#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static int evtdev = -1;
static int fbdev = -1;
static int screen_w = 0, screen_h = 0;

#include <NDL.h>
#include <sys/time.h>
uint32_t NDL_GetTicks() {
  struct timeval t;
  gettimeofday(&t, NULL);
  return t.tv_sec * 1000 + t.tv_usec / 1000;
}

int NDL_PollEvent(char *buf, int len) {
  FILE* fd = fopen("/dev/events", "r");
  if (fd == NULL) {
    printf("cannot open /dev/events");
    exit(-1);
  }
  size_t ret = fread(buf, 1, len, fd);
  // if (ret) printf("NDL_PollEvent read %d bytes is %s", ret, buf);
  fclose(fd);
  return ret;
}

static void _get_screen(int *w, int *h) {
  static int dev_w = -1, dev_h = -1, num = -1;

  FILE* fp = fopen("/proc/dispinfo", "r");
  if (fp == NULL) {
    printf("cannot open /proc/dispinfo");
    exit(-1);
  }
  
  char buf[64], name[32];
  const char* pos = buf;
  fread(buf, 1, sizeof(buf), fp);
  int life = 2;
  // FIXME this have a bug to phase the ` [KEY] : [VALUE] `
  while (sscanf(pos, "%s : %d\n", name, &num) == 2 && life--) {
    pos = strchr(pos, '\n');
    if (pos == NULL) break;
    if (strcmp(name, "WIDTH") == 0)  { dev_w = num; }
    if (strcmp(name, "HEIGHT") == 0) { dev_h = num; }
  }
  *w = dev_w;
  *h = dev_h;
  // printf("screen size: %d %d\n", dev_w, dev_h);
  fclose(fp);
}

void NDL_OpenCanvas(int *w, int *h) {
  if (getenv("NWM_APP")) {
    int fbctl = 4;
    fbdev = 5;
    screen_w = *w; screen_h = *h;
    char buf[64];
    int len = sprintf(buf, "%d %d", screen_w, screen_h);
    // let NWM resize the window and create the frame buffer
    write(fbctl, buf, len);
    while (1) {
      // 3 = evtdev
      int nread = read(3, buf, sizeof(buf) - 1);
      if (nread <= 0) continue;
      buf[nread] = '\0';
      if (strcmp(buf, "mmap ok") == 0) break;
    }
    close(fbctl);
  }

  int dev_w, dev_h;
  _get_screen(&dev_w, &dev_h);
  screen_w = (*w == 0 || *w > dev_w) ? dev_w : *w;
  screen_h = (*h == 0 || *h > dev_h) ? dev_h : *h;
  *w = screen_w;
  *h = screen_h;
  // printf("NDL_OpenCanvas: %d,%d, dev %d,%d\n", screen_w, screen_h, dev_w, dev_h);
}

void NDL_DrawRect(uint32_t *pixels, int x, int y, int w, int h) {
  FILE* fp = fopen("/dev/fb", "w");
  if (fp == NULL) {
    printf("cannot open /dev/fb");
    exit(-1);
  }

  int dev_w, dev_h;
  _get_screen(&dev_w, &dev_h);
  int _x = (dev_w - w) / 2;
  int _y = (dev_h - h) / 2;
  // printf("NDL_DrawRect: %d,%d, dev %d,%d, wh %d,%d, xy %d,%d\n", _x, _y, dev_w, dev_h, w, h, x, y);
  for (int i = 0; i < h; i ++) {
    // printf("log:%d,%d, dev %d,%d, wh %d,%d, xy %d,%d\n", _x, _y + i, dev_w, dev_h, w, h, x, y);
    fseek(fp, NDL_SCREEN_POS(_x, _y + i, dev_w, dev_h), SEEK_SET);
    fwrite(pixels + NDL_SCREEN_IDX(x, y + i, w, h), 4, w, fp);
  }
  fclose(fp);
}

void NDL_OpenAudio(int freq, int channels, int samples) {
  FILE* fp = fopen("/dev/sbctl", "w");
  if (fp == NULL) {
    printf("cannot open /dev/fb");
    exit(-1);
  }
  int arr[] = {
    freq, channels, samples
  };
  fwrite(arr, sizeof(int), 3, fp);
  fclose(fp);
}

void NDL_CloseAudio() {
  
}

int NDL_PlayAudio(void *buf, int len) {
  FILE* fp = fopen("/dev/sb", "w");
  if (fp == NULL) {
    printf("cannot open /dev/fb");
    exit(-1);
  }
  fwrite(buf, 1, len, fp);
  fclose(fp);
  return len;
}

int NDL_QueryAudio() {
  FILE* fp = fopen("/dev/sbctl", "r");
  if (fp == NULL) {
    printf("cannot open /dev/fb");
    exit(-1);
  }
  int ret;
  fread(&ret, sizeof(int), 1, fp);
  fclose(fp);
  return ret;
}

int NDL_Init(uint32_t flags) {
  if (getenv("NWM_APP")) {
    evtdev = 3;
  }
  return 0;
}

void NDL_Quit() {
}