namespace Aeshnidae.Inspect;

/// <summary>
/// /inspect - the numbers the appraisal window does not show for a creature: its
/// effective attack skill and its three defenses, as the combat formulas will use
/// them right now (attributes, tier scaling, buffs and debuffs all applied), with
/// the unbuffed base beside any that differ.
/// </summary>
public static class Commands
{
    [CommandHandler("inspect", AccessLevel.Player, CommandHandlerFlag.RequiresWorld, -1,
        "The effective attack skill and melee, missile and magic defense of the creature you have selected.",
        "/inspect             the creature you have selected\n" +
        "/inspect <name>      the nearest creature of that name instead")]
    public static void HandleInspect(Session session, params string[] parameters)
    {
        var player = session.Player;

        if (player is null)
            return;

        try
        {
            var target = parameters.Length > 0
                ? Nearest(player, string.Join(" ", parameters))
                : Selected(player);

            if (target is null)
            {
                Reply(session, parameters.Length > 0
                    ? $"No creature called '{string.Join(" ", parameters)}' within {Mod.Settings.NameSearchRange:0} metres."
                    : "Select a creature first, or give a name: /inspect <name>.");
                return;
            }

            if (target is Player && !Mod.Settings.AllowInspectingPlayers && session.AccessLevel < AccessLevel.Admin)
            {
                Reply(session, "Players keep their numbers to themselves.");
                return;
            }

            Reply(session, Describe(target));
        }
        catch (Exception ex)
        {
            ModManager.Log($"[{Mod.Name}] /inspect failed for {player.Name}: {ex}", ModManager.LogLevel.Error);
            Reply(session, "Could not read that creature.");
        }
    }

    [CommandHandler("inspect-reload", AccessLevel.Admin, CommandHandlerFlag.None, 0,
        "Restart the Aeshnidae.Inspect mod, re-reading Settings.json.",
        "/inspect-reload")]
    public static void HandleReload(Session session, params string[] parameters)
    {
        var container = Mod.Container;

        if (container is null)
        {
            Reply(session, $"{Mod.Name} is not loaded.");
            return;
        }

        container.Restart();
        Reply(session, $"{Mod.Name} restarted.");
    }

    /// <summary>
    /// The client sends an appraisal for whatever the player selects, so the last
    /// appraisal REQUEST is the selection. Not CurrentAppraisalTarget: ACE only sets
    /// that when the Assess Creature roll against the monster's Deception succeeds,
    /// and a failed assess would leave /inspect claiming nothing was selected.
    /// Looked up through the player's landblock so an instanced copy answers for its
    /// own creatures.
    /// </summary>
    private static Creature? Selected(Player player)
    {
        var guid = player.RequestedAppraisalTarget ?? player.CurrentAppraisalTarget;

        if (guid is null)
            return null;

        return player.FindObject(guid.Value, Player.SearchLocations.Landblock | Player.SearchLocations.ObjectsKnownByMe) as Creature;
    }

    private static Creature? Nearest(Player player, string name)
    {
        var range = Mod.Settings.NameSearchRange;

        return player.GetKnownObjects()
            .OfType<Creature>()
            .Where(c => c != player && c.Name.Equals(name, StringComparison.OrdinalIgnoreCase))
            .Select(c => (creature: c, distance: player.Location.DistanceTo(c.Location)))
            .Where(t => t.distance <= range)
            .OrderBy(t => t.distance)
            .Select(t => t.creature)
            .FirstOrDefault();
    }

    private static string Describe(Creature c)
    {
        var sb = new StringBuilder();

        sb.AppendLine($"{c.Name} - level {c.Level ?? 0}, {c.Health.Current:N0}/{c.Health.MaxValue:N0} health");

        // The skill the next swing will roll. A caster's bolts roll War Magic instead,
        // so that is shown too whenever the creature has it.
        var attack = c.GetCurrentAttackSkill();
        sb.AppendLine($"  attack          : {attack.ToSentence()} {Number(c, attack)}");

        var war = c.GetCreatureSkill(Skill.WarMagic);
        if (war.AdvancementClass >= SkillAdvancementClass.Trained && attack != Skill.WarMagic)
            sb.AppendLine($"  war magic       : {Number(c, Skill.WarMagic)}");

        sb.AppendLine($"  melee defense   : {Number(c, Skill.MeleeDefense)}");
        sb.AppendLine($"  missile defense : {Number(c, Skill.MissileDefense)}");
        sb.AppendLine($"  magic defense   : {Number(c, Skill.MagicDefense)}");

        var ratings = new List<string>();
        Rating(ratings, "damage", c.GetDamageRating());
        Rating(ratings, "damage resist", c.GetDamageResistRating());
        Rating(ratings, "crit", c.GetCritRating());
        Rating(ratings, "crit damage", c.GetCritDamageRating());

        if (ratings.Count > 0)
            sb.AppendLine($"  ratings         : {string.Join(", ", ratings)}");

        return sb.ToString().TrimEnd();
    }

    /// <summary>"150", or "135 (base 150)" when spells have moved it.</summary>
    private static string Number(Creature c, Skill skill)
    {
        var cs = c.GetCreatureSkill(skill);
        var current = cs.Current;
        var baseValue = cs.Base;

        return current == baseValue ? $"{current}" : $"{current} (base {baseValue})";
    }

    private static void Rating(List<string> into, string name, int value)
    {
        if (value != 0)
            into.Add($"{name} {(value > 0 ? "+" : "")}{value}");
    }

    /// <summary>
    /// The client renders an embedded newline as a music note, so a multi-line
    /// message has to go out as one SendMessage per line.
    /// </summary>
    private static void Reply(Session? session, string message)
    {
        if (session?.Player is null)
        {
            ModManager.Log(message);
            return;
        }

        foreach (var line in (message ?? "").Split('\n'))
        {
            var text = line.TrimEnd('\r');

            if (!string.IsNullOrWhiteSpace(text))
                session.Player.SendMessage(text);
        }
    }
}