using System.Globalization;
using System.Text.Json;
using System.Text.RegularExpressions;

namespace FoodLabeling.Application.Helpers;

/// <summary>
/// Print Log「Expiry Date」：从打印任务 JSON 解析到期日期时间（优先已渲染的 __previewFormatted）。
/// </summary>
public static class ReportsPrintLogExpiryHelper
{
    private static readonly string[] RootExpiryKeys =
    {
        "expiryDate",
        "expiry",
        "expirationDate",
        "bestBeforeDate",
        "useByDate"
    };

    private static readonly HashSet<string> OffsetUnits = new(StringComparer.Ordinal)
    {
        "Minutes",
        "Hours",
        "Days",
        "Weeks",
        "Months (30 Day)",
        "Years"
    };

    private static readonly Regex ExpiryNamePattern = new(
        @"(durationdate|duration_date|duration\s*date|expirydate|expiry_date|expiry\s*date|expirationdate|expiration_date|usebydate|use_by)",
        RegexOptions.IgnoreCase | RegexOptions.CultureInvariant | RegexOptions.Compiled);

    private static readonly Regex ExpiryTimeNamePattern = new(
        @"(durationtime|duration_time|duration\s*time|expirytime|expiry_time|expiry\s*time|usebytime|use_by_time)",
        RegexOptions.IgnoreCase | RegexOptions.CultureInvariant | RegexOptions.Compiled);

    private static readonly Regex ExcludeNamePattern = new(
        @"(currentdate|currenttime|prepped|prepdate|prepon|labelname|durationdate2|duration_date_2|durationdate_2|duration\s*date\s*2)",
        RegexOptions.IgnoreCase | RegexOptions.CultureInvariant | RegexOptions.Compiled);

    /// <summary>解析并格式化为 Print Log Expiration 列展示（含日期与时间）。</summary>
    public static string ExtractFormattedExpiryText(
        string? printInputJson,
        string? renderTemplateJson = null,
        DateTime? baseTime = null,
        DateTime? printedAt = null)
    {
        var reference = baseTime ?? printedAt ?? DateTime.Now;
        if (TryResolveExpiryDateTime(printInputJson, renderTemplateJson, reference, out var resolved))
        {
            return ReportsDateTimeDisplayHelper.FormatExpiryDateTime(resolved);
        }

        var raw = ExtractExpiryText(printInputJson, reference);
        if (string.Equals(raw, "无", StringComparison.Ordinal) && !string.IsNullOrWhiteSpace(renderTemplateJson))
        {
            raw = ExtractExpiryText(renderTemplateJson, reference);
        }

        return ReportsDateTimeDisplayHelper.FormatExpiryDisplay(raw, reference);
    }

    /// <summary>兼容旧调用：仅 PrintInputJson。</summary>
    public static string ExtractFormattedExpiryText(string? printInputJson) =>
        ExtractFormattedExpiryText(printInputJson, null, null, null);

    private static bool TryResolveExpiryDateTime(
        string? printInputJson,
        string? renderTemplateJson,
        DateTime reference,
        out DateTime expiry)
    {
        expiry = default;
        foreach (var json in new[] { printInputJson, renderTemplateJson })
        {
            if (TryResolveExpiryDateTimeFromTemplateJson(json, reference, out expiry))
            {
                return true;
            }
        }

        return false;
    }

    private static bool TryResolveExpiryDateTimeFromTemplateJson(string? json, DateTime reference, out DateTime expiry)
    {
        expiry = default;
        if (string.IsNullOrWhiteSpace(json))
        {
            return false;
        }

        try
        {
            using var doc = JsonDocument.Parse(json);
            if (doc.RootElement.ValueKind != JsonValueKind.Object)
            {
                return false;
            }

            var root = doc.RootElement;
            if (!TryGetProperty(root, "elements", out var elements) || elements.ValueKind != JsonValueKind.Array)
            {
                return false;
            }

