/**
 * 答题状态（顺序练习 / 答题卡共用）
 * 用 reassign 方式更新数组，保证 uvue 下响应式可靠触发。
 */
import { reactive } from 'vue'
import { quizQuestions } from '@/mock/index.uts'

export type HrQuizState = {
	/** 每题已选选项下标，-1 表示未作答 */
	answers : number[]
	/** 是否标记 */
	marked : boolean[]
	/** 当前题号（从 0 开始） */
	current : number
	/** 是否已交卷 */
	submitted : boolean
}

function emptyAnswers() : number[] {
	const arr : number[] = []
	for (let i = 0; i < quizQuestions.length; i++) { arr.push(-1) }
	return arr
}

function emptyMarks() : boolean[] {
	const arr : boolean[] = []
	for (let i = 0; i < quizQuestions.length; i++) { arr.push(false) }
	return arr
}

export const quizState = reactive({
	answers: emptyAnswers(),
	marked: emptyMarks(),
	current: 0,
	submitted: false
} as HrQuizState)

/** 设置某题答案 */
export function setAnswer(index : number, option : number) : void {
	const arr : number[] = []
	for (let i = 0; i < quizState.answers.length; i++) {
		arr.push(i == index ? option : quizState.answers[i])
	}
	quizState.answers = arr
}

/** 切换标记 */
export function toggleMark(index : number) : void {
	const arr : boolean[] = []
	for (let i = 0; i < quizState.marked.length; i++) {
		arr.push(i == index ? !quizState.marked[i] : quizState.marked[i])
	}
	quizState.marked = arr
}

/** 已答数量 */
export function answeredCount() : number {
	let n = 0
	for (let i = 0; i < quizState.answers.length; i++) {
		if (quizState.answers[i] >= 0) { n++ }
	}
	return n
}

/** 标记数量 */
export function markedCount() : number {
	let n = 0
	for (let i = 0; i < quizState.marked.length; i++) {
		if (quizState.marked[i]) { n++ }
	}
	return n
}

/** 重置 */
export function resetQuiz() : void {
	quizState.answers = emptyAnswers()
	quizState.marked = emptyMarks()
	quizState.current = 0
	quizState.submitted = false
}