using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace OMS.NET.Instructs
{
    /// <summary>
    /// 声明json转换的命名策略
    /// </summary>
    class InstructNamingPolicy : JsonNamingPolicy
    {
        public override string ConvertName(string name)
        {
            return Convert(name);
        }

        public static string Convert(string name) => name switch
        {
            "Type" => "type",
            "Class" => "class",
            "Conveyor" => "conveyor",
            "Time" => "time",
            "Data" => "data",
            _ => name,
        };
    }

    /// <summary>
    /// 实现依据type和class的值决定反序列化的对象类型
    /// </summary>
    class InstructConverter : JsonConverter<Instruct>
    {
        public override Instruct Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
        {
            using JsonDocument doc = JsonDocument.ParseValue(ref reader);
            JsonElement root = doc.RootElement;
            //Console.WriteLine(root.GetRawText());
            if (root.TryGetProperty("type", out JsonElement typeProperty))
            {
                string? typeValue = typeProperty.GetString();
                string? classValue = root.TryGetProperty("class", out JsonElement classProperty) ? classProperty.GetString() : null;
                Instruct? instruct = typeValue switch
                {
                    //实现新指令需在这里添加反序列化类型，限定为客户端发过来的指令类型
                    "get_publickey" => JsonSerializer.Deserialize<GetPublickeyInstruct>(root.GetRawText(), options),
                    "get_serverImg" => JsonSerializer.Deserialize<GetServerImgInstruct>(root.GetRawText(), options),
                    "get_serverConfig" => JsonSerializer.Deserialize<GetServerConfigInstruct>(root.GetRawText(), options),
                    "login" => JsonSerializer.Deserialize<LoginInstruct>(root.GetRawText(), options),
                    "test" => JsonSerializer.Deserialize<TestInstruct>(root.GetRawText(), options),
                    "get_userData" => JsonSerializer.Deserialize<GetUserDataInstruct>(root.GetRawText(), options),
                    "get_presence" => JsonSerializer.Deserialize<GetPresenceInstruct>(root.GetRawText(), options),
                    "get_mapData" => JsonSerializer.Deserialize<GetMapDataInstruct>(root.GetRawText(), options),
                    "get_mapLayer" => JsonSerializer.Deserialize<GetMapLayerInstruct>(root.GetRawText(), options),
                    "ping" => JsonSerializer.Deserialize<PingInstuct>(root.GetRawText(), options),

                    //广播指令
                    "broadcast" => classValue switch
                    {
                        //广播指令继承结构
                        "point" => JsonSerializer.Deserialize<AddElementBroadcastInstruct>(root.GetRawText(), options),
                        "line" => JsonSerializer.Deserialize<AddElementBroadcastInstruct>(root.GetRawText(), options),
                        "area" => JsonSerializer.Deserialize<AddElementBroadcastInstruct>(root.GetRawText(), options),
                        "curve" => JsonSerializer.Deserialize<AddElementBroadcastInstruct>(root.GetRawText(), options),
                        _ => JsonSerializer.Deserialize<Instruct>(root.GetRawText(), options)
                    },
                    _ => null
                } ?? throw new JsonException($"{typeValue} 反序列化失败");
                return instruct;
            }
            else
            {
                throw new JsonException("type property not found");
            }
        }

        public override void Write(Utf8JsonWriter writer, Instruct value, JsonSerializerOptions options)
        {
            //JsonSerializer.Serialize(writer, (object)value, options); 这个在Data是对象时导致了无限递归调用
            writer.WriteStartObject();
            writer.WriteString(InstructNamingPolicy.Convert(nameof(Instruct.Type)), value.Type);
            if (value.Class != null)
            {
                writer.WriteString(InstructNamingPolicy.Convert(nameof(Instruct.Class)), value.Class);
            }
            if (value.Conveyor != null)
            {
                writer.WriteString(InstructNamingPolicy.Convert(nameof(Instruct.Conveyor)), value.Conveyor);
            }
            if (value.Time != null)
            {
                writer.WriteString(InstructNamingPolicy.Convert(nameof(Instruct.Time)), value.Time);
            }
            if (value.Data != null)
            {
                writer.WritePropertyName(InstructNamingPolicy.Convert(nameof(Instruct.Data)));
                JsonSerializer.Serialize(writer, value.Data, value.Data.GetType(), options);
            }
            writer.WriteEndObject();
        }
    }

    public class Instruct
    {
        public static readonly JsonSerializerOptions options = new()
        {
            ReadCommentHandling = JsonCommentHandling.Skip, //允许注释
            AllowTrailingCommas = true,//允许尾随逗号
            PropertyNamingPolicy = new InstructNamingPolicy(), // 属性名为定制转换
            DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull, // 忽略 null 值
            WriteIndented = true, // 美化输出
            //PropertyNameCaseInsensitive = true,//属性名忽略大小写
            Converters = { new InstructConverter() },
        };
        public string Type { get; set; }
        public string? Class { get; set; }
        public string? Conveyor { get; set; }
        public string? Time { get; set; }
        public dynamic? Data { get; set; }

        [JsonIgnore]
        public bool IsResponse { get; set; } = false;
        [JsonIgnore]
        public bool IsBroadcast { get; set; } = false;
        [JsonIgnore]
        public List<Instruct> ResponseOrBroadcastInstructs { get; set; } = new();

        public Instruct()
        {
            this.Type = "";
        }

        /// <summary>
        /// 指令处理逻辑
        /// </summary>
        /// <returns>将耗时任务交给Task以不阻塞单个连接的多个请求</returns>
        public virtual Task Handler(string wsid)
        {
            return Task.CompletedTask;
        }

        public async Task HandlerAndMeasure(string wsid)
        {
            Stopwatch stopWatch = new();
            stopWatch.Start();
            await Handler(wsid);
            stopWatch.Stop();
            GlobalArea.Log.Debug($"处理{this.GetType()}耗时：{stopWatch.ElapsedMilliseconds}ms");
        }

        public string ToJsonString()
        {
            return JsonSerializer.Serialize(this, options);
        }

        public static Instruct? JsonStringParse(string jsonString)
        {
            try
            {
                return JsonSerializer.Deserialize<Instruct>(jsonString, options);
            }
            catch (Exception ex)
            {
                GlobalArea.Log.Error(ex.Message);
                return null;
            }
        }
    }
}