// D:\Project\Unity\webrtc\Assets\Script\MultiParticipantHostSample.cs
using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;

namespace Unity.RenderStreaming
{
    /// <summary>
    /// 多Participant Host示例
    /// Host显示自己的本地画面，同时为每个加入的Participant动态创建RawImage显示其远程画面
    /// 
    /// 使用方法：
    /// 1. 将此脚本挂载到场景中的GameObject上
    /// 2. 在Inspector中关联各字段
    /// 3. participantVideoContainer 需要挂载 GridLayoutGroup 或 VerticalLayoutGroup
    /// </summary>
    [RequireComponent(typeof(HostConnection))]
    public class MultiParticipantHostSample : MonoBehaviour
    {
#pragma warning disable 0649
        [Header("核心组件")]
        [SerializeField] private SignalingManager renderStreaming;
        [SerializeField] private HostConnection hostConnection;

        [Header("Host本地视频")]
        [SerializeField] private VideoStreamSender videoStreamSender;
        [SerializeField] private AudioStreamSender microphoneStreamer;
        [SerializeField] private RawImage localVideoImage;
        [SerializeField] private Toggle audioLoopbackToggle;
        [Header("Participant视频容器")]
        [Tooltip("用于放置动态创建的Participant视频UI的父物体，需挂载LayoutGroup")]
        [SerializeField] private Transform participantVideoContainer;

        [Header("UI控件")]
        [SerializeField] private Button startButton;
        [SerializeField] private Button setUpButton;
        [SerializeField] private Button hangUpButton;
        [SerializeField] private InputField connectionIdInput;
        [SerializeField] private Dropdown webcamSelectDropdown;
        [SerializeField] private Dropdown microphoneSelectDropdown;

#pragma warning restore 0649

        private string connectionId;
        private RenderStreamingSettings settings;

        /// <summary>
        /// 每个Participant的UI信息
        /// </summary>
        private Dictionary<string, ParticipantUI> participantUIs = new Dictionary<string, ParticipantUI>();

        private class ParticipantUI
        {
            public GameObject root;
            public RawImage videoImage;
            public Text nameLabel;
        }

        void Awake()
        {
            startButton.interactable = true;
            // 初始化UI
            setUpButton.interactable = true;
            hangUpButton.interactable = false;
            connectionIdInput.interactable = true;
            startButton.onClick.AddListener(() =>
            {
                videoStreamSender.enabled = true;
                startButton.interactable = false;
                webcamSelectDropdown.interactable = false;
                microphoneStreamer.enabled = true;
                microphoneSelectDropdown.interactable = false;
                setUpButton.interactable = true;
            });
            setUpButton.onClick.AddListener(SetUp);
            hangUpButton.onClick.AddListener(HangUp);
            connectionIdInput.onValueChanged.AddListener(input => connectionId = input);
            connectionIdInput.text = $"{Random.Range(0, 99999):D5}";

            // 本地视频：Sender启动后显示
            videoStreamSender.OnStartedStream += id =>
            {
                if (videoStreamSender.sourceWebCamTexture != null)
                    localVideoImage.texture = videoStreamSender.sourceWebCamTexture;
            };

            // 订阅HostConnection事件
            hostConnection.OnParticipantConnected += HandleParticipantConnected;
            hostConnection.OnParticipantDisconnected += HandleParticipantDisconnected;

            if (settings == null)
                settings = new RenderStreamingSettings();
            if (settings != null)
            {
                videoStreamSender.width = (uint)settings.StreamSize.x;
                videoStreamSender.height = (uint)settings.StreamSize.y;
            }
            
            audioLoopbackToggle.onValueChanged.AddListener(isOn =>
            {
                microphoneStreamer.loopback = isOn;
            });
            microphoneStreamer.OnStartedStream += id => microphoneStreamer.loopback = audioLoopbackToggle.isOn;
            microphoneSelectDropdown.onValueChanged.AddListener(index => microphoneStreamer.sourceDeviceIndex = index);
            microphoneSelectDropdown.options =
                Microphone.devices.Select(x => new Dropdown.OptionData(x)).ToList();
        }

        void Start()
        {
            if (renderStreaming.runOnAwake)
                return;
            if (settings != null)
                renderStreaming.useDefaultSettings = settings.UseDefaultSettings;
            if (settings?.SignalingSettings != null)
                renderStreaming.SetSignalingSettings(settings.SignalingSettings);
            renderStreaming.Run();
        }

        private void SetUp()
        {
            setUpButton.interactable = false;
            hangUpButton.interactable = true;
            connectionIdInput.interactable = false;

            videoStreamSender.enabled = true;

            if (settings != null)
                videoStreamSender.SetCodec(settings.SenderVideoCodec);

            hostConnection.CreateConnection(connectionId);
        }

        private void HangUp()
        {
            hostConnection.DeleteConnection(connectionId);

