import {
	Vector2
} from 'three';

/**
 * @module BokehShader2
 * @three_import import { BokehShader, BokehDepthShader } from 'three/addons/shaders/BokehShader2.js';
 */

/**
 * Depth-of-field shader with bokeh ported from
 * [GLSL shader by Martins Upitis]{@link http://blenderartists.org/forum/showthread.php?237488-GLSL-depth-of-field-with-bokeh-v2-4-(update)}.
 *
 * Requires #define RINGS and SAMPLES integers
 *
 * @constant
 * @type {ShaderMaterial~Shader}
 */
const BokehShader = {

	name: 'BokehShader',

	uniforms: {

		'textureWidth': { value: 1.0 },
		'textureHeight': { value: 1.0 },

		'focalDepth': { value: 1.0 },
		'focalLength': { value: 24.0 },
		'fstop': { value: 0.9 },

		'tColor': { value: null },
		'tDepth': { value: null },

		'maxblur': { value: 1.0 },

		'showFocus': { value: 0 },
		'manualdof': { value: 0 },
		'vignetting': { value: 0 },
		'depthblur': { value: 0 },

		'threshold': { value: 0.5 },
		'gain': { value: 2.0 },
		'bias': { value: 0.5 },
		'fringe': { value: 0.7 },

		'znear': { value: 0.1 },
		'zfar': { value: 100 },

		'noise': { value: 1 },
		'dithering': { value: 0.0001 },
		'pentagon': { value: 0 },

		'shaderFocus': { value: 1 },
		'focusCoords': { value: new Vector2() }


	},

	vertexShader: /* glsl */`

		varying vec2 vUv;

		void main() {

			vUv = uv;
			gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );

		}`,

	fragmentShader: /* glsl */`

		#include <common>

		varying vec2 vUv;

		uniform sampler2D tColor;
		uniform sampler2D tDepth;
		uniform float textureWidth;
		uniform float textureHeight;

		uniform float focalDepth;  //focal distance value in meters, but you may use autofocus option below
		uniform float focalLength; //focal length in mm
		uniform float fstop; //f-stop value
		uniform bool showFocus; //show debug focus point and focal range (red = focal point, green = focal range)

		/*
		make sure that these two values are the same for your camera, otherwise distances will be wrong.
		*/

		uniform float znear; // camera clipping start
		uniform float zfar; // camera clipping end

		//------------------------------------------
		//user variables

		const int samples = SAMPLES; //samples on the first ring
		const int rings = RINGS; //ring count

		const int maxringsamples = rings * samples;

		uniform bool manualdof; // manual dof calculation
		float ndofstart = 1.0; // near dof blur start
		float ndofdist = 2.0; // near dof blur falloff distance
		float fdofstart = 1.0; // far dof blur start
		float fdofdist = 3.0; // far dof blur falloff distance

		float CoC = 0.03; //circle of confusion size in mm (35mm film = 0.03mm)

		uniform bool vignetting; // use optical lens vignetting

		float vignout = 1.3; // vignetting outer border
		float vignin = 0.0; // vignetting inner border
		float vignfade = 22.0; // f-stops till vignette fades

		uniform bool shaderFocus;
		// disable if you use external focalDepth value

		uniform vec2 focusCoords;
		// autofocus point on screen (0.0,0.0 - left lower corner, 1.0,1.0 - upper right)
		// if center of screen use vec2(0.5, 0.5);

		uniform float maxblur;
		//clamp value of max blur (0.0 = no blur, 1.0 default)

		uniform float threshold; // highlight threshold;
		uniform float gain; // highlight gain;

		uniform float bias; // bokeh edge bias
		uniform float fringe; // bokeh chromatic aberration / fringing

		uniform bool noise; //use noise instead of pattern for sample dithering

		uniform float dithering;

		uniform bool depthblur; // blur the depth buffer
		float dbsize = 1.25; // depth blur size

		/*
		next part is experimental
		not looking good with small sample and ring count
		looks okay starting from samples = 4, rings = 4
		*/

		uniform bool pentagon; //use pentagon as bokeh shape?
		float feather = 0.4; //pentagon shape feather

