const cloud = require('wx-server-sdk');
cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV });

const db = cloud.database();

exports.main = async (event, context) => {
    const wxContext = cloud.getWXContext();
    const openid = wxContext.OPENID;
    const unionid = wxContext.UNIONID || null;

    const { action } = event;

    switch (action) {
        case 'updateProfile':
            return await handleUpdateProfile(event, openid);
        default:
            return await handleSilentLogin(openid, unionid);
    }
};

function serializeUser(user) {
    return {
        ...user,
        createdAt:
            user.createdAt instanceof Date
                ? user.createdAt
                : user.createdAt?.toDate?.() || user.createdAt || null,
        lastActiveAt:
            user.lastActiveAt instanceof Date
                ? user.lastActiveAt
                : user.lastActiveAt?.toDate?.() || user.lastActiveAt || null,
    };
}

async function handleSilentLogin(openid, unionid) {
    const usersCollection = db.collection('users');

    const { data } = await usersCollection.where({ openid }).limit(1).get();

    const now = db.serverDate();

    if (data.length > 0) {
        const user = data[0];
        const updateData = { lastActiveAt: now };
        if (unionid && !user.unionid) {
            updateData.unionid = unionid;
        }
        await usersCollection.doc(user._id).update({ data: updateData });
        const latest = (
            await usersCollection.doc(user._id).get()
        ).data;

        return {
            code: 0,
            data: serializeUser(latest),
        };
    } else {
        const newUser = {
            openid,
            unionid,
            nickName: null,
            avatarUrl: null,
            totalDownloads: 0,
            createdAt: now,
            lastActiveAt: now,
        };
        const { _id } = await usersCollection.add({ data: newUser });
        const latest = (await usersCollection.doc(_id).get()).data;

        return {
            code: 0,
            data: serializeUser(latest),
        };
    }
}

async function handleUpdateProfile(event, openid) {
    const { nickName, avatarUrl } = event;
    const usersCollection = db.collection('users');

    const { data } = await usersCollection.where({ openid }).limit(1).get();

    if (data.length === 0) {
        return { code: -1, message: '用户不存在' };
    }

    const updateData = {};
    if (nickName !== undefined) updateData.nickName = nickName;
    if (avatarUrl !== undefined) updateData.avatarUrl = avatarUrl;
    updateData.lastActiveAt = db.serverDate();

    await usersCollection.doc(data[0]._id).update({ data: updateData });
    const latest = (await usersCollection.doc(data[0]._id).get()).data;

    return {
        code: 0,
        data: serializeUser(latest),
    };
}