using System;
using System.Collections.Generic;
using System.Reflection;

namespace Discord.Interactions.Builders
{
    /// <summary>
    ///     Represents a builder for creating <see cref="ModuleInfo"/>.
    /// </summary>
    public class ModuleBuilder
    {
        private readonly List<Attribute> _attributes;
        private readonly List<PreconditionAttribute> _preconditions;
        private readonly List<ModuleBuilder> _subModules;
        private readonly List<SlashCommandBuilder> _slashCommands;
        private readonly List<ContextCommandBuilder> _contextCommands;
        private readonly List<ComponentCommandBuilder> _componentCommands;
        private readonly List<AutocompleteCommandBuilder> _autocompleteCommands;
        private readonly List<ModalCommandBuilder> _modalCommands;

        /// <summary>
        ///     Gets the underlying Interaction Service.
        /// </summary>
        public InteractionService InteractionService { get; }

        /// <summary>
        ///     Gets the parent module if this module is a sub-module.
        /// </summary>
        public ModuleBuilder Parent { get; }

        /// <summary>
        ///     Gets the name of this module.
        /// </summary>
        public string Name { get; internal set; }

        /// <summary>
        ///     Gets and sets the group name of this module.
        /// </summary>
        public string SlashGroupName { get; set; }

        /// <summary>
        ///     Gets whether this has a <see cref="GroupAttribute"/>.
        /// </summary>
        public bool IsSlashGroup => !string.IsNullOrEmpty(SlashGroupName);

        /// <summary>
        ///     Gets and sets the description of this module.
        /// </summary>
        public string Description { get; set; }

        /// <summary>
        ///     Gets and sets the default permission of this module.
        /// </summary>
        [Obsolete($"To be deprecated soon, use {nameof(IsEnabledInDm)} and {nameof(DefaultMemberPermissions)} instead.")]
        public bool DefaultPermission { get; set; } = true;

        /// <summary>
        ///     Gets whether this command can be used in DMs.
        /// </summary>
        public bool IsEnabledInDm { get; set; } = true;

        /// <summary>
        ///     Gets the default permissions needed for executing this command.
        /// </summary>
        public GuildPermission? DefaultMemberPermissions { get; set; } = null;

        /// <summary>
        ///     Gets and sets whether this has a <see cref="DontAutoRegisterAttribute"/>.
        /// </summary>
        public bool DontAutoRegister { get; set; } = false;

        /// <summary>
        ///     Gets a collection of the attributes of this module.
        /// </summary>
        public IReadOnlyList<Attribute> Attributes => _attributes;

        /// <summary>
        ///     Gets a collection of the preconditions of this module.
        /// </summary>
        public IReadOnlyCollection<PreconditionAttribute> Preconditions => _preconditions;

        /// <summary>
        ///     Gets a collection of the sub-modules of this module.
        /// </summary>
        public IReadOnlyList<ModuleBuilder> SubModules => _subModules;

        /// <summary>
        ///     Gets a collection of the Slash Commands of this module.
        /// </summary>
        public IReadOnlyList<SlashCommandBuilder> SlashCommands => _slashCommands;

        /// <summary>
        ///     Gets a collection of the Context Commands of this module.
        /// </summary>
        public IReadOnlyList<ContextCommandBuilder> ContextCommands => _contextCommands;

        /// <summary>
        ///     Gets a collection of the Component Commands of this module.
        /// </summary>
        public IReadOnlyList<ComponentCommandBuilder> ComponentCommands => _componentCommands;

        /// <summary>
        ///     Gets a collection of the Autocomplete Commands of this module.
        /// </summary>
        public IReadOnlyList<AutocompleteCommandBuilder> AutocompleteCommands => _autocompleteCommands;

        /// <summary>
        ///     Gets a collection of the Modal Commands of this module.
        /// </summary>
        public IReadOnlyList<ModalCommandBuilder> ModalCommands => _modalCommands;

        internal TypeInfo TypeInfo { get; set; }

        internal ModuleBuilder (InteractionService interactionService, ModuleBuilder parent = null)
        {
            InteractionService = interactionService;
            Parent = parent;

