export module ImageConver {
    export function ImageToBase64(Texture2D: cc.Texture2D): string {
        let image: ImageBitmap = Texture2D["_image"];
        let cv: HTMLCanvasElement = document.createElement("canvas");
        let context: CanvasRenderingContext2D = cv.getContext("2d");
        cv.width = image.width || 128;
        cv.height = image.height || 128;
        context.drawImage(image, 0, 0, image.width || 128, image.height || 128);
        let DataURL: string = cv.toDataURL();
        return DataURL;
    }
    export function Base64toBlob(b64Data: any, contentType: string = "image/png", sliceSize: number = 512): Blob {
        let byteCharacters: string = atob(b64Data.substring(b64Data.indexOf(",") + 1));
        const byteArrays: any[] = [];
        for (let offset: number = 0; offset < byteCharacters.length; offset += sliceSize) {
            const slice: string = byteCharacters.slice(offset, offset + sliceSize);

            const byteNumbers: any[] = new Array(slice.length);
            for (let i: number = 0; i < slice.length; i++) {
                byteNumbers[i] = slice.charCodeAt(i);
            }
            const byteArray: Uint8Array = new Uint8Array(byteNumbers);
            byteArrays.push(byteArray);
        }
        const blob: Blob = new Blob(byteArrays, { type: contentType });
        return blob;
    }

    export function BlobToImageNode(BlobData: Blob, node: cc.Node): void {
        let reader: FileReader = new FileReader();
        reader.onloadend = function (): void {
            ImageConver.Base64ToImageNode(reader.result + "", node);
        };
        reader.readAsDataURL(BlobData);
    }

    export function Base64ToImageNode(base64: string, node: cc.Node): void {
        let image: HTMLImageElement = new Image();
        image.src = base64;
        image.onload = function (): void {
            let texture: cc.Texture2D = new cc.Texture2D();
            texture.initWithElement(image);
            texture.handleLoadedTexture();
            let spriteFrame: cc.SpriteFrame = new cc.SpriteFrame(texture);
            let sprite: cc.Sprite = node.addComponent(cc.Sprite);
            sprite.spriteFrame = spriteFrame;
            return;
        };
    }

    export function Node2Base64(nodeCapture: cc.Node): string {
        let nodeCamera: cc.Node = new cc.Node();
        nodeCamera.parent = cc.find("Canvas");
        let camera: cc.Camera = nodeCamera.addComponent(cc.Camera);

        let position: cc.Vec2 = nodeCapture.getPosition();
        let width: number = nodeCapture.width;
        let height: number = nodeCapture.height;

        // 当 alignWithScreen 为 true 的时候，摄像机会自动将视窗大小调整为整个屏幕的大小。如果想要完全自由地控制摄像机，则需要将 alignWithScreen 设置为 false。（v2.2.1 新增）
        camera.alignWithScreen = false;
        // 设置摄像机的投影模式是正交（true）还是透视（false）模式
        camera.ortho = true;
        // 摄像机在正交投影模式下的视窗大小。该属性在 alignWithScreen 设置为 false 时生效。
        camera.orthoSize = height / 2;

        let texture: cc.RenderTexture = new cc.RenderTexture();
        // 如果截图内容中不包含 Mask 组件，可以不用传递第三个参数
        texture.initWithSize(width, height);

        // 如果设置了 targetTexture，那么摄像机渲染的内容不会输出到屏幕上，而是会渲染到 targetTexture 上。
        camera.targetTexture = texture;

        // 创建画布
        let canvas: HTMLCanvasElement = document.createElement("canvas");
        canvas.width = width;
        canvas.height = height;

        let ctx: CanvasRenderingContext2D = canvas.getContext("2d");

        nodeCapture.setPosition(cc.Vec2.ZERO);
        // 渲染一次摄像机，即更新一次内容到 RenderTexture 中
        camera.render(nodeCapture);
        nodeCapture.setPosition(position);

        // 从 render texture 读取像素数据，数据类型为 RGBA 格式的 Uint8Array 数组。
        // 默认每次调用此函数会生成一个大小为 （长 x 高 x 4） 的 Uint8Array。
        let data: Uint8Array = texture.readPixels();
        // write the render data
        // PNG 中 1 像素 = 32 bit（RGBA），1 byte = 8 bit，所以 1 像素 = 4 byte
        // 每行 width 像素，即 width * 4 字节
        let rowBytes: number = width * 4;
        for (let row: number = 0; row < height; row++) {
            // RenderTexture 得到的纹理是上下翻转的
            let srow: number = height - 1 - row;
            let imageData: ImageData = ctx.createImageData(width, 1);
            let start: number = srow * width * 4;
            for (let i: number = 0; i < rowBytes; i++) {
                imageData.data[i] = data[start + i];
            }

            ctx.putImageData(imageData, 0, row);
        }

        let dataURL: string = canvas.toDataURL("image/png");

        return dataURL;
    }
}