//////////////////////////////////////////////////////////////////////////////////////////
//          )                                                   (                       //
//       ( /(   (  (               )    (       (  (  (         )\ )    (  (            //
//       )\()) ))\ )(   (         (     )\ )    )\))( )\  (    (()/( (  )\))(  (        //
//      ((_)\ /((_|()\  )\ )      )\  '(()/(   ((_)()((_) )\ )  ((_)))\((_)()\ )\       //
//      | |(_|_))( ((_)_(_/(    _((_))  )(_))  _(()((_|_)_(_/(  _| |((_)(()((_|(_)      //
//      | '_ \ || | '_| ' \))  | '  \()| || |  \ V  V / | ' \)) _` / _ \ V  V (_-<      //
//      |_.__/\_,_|_| |_||_|   |_|_|_|  \_, |   \_/\_/|_|_||_|\__,_\___/\_/\_//__/      //
//                                 |__/                                                 //
//                       Copyright (c) 2021 Simon Schneegans                            //
//          Released under the GPLv3 or later. See LICENSE file for details.            //
//////////////////////////////////////////////////////////////////////////////////////////

'use strict';

const GObject = imports.gi.GObject;

const ExtensionUtils = imports.misc.extensionUtils;
const Me             = imports.misc.extensionUtils.getCurrentExtension();
const utils          = Me.imports.src.utils;

//////////////////////////////////////////////////////////////////////////////////////////
// This effect tears your windows apart with a series of violent scratches!             //
// This effect is not available on GNOME 3.3x, due to the limitation described in the   //
// documentation of vfunc_paint_target further down in this file.                       //
//////////////////////////////////////////////////////////////////////////////////////////

let TRexShader = null;

if (utils.isInShellProcess()) {

  const {Clutter, GdkPixbuf, Cogl} = imports.gi;
  const shaderSnippets             = Me.imports.src.shaderSnippets;


  TRexShader = GObject.registerClass({Properties: {}, Signals: {}},
                                     class TRexShader extends Clutter.ShaderEffect {
    _init(settings) {
      super._init({shader_type: Clutter.ShaderType.FRAGMENT_SHADER});

      // Load the claw texture. As the shader is re-created for each window animation,
      // this texture is also re-created each time. This could be improved in the future!
      // See assets/README.md for how this texture was created.
      const clawData    = GdkPixbuf.Pixbuf.new_from_resource('/img/claws.png');
      this._clawTexture = new Clutter.Image();
      this._clawTexture.set_data(
          clawData.get_pixels(), Cogl.PixelFormat.RGB_888, clawData.width,
          clawData.height, clawData.rowstride);

      const color =
          Clutter.Color.from_string(settings.get_string('claw-scratch-color'))[1];

      this.set_shader_source(`

// Inject some common shader snippets.
${shaderSnippets.standardUniforms()}
${shaderSnippets.noise()}

// See assets/README.md for how this texture was created.
uniform sampler2D uClawTexture;

const vec2  SEED            = vec2(${Math.random()}, ${Math.random()});
const float CLAW_SIZE       = ${settings.get_double('claw-scratch-scale')};
const float NUM_CLAWS       = ${settings.get_int('claw-scratch-count')};
const float WARP_INTENSITY  = 1.0 + ${settings.get_double('claw-scratch-warp')};
const float FLASH_INTENSITY = 0.1;
const float MAX_SPAWN_TIME  = 0.5; // Scratches will only start in the first half of the animation.
const float FF_TIME         = 0.5; // Relative time for the final fade to transparency.

// This method generates a grid of randomly rotated, slightly shifted and scaled 
// UV squares. It returns the texture coords of the UV square at the given actor
// coordinates. If these do not fall into one of the UV grids, the coordinates of
// the closest UV grid will be clamped and returned.
vec2 getClawUV(vec2 texCoords, float gridScale, vec2 seed) {

// Shift coordinates by a random offset and make sure the have a 1:1 aspect ratio.
vec2 coords = texCoords + hash2D(seed);
coords *= uSizeX < uSizeY ? vec2(1.0, 1.0 * uSizeY / uSizeX) : vec2(1.0 * uSizeX / uSizeY, 1.0);

// Apply global scale.
coords *= gridScale;

// Get grid cell coordinates in [0..1].
vec2 cellUV = mod(coords, vec2(1));

// This is unique for each cell.
vec2 cellID = coords-cellUV + vec2(362.456);

// Add random rotation, scale and offset to each grid cell.
float scale    = mix(0.8, 1.0,         hash(cellID*seed*134.451));
float offsetX  = mix(0.0, 1.0 - scale, hash(cellID*seed*54.4129));
float offsetY  = mix(0.0, 1.0 - scale, hash(cellID*seed*25.3089));
float rotation = mix(0.0, 2.0 * 3.141, hash(cellID*seed*2.99837));

cellUV -= vec2(offsetX, offsetY);
cellUV /= scale;

cellUV -= 0.5;
cellUV = vec2(cellUV.x * cos(rotation) - cellUV.y * sin(rotation),
cellUV.x * sin(rotation) + cellUV.y * cos(rotation));
cellUV += 0.5;

