#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <time.h>

#include <unistd.h>

#include "strdup/strdup.h"

#include "asprintf/asprintf.h"

#include "wildcardcmp/wildcardcmp.h"

#include "debug.h"

/**

 * Have we seeded `rand()`?

 */

static int seeded = 0;

/**

 * Log format.

 */

#define FMT "\x1B[3%dm%s\033[0m"

/**

 * ENV var delimiter.

 */

#define DELIMITER ","

/**

 * Check if the given `stream` is a TTY, and/or if

 * the environment variable `DEBUG_COLORS` has been

 * disabled.

 */

static int

use_colors(FILE *stream) {

  // only use color for a TTY

  int tty = isatty(fileno(stream));

  if (0 == tty) return 0;

  // check env

  char *colors = getenv("DEBUG_COLORS");

  if (!colors) