import { getPath } from "./common.js";
import { makeSliders } from "./fontSliders.js";
import { updateSliders } from "./slider.js";

class FontRenderer {
  createBuffers(device)
  {
    this.frames = [];

    //////////////////////////////////////////////////////////////////////
    // glyph
    //////////////////////////////////////////////////////////////////////

    const glyphBufferSize = this.exports.font_layout__glyph_buffer_size(this.fontLayoutAddress);
    const glyphBuffer = device.createBuffer({
      label: `glyph buffer`,
      size: glyphBufferSize,
      usage: GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_DST,
    });

    const glyphBufferAddress = this.exports.font_layout__glyph_buffer_address(this.fontLayoutAddress);
    device.queue.writeBuffer(glyphBuffer, 0,
                             this.module.memory.buffer, glyphBufferAddress, glyphBufferSize);

    //////////////////////////////////////////////////////////////////////
    // texture
    //////////////////////////////////////////////////////////////////////

    const textureWidth = this.exports.font_layout__texture_width(this.fontLayoutAddress);
    const textureHeight = this.exports.font_layout__texture_height(this.fontLayoutAddress);
    const textureAddress = this.exports.font_layout__texture_address(this.fontLayoutAddress);

    //console.log(textureWidth, textureHeight, textureAddress);
    const texture = device.createTexture({
      size: [textureWidth, textureHeight],
      format: 'r8unorm',
      usage: GPUTextureUsage.TEXTURE_BINDING | GPUTextureUsage.COPY_DST,
    });

    device.queue.writeTexture({ texture: texture },
                              this.module.memory.buffer,
                              { offset: textureAddress, bytesPerRow: textureWidth },
                              { width: textureWidth, height: textureHeight });

    //////////////////////////////////////////////////////////////////////
    // sampler
    //////////////////////////////////////////////////////////////////////

    const sampler = device.createSampler({
      magFilter: "linear",
      minFilter: "linear",
    });

    //////////////////////////////////////////////////////////////////////
    // bind group
    //////////////////////////////////////////////////////////////////////

    this.perFontBindGroup = device.createBindGroup({
      label: `font per-font bind group`,
      layout: this.bindGroupLayout.perFont,
      entries: [{
        binding: 0,
        resource: sampler,
      }, {
        binding: 1,
        resource: texture,
      }, {
        binding: 2,
        resource: { buffer: glyphBuffer },
      }]
    });

    //////////////////////////////////////////////////////////////////////
    // per-frame (layout, configuration)
    //////////////////////////////////////////////////////////////////////

    this.layoutBufferAddress = this.exports.font_layout__layout_buffer_address(this.fontLayoutAddress);

    const layoutBufferSize = this.exports.font_layout__layout_buffer_size(this.fontLayoutAddress);
    for (let i = 0; i < 2; i++) {
      const layoutBuffer = device.createBuffer({
        label: `layout buffer ${i}`,
        size: layoutBufferSize,
        usage: GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_DST,
      });

      const configurationBuffer = device.createBuffer({
        label: `configuration buffer ${i}`,
        size: this.sliderArray.byteLength,
        usage: GPUBufferUsage.UNIFORM | GPUBufferUsage.COPY_DST,
      });

      const bindGroup = device.createBindGroup({
        label: `font per-frame bind group ${i}`,
        layout: this.bindGroupLayout.perFrame,
        entries: [{
          binding: 0,
          resource: { buffer: layoutBuffer },
        }, {
          binding: 1,
          resource: { buffer: configurationBuffer },
        }]
      });

      this.frames.push({
        layoutBuffer: layoutBuffer,
        configurationBuffer: configurationBuffer,
        bindGroup: bindGroup,
      });
    }
  }

  constructor(device, canvasFormat, viewUniformBuffer, wgsl, module, fontBufferSrc)
  {
    const label = "font";

    this.module = module;
    this.exports = module.instance.exports;

    //////////////////////////////////////////////////////////////////////
    // font layout
    //////////////////////////////////////////////////////////////////////

    this.fontBufferAddress = this.exports.mem_alloc(fontBufferSrc.byteLength);
    const fontBufferDst = new Uint8Array(this.module.memory.buffer, this.fontBufferAddress, fontBufferSrc.byteLength);
    fontBufferDst.set(new Uint8Array(fontBufferSrc));
    this.maxGlyphs = 1024;
    this.fontLayoutAddress = this.exports.font_layout__create(this.fontBufferAddress, this.maxGlyphs);

    //////////////////////////////////////////////////////////////////////
    // shader module
    //////////////////////////////////////////////////////////////////////

    const shaderModule = device.createShaderModule({
      label: `${label} shader`,
      code: wgsl,
    });

    //////////////////////////////////////////////////////////////////////
    // index buffer
    //////////////////////////////////////////////////////////////////////

    const array = new Uint16Array(6);
    array[0] = 0;
    array[1] = 1;
    array[2] = 2;
    array[3] = 0;
    array[4] = 3;
    array[5] = 1;

    this.buffer = device.createBuffer({
      label: `${label} renderer buffer`,
      size: array.byteLength,
      usage: GPUBufferUsage.INDEX | GPUBufferUsage.COPY_DST,
    });

    device.queue.writeBuffer(this.buffer, 0, array, 0, array.length);

    //////////////////////////////////////////////////////////////////////
    // pipeline
    //////////////////////////////////////////////////////////////////////

    this.bindGroupLayout = {
      view: device.createBindGroupLayout({
        label: `${label} bind group layout view`,
        entries: [{
          binding: 0,
          visibility: GPUShaderStage.VERTEX,
          buffer: { type: "uniform" }
        }]
      }),
      perFont: device.createBindGroupLayout({
        label: `${label} bind group per-font`,
        entries: [
          { // sampler
            binding: 0,
            visibility: GPUShaderStage.FRAGMENT,
            sampler: {}
          }, { // texture
            binding: 1,
            visibility: GPUShaderStage.FRAGMENT,
            texture: {},
          }, { // glyph buffer
            binding: 2,
            visibility: GPUShaderStage.VERTEX | GPUShaderStage.FRAGMENT,
            buffer: { type: "read-only-storage" }
          }
        ]
      }),
      perFrame: device.createBindGroupLayout({
        label: `${label} bind group per-frame`,
        entries: [{ // layout buffer
          binding: 0,
          visibility: GPUShaderStage.VERTEX,
          buffer: { type: "read-only-storage" }
        }, { // configuration
          binding: 1,
          visibility: GPUShaderStage.VERTEX | GPUShaderStage.FRAGMENT,
          buffer: { type: "uniform" }
        }]
      }),
    };

    const pipelineLayout = device.createPipelineLayout({
      label: `${label} pipeline layout`,
      bindGroupLayouts: [
        this.bindGroupLayout.view,
        this.bindGroupLayout.perFont,
        this.bindGroupLayout.perFrame,
      ],
    });

    console.log(canvasFormat);
    this.renderPipeline = device.createRenderPipeline({
      label: `${label} pipeline`,
      layout: pipelineLayout,
      vertex: {
        module: shaderModule,
        entryPoint: "vertexMain",
      },
      fragment: {
        module: shaderModule,
        entryPoint: "fragmentMain",
        targets: [{
          blend: {
            color: {
              dstFactor: "one-minus-src-alpha",
              srcFactor: "src-alpha",
            },
            alpha: {
              dstFactor: "one-minus-src-alpha",
              srcFactor: "src-alpha",
            },
            operation: "add",
          },
          format: canvasFormat,
        }]
      },
      primitive: {
        topology: "triangle-list",
      },
      depthStencil: {
        depthWriteEnabled: true,
        depthCompare: "always",
        format: "depth24plus",
      },
    });

    //////////////////////////////////////////////////////////////////////
    // sliders
    //////////////////////////////////////////////////////////////////////

    this.sliders = makeSliders();
    this.sliderArray = new Float32Array(4 * 4);

    //////////////////////////////////////////////////////////////////////
    // buffers
    //////////////////////////////////////////////////////////////////////

    this.createBuffers(device);

    //////////////////////////////////////////////////////////////////////
    // bind group
    //////////////////////////////////////////////////////////////////////

    this.viewBindGroup = device.createBindGroup({
      label: `${label} bind group`,
      layout: this.bindGroupLayout.view,
      entries: [{
        binding: 0,
        resource: { buffer: viewUniformBuffer },
      }],
    });
  }

  update(device, frameNumber)
  {
    this.instanceCount = this.exports.font_layout__layout_buffer_index(this.fontLayoutAddress);
    const layoutBufferSize = this.instanceCount * 4 * 4;

    device.queue.writeBuffer(this.frames[frameNumber].layoutBuffer, 0,
                             this.module.memory.buffer, this.layoutBufferAddress, layoutBufferSize);

    //////////////////////////////////////////////////////////////////////
    // sliders
    //////////////////////////////////////////////////////////////////////

    const configuration = updateSliders(this.sliders);
    this.sliderArray[0] = configuration.scale;
    this.sliderArray[1] = configuration.translateX;
    this.sliderArray[2] = configuration.translateY;

    this.sliderArray[4] = configuration.distanceThreshold;
    this.sliderArray[5] = configuration.distanceScale;
    this.sliderArray[6] = configuration.distanceOffset;

    this.sliderArray[8] = configuration.outlineThreshold;
    this.sliderArray[9] = configuration.outlineScale;
    this.sliderArray[10] = configuration.outlineOffset;

    this.sliderArray[12] = configuration.colorMix;
    this.sliderArray[13] = configuration.colorScale;
    this.sliderArray[14] = configuration.colorOffset;

    device.queue.writeBuffer(this.frames[frameNumber].configurationBuffer, 0,
                             this.sliderArray);
  }

  render(renderPass, frameNumber)
  {
    renderPass.setPipeline(this.renderPipeline);
    renderPass.setIndexBuffer(this.buffer, "uint16");
    renderPass.setBindGroup(0, this.viewBindGroup);
    renderPass.setBindGroup(1, this.perFontBindGroup);
    renderPass.setBindGroup(2, this.frames[frameNumber].bindGroup);

    for (let i = 0; i < this.instanceCount; i++) {
      renderPass.drawIndexed(6, 1, 0, 0, i);
    }
  }
}

async function loadFont(device, canvasFormat, viewUniformBuffer, module)
{
  const fontWgsl = await getPath("font.wgsl");

  const liberationResponse = await fetch("liberation.data");
  const liberationBuffer = await liberationResponse.arrayBuffer();

  const renderer = new FontRenderer(device, canvasFormat, viewUniformBuffer, fontWgsl, module, liberationBuffer);

  module.instance.exports.font_layout__draw(renderer.fontLayoutAddress);

  return renderer;
}

export { loadFont };