using System.Collections;
using Fake.Application;
using Fake.Application.Dtos;
using Fake.AspNetCore.ExceptionHandling;
using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;
using Oms.Application.Dtos.Orders;

namespace SimpleAdmin.Api.ExceptionHandling;

/// <summary>
/// 在 Fake 默认异常转换之上，把草稿已落库失败的结构化信息写入 Details，并清理 msg 中的机器标记。
/// </summary>
public class OmsException2ResponseConverter : IException2ResponseConverter
{
    private static readonly JsonSerializerSettings JsonSettings = new()
    {
        ContractResolver = new CamelCasePropertyNamesContractResolver(),
        NullValueHandling = NullValueHandling.Ignore,
    };

    private const string DraftSavedMarkerPrefix = " [[omsDraft:";

    private readonly DefaultException2ResponseConverter _inner;

    public OmsException2ResponseConverter(DefaultException2ResponseConverter inner)
    {
        _inner = inner;
    }

    public ApplicationExceptionResponse Convert(Exception exception, FakeExceptionHandlingOptions options)
    {
        var response = _inner.Convert(exception, options);
        response.Message = StripDraftSavedMarker(response.Message);

        if (TryBuildDraftFailData(exception, out var failData))
        {
            if (string.IsNullOrWhiteSpace(response.Message))
            {
                response.Message = failData.Reason;
            }

            response.Details = JsonConvert.SerializeObject(failData, JsonSettings);
        }

        return response;
    }

    private static bool TryBuildDraftFailData(Exception exception, out OrderParcelDraftFailData failData)
    {
        failData = new OrderParcelDraftFailData();
        if (exception is not BusinessException business)
        {
            return false;
        }

        if (business.Data[OrderParcelDraftFailData.DataKey] is string json
            && !string.IsNullOrWhiteSpace(json))
        {
            try
            {
                var parsed = JsonConvert.DeserializeObject<OrderParcelDraftFailData>(json);
                if (parsed != null && parsed.DraftSaved && parsed.OrderId > 0)
                {
                    failData = parsed;
                    return true;
                }
            }
            catch
            {
                // fall through to key-based parse
            }
        }

        if (!HasDraftSavedFlag(business.Data))
        {
            // 兼容旧客户端：仅从 message 尾部标记解析
            return TryParseMarker(business.Message, out failData);
        }

        failData.DraftSaved = true;
        failData.OrderId = ToInt(business.Data["orderId"] ?? business.Data["OrderId"]);
        failData.ServiceNo = ToStringValue(business.Data["serviceNo"] ?? business.Data["ServiceNo"]);
        failData.Reason = StripDraftSavedMarker(business.Message);
        failData.ErrorCode = OrderParcelDraftFailData.ErrorCodeValue;
        return failData.OrderId > 0;
    }

    private static bool HasDraftSavedFlag(IDictionary data)
    {
        if (data.Contains("draftSaved") && IsTruthy(data["draftSaved"])) return true;
        if (data.Contains("DraftSaved") && IsTruthy(data["DraftSaved"])) return true;
        return false;
    }

    private static bool TryParseMarker(string? message, out OrderParcelDraftFailData failData)
    {
        failData = new OrderParcelDraftFailData();
        if (string.IsNullOrEmpty(message)) return false;
        var idx = message.IndexOf(DraftSavedMarkerPrefix, StringComparison.Ordinal);
        if (idx < 0) return false;
        var jsonStart = idx + DraftSavedMarkerPrefix.Length;
        var jsonEnd = message.LastIndexOf("]]", StringComparison.Ordinal);
        if (jsonEnd <= jsonStart) return false;
        try
        {
            var parsed = JsonConvert.DeserializeObject<OrderParcelDraftFailData>(message[jsonStart..jsonEnd]);
            if (parsed == null || !parsed.DraftSaved || parsed.OrderId <= 0) return false;
            parsed.Reason = message[..idx].TrimEnd();
            parsed.ErrorCode = OrderParcelDraftFailData.ErrorCodeValue;
            failData = parsed;
            return true;
        }
        catch
        {
            return false;
        }
    }

    private static string StripDraftSavedMarker(string? message)
    {
        if (string.IsNullOrEmpty(message)) return string.Empty;
        var idx = message.IndexOf(DraftSavedMarkerPrefix, StringComparison.Ordinal);
        return idx < 0 ? message : message[..idx].TrimEnd();
    }

    private static bool IsTruthy(object? value) =>
        value is true
        || (value is bool b && b)
        || string.Equals(global::System.Convert.ToString(value), "true", StringComparison.OrdinalIgnoreCase)
        || string.Equals(global::System.Convert.ToString(value), "1", StringComparison.OrdinalIgnoreCase);

    private static int ToInt(object? value)
    {
        if (value == null) return 0;
        return int.TryParse(global::System.Convert.ToString(value), out var n) ? n : 0;
    }

    private static string ToStringValue(object? value) =>
        global::System.Convert.ToString(value)?.Trim() ?? string.Empty;
}