#include <math.h>

#include <time.h>

#include <string.h>

#include <stdlib.h>

#include <helianthus.h>

#include "chunk.h"

#define COUNT 100

double t;

double x, y;

double vx = 10, vy = 0;

int rootSeed;

Chunk chunks[COUNT];

void initChunks() {

  srand(time(NULL));

  rootSeed = rand();

  Chunk *c = &chunks[0];

  chunkGenerate(c, rootSeed, NULL, -COUNT/2);

  for(int i = 1; i < COUNT; ++i, ++c)

    chunkGenerate(c+1, rootSeed, c, 1);

}

void prepareChunks(double x) {

  Chunk *first = chunks, *last = first + COUNT - 1;

  int i0 = (int)floor(x/CHUNK_WIDTH) - COUNT/2;

  int offset = i0 - chunks[0].index;

  if (offset < 0) {

    Chunk *next = last, *prev = first;

    if (offset > -COUNT) {

      memmove(first - offset, first, sizeof(*chunks)*(COUNT + offset));

      prev = first - offset;

      next = prev - 1;

      offset = 1;

    }

    while(next >= first)

      { chunkGenerate(next, rootSeed, prev, offset); prev = next--; offset = -1; }

  } else

  if (offset > 0) {

    Chunk *next = first, *prev = last;

    if (offset < COUNT) {

      memmove(first, first + offset, sizeof(*chunks)*(COUNT - offset));

      prev = last - offset;

      next = prev + 1;

      offset = 1;

    } else {

      offset -= COUNT - 1;

    }

    while(next <= last)

      { chunkGenerate(next, rootSeed, prev, offset); prev = next++; offset = 1; }

  }

}

void drawChunks(double x, double range, double t) {

  range += 5*2;

  int i0 = (int)floor((x - 0.5*range)/CHUNK_WIDTH) - chunks->index;

  int i1 = (int)floor((x + 0.5*range)/CHUNK_WIDTH) - chunks->index + 1;

  if (i0 < 0) i0 = 0;

  if (i1 > COUNT) i1 = COUNT;

  for(int i = i0; i < i1; ++i) chunkDraw(&chunks[i], t, FLAG_GROUND);

  //for(int i = i0; i < i1; ++i) chunkDraw(&chunks[i], t, FLAG_LEAVES);

  for(int i = i0; i < i1; ++i) chunkDraw(&chunks[i], t, FLAG_BRANCHES);

}

double groundLevel(double x) {

  int i = (int)floor(x/CHUNK_WIDTH) - chunks->index;

  if (i < 0) return chunks->y;

  if (i > COUNT-1) return chunks[COUNT-1].y + chunks[COUNT-1].dy;

  return chunkGroundLevel(&chunks[i], x);

}

void init() {

  initChunks();

}

void draw() {

  double dt = windowGetFrameTime();

  t += dt;

  int w = windowGetWidth();

  int h = windowGetHeight();

  double range = w;

  double gy = groundLevel(x);

  vy = 0.5*(gy - y + 20);

  x += dt*vx;

  y += dt*vy;

  if (keyWentDown("space")) initChunks();

  if (keyWentDown("right")) x += 10;

  if (keyWentDown("left")) x -= 10;

  if (keyWentDown("up")) y += 10;

  if (keyWentDown("down")) y -= 10;

  saveState();

  translate(0.5*w, 0.5*h);

  zoom(10);

  scale(1, -1);

  translate(-x, -y);

  range /= 10;

  prepareChunks(x);

  drawChunks(x, range, t);

  restoreState();

}

int main() {

  windowSetVariableFrameRate();

  windowSetResizable(TRUE);

  windowSetInit(&init);

  windowSetDraw(&draw);

  windowRun();

  return 0;

}