<?php

namespace App\Services;

use App\Services\Service;
use Shared\Models\Products\BomConditionRule;
use Shared\Models\Products\ModelMaster;
use Illuminate\Database\Eloquent\Collection;
use Illuminate\Pagination\LengthAwarePaginator;

/**
 * BOM Condition Rule Service
 * BOM 조건 규칙 관리 서비스
 */
class BomConditionRuleService extends Service
{
    /**
     * 모델별 조건 규칙 목록 조회
     */
    public function getRulesByModel(int $modelId, bool $paginate = false, int $perPage = 15): Collection|LengthAwarePaginator
    {
        $this->validateModelAccess($modelId);

        $query = BomConditionRule::where('model_id', $modelId)
            ->active()
            ->byPriority()
            ->with('model');

        if ($paginate) {
            return $query->paginate($perPage);
        }

        return $query->get();
    }

    /**
     * 조건 규칙 상세 조회
     */
    public function getRule(int $id): BomConditionRule
    {
        $rule = BomConditionRule::where('tenant_id', $this->tenantId())
            ->findOrFail($id);

        $this->validateModelAccess($rule->model_id);

        return $rule;
    }

    /**
     * 조건 규칙 생성
     */
    public function createRule(array $data): BomConditionRule
    {
        $this->validateModelAccess($data['model_id']);

        // 기본값 설정
        $data['tenant_id'] = $this->tenantId();
        $data['created_by'] = $this->apiUserId();

        // 우선순위가 지정되지 않은 경우 마지막으로 설정
        if (!isset($data['priority'])) {
            $maxPriority = BomConditionRule::where('tenant_id', $this->tenantId())
                ->where('model_id', $data['model_id'])
                ->max('priority') ?? 0;
            $data['priority'] = $maxPriority + 1;
        }

        // 규칙명 중복 체크
        $this->validateRuleNameUnique($data['model_id'], $data['name']);

        // 조건식 검증
        $rule = new BomConditionRule($data);
        $conditionErrors = $rule->validateConditionExpression();

        if (!empty($conditionErrors)) {
            throw new \InvalidArgumentException(__('error.invalid_condition_expression') . ': ' . implode(', ', $conditionErrors));
        }

        // 대상 아이템 처리
        if (isset($data['target_items']) && is_string($data['target_items'])) {
            $data['target_items'] = json_decode($data['target_items'], true);
        }

        // 대상 아이템 검증
        $this->validateTargetItems($data['target_items'] ?? [], $data['action']);

        $rule = BomConditionRule::create($data);

        return $rule->fresh();
    }

    /**
     * 조건 규칙 수정
     */
    public function updateRule(int $id, array $data): BomConditionRule
    {
        $rule = $this->getRule($id);

        // 규칙명 변경 시 중복 체크
        if (isset($data['name']) && $data['name'] !== $rule->name) {
            $this->validateRuleNameUnique($rule->model_id, $data['name'], $id);
        }

        // 조건식 변경 시 검증
        if (isset($data['condition_expression'])) {
            $tempRule = new BomConditionRule(array_merge($rule->toArray(), $data));
            $conditionErrors = $tempRule->validateConditionExpression();

            if (!empty($conditionErrors)) {
                throw new \InvalidArgumentException(__('error.invalid_condition_expression') . ': ' . implode(', ', $conditionErrors));
            }
        }

        // 대상 아이템 처리
        if (isset($data['target_items']) && is_string($data['target_items'])) {
            $data['target_items'] = json_decode($data['target_items'], true);
        }

        // 대상 아이템 검증
        if (isset($data['target_items']) || isset($data['action'])) {
            $action = $data['action'] ?? $rule->action;
            $targetItems = $data['target_items'] ?? $rule->target_items;
            $this->validateTargetItems($targetItems, $action);
        }

        $data['updated_by'] = $this->apiUserId();
        $rule->update($data);

        return $rule->fresh();
    }

    /**
     * 조건 규칙 삭제
     */
    public function deleteRule(int $id): bool
    {
        $rule = $this->getRule($id);