            if (!TryFindBestElement(elements, isDateElement: true, out var dateElement))
            {
                return false;
            }

            if (!TryResolveElementDateTime(dateElement, reference, out var datePart))
            {
                return false;
            }

            expiry = datePart;
            if (HasMeaningfulTime(datePart))
            {
                return true;
            }

            if (TryFindBestElement(elements, isDateElement: false, out var timeElement) &&
                TryResolveElementDateTime(timeElement, reference, out var timePart))
            {
                expiry = new DateTime(
                    datePart.Year,
                    datePart.Month,
                    datePart.Day,
                    timePart.Hour,
                    timePart.Minute,
                    0);
                return true;
            }

            return true;
        }
        catch
        {
            return false;
        }
    }

    private static bool TryFindBestElement(JsonElement elements, bool isDateElement, out JsonElement bestElement)
    {
        bestElement = default;
        var bestScore = 0;
        var bestOrder = int.MinValue;
        var found = false;

        foreach (var el in elements.EnumerateArray())
        {
            if (el.ValueKind != JsonValueKind.Object)
            {
                continue;
            }

            var score = isDateElement ? ScoreExpiryDateElement(el) : ScoreExpiryTimeElement(el);
            if (score <= 0)
            {
                continue;
            }

            var order = TryGetIntProperty(el, "orderNum", "OrderNum") ?? 0;
            if (score > bestScore || (score == bestScore && order > bestOrder))
            {
                bestScore = score;
                bestOrder = order;
                bestElement = el;
                found = true;
            }
        }

        return found;
    }

    private static bool TryResolveElementDateTime(JsonElement el, DateTime reference, out DateTime result)
    {
        result = default;
        var display = ResolveElementDisplayText(el, reference);
        if (string.IsNullOrWhiteSpace(display))
        {
            return false;
        }

        return ReportsDateTimeDisplayHelper.TryParseExpiryDateTime(display.Trim(), reference, out result);
    }

    private static string? ResolveElementDisplayText(JsonElement el, DateTime reference)
    {
        if (!TryGetProperty(el, "config", out var cfg) && !TryGetProperty(el, "Config", out cfg))
        {
            return null;
        }

        var rawText = GetStringProperty(cfg, "text", "Text").Trim();
        var formatText = GetStringProperty(cfg, "format", "Format").Trim();
        var type = GetStringProperty(el, "type", "Type").Trim().ToUpperInvariant();

        var fromOffset = TryResolveOffsetDisplay(el, cfg, reference, rawText)
                         ?? TryResolveOffsetDisplay(el, cfg, reference, formatText);
        if (!string.IsNullOrWhiteSpace(fromOffset))
        {
            return fromOffset;
        }

        if (!string.IsNullOrWhiteSpace(rawText) && IsLikelyResolvedDateTimeLiteral(rawText))
        {
            return rawText;
        }

        if (type is "DATE" or "TIME" or "DURATION")
        {
            var off = ReadOffsetFromElementConfig(el, cfg, type);
            if (off.HasValue)
            {
                var resolved = ApplyOffsetToDate(reference, off.Value.amount, off.Value.unit);
                return type switch
                {
                    "TIME" => resolved.ToString("HH:mm", CultureInfo.InvariantCulture),
                    "DATE" => FormatDateByElementPreset(el, cfg, resolved),
                    _ => $"{off.Value.amount} {off.Value.unit}".Trim()
                };
            }
        }

        return string.IsNullOrWhiteSpace(rawText) ? null : rawText;
    }

    private static string? TryResolveOffsetDisplay(
        JsonElement el,
        JsonElement cfg,
        DateTime reference,
        string raw)
    {
        if (string.IsNullOrWhiteSpace(raw))
        {
            return null;
        }

        if (!TryParseOffsetStored(raw, out var offset))
        {
            return null;
        }

        var amount = NormalizeOffsetAmount(offset.value);
        if (amount is null)
        {
            return null;
        }

