/*
Copyright (c) 2019 The Khronos Group Inc.
Use of this source code is governed by an MIT-style license that can be
found in the LICENSE.txt file.
*/

function generateTest(internalFormat, pixelFormat, pixelType, prologue, resourcePath, defaultContextVersion) {
    var wtu = WebGLTestUtils;
    var tiu = TexImageUtils;
    var gl = null;
    var successfullyParsed = false;
    var redColor = [255, 0, 0];
    var greenColor = [0, 255, 0];

    function init()
    {
        description('Verify texImage3D and texSubImage3D code paths taking webgl canvas elements (' + internalFormat + '/' + pixelFormat + '/' + pixelType + ')');

        // Set the default context version while still allowing the webglVersion URL query string to override it.
        wtu.setDefault3DContextVersion(defaultContextVersion);
        gl = wtu.create3DContext("example");

        if (!prologue(gl)) {
            finishTest();
            return;
        }

        switch (gl[pixelFormat]) {
          case gl.RED:
          case gl.RED_INTEGER:
            greenColor = [0, 0, 0];
            break;
          default:
            break;
        }

        gl.clearColor(0,0,0,1);
        gl.clearDepth(1);

        runTest();
    }

    function setCanvasToRedGreen(ctx) {
      var width = ctx.canvas.width;
      var height = ctx.canvas.height;
      var halfHeight = Math.floor(height / 2);

      ctx.viewport(0, 0, width, height);

      ctx.enable(ctx.SCISSOR_TEST);
      ctx.scissor(0, 0, width, halfHeight);
      ctx.clearColor(1.0, 0, 0, 1.0);
      ctx.clear(ctx.COLOR_BUFFER_BIT);
      ctx.scissor(0, halfHeight, width, height - halfHeight);
      ctx.clearColor(0.0, 1.0, 0, 1.0);
      ctx.clear(ctx.COLOR_BUFFER_BIT);
      ctx.disable(ctx.SCISSOR_TEST);
    }

    function setCanvasTo257x257(ctx, bindingTarget) {
      ctx.canvas.width = 257;
      ctx.canvas.height = 257;
      setCanvasToRedGreen(ctx);
    }

    function setCanvasToMin(ctx, bindingTarget) {
      ctx.canvas.width = 1;
      ctx.canvas.height = 2;
      setCanvasToRedGreen(ctx);
    }

    function runOneIteration(canvas, flipY, program, bindingTarget, opt_texture)
    {
        var objType = 'canvas';
        if (canvas.transferToImageBitmap)
            objType = 'OffscreenCanvas';
        else if (canvas.parentNode)
            objType = 'canvas attached to DOM';
        debug('Testing flipY=' + flipY + ' object type: ' + objType +
              ' bindingTarget=' + (bindingTarget == gl.TEXTURE_3D ? 'TEXTURE_3D' : 'TEXTURE_2D_ARRAY') +
              ' canvas size: ' + canvas.width + 'x' + canvas.height + ' with red-green');

        gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
        if (!opt_texture) {
            var texture = gl.createTexture();
            // Bind the texture to texture unit 0
            gl.bindTexture(bindingTarget, texture);
            // Set up texture parameters
            gl.texParameteri(bindingTarget, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
            gl.texParameteri(bindingTarget, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
            gl.texParameteri(bindingTarget, gl.TEXTURE_WRAP_R, gl.CLAMP_TO_EDGE);
            gl.texParameteri(bindingTarget, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
            gl.texParameteri(bindingTarget, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
        } else {
            var texture = opt_texture;
        }
        // Set up pixel store parameters
        gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, flipY);
        gl.pixelStorei(gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL, false);
        wtu.failIfGLError(gl, 'gl.pixelStorei(gl.UNPACK_COLORSPACE_CONVERSION_WEBGL, gl.NONE);');

