#version 330

uniform sampler2D refractionTex;
uniform sampler2D reflectionTex;
uniform sampler2D dudvMap;
uniform sampler2D normalMap;
uniform sampler2D depthMap;

uniform vec3 lightColor;

uniform float moveFactor;

in vec4 clipSpace;
in vec2 TexCoords0;
in vec3 toCameraVector;
in vec3 fromLightVector;

out vec4 FragColor;

const float waveStrength = 0.005;
const float shineDamper = 20.0;
const float reflectivity = 0.75;

void main()
{
	// Get Normalized Device Space (-1 to 1)
	vec2 ndc = clipSpace.xy / clipSpace.w;
	// Make it 0 to 1
	ndc = ndc / 2.0 + 0.5;

	vec2 refractUV = vec2(ndc.x, ndc.y);
	vec2 reflectUV = vec2(ndc.x, -ndc.y);

	float near = 0.1;
	float far = 1000.0;
	float depth = texture2D(depthMap, refractUV).r;
	float floorDistance = 2.0 * near * far / (far + near - (2.0 * depth - 1.0) * (far - near));
	if (depth >= 1.0)
		discard;

	depth = gl_FragCoord.z;
	float waterDistance = 2.0 * near * far / (far + near - (2.0 * depth - 1.0) * (far - near));
	float waterDepth = floorDistance - waterDistance;



	vec2 distortedUV = texture2D(dudvMap, vec2(TexCoords0.x + moveFactor, TexCoords0.y)).rg * waveStrength;
	distortedUV = TexCoords0 + vec2(distortedUV.x, distortedUV.y + moveFactor);
	vec2 totalDistortion = (texture2D(dudvMap, distortedUV).rg * 2.0 - 1.0) * waveStrength * clamp(waterDepth * 8.0, 0.0, 1.0);

	//vec2 distortion1 = (texture2D(dudvMap, vec2(TexCoords0.x + moveFactor, TexCoords0.y)).rg * 2.0 - 1.0) * waveStrength;
	//vec2 distortion2 = (texture2D(dudvMap, vec2(-TexCoords0.x + moveFactor, TexCoords0.y + moveFactor)).rg * 2.0 - 1.0) * waveStrength;
	//vec2 totalDistortion = distortion1 + distortion2;

	refractUV += totalDistortion;
	refractUV = clamp(refractUV, 0.001, 0.999);

	reflectUV += totalDistortion;
	reflectUV.x = clamp(reflectUV.x, 0.001, 0.999);
	reflectUV.y = clamp(reflectUV.y, -0.999, -0.001);

	vec4 refractColor = texture2D(refractionTex, refractUV);
	vec4 reflectColor = texture2D(reflectionTex, reflectUV);

	vec4 normalMapColor = texture2D(normalMap, distortedUV);
	vec3 normal = vec3(normalMapColor.r * 2.0 - 1.0, normalMapColor.b * 3.0, normalMapColor.g * 2.0 - 1.0);
	normal = normalize(normal);

	vec3 viewVector = normalize(toCameraVector);
	float refractiveFactor = dot(viewVector, normal); //vec3(0.0, 1.0, 0.0));
	// Program works without this line, but it makes it more reflective at angles
	refractiveFactor = clamp(pow(refractiveFactor, 2.0), 0.0, 1.0);

	vec3 reflectedLight = reflect(normalize(fromLightVector), normal);
	float specular = max(dot(reflectedLight, viewVector), 0.0);
	specular = pow(specular, shineDamper);
	vec3 specularHighlights = lightColor * specular * reflectivity * clamp(waterDepth * 8.0, 0.0, 1.0);;

    FragColor = mix(reflectColor, refractColor, refractiveFactor);
	FragColor = mix(FragColor, vec4(0.0, 0.1, 0.25, 1.0), 0.2) + vec4(specularHighlights, 0.0);
	FragColor.a = clamp(waterDepth * 16.0, 0.0, 1.0);
	FragColor.r = waterDepth;
}