        var type = GetStringProperty(el, "type", "Type").Trim().ToUpperInvariant();
        var resolved = ApplyOffsetToDate(reference, amount.Value, offset.unit);
        return type switch
        {
            "TIME" => resolved.ToString("HH:mm", CultureInfo.InvariantCulture),
            "DATE" => FormatDateByElementPreset(el, cfg, resolved),
            "DURATION" => $"{amount.Value} {offset.unit}".Trim(),
            _ => FormatDateByElementPreset(el, cfg, resolved)
        };
    }

    private static string FormatDateByElementPreset(JsonElement el, JsonElement cfg, DateTime date)
    {
        var type = GetStringProperty(el, "type", "Type").Trim().ToUpperInvariant();
        if (type == "TIME")
        {
            return date.ToString("HH:mm", CultureInfo.InvariantCulture);
        }

        var inputType = GetStringProperty(cfg, "inputType", "InputType").Trim().ToLowerInvariant();
        var format = GetStringProperty(cfg, "format", "Format").Trim();
        if (string.IsNullOrWhiteSpace(format) || OffsetUnits.Contains(format) || IsLikelyResolvedDateTimeLiteral(format))
        {
            format = inputType == "datetime" ? "YYYY-MM-DD HH:mm" : "MM/DD/YY";
        }

        return FormatDateByPreset(format, date);
    }

    private static string FormatDateByPreset(string format, DateTime date)
    {
        var yyyy = date.Year.ToString(CultureInfo.InvariantCulture);
        var yy = yyyy[^2..];
        var mm = date.Month.ToString("00", CultureInfo.InvariantCulture);
        var dd = date.Day.ToString("00", CultureInfo.InvariantCulture);
        var hh = date.Hour.ToString("00", CultureInfo.InvariantCulture);
        var min = date.Minute.ToString("00", CultureInfo.InvariantCulture);

        return format switch
        {
            "DD/MM/YYYY" => $"{dd}/{mm}/{yyyy}",
            "MM/DD/YYYY" => $"{mm}/{dd}/{yyyy}",
            "DD/MM/YY" => $"{dd}/{mm}/{yy}",
            "MM/DD/YY" => $"{mm}/{dd}/{yy}",
            "MM/YY" => $"{mm}/{yy}",
            "MM/DD" => $"{mm}/{dd}",
            "MM" => mm,
            "DD" => dd,
            "YY" => yy,
            "YYYY-MM-DD HH:mm" => $"{yyyy}-{mm}-{dd} {hh}:{min}",
            _ => format
                .Replace("YYYY", yyyy, StringComparison.Ordinal)
                .Replace("YY", yy, StringComparison.Ordinal)
                .Replace("MM", mm, StringComparison.Ordinal)
                .Replace("DD", dd, StringComparison.Ordinal)
                .Replace("HH", hh, StringComparison.Ordinal)
                .Replace("mm", min, StringComparison.Ordinal)
        };
    }

    private static (int amount, string unit)? ReadOffsetFromElementConfig(JsonElement el, JsonElement cfg, string type)
    {
        if (type == "DURATION")
        {
            var unit = GetStringProperty(cfg, "format", "Format").Trim();
            if (string.IsNullOrWhiteSpace(unit) || !OffsetUnits.Contains(unit))
            {
                unit = "Days";
            }

            var rawV = GetNumberProperty(cfg, "durationValue", "value", "offsetDays", "DurationValue", "Value", "OffsetDays");
            return (rawV ?? 0, unit);
        }

        var offsetDays = GetNumberProperty(cfg, "offsetDays", "OffsetDays");
        if (offsetDays.HasValue)
        {
            return (offsetDays.Value, "Days");
        }

        var fmt = GetStringProperty(cfg, "format", "Format").Trim();
        if (!string.IsNullOrWhiteSpace(fmt) && OffsetUnits.Contains(fmt))
        {
            var rawV = GetNumberProperty(cfg, "durationValue", "value", "DurationValue", "Value");
            return (rawV ?? 0, fmt);
        }