            _attributes = new List<Attribute>();
            _subModules = new List<ModuleBuilder>();
            _slashCommands = new List<SlashCommandBuilder>();
            _contextCommands = new List<ContextCommandBuilder>();
            _componentCommands = new List<ComponentCommandBuilder>();
            _autocompleteCommands = new List<AutocompleteCommandBuilder>();
            _modalCommands = new List<ModalCommandBuilder> ();
            _preconditions = new List<PreconditionAttribute>();
        }

        /// <summary>
        ///     Initializes a new <see cref="ModuleBuilder"/>.
        /// </summary>
        /// <param name="interactionService">The underlying Interaction Service.</param>
        /// <param name="name">Name of this module.</param>
        /// <param name="parent">Parent module of this sub-module.</param>
        public ModuleBuilder (InteractionService interactionService, string name, ModuleBuilder parent = null) : this(interactionService, parent)
        {
            Name = name;
        }

        /// <summary>
        ///     Sets <see cref="SlashGroupName"/>.
        /// </summary>
        /// <param name="name">New value of the <see cref="SlashGroupName"/>.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder WithGroupName (string name)
        {
            SlashGroupName = name;
            return this;
        }

        /// <summary>
        ///     Sets <see cref="Description"/>.
        /// </summary>
        /// <param name="description">New value of the <see cref="Description"/>.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder WithDescription (string description)
        {
            Description = description;
            return this;
        }

        /// <summary>
        ///     Sets <see cref="DefaultPermission"/>.
        /// </summary>
        /// <param name="permission">New value of the <see cref="DefaultPermission"/>.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        [Obsolete($"To be deprecated soon, use {nameof(SetEnabledInDm)} and {nameof(WithDefaultMemberPermissions)} instead.")]
        public ModuleBuilder WithDefaultPermission (bool permission)
        {
            DefaultPermission = permission;
            return this;
        }

        /// <summary>
        ///     Sets <see cref="IsEnabledInDm"/>.
        /// </summary>
        /// <param name="isEnabled">New value of the <see cref="IsEnabledInDm"/>.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder SetEnabledInDm(bool isEnabled)
        {
            IsEnabledInDm = isEnabled;
            return this;
        }

        /// <summary>
        ///     Sets <see cref="DefaultMemberPermissions"/>.
        /// </summary>
        /// <param name="permissions">New value of the <see cref="DefaultMemberPermissions"/>.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder WithDefaultMemberPermissions(GuildPermission permissions)
        {
            DefaultMemberPermissions = permissions;
            return this;
        }

        /// <summary>
        ///     Adds attributes to <see cref="Attributes"/>.
        /// </summary>
        /// <param name="attributes">New attributes to be added to <see cref="Attributes"/>.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder AddAttributes (params Attribute[] attributes)
        {
            _attributes.AddRange(attributes);
            return this;
        }

        /// <summary>
        ///     Adds preconditions to <see cref="Preconditions"/>.
        /// </summary>
        /// <param name="preconditions">New preconditions to be added to <see cref="Preconditions"/>.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder AddPreconditions (params PreconditionAttribute[] preconditions)
        {
            _preconditions.AddRange(preconditions);
            return this;
        }

        /// <summary>
        ///     Adds slash command builder to <see cref="SlashCommands"/>.
        /// </summary>
        /// <param name="configure"><see cref="SlashCommandBuilder"/> factory.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder AddSlashCommand (Action<SlashCommandBuilder> configure)
        {
            var command = new SlashCommandBuilder(this);
            configure(command);
            _slashCommands.Add(command);
            return this;
        }

        /// <summary>
        ///     Adds slash command builder to <see cref="SlashCommands"/>.
        /// </summary>
        /// <param name="name">Name of the command.</param>
        /// <param name="callback">Command callback to be executed.</param>
        /// <param name="configure"><see cref="SlashCommandBuilder"/> factory.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder AddSlashCommand(string name, ExecuteCallback callback, Action<SlashCommandBuilder> configure)
        {
            var command = new SlashCommandBuilder(this, name, callback);
            configure(command);
            _slashCommands.Add(command);
            return this;
        }

        /// <summary>
        ///     Adds context command builder to <see cref="ContextCommands"/>.
        /// </summary>
        /// <param name="configure"><see cref="ContextCommandBuilder"/> factory.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder AddContextCommand (Action<ContextCommandBuilder> configure)
        {
            var command = new ContextCommandBuilder(this);
            configure(command);
            _contextCommands.Add(command);
            return this;
        }