		//------------------------------------------

		float penta(vec2 coords) {
			//pentagonal shape
			float scale = float(rings) - 1.3;
			vec4  HS0 = vec4( 1.0,         0.0,         0.0,  1.0);
			vec4  HS1 = vec4( 0.309016994, 0.951056516, 0.0,  1.0);
			vec4  HS2 = vec4(-0.809016994, 0.587785252, 0.0,  1.0);
			vec4  HS3 = vec4(-0.809016994,-0.587785252, 0.0,  1.0);
			vec4  HS4 = vec4( 0.309016994,-0.951056516, 0.0,  1.0);
			vec4  HS5 = vec4( 0.0        ,0.0         , 1.0,  1.0);

			vec4  one = vec4( 1.0 );

			vec4 P = vec4((coords),vec2(scale, scale));

			vec4 dist = vec4(0.0);
			float inorout = -4.0;

			dist.x = dot( P, HS0 );
			dist.y = dot( P, HS1 );
			dist.z = dot( P, HS2 );
			dist.w = dot( P, HS3 );

			dist = smoothstep( -feather, feather, dist );

			inorout += dot( dist, one );

			dist.x = dot( P, HS4 );
			dist.y = HS5.w - abs( P.z );

			dist = smoothstep( -feather, feather, dist );
			inorout += dist.x;

			return clamp( inorout, 0.0, 1.0 );
		}

		float bdepth(vec2 coords) {
			// Depth buffer blur
			float d = 0.0;
			float kernel[9];
			vec2 offset[9];

			vec2 wh = vec2(1.0/textureWidth,1.0/textureHeight) * dbsize;

			offset[0] = vec2(-wh.x,-wh.y);
			offset[1] = vec2( 0.0, -wh.y);
			offset[2] = vec2( wh.x -wh.y);

			offset[3] = vec2(-wh.x,  0.0);
			offset[4] = vec2( 0.0,   0.0);
			offset[5] = vec2( wh.x,  0.0);

			offset[6] = vec2(-wh.x, wh.y);
			offset[7] = vec2( 0.0,  wh.y);
			offset[8] = vec2( wh.x, wh.y);

			kernel[0] = 1.0/16.0;   kernel[1] = 2.0/16.0;   kernel[2] = 1.0/16.0;
			kernel[3] = 2.0/16.0;   kernel[4] = 4.0/16.0;   kernel[5] = 2.0/16.0;
			kernel[6] = 1.0/16.0;   kernel[7] = 2.0/16.0;   kernel[8] = 1.0/16.0;


			for( int i=0; i<9; i++ ) {
				float tmp = texture2D(tDepth, coords + offset[i]).r;
				d += tmp * kernel[i];
			}

			return d;
		}


		vec3 color(vec2 coords,float blur) {
			//processing the sample

			vec3 col = vec3(0.0);
			vec2 texel = vec2(1.0/textureWidth,1.0/textureHeight);

			col.r = texture2D(tColor,coords + vec2(0.0,1.0)*texel*fringe*blur).r;
			col.g = texture2D(tColor,coords + vec2(-0.866,-0.5)*texel*fringe*blur).g;
			col.b = texture2D(tColor,coords + vec2(0.866,-0.5)*texel*fringe*blur).b;

			vec3 lumcoeff = vec3(0.299,0.587,0.114);
			float lum = dot(col.rgb, lumcoeff);
			float thresh = max((lum-threshold)*gain, 0.0);
			return col+mix(vec3(0.0),col,thresh*blur);
		}

		vec3 debugFocus(vec3 col, float blur, float depth) {
			float edge = 0.002*depth; //distance based edge smoothing
			float m = clamp(smoothstep(0.0,edge,blur),0.0,1.0);
			float e = clamp(smoothstep(1.0-edge,1.0,blur),0.0,1.0);

			col = mix(col,vec3(1.0,0.5,0.0),(1.0-m)*0.6);
			col = mix(col,vec3(0.0,0.5,1.0),((1.0-e)-(1.0-m))*0.2);

