#pragma once

#include <string>

inline static constexpr auto ROUNDED_SHADER_FUNC = [](const std::string colorVarName) -> std::string {
    return R"#(

    // branchless baby!
    highp vec2 pixCoord = vec2(gl_FragCoord);
    pixCoord -= topLeft + fullSize * 0.5;
    pixCoord *= vec2(lessThan(pixCoord, vec2(0.0))) * -2.0 + 1.0;
    pixCoord -= fullSize * 0.5 - radius;

    if (pixCoord.x + pixCoord.y > radius) {

	    float dist = length(pixCoord);

	    if (dist > radius)
	        discard;

	    if (primitiveMultisample == 1 && dist > radius - 1.0) {
	        float distances = 0.0;
	        distances += float(length(pixCoord + vec2(0.25, 0.25)) < radius);
	        distances += float(length(pixCoord + vec2(0.75, 0.25)) < radius);
	        distances += float(length(pixCoord + vec2(0.25, 0.75)) < radius);
	        distances += float(length(pixCoord + vec2(0.75, 0.75)) < radius);

	        if (distances == 0.0)
		        discard;

	        distances /= 4.0;

	        )#" +
        colorVarName + R"#( = )#" + colorVarName + R"#( * distances;
        }

    }
)#";
};

inline const std::string QUADVERTSRC = R"#(
uniform mat3 proj;
uniform vec4 color;
attribute vec2 pos;
attribute vec2 texcoord;
varying vec4 v_color;
varying vec2 v_texcoord;

void main() {
    gl_Position = vec4(proj * vec3(pos, 1.0), 1.0);
    v_color = color;
    v_texcoord = texcoord;
})#";

inline const std::string QUADFRAGSRC = R"#(
precision mediump float;
varying vec4 v_color;

uniform vec2 topLeft;
uniform vec2 fullSize;
uniform float radius;

uniform int primitiveMultisample;

void main() {

    vec4 pixColor = v_color;

    if (radius > 0.0) {
	)#" +
    ROUNDED_SHADER_FUNC("pixColor") + R"#(
    }

    gl_FragColor = pixColor;
})#";

inline const std::string TEXVERTSRC = R"#(
uniform mat3 proj;
attribute vec2 pos;
attribute vec2 texcoord;
varying vec2 v_texcoord;

void main() {
    gl_Position = vec4(proj * vec3(pos, 1.0), 1.0);
    v_texcoord = texcoord;
})#";

inline const std::string TEXFRAGSRCRGBA = R"#(
precision mediump float;
varying vec2 v_texcoord; // is in 0-1
uniform sampler2D tex;
uniform float alpha;

uniform vec2 topLeft;
uniform vec2 fullSize;
uniform float radius;

uniform int discardOpaque;

uniform int applyTint;
uniform vec3 tint;

uniform int primitiveMultisample;

void main() {

    vec4 pixColor = texture2D(tex, v_texcoord);

    if (discardOpaque == 1 && pixColor[3] * alpha == 1.0)
	discard;


    if (applyTint == 1) {
	pixColor[0] = pixColor[0] * tint[0];
	pixColor[1] = pixColor[1] * tint[1];
	pixColor[2] = pixColor[2] * tint[2];
    }

    )#" +
    ROUNDED_SHADER_FUNC("pixColor") + R"#(

    gl_FragColor = pixColor * alpha;
})#";

inline const std::string TEXFRAGSRCRGBX = R"#(
precision mediump float;
varying vec2 v_texcoord;
uniform sampler2D tex;
uniform float alpha;

uniform vec2 topLeft;
uniform vec2 fullSize;
uniform float radius;

uniform int discardOpaque;

uniform int applyTint;
uniform vec3 tint;

uniform int primitiveMultisample;

void main() {

    if (discardOpaque == 1 && alpha == 1.0)
	discard;

    vec4 pixColor = vec4(texture2D(tex, v_texcoord).rgb, 1.0);

    if (applyTint == 1) {
	pixColor[0] = pixColor[0] * tint[0];
	pixColor[1] = pixColor[1] * tint[1];
	pixColor[2] = pixColor[2] * tint[2];
    }

    )#" +
    ROUNDED_SHADER_FUNC("pixColor") + R"#(

    gl_FragColor = pixColor * alpha;
})#";

inline const std::string FRAGBLUR1 = R"#(
#version 100
precision mediump float;
varying mediump vec2 v_texcoord; // is in 0-1
uniform sampler2D tex;

uniform float radius;
uniform vec2 halfpixel;

void main() {
    vec2 uv = v_texcoord * 2.0;

    vec4 sum = texture2D(tex, uv) * 4.0;
    sum += texture2D(tex, uv - halfpixel.xy * radius);
    sum += texture2D(tex, uv + halfpixel.xy * radius);
    sum += texture2D(tex, uv + vec2(halfpixel.x, -halfpixel.y) * radius);
    sum += texture2D(tex, uv - vec2(halfpixel.x, -halfpixel.y) * radius);

    gl_FragColor = sum / 8.0;
}
)#";

inline const std::string FRAGBLUR2 = R"#(
#version 100
precision mediump float;
varying mediump vec2 v_texcoord; // is in 0-1
uniform sampler2D tex;

uniform float radius;
uniform vec2 halfpixel;

void main() {
    vec2 uv = v_texcoord / 2.0;

    vec4 sum = texture2D(tex, uv + vec2(-halfpixel.x * 2.0, 0.0) * radius);

    sum += texture2D(tex, uv + vec2(-halfpixel.x, halfpixel.y) * radius) * 2.0;
    sum += texture2D(tex, uv + vec2(0.0, halfpixel.y * 2.0) * radius);
    sum += texture2D(tex, uv + vec2(halfpixel.x, halfpixel.y) * radius) * 2.0;
    sum += texture2D(tex, uv + vec2(halfpixel.x * 2.0, 0.0) * radius);
    sum += texture2D(tex, uv + vec2(halfpixel.x, -halfpixel.y) * radius) * 2.0;
    sum += texture2D(tex, uv + vec2(0.0, -halfpixel.y * 2.0) * radius);
    sum += texture2D(tex, uv + vec2(-halfpixel.x, -halfpixel.y) * radius) * 2.0;

    gl_FragColor = sum / 12.0;
}
)#";

inline const std::string TEXFRAGSRCEXT = R"#(
#extension GL_OES_EGL_image_external : require

precision mediump float;
varying vec2 v_texcoord;
uniform samplerExternalOES texture0;
uniform float alpha;

uniform vec2 topLeft;
uniform vec2 fullSize;
uniform float radius;

uniform int discardOpaque;

uniform int applyTint;
uniform vec3 tint;

uniform int primitiveMultisample;

void main() {

    vec4 pixColor = texture2D(texture0, v_texcoord);

    if (discardOpaque == 1 && pixColor[3] * alpha == 1.0)
	discard;

    if (applyTint == 1) {
	pixColor[0] = pixColor[0] * tint[0];
	pixColor[1] = pixColor[1] * tint[1];
	pixColor[2] = pixColor[2] * tint[2];
    }

    )#" +
    ROUNDED_SHADER_FUNC("pixColor") + R"#(

    gl_FragColor = pixColor * alpha;
}
)#";