#version 440 core

#include <constants.glsl>

#define LIGHTING_TYPE (LIGHTING_TYPE_TRANSMISSION | LIGHTING_TYPE_REFLECTION)

#define LIGHTING_REFLECTION_KIND LIGHTING_REFLECTION_KIND_SPECULAR

#if (FLUID_MODE == FLUID_MODE_LOW)
#define LIGHTING_TRANSPORT_MODE LIGHTING_TRANSPORT_MODE_IMPORTANCE
#elif (FLUID_MODE >= FLUID_MODE_MEDIUM)
#define LIGHTING_TRANSPORT_MODE LIGHTING_TRANSPORT_MODE_RADIANCE
#endif

#define LIGHTING_DISTRIBUTION_SCHEME LIGHTING_DISTRIBUTION_SCHEME_MICROFACET

#define LIGHTING_DISTRIBUTION LIGHTING_DISTRIBUTION_BECKMANN

#include <globals.glsl>
// Note: The sampler uniform is declared here because it differs for MSAA
#include <anti-aliasing.glsl>
#include <srgb.glsl>
#include <cloud.glsl>
#include <random.glsl>
#include <lod.glsl>

layout(set = 1, binding = 0)
uniform texture2D t_src_color;
layout(set = 1, binding = 1)
uniform sampler s_src_color;

layout(set = 1, binding = 2)
uniform texture2D t_src_depth;
layout(set = 1, binding = 3)
uniform sampler s_src_depth;

layout(location = 0) in vec2 uv;

layout (std140, set = 1, binding = 4)
uniform u_locals {
    mat4 proj_mat_inv;
    mat4 view_mat_inv;
};

#ifdef BLOOM_FACTOR
layout(set = 1, binding = 5)
uniform texture2D t_src_bloom;
#ifdef EXPERIMENTAL_GRADIENTSOBEL
layout(set = 1, binding = 6)
uniform utexture2D t_src_mat;
#endif
#else
#ifdef EXPERIMENTAL_GRADIENTSOBEL
layout(set = 1, binding = 5)
uniform utexture2D t_src_mat;
#endif
#endif

layout(location = 0) out vec4 tgt_color;

vec3 rgb2hsv(vec3 c) {
    vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0);
    vec4 p = mix(vec4(c.bg, K.wz), vec4(c.gb, K.xy), step(c.b, c.g));
    vec4 q = mix(vec4(p.xyw, c.r), vec4(c.r, p.yzx), step(p.x, c.r));

    float d = q.x - min(q.w, q.y);
    float e = 1.0e-10;
    return vec3(abs(q.z + (q.w - q.y) / (6.0 * d + e)), d / (q.x + e), q.x);
}

vec3 hsv2rgb(vec3 c) {
    vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
    vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
    return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
}

vec3 _illuminate(float max_light, vec3 view_dir, /*vec3 max_light, */vec3 emitted, vec3 reflected) {
    const float NIGHT_EXPOSURE = 10.0;
    const float DUSK_EXPOSURE = 2.0;//0.8;
    const float DAY_EXPOSURE = 1.0;//0.7;

    const float DAY_SATURATION = 1.0;
    const float DUSK_SATURATION = 0.6;
    const float NIGHT_SATURATION = 0.1;

    const float gamma = /*0.5*//*1.*0*/1.0;//1.0;
    /* float light = length(emitted + reflected);
    float color = srgb_to_linear(emitted + reflected);
    float avg_col = (color.r + color.g + color.b) / 3.0;
    return ((color - avg_col) * light + reflected * avg_col) * (emitted + reflected); */
    // float max_intensity = vec3(1.0);
    vec3 color = emitted + reflected;
    float lum = rel_luminance(color);
    // float lum_sky = lum - max_light;

    // vec3 sun_dir = get_sun_dir(time_of_day.x);
    // vec3 moon_dir = get_moon_dir(time_of_day.x);
    // float sky_light = rel_luminance(
    //         get_sun_color(sun_dir) * get_sun_brightness(sun_dir) * SUN_COLOR_FACTOR +
    //         get_moon_color(moon_dir) * get_moon_brightness(moon_dir));
    float sky_light = lum;

