const cloud = require('wx-server-sdk');

cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV });

const VALID_STATUS = new Set(['draft', 'active', 'hidden']);
const VALID_DIFFICULTY = new Set([1, 2, 3, 4]);

function toInt(value, fallback = 0) {
    const number = Number(value);
    if (!Number.isFinite(number)) return fallback;
    return Math.round(number);
}

function toStringArray(value) {
    if (!Array.isArray(value)) return [];
    return value.map((item) => String(item || '').trim()).filter(Boolean);
}

async function ensureCategoryExists(db, category) {
    try {
        await db.collection('categories').doc(category).get();
        return true;
    } catch (error) {
        return false;
    }
}

async function validatePayload(event, db) {
    const id = String(event.id || '').trim();
    const title = String(event.title || '').trim();
    const subtitle = String(event.subtitle || '').trim();
    const category = String(event.category || '').trim();
    const subcategory = String(event.subcategory || '').trim();
    const path = String(event.path || '').trim();
    const previewImg = String(event.previewImg || '').trim();
    const ageMin = toInt(event.ageMin, 0);
    const ageMax = toInt(event.ageMax, 0);
    const grade = toInt(event.grade, 0);
    const difficulty = toInt(event.difficulty, 0);
    const tags = toStringArray(event.tags);
    const isNew = !!event.isNew;
    const isHot = !!event.isHot;
    const sortOrder = toInt(event.sortOrder, 0);
    const downloads = toInt(event.downloads, 0);
    const likes = toInt(event.likes, 0);
    const status = String(event.status || 'draft').trim();

    if (!id) throw new Error('题型 id 不能为空');
    if (!title) throw new Error('标题不能为空');
    if (!subtitle) throw new Error('副标题不能为空');
    if (!category) throw new Error('分类不能为空');
    if (!path) throw new Error('页面路径不能为空');
    if (!previewImg) throw new Error('预览图不能为空');
    if (ageMin < 0 || ageMax < ageMin) throw new Error('年龄范围不合法');
    if (!VALID_DIFFICULTY.has(difficulty)) throw new Error('难度不合法');
    if (!VALID_STATUS.has(status)) throw new Error('状态不合法');
    if (!(await ensureCategoryExists(db, category))) {
        throw new Error('分类不合法，categories 集合中不存在该分类');
    }

    return {
        id,
        title,
        subtitle,
        category,
        subcategory,
        path,
        previewImg,
        ageMin,
        ageMax,
        grade,
        difficulty,
        tags,
        isNew,
        isHot,
        sortOrder,
        downloads,
        likes,
        status,
    };
}

exports.main = async (event) => {
    try {
        const db = cloud.database();
        const payload = await validatePayload(event, db);
        const collection = db.collection('worksheets');

        const record = {
            title: payload.title,
            subtitle: payload.subtitle,
            category: payload.category,
            subcategory: payload.subcategory,
            path: payload.path,
            ageMin: payload.ageMin,
            ageMax: payload.ageMax,
            grade: payload.grade,
            difficulty: payload.difficulty,
            previewImg: payload.previewImg,
            tags: payload.tags,
            isNew: payload.isNew,
            isHot: payload.isHot,
            sortOrder: payload.sortOrder,
            downloads: payload.downloads,
            likes: payload.likes,
            status: payload.status,
            updatedAt: db.serverDate(),
        };

        try {
            const { data } = await collection.doc(payload.id).get();

            await collection.doc(payload.id).update({
                data: record,
            });

            return {
                success: true,
                data: {
                    _id: payload.id,
                    createdAt: data.createdAt,
                    ...record,
                },
            };
        } catch (error) {
            await collection.doc(payload.id).set({
                data: {
                    ...record,
                    createdAt: db.serverDate(),
                },
            });

            return {
                success: true,
                data: {
                    _id: payload.id,
                    ...record,
                },
            };
        }
    } catch (error) {
        return {
            success: false,
            message: error instanceof Error ? error.message : '发布题型失败',
        };
    }
};