// ArrayBuffer转16进度字符串示例

function ab2hex(buffer) {

    const hexArr = Array.prototype.map.call(

        new Uint8Array(buffer),

        function(bit) {

            return ('00' + bit.toString(16)).slice(-2)

        }

    )

    return hexArr.join('')

}

// 16进制转字符串

async function hexCharCodeToStr(hex) {

    var arr = hex.split(""),

        out = "",

        len = hex.length / 2;

    for (var i = 0; i < len; i++) {

        out += String.fromCharCode(parseInt(hex.substr(i * 2, 2), 16));

    }

    // 此时的out为UTF-8

    //蓝牙使用的是UTF-8编码

    // 解决乱码问题 （JS默认是Unicode编码的 也就是UTF-16）

    return await utf8to16(out)

}

function utf8to16(str) {

    var out, i, len, c;

    var char2, char3;

    out = "";

    len = str.length;

    i = 0;

    while (i < len) {

        c = str.charCodeAt(i++);

        switch (c >> 4) {

            case 0:

            case 1:

            case 2:

            case 3:

            case 4:

            case 5:

            case 6:

            case 7:

                // 0xxxxxxx

                out += str.charAt(i - 1);

                break;

            case 12:

            case 13:

                // 110x xxxx 10xx xxxx

                char2 = str.charCodeAt(i++);

                out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));

                break;

            case 14:

                // 1110 xxxx 10xx xxxx 10xx xxxx

                char2 = str.charCodeAt(i++);

                char3 = str.charCodeAt(i++);

                out += String.fromCharCode(((c & 0x0F) << 12) |

                    ((char2 & 0x3F) << 6) |

                    ((char3 & 0x3F) << 0));

                break;

        }

    }

    return out;

}

function utf16to8(str) {

    var out, i, len, c;

    out = "";

    len = str.length;

    for(i = 0; i < len; i++) {

    c = str.charCodeAt(i);

    if ((c >= 0x0001) && (c <= 0x007F)) {

    out += str.charAt(i);

    } else if (c > 0x07FF) {

    out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F));

    out += String.fromCharCode(0x80 | ((c >> 6) & 0x3F));

    out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));

    } else {

    out += String.fromCharCode(0xC0 | ((c >> 6) & 0x1F));

    out += String.fromCharCode(0x80 | ((c >> 0) & 0x3F));

    }

    }

    return out;

}

// 字符串转16进制 str需要传入设备需要的utf-8（js字符串默认是Unicode编码utf16，需转成设备的utf8）解决中文问题,否则设备处理不了

function strToHexCharCode(str) {

if (str === "")

return "";

var hexCharCode = [];

// hexCharCode.push("0x");

for (var i = 0; i < str.length; i++) {

hexCharCode.push((str.charCodeAt(i)).toString(16));

}

return hexCharCode.join("");

}

//设置wifi

            setWifiInfo() {

                uni.showLoading({

                    title: 'wifi网络配置中..',

                    mask: false

                });

                //此时需要注意 wifi名为中文需要把中文的utf-16转成utf-8

                let body = {

                    "ssid":that.$lizhao.scale.utf16to8(that.picker.form.ssid),

                    "password": that.picker.form.password

                }

                let length = that.$lizhao.scale.switch_sl(JSON.stringify(body).length, 16) // 十进制转十六进制

                let stri = '0'

                for (let i = 0; i < (7 - length.length); i++) {

                    stri += '0'

                }

                let cmd = '0002' //2转成两位的16进制为00 02

                let len = stri + length //body的长度为39转成4位的16进制为00 00 00 26

                //十进制数据转换为16进制

                let body_16 = that.$lizhao.scale.strToHexCharCode(JSON.stringify(body))

                let hex = that.Bluetooth.agreement.magic + cmd + that.Bluetooth.agreement.id + len + body_16

                let arr = that.splitArr(hex)

                //多个指令串行发送，并行可能会失败

                that.writeCmd(arr, 0)

            },

            //arr为hex分割的数组，i为当前数组下标

            async writeCmd(arr, i) {

                let res = await that.$lizhao.bluetooth.writeBLECharacteristicValue(arr[i])

                if (res == 'writeBLECharacteristicValue:ok') {

                    i++

                    if (i > arr.length) {

                        return

                    }

                    that.writeCmd(arr, i)

                } else {

                    that.writeCmd(arr, i)

                }

            },

            //分割指令每20位分割一下，返回数组

            splitArr(hex) {

                let arr = []

                for (let a = 0; a < Math.ceil(hex.length / 20); a++) {

                    let str = hex.slice(a * 20, a * 20 + 20)

                    arr.push(str)

                }

                return arr

            }