// 定时更新 wait 表

const sleepUtils = require("../../utils/sleepUtils");
const { fill } = require("../../utils/stringUtils");

// 计算数组差集 （a - b）
function getDiffSet(a, b) {
    // let a = [1, 2, 3];
    // let b = [4, 5, 6, 1];
    // let c = a.filter(i => b.indexOf(i) == -1);
    // console.log(c);
    return a.filter(i => b.indexOf(i) == -1);
}

async function migrateIdsFromCheckToFetch(tableName, fieldName, insertSql = null) {
    // console.log(`更新待爬取列表: ${tableName}`);

    let stepLength = 5000;
    while (true) {
        // 从 check 表中分块查出待处理数据
        let idsResult = await dbUtils.query(`SELECT id FROM wait_check_${tableName} LIMIT ${stepLength}`, []);
        let ids = idsResult.map(row => row.id);
        // console.log("ids", ids);
        if (ids.length == 0) {
            // console.log(`${tableName} done.`);
            break;
        };

        // 查询出已处理的数据
        let skipIdsResult = await dbUtils.query(`SELECT ${fieldName} as id FROM ${tableName} WHERE ${fieldName} IN ?`, [[ids]]);
        let skipIds = skipIdsResult.map(row => row.id);
        // console.log("skipIds", skipIds);

        // 剩余要爬取的数据
        let finalIds = getDiffSet(ids, skipIds);
        // console.log("finalIds", finalIds);

        // 插入待爬取列表
        if (finalIds.length > 0) {
            var result = await dbUtils.query(insertSql ? insertSql : `INSERT IGNORE INTO wait_fetch_${tableName} (id) VALUES ?`, [finalIds.map(id => [id])]);
            // console.log(result);
        }


        // 从待检查表中删除
        if (ids.length > 0)
            await dbUtils.query(`DELETE FROM wait_check_${tableName} WHERE id IN ?`, [[ids]]);
        console.log(`table: ${tableName}\t| ${fill(ids[0], 10)} - ${fill(ids.slice(-1)[0], 10)} ${fill(`(${finalIds.length}/${ids.length})`, 10, ' ', true)}\t| affected: ${result?.affectedRows}`);
    }
}

async function getPromise(tableName, fieldName, insertSql) {
    try {
        return new Promise(async function (resolve) {
            await migrateIdsFromCheckToFetch(tableName, fieldName, insertSql);
            resolve();
        });
    } catch (e) {
        console.error(e);
        await sleepUtils.sleep(10 * 1000);
    }
}
async function updateWaitTable() {
    console.log(`更新待爬取列表`);
    await Promise.all([
        getPromise("song", "song_id"),
        getPromise("lyric", "song_id"),
        getPromise("comment", "song_id", `INSERT IGNORE INTO comment_progress (song_id) VALUES ?`),
        getPromise("album", "album_id"),
        getPromise("artist", "artist_id")
    ]);
    console.log("All done.\n");
}

module.exports = {
    updateWaitTable,
}