        return null;
    }

    private static DateTime ApplyOffsetToDate(DateTime baseTime, int amount, string unit)
    {
        var d = baseTime;
        switch (unit)
        {
            case "Minutes":
                return d.AddMinutes(amount);
            case "Hours":
                return d.AddHours(amount);
            case "Days":
                return d.AddDays(amount);
            case "Weeks":
                return d.AddDays(amount * 7);
            case "Months (30 Day)":
                return d.AddDays(amount * 30);
            case "Years":
                return d.AddYears(amount);
            default:
                return d.AddDays(amount);
        }
    }

    private static bool TryParseOffsetStored(string raw, out (string unit, string value) offset)
    {
        offset = default;
        var t = raw.Trim();
        if (!t.StartsWith('{'))
        {
            return false;
        }

        try
        {
            using var doc = JsonDocument.Parse(t);
            if (doc.RootElement.ValueKind != JsonValueKind.Object)
            {
                return false;
            }

            var root = doc.RootElement;
            var unit = GetStringProperty(root, "unit", "Unit").Trim();
            var value = GetStringProperty(root, "value", "Value");
            if (string.IsNullOrWhiteSpace(unit) || !OffsetUnits.Contains(unit))
            {
                return false;
            }

            offset = (unit, value);
            return true;
        }
        catch
        {
            return false;
        }
    }

    private static int? NormalizeOffsetAmount(string valueRaw)
    {
        var t = valueRaw.Trim();
        if (t.Length == 0)
        {
            return 0;
        }

        if (int.TryParse(t, NumberStyles.Integer, CultureInfo.InvariantCulture, out var n))
        {
            return n;
        }

        if (double.TryParse(t, NumberStyles.Float, CultureInfo.InvariantCulture, out var d) && double.IsFinite(d))
        {
            return (int)d;
        }

        return null;
    }

    private static bool IsLikelyResolvedDateTimeLiteral(string raw)
    {
        var t = raw.Trim();
        if (t.Length == 0 || t.StartsWith('{'))
        {
            return false;
        }

        if (OffsetUnits.Contains(t))
        {
            return false;
        }

        if (Regex.IsMatch(t, @"^\d{4}-\d{2}-\d{2}"))
        {
            return true;
        }

        if (Regex.IsMatch(t, @"^\d{1,2}/\d{1,2}/\d{2,4}"))
        {
            return true;
        }

        if (Regex.IsMatch(t, @"^\d{1,2}:\d{2}(:\d{2})?$"))
        {
            return true;
        }

        return false;
    }

    private static bool HasMeaningfulTime(DateTime dt) =>
        dt.Hour != 0 || dt.Minute != 0;

    /// <summary>
    /// 解析保质期展示文本；无法解析时返回「无」。
    /// </summary>
    public static string ExtractExpiryText(string? printInputJson, DateTime anchor)
    {
        if (string.IsNullOrWhiteSpace(printInputJson))
        {
            return "无";
        }

        try
        {
            using var doc = JsonDocument.Parse(printInputJson);
            if (doc.RootElement.ValueKind != JsonValueKind.Object)
            {
                return "无";
            }

            var root = doc.RootElement;

            if (TryGetRootExpiryText(root, anchor, out var fromRoot))
            {
                return fromRoot;
            }

            if (TryGetProperty(root, "elements", out var elements) && elements.ValueKind == JsonValueKind.Array)
            {
                if (TryExtractNamedDurationExpiry(elements, anchor, out var fromNamed))
                {
                    return fromNamed;
                }

                if (TryExtractFromElements(elements, anchor, out var fromElements))
                {
                    return fromElements;
                }
            }
        }
        catch
        {
            return "无";
        }

        return "无";
    }

    private static DateTime ResolveAnchor(DateTime? baseTime, DateTime? printedAt, string? printInputJson)
    {
        if (baseTime.HasValue && baseTime.Value != DateTime.MinValue)
        {
            return baseTime.Value;
        }

        if (printedAt.HasValue && printedAt.Value != DateTime.MinValue)
        {
            return printedAt.Value;
        }

        if (!string.IsNullOrWhiteSpace(printInputJson))
        {
            try
            {
                using var doc = JsonDocument.Parse(printInputJson);
                if (doc.RootElement.ValueKind == JsonValueKind.Object)
                {
                    foreach (var key in new[] { "baseTime", "BaseTime" })
                    {
                        if (!TryGetProperty(doc.RootElement, key, out var v))
                        {
                            continue;
                        }

