using System.Text.RegularExpressions;

namespace OrderSupportTicket.TestServer;

/// <summary>
/// 与客户端 OrderSupportTicket.Services.TicketApiService 保持一致的参数规则。
/// </summary>
public static class ContractValidator
{
    private static readonly Regex AppIdRegex =
        new(@"^wx[0-9a-f]{16}$", RegexOptions.Compiled | RegexOptions.CultureInvariant);

    private static readonly Regex OrderIdRegex =
        new(@"^[0-9]{10,64}$", RegexOptions.Compiled | RegexOptions.CultureInvariant);

    private static readonly Regex PurchaseAccountRegex =
        new(@"^[\p{L}\p{N}_.@-]{2,120}$", RegexOptions.Compiled);

    private static readonly Regex OperationIdRegex =
        new(@"^[A-Za-z0-9_.:-]{1,128}$", RegexOptions.Compiled | RegexOptions.CultureInvariant);

    private static readonly HashSet<string> Statuses =
        new(StringComparer.OrdinalIgnoreCase)
        {
            "waiting_reply",
            "replied",
            "completed"
        };

    public static string PurchaseAccount(string? value)
    {
        var normalized = value?.Trim();
        if (string.IsNullOrWhiteSpace(normalized) || !PurchaseAccountRegex.IsMatch(normalized))
        {
            throw BadRequest(
                "purchaseAccount 必填，且只能为 2～120 位中英文、数字或 _.@-。",
                "invalid_purchase_account");
        }

        return normalized;
    }

    public static string AppId(string? value)
    {
        var normalized = value?.Trim();
        if (string.IsNullOrWhiteSpace(normalized) || !AppIdRegex.IsMatch(normalized))
        {
            throw BadRequest(
                "appId 必须为 wx 加 16 位小写十六进制字符。",
                "invalid_app_id");
        }

        return normalized;
    }

    public static string WechatOrderId(string? value)
    {
        var normalized = value?.Trim();
        if (string.IsNullOrWhiteSpace(normalized) || !OrderIdRegex.IsMatch(normalized))
        {
            throw BadRequest(
                "wechatOrderId 必须保持为 10～64 位数字字符串。",
                "invalid_wechat_order_id");
        }

        return normalized;
    }

    public static string Description(string? value)
    {
        var normalized = value?.Trim();
        if (string.IsNullOrWhiteSpace(normalized) || normalized.Length > 2000)
        {
            throw BadRequest(
                "description 必须为 1～2000 字。",
                "invalid_description");
        }

        return normalized;
    }

    public static string MessageText(string? value)
    {
        var normalized = value?.Trim();
        if (string.IsNullOrWhiteSpace(normalized) || normalized.Length > 4000)
        {
            throw BadRequest(
                "text 必须为 1～4000 字。",
                "invalid_message_text");
        }

        return normalized;
    }

    public static string? OptionalOperationId(string? value, string parameterName)
    {
        if (string.IsNullOrWhiteSpace(value))
        {
            return null;
        }

        return OperationId(value, parameterName);
    }

    public static string OperationId(string? value, string parameterName)
    {
        var normalized = value?.Trim();
        if (string.IsNullOrWhiteSpace(normalized) || !OperationIdRegex.IsMatch(normalized))
        {
            throw BadRequest(
                parameterName + " 必须为 1～128 位字母、数字或 _.:-。",
                "invalid_operation_id");
        }

        return normalized;
    }

    public static string? Status(string? value)
    {
        if (string.IsNullOrWhiteSpace(value))
        {
            return null;
        }

        var normalized = value.Trim().ToLowerInvariant();
        if (!Statuses.Contains(normalized))
        {
            throw BadRequest(
                "status 只能为 waiting_reply、replied 或 completed。",
                "invalid_status");
        }

        return normalized;
    }

    public static int Limit(int value, int fallback)
    {
        if (value == 0)
        {
            value = fallback;
        }

        if (value is < 1 or > 100)
        {
            throw BadRequest("limit 必须为 1～100。", "invalid_limit");
        }

        return value;
    }

    public static ApiException BadRequest(string message, string code) =>
        new(StatusCodes.Status400BadRequest, message, code);

    public static ApiException NotFound(string message, string code = "work_order_not_found") =>
        new(StatusCodes.Status404NotFound, message, code);
}