        $rule->update(['deleted_by' => $this->apiUserId()]);
        $rule->delete();

        return true;
    }

    /**
     * 조건 규칙 우선순위 변경
     */
    public function reorderRules(int $modelId, array $orderData): bool
    {
        $this->validateModelAccess($modelId);

        foreach ($orderData as $item) {
            BomConditionRule::where('tenant_id', $this->tenantId())
                ->where('model_id', $modelId)
                ->where('id', $item['id'])
                ->update([
                    'priority' => $item['priority'],
                    'updated_by' => $this->apiUserId()
                ]);
        }

        return true;
    }

    /**
     * 조건 규칙 복사 (다른 모델로)
     */
    public function copyRulesToModel(int $sourceModelId, int $targetModelId): Collection
    {
        $this->validateModelAccess($sourceModelId);
        $this->validateModelAccess($targetModelId);

        $sourceRules = $this->getRulesByModel($sourceModelId);
        $copiedRules = collect();

        foreach ($sourceRules as $sourceRule) {
            $data = $sourceRule->toArray();
            unset($data['id'], $data['created_at'], $data['updated_at'], $data['deleted_at']);

            $data['model_id'] = $targetModelId;
            $data['created_by'] = $this->apiUserId();

            // 이름 중복 시 수정
            $originalName = $data['name'];
            $counter = 1;
            while ($this->isRuleNameExists($targetModelId, $data['name'])) {
                $data['name'] = $originalName . '_' . $counter;
                $counter++;
            }

            $copiedRule = BomConditionRule::create($data);
            $copiedRules->push($copiedRule);
        }

        return $copiedRules;
    }

    /**
     * 조건 평가 및 적용할 규칙 찾기
     */
    public function getApplicableRules(int $modelId, array $variables): Collection
    {
        $this->validateModelAccess($modelId);

        $rules = $this->getRulesByModel($modelId);
        $applicableRules = collect();

        foreach ($rules as $rule) {
            if ($rule->evaluateCondition($variables)) {
                $applicableRules->push($rule);
            }
        }

        return $applicableRules;
    }

    /**
     * 조건 규칙을 BOM 아이템에 적용
     */
    public function applyRulesToBomItems(int $modelId, array $bomItems, array $variables): array
    {
        $applicableRules = $this->getApplicableRules($modelId, $variables);

        // 우선순위 순서대로 규칙 적용
        foreach ($applicableRules as $rule) {
            $bomItems = $rule->applyAction($bomItems);
        }

        return $bomItems;
    }

    /**
     * 조건식 검증 (문법 체크)
     */
    public function validateConditionExpression(int $modelId, string $expression): array
    {
        $this->validateModelAccess($modelId);

        $tempRule = new BomConditionRule([
            'condition_expression' => $expression,
            'model_id' => $modelId
        ]);

        return $tempRule->validateConditionExpression();
    }

    /**
     * 조건식 테스트 (실제 변수값으로 평가)
     */
    public function testConditionExpression(int $modelId, string $expression, array $variables): array
    {
        $this->validateModelAccess($modelId);

        $result = [
            'valid' => false,
            'result' => null,
            'error' => null
        ];

        try {
            $tempRule = new BomConditionRule([
                'condition_expression' => $expression,
                'model_id' => $modelId
            ]);

            $validationErrors = $tempRule->validateConditionExpression();
            if (!empty($validationErrors)) {
                $result['error'] = implode(', ', $validationErrors);
                return $result;
            }

            $evaluationResult = $tempRule->evaluateCondition($variables);
            $result['valid'] = true;
            $result['result'] = $evaluationResult;
        } catch (\Throwable $e) {
            $result['error'] = $e->getMessage();
        }

        return $result;
    }

    /**
     * 모델의 사용 가능한 변수 목록 조회 (매개변수 + 공식)
     */
    public function getAvailableVariables(int $modelId): array
    {
        $this->validateModelAccess($modelId);

