using System.Reflection;
using System.Xml;
using System.Xml.Serialization;
using NewLife.Reflection;

namespace NewLife.Serialization;

/// <summary>Xml复合对象处理器</summary>
public class XmlComposite : XmlHandlerBase
{
    /// <summary>实例化</summary>
    public XmlComposite()
    {
        Priority = 100;
    }

    /// <summary>写入对象</summary>
    /// <param name="value">目标对象</param>
    /// <param name="type">类型</param>
    /// <returns></returns>
    public override Boolean Write(Object? value, Type type)
    {
        if (value == null) return false;

        // 不支持基本类型
        if (type.IsBaseType()) return false;

        var ms = GetMembers(type);
        WriteLog("XmlWrite {0} 成员{1}个", type.Name, ms.Count);

        Host.Hosts.Push(value);

        //var xml = Host as Xml;
        //xml.WriteStart(type);
        try
        {
            // 获取成员
            foreach (var member in GetMembers(type))
            {
                var mtype = member.GetMemberType();
                Host.Member = member;

                var name = SerialHelper.GetName(member);
                var v = value.GetValue(member);
                WriteLog("    {0}.{1} {2}", type.Name, member.Name, v);

                if (!Host.Write(v, name, mtype)) return false;
            }
        }
        finally
        {
            //xml.WriteEnd();

            Host.Hosts.Pop();
        }

        return true;
    }

    /// <summary>尝试读取</summary>
    /// <param name="type"></param>
    /// <param name="value"></param>
    /// <returns></returns>
    public override Boolean TryRead(Type type, ref Object? value)
    {
        if (type == null)
        {
            if (value == null) return false;
            type = value.GetType();
        }

        // 不支持基本类型
        if (type.IsBaseType()) return false;
        // 不支持基类不是Object的特殊类型
        //if (type.BaseType != typeof(Object)) return false;
        if (!type.As<Object>()) return false;

        var reader = Host.GetReader();
        var xml = Host as Xml;
        if (xml == null) return false;

        // 判断类名是否一致
        var name = xml.CurrentName;
        if (!CheckName(name, type)) return false;

        var ms = GetMembers(type);
        WriteLog("XmlRead {0} 成员{1}个", type.Name, ms.Count);
        var dic = ms.ToDictionary(e => SerialHelper.GetName(e), e => e);

        value ??= type.CreateInstance();
        if (value == null) return false;

        Host.Hosts.Push(value);

        try
        {
            if (reader.NodeType == XmlNodeType.Attribute)
            {
                foreach (var item in dic)
                {
                    var member = item.Value;
                    var v = reader.GetAttribute(item.Key);
                    WriteLog("    {0}.{1} {2}", type.Name, member.Name, v);

                    value.SetValue(member, v);
                }
            }
            else
            {
                // 获取成员
                var member = ms[0];
                while (reader.NodeType != XmlNodeType.None && reader.IsStartElement())
                {
                    // 找到匹配的元素，否则跳过
                    if (!dic.TryGetValue(reader.Name, out member) || !member.CanWrite)
                    {
                        reader.Skip();
                        continue;
                    }

                    var mtype = member.GetMemberType();
                    if (mtype == null) continue;

                    Host.Member = member;

                    var v = value.GetValue(member);
                    WriteLog("    {0}.{1} {2}", type.Name, member.Name, v);

                    if (!Host.TryRead(mtype, ref v)) return false;

                    value.SetValue(member, v);
                }
            }
        }
        finally
        {
            Host.Hosts.Pop();
        }

        return true;
    }

    #region 辅助
    private Boolean CheckName(String? name, Type type)
    {
        if (type.Name.EqualIgnoreCase(name)) return true;

        // 当前正在序列化的成员
        var mb = Host.Member;
        if (mb != null)
        {
            var elm = mb.GetCustomAttribute<XmlElementAttribute>();
            if (elm != null) return elm.ElementName.EqualIgnoreCase(name);

            if (mb.Name.EqualIgnoreCase(name)) return true;
        }

        // 检查类型的Root
        var att = type.GetCustomAttribute<XmlRootAttribute>();
        if (att != null) return att.ElementName.EqualIgnoreCase(name);

        return false;
    }
    #endregion

    #region 获取成员
    /// <summary>获取成员</summary>
    /// <param name="type"></param>
    /// <returns></returns>
    protected virtual List<PropertyInfo> GetMembers(Type type) => type.GetProperties(true).ToList();
    #endregion
}