        /// <summary>
        ///     Adds context command builder to <see cref="ContextCommands"/>.
        /// </summary>
        /// <param name="name">Name of the command.</param>
        /// <param name="callback">Command callback to be executed.</param>
        /// <param name="configure"><see cref="ContextCommandBuilder"/> factory.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder AddContextCommand(string name, ExecuteCallback callback, Action<ContextCommandBuilder> configure)
        {
            var command = new ContextCommandBuilder(this, name, callback);
            configure(command);
            _contextCommands.Add(command);
            return this;
        }

        /// <summary>
        ///     Adds component command builder to <see cref="ComponentCommands"/>.
        /// </summary>
        /// <param name="configure"><see cref="ComponentCommandBuilder"/> factory.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder AddComponentCommand (Action<ComponentCommandBuilder> configure)
        {
            var command = new ComponentCommandBuilder(this);
            configure(command);
            _componentCommands.Add(command);
            return this;
        }

        /// <summary>
        ///     Adds component command builder to <see cref="ComponentCommands"/>.
        /// </summary>
        /// <param name="name">Name of the command.</param>
        /// <param name="callback">Command callback to be executed.</param>
        /// <param name="configure"><see cref="ComponentCommandBuilder"/> factory.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder AddComponentCommand(string name, ExecuteCallback callback, Action<ComponentCommandBuilder> configure)
        {
            var command = new ComponentCommandBuilder(this, name, callback);
            configure(command);
            _componentCommands.Add(command);
            return this;
        }

        /// <summary>
        ///     Adds autocomplete command builder to <see cref="AutocompleteCommands"/>.
        /// </summary>
        /// <param name="configure"><see cref="AutocompleteCommands"/> factory.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder AddAutocompleteCommand(Action<AutocompleteCommandBuilder> configure)
        {
            var command = new AutocompleteCommandBuilder(this);
            configure(command);
            _autocompleteCommands.Add(command);
            return this;
        }

        /// <summary>
        ///     Adds autocomplete command builder to <see cref="AutocompleteCommands"/>.
        /// </summary>
        /// <param name="name">Name of the command.</param>
        /// <param name="callback">Command callback to be executed.</param>
        /// <param name="configure"><see cref="AutocompleteCommandBuilder"/> factory.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder AddSlashCommand(string name, ExecuteCallback callback, Action<AutocompleteCommandBuilder> configure)
        {
            var command = new AutocompleteCommandBuilder(this, name, callback);
            configure(command);
            _autocompleteCommands.Add(command);
            return this;

        }
        
        ///     Adds a modal command builder to <see cref="ModalCommands"/>.
        /// </summary>
        /// <param name="configure"><see cref="ModalCommands"/> factory.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder AddModalCommand(Action<ModalCommandBuilder> configure)
        {
            var command = new ModalCommandBuilder(this);
            configure(command);
            _modalCommands.Add(command);
            return this;
        }

        /// <summary>
        ///     Adds sub-module builder to <see cref="SubModules"/>.
        /// </summary>
        /// <param name="configure"><see cref="ModuleBuilder"/> factory.</param>
        /// <returns>
        ///     The builder instance.
        /// </returns>
        public ModuleBuilder AddModule (Action<ModuleBuilder> configure)
        {
            var subModule = new ModuleBuilder(InteractionService, this);
            configure(subModule);
            _subModules.Add(subModule);
            return this;
        }

        internal ModuleInfo Build (InteractionService interactionService, IServiceProvider services, ModuleInfo parent = null)
        {
            if (TypeInfo is not null && ModuleClassBuilder.IsValidModuleDefinition(TypeInfo))
            {
                var instance = ReflectionUtils<IInteractionModuleBase>.CreateObject(TypeInfo, interactionService, services);

                try
                {
                    instance.Construct(this, interactionService);
                    var moduleInfo = new ModuleInfo(this, interactionService, services, parent);
                    instance.OnModuleBuilding(interactionService, moduleInfo);
                    return moduleInfo;
                }
                finally
                {
                    (instance as IDisposable)?.Dispose();
                }
            }
            else
                return new(this, interactionService, services, parent);
        }
    }
}