                        if (v.ValueKind == JsonValueKind.String &&
                            DateTime.TryParse(
                                v.GetString(),
                                CultureInfo.InvariantCulture,
                                DateTimeStyles.RoundtripKind | DateTimeStyles.AssumeLocal,
                                out var parsed))
                        {
                            return parsed;
                        }
                    }
                }
            }
            catch
            {
                // ignore
            }
        }

        return DateTime.Now;
    }

    private static bool IsMissingExpiry(string? raw) =>
        string.IsNullOrWhiteSpace(raw) || string.Equals(raw.Trim(), "无", StringComparison.Ordinal);

    private static bool TryGetRootExpiryText(JsonElement root, DateTime anchor, out string text)
    {
        text = "无";
        foreach (var prop in root.EnumerateObject())
        {
            var key = prop.Name.Trim();
            if (!RootExpiryKeys.Any(k => key.Equals(k, StringComparison.OrdinalIgnoreCase)))
            {
                continue;
            }

            if (TryFormatJsonValueAsExpiryText(prop.Value, anchor, out text))
            {
                return true;
            }
        }

        return false;
    }

    /// <summary>优先按 elementName 合并 durationdate + durationtime（App 打印快照常见结构）。</summary>
    private static bool TryExtractNamedDurationExpiry(JsonElement elements, DateTime anchor, out string text)
    {
        text = "无";
        string? datePart = null;
        string? timePart = null;

        foreach (var el in elements.EnumerateArray())
        {
            if (el.ValueKind != JsonValueKind.Object)
            {
                continue;
            }

            var name = GetStringProperty(el, "elementName", "ElementName").Trim();
            if (name.Equals("durationdate", StringComparison.OrdinalIgnoreCase))
            {
                datePart = GetElementConfigDisplayText(el, anchor);
            }
            else if (name.Equals("durationtime", StringComparison.OrdinalIgnoreCase))
            {
                timePart = GetElementConfigDisplayText(el, anchor);
            }
        }

        if (string.IsNullOrWhiteSpace(datePart) || IsMissingExpiry(datePart))
        {
            return false;
        }

        text = string.IsNullOrWhiteSpace(timePart) || IsMissingExpiry(timePart)
            ? datePart.Trim()
            : ReportsDateTimeDisplayHelper.MergeDateAndTimeParts(datePart.Trim(), timePart.Trim(), anchor);
        return true;
    }

    private static bool TryExtractFromElements(JsonElement elements, DateTime anchor, out string text)
    {
        text = "无";
        var bestScore = 0;
        string? bestText = null;
        var bestOrder = int.MinValue;

        foreach (var el in elements.EnumerateArray())
        {
            if (el.ValueKind != JsonValueKind.Object)
            {
                continue;
            }

            var score = ScoreExpiryDateElement(el);
            if (score <= 0)
            {
                continue;
            }

            var display = GetElementConfigDisplayText(el, anchor);
            if (string.IsNullOrWhiteSpace(display))
            {
                continue;
            }

            var order = TryGetIntProperty(el, "orderNum", "OrderNum") ?? 0;
            if (score > bestScore || (score == bestScore && order > bestOrder))
            {
                bestScore = score;
                bestOrder = order;
                bestText = display.Trim();
            }
        }

        if (string.IsNullOrWhiteSpace(bestText))
        {
            return false;
        }

        text = bestText;
        return true;
    }

    private static int ScoreExpiryDateElement(JsonElement el) => ScoreExpiryElement(el, ExpiryNamePattern);

