using System;
using System.Collections.Generic;
using System.IO.Ports;
using UnityEngine;
using UnityEngine.UI;

namespace Aisu.CardReader.Samples
{
    /// <summary>用于 Windows 实机联调的最小 Unity UI 示例。</summary>
    public sealed class CardReaderSampleUI : MonoBehaviour
    {
        [SerializeField] private Dropdown portDropdown;
        [SerializeField] private Button refreshButton;
        [SerializeField] private Button openButton;
        [SerializeField] private Button closeButton;
        [SerializeField] private Text stateText;
        [SerializeField] private Text portText;
        [SerializeField] private Text cardTypeText;
        [SerializeField] private Text cardNumberText;
        [SerializeField] private Text lastEventTimeText;
        [SerializeField] private Text errorText;
        [SerializeField] private Text logText;
        private readonly List<string> portNames = new List<string>();
        private readonly List<string> logLines = new List<string>();
        private CardReaderManager manager;
        private bool operationInProgress;
        private bool destroying;
        private bool apiSubscribed;

        private void Awake()
        {
            manager = CardReaderManager.Instance;
            SetText(stateText, "状态：未连接");
            SetText(portText, "端口：-");
            SetText(cardTypeText, "CardType：-");
            SetText(cardNumberText, "CardNumber：-");
            SetText(lastEventTimeText, "最后事件：-");
            SetText(errorText, "错误：-");
            SetText(logText, "日志：-");
        }

        private void OnEnable()
        {
            refreshButton?.onClick.AddListener(RefreshPorts);
            openButton?.onClick.AddListener(OpenSelectedPort);
            closeButton?.onClick.AddListener(CloseReader);
            SubscribeApiEvents();
        }

        private void Start()
        {
            // Manager 与 Sample 的 Awake 顺序不应影响事件订阅和首次端口扫描。
            SubscribeApiEvents();
            RefreshPorts();
        }

        private void SubscribeApiEvents()
        {
            if (apiSubscribed) return;
            if (manager == null) manager = CardReaderManager.Instance;
            if (manager == null) return;

            CardReaderApi.OnConnected.AddListener(OnConnected);
            CardReaderApi.OnDisconnected.AddListener(OnDisconnected);
            CardReaderApi.OnStateChanged.AddListener(OnStateChanged);
            CardReaderApi.OnCardReceived.AddListener(OnCardReceived);
            CardReaderApi.OnError.AddListener(OnReaderError);
            apiSubscribed = true;
        }

        private void OnDisable()
        {
            refreshButton?.onClick.RemoveListener(RefreshPorts);
            openButton?.onClick.RemoveListener(OpenSelectedPort);
            closeButton?.onClick.RemoveListener(CloseReader);
            if (!apiSubscribed || manager == null) return;

            CardReaderApi.OnConnected.RemoveListener(OnConnected);
            CardReaderApi.OnDisconnected.RemoveListener(OnDisconnected);
            CardReaderApi.OnStateChanged.RemoveListener(OnStateChanged);
            CardReaderApi.OnCardReceived.RemoveListener(OnCardReceived);
            CardReaderApi.OnError.RemoveListener(OnReaderError);
            apiSubscribed = false;
        }

        public void RefreshPorts()
        {
            if (destroying || operationInProgress) return;
            var previousPort = GetSelectedPort();
            portNames.Clear();
            portNames.AddRange(SerialPort.GetPortNames());
            portNames.Sort(StringComparer.OrdinalIgnoreCase);
            if (portDropdown != null)
            {
                var options = portNames.Count == 0
                    ? new List<string> { "No Ports" }
                    : new List<string>(portNames);
                portDropdown.ClearOptions();
                portDropdown.AddOptions(options);
                var selectedIndex = previousPort == null ? 0 : portNames.IndexOf(previousPort);
                portDropdown.value = selectedIndex < 0 ? 0 : selectedIndex;
                portDropdown.RefreshShownValue();
            }
            SetText(portText, portNames.Count == 0 ? "端口：未发现串口" : "端口：" + GetSelectedPort());
            if (portNames.Count == 0) SetStateText("未发现串口");
            AppendLog(portNames.Count == 0 ? "未发现可用串口。" : "发现串口：" + string.Join(", ", portNames));
            UpdateButtons();
        }

