//
// Copyright 2008 Johannes Hofmann <Johannes.Hofmann@gmx.de>
//
// This software may be used and distributed according to the terms
// of the GNU General Public License, incorporated herein by reference.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

#include <FL/Fl.H>
#include <FL/fl_draw.H>

#include "CurveEditor.H"

CurveEditor::CurveEditor(int my_x, int my_y, int my_w, int my_h) :
	Fl_Widget(my_x, my_y, my_w, my_h) {

	X = Y = NULL;
	marked_point = -1;
	cb = NULL;
	cb_data = NULL;
	n = 0;
	acc = gsl_interp_accel_alloc();
	spline = NULL;
}

void
CurveEditor::draw() {
	double step = 1.0 / w() / 2;

	fl_color(FL_BLACK);
	fl_rectf(x(), y(), w(), h());

	fl_color(FL_GRAY);
	fl_line_style(FL_DASH);
	fl_xyline(x(), y() + h() / 2, x() + w());
	fl_yxline(x() + w() / 2, y(), y() + h());

	if (n < 3)
		return;

	fl_push_clip(x(), y(), w(), h());
	fl_color(FL_WHITE);
	fl_line_style(FL_SOLID);
	fl_begin_line();
	for (double _x = 0.0; _x <= 1.0; _x = _x + step) {
		double _y = gsl_spline_eval(spline, _x, acc);

		fl_vertex(x() + _x * w(), y() + h() - h() * _y);
	}
	fl_end_line();

	for (int i = 0; i < n; i++)
		fl_rectf((int) rint(x() + w() * X[i] - 2),
			(int) rint(y() + h() - h() * Y[i] - 2), 4, 4);

	fl_pop_clip();
}

int
CurveEditor::handle(int event) {
	double mark_x = (double) (Fl::event_x() - x()) / w();
	double mark_y = 1.0 - (double) (Fl::event_y() - y()) / h();

	switch (event) {
		case FL_PUSH:    
			Fl::focus(this);
			if (Fl::event_button() == 1) {
				for (int i = 0; i < n; i++) {
					if (mark_x >= X[i] - 0.02 && mark_x <= X[i] + 0.02) {
						marked_point = i;
						move_point(i, mark_x, mark_y);
						redraw();
						return 1;
					}
				}

				marked_point = add_point(mark_x, mark_y);
			}
			return 1;
		case FL_DRAG:
			if (marked_point < 0)
				return 1;
			if (marked_point > 0 && mark_x <= X[marked_point - 1] ||
				marked_point < n - 1 && mark_x >= X[marked_point + 1]) {
				remove_point(marked_point);
				marked_point = -1;
				if (cb)
					cb(this, cb_data);
			} else
				move_point(marked_point, mark_x, mark_y);
			return 1;
		case FL_RELEASE:
			if (marked_point >= 0) {
				if (cb)
					cb(this, cb_data);
				marked_point = -1;
			}
			return 1;
		case FL_FOCUS:
			return 1;
		case FL_UNFOCUS:
			return 0;
        }
	return 0;
}

int
CurveEditor::add_point(double _x, double _y) {
	int i;

	if (_x < 0.0 || _x > 1.0 || _y < 0.0 || _y > 1.0)
		return -1;

	X = (double*) realloc(X, (n + 1) * sizeof(double));
	Y = (double*) realloc(Y, (n + 1) * sizeof(double));

	for (i = 0; i < n; i++) {
		if (_x == X[i])
			return -1;
		if (_x < X[i]) {
			memmove(&X[i + 1], &X[i], sizeof(double) * (n - i));
			memmove(&Y[i + 1], &Y[i], sizeof(double) * (n - i));
			break;
		}
	}

	X[i] = _x;
	Y[i] = _y;
	n++;
	init();

	return i;
}

void
CurveEditor::init() {
	if (n < 3)
		return;
	if (spline)
		gsl_spline_free(spline);
	spline = gsl_spline_alloc(gsl_interp_cspline, n);
	gsl_spline_init(spline, X, Y, n);
	redraw();
}

void
CurveEditor::move_point(int i, double _x, double _y) {
	if (i >= n ||
		(_x < 0.0 || _x > 1.0 || _y < 0.0 || _y > 1.0) ||
		(i < n - 1 && _x >= X[i + 1]) ||
		(i > 0 && _x <= X[i - 1]))
		return;

	X[i] = _x;
	Y[i] = _y;
	gsl_spline_init(spline, X, Y, n);
	redraw();
}

void
CurveEditor::remove_point(int i) {
 	if (i < 0 || i >= n)
		return;
	
	memmove(&X[i], &X[i + 1], sizeof(double) * (n - i));
	memmove(&Y[i], &Y[i + 1], sizeof(double) * (n - i));
	n--;
	init();
}

void
CurveEditor::get_point(int i, double *_x, double *_y) {
	if (i < 0 || i >= n)
		return;

	*_x = X[i];
	*_y = Y[i];
}

void CurveEditor::clear() {
	if (X)
		free(X);
	if (Y)
		free(Y);

	X = Y = NULL;
	n = 0;
}