/**
 * 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 MIN_PADDING 20         // Minimum padding in pixels
#define MAX_PADDING_PERCENT 0.04f  // Maximum 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

// Glass label positioning constants (adjustable parameters)
#define LABEL_OFFSET_X 12     // Horizontal offset from glass point (pixels)
#define LABEL_OFFSET_Y -8     // Vertical offset from glass point (pixels)
#define LABEL_SIZE_SCALE 1.4f // Scale factor for glass name labels

// Tight clustering parameters
#define MAX_CLUSTER_SIZE 8    // Maximum glasses per cluster
#define DEFAULT_TIGHT_CLUSTER_ND_THRESHOLD 0.0005f // Default nd difference threshold
#define DEFAULT_TIGHT_CLUSTER_VD_THRESHOLD 0.15f   // Default vd difference threshold

// Loose clustering parameters (zoom-dependent)
#define DEFAULT_LOOSE_CLUSTER_ND_THRESHOLD 0.3f  // Default nd base threshold
#define DEFAULT_LOOSE_CLUSTER_VD_THRESHOLD 0.55f    // Default vd base threshold
#define DEFAULT_LOOSE_CLUSTER_ND_FRACTION 4.9f   // Default nd fraction of visible range
#define DEFAULT_LOOSE_CLUSTER_VD_FRACTION 0.9f   // Default vd fraction of visible range

// Global tight cluster thresholds (adjustable parameters)
extern f32 g_tight_cluster_nd_threshold;
extern f32 g_tight_cluster_vd_threshold;

// Global loose cluster parameters (adjustable parameters)
extern f32 g_loose_cluster_nd_threshold;  // Base threshold
extern f32 g_loose_cluster_vd_threshold;  // Base threshold  
extern f32 g_loose_cluster_nd_fraction;   // Zoom scaling fraction
extern f32 g_loose_cluster_vd_fraction;   // Zoom scaling fraction

// Tight cluster structure
typedef struct {
    i32 glassIndices[MAX_CLUSTER_SIZE]; // Indices of glasses in this cluster
    i32 count;                          // Number of glasses in cluster
    i32 representativeIndex;            // Index of glass with shortest name
    f32 avgAbbeNumber;                  // Average position for reference
    f32 avgRefractiveIndex;
} TightCluster;

// Loose cluster structure (zoom-dependent)
typedef struct {
    i32 glassIndices[MAX_CLUSTER_SIZE]; // Indices of glasses in this cluster
    i32 count;                          // Number of glasses in cluster
    i32 representativeIndex;            // Index of glass with shortest name
    f32 avgAbbeNumber;                  // Average position for reference
    f32 avgRefractiveIndex;
} LooseCluster;


// 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)
    i32 selectedCluster;    // Index of selected tight cluster (-1 if none)
    
    // Tight cluster data (per catalog)
    TightCluster* tightClusters;  // Array of tight clusters for current catalog
    i32 tightClusterCount;        // Number of tight clusters
    
    // Loose cluster data (per catalog, zoom-dependent)
    LooseCluster* looseClusters;  // Array of loose clusters for current catalog
    i32 looseClusterCount;        // Number of loose clusters
    
    // Label recalculation tracking
    f32 lastZoomLevel;      // Last zoom level for which labels were calculated
    i32 lastWindowWidth;    // Last window width for labels
    i32 lastWindowHeight;   // Last window height for labels
    f32 lastOffsetX;        // Last X offset for labels
    f32 lastOffsetY;        // Last Y offset for labels
} ViewState;

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

// Refresh view state data range when catalog changes
void refresh_view_data_range(ViewState* view);

// Helper function to calculate adaptive padding
static inline i32 get_adaptive_padding(const ViewState* view) {
    i32 padding = (i32)(view->windowWidth * MAX_PADDING_PERCENT);
    return padding > MIN_PADDING ? padding : MIN_PADDING;
}

// 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 = get_adaptive_padding(view);
    
    // 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 = get_adaptive_padding(view);
    
    // 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);

// Tight clustering functions
void create_tight_clusters(ViewState* view);
void free_tight_clusters(ViewState* view);
i32 find_tight_cluster_for_glass(i32 glassIndex, const ViewState* view);

// Loose clustering functions (zoom-dependent)
void create_loose_clusters(ViewState* view);
void free_loose_clusters(ViewState* view);
i32 find_loose_cluster_for_glass(i32 glassIndex, const ViewState* view);

// Combined clustering logic
b32 should_show_glass_label(i32 glassIndex, const ViewState* view);


#endif /* GLAMAC_VIEW_H */