        public void OpenSelectedPort()
        {
            if (destroying || operationInProgress || manager == null || portDropdown == null || portNames.Count == 0)
                return;

            operationInProgress = true;
            UpdateButtons();
            try
            {
                var selectedPort = GetSelectedPort();
                if (string.IsNullOrEmpty(selectedPort)) return;
                var current = manager.SerialOptions;
                manager.SerialOptions = new SerialDeviceOptions
                {
                    PortName = selectedPort, BaudRate = current.BaudRate,
                    Parity = current.Parity, DataBits = current.DataBits, StopBits = current.StopBits,
                    Handshake = current.Handshake, RtsEnable = current.RtsEnable, DtrEnable = current.DtrEnable,
                    ReadTimeout = current.ReadTimeout, WriteTimeout = current.WriteTimeout,
                    AutoReconnect = current.AutoReconnect, ReconnectInterval = current.ReconnectInterval,
                    MaxPendingSendCount = current.MaxPendingSendCount
                };
                CardReaderApi.Open();
                SetText(portText, "端口：" + selectedPort);
                AppendLog("已打开读卡器：" + selectedPort);
            }
            catch (Exception exception) { ShowError("连接失败", exception); }
            finally { operationInProgress = false; UpdateButtons(); }
        }

        public void CloseReader()
        {
            if (destroying || operationInProgress || manager == null) return;
            operationInProgress = true;
            try
            {
                CardReaderApi.Close();
                AppendLog("已关闭读卡器。");
            }
            catch (Exception exception) { ShowError("断开失败", exception); }
            finally { operationInProgress = false; UpdateButtons(); }
        }

        private void OnConnected()
        {
            SetStateText("Connected");
            AppendLog("读卡器已连接。");
            UpdateButtons();
        }

        private void OnDisconnected()
        {
            SetStateText("Disconnected");
            AppendLog("读卡器已断开。");
            UpdateButtons();
        }

        private void OnStateChanged(SerialDeviceState state)
        {
            SetStateText(state.ToString());
            AppendLog("状态：" + state);
            UpdateButtons();
        }

        private void OnCardReceived(CardInfo card)
        {
            SetText(cardTypeText, $"CardType：{card.CardType} (0x{card.CardTypeCode:X2})");
            SetText(cardNumberText, $"CardNumber：{card.CardNumber}");
            SetText(lastEventTimeText, $"最后事件：{DateTime.Now:yyyy-MM-dd HH:mm:ss.fff}");
            AppendLog("收到卡片：" + card.CardNumber);
        }
        private void OnReaderError(CardReaderErrorEventArgs args) { ShowError("Transport/Core 错误", args.Exception); }

        private void OnDestroy()
        {
            destroying = true;
        }

        private void UpdateButtons()
        {
            var connected = manager != null && manager.IsConnected;
            if (refreshButton != null) refreshButton.interactable = !operationInProgress && !connected;
            if (openButton != null) openButton.interactable = !operationInProgress && !connected && portNames.Count > 0;
            if (closeButton != null) closeButton.interactable = !operationInProgress && connected;
        }

        private void ShowError(string message, Exception exception)
        {
            var text = exception == null ? message : message + "：" + FormatException(exception);
            SetText(errorText, "错误：" + text);
            AppendLog(text);
            Debug.LogError("[AISU 830T Sample] " + text, this);
        }

        private string GetSelectedPort()
        {
            if (portDropdown == null || portDropdown.value < 0 || portDropdown.value >= portNames.Count)
                return null;
            return portNames[portDropdown.value];
        }

        private void SetStateText(string state) { SetText(stateText, "状态：" + state); }

        private void AppendLog(string message)
        {
            if (logText == null) return;
            logLines.Add(DateTime.Now.ToString("HH:mm:ss.fff") + " " + message);
            if (logLines.Count > 40) logLines.RemoveAt(0);
            SetText(logText, "日志：\n" + string.Join("\n", logLines));
        }

        private static string FormatException(Exception exception)
        {
            var current = exception;
            var result = exception.GetType().Name + ": " + exception.Message;
            while (current.InnerException != null)
            {
                current = current.InnerException;
                result += " | " + current.GetType().Name + ": " + current.Message;
            }
            return result;
        }

        private static void SetText(Text target, string value) { if (target != null) target.text = value; }
    }
}