using System.Text.Json;

namespace Admin.NET.Plugin.AiDOP.Service.S8.Rules;

/// <summary>
/// R3 OUT_OF_RANGE 类规则 params_json 解析结果。internal 可见，供测试覆盖。
/// 兼容两种协议形态：
/// 1. 新协议：measuredValueField / lowerBound / upperBound / lowerBoundField / upperBoundField / objectCodeField / objectIdField / toleranceAbs / toleranceRatio / exceptionTypeCode
/// 2. 旧 G01 兼容：mode=single_threshold / operator=&quot;&gt;&quot;|&quot;&gt;=&quot;|&quot;&lt;&quot;|&quot;&lt;=&quot; / threshold / valueField / objectCodeField / compatAlertRuleCode
/// 字段缺失或非法 JSON：调用方负责降级（evaluator 静默返空命中），不在此抛出业务异常。
/// </summary>
internal sealed class S8OutOfRangeParams
{
    public string? MeasuredValueField { get; set; }
    public string? ObjectCodeField { get; set; }
    public string? ObjectIdField { get; set; }
    public string? LowerBoundField { get; set; }
    public string? UpperBoundField { get; set; }
    public decimal? LowerBound { get; set; }
    public decimal? UpperBound { get; set; }
    public decimal ToleranceAbs { get; set; }
    public decimal ToleranceRatio { get; set; }
    public string? ExceptionTypeCode { get; set; }

    /// <summary>解析 params_json；非法 JSON 抛 <see cref="JsonException"/>，由上游捕获。</summary>
    public static S8OutOfRangeParams Parse(string json)
    {
        using var doc = JsonDocument.Parse(json);
        var root = doc.RootElement;
        var p = new S8OutOfRangeParams();

        // 新协议字段
        if (root.TryGetProperty("measuredValueField", out var v1)) p.MeasuredValueField = v1.GetString();
        if (root.TryGetProperty("objectCodeField", out var v2)) p.ObjectCodeField = v2.GetString();
        if (root.TryGetProperty("objectIdField", out var v3)) p.ObjectIdField = v3.GetString();
        if (root.TryGetProperty("lowerBoundField", out var v4)) p.LowerBoundField = v4.GetString();
        if (root.TryGetProperty("upperBoundField", out var v5)) p.UpperBoundField = v5.GetString();
        if (root.TryGetProperty("lowerBound", out var v6) && v6.ValueKind == JsonValueKind.Number) p.LowerBound = v6.GetDecimal();
        if (root.TryGetProperty("upperBound", out var v7) && v7.ValueKind == JsonValueKind.Number) p.UpperBound = v7.GetDecimal();
        if (root.TryGetProperty("toleranceAbs", out var v8) && v8.ValueKind == JsonValueKind.Number) p.ToleranceAbs = v8.GetDecimal();
        if (root.TryGetProperty("toleranceRatio", out var v9) && v9.ValueKind == JsonValueKind.Number) p.ToleranceRatio = v9.GetDecimal();
        if (root.TryGetProperty("exceptionTypeCode", out var v10)) p.ExceptionTypeCode = v10.GetString();

        // G01 兼容：valueField → measuredValueField
        if (string.IsNullOrWhiteSpace(p.MeasuredValueField)
            && root.TryGetProperty("valueField", out var legacyVal))
            p.MeasuredValueField = legacyVal.GetString();

        // G01 兼容：mode=single_threshold + operator + threshold → upperBound 或 lowerBound
        if (root.TryGetProperty("mode", out var modeEl)
            && string.Equals(modeEl.GetString(), "single_threshold", StringComparison.OrdinalIgnoreCase)
            && root.TryGetProperty("operator", out var opEl)
            && root.TryGetProperty("threshold", out var thrEl)
            && thrEl.ValueKind == JsonValueKind.Number)
        {
            var op = opEl.GetString()?.Trim();
            var thr = thrEl.GetDecimal();
            // operator '>' 或 '>=' → measured 超过 threshold 命中 → 等价 upperBound=threshold
            // operator '<' 或 '<=' → measured 低于 threshold 命中 → 等价 lowerBound=threshold
            if (op == ">" || op == ">=") p.UpperBound ??= thr;
            else if (op == "<" || op == "<=") p.LowerBound ??= thr;
        }

        return p;
    }
}