    // Tone mapped value.
    // vec3 T = /*color*//*lum*/color;//normalize(color) * lum / (1.0 + lum);
    // float alpha = 0.5;//2.0;
    // float alpha = mix(
    //     mix(
    //         DUSK_EXPOSURE,
    //         NIGHT_EXPOSURE,
    //         max(sun_dir.z, 0)
    //     ),
    //     DAY_EXPOSURE,
    //     max(-sun_dir.z, 0)
    // );
    float alpha = 1.0;//log(1.0 - lum) / lum;
    // vec3 now_light = moon_dir.z < 0 ? moon_dir : sun_dir;
    // float cos_view_light = dot(-now_light, view_dir);
    // alpha *= exp(1.0 - cos_view_light);
    // sky_light *= 1.0 - log(1.0 + view_dir.z);
    float alph = sky_light > 0.0 && max_light > 0.0 ? mix(1.0 / log(/*1.0*//*1.0 + *//*lum_sky + */1.0 + max_light / (0.0 + sky_light)), 1.0, clamp(max_light - sky_light, 0.0, 1.0)) : 1.0;
    alpha = alpha * alph;// min(alph, 1.0);//((max_light > 0.0 && max_light > sky_light /* && sky_light > 0.0*/) ? /*1.0*/1.0 / log(/*1.0*//*1.0 + *//*lum_sky + */1.0 + max_light - (0.0 + sky_light)) : 1.0);
    // alpha = alpha * min(1.0, (max_light == 0.0 ? 1.0 : (1.0 + abs(lum_sky)) / /*(1.0 + max_light)*/max_light));

    vec3 col_adjusted = lum == 0.0 ? vec3(0.0) : color / lum;

    // float L = lum == 0.0 ? 0.0 : log(lum);


    // // float B = T;
    // // float B = L + log(alpha);
    // float B = lum;

    // float D = L - B;

    // float o = 0.0;//log(PERSISTENT_AMBIANCE);
    // float scale = /*-alpha*/-alpha;//1.0;

    // float B_ = (B - o) * scale;

    // // float T = lum;
    // float O = exp(B_ + D);

    float T = 1.0 - exp(-alpha * lum);//lum / (1.0 + lum);
    // float T = lum;

    // Heuristic desaturation
    // const float s = 0.8;
    float s = 1.0;
    // float s = mix(
    //     mix(
    //         DUSK_SATURATION,
    //         NIGHT_SATURATION,
    //         max(sun_dir.z, 0)
    //     ),
    //     DAY_SATURATION,
    //     max(-sun_dir.z, 0)
    // );
    // s = max(s, (max_light) / (1.0 + s));
    // s = max(s, max_light / (1.0 + max_light));
    // s = max_light / (1.0 + max_light);

    vec3 c = pow(col_adjusted, vec3(s)) * T;
    // vec3 c = col_adjusted * T;
    // vec3 c = sqrt(col_adjusted) * T;
    // vec3 c = /*col_adjusted * */col_adjusted * T;

    return c;
    // float sum_col = color.r + color.g + color.b;
    // return /*srgb_to_linear*/(/*0.5*//*0.125 * */vec3(pow(color.x, gamma), pow(color.y, gamma), pow(color.z, gamma)));
}

#ifdef EXPERIMENTAL_SOBEL
vec3 aa_sample(vec2 uv, vec2 off) {
    return aa_apply(t_src_color, s_src_color, t_src_depth, s_src_depth, uv * screen_res.xy + off, screen_res.xy).rgb;
}
#endif
#ifdef EXPERIMENTAL_GRADIENTSOBEL
vec3 aa_sample_grad(vec2 uv, vec2 off) {
    uvec2 mat_sz = textureSize(usampler2D(t_src_mat, s_src_depth), 0);
    uvec4 mat = texelFetch(usampler2D(t_src_mat, s_src_depth), clamp(ivec2(uv * mat_sz + off), ivec2(0), ivec2(mat_sz) - 1), 0);
    return vec3(mat.xyz) / 255.0;
}
#endif

#ifdef EXPERIMENTAL_COLORDITHERING
    float dither(ivec2 p, float level) {
        // Bayer dithering
        int dither[8][8] = {
            { 0, 32, 8, 40, 2, 34, 10, 42}, /* 8x8 Bayer ordered dithering */
            {48, 16, 56, 24, 50, 18, 58, 26}, /* pattern. Each input pixel */
            {12, 44, 4, 36, 14, 46, 6, 38}, /* is scaled to the 0..63 range */
            {60, 28, 52, 20, 62, 30, 54, 22}, /* before looking in this table */
            { 3, 35, 11, 43, 1, 33, 9, 41}, /* to determine the action. */
            {51, 19, 59, 27, 49, 17, 57, 25},
            {15, 47, 7, 39, 13, 45, 5, 37},
            {63, 31, 55, 23, 61, 29, 53, 21}
        };
        return step((dither[p.x % 8][p.y % 8]+1) * 0.016, level);
    }
#endif

void main() {
    #ifdef EXPERIMENTAL_BAREMINIMUM
        tgt_color = vec4(texture(sampler2D(t_src_color, s_src_color), uv).rgb, 1);
        return;
    #endif