			return col;
		}

		float linearize(float depth) {
			return -zfar * znear / (depth * (zfar - znear) - zfar);
		}

		float vignette() {
			float dist = distance(vUv.xy, vec2(0.5,0.5));
			dist = smoothstep(vignout+(fstop/vignfade), vignin+(fstop/vignfade), dist);
			return clamp(dist,0.0,1.0);
		}

		float gather(float i, float j, int ringsamples, inout vec3 col, float w, float h, float blur) {
			float rings2 = float(rings);
			float step = PI*2.0 / float(ringsamples);
			float pw = cos(j*step)*i;
			float ph = sin(j*step)*i;
			float p = 1.0;
			if (pentagon) {
				p = penta(vec2(pw,ph));
			}
			col += color(vUv.xy + vec2(pw*w,ph*h), blur) * mix(1.0, i/rings2, bias) * p;
			return 1.0 * mix(1.0, i /rings2, bias) * p;
		}

		void main() {
			//scene depth calculation

			float depth = linearize(texture2D(tDepth,vUv.xy).x);

			// Blur depth?
			if ( depthblur ) {
				depth = linearize(bdepth(vUv.xy));
			}

			//focal plane calculation

			float fDepth = focalDepth;

			if (shaderFocus) {

				fDepth = linearize(texture2D(tDepth,focusCoords).x);

			}

			// dof blur factor calculation

			float blur = 0.0;

			if (manualdof) {
				float a = depth-fDepth; // Focal plane
				float b = (a-fdofstart)/fdofdist; // Far DoF
				float c = (-a-ndofstart)/ndofdist; // Near Dof
				blur = (a>0.0) ? b : c;
			} else {
				float f = focalLength; // focal length in mm
				float d = fDepth*1000.0; // focal plane in mm
				float o = depth*1000.0; // depth in mm

				float a = (o*f)/(o-f);
				float b = (d*f)/(d-f);
				float c = (d-f)/(d*fstop*CoC);

				blur = abs(a-b)*c;
			}

			blur = clamp(blur,0.0,1.0);

			// calculation of pattern for dithering

			vec2 noise = vec2(rand(vUv.xy), rand( vUv.xy + vec2( 0.4, 0.6 ) ) )*dithering*blur;

			// getting blur x and y step factor

			float w = (1.0/textureWidth)*blur*maxblur+noise.x;
			float h = (1.0/textureHeight)*blur*maxblur+noise.y;

			// calculation of final color

			vec3 col = vec3(0.0);

			if(blur < 0.05) {
				//some optimization thingy
				col = texture2D(tColor, vUv.xy).rgb;
			} else {
				col = texture2D(tColor, vUv.xy).rgb;
				float s = 1.0;
				int ringsamples;

				for (int i = 1; i <= rings; i++) {
					/*unboxstart*/
					ringsamples = i * samples;

					for (int j = 0 ; j < maxringsamples ; j++) {
						if (j >= ringsamples) break;
						s += gather(float(i), float(j), ringsamples, col, w, h, blur);
					}
					/*unboxend*/
				}

				col /= s; //divide by sample count
			}

			if (showFocus) {
				col = debugFocus(col, blur, depth);
			}

			if (vignetting) {
				col *= vignette();
			}

			gl_FragColor.rgb = col;
			gl_FragColor.a = 1.0;

			#include <tonemapping_fragment>
			#include <colorspace_fragment>
		}`

};

const BokehDepthShader = {

	name: 'BokehDepthShader',

	uniforms: {

		'mNear': { value: 1.0 },
		'mFar': { value: 1000.0 },

	},

	vertexShader: /* glsl */`

		varying float vViewZDepth;

		void main() {

			#include <begin_vertex>
			#include <project_vertex>

			vViewZDepth = - mvPosition.z;

		}`,

	fragmentShader: /* glsl */`

		uniform float mNear;
		uniform float mFar;

		varying float vViewZDepth;

		void main() {

			float color = 1.0 - smoothstep( mNear, mFar, vViewZDepth );
			gl_FragColor = vec4( vec3( color ), 1.0 );

		}`

};

export { BokehShader, BokehDepthShader };
