/**
 * 客观题试卷服务模块
 * 负责试卷数据获取和处理
 */

import { questionApi } from '../../../config/question_api.js';

/**
 * 获取试卷详情
 * @param {String} paperId - 试卷ID
 * @param {String} taskId - 任务ID
 * @returns {Promise} 处理后的试卷数据
 */
export function fetchQuestionPaper(paperId, taskId) {
	return new Promise((resolve, reject) => {
		if (!paperId) {
			reject(new Error('试卷ID不能为空'));
			return;
		}

		questionApi.getPaperDetail(paperId)
			.then(res => {
				let paperInfo = null;
				if (res && res.code === 200 && res.data) {
					paperInfo = res.data;
				} else if (res && res.success === true && (res.paper || res.data)) {
					paperInfo = res.paper || res.data;
				}

				if (paperInfo) {
					if (!paperInfo.questions || !Array.isArray(paperInfo.questions)) {
						reject(new Error('试卷数据格式错误'));
						return;
					}

					const mapped = paperInfo.questions.map(q => {
						// Fiber 后端返回的格式：QuestionInfo
						// { id, type (QuestionType: 1=主观题, 2=选择题, 3=判断题, 4=填空题), title, content, answer, explanation, options ([]string), tags }
						
						// 兼容旧格式（PHP后端）
						if (q && (q.question_id || q.question_content || q.question_type)) {
							return {
								...q,
								id: q.question_id,
								title: q.question_content,
								type: q.question_type,
								materials: q.materials || [],
								options: (q.options || []).map(opt => ({
									...opt,
									id: opt.option_id,
									content: opt.option_content,
									label: opt.option_label
								})),
								user_answer: q.user_answer || null,
								explanation: q.explanation || ''
							};
						} else {
							// Fiber 后端格式
							// type: 1=主观题, 2=选择题(单选), 3=判断题, 4=填空题
							// 对于客观题，type 应该是 2 (选择题)
							const opts = Array.isArray(q.options) ? q.options.map((text, idx) => ({
								id: idx + 1,
								content: text,
								label: String.fromCharCode(65 + idx) // A, B, C...
							})) : [];
							
							// 映射题目类型
							// Fiber: 2=选择题 -> 前端: 'single_choice' 或 'multiple_choice'
							// 这里默认是单选，如果需要判断多选，可能需要根据其他字段或答案格式
							let mappedType = 'single_choice';
							if (q.type === 2) {
								// 选择题，根据答案是否包含逗号判断单选或多选
								const answer = q.answer || '';
								mappedType = answer.includes(',') ? 'multiple_choice' : 'single_choice';
							} else if (q.type === 3) {
								mappedType = 'true_false';
							} else if (q.type === 4) {
								mappedType = 'fill_blank';
							}
							
							return {
								...q,
								id: q.id,
								title: q.title || q.content || '',
								type: mappedType,
								material_id: q.material_id || null, // 保留题目关联的材料ID
								materials: q.materials || [], // Fiber 后端可能没有 materials 字段
								options: opts,
								user_answer: q.user_answer || null,
								explanation: q.explanation || ''
							};
						}
					});
					
					const questions = mapped.filter(q => Array.isArray(q.options) && q.options.length > 0);

					const answers = questions.map(question => {
						const optionsLength = question.options.length;
						const arr = new Array(optionsLength).fill(false);
						if (question.user_answer) {
							const userAnsArr = question.user_answer.split(',').map(s => s.trim()).filter(Boolean);
							userAnsArr.forEach(ans => {
								const idx = question.options.findIndex(opt => opt.label === ans);
								if (idx !== -1) arr[idx] = true;
							});
						}
						return arr;
					});

					// 确保 paperInfo 包含必要的字段
					const finalPaperInfo = {
						...paperInfo,
						title: paperInfo.title || '',
						description: paperInfo.description || '',
						duration_minutes: paperInfo.duration_minutes || 0 // Fiber 后端可能没有此字段，默认为 0
					};

					// 材料列表：后端 /paper/detail 返回 paper.materials，用于背景层左右滑动展示
					const materials = Array.isArray(paperInfo.materials) ? paperInfo.materials : [];

					resolve({
						paperInfo: finalPaperInfo,
						questions,
						answers,
						questionAnsweredStatus: answers.map(arr => arr.some(v => v)),
						materials
					});
				} else {
					reject(new Error((res && res.message) || (res && res.msg) || '获取试卷失败'));
				}
			})
			.catch(err => {
				console.error('API调用失败:', err);
				reject(err);
			});
	});
}