csamsclient/app/src/main/java/com/gyf/csams/association/model/ExamViewModel.kt

package com.gyf.csams.association.model

import androidx.lifecycle.LiveData
import androidx.lifecycle.MutableLiveData
import com.gyf.csams.uikit.ScrollList
import com.gyf.csams.uikit.StringForm
import kotlin.random.Random

/**
 * 题型
 *
 */
enum class ExamType(val type:String){
    //选择题
    cq("选择题"),
    //开放题
    oq("开放题")
}

sealed class Exam{
    abstract val examType:ExamType
    abstract val question:StringForm
}


/**
 * 开放题
 *
 * @property examType 题型描述
 * @property question 问题
 */
data class OpenQuestionsVo(
    override val examType: ExamType = ExamType.oq, override val question: StringForm

) : Exam()

/**
 * 选择题
 *
 * @property examType 题型描述
 * @property answers 答案
 * @property rightAnswer 正确答案
 * @property question 问题
 */
data class ChoiceQuestionVo(override val examType: ExamType = ExamType.cq,
                            val answers:List<StringForm>,
                            val rightAnswer:Int,
                            override val question: StringForm
):Exam()




/**
 * 题库状态管理
 *
 */

/**
 * 问题长度
 */
const val QUESTION_TEXT_LENGTH=30

/**
 * 选择题选项数
 */
const val ANSWER_SIZE=4

/**
 * 答案长度
 *
 */
const val ANSWER_TEXT_LENGTH=15


class ExamViewModel:ScrollList<Exam>() {
    val questionIsNull: String = "问题不能为空"
    val deleteLeastOne: String="至少保留一道题目"
    val updateExam="更新题库"
    val back="返回"
    val menuName="入团题库"
    val deleteTip="确定删除此题目？"
    val addTip="确定添加此题目？"
    val actionLabel="确定"


    override val initSize = 10


    private val _newExam:MutableLiveData<Exam> = MutableLiveData(createExam(ExamType.cq))
    val newExam:LiveData<Exam> = _newExam

    init {
        load()
    }

    /**
     * 切换题型
     *
     */
    fun switchType(exam: Exam){
        if(exam is ChoiceQuestionVo) _newExam.value=createExam(ExamType.oq) else _newExam.value=createExam(ExamType.cq)
    }


    /**
     * 创建题目
     *
     * @param type
     * @return
     */
    private fun createExam(type: ExamType): Exam {
        val question=StringForm(formDesc = "问题",textLength = QUESTION_TEXT_LENGTH)
        return when(type){
            ExamType.cq-> ChoiceQuestionVo(
                answers = ('A'..'D').map { StringForm(formDesc = "选项",textLength = ANSWER_TEXT_LENGTH,value = "选项$it") },
                rightAnswer = 0,
                question = question
            )
            ExamType.oq-> OpenQuestionsVo(question = question)
        }
    }


    /**
     * 更新题目
     *
     */
    fun update(oldExam: Exam,newExam:Exam){
        if(oldExam==_newExam.value){
            _newExam.value=newExam
        }else{
            _data.value?.apply {
                this[indexOf(oldExam)]=newExam
                val list = mutableListOf<Exam>()
                list.addAll(this)
                _data.value?.clear()
                _data.value=list
            }
        }
    }

    /**
     * TODO 更新题库
     *
     * @param callback
     */
    fun updateExam(callback: (message: String) -> Unit){
        callback("功能尚未实现，敬请期待")

    }

    /**
     * 加载题目
     *
     */
    override fun load() {
        _data.value?.apply {
            repeat(initSize) {
                if (Random.nextBoolean()){
                    add(OpenQuestionsVo(question = StringForm(formDesc = "问题",textLength = QUESTION_TEXT_LENGTH,value = "这是一道开放题：$size")))
                } else{
                    add(
                        ChoiceQuestionVo(
                            question = StringForm(formDesc = "问题",textLength = QUESTION_TEXT_LENGTH,value = "这是一道选择题：$size"),
                            answers = ('A'..'D').map { StringForm(formDesc = "选项",textLength = ANSWER_TEXT_LENGTH,value = "选项$it") },
                            rightAnswer = Random.nextInt(ANSWER_SIZE)
                        )
                    )
                }

            }
        }
    }

    /**
     *TODO 加载更多题目
     *
     * @param callback
     */
    override fun loadMore(callback: (message: String) -> Unit) {
//        _data.value?.apply {
//            val list= mutableListOf<Exam>()
//            list.addAll(this)
//            list.apply {
//                repeat(10) {
//                    if (Random.nextBoolean()) add(OpenQuestionsVo(question = "这是一道开放题：$size")) else add(
//                        ChoiceQuestionVo(
//                            question = "这是一道选择题：$size，请从选项中选出正确答案",
//                            answers = listOf("选项A", "选项B", "选项C", "选项D"),
//                            rightAnswer = 3
//                        )
//                    )
//                }
//            }
//            _data.postValue(list)
//            callback("成功加载更多题目")
//        }

//        callback("功能尚未实现，敬请期待")
    }

    fun addQuestion() {
        _data.value?.apply {
            _newExam.value?.let{
                val list= mutableListOf<Exam>()
                list.addAll(this)
                list.add(it)
                _data.postValue(list)
            }
            _newExam.value=createExam(ExamType.cq)
        }
    }

    /**
     * TODO 删除题目
     *
     */
    fun deleteQuestion(exam: Exam) {
        _data.value?.apply {
            val list = mutableListOf<Exam>()
            remove(exam)
            list.addAll(this)
            _data.postValue(list)
        }
    }
}