using System;
using System.ComponentModel;
using System.Threading.Tasks;
using Prism.Commands;
using Prism.Mvvm;
using TeamAAS_VP.Interfaces;
using TeamAAS_VP.Models;

namespace TeamAAS_VP.Core.Robots
{
    /// <summary>
    /// Axis view-model for binding to View: provides Axis + / - commands, axis name and current position.
    /// </summary>
    public class AxisViewModel : BindableBase, IDisposable
    {
        private readonly IRobot _robot;
        private readonly string _axisName;
        private double _currentPosition;
        private double _step;

        public DelegateCommand AxisPlusCommand { get; private set; }
        public DelegateCommand AxisMinusCommand { get; private set; }

        /// <summary>
        /// 轴名称（X/Y/Z/U）
        /// </summary>
        public string AxisName => _axisName;

        /// <summary>
        /// 当前轴位置（从 Robot 读取或命令后更新）
        /// </summary>
        public double CurrentPosition
        {
            get => _currentPosition;
            private set => SetProperty(ref _currentPosition, value);
        }

        /// <summary>
        /// 每次 jog 的步长（可设置）
        /// </summary>
        public double Step
        {
            get => _step;
            set
            {
                if (SetProperty(ref _step, value))
                {
                    RaiseCanExecuteChanged();
                }
            }
        }

        public AxisViewModel(string axisName, IRobot robot, double step = 1.0)
        {
            if (string.IsNullOrWhiteSpace(axisName)) throw new ArgumentNullException(nameof(axisName));
            _axisName = axisName.ToUpper();
            _robot = robot ?? throw new ArgumentNullException(nameof(robot));
            _step = step;

            AxisPlusCommand = DelegateCommand.FromAsyncHandler(ExecutePlusAsync, CanExecuteCommands);
            AxisMinusCommand = DelegateCommand.FromAsyncHandler(ExecuteMinusAsync, CanExecuteCommands);

            // 尝试初始化当前位置（异步，不阻塞构造）
            Task.Run(async () => await UpdatePositionFromRobotAsync());

            // 订阅机器人属性变化以刷新命令可用性
            if (_robot is INotifyPropertyChanged npc)
            {
                npc.PropertyChanged += Robot_PropertyChanged;
            }
        }

        private void Robot_PropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            // 监听 CanExecute 或 IsConnected 等关键属性名（Robots 中使用 CanExecute 字段）
            if (string.Equals(e.PropertyName, nameof(XYZU_Robot.CanExecute), StringComparison.OrdinalIgnoreCase) ||
                string.Equals(e.PropertyName, nameof(IRobot.CanExecute), StringComparison.OrdinalIgnoreCase) ||
                string.Equals(e.PropertyName, nameof(IRobot.IsConnected), StringComparison.OrdinalIgnoreCase))
            {
                RaiseCanExecuteChanged();
            }
        }

        private bool CanExecuteCommands()
        {
            try
            {
                if (_robot == null) return false;

                // 优先使用机器人公开的 CanExecute 属性（若存在），否则回退到 IsConnected
                var canExecuteProp = _robot.GetType().GetProperty("CanExecute");
                if (canExecuteProp != null && canExecuteProp.PropertyType == typeof(bool))
                {
                    return (bool)canExecuteProp.GetValue(_robot);
                }

                return _robot.IsConnected;
            }
            catch
            {
                return false;
            }
        }

        private void RaiseCanExecuteChanged()
        {
            AxisPlusCommand.RaiseCanExecuteChanged();
            AxisMinusCommand.RaiseCanExecuteChanged();
        }

        private async Task ExecutePlusAsync()
        {
            if (!CanExecuteCommands()) return;

            try
            {
                await _robot.JogAsync(_axisName, Step);
            }
            catch
            {
                // 忽略错误，视需求可扩展日志或通知
            }

            await UpdatePositionFromRobotAsync();
        }

        private async Task ExecuteMinusAsync()
        {
            if (!CanExecuteCommands()) return;

            try
            {
                await _robot.JogAsync(_axisName, -Step);
            }
            catch
            {
                // 忽略错误
            }

            await UpdatePositionFromRobotAsync();
        }

        /// <summary>
        /// 从 Robot 读取完整位置并更新当前轴的 CurrentPosition
        /// </summary>
        public async Task UpdatePositionFromRobotAsync()
        {
            try
            {
                var pos = await _robot.GetRobotPosAsync();
                if (pos == null) return;

                switch (_axisName)
                {
                    case "X":
                        CurrentPosition = pos.X;
                        break;
                    case "Y":
                        CurrentPosition = pos.Y;
                        break;
                    case "Z":
                        CurrentPosition = pos.Z;
                        break;
                    case "U":
                        CurrentPosition = pos.U;
                        break;
                    default:
                        // 未知轴，保持不变
                        break;
                }
            }
            catch
            {
                // 忽略读取错误
            }
        }

        public void Dispose()
        {
            if (_robot is INotifyPropertyChanged npc)
            {
                npc.PropertyChanged -= Robot_PropertyChanged;
            }
        }
    }
}