<?php

namespace App\Models;

class StudyAsk extends SoftDeletesModel
{
    protected $table = 'study_asks';

    protected $casts = [
        'answer' => 'array',
        'type' => 'boolean',
    ];

    // 题目类型常量
    const TYPE_SINGLE = 1;    // 单选
    const TYPE_MULTIPLE = 2;  // 多选

    /**
     * 关联学习内容
     */
    public function study()
    {
        return $this->belongsTo(Study::class, 'study_id');
    }

    /**
     * 获取题目类型文本
     */
    public function getTypeTextAttribute()
    {
        $types = [
            self::TYPE_SINGLE => '单选题',
            self::TYPE_MULTIPLE => '多选题',
        ];
        return $types[$this->type] ?? '未知';
    }

    /**
     * 获取正确答案
     */
    public function getCorrectAnswers()
    {
        if (!$this->answer) {
            return [];
        }

        $correctAnswers = [];
        foreach ($this->answer as $option) {
            if (isset($option['result']) && $option['result'] == 1) {
                $correctAnswers[] = $option['content'] ?? '';
            }
        }
        return $correctAnswers;
    }

    /**
     * 获取所有选项
     */
    public function getOptions()
    {
        if (!$this->answer) {
            return [];
        }

        $options = [];
        foreach ($this->answer as $index => $option) {
            $options[] = [
                'index' => $index,
                'content' => $option['content'] ?? '',
                'is_correct' => isset($option['result']) && $option['result'] == 1,
            ];
        }
        return $options;
    }

    /**
     * 检查答案是否正确
     */
    public function checkAnswer($userAnswers)
    {
        $correctAnswers = $this->getCorrectAnswers();

        if ($this->type == self::TYPE_SINGLE) {
            // 单选题：用户答案必须是单个且与正确答案匹配
            if (is_array($userAnswers)) {
                $userAnswers = $userAnswers[0] ?? '';
            }
            return in_array($userAnswers, $correctAnswers);
        } else {
            // 多选题：用户答案必须与正确答案完全匹配
            if (!is_array($userAnswers)) {
                return false;
            }

            sort($userAnswers);
            sort($correctAnswers);
            return $userAnswers === $correctAnswers;
        }
    }

    /**
     * 获取题目难度（基于选项数量）
     */
    public function getDifficulty()
    {
        $optionCount = count($this->answer ?? []);

        if ($optionCount <= 2) {
            return '简单';
        } elseif ($optionCount <= 4) {
            return '中等';
        } else {
            return '困难';
        }
    }

    /**
     * 验证题目数据完整性
     */
    public function isValid()
    {
        // 检查基本信息
        if (empty($this->title) || empty($this->answer)) {
            return false;
        }

        // 检查答案格式
        if (!is_array($this->answer)) {
            return false;
        }

        // 检查是否有正确答案
        $hasCorrectAnswer = false;
        foreach ($this->answer as $option) {
            if (isset($option['result']) && $option['result'] == 1) {
                $hasCorrectAnswer = true;
                break;
            }
        }

        if (!$hasCorrectAnswer) {
            return false;
        }

        // 检查选项内容
        foreach ($this->answer as $option) {
            if (empty($option['content'])) {
                return false;
            }
        }

        return true;
    }

    /**
     * 获取题目统计信息
     */
    public function getStatistics()
    {
        return [
            'type' => $this->getTypeTextAttribute(),
            'difficulty' => $this->getDifficulty(),
            'option_count' => count($this->answer ?? []),
            'correct_answer_count' => count($this->getCorrectAnswers()),
            'is_valid' => $this->isValid(),
        ];
    }
}