            // 清理所有Participant UI
            foreach (var ui in participantUIs.Values)
            {
                if (ui.root != null)
                    Destroy(ui.root);
            }
            participantUIs.Clear();

            localVideoImage.texture = null;
            setUpButton.interactable = true;
            hangUpButton.interactable = false;
            connectionIdInput.interactable = true;
            connectionIdInput.text = $"{Random.Range(0, 99999):D5}";
        }

        /// <summary>
        /// 新Participant连接成功回调
        /// 此时Participant的独立Receiver已创建，可以绑定视频显示
        /// </summary>
        private void HandleParticipantConnected(ParticipantStreams ps)
        {
            // 创建Participant UI
            var ui = CreateParticipantUI(ps.participantId);
            participantUIs[ps.participantId] = ui;

            // 绑定视频：当Receiver收到纹理时更新RawImage
            ps.videoReceiver.OnUpdateReceiveTexture += texture =>
            {
                ui.videoImage.color = Color.white;
                // 防止纹理为null时导致RawImage闪黑（重协商/track切换时可能短暂为null）
                if (ui.videoImage != null && texture != null)
                    ui.videoImage.texture = texture;
            };

            // 绑定音频：AudioSource已在HostConnection中配置
            ps.audioReceiver.OnUpdateReceiveAudioSource += source =>
            {
                if (source != null && !source.isPlaying)
                {
                    source.loop = true;
                    source.Play();
                }
            };

            Debug.Log($"[MultiParticipantHost] Participant UI created: {ps.participantId}");
        }

        /// <summary>
        /// Participant断开连接回调
        /// 销毁其UI
        /// </summary>
        private void HandleParticipantDisconnected(string participantId)
        {
            if (participantUIs.TryGetValue(participantId, out var ui))
            {
                if (ui.root != null)
                    Destroy(ui.root);
                participantUIs.Remove(participantId);
            }
            Debug.Log($"[MultiParticipantHost] Participant UI removed: {participantId}");
        }

        /// <summary>
        /// 动态创建单个Participant的视频显示UI
        /// 结构: [NameLabel] + [RawImage(视频画面)]
        /// </summary>
        private ParticipantUI CreateParticipantUI(string participantId)
        {
            var ui = new ParticipantUI();

            // 根节点
            ui.root = new GameObject($"ParticipantUI_{participantId}");
            ui.root.transform.SetParent(participantVideoContainer, false);
            // 添加VerticalLayoutGroup使内容垂直排列
            var vlg = ui.root.AddComponent<VerticalLayoutGroup>();
            vlg.childControlWidth = true;
            vlg.childControlHeight = false;
            vlg.childForceExpandWidth = true;
            vlg.childForceExpandHeight = false;
            vlg.spacing = 2;
            ui.root.transform.GetComponent<RectTransform>().anchorMin = Vector2.zero;
            ui.root.transform.GetComponent<RectTransform>().anchorMax = Vector2.one;
            // 名称标签
            var labelObj = new GameObject("NameLabel");
            labelObj.transform.SetParent(ui.root.transform, false);
            ui.nameLabel = labelObj.AddComponent<Text>();
            ui.nameLabel.text = $"Participant: {participantId}";
            ui.nameLabel.fontSize = 14;
            ui.nameLabel.color = Color.white;
            ui.nameLabel.alignment = TextAnchor.MiddleCenter;
            var labelLayout = labelObj.AddComponent<LayoutElement>();
            labelLayout.preferredHeight = 20;

            // 视频画面
            var imageObj = new GameObject("VideoImage");
            imageObj.transform.SetParent(ui.root.transform, false);
            ui.videoImage = imageObj.AddComponent<RawImage>();
            ui.videoImage.color = Color.black;
            var imageLayout = imageObj.AddComponent<LayoutElement>();
            imageLayout.preferredHeight = 200;

            // AspectRatioFitter保持视频比例
            var aspectRatio = imageObj.AddComponent<AspectRatioFitter>();
            aspectRatio.aspectMode = AspectRatioFitter.AspectMode.FitInParent;
            aspectRatio.aspectRatio = 16f / 9f;

            return ui;
        }

        void OnDestroy()
        {
            if (hostConnection != null)
            {
                hostConnection.OnParticipantConnected -= HandleParticipantConnected;
                hostConnection.OnParticipantDisconnected -= HandleParticipantDisconnected;
            }
        }
    }
}