<?php

namespace App\Http\Requests;

use Illuminate\Foundation\Http\FormRequest;
use Shared\Models\Products\ModelFormula;

class ModelFormulaRequest extends FormRequest
{
    /**
     * Determine if the user is authorized to make this request.
     */
    public function authorize(): bool
    {
        return true;
    }

    /**
     * Get the validation rules that apply to the request.
     */
    public function rules(): array
    {
        return [
            'model_id' => 'required|integer|exists:models,id',
            'name' => 'required|string|max:50|regex:/^[a-zA-Z][a-zA-Z0-9_]*$/',
            'label' => 'required|string|max:100',
            'expression' => 'required|string|max:1000',
            'unit' => 'nullable|string|max:20',
            'order' => 'nullable|integer|min:1',
            'description' => 'nullable|string|max:500',
            'is_active' => 'boolean',
        ];
    }

    /**
     * Get custom messages for validator errors.
     */
    public function messages(): array
    {
        return [
            'name.regex' => __('error.formula_name_format'),
            'expression.required' => __('error.formula_expression_required'),
        ];
    }

    /**
     * Configure the validator instance.
     */
    public function withValidator($validator): void
    {
        $validator->after(function ($validator) {
            $this->validateFormulaNameUnique($validator);
            $this->validateFormulaExpression($validator);
            $this->validateDependencies($validator);
        });
    }

    /**
     * 공식명 중복 검증
     */
    private function validateFormulaNameUnique($validator): void
    {
        if (!$this->input('model_id') || !$this->input('name')) {
            return;
        }

        $query = ModelFormula::where('model_id', $this->input('model_id'))
            ->where('name', $this->input('name'));

        // 수정 시 자기 자신 제외
        if ($this->route('id')) {
            $query->where('id', '!=', $this->route('id'));
        }

        if ($query->exists()) {
            $validator->errors()->add('name', __('error.formula_name_duplicate'));
        }

        // 매개변수명과 중복 검증
        $parameterExists = \Shared\Models\Products\ModelParameter::where('model_id', $this->input('model_id'))
            ->where('name', $this->input('name'))
            ->exists();

        if ($parameterExists) {
            $validator->errors()->add('name', __('error.formula_name_conflicts_with_parameter'));
        }
    }

    /**
     * 공식 표현식 검증
     */
    private function validateFormulaExpression($validator): void
    {
        if (!$this->input('expression')) {
            return;
        }

        $tempFormula = new ModelFormula([
            'expression' => $this->input('expression'),
            'model_id' => $this->input('model_id'),
        ]);

        $expressionErrors = $tempFormula->validateExpression();

        if (!empty($expressionErrors)) {
            foreach ($expressionErrors as $error) {
                $validator->errors()->add('expression', $error);
            }
        }
    }

    /**
     * 의존성 검증
     */
    private function validateDependencies($validator): void
    {
        if (!$this->input('model_id') || !$this->input('expression')) {
            return;
        }

        $tempFormula = new ModelFormula([
            'expression' => $this->input('expression'),
            'model_id' => $this->input('model_id'),
        ]);

        $dependencies = $tempFormula->extractVariables();

        if (empty($dependencies)) {
            return;
        }

        // 매개변수 목록 가져오기
        $parameters = \Shared\Models\Products\ModelParameter::where('model_id', $this->input('model_id'))
            ->active()
            ->pluck('name')
            ->toArray();

        // 기존 공식 목록 가져오기 (자기 자신 제외)
        $formulasQuery = ModelFormula::where('model_id', $this->input('model_id'))
            ->active();

        if ($this->route('id')) {
            $formulasQuery->where('id', '!=', $this->route('id'));
        }

        $formulas = $formulasQuery->pluck('name')->toArray();

        $validNames = array_merge($parameters, $formulas);

        foreach ($dependencies as $dep) {
            if (!in_array($dep, $validNames)) {
                $validator->errors()->add('expression', __('error.dependency_not_found', ['name' => $dep]));
            }
        }

        // 순환 의존성 검증
        $this->validateCircularDependency($validator, $dependencies);
    }

    /**
     * 순환 의존성 검증
     */
    private function validateCircularDependency($validator, array $dependencies): void
    {
        if (!$this->input('model_id') || !$this->input('name')) {
            return;
        }

        $allFormulasQuery = ModelFormula::where('model_id', $this->input('model_id'))
            ->active();

        if ($this->route('id')) {
            $allFormulasQuery->where('id', '!=', $this->route('id'));
        }

        $allFormulas = $allFormulasQuery->get();

        // 현재 공식을 임시로 추가
        $tempFormula = new ModelFormula([
            'name' => $this->input('name'),
            'dependencies' => $dependencies,
        ]);
        $allFormulas->push($tempFormula);

        if ($this->hasCircularDependency($tempFormula, $allFormulas->toArray())) {
            $validator->errors()->add('expression', __('error.circular_dependency_detected'));
        }
    }

    /**
     * 순환 의존성 검사
     */
    private function hasCircularDependency(ModelFormula $formula, array $allFormulas, array $visited = []): bool
    {
        if (in_array($formula->name, $visited)) {
            return true;
        }

        $visited[] = $formula->name;

        foreach ($formula->dependencies ?? [] as $dep) {
            foreach ($allFormulas as $depFormula) {
                if ($depFormula->name === $dep) {
                    if ($this->hasCircularDependency($depFormula, $allFormulas, $visited)) {
                        return true;
                    }
                    break;
                }
            }
        }

        return false;
    }
}