var config = require('./../config.js')
const mysql = require("mysql")
const async = require("async");

const pool = mysql.createPool({
    ...config.db
})


// var pool = mysql.createPool({
//     host: "144.48.4.186",
//     user: "noderest",
//     password: "8WBtsejYGiEESJMh",
//     database: "noderest",
//     connectionLimit: 33,
//     port: "3306",
//     waitForConnections: false
// });
//mysql事务处理
let  execTrans =function(sqlparamsEntities, callback) {
    //建立连接
    pool.getConnection(function (err, connection) {
        if (err) {
            //抛出连接错误
            return callback(err, null);
        }
        connection.beginTransaction(function (err) {
            if (err) {
                return callback(err, null);
            }
            console.log("开始执行transaction，共执行" + sqlparamsEntities.length + "条数据");
            var funcAry = [];
            sqlparamsEntities.forEach(function (sql_param) {
                var temp = function (cb) {
                    // var sql = sql_param.sql;
                    // var param = sql_param.params;
                    connection.query(sql_param, function (tErr, rows, fields) {
                        if (tErr) {
                            connection.rollback(function () {
                                console.log("事务失败，" + sql_param + "，ERROR：" + tErr);
                                throw tErr;
                            });
                        } else {
                            return cb(null, 'ok');
                        }
                    })
                };
                funcAry.push(temp);
            });

            async.series(funcAry, function (err, result) {
                console.log("transaction error: " + err);
                if (err) {
                    connection.rollback(function (err) {
                        console.log("transaction error: " + err);
                        connection.release();
                        return callback(err, null);
                    });
                } else {
                    connection.commit(function (err, info) {
                        console.log("transaction info: " + JSON.stringify(info));
                        if (err) {
                            console.log("执行事务失败，" + err);
                            connection.rollback(function (err) {
                                console.log("transaction error: " + err);
                                connection.release();
                                return callback(err, null);
                            });
                        } else {
                            connection.release();
                            return callback(null, info);
                        }
                    })
                }
            })
        });
    });
}

let query = function (sql, values) {
    return new Promise((resolve, reject) => {
        pool.getConnection(function (err, connection) {
            if (err) {
                resolve(err)
            } else {
                connection.query(sql, values, (err, rows) => {

                    if (err) {
                        reject(err)
                    } else {
                        resolve(rows)
                    }
                    connection.release()
                })
            }
        })
    })

}

let createTable = function (sql) {
    return query(sql, [])
}

let findDataLast = function (table) {
    let _sql = "SELECT * FROM ?? ORDER BY id DESC LIMIT 1;"
    return query(_sql, [table])
}

let findDataById = function (table, id) {
    let _sql = "SELECT * FROM ?? WHERE id = ? "
    return query(_sql, [table, id, start, end])
}


let findDataByPage = function (table, keys, start, end) {
    let _sql = "SELECT ?? FROM ??  LIMIT ? , ?"
    return query(_sql, [keys, table, start, end])
}


let insertData = function (table, values) {
    let _sql = "INSERT INTO ?? SET ?"
    return query(_sql, [table, values])
}


let updateData = function (table, values, id) {
    let _sql = "UPDATE ?? SET ? WHERE id = ?"
    return query(_sql, [table, values, id])
}


let deleteDataById = function (table, id) {
    let _sql = "DELETE FROM ?? WHERE id = ?"
    return query(_sql, [table, id])
}


let select = function (table, keys) {
    let _sql = "SELECT ?? FROM ?? "
    return query(_sql, [keys, table])
}

let count = function (table) {
    let _sql = "SELECT COUNT(*) AS total_count FROM ?? "
    return query(_sql, [table])
}

module.exports = {
    query,
    findDataLast,
    createTable,
    findDataById,
    findDataByPage,
    deleteDataById,
    insertData,
    updateData,
    select,
    count,
    execTrans,
}