// Clamp resulting coordinates.
return clamp(cellUV, vec2(0), vec2(1));
}

void main() {

// Warp the texture coordinates to create a blow-up effect.
vec2 coords = cogl_tex_coord_in[0].st * 2.0 - 1.0;
float dist = length(coords);
coords = (coords/dist * pow(dist, WARP_INTENSITY)) * 0.5 + 0.5;
coords = mix(cogl_tex_coord_in[0].st, coords, uProgress);

// Accumulate several random scratches. The color in the scratch map refers to the
// relative time when the respective part will become invisible. Therefore we can
// add a value to make the scratch appear later.
float scratchMap = 1.0;
for (int i=0; i<NUM_CLAWS; ++i) {
vec2 uv = getClawUV(coords, 1.0/CLAW_SIZE, SEED*(i+1));
float delay = i/NUM_CLAWS * MAX_SPAWN_TIME;
scratchMap = min(scratchMap, clamp(texture2D(uClawTexture, uv).r + delay, 0, 1));
}

// Get the window texture. We shift the texture lookup by the local derivative of
// the claw texture in order to mimic some folding distortion.
vec2 offset = vec2(dFdx(scratchMap), dFdy(scratchMap)) * uProgress * 0.5;
cogl_color_out = texture2D(uTexture, coords + offset);

// Hide scratched out parts.
cogl_color_out *= (scratchMap > uProgress ? 1 : 0);

// Add colorful flashes.
float flashIntensity = 1.0 / FLASH_INTENSITY * (scratchMap - uProgress) + 1;
if (flashIntensity < 0 || flashIntensity >= 1) {
flashIntensity = 0;
}

vec3 flashColor = vec3(${color.red / 255},
${color.green / 255},
${color.blue / 255}) * ${color.alpha / 255};

cogl_color_out.rgb += flashIntensity * mix(flashColor, vec3(0), uProgress);

// Fade out the remaining shards.
float fade = smoothstep(0, 1, 1 - clamp((uProgress - 1.0 + FF_TIME)/FF_TIME, 0, 1));
cogl_color_out *= fade;

// These are pretty useful for understanding how this works.
// cogl_color_out = vec4(vec3(flashIntensity), 1);
// cogl_color_out = vec4(vec3(scratchMap), 1);
}
`);
    };

    // This is overridden to bind the claw texture for drawing. Sadly, this seems to be
    // impossible under GNOME 3.3x as this.get_pipeline() is not available. It was called
    // get_target() back then but this is not wrapped in GJS.
    // https://gitlab.gnome.org/GNOME/mutter/-/blob/gnome-3-36/clutter/clutter/clutter-offscreen-effect.c#L598
    vfunc_paint_target(node, paint_context) {
      const pipeline = this.get_pipeline();
      pipeline.set_layer_texture(1, this._clawTexture.get_texture());
      this.set_uniform_value('uClawTexture', 1);
      super.vfunc_paint_target(node, paint_context);
    }
  });
}

var TRexEffect = class TRexEffect {

  // ---------------------------------------------------------------------- static methods

  static getMinShellVersion() {
    return [40, 0];
  }

  static getSettingsPrefix() {
    return 'trex';
  }

  static getLabel() {
    return 'T-Rex Attack';
  }

  static initPreferences(dialog) {

    dialog.getBuilder().add_from_resource('/ui/gtk4/trexPage.ui');

    // Bind all properties.
    dialog.bindAdjustment('trex-animation-time');
    dialog.bindColorButton('claw-scratch-color');
    dialog.bindAdjustment('claw-scratch-scale');
    dialog.bindAdjustment('claw-scratch-count');
    dialog.bindAdjustment('claw-scratch-warp');

    const stack = dialog.getBuilder().get_object('main-stack');
    stack.add_titled(
        dialog.getBuilder().get_object('trex-prefs'), 'trex', 'T-Rex Attack');
  }

  static createShader(settings) {
    return new TRexShader(settings);
  }

  // If there's a transition in progress, we re-target these transitions so that the
  // window is neither scaled nor faded.
  static tweakTransitions(actor, settings) {
    const animationTime = settings.get_int('trex-animation-time');

    const tweakTransition = (property, value) => {
      const transition = actor.get_transition(property);
      if (transition) {
        transition.set_to(value);
        transition.set_duration(animationTime);
      }
    };

    const warp = 0.5 * settings.get_double('claw-scratch-warp');

    tweakTransition('opacity', 255);
    tweakTransition('scale-x', 1.0 + warp);
    tweakTransition('scale-y', 1.0 + warp);
  }
}