using System;
using System.Text.RegularExpressions;

namespace SharpChat.SockChat {
    public static class SockChatUtility {
        private static readonly Regex ChannelName = new(@"[^A-Za-z0-9\-_]", RegexOptions.CultureInvariant | RegexOptions.Compiled);

        public static string SanitiseMessageBody(string? body) {
            if(string.IsNullOrEmpty(body))
                return string.Empty;

            return body.Replace("<", "&lt;").Replace(">", "&gt;").Replace("\n", " <br/> ").Replace("\t", "    ");
        }

        public static string SanitiseChannelName(string name) {
            return ChannelName.Replace(name.Replace(" ", "_"), "-");
        }

        public static bool CheckChannelName(string name) {
            return name.Length < 1 || ChannelName.IsMatch(name);
        }

        public static string GetUserName(UserInfo info) {
            return string.IsNullOrWhiteSpace(info.NickName) ? info.UserName : $"~{info.NickName}";
        }

        public static string GetUserNameWithStatus(UserInfo info) {
            string name = GetUserName(info);

            if(info.Status == UserStatus.Away)
                name = string.Format(
                    "&lt;{0}&gt;_{1}",
                    info.StatusText[..Math.Min(info.StatusText.Length, 5)].ToUpperInvariant(),
                    name
                );

            return name;
        }

        public static (string, UsersContext.NameTarget) ExplodeUserName(string name) {
            UsersContext.NameTarget target = UsersContext.NameTarget.UserName;

            if(name.StartsWith("<")) {
                int gt = name.IndexOf(">_");
                if(gt > 0) {
                    gt += 2;
                    name = name[gt..];
                }
            } else if(name.StartsWith("&lt;")) {
                int gt = name.IndexOf("&gt;_");
                if(gt > 0) {
                    gt += 5;
                    name = name[gt..];
                }
            }

            if(name.StartsWith("~")) {
                target = UsersContext.NameTarget.NickName;
                name = name[1..];
            }

            return (name, target);
        }
    }
}