using System;
using System.Collections.Generic;
using Continentis.MainGame.Character;
using Cysharp.Threading.Tasks;

namespace SLSUtilities.General
{
    /// <summary>
    /// 命令静态工厂。
    /// Mod 制作者通过此类创建常用命令，无需直接实例化具体命令类。
    /// </summary>
    public static class Cmd
    {
        // ── 基础工厂 ─────────────────────────────────────────────────────

        /// <summary>创建一条等待指定秒数后完成的命令。</summary>
        public static CommandBase Wait(float seconds)
        {
            return new WaitCommand(seconds);
        }

        /// <summary>创建一条执行同步 Action 的命令。</summary>
        public static CommandBase Do(Action action)
        {
            return new ActionCommand(action);
        }

        /// <summary>创建一条执行异步 UniTask 的命令。</summary>
        public static CommandBase Do(Func<UniTask> asyncAction)
        {
            return new AsyncActionCommand(asyncAction);
        }

        /// <summary>创建一条延迟指定秒数后执行同步 Action 的命令。</summary>
        public static CommandBase After(float seconds, Action action)
        {
            return new ActionCommand(action).SetDelay(seconds);
        }

        /// <summary>
        /// 创建一条"等待外部信号"命令。
        /// 调用返回的 <paramref name="signal"/> Action 时，命令立即完成，队列继续执行。
        /// 典型用法：等待玩家点击按钮确认。
        /// </summary>
        /// <param name="signal">外部调用此委托以释放命令。</param>
        public static CommandBase WaitForSignal(out Action signal)
        {
            var tcs = new UniTaskCompletionSource();
            signal = () => tcs.TrySetResult();
            return new WaitForSignalCommand(tcs);
        }

        // ── 组合工厂 ─────────────────────────────────────────────────────

        /// <summary>创建一个顺序执行的命令组。</summary>
        public static CommandGroup Sequential(params CommandBase[] cmds)
        {
            return new CommandGroup(ExecutionMode.Sequential, cmds);
        }

        /// <summary>创建一个并行执行的命令组。</summary>
        public static CommandGroup Parallel(params CommandBase[] cmds)
        {
            return new CommandGroup(ExecutionMode.Parallel, cmds);
        }

        // ── Target 遍历工厂 ───────────────────────────────────────────────

        /// <summary>
        /// 对 <paramref name="targets"/> 列表中的每个目标调用 <paramref name="factory"/>，
        /// 将结果按顺序组合为一个 Sequential <see cref="CommandGroup"/>。
        /// </summary>
        public static CommandGroup ForEachTarget(
            List<CharacterBase> targets,
            Func<CharacterBase, CommandBase> factory)
        {
            var group = new CommandGroup(ExecutionMode.Sequential);
            foreach (CharacterBase target in targets)
            {
                CharacterBase captured = target;
                group.AddCommand(factory(captured));
            }
            return group;
        }

        /// <summary>
        /// 对 <paramref name="targets"/> 列表中的每个目标调用 <paramref name="factory"/>，
        /// 将结果按顺序组合为一个 Sequential <see cref="CommandGroup"/>。
        /// </summary>
        public static CommandGroup ForEachTarget(
            List<CharacterBase> targets,
            Func<CharacterBase, CommandGroup> factory)
        {
            var group = new CommandGroup(ExecutionMode.Sequential);
            foreach (CharacterBase target in targets)
            {
                CharacterBase captured = target;
                group.AddCommand(factory(captured));
            }
            return group;
        }

        // ── 内部实现类 ────────────────────────────────────────────────────

        private sealed class WaitCommand : CommandBase
        {
            private readonly float seconds;

            public WaitCommand(float seconds)
            {
                this.seconds = seconds;
            }

            protected override async UniTask ExecuteAsync(CommandContext outerContext)
            {
                await UniTask.Delay(TimeSpan.FromSeconds(seconds));
            }
        }

        private sealed class ActionCommand : CommandBase
        {
            private readonly Action action;

            public ActionCommand(Action action)
            {
                this.action = action;
            }

            protected override UniTask ExecuteAsync(CommandContext outerContext)
            {
                action?.Invoke();
                return UniTask.CompletedTask;
            }
        }

        private sealed class AsyncActionCommand : CommandBase
        {
            private readonly Func<UniTask> asyncAction;

            public AsyncActionCommand(Func<UniTask> asyncAction)
            {
                this.asyncAction = asyncAction;
            }

            protected override async UniTask ExecuteAsync(CommandContext outerContext)
            {
                if (asyncAction != null)
                    await asyncAction();
            }
        }

        private sealed class WaitForSignalCommand : CommandBase
        {
            private readonly UniTaskCompletionSource tcs;

            public WaitForSignalCommand(UniTaskCompletionSource tcs)
            {
                this.tcs = tcs;
            }

            protected override async UniTask ExecuteAsync(CommandContext outerContext)
            {
                await tcs.Task;
            }
        }
    }
}