    private static int ScoreExpiryTimeElement(JsonElement el) => ScoreExpiryElement(el, ExpiryTimeNamePattern);

    private static int ScoreExpiryElement(JsonElement el, Regex namePattern)
    {
        var nameHint = $"{GetStringProperty(el, "elementName", "ElementName")} {GetStringProperty(el, "inputKey", "InputKey")}"
            .Trim();
        if (string.IsNullOrWhiteSpace(nameHint))
        {
            nameHint = GetStringProperty(el, "id", "Id");
        }

        if (!string.IsNullOrWhiteSpace(nameHint) && ExcludeNamePattern.IsMatch(nameHint))
        {
            return -1;
        }

        var typeAdd = GetStringProperty(el, "typeAdd", "TypeAdd")
            .Trim()
            .ToLowerInvariant()
            .Replace("  ", " ", StringComparison.Ordinal);

        if (ExpiryNamePattern.IsMatch(nameHint) && !IsWeekdayBarName(nameHint))
        {
            return 100;
        }

        if (typeAdd.Contains("duration date", StringComparison.Ordinal) && !IsWeekdayBarName(nameHint))
        {
            return 90;
        }

        if (TryGetProperty(el, "config", out var cfg) || TryGetProperty(el, "Config", out cfg))
        {
            var native = GetStringProperty(cfg, "nativeSourceType", "NativeSourceType")
                .Trim()
                .ToUpperInvariant();
            if (native == "DATE" && ExpiryNamePattern.IsMatch(nameHint) && !IsWeekdayBarName(nameHint))
            {
                return 85;
            }
        }

        var type = GetStringProperty(el, "type", "Type").Trim().ToUpperInvariant();
        if (type is "DATE" or "DURATION" or "TIME")
        {
            if (ExpiryNamePattern.IsMatch(nameHint) && !IsWeekdayBarName(nameHint))
            {
                return 75;
            }
        }

        return 0;
    }

    private static bool IsWeekdayBarName(string nameHint) =>
        Regex.IsMatch(
            nameHint,
            @"durationdate2|duration_date_2|durationdate_2|duration\s*date\s*2",
            RegexOptions.IgnoreCase | RegexOptions.CultureInvariant);

    private static string? GetElementConfigDisplayText(JsonElement el, DateTime anchor)
    {
        if (!TryGetProperty(el, "config", out var cfg) && !TryGetProperty(el, "Config", out cfg))
        {
            return null;
        }

        foreach (var key in new[]
                 {
                     "__previewFormatted", "__PreviewFormatted", "format", "Format", "text", "Text"
                 })
        {
            if (!cfg.TryGetProperty(key, out var v) || v.ValueKind != JsonValueKind.String)
            {
                continue;
            }

            var s = v.GetString()?.Trim();
            if (string.IsNullOrWhiteSpace(s))
            {
                continue;
            }

            if (TryResolveDisplayText(s, anchor, out var resolved))
            {
                return resolved;
            }
        }

        return null;
    }

    private static bool TryResolveDisplayText(string raw, DateTime anchor, out string text)
    {
        text = raw.Trim();
        if (TryParseOffsetPayload(text, out var amount, out var unit))
        {
            text = ReportsDateTimeDisplayHelper.FormatExpiryDateTime(
                ApplyOffset(anchor, amount, unit));
            return true;
        }

        return !string.IsNullOrWhiteSpace(text);
    }

    private static bool TryFormatJsonValueAsExpiryText(JsonElement v, DateTime anchor, out string text)
    {
        text = "无";
        if (v.ValueKind == JsonValueKind.String)
        {
            var s = v.GetString()?.Trim();
            if (string.IsNullOrWhiteSpace(s))
            {
                return false;
            }

            if (TryResolveDisplayText(s, anchor, out text))
            {
                return true;
            }

