package com.ruoyi.mill.protocol;

import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.Map;

/**
 * 新协议字段定义
 * 报文格式：[4字节LE ID][4字节LE 数据长度][数据体]
 * 数据体：每个字段小端存储
 */
public class MillDataField {

    public enum DataType {
        I4,  // 4字节有符号整数（小端）
        I2,  // 2字节有符号整数（小端）
        F4   // 4字节IEEE-754单精度浮点（小端）
    }

    private final String name;
    private final String description;
    private final String unit;
    private final DataType type;
    // I4类型可含位字段：index→bitName，index→bitDescription
    private final Map<Integer, String> bitNames;
    private final Map<Integer, String> bitDescriptions;

    private MillDataField(String name, String description, String unit, DataType type,
                          Map<Integer, String> bitNames, Map<Integer, String> bitDescriptions) {
        this.name = name;
        this.description = description;
        this.unit = unit;
        this.type = type;
        this.bitNames = bitNames != null ? Collections.unmodifiableMap(bitNames) : Collections.emptyMap();
        this.bitDescriptions = bitDescriptions != null ? Collections.unmodifiableMap(bitDescriptions) : Collections.emptyMap();
    }

    public static MillDataField i4(String name, String description, String unit) {
        return new MillDataField(name, description, unit, DataType.I4, null, null);
    }

    public static MillDataField i4WithBits(String name, String description,
                                            Map<Integer, String> bitNames,
                                            Map<Integer, String> bitDescriptions) {
        return new MillDataField(name, description, "", DataType.I4, bitNames, bitDescriptions);
    }

    public static MillDataField i2(String name, String description, String unit) {
        return new MillDataField(name, description, unit, DataType.I2, null, null);
    }

    public static MillDataField f4(String name, String description, String unit) {
        return new MillDataField(name, description, unit, DataType.F4, null, null);
    }

    public int byteLength() {
        return type == DataType.I2 ? 2 : 4;
    }

    public boolean hasBits() {
        return !bitNames.isEmpty();
    }

    public String getName()                        { return name; }
    public String getDescription()                 { return description; }
    public String getUnit()                        { return unit; }
    public DataType getType()                      { return type; }
    public Map<Integer, String> getBitNames()      { return bitNames; }
    public Map<Integer, String> getBitDescriptions() { return bitDescriptions; }

    /** 构建位字段Map的便捷方法 */
    public static Map<Integer, String> bits(Object... indexAndName) {
        Map<Integer, String> map = new LinkedHashMap<>();
        for (int i = 0; i + 1 < indexAndName.length; i += 2) {
            map.put((Integer) indexAndName[i], (String) indexAndName[i + 1]);
        }
        return map;
    }
}