namespace WebDrop.Core;

public enum ErrorCode
{
    BadRequest,
    Unauthorized,
    Forbidden,
    NotJoined,
    MembersFull,
    ModeMismatch,
    NotFound,
    Conflict,
    Gone,
    TooLarge,
    CaptchaRequired,
    CaptchaUnavailable,
    RateLimited,
    VisitorsFull,
    Sealed,
    AccountRequired,
    InvitationRequired,
    ChannelPasswordRequired,
    ChannelPasswordInvalid,
    SpaceNameRequired,
}

/// <summary>预期内的业务失败。消息只含错误码,绝不回显用户提交的内容。</summary>
public sealed class WebDropException : Exception
{
    public ErrorCode Code { get; }

    /// <summary>仅在 410 日志续传失败时有值,见 api.md。</summary>
    public long? OldestSeq { get; }

    public WebDropException(ErrorCode code, long? oldestSeq = null) : base(code.ToWire())
    {
        Code = code;
        OldestSeq = oldestSeq;
    }
}

public static class ErrorCodes
{
    public static string ToWire(this ErrorCode code) => code switch
    {
        ErrorCode.BadRequest => "bad_request",
        ErrorCode.Unauthorized => "unauthorized",
        ErrorCode.Forbidden => "forbidden",
        ErrorCode.NotJoined => "not_joined",
        ErrorCode.MembersFull => "members_full",
        ErrorCode.ModeMismatch => "mode_mismatch",
        ErrorCode.NotFound => "not_found",
        ErrorCode.Conflict => "conflict",
        ErrorCode.Gone => "gone",
        ErrorCode.TooLarge => "too_large",
        ErrorCode.CaptchaRequired => "captcha_required",
        ErrorCode.CaptchaUnavailable => "captcha_unavailable",
        ErrorCode.RateLimited => "rate_limited",
        ErrorCode.VisitorsFull => "visitors_full",
        ErrorCode.Sealed => "sealed",
        ErrorCode.AccountRequired => "account_required",
        ErrorCode.InvitationRequired => "invitation_required",
        ErrorCode.ChannelPasswordRequired => "channel_password_required",
        ErrorCode.ChannelPasswordInvalid => "channel_password_invalid",
        ErrorCode.SpaceNameRequired => "space_name_required",
        _ => "bad_request",
    };

    public static int ToStatus(this ErrorCode code) => code switch
    {
        ErrorCode.BadRequest => 400,
        ErrorCode.Unauthorized => 401,
        ErrorCode.Forbidden or ErrorCode.NotJoined or ErrorCode.MembersFull or ErrorCode.ModeMismatch => 403,
        ErrorCode.NotFound => 404,
        ErrorCode.Conflict => 409,
        ErrorCode.Sealed => 409,
        ErrorCode.SpaceNameRequired => 400,
        ErrorCode.Gone => 410,
        ErrorCode.TooLarge => 413,
        ErrorCode.CaptchaRequired => 428,
        ErrorCode.CaptchaUnavailable => 503,
        ErrorCode.RateLimited => 429,
        ErrorCode.VisitorsFull => 403,
        ErrorCode.AccountRequired => 401,
        ErrorCode.InvitationRequired or ErrorCode.ChannelPasswordRequired or ErrorCode.ChannelPasswordInvalid => 403,
        _ => 400,
    };
}