    /* if (medium.x == 1u) {
        uv = clamp(uv + vec2(sin(uv.y * 16.0 + tick.x), sin(uv.x * 24.0 + tick.x)) * 0.005, 0, 1);
    } */

    vec2 c_uv = vec2(0.5);//uv;//vec2(0.5);//uv;
    vec2 delta = /*sqrt*//*sqrt(2.0) / 2.0*//*sqrt(2.0) / 2.0*//*0.5 - */min(uv, 1.0 - uv);//min(uv * (1.0 - uv), 0.25) * 2.0;
    // delta = /*sqrt(2.0) / 2.0 - */sqrt(vec2(dot(delta, delta)));
    // delta = 0.5 - vec2(min(delta.x, delta.y));
    delta = vec2(0.25);//vec2(dot(/*0.5 - */delta, /*0.5 - */delta));//vec2(min(delta.x, delta.y));//sqrt(2.0) * (0.5 - vec2(min(delta.x, delta.y)));
    // delta = vec2(sqrt(dot(delta, delta)));
    // vec2 delta = /*sqrt*//*sqrt(2.0) / 2.0*//*sqrt(2.0) / 2.0*/1.0 - vec2(sqrt(dot(uv, 1.0 - uv)));//min(uv * (1.0 - uv), 0.25) * 2.0;
    // float delta = /*sqrt*//*sqrt(2.0) / 2.0*//*sqrt(2.0) / 2.0*/1.0 - (dot(uv - 0.5, uv - 0.5));//0.01;//25;
    // vec2 delta = /*sqrt*//*sqrt(2.0) / 2.0*//*sqrt(2.0) / 2.0*/sqrt(uv * (1.0 - uv));//min(uv * (1.0 - uv), 0.25) * 2.0;

    // float bright_color0 = rel_luminance(texelFetch/*texture*/(src_color, ivec2(clamp(c_uv + vec2(0.0, 0.0), 0.0, 1.0) * screen_res.xy/* / 50*/)/* * 50*/, 0).rgb);
    // float bright_color1 = rel_luminance(texelFetch/*texture*/(src_color, ivec2(clamp(c_uv + vec2(delta.x, delta.y), 0.0, 1.0) * screen_res.xy/* / 50*/)/* * 50*/, 0).rgb);
    // float bright_color2 = rel_luminance(texelFetch/*texture*/(src_color, ivec2(clamp(c_uv + vec2(delta.x, -delta.y), 0.0, 1.0) * screen_res.xy/* / 50*/)/* * 50*/, 0).rgb);
    // float bright_color3 = rel_luminance(texelFetch/*texture*/(src_color, ivec2(clamp(c_uv + vec2(-delta.x, delta.y), 0.0, 1.0) * screen_res.xy/* / 50*/)/* * 50*/, 0).rgb);
    // float bright_color4 = rel_luminance(texelFetch/*texture*/(src_color, ivec2(clamp(c_uv + vec2(-delta.x, -delta.y), 0.0, 1.0) * screen_res.xy/* / 50*/)/* * 50*/, 0).rgb);

    // float bright_color0 = rel_luminance(texture(src_color, /*ivec2*/(clamp(c_uv + vec2(0.0, 0.0), 0.0, 1.0)/* * screen_res.xy*//* / 50*/)/* * 50*/, 0).rgb);
    // float bright_color1 = rel_luminance(texture(src_color, /*ivec2*/(clamp(c_uv + vec2(delta, delta), 0.0, 1.0)/* * screen_res.xy*//* / 50*/)/* * 50*/, 0).rgb);
    // float bright_color2 = rel_luminance(texture(src_color, /*ivec2*/(clamp(c_uv + vec2(delta, -delta), 0.0, 1.0)/* * screen_res.xy*//* / 50*/)/* * 50*/, 0).rgb);
    // float bright_color3 = rel_luminance(texture(src_color, /*ivec2*/(clamp(c_uv + vec2(-delta, delta), 0.0, 1.0)/* * screen_res.xy*//* / 50*/)/* * 50*/, 0).rgb);
    // float bright_color4 = rel_luminance(texture(src_color, /*ivec2*/(clamp(c_uv + vec2(-delta, -delta), 0.0, 1.0)/* * screen_res.xy*//* / 50*/)/* * 50*/, 0).rgb);

