package com.zy.common.utils;

import com.zy.common.model.annotations.*;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.Expression;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.lang.reflect.Array;
import java.lang.reflect.Field;
import java.nio.charset.StandardCharsets;
import java.util.*;

/**
 * Tcp协议报文基类
 * @author vincent
 */
public class Struct implements java.io.Serializable {

    private transient Map<String, byte[]> decodeByteMapping = new HashMap<>();
    private transient Map<String, byte[]> encodeByteMapping = new HashMap<>();
    // 解码前的原生字节数组
    private transient byte[] dataBytes = null;
    private transient byte[] decodeBytes = null;
    private transient byte[] encodeBytes = null;
    private transient byte[] unusedBytes = null;

    @SuppressWarnings({"unchecked", "rawtypes"})
    public static <T extends Struct> T decode(Class<? extends Struct> cls, byte[] bytes) throws Exception {
        Struct instance = cls.newInstance();
        return instance.decode(bytes);
    }

    // 字节数组 ===>> 转为十六进制字符串
    public static String toHex(byte[] bytes) {
        StringBuilder buf = new StringBuilder(bytes.length * 2);
        for (byte b : bytes) { // 使用String的format方法进行转换
            buf.append(String.format("%02x", b & 0xff));
        }
        return buf.toString().toUpperCase();
    }

    public static byte[] toBytes(String str) {
        if (str == null || str.trim().equals("")) return new byte[0];
        byte[] bytes = new byte[str.length() / 2];
        for (int i = 0; i < str.length() / 2; i++) {
            String subStr = str.substring(i * 2, i * 2 + 2);
            bytes[i] = (byte) Integer.parseInt(subStr, 16);
        }
        return bytes;
    }

    /**
     * @功能: BCD码转为10进制串(阿拉伯数据)
     * @参数: BCD码
     * @结果: 10进制串
     */
    public static String bcd2Str(byte[] bytes) {
        StringBuffer temp = new StringBuffer(bytes.length * 2);
        for (int i = 0; i < bytes.length; i++) {
            temp.append((byte) ((bytes[i] & 0xf0) >>> 4));
            temp.append((byte) (bytes[i] & 0x0f));
        }
        return temp.toString().substring(0, 1).equalsIgnoreCase("0") ? temp
                .toString().substring(1) : temp.toString();
    }

    /**
     * @功能: 10进制串转为BCD码
     * @参数: 10进制串
     * @结果: BCD码
     */
    public static byte[] str2Bcd(String asc) {
        int len = asc.length();
        int mod = len % 2;
        if (mod != 0) {
            asc = "0" + asc;
            len = asc.length();
        }
        byte abt[] = new byte[len];
        if (len >= 2) {
            len = len / 2;
        }
        byte bbt[] = new byte[len];
        abt = asc.getBytes();
        int j, k;
        for (int p = 0; p < asc.length() / 2; p++) {
            if ((abt[2 * p] >= '0') && (abt[2 * p] <= '9')) {
                j = abt[2 * p] - '0';
            } else if ((abt[2 * p] >= 'a') && (abt[2 * p] <= 'z')) {
                j = abt[2 * p] - 'a' + 0x0a;
            } else {
                j = abt[2 * p] - 'A' + 0x0a;
            }
            if ((abt[2 * p + 1] >= '0') && (abt[2 * p + 1] <= '9')) {
                k = abt[2 * p + 1] - '0';
            } else if ((abt[2 * p + 1] >= 'a') && (abt[2 * p + 1] <= 'z')) {
                k = abt[2 * p + 1] - 'a' + 0x0a;
            } else {
                k = abt[2 * p + 1] - 'A' + 0x0a;
            }
            int a = (j << 4) + k;
            byte b = (byte) a;
            bbt[p] = b;
        }
        return bbt;
    }

    public static byte getXor(byte[] datas, int start, int end) {
        byte temp = datas[start];
        for (int i = start + 1; i < end; i++) {
            temp ^= datas[i];
        }
        return temp;
    }

    /**
     * 求校验和的算法
     * @param b 需要求校验和的字节数组
     * @return 校验和
     */
    public static byte sumCheck(byte[] b, int start, int end) {
        int sum = 0;
        for (int i = start; i < end; i++) {
            sum = sum + b[i];
        }
        return (byte) (sum & 0xff);
    }

