])) {
                $summary['materials_count']++;
            } else {
                $summary['products_count']++;
            }
        }

        return $summary;
    }

    /**
     * 캐시 키 생성
     */
    private function generateCacheKey(int $modelId, array $parameters): string
    {
        ksort($parameters); // 매개변수 순서 정규화
        $hash = md5(json_encode($parameters));
        return "bom_preview_{$this->tenantId()}_{$modelId}_{$hash}";
    }

    /**
     * 기본 BOM 템플릿 존재 여부 확인
     */
    private function hasBaseBomTemplate(int $modelId): bool
    {
        return BomTemplate::where('tenant_id', $this->tenantId())
            ->where('model_id', $modelId)
            ->where('is_active', true)
            ->exists();
    }

    /**
     * 모델 접근 권한 검증
     */
    private function validateModelAccess(int $modelId): void
    {
        $model = ModelMaster::where('tenant_id', $this->tenantId())
            ->findOrFail($modelId);
    }

    /**
     * 매개변수 비교
     */
    private function compareParameters(array $params1, array $params2): array
    {
        $diff = [];

        $allKeys = array_unique(array_merge(array_keys($params1), array_keys($params2)));

        foreach ($allKeys as $key) {
            $value1 = $params1[$key] ?? null;
            $value2 = $params2[$key] ?? null;

            if ($value1 !== $value2) {
                $diff[$key] = [
                    'set1' => $value1,
                    'set2' => $value2,
                ];
            }
        }

        return $diff;
    }

    /**
     * BOM 아이템 비교
     */
    private function compareBomItems(array $items1, array $items2): array
    {
        // 간단한 비교 로직 (실제로는 더 정교한 비교 필요)
        return [
            'count_diff' => count($items1) - count($items2),
            'items_only_in_set1' => array_diff_key($items1, $items2),
            'items_only_in_set2' => array_diff_key($items2, $items1),
        ];
    }

    /**
     * 요약 정보 비교
     */
    private function compareSummary(array $summary1, array $summary2): array
    {
        $diff = [];

        foreach ($summary1 as $key => $value) {
            if (isset($summary2[$key]) && $value !== $summary2[$key]) {
                $diff[$key] = [
                    'set1' => $value,
                    'set2' => $summary2[$key],
                    'diff' => $value - $summary2[$key],
                ];
            }
        }

        return $diff;
    }

    /**
     * 사용되지 않는 규칙 찾기
     */
    private function findUnusedRules(int $modelId, array $calculatedValues): array
    {
        $allRules = $this->conditionRuleService->getRulesByModel($modelId);
        $applicableRules = $this->conditionRuleService->getApplicableRules($modelId, $calculatedValues);

        $unusedRules = $allRules->diff($applicableRules);

        return $unusedRules->map(function ($rule) {
            return [
                'id' => $rule->id,
                'name' => $rule->name,
                'condition' => $rule->condition_expression,
            ];
        })->toArray();
    }

    /**
     * 복잡한 공식 찾기
     */
    private function findComplexFormulas(int $modelId): array
    {
        $formulas = $this->formulaService->getFormulasByModel($modelId);

        return $formulas->filter(function ($formula) {
            // 복잡성 기준 (의존성 수, 표현식 길이 등)
            $dependencyCount = count($formula->dependencies ?? []);
            $expressionLength = strlen($formula->expression);

            return $dependencyCount > 5 || $expressionLength > 100;
        })->map(function ($formula) {
            return [
                'id' => $formula->id,
                'name' => $formula->name,
                'complexity_score' => strlen($formula->expression) + count($formula->dependencies ?? []) * 10,
            ];
        })->toArray();
    }

    /**
     * 중복 BOM 아이템 찾기
     */
    private function findDuplicateBomItems(array $bomItems): array
    {
        $seen = [];
        $duplicates = [];

        foreach ($bomItems as $item) {
            $key = ($item['product_id'] ?? 'null') . '_' . ($item['material_id'] ?? 'null');

            if (isset($seen[$key])) {
                $duplicates[] = [
                    'product_id' => $item['product_id'],
                    'material_id' => $item['material_id'],
                    'occurrences' => ++$seen[$key],
                ];
            } else {
                $seen[$key] = 1;
            }
        }

        return $duplicates;
    }
}