using System.Text;

using Humanizer;

using PluralKit.Core;

namespace PluralKit.Bot;

public class SystemList
{
    public async Task MemberList(Context ctx, PKSystem target, string? query, IHasListOptions flags)
    {
        ctx.CheckSystem(target);

        if (target == null) throw Errors.NoSystemError(ctx.DefaultPrefix);
        ctx.CheckSystemPrivacy(target.Id, target.MemberListPrivacy);

        var opts = flags.GetListOptions(ctx, target.Id);
        opts.Search = query;

        // explanation of privacy lookup here:
        // - ParseListOptions checks list access privacy and sets the privacy filter (which members show up in list)
        // - RenderMemberList checks the indivual privacy for each member (NameFor, etc)
        // the own system is always allowed to look up their list
        await ctx.RenderMemberList(
            ctx.LookupContextFor(target.Id),
            target.Id,
            await GetEmbedTitle(target, opts, ctx),
            target.Color,
            opts
        );
    }

    private async Task<string> GetEmbedTitle(PKSystem target, ListOptions opts, Context ctx)
    {
        var title = new StringBuilder("Members of ");

        var systemGuildSettings = ctx.Guild != null ? await ctx.Repository.GetSystemGuild(ctx.Guild.Id, target.Id) : null;
        if (systemGuildSettings != null && systemGuildSettings.DisplayName != null)
            title.Append($"{systemGuildSettings.DisplayName}  (`{target.DisplayHid(ctx.Config)}`)");
        else if (target.NameFor(ctx) != null)
            title.Append($"{target.NameFor(ctx)} (`{target.DisplayHid(ctx.Config)}`)");
        else
            title.Append($"`{target.DisplayHid(ctx.Config)}`");

        if (opts.Search != null)
            title.Append($" matching **{opts.Search.Truncate(100)}**");

        return title.ToString();
    }
}