/***************************************************************************************
 *
 * histogram.cc is part of SimpleSkyCam.
 *
 *****************************************************************************************/

#include "simpleskycam.h"
#include "histogram.h"
#include "gui.h"
#include "configuration.h"
#include "video.h"


GtkWidget *histogram_da = NULL;
GdkPixbuf *histogram_pixbuf = NULL;
int *hist_minmax = NULL;    // 2* hist_width min, max, min , max.....
int hist_width = 0;

extern GtkBuilder *_builder_;			// work around for threads


#define S_X(_x_) (((_x_) * clientw / pixbufw))
#define S_Y(_y_) (((_y_) * clienth / pixbufh))
void cb_histogramda_draw(GtkWidget *area, cairo_t *cr, int w, int h, gpointer data) {
	int clientw, clienth, pixbufw, pixbufh;
	GdkRGBA color;

	if (histogram_da == NULL) // should only be called once
		histogram_da = GTK_WIDGET(gtk_builder_get_object (GTK_BUILDER(_builder_), "histogram-da"));

	//
	// create or resize pixbuf if needed
	clienth = gtk_widget_get_allocated_height(histogram_da);
	clientw = gtk_widget_get_allocated_width(histogram_da);
	if (histogram_pixbuf == NULL) {
		histogram_pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, false, 8, clientw, clienth);
		memset (gdk_pixbuf_get_pixels(histogram_pixbuf), 0, 3 * gdk_pixbuf_get_height(histogram_pixbuf) * gdk_pixbuf_get_width(histogram_pixbuf));
	}

	pixbufh = gdk_pixbuf_get_height(histogram_pixbuf);
	pixbufw = gdk_pixbuf_get_width(histogram_pixbuf);
	if (pixbufw != clientw || pixbufh != clienth) {
		g_object_unref(histogram_pixbuf);
		histogram_pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, false, 8, clientw, clienth);
		memset (gdk_pixbuf_get_pixels(histogram_pixbuf), 0, 3 * gdk_pixbuf_get_height(histogram_pixbuf) * gdk_pixbuf_get_width(histogram_pixbuf));
	}

	//
	// put the drawing area on the screen
    gdk_cairo_set_source_pixbuf(cr, histogram_pixbuf, 0, 0);
    cairo_paint(cr);
    cairo_fill (cr);

	//
	// draw cross
	color.blue = 1.0;
	color.red = 0.0;
	color.green = 1.0;
	color.alpha = 1.0;
	gdk_cairo_set_source_rgba(cr, &color);

	cairo_move_to(cr, 0, 0);
	cairo_line_to(cr, pixbufw, pixbufh);
	cairo_move_to(cr, pixbufw, 0);
	cairo_line_to(cr, 0, pixbufh);

	cairo_stroke(cr);

	//
	// draw basic histogram
	if (hist_minmax != NULL) {
		//
		// draw cross
		color.blue = 0.75;
		color.red = 0.75;
		color.green = 0.75;
		color.alpha = 0.8;
		gdk_cairo_set_source_rgba(cr, &color);

		int x, i;			// position in histogram
		int px, py1, py2;	// screen pos x and line from to

		for (i = 0, x = 0; x < hist_width; x++) {

			px = (pixbufw * x) / hist_width;
			py1 = (pixbufh * hist_minmax[i++]) / 255;
			py2 = (pixbufh * hist_minmax[i++]) / 255;

			cairo_move_to(cr, px, py1);
			cairo_line_to(cr, px, py2);

			cairo_stroke(cr);
		}
	}

    // draw some text
    for (int i = 0; i < 5; i++) {
    	int dx, dy;

    	switch (i) {
    	case 0:
        	cairo_set_source_rgb(cr, 1.0, 1.0, 1.0);
        	dx = -1;
        	dy = 0;
    		break;
    	case 1:
        	dx = +1;
        	dy = 0;
    		break;
    	case 2:
        	dx = 0;
        	dy = -1;
    		break;
    	case 3:
        	dx = 0;
        	dy = +1;
    		break;
    	case 4:
        	cairo_set_source_rgb(cr, 0.1, 0.1, 0.1);
        	dx = 0;
        	dy = 0;
    		break;
    	}

    	cairo_select_font_face (cr, "sans-serif", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_BOLD);
    	cairo_set_font_size (cr, 12);
    	cairo_move_to (cr, 10+dx, 15+dy);
    	cairo_show_text(cr, "Test");
    	cairo_stroke(cr);
    }
};


/*
 * test function
 */
void histogram_update(VideoFrame *vf) {
	int i, x, y, min, max, v;

	if (vf == NULL) return;
	if (vf->w <= 0 ) return;

	if (hist_minmax == NULL ) {
		hist_minmax = (int*) malloc (2 * sizeof(int) * vf->w);
		hist_width = vf->w;
	}
	if (hist_width != vf->w) {
		free (hist_minmax);
		hist_minmax = (int*) malloc (2 * sizeof(int) * vf->w);
		hist_width = vf->w;
	}

	for (i = 0, x = 0; x < vf->w; x++) {
		for (y = 0; y < vf->h; y++) {
			v = (vf->data[3*y*vf->w+x + 0] +
				 vf->data[3*y*vf->w+x + 1] +
				 vf->data[3*y*vf->w+x + 2]) / 3;
			if (y == 0) {
				min = v;
				max = v;
			}

			if (v < min) min = v;
			if (v > max) max = v;
		}
		hist_minmax[i++] = min;
		hist_minmax[i++] = max;
	}

	if (histogram_da)
		gdk_window_invalidate_rect(gtk_widget_get_window(histogram_da), NULL, true);
};