    // float bright_color = max(bright_color0, max(bright_color1, max(bright_color2, max(bright_color3, bright_color4))));// / 2.0;// / 5.0;

    // float bright_color = (bright_color0 + bright_color1 + bright_color2 + bright_color3 + bright_color4) / 5.0;

    // TODO: this causes flickering when the camera is moving into and out of solid blocks, resolve before uncommenting
    // if (medium.x == 2u) {
    //     tgt_color = vec4(0, 0.005, 0.01, 1) * (1 + hash_fast(uvec3(vec3(uv * screen_res.xy / 32.0, 0))));
    //     return;
    // }

    vec2 sample_uv = uv;
    #ifdef EXPERIMENTAL_UNDERWARPER
        if (medium.x == MEDIUM_WATER) {
            float x = tick_loop(2.0 * PI, 3.0, uv.y * 60);
            float y = tick_loop(2.0 * PI, 3.0, uv.x * 60);
            sample_uv += sin(vec2(x, y)) * 0.003;
        }
    #endif

    vec4 aa_color = aa_apply(t_src_color, s_src_color, t_src_depth, s_src_depth, sample_uv * screen_res.xy, screen_res.xy);

    #ifdef EXPERIMENTAL_SOBEL
        vec3 s[8];
        s[0] = aa_sample(uv, vec2(-1,  1));
        s[1] = aa_sample(uv, vec2( 0,  1));
        s[2] = aa_sample(uv, vec2( 1,  1));
        s[3] = aa_sample(uv, vec2(-1,  0));
        s[4] = aa_sample(uv, vec2( 1,  0));
        s[5] = aa_sample(uv, vec2(-1, -1));
        s[6] = aa_sample(uv, vec2( 0, -1));
        s[7] = aa_sample(uv, vec2( 1, -1));
        vec3 gx = s[0] + s[3] * 2.0 + s[5] - s[2] - s[4] * 2 - s[7];
        vec3 gy = s[0] + s[1] * 2.0 + s[2] - s[5] - s[6] * 2 - s[7];
        float mag = length(gx) + length(gy);
        aa_color.rgb = mix(vec3(0.9), aa_color.rgb * 0.8, clamp(1.0 - mag * 0.3, 0.0, 1.0));
    #endif
    #ifdef EXPERIMENTAL_GRADIENTSOBEL
        vec3 s2[8];
        s2[0] = aa_sample_grad(uv, vec2(-1,  1));
        s2[1] = aa_sample_grad(uv, vec2( 0,  1));
        s2[2] = aa_sample_grad(uv, vec2( 1,  1));
        s2[3] = aa_sample_grad(uv, vec2(-1,  0));
        s2[4] = aa_sample_grad(uv, vec2( 1,  0));
        s2[5] = aa_sample_grad(uv, vec2(-1, -1));
        s2[6] = aa_sample_grad(uv, vec2( 0, -1));
        s2[7] = aa_sample_grad(uv, vec2( 1, -1));
        vec3 gx2 = s2[0] + s2[3] * 2.0 + s2[5] - s2[2] - s2[4] * 2 - s2[7];
        vec3 gy2 = s2[0] + s2[1] * 2.0 + s2[2] - s2[5] - s2[6] * 2 - s2[7];
        float mag2 = length(gx2) + length(gy2);
        aa_color.rgb = mix(vec3(0.0), aa_color.rgb * 0.8, clamp(1.0 - mag2 * 0.3, 0.0, 1.0));
    #endif

    // Bloom
    #ifdef BLOOM_FACTOR
        vec4 bloom = textureLod(sampler2D(t_src_bloom, s_src_color), sample_uv, 0);
        #if (BLOOM_UNIFORM_BLUR == false)
            // divide by 4.0 to account for adding blurred layers together
            bloom /= 4.0;
        #endif
        aa_color = mix(aa_color, bloom, BLOOM_FACTOR);
    #endif

    // Tonemapping
    float exposure_offset = 1.0;
    // Adding an in-code offset to gamma and exposure let us have more precise control over the game's look
    #ifdef EXPERIMENTAL_CINEMATIC
        float gamma_offset = 0.5;
    #else
        float gamma_offset = 0.3;
    #endif
    aa_color.rgb = vec3(1.0) - exp(-aa_color.rgb * (gamma_exposure.y + exposure_offset));
    // gamma correction
    aa_color.rgb = pow(aa_color.rgb, vec3(gamma_exposure.x + gamma_offset));

