using Raylib;
using static Raylib.Raylib;

public partial class Examples
{
    /*******************************************************************************************
    *
    *   raylib [textures] example - Image processing
    *
    *   NOTE: Images are loaded in CPU memory (RAM); textures are loaded in GPU memory (VRAM)
    *
    *   This example has been created using raylib 1.4 (www.raylib.com)
    *   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
    *
    *   Copyright (c) 2016 Ramon Santamaria (@raysan5)
    *
    ********************************************************************************************/
    
    
    
    public const #define NUM_PROCESSES    8

    typedef enum { 
        NONE = 0, 
        COLOR_GRAYSCALE, 
        COLOR_TINT, 
        COLOR_INVERT, 
        COLOR_CONTRAST, 
        COLOR_BRIGHTNESS, 
        FLIP_VERTICAL, 
        FLIP_HORIZONTAL 
    } ImageProcess;
    
    static const char *processText[] = {
        "NO PROCESSING",
        "COLOR GRAYSCALE",
        "COLOR TINT",
        "COLOR INVERT",
        "COLOR CONTRAST",
        "COLOR BRIGHTNESS",
        "FLIP VERTICAL",
        "FLIP HORIZONTAL"
    };
    
    public static void Main()
    {
        // Initialization
        //--------------------------------------------------------------------------------------
        int screenWidth = 800;
        int screenHeight = 450;
    
        InitWindow(screenWidth, screenHeight, "raylib [textures] example - image processing");
    
        // NOTE: Textures MUST be loaded after Window initialization (OpenGL context is required)
    
        Image image = LoadImage("resources/parrots.png");   // Loaded in CPU memory (RAM)
        ImageFormat(&image, UNCOMPRESSED_R8G8B8A8);         // Format image to RGBA 32bit (required for texture update) <-- ISSUE
        Texture2D texture = LoadTextureFromImage(image);    // Image converted to texture, GPU memory (VRAM)
    
        int currentProcess = NONE;
        bool textureReload = false;
    
        Rectangle[] selectRecs = new Rectangle[NUM_PROCESSES];
        
        for (int i = 0; i < NUM_PROCESSES; i++) selectRecs[i] = new Rectangle( 40, 50 + 32*i, 150, 30 );;
        
        SetTargetFPS(60);
        //---------------------------------------------------------------------------------------
    
        // Main game loop
        while (!WindowShouldClose())    // Detect window close button or ESC key
        {
            // Update
            //----------------------------------------------------------------------------------
            if (IsKeyPressed((int)Key.DOWN))
            {
                currentProcess++;
                if (currentProcess > 7) currentProcess = 0;
                textureReload = true;
            }
            else if (IsKeyPressed((int)Key.UP))
            {
                currentProcess--;
                if (currentProcess < 0) currentProcess = 7;
                textureReload = true;
            }
            
            if (textureReload)
            {
                UnloadImage(image);                         // Unload current image data
                image = LoadImage("resources/parrots.png"); // Re-load image data
    
                // NOTE: Image processing is a costly CPU process to be done every frame, 
                // If image processing is required in a frame-basis, it should be done 
                // with a texture and by shaders
                switch (currentProcess)
                {
                    case COLOR_GRAYSCALE: ImageColorGrayscale(&image); break;
                    case COLOR_TINT: ImageColorTint(&image, GREEN); break;
                    case COLOR_INVERT: ImageColorInvert(&image); break;
                    case COLOR_CONTRAST: ImageColorContrast(&image, -40); break;
                    case COLOR_BRIGHTNESS: ImageColorBrightness(&image, -80); break;
                    case FLIP_VERTICAL: ImageFlipVertical(&image); break;
                    case FLIP_HORIZONTAL: ImageFlipHorizontal(&image); break;
                    default: break;
                }
                
                Color *pixels = GetImageData(image);        // Get pixel data from image (RGBA 32bit)
                UpdateTexture(texture, pixels);             // Update texture with new image data
                free(pixels);                               // Unload pixels data from RAM
                
                textureReload = false;
            }
            //----------------------------------------------------------------------------------
    
            // Draw
            //----------------------------------------------------------------------------------
            BeginDrawing();
    
                ClearBackground(RAYWHITE);
                
                DrawText("IMAGE PROCESSING:", 40, 30, 10, DARKGRAY);
                
                // Draw rectangles
                for (int i = 0; i < NUM_PROCESSES; i++)
                {
                    DrawRectangleRec(selectRecs[i], (i == currentProcess) ? SKYBLUE : LIGHTGRAY);
                    DrawRectangleLines(selectRecs[i].x, selectRecs[i].y, selectRecs[i].width, selectRecs[i].height, (i == currentProcess) ? BLUE : GRAY);
                    DrawText(processText[i], selectRecs[i].x + selectRecs[i].width/2 - MeasureText(processText[i], 10)/2, selectRecs[i].y + 11, 10, (i == currentProcess) ? DARKBLUE : DARKGRAY);
                }
    
                DrawTexture(texture, screenWidth - texture.width - 60, screenHeight/2 - texture.height/2, WHITE);
                DrawRectangleLines(screenWidth - texture.width - 60, screenHeight/2 - texture.height/2, texture.width, texture.height, BLACK);
                
            EndDrawing();
            //----------------------------------------------------------------------------------
        }
    
        // De-Initialization
        //--------------------------------------------------------------------------------------
        UnloadTexture(texture);       // Unload texture from VRAM
        UnloadImage(image);           // Unload image from RAM
    
        CloseWindow();                // Close window and OpenGL context
        //--------------------------------------------------------------------------------------
    
        return 0;
    }    
}