const db = uniCloud.database();
const _ = db.command;
const uniID = require('uni-id-common');

const ARTICLE_DB = 'uni-cms-articles';

module.exports = {
	_before: function () { // 通用预处理器
		this.uniID = uniID.createInstance({
			context: this.getClientInfo()
		});
	},

	/** 校验登录并返回 payload */
	async _requireLogin() {
		const payload = await this.uniID.checkToken(this.getUniIdToken());
		if (payload.errCode) throw new Error('登录状态失效，请重新登录');
		return payload;
	},

	/**
	 * 读取文章详情
	 * 只返回已发布文章；作者与管理员可读自己的草稿
	 */
	async getDetail(query) {
		try {
			const id = query && query.id;
			if (!id) return { code: 400, msg: '缺少文章 id' };

			const res = await db.collection(ARTICLE_DB).doc(id).get();
			const article = res.data && res.data[0];
			if (!article) return { code: 404, msg: '文章不存在' };

			if (article.article_status !== 1) {
				const payload = await this.uniID.checkToken(this.getUniIdToken());
				const owner = !payload.errCode && article.user_id === payload.uid;
				const admin = !payload.errCode && (payload.role || []).includes('admin');
				if (!owner && !admin) {
					return { code: 403, msg: '无权查看该文章' };
				}
			}
			return { code: 200, data: article };
		} catch (e) {
			return { code: 500, msg: e.message };
		}
	},

	/**
	 * 是否已投过票：以登录态为准，不再采信客户端传入的 user_id
	 */
	async isSelectVote(query) {
		try {
			const payload = await this._requireLogin();
			const vote_id = query && query.vote_id;
			if (!vote_id) return { code: 400, msg: '缺少 vote_id' };

			const res = await db.collection("cms-vote")
				.where({
					user_id: payload.uid,
					vote_id: vote_id
				})
				.count();

			return {
				code: 200,
				isSelectVote: res.total > 0
			};
		} catch (e) {
			return { code: 500, msg: e.message };
		}
	},

	/**
	 * 当前登录用户对某文章的点赞/收藏状态
	 */
	async getInfo(query) {
		try {
			const payload = await this._requireLogin();
			const article_id = query && query.article_id;
			if (!article_id) return { code: 400, msg: '缺少 article_id' };

			const [likeRes, collectRes] = await Promise.all([
				db.collection("cms-articles-like").where({
					user_id: payload.uid,
					article_id
				}).count(),
				db.collection("cms-articles-collect").where({
					user_id: payload.uid,
					article_id
				}).count()
			]);

			return {
				code: 200,
				isLike: likeRes.total > 0,
				isCollect: collectRes.total > 0
			};
		} catch (e) {
			console.log(e.message);
			return { code: 500, msg: e.message };
		}
	},

	/**
	 * 按 id 读取公开文章字段。
	 * 原实现用了未定义变量 dbCollectionName 且硬编码文档 id，调用必然抛错。
	 */
	async get(query) {
		try {
			const id = query && (query.id || query._id);
			if (!id) return { code: 400, msg: '缺少文章 id' };

			const res = await db.collection(ARTICLE_DB).doc(id).field(
				"_id,user_id,category_id,title,content,excerpt,article_status,thumbnail,publish_date"
			).get();

			const article = res.data && res.data[0];
			if (!article) return { code: 404, msg: '文章不存在' };
			if (article.article_status !== 1) {
				const payload = await this.uniID.checkToken(this.getUniIdToken());
				const owner = !payload.errCode && article.user_id === payload.uid;
				const admin = !payload.errCode && (payload.role || []).includes('admin');
				if (!owner && !admin) return { code: 403, msg: '无权查看该文章' };
			}
			return { code: 200, data: article };
		} catch (e) {
			return { code: 500, msg: e.message };
		}
	},

	/**
	 * 某篇文章的阅读记录（详情页用于展示"谁看过"）
	 * 只有文章作者（或管理员）能看，普通读者不返回任何数据。
	 */
	async getCmsArticleLog(query) {
		try {
			const payload = await this._requireLogin();
			const article_id = query && query.article_id;
			if (!article_id) return { code: 400, msg: '缺少 article_id' };

			const articleRes = await db.collection(ARTICLE_DB).doc(article_id).field({ user_id: true }).get();
			const article = articleRes.data && articleRes.data[0];
			if (!article) return { code: 404, msg: '文章不存在' };

			const isAdmin = (payload.role || []).includes('admin');
			if (article.user_id !== payload.uid && !isAdmin) {
				return { code: 403, msg: '只有作者可以查看阅读记录' };
			}

			const page = Math.max(1, Number(query.page) || 1);
			const pageSize = Math.min(50, Math.max(1, Number(query.page_size) || 21));

			// 浏览日志的读权限是"仅本人"，这里用云函数的管理连接跨用户查询
			const logsRes = await db.collection('cms-articles-log')
				.where({ article_id })
				.orderBy('last_view_time', 'desc')
				.skip((page - 1) * pageSize)
				.limit(pageSize)
				.field('article_id, user_id, first_view_time, last_view_time')
				.get();

			const uids = [...new Set(logsRes.data.map((l) => l.user_id).filter(Boolean))];
			const usersRes = uids.length
				? await db.collection('uni-id-users').where({ _id: _.in(uids) }).field('_id,avatar_file').get()
				: { data: [] };
			const userMap = new Map(usersRes.data.map((u) => [u._id, u]));

			return {
				code: 200,
				cmsArticleLog: logsRes.data.map((log) => ({
					...log,
					user_id: [userMap.get(log.user_id) || { _id: log.user_id, avatar_file: {} }]
				}))
			};
		} catch (e) {
			console.log(e.message);
			return { code: 500, msg: e.message };
		}
	}
}