    //字符串转换为ascii
    public static byte[] StrToAsc(String content) {
        try {
            return content.getBytes(StandardCharsets.US_ASCII);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    //ascii转换为string
    public static String AscToStr(byte[] bytes) {
        StringBuffer sbu = new StringBuffer();
        for (byte aByte : bytes) {
            sbu.append(Character.toString((char) aByte));
        }
        return sbu.toString();
    }

    public Class getClassType(String name) {
        return null;
    }

    /**
     * 判断大小端
     * @return true: 小端 / false: 大端
     */
    public boolean isReverse() {
        return this.getClass().getAnnotation(little.class) != null;
    }

    /**
     * 获取字节数组
     */
    public byte[] toBytes() throws Exception {
        return encode(this);
    }

    public Map<String, String> toDecodeHexMapping() throws Exception {
        if (this.decodeByteMapping == null) this.decodeByteMapping = new HashMap<>();
        Map<String, String> mapping = getHex(this.decodeByteMapping);
        if (this.decodeBytes != null) {
            mapping.put("byte[]", Struct.toHex(this.decodeBytes));
        }
        return mapping;
    }

    public Map<String, String> toEncodeHexMapping() throws Exception {
        if (this.encodeBytes == null) this.encode(this);
        if (this.encodeByteMapping == null) this.encodeByteMapping = new HashMap<>();
        Map<String, String> mapping = getHex(this.encodeByteMapping);
        mapping.put("byte[]", Struct.toHex(this.encodeBytes));
        return mapping;
    }

    public Map<String, String> getHex(Map<String, byte[]> bytemapping) throws Exception {
        Map<String, String> map = new LinkedHashMap<>();
        Field[] fields = this.getClass().getFields();
        for (Field field : fields) {
            byte[] bytes = bytemapping.get(field.getName());
            if (bytes != null) {
                map.put(field.getName(), Struct.toHex(bytes));
            }
        }
        return map;
    }

    // 转java对象到数组
    public byte[] encode(Struct entity) throws Exception {
        ByteArrayOutputStream baOs = new ByteArrayOutputStream();
        write(new DataOutputStream(baOs), entity);
        entity.encodeBytes = baOs.toByteArray();
        return entity.encodeBytes;
    }

    /**
     * 写数据到输出流
     *
     * @param dos
     * @param entity
     */
    public void write(DataOutputStream dos, Struct entity) throws Exception {
        if (entity == null) return;
        if (entity.encodeByteMapping == null) entity.encodeByteMapping = new HashMap<>();
        Field[] fields = entity.getClass().getFields();
        EvaluationContext context = new StandardEvaluationContext();
        for (Field field : Objects.requireNonNull(ReflectUtils.removeStaticField(fields))) {
            field.setAccessible(true);

            String name = field.getName();
            Class<?> type = field.getType();
            String typeName = type.getSimpleName();
            if (typeName.equals("Struct")) {
                if (entity.getClassType(name) != null) {
                    type = entity.getClassType(name);
                    typeName = type.getSimpleName();
                } else if (field.get(entity) != null) {
                    type = field.get(entity).getClass();
                    typeName = type.getSimpleName();
                }
            }

            size size = field.getAnnotation(size.class);
            bit bit = field.getAnnotation(bit.class);
            expr expr = field.getAnnotation(expr.class);
            flag flag = field.getAnnotation(flag.class);
            if (size == null && bit == null && expr == null) {
                continue;
            }

            int bited = 0;//已写位数
            int length = 0;//定义的长度
            if (size != null) {
                length = size.value();
                bited += size.value() * 8;
            } else if (bit != null) {
                //按位写方式未实现处理
                throw new RuntimeException("按位写方式未实现处理");
            } else if (expr != null) {
                ExpressionParser parser = new SpelExpressionParser();
                Expression exp = parser.parseExpression(expr.value());
                Integer len = null;
                try {
                    len = CommonUtils.parseInt(exp.getValue(context, entity));
                } catch (Exception e) {
                    len = 0;
                }
                if (len != null) {
                    if (len == -1) continue;
                    length = len;
                    bited += len * 8;
                }
            }
            context.setVariable(name, field.get(entity));

            byte[] bytes = new byte[length];

            if (typeName.equals("int") || typeName.equals("Integer")) {
                dos.write(bytes = convert(length, field.getInt(entity)));
            } else if (typeName.equals("long") || typeName.equals("Long")) {
                dos.write(bytes = convert(length, field.getLong(entity)));
            } else if (typeName.equals("short") || typeName.equals("Short")) {
                dos.write(bytes = convert(length, field.getShort(entity)));
            } else if (typeName.equals("byte") || typeName.equals("Byte")) {
                dos.write(bytes = convert(length, field.getByte(entity)));
            } else if (typeName.equals("String")) {
                String str = (String) field.get(entity);
                if (str == null)
                    str = "";
                str = str.replaceAll("　", " ");

