/**
 * 設置元素的src
 * @param {any} canvasId canvasId的dom id
 * @param {any} videoId video的dom id
 * @param {any} srcId img的dom id
 * @param {any} widht 設置截圖寬度
 * @param {any} height 設置截圖高度
 */
function setImgSrc(dest,videoId, srcId, widht, height) {
    let video = document.getElementById(videoId);
    let canvas = document.getElementById(canvasId);
    console.log(video.clientHeight, video.clientWidth);
   
    canvas.getContext('2d').drawImage(video, 0, 0, widht, height);

    canvas.toBlob(function (blob) {
        var src = document.getElementById(srcId);
        src.setAttribute("height", height)
        src.setAttribute("width", widht);
        src.setAttribute("src", URL.createObjectURL(blob))
    }, "image/jpeg", 0.95);
}
/**
 * 初始化攝像頭
 * @param {any} src 
 */
function startVideo(src) {
    if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
        navigator.mediaDevices.getUserMedia({ video: true }).then(function (stream) {
            let video = document.getElementById(src);
            if ("srcObject" in video) {
                video.srcObject = stream;
            } else {
                video.src = window.URL.createObjectURL(stream);
            }
            video.onloadedmetadata = function (e) {
                video.play();
            };
            //mirror image
            video.style.webkitTransform = "scaleX(-1)";
            video.style.transform = "scaleX(-1)";
        });
    }
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android">
	<application android:allowBackup="true" android:supportsRtl="true"></application>
	<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
	<uses-permission android:name="android.permission.INTERNET" />
	<!--相機權限-->
	<uses-permission android:name="android.permission.CAMERA" android:required="false"/>
	<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
	<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
	<!--相機功能-->
	<uses-feature android:name="android.hardware.camera" />
	<!--音頻錄制權限-->
	<uses-permission android:name="android.permission.RECORD_AUDIO" />
	<!--位置權限-->
	<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
	
	<!-- Needed only if your app targets Android 5.0 (API level 21) or higher. -->
	<uses-feature android:name="android.hardware.location.gps" />

	<queries>
		<intent>
			<action android:name="android.intent.action.VIEW" />
			<data android:scheme="http"/>
		</intent>
		<intent>
			<action android:name="android.intent.action.VIEW" />
			<data android:scheme="https"/>
		</intent>
	</queries>
</manifest>

[Activity(Theme = "@style/Maui.SplashTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation | ConfigChanges.UiMode | ConfigChanges.ScreenLayout | ConfigChanges.SmallestScreenSize | ConfigChanges.Density)]
public class MainActivity : MauiAppCompatActivity
{
    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);
        Platform.Init(this, savedInstanceState);
        // 申請所需權限 也可以再使用的時候去申請
        ActivityCompat.RequestPermissions(this, new[] { Manifest.Permission.Camera, Manifest.Permission.RecordAudio, Manifest.Permission.ModifyAudioSettings }, 0);
    }
}

#if ANDROID
using Android.Webkit;
using Microsoft.AspNetCore.Components.WebView.Maui;

namespace MainSample;

public class MauiWebChromeClient : WebChromeClient
{
    public override void OnPermissionRequest(PermissionRequest request)
    {
        request.Grant(request.GetResources());
    }
}

public class MauiBlazorWebViewHandler : BlazorWebViewHandler
{
    protected override void ConnectHandler(Android.Webkit.WebView platformView)
    {
        platformView.SetWebChromeClient(new MauiWebChromeClient());
        base.ConnectHandler(platformView);
    }
}

#endif

#if ANDROID
        builder.ConfigureMauiHandlers(handlers =>
        {
            handlers.AddHandler<IBlazorWebView, MauiBlazorWebViewHandler>();
        });
#endif

@page "/" @*界面路由*@

@inject IJSRuntime JSRuntime @*注入jsRuntime*@

@if(OpenCameraStatus) @*在攝像頭沒有被打開的情況不顯示video*@
{
    <video id="@VideoId" width="@widht" height="@height" />
    <canvas class="d-none" id="@CanvasId" width="@widht" height="@height" />
}
<button @onclick="" style="margin:8px">打開攝像頭</button> 
@*因為攝像頭必須是用戶手動觸發如果界面是滑動進入無法直接調用方法打開攝像頭所以添加按鈕觸發*@
<button style="margin:8px">截圖</button> @*對視頻流截取一張圖*@

<img id="@ImgId" />

@code{
    private string CanvasId;
    private string ImgId;
    private string VideoId;
    private bool OpenCameraStatus;
    private int widht = 320;
    private int height = 500;

    private async Task OpenCamera()
    {
        if (!OpenCameraStatus)
        {
            // 由于打開攝像頭的條件必須是用戶手動觸發如果滑動切換到界面是無法觸發的
            await JSRuntime.InvokeVoidAsync("startVideo", "videoFeed");
            OpenCameraStatus = true;
            StateHasChanged();
        }
    }

    protected override async Task OnInitializedAsync()
    {
        // 初始化id
        ImgId = Guid.NewGuid().ToString("N");
        CanvasId = Guid.NewGuid().ToString("N");
        VideoId = Guid.NewGuid().ToString("N");
        await base.OnInitializedAsync();
    }

    private async Task Screenshot()
    {
        await JSRuntime.InvokeAsync<String>("setImgSrc", CanvasId,VideoId, ImgId, widht, height);
    }
}