/***

    Olive - Non-Linear Video Editor
    Copyright (C) 2019  Olive Team

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

***/

#include "math.h"

#include <QtMath>
#include <QVector>

#include "debug.h"

int lerp(int a, int b, double t) {
  return qRound(((1.0 - t) * a) + (t * b));
}

float float_lerp(float a, float b, float t) {
  return ((1.0F - t) * a) + (t * b);
}

double double_lerp(double a, double b, double t) {
  return ((1.0 - t) * a) + (t * b);
}

double quad_from_t(double a, double b, double c, double t) {
  return qPow(1.0 - t, 2)*a + 2*(1.0 - t)*t*b + qPow(t, 2)*c;
}

double quad_t_from_x(double x, double a, double b, double c) {
  return (a - b + qSqrt(a*x + c*x - 2*b*x + qPow(b, 2) - a*c))/(a - 2*b + c);
  // alt: return (a - b - qSqrt(a*x + c*x - 2*b*x + qPow(b, 2) - a*c))/(a - 2*b + c);
}

double cubic_from_t(double a, double b, double c, double d, double t) {
  return qPow(1.0 - t, 3)*a + 3*qPow(1.0 - t, 2)*t*b + 3*(1.0 - t)*qPow(t, 2)*c + qPow(t, 3)*d;
}

double cubic_t_from_x(double x_target, double a, double b, double c, double d) {
  double tolerance = 0.0001;

  double lower = 0.0;
  double upper = 1.0;

  double percent = 0.5;
  double x = cubic_from_t(a, b, c, d, percent);

  while (qAbs(x_target - x) > tolerance) {
    if (x_target > x) {
      lower = percent;
    } else {
      upper = percent;
    }

    percent = (upper + lower) / 2.0;
    x = cubic_from_t(a, b, c, d, percent);
  }

  return percent;
}

double amplitude_to_db(double amplitude) {
  return (20.0*(qLn(amplitude)/qLn(10.0)));
}

double db_to_amplitude(double db) {
  return qPow(M_E, (db*qLn(10.0))/20.0);
}

QRect fit_size_into_rect(const QRect &r, int width, int height)
{
  // Get aspect ratio of object we're fitting
  double inner_ar = double(width) / double(height);

  // Get aspect ratio of rectangle
  double rect_ar = double(r.width()) / double(r.height());

  if (rect_ar > inner_ar) {
    // The rect is wider than the object, so we'll be limiting by height and scaling by width
    int new_width = qRound(r.height() * inner_ar);
    return QRect(r.x() + (r.width() / 2 - new_width / 2), r.y(), new_width, r.height());
  } else {
    // The rect is taller than the object, so we'll be limiting by width and scaling by height
    int new_height = qRound(r.width() / inner_ar);
    return QRect(r.x(), r.y() + (r.height() / 2 - new_height / 2), r.width(), new_height);
  }
}