                byte[] bts = null;
                if (flag != null && flag.value().equals("ASCII")) {
                    bts = Struct.StrToAsc(str);
                } else if (flag != null && flag.value().equals("BCD")) {
                    bts = Struct.str2Bcd(str);
                } else {
                    bts = str.getBytes();
                }

                if (length == 0) {//如果长度未设置，以当前实际的字节为准
                    bytes = new byte[bts.length];
                }
                System.arraycopy(bts, 0, bytes, 0, bts.length);
                dos.write(bytes);
            } else if (typeName.equals("byte[]")) {
                byte[] bts = (byte[]) field.get(entity);
                if (bts != null) {
                    if (length == 0) {//如果长度未设置，以当前实际的字节为准
                        bytes = new byte[bts.length];
                    }
                    System.arraycopy(bts, 0, bytes, 0, bts.length);
                    dos.write(bytes);
                }
            } else if (type.isArray()) {
                ByteArrayOutputStream baOs1 = new ByteArrayOutputStream();
                DataOutputStream dos1 = new DataOutputStream(baOs1);
                for (Object object : (Object[]) field.get(entity)) {
                    write(dos1, (Struct) object);
                }
                byte[] bts = baOs1.toByteArray();
                if (length == 0) {//如果长度未设置，以当前实际的字节为准
                    bytes = new byte[bts.length];
                }
                System.arraycopy(bts, 0, bytes, 0, bts.length);
                dos.write(bytes);
            } else {
                byte[] bts = encode((Struct) field.get(entity));
                if (length == 0) {//如果长度未设置，以当前实际的字节为准
                    bytes = new byte[bts.length];
                }
                System.arraycopy(bts, 0, bytes, 0, bts.length);
                dos.write(bytes);
            }
            entity.encodeByteMapping.put(name, bytes);
        }
    }

    public byte[] convert(int size, long value) throws Exception {
        ByteArrayOutputStream baOs = new ByteArrayOutputStream();
        DataOutputStream dos = new DataOutputStream(baOs);
        switch (size) {
            case 1://byte
                dos.write((byte) value);
                break;
            case 2://short
                dos.writeShort(this.isReverse() ? Short.reverseBytes((short) value) : (short) value);
                break;
            case 4://int
                dos.writeInt(this.isReverse() ? Integer.reverseBytes((int) value) : (int) value);
                break;
            case 8://long
                dos.writeLong(this.isReverse() ? Long.reverseBytes((long) value) : (long) value);
                break;
        }
        return baOs.toByteArray();
    }

    public long convertEx(long value, int size) throws Exception {
        switch (size) {
            case 1://byte
                return value;
            case 2://short
                return (this.isReverse() ? Short.reverseBytes((short) value) : (short) value);
            case 4://int
                return (this.isReverse() ? Integer.reverseBytes((int) value) : (int) value);
            case 8://long
                return (this.isReverse() ? Long.reverseBytes((long) value) : (long) value);
        }
        return 0;
    }

