/**
 * glamac_view.h - header file from glamac_view.c.
 */
#ifndef GLAMAC_VIEW_H
#define GLAMAC_VIEW_H

#include <SDL3/SDL.h>
#include "glamacdef.h"

// Constants for view
#define PADDING_PERCENT 0.08f  // Padding as percentage of window size
#define PAN_STEP 0.05f        // Step size for keyboard panning
#define ZOOM_FACTOR 1.2f      // Zoom factor for zoom operations
#define MIN_ZOOM 0.5f         // Minimum zoom level
#define MAX_ZOOM 10.0f        // Maximum zoom level

// State for zooming and panning
typedef struct {
    f32 zoomLevel;
    f32 offsetX;
    f32 offsetY;
    i32 windowWidth;
    i32 windowHeight;
    f32 minAbbe;
    f32 maxAbbe;
    f32 minRI;
    f32 maxRI;
    b32 showHelp;           // Flag to show/hide help window
    b32 gKeyPressed;        // Flag to track if 'g' was pressed
    u32 gKeyTime;           // Time when 'g' was pressed for sequence timing
    i32 selectedGlass;      // Index of selected glass (-1 if none)
} ViewState;

// Initialize a view state with default values
void init_view_state(ViewState* view, i32 windowWidth, i32 windowHeight);

// Convert glass data to screen coordinates with zoom and offset
static inline void data_to_screen_coords(f32 abbeNumber, f32 refractiveIndex, 
                              const ViewState* view, i32 *x, i32 *y) {
    const i32 padding = (i32)(view->windowWidth * PADDING_PERCENT);
    
    // Apply zoom and offset transformation
    // FLIPPED: Use 1.0f - normalized to flip the Abbe number axis
    f32 normalizedX = 1.0f - (abbeNumber - view->minAbbe) / (view->maxAbbe - view->minAbbe);
    f32 normalizedY = (refractiveIndex - view->minRI) / (view->maxRI - view->minRI);
    
    // Transform with zoom and offset
    normalizedX = (normalizedX - 0.5f) * view->zoomLevel + 0.5f + view->offsetX;
    normalizedY = (normalizedY - 0.5f) * view->zoomLevel + 0.5f + view->offsetY;
    
    // Convert to screen coordinates
    *x = padding + (i32)(normalizedX * (view->windowWidth - 2 * padding));
    *y = view->windowHeight - padding - (i32)(normalizedY * (view->windowHeight - 2 * padding));
}

// Convert screen coordinates to data values
static inline void screen_to_data_coords(i32 x, i32 y, const ViewState* view, 
                              f32 *abbeNumber, f32 *refractiveIndex) {
    const i32 padding = (i32)(view->windowWidth * PADDING_PERCENT);
    
    // Convert to normalized coordinates
    f32 normalizedX = (f32)(x - padding) / (view->windowWidth - 2 * padding);
    f32 normalizedY = (f32)(view->windowHeight - y - padding) / (view->windowHeight - 2 * padding);
    
    // Reverse transform with zoom and offset
    normalizedX = (normalizedX - view->offsetX - 0.5f) / view->zoomLevel + 0.5f;
    normalizedY = (normalizedY - view->offsetY - 0.5f) / view->zoomLevel + 0.5f;
    
    // Convert to data values - FLIPPED axis logic for Abbe
    *abbeNumber = view->maxAbbe - normalizedX * (view->maxAbbe - view->minAbbe);
    *refractiveIndex = view->minRI + normalizedY * (view->maxRI - view->minRI);
}

// Find the nearest glass to a given screen position
i32 find_nearest_glass(i32 x, i32 y, const ViewState* view, f32 maxDistance);

// Calculate visible data range based on current view
void get_visible_data_range(const ViewState* view, f32 *visibleMinAbbe, f32 *visibleMaxAbbe, 
                       f32 *visibleMinRI, f32 *visibleMaxRI);

// Handle mouse wheel zoom
void handle_mouse_wheel_zoom(i32 wheelY, i32 mouseX, i32 mouseY, ViewState* view);

// Toggle fullscreen
void toggle_fullscreen(SDL_Window* window);

// Reset view to default
void reset_view(ViewState* view);

#endif /* GLAMAC_VIEW_H */