#if !defined(WIN32) && !defined(_WIN32) && !defined(__WIN32)
#error Systems other than Windows are not supported.
#endif

/* libraries */

#include <windows.h>
#include <signal.h>

#include <shellapi.h>
#pragma comment(lib, "Shell32")
#include <shlwapi.h>
#pragma comment(lib, "Shlwapi.lib")

#include <stdio.h>

/* convenience macros */

#define err(code, string) do { fprintf(stderr, "%s: %s: %s\n", string, strerror(errno)); exit(code); } while (0)
#define die(...) do { fprintf(stderr, __VA_ARGS__); system("pause"); exit(1); } while (0)
#define bool int
#define true 1
#define false 0
#define USAGE "usage: %s [/c argument-string] URL\n", argv[0]

/* constants */

#define MAX_PATH 260
#define SR_ERR_NOASSOC (HINSTANCE)31

/* global variables */

char out[MAX_PATH]; /* temporary playlist file path */

/* handle break signal (Ctrl-Break) */

void sigbreak(int sig) {
  /* open playlist at break signal */
  if (ShellExecute(NULL, "open", out, NULL, NULL, 5) <= (HINSTANCE)32)
    die("failed to open %s\n", out);
  exit(0);
}

/* main interface */

int main(int argc, char *argv[]) {
  bool new, title;
  char *cmd, *extra, temp[MAX_PATH], *url;
  const char *fmt;
  FILE *f, *p;
  HINSTANCE r;
  int c, i, linecount;
  ULONGLONG last;
  
  signal(SIGBREAK, sigbreak);
  
  /* construct temporary playlist file path */
  
  if (GetTempPath(1 + MAX_PATH, temp) > 0 && strlen(temp) + 1 + 16 <= MAX_PATH) {
    strcpy(out, temp);
    if (temp[strlen(temp)-1] != '\\') strcat(out, "\\");
  }
  strcat(out, "watch.tmp.mpcpl");

  /* parse command-line flags and set default parameters */
  
  if (argc == 1) goto open; /* open previous link */
  
  if (argv[1][0] == '/') {
    if (argv[1][1] != 'c' || argc != 4) die(USAGE);
    extra = argv[2];
    url = argv[3];
  } else {
    if (argc != 2) die(USAGE);
    extra = "-f \"bestvideo[height<=1200],bestaudio/best\"";
    url = argv[1];
  }

  /* support watch: urls */

  if (strncmp(url, "watch:", 6) == 0)
    url += 6;

  /* support cloudtube urls */

  if (strncmp(url, "https://cadence.moe/cloudtube/video/", 36) == 0) {
    url += 36 - 28;
    memcpy(url, "https://youtube.com/watch?v=", 28);
  } else if (strncmp(url, "https://cadence.moe/cloudtube/", 30) == 0) {
    url += 30 - 20;
    memcpy(url, "https://youtube.com/", 20);
  }

  /* validate url format */
  
  for (i = 0; i < strlen(url); i++)
    if (url[i] == '"') die("URL cannot contain quotes (\")\n");
  
  /* start youtube-dl */
  
  fmt = "youtube-dl -eg --youtube-skip-dash-manifest %s \"%s\"";
  cmd = malloc(0 + (strlen(fmt) + strlen(url) + strlen(extra)) * sizeof(char));
  if (cmd == NULL) err(1, "malloc");
  if (sprintf(cmd, fmt, extra, url) < 0) err(1, "sprintf");
  
  p = _popen(cmd, "r");
  if (p == NULL) err(1, "popen");
  
  /* open temporary playlist file */
  
  f = fopen(out, "w");
  if (f == NULL) err(1, "fopen");
  
  /* read/write stream urls (from youtube-dl, to temporary playlist file) */
  
  linecount = 0;
  new = true;
  title = false;
  last = GetTickCount();
  
  c = fgetc(p);
  if (c == EOF) goto end;
  fprintf(f, "MPCPLAYLIST\n");
  goto loop;

  /* In the output from youtube-dl, each line contains a video or audio stream
   * belonging to a specific video. The only way to tell which streams belong
   * to the same video is to count the time between the output of each line. If
   * there is a pause between two lines, then the second one belongs to a new
   * video. */
  
  while ((c = fgetc(p)) != EOF) {
loop:
    if (new) {
      new = false;
      if (GetTickCount() - last > 20) { /* new video */
        title = true;
        linecount++;
        fprintf(stderr, "Retrieving video #%d\n", linecount);
        fprintf(f, "%d,type,0\n", linecount);
        fprintf(f, "%d,label,", linecount);
      } else
        fprintf(f, "%d,filename,", linecount);
    }
    fputc(c, f);
    if (c == '\n') {
      last = GetTickCount();
      new = true;
    }
  }

  /* check status of youtube-dl command */
  
end:
  if (i = _pclose(p)) /* if unsuccessful */
    if (i != -1073741510) /* and it wasn't due to Ctrl-Break (handled above) */
      die("youtube-dl exited with %d\n", i);
  
  /* open playlist */

open:
  if (ShellExecute(NULL, "open", out, NULL, NULL, 5) <= (HINSTANCE)32)
    die("failed to open %s\n", out);
  return 0;
}