    /**
     * 解码： 字节数组 ====>> java对象
     */
    @SuppressWarnings({"unchecked", "rawtypes"})
    public <T extends Struct> T decode(byte[] bytes) throws Exception {
        this.dataBytes = bytes;
        Struct instance = this;
        Class<? extends Struct> cls = this.getClass();
        Field[] fields = cls.getFields();
        if (this.decodeByteMapping == null) instance.decodeByteMapping = new HashMap();
        // spring el表达式
        EvaluationContext context = new StandardEvaluationContext();
        context.setVariable("_", bytes.length);
        int bited = 0;//已读位数
        for (Field field : Objects.requireNonNull(ReflectUtils.removeStaticField(fields))) {
            size size = field.getAnnotation(size.class);
            bit bit = field.getAnnotation(bit.class);
            expr expr = field.getAnnotation(expr.class);
            flag flag = field.getAnnotation(flag.class);
            // 没有size、bit、expr注解的变量不进行解析
            if (size == null && bit == null && expr == null) {
                continue;
            }
            String name = field.getName();
            Class<?> type = field.getType();
            String typeName = type.getSimpleName();
            if (typeName.equals("Struct")) {
                if (instance.getClassType(name) != null) {
                    type = instance.getClassType(name);
                    typeName = type.getSimpleName();
                }
            }
            context.setVariable("__", bytes.length - bited / 8);
            byte[] bts = null;
            if (size != null) {
                bts = new byte[size.value()];
                System.arraycopy(bytes, bited / 8, bts, 0, size.value());
                bited += size.value() * 8;
            } else if (bit != null) {
                int val = 0;
                String strBin = "";
                for (int i = bited; i < bited + bit.value(); i++) {//逐位扫描
                    if ((bytes[i / 8] & (1 << (i % 8))) != 0) {//如果位为1
                        strBin += "1";
                    } else {
                        strBin += "0";
                    }
                    val = Integer.parseInt(strBin, 2);
                }
                byte[] result = new byte[4];
                result[3] = (byte) (val);
                result[2] = (byte) (val >> 8);
                result[1] = (byte) (val >> 16);
                result[0] = (byte) (val >> 24);
                bts = new byte[(int) Math.ceil((double) bit.value() / 8.0)];
                System.arraycopy(result, result.length - bts.length, bts, 0, bts.length);
                bited += bit.value();
            } else if (expr != null) {
                ExpressionParser parser = new SpelExpressionParser();
                Expression exp = parser.parseExpression(expr.value());
                Integer len = CommonUtils.parseInt(exp.getValue(context, instance));
                if (len != null) {
                    if (len == -1) continue;
                    bts = new byte[len];
                    System.arraycopy(bytes, bited / 8, bts, 0, len);
                    bited += len * 8;
                }
            }
            if (bts.length == 0) continue;
            DataInputStream dis = new DataInputStream(new ByteArrayInputStream(bts));
            if (typeName.equals("int") || typeName.equals("Integer")) {
                field.setInt(instance, (int) convertEx(dis.readInt(), 4));
            } else if (typeName.equals("long") || typeName.equals("Long")) {
                field.setLong(instance, convertEx(dis.readLong(), 8));
            } else if (typeName.equals("short") || typeName.equals("Short")) {
                field.setShort(instance, (short) convertEx(dis.readShort(), 2));
            } else if (typeName.equals("byte") || typeName.equals("Byte")) {
                field.setByte(instance, (byte) convertEx(dis.readByte(), 1));
            } else if (typeName.equals("byte[]")) {
                field.set(instance, bts);
            } else if (typeName.equals("String")) {
                String strStr = new String(bts, StandardCharsets.UTF_8);
                if (flag != null && flag.value().equals("BCD")) {
                    strStr = bcd2Str(bts);
                } else if (flag != null && flag.value().equals("ASCII")) {
                    strStr = Struct.AscToStr(bts);
                }
                strStr = strStr.replaceAll("[\u0000]", "");
                field.set(instance, strStr);
            } else if (type.isArray()) {
                byte[] arrayBytes = bts;
                List list = new ArrayList();
                while (arrayBytes.length > 0 && list.size() < 256) {
                    Struct item = decode((Class<? extends Struct>) type.getComponentType(), arrayBytes);
                    list.add(item);
                    arrayBytes = item.unusedBytes;
                }
                Object array = Array.newInstance(type.getComponentType(), list.size());
                for (int i = 0; i < list.size(); i++) {
                    Array.set(array, i, list.get(i));
                }
                field.set(instance, array);
            } else if (type == Struct.class || Struct.class.isAssignableFrom(type)) {
                byte[] arrayBytes = bts;
                Struct item = decode((Class<? extends Struct>) type, arrayBytes);
                field.set(instance, item);
            } else {
                throw new RuntimeException(cls.getSimpleName() + "字段" + field.getName() + "类型未知");
            }
            instance.decodeByteMapping.put(name, bts);
            context.setVariable(name, field.get(instance));
        }
        byte[] useBytes = new byte[bited / 8];
        System.arraycopy(bytes, 0, useBytes, 0, bited / 8);
        instance.decodeBytes = useBytes;
        byte[] unusedBytes = new byte[bytes.length - (bited / 8)];
        if (unusedBytes.length > 0) {
            System.arraycopy(bytes, useBytes.length, unusedBytes, 0, unusedBytes.length);
        }
        instance.unusedBytes = unusedBytes;
        return (T) instance;
    }

    public static class TestMessage {
        public @size(1) byte begin = 0x7e;//起始符
        public @size(2) short type = 0;//消息ID
        public @bit(2) byte retain;//消息体属性>保留
        public @bit(1) byte subpkg;//消息体属性>是否分包,0表示不分包
        public @bit(3) byte encrypt;//消息体属性>加密方式,0表示不加密
        public @bit(10) short length;//消息体长度
        public @size(6)
        @flag("BCD") String number;//手机号码
        public @size(2) short serial;//消息流水号
        public @expr("#subpkg==1?2:0") short pkgs;//分包数
        public @expr("#subpkg==1?2:0") short index;//包序号
        public @expr("#length") byte[] data;//数据部分
        public @size(1) byte verify;//校验码
        public @size(1) byte end = 0x7e;//结束符
    }

}