namespace GroupVerify;

// The plugin's settings, from gv_settings. Immutable: a reload swaps in a new one.
internal sealed record Settings(
    bool Enabled,
    ulong GroupId64,
    int MinForcedRefreshSeconds,
    int DbReloadSeconds,
    TimeZoneInfo TimeZone,
    string VerifyMinRank,
    string[] VerifyExtraRanks,
    string ClanTag)
{
    // Written to gv_settings when missing. The rank defaults are our real SimpleAdmin groups (see
    // the fork's Helper.StaffRanks and the web panel's site config). Only the names are set here:
    // "Admin or higher" is decided by immunity read from sa_groups.
    public static readonly (string Name, string Value)[] Defaults =
    [
        ("enabled", "1"),                        // 0 turns verification off (css_gv_enable/css_gv_disable)
        ("group_id64", "0"),                     // the Steam group's 64-bit ID (103582791...); 0 turns verification off (css_gv_group)
        ("min_forced_refresh_seconds", "60"),    // a player is rechecked with Steam (css_verify, rejoining) at most this often
        ("db_reload_seconds", "60"),             // how often gv_verified and gv_settings are reread
        ("timezone", "UTC"),                     // must match CS2-SimpleAdmin's Timezone
        ("verify_min_rank", "#rank/admin"),      // css_verify: this group's immunity or higher
        ("verify_extra_ranks", "#rank/guardian"), // css_verify: these groups too, comma-separated
        ("clan_tag", "")                          // scoreboard tag for verified players without a rank (css_gv_clantag)
    ];

    public static readonly Settings Default = Parse(new Dictionary<string, string>(), _ => { });

    public static Settings Parse(IReadOnlyDictionary<string, string> values, Action<string> warn)
    {
        string Get(string name) =>
            values.TryGetValue(name, out var value) ? value.Trim() : Defaults.First(d => d.Name == name).Value;

        int GetInt(string name, int min)
        {
            if (int.TryParse(Get(name), out var value) && value >= min)
                return value;
            var fallback = int.Parse(Defaults.First(d => d.Name == name).Value);
            warn($"gv_settings {name} must be a number of at least {min}; using {fallback}");
            return fallback;
        }

        ulong groupId = 0;
        var groupText = Get("group_id64");
        if (groupText.Length > 0 && !ulong.TryParse(groupText, out groupId))
            warn($"gv_settings group_id64 \"{groupText}\" isn't a 64-bit group ID; verification is off");

        var timeZone = TimeZoneInfo.Utc;
        var zoneName = Get("timezone");
        try
        {
            timeZone = TimeZoneInfo.FindSystemTimeZoneById(zoneName);
        }
        catch (Exception ex) when (ex is TimeZoneNotFoundException or InvalidTimeZoneException)
        {
            warn($"gv_settings timezone \"{zoneName}\" isn't a known time zone; using UTC");
        }

        return new Settings(
            Get("enabled") != "0",
            groupId,
            GetInt("min_forced_refresh_seconds", 0),
            GetInt("db_reload_seconds", 10),
            timeZone,
            Get("verify_min_rank"),
            Get("verify_extra_ranks").Split(',', StringSplitOptions.TrimEntries | StringSplitOptions.RemoveEmptyEntries),
            ParseClanTag(Get("clan_tag"), warn));
    }

    // Steam's own group tags are at most 12 characters. Quotes and control characters are refused,
    // since the tag travels in console commands.
    public const int ClanTagMaxLength = 12;

    public static bool ValidClanTag(string tag) =>
        tag.Length <= ClanTagMaxLength && !tag.Any(c => char.IsControl(c) || c == '"' || c == ';');

    private static string ParseClanTag(string tag, Action<string> warn)
    {
        if (ValidClanTag(tag))
            return tag;
        warn($"gv_settings clan_tag \"{tag}\" must be at most {ClanTagMaxLength} characters, without quotes, ; or control characters; ignoring it");
        return "";
    }

    // The tag other plugins see: none while verification is off.
    public string EffectiveClanTag => Active ? ClanTag : "";

    // Verification only runs when enabled with a group set; otherwise nobody is verified.
    public bool Active => Enabled && GroupId64 != 0;

    // Now as a wall-clock time in the database's time zone, to the second (MySQL rounds fractions).
    public DateTime Now()
    {
        var now = TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, TimeZone);
        return DateTime.SpecifyKind(now.AddTicks(-(now.Ticks % TimeSpan.TicksPerSecond)), DateTimeKind.Unspecified);
    }
}