using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Linq;
using System.Threading.Tasks;
using Model = Discord.API.ApplicationCommand;

namespace Discord.Rest
{
    /// <summary>
    ///     Represents a Rest-based implementation of the <see cref="IApplicationCommand"/>.
    /// </summary>
    public abstract class RestApplicationCommand : RestEntity<ulong>, IApplicationCommand
    {
        /// <inheritdoc/>
        public ulong ApplicationId { get; private set; }

        /// <inheritdoc/>
        public ApplicationCommandType Type { get; private set; }

        /// <inheritdoc/>
        public string Name { get; private set; }

        /// <inheritdoc/>
        public string Description { get; private set; }

        /// <inheritdoc/>
        public bool IsDefaultPermission { get; private set; }

        /// <inheritdoc/>
        public bool IsEnabledInDm { get; private set; }

        /// <inheritdoc/>
        public GuildPermissions DefaultMemberPermissions { get; private set; }

        /// <summary>
        ///     Gets a collection of options for this command.
        /// </summary>
        public IReadOnlyCollection<RestApplicationCommandOption> Options { get; private set; }

        /// <inheritdoc/>
        public DateTimeOffset CreatedAt
            => SnowflakeUtils.FromSnowflake(Id);

        internal RestApplicationCommand(BaseDiscordClient client, ulong id)
            : base(client, id) { }

        internal static RestApplicationCommand Create(BaseDiscordClient client, Model model, ulong? guildId)
        {
            return guildId.HasValue
                ? RestGuildCommand.Create(client, model, guildId.Value)
                : RestGlobalCommand.Create(client, model);
        }

        internal virtual void Update(Model model)
        {
            Type = model.Type;
            ApplicationId = model.ApplicationId;
            Name = model.Name;
            Description = model.Description;
            IsDefaultPermission = model.DefaultPermissions.GetValueOrDefault(true);

            Options = model.Options.IsSpecified
                ? model.Options.Value.Select(RestApplicationCommandOption.Create).ToImmutableArray()
                : ImmutableArray.Create<RestApplicationCommandOption>();

            IsEnabledInDm = model.DmPermission.GetValueOrDefault(true).GetValueOrDefault(true);
            DefaultMemberPermissions = new GuildPermissions((ulong)model.DefaultMemberPermission.GetValueOrDefault(0).GetValueOrDefault(0));
        }

        /// <inheritdoc/>
        public abstract Task DeleteAsync(RequestOptions options = null);

        /// <inheritdoc />
        public Task ModifyAsync(Action<ApplicationCommandProperties> func, RequestOptions options = null)
        {
            return ModifyAsync<ApplicationCommandProperties>(func, options);
        }

        /// <inheritdoc/>
        public abstract Task ModifyAsync<TArg>(Action<TArg> func, RequestOptions options = null)
            where TArg : ApplicationCommandProperties;

        IReadOnlyCollection<IApplicationCommandOption> IApplicationCommand.Options => Options;
    }
}