        // Upload the image into the texture
        // Initialize the texture to black first
        gl.texImage3D(bindingTarget, 0, gl[internalFormat], canvas.width, canvas.height, 1 /* depth */, 0,
                      gl[pixelFormat], gl[pixelType], null);
        gl.texSubImage3D(bindingTarget, 0, 0, 0, 0, canvas.width, canvas.height, 1 /* depth */,
                         gl[pixelFormat], gl[pixelType], canvas);

        var width = gl.canvas.width;
        var height = gl.canvas.height;
        var halfHeight = Math.floor(height / 2);
        var top = flipY ? (height - halfHeight) : 0;
        var bottom = flipY ? 0 : (height - halfHeight);

        // Draw the triangles
        wtu.clearAndDrawUnitQuad(gl, [0, 255, 0, 255]);

        // Check the top and bottom halves and make sure they have the right color.
        debug("Checking " + (flipY ? "top" : "bottom"));
        wtu.checkCanvasRect(gl, 0, bottom, width, halfHeight, redColor, "shouldBe " + redColor);
        debug("Checking " + (flipY ? "bottom" : "top"));
        wtu.checkCanvasRect(gl, 0, top, width, halfHeight, greenColor, "shouldBe " + greenColor);

        if (false) {
          var ma = wtu.makeImageFromCanvas(canvas);
          document.getElementById("console").appendChild(ma);

          var m = wtu.makeImageFromCanvas(gl.canvas);
          document.getElementById("console").appendChild(m);
          document.getElementById("console").appendChild(document.createElement("hr"));
        }

        return texture;
    }

    function runTest()
    {
        var ctx = wtu.create3DContext();
        var canvas = ctx.canvas;
        // Note: We use preserveDrawingBuffer:true to prevent canvas
        // visibility from interfering with the tests.
        var visibleCtx = wtu.create3DContext(null, { preserveDrawingBuffer:true });
        var visibleCanvas = visibleCtx.canvas;
        var descriptionNode = document.getElementById("description");
        document.body.insertBefore(visibleCanvas, descriptionNode);

        var cases = [
            { flipY: true,  ctx: ctx, init: setCanvasToMin },
            { flipY: false, ctx: ctx },
            { flipY: true,  ctx: ctx, init: setCanvasTo257x257 },
            { flipY: false, ctx: ctx },
            { flipY: true,  ctx: visibleCtx, init: setCanvasToMin},
            { flipY: false, ctx: visibleCtx },
        ];

        if (window.OffscreenCanvas) {
            var offscreen = new OffscreenCanvas(1, 1);
            var offscreenCtx = wtu.create3DContext(offscreen);
            cases = cases.concat([
                { flipY: true,  ctx: offscreenCtx, init: setCanvasToMin },
                { flipY: false, ctx: offscreenCtx },
            ]);
        }

        function runTexImageTest(bindingTarget) {
            var program;
            if (bindingTarget == gl.TEXTURE_3D) {
                program = tiu.setupTexturedQuadWith3D(gl, internalFormat);
            } else {
                program = tiu.setupTexturedQuadWith2DArray(gl, internalFormat);
            }

            return new Promise(function(resolve, reject) {
                var count = 4;
                var caseNdx = 0;
                var texture = undefined;
                function runNextTest() {
                    var c = cases[caseNdx];
                    if (c.init) {
                      c.init(c.ctx, bindingTarget);
                    }
                    texture = runOneIteration(c.ctx.canvas, c.flipY, program, bindingTarget, texture);
                    // for the first 2 iterations always make a new texture.
                    if (count < 2) {
                      gl.deleteTexture(texture);
                      texture = undefined;
                    }
                    ++caseNdx;
                    if (caseNdx == cases.length) {
                        caseNdx = 0;
                        --count;
                        if (!count) {
                            resolve("SUCCESS");
                            return;
                        }
                    }
                    wtu.waitForComposite(runNextTest);
                }
                runNextTest();
            });
        }

        runTexImageTest(gl.TEXTURE_3D).then(function(val) {
            runTexImageTest(gl.TEXTURE_2D_ARRAY).then(function(val) {
                wtu.glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");
                finishTest();
            });
        });
    }

    return init;
}