            text = s;
            return true;
        }

        if (v.ValueKind == JsonValueKind.Number && v.TryGetInt64(out var unix))
        {
            text = ReportsDateTimeDisplayHelper.FormatExpiryDateTime(
                DateTimeOffset.FromUnixTimeSeconds(unix).LocalDateTime);
            return true;
        }

        if (v.ValueKind is JsonValueKind.True or JsonValueKind.False or JsonValueKind.Number)
        {
            text = v.ToString();
            return true;
        }

        return false;
    }

    private static bool TryParseOffsetPayload(string? raw, out int amount, out string unit)
    {
        amount = 0;
        unit = "Days";
        if (string.IsNullOrWhiteSpace(raw))
        {
            return false;
        }

        var t = raw.Trim();
        if (!t.StartsWith("{"))
        {
            if (Regex.IsMatch(t, @"^\d+$"))
            {
                amount = int.Parse(t, CultureInfo.InvariantCulture);
                return true;
            }

            return false;
        }

        try
        {
            using var doc = JsonDocument.Parse(t);
            if (doc.RootElement.ValueKind != JsonValueKind.Object)
            {
                return false;
            }

            var root = doc.RootElement;
            if (!TryGetProperty(root, "unit", out var unitEl))
            {
                return false;
            }

            if (!TryGetProperty(root, "value", out var valueEl))
            {
                return false;
            }

            unit = unitEl.ValueKind == JsonValueKind.String
                ? (unitEl.GetString() ?? "Days").Trim()
                : "Days";
            var valStr = valueEl.ValueKind == JsonValueKind.Number
                ? valueEl.GetRawText()
                : valueEl.GetString();
            if (!int.TryParse(valStr, NumberStyles.Integer, CultureInfo.InvariantCulture, out amount))
            {
                if (double.TryParse(valStr, NumberStyles.Float, CultureInfo.InvariantCulture, out var d))
                {
                    amount = (int)Math.Round(d);
                }
                else
                {
                    return false;
                }
            }

            return true;
        }
        catch
        {
            return false;
        }
    }

    private static DateTime ApplyOffset(DateTime baseTime, int amount, string unit)
    {
        var u = unit.Trim().ToLowerInvariant();
        return u switch
        {
            "hour" or "hours" => baseTime.AddHours(amount),
            "minute" or "minutes" => baseTime.AddMinutes(amount),
            _ => baseTime.AddDays(amount)
        };
    }

    private static bool TryGetProperty(JsonElement obj, string name, out JsonElement value)
    {
        if (obj.TryGetProperty(name, out value))
        {
            return true;
        }

        if (name.Length > 0)
        {
            var pascal = char.ToUpperInvariant(name[0]) + name[1..];
            if (obj.TryGetProperty(pascal, out value))
            {
                return true;
            }
        }

        value = default;
        return false;
    }

    private static string GetStringProperty(JsonElement obj, params string[] names)
    {
        foreach (var name in names)
        {
            if (TryGetProperty(obj, name, out var v) && v.ValueKind == JsonValueKind.String)
            {
                return v.GetString() ?? string.Empty;
            }
        }

        return string.Empty;
    }

    private static int? GetNumberProperty(JsonElement obj, params string[] names)
    {
        foreach (var name in names)
        {
            if (!TryGetProperty(obj, name, out var v))
            {
                continue;
            }

            if (v.ValueKind == JsonValueKind.Number && v.TryGetInt32(out var n))
            {
                return n;
            }

            if (v.ValueKind == JsonValueKind.String &&
                int.TryParse(v.GetString(), NumberStyles.Integer, CultureInfo.InvariantCulture, out n))
            {
                return n;
            }
        }

        return null;
    }

    private static int? TryGetIntProperty(JsonElement obj, params string[] names)
    {
        foreach (var name in names)
        {
            if (!TryGetProperty(obj, name, out var v))
            {
                continue;
            }

            if (v.ValueKind == JsonValueKind.Number && v.TryGetInt32(out var n))
            {
                return n;
            }
        }

        return null;
    }
}