#version 330

// Input vertex attributes (from vertex shader)
in vec2 fragTexCoord;
in vec4 fragColor;

// Input uniform values
uniform sampler2D texture0;
uniform vec4 colDiffuse;

uniform float u_time;
uniform float u_glitchIntensity;
uniform vec2 u_resolution;

// Output fragment color
out vec4 finalColor;

void main()
{
    vec2 uv = fragTexCoord;

    // 1. Digital Glitch / Chromatic Aberration
    float glitch = clamp(u_glitchIntensity, 0.0, 1.0);
    if (glitch > 0.001)
    {
        // Horizontal line slice displacement
        float slice = step(0.65, sin(uv.y * 35.0 + u_time * 25.0));
        float sliceOffset = (slice * 2.0 - 1.0) * 0.018 * glitch;
        uv.x += sliceOffset;

        // Chromatic RGB separation
        float split = 0.012 * glitch;
        float r = texture(texture0, vec2(uv.x + split, uv.y)).r;
        float g = texture(texture0, uv).g;
        float b = texture(texture0, vec2(uv.x - split, uv.y)).b;
        finalColor = vec4(r, g, b, 1.0);
    }
    else
    {
        finalColor = texture(texture0, uv);
    }

    // 2. Neon Bloom / Emissive Halo
    vec2 texel = 1.0 / u_resolution;
    vec3 bloom = vec3(0.0);
    float bloomWeight = 0.0;

    // 9-tap bright-pass sample
    vec2 offsets[8] = vec2[](
        vec2(-2.0,  0.0), vec2( 2.0,  0.0),
        vec2( 0.0, -2.0), vec2( 0.0,  2.0),
        vec2(-1.5, -1.5), vec2( 1.5, -1.5),
        vec2(-1.5,  1.5), vec2( 1.5,  1.5)
    );

    for (int i = 0; i < 8; ++i)
    {
        vec3 col = texture(texture0, uv + offsets[i] * texel * 1.8).rgb;
        float brightness = dot(col, vec3(0.2126, 0.7152, 0.0722));
        if (brightness > 0.55)
        {
            bloom += (col - 0.45) * 1.4;
            bloomWeight += 1.0;
        }
    }

    if (bloomWeight > 0.0)
    {
        bloom /= 8.0;
        finalColor.rgb += bloom * 0.75;
    }

    // 3. Vignette (Smooth cinematic edge darkening)
    float d = distance(uv, vec2(0.5, 0.5));
    float vignette = smoothstep(0.82, 0.38, d);
    finalColor.rgb *= mix(0.58, 1.0, vignette);

    // 4. Subtle Cyber Scanlines
    float scanline = sin(uv.y * u_resolution.y * 1.8) * 0.035;
    finalColor.rgb -= scanline;

    finalColor.a = 1.0;
}