        $parameterService = new ModelParameterService();
        $formulaService = new ModelFormulaService();

        $parameters = $parameterService->getParametersByModel($modelId);
        $formulas = $formulaService->getFormulasByModel($modelId);

        $variables = [];

        foreach ($parameters as $parameter) {
            $variables[] = [
                'name' => $parameter->name,
                'label' => $parameter->label,
                'type' => $parameter->type,
                'source' => 'parameter'
            ];
        }

        foreach ($formulas as $formula) {
            $variables[] = [
                'name' => $formula->name,
                'label' => $formula->label,
                'type' => 'NUMBER', // 공식 결과는 숫자
                'source' => 'formula'
            ];
        }

        return $variables;
    }

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

    /**
     * 규칙명 중복 검증
     */
    private function validateRuleNameUnique(int $modelId, string $name, ?int $excludeId = null): void
    {
        $query = BomConditionRule::where('tenant_id', $this->tenantId())
            ->where('model_id', $modelId)
            ->where('name', $name);

        if ($excludeId) {
            $query->where('id', '!=', $excludeId);
        }

        if ($query->exists()) {
            throw new \InvalidArgumentException(__('error.rule_name_duplicate'));
        }
    }

    /**
     * 규칙명 존재 여부 확인
     */
    private function isRuleNameExists(int $modelId, string $name): bool
    {
        return BomConditionRule::where('tenant_id', $this->tenantId())
            ->where('model_id', $modelId)
            ->where('name', $name)
            ->exists();
    }

    /**
     * 대상 아이템 검증
     */
    private function validateTargetItems(array $targetItems, string $action): void
    {
        if (empty($targetItems)) {
            throw new \InvalidArgumentException(__('error.target_items_required'));
        }

        foreach ($targetItems as $index => $item) {
            if (!isset($item['product_id']) && !isset($item['material_id'])) {
                throw new \InvalidArgumentException(__('error.target_item_missing_reference', ['index' => $index]));
            }

            // REPLACE 액션의 경우 replace_from 필요
            if ($action === BomConditionRule::ACTION_REPLACE && !isset($item['replace_from'])) {
                throw new \InvalidArgumentException(__('error.replace_from_required', ['index' => $index]));
            }

            // 수량 검증
            if (isset($item['quantity']) && (!is_numeric($item['quantity']) || $item['quantity'] <= 0)) {
                throw new \InvalidArgumentException(__('error.invalid_quantity', ['index' => $index]));
            }

            // 낭비율 검증
            if (isset($item['waste_rate']) && (!is_numeric($item['waste_rate']) || $item['waste_rate'] < 0 || $item['waste_rate'] > 100)) {
                throw new \InvalidArgumentException(__('error.invalid_waste_rate', ['index' => $index]));
            }
        }
    }

    /**
     * 규칙 활성화/비활성화
     */
    public function toggleRuleStatus(int $id): BomConditionRule
    {
        $rule = $this->getRule($id);

        $rule->update([
            'is_active' => !$rule->is_active,
            'updated_by' => $this->apiUserId()
        ]);

        return $rule->fresh();
    }

    /**
     * 규칙 실행 로그 (디버깅용)
     */
    public function getRuleExecutionLog(int $modelId, array $variables): array
    {
        $this->validateModelAccess($modelId);

        $rules = $this->getRulesByModel($modelId);
        $log = [];

        foreach ($rules as $rule) {
            $logEntry = [
                'rule_id' => $rule->id,
                'rule_name' => $rule->name,
                'condition' => $rule->condition_expression,
                'priority' => $rule->priority,
                'evaluated' => false,
                'result' => false,
                'action' => $rule->action,
                'error' => null
            ];

            try {
                $logEntry['evaluated'] = true;
                $logEntry['result'] = $rule->evaluateCondition($variables);
            } catch (\Throwable $e) {
                $logEntry['error'] = $e->getMessage();
            }

            $log[] = $logEntry;
        }

        return $log;
    }
}