#include <math.h>
#include <ncurses.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define DEFAULT_AMPLITUDE 1
#define DEFAULT_PERIOD .35
#define DEFAULT_DELAY_MULTIPLIER 150
#define BASE_DELAY 100

// Color count
#define NUM_COLORS 6

typedef unsigned short ushort;

ushort printwave(double amplitude, double period, short phase_shift,
                 ushort color_index) {

  double x;
  for (x = 0.0; x < (COLS + phase_shift); x += 1.0) {

    // Swap color
    color_index += 1;
    attron(COLOR_PAIR((color_index % NUM_COLORS) + 1));

    // Find Y
    double ratio = (2.0 * M_PI) / LINES;
    double y = sin(period * x * ratio);
    y *= amplitude;
    y += LINES / 2;

    // Print cell
    mvprintw((int)(y), (int)(x - phase_shift), " ");
  }

  return color_index;
}

int main(int argc, char *argv[]) {
  // Curses init
  WINDOW *screen = initscr();
  start_color();
  nodelay(screen, 1);
  cbreak();
  noecho();
  curs_set(0);
  keypad(screen, TRUE);

  // Color pairs
  init_pair(1, COLOR_RED, COLOR_BLACK);
  init_pair(2, COLOR_GREEN, COLOR_BLACK);
  init_pair(3, COLOR_YELLOW, COLOR_BLACK);
  init_pair(4, COLOR_BLUE, COLOR_BLACK);
  init_pair(5, COLOR_MAGENTA, COLOR_BLACK);
  init_pair(6, COLOR_CYAN, COLOR_BLACK);
  init_pair(7, COLOR_WHITE, COLOR_BLACK);
  attron(A_BOLD);
  attron(A_STANDOUT);

  // Wave attributes
  unsigned char delayx = DEFAULT_DELAY_MULTIPLIER;
  ushort color_index = 0;
  short phase_shift = 0;
  double amplitude = (LINES / 2) * DEFAULT_AMPLITUDE;
  double period = DEFAULT_PERIOD;

  while (1) {

    erase();

    color_index = printwave(amplitude, period, phase_shift, color_index);

    attron(COLOR_PAIR(7));
    mvprintw(0, 0, "PERIOD %.2f", period);
    mvprintw(1, 0, "AMP: %.2f", amplitude);
    mvprintw(2, 0, "PHASE: %d", phase_shift);
    mvprintw(3, 0, "DELAY: x%hu", delayx);

    refresh();

    switch (getch()) {
    case KEY_UP:
    case 'k':
      amplitude += 1.0;
      break;
    case KEY_DOWN:
    case 'j':
      amplitude -= 1.0;
      break;
    case KEY_LEFT:
    case 'h':
      period -= .05;
      break;
    case KEY_RIGHT:
    case 'l':
      period += .05;
      break;
    case ' ':
      phase_shift = 0.0;
      break;
    case '+':
      delayx += 1;
      break;
    case '-':
      delayx -= 1;
      break;
    case 'q':
      endwin();
      return 0;
    default:
      break;
    }

    usleep(BASE_DELAY * delayx);

    phase_shift += 1;

    if (phase_shift * period >= LINES)
      phase_shift = 0;
  }

  endwin();
  return 0;
}