    /*
    // Apply clouds to `aa_color`
    #if (CLOUD_MODE != CLOUD_MODE_NONE)
        vec3 wpos = wpos_at(uv);
        float dist = distance(wpos, cam_pos.xyz);
        vec3 dir = (wpos - cam_pos.xyz) / dist;

        aa_color.rgb = get_cloud_color(aa_color.rgb, dir, cam_pos.xyz, dist, 1.0);
    #endif
    */

    // aa_color.rgb = (wpos + focus_off.xyz) / vec3(32768, 32768, /*view_distance.w*/2048);
    // aa_color.rgb = mod((wpos + focus_off.xyz), vec3(32768, 32768, view_distance.w)) / vec3(32768, 32768, view_distance.w);// / vec3(32768, 32768, view_distance.w);
    // aa_color.rgb = mod((wpos + focus_off.xyz), vec3(32, 32, 16)) / vec3(32, 32, 16);// / vec3(32768, 32768, view_distance.w);
    // aa_color.rgb = focus_off.xyz / vec3(32768, 32768, view_distance.w);

    /* aa_color.rgb = wpos / 10000.0; */

    /* aa_color.rgb = vec3((texture(src_depth, uv).x - 0.99) * 100.0); */

    /* aa_color.rgb = vec3((dist - 100000) / 300000.0, 1, 1); */

    /* vec3 scatter_color = get_sun_color() * get_sun_brightness() + get_moon_color() * get_moon_brightness(); */

    /* aa_color.rgb += cloud_color.rgb * scatter_color;//mix(aa_color, vec4(cloud_color.rgb * scatter_color, 1), cloud_color.a); */

    // aa_color.rgb = illuminate(1.0 - 1.0 / (1.0 + bright_color), normalize(cam_pos.xyz - focus_pos.xyz), /*vec3 max_light, */vec3(0.0), aa_color.rgb);

    //vec4 hsva_color = vec4(rgb2hsv(fxaa_color.rgb), fxaa_color.a);
    //hsva_color.y *= 1.45;
    //hsva_color.z *= 0.85;
    //hsva_color.z = 1.0 - 1.0 / (1.0 * hsva_color.z + 1.0);
    //vec4 final_color = vec4(hsv2rgb(hsva_color.rgb), hsva_color.a);

    vec4 final_color = aa_color;

#if (FLUID_MODE == FLUID_MODE_LOW)
    if (medium.x == MEDIUM_WATER) {
        final_color *= vec4(0.2, 0.2, 0.8, 1.0);
    }
#endif

#ifndef EXPERIMENTAL_NODITHER
    // Add a small amount of very cheap dithering noise to remove banding from gradients
    // TODO: Consider dithering each color channel independently.
    // TODO: Consider varying dither over time.
    // TODO: Instead of 255, detect the colour resolution of the color attachment
    float noise = hash_two(uvec2(uv * screen_res.xy));
    #ifndef EXPERIMENTAL_NONSRGBDITHER
        #ifndef EXPERIMENTAL_TRIANGLENOISEDITHER
            noise = noise - 0.5;
        #else
            // TODO: there is something special we have to do to remove bias
            // on the bounds when using triangle distribution
            noise = 2.0 * norm2tri(noise) - 1.0;
        #endif
        final_color.rgb = srgb_to_linear(linear_to_srgb(final_color.rgb) + noise / 255.0);
    #else
        // NOTE: GPU will clamp value
        final_color.rgb = final_color.rgb - noise / 255.0;
    #endif
#endif

    #ifdef EXPERIMENTAL_NEWSPAPER
        float nz = hash_three(uvec3(uvec2(uv * screen_res.xy), tick.x * dot(fract(uv * 10) + 5, vec2(1)) * 0.2));
        nz = (nz > 0.5) ? (pow(nz * 2 - 1, 1.5) * 0.5 + 0.5) : (pow(nz * 2, 1/1.5) * 0.5);
        final_color.rgb = vec3(step(nz, length(final_color.rgb))) * vec3(1, 0.5, 0.3);
    #else
        #ifdef EXPERIMENTAL_COLORDITHERING
            float d = dither(ivec2(uv * screen_res.xy), sqrt(length(final_color.rgb) * 0.25));
            final_color.rgb = vec3(d) * sqrt(normalize(final_color.rgb));
        #endif
    #endif

    #ifdef EXPERIMENTAL_CINEMATIC
        final_color.rgb = hsv2rgb(rgb2hsv(final_color.rgb) * vec3(1, 1, 1.3) + vec3(-0.01, 0.05, 0));
    #endif

    tgt_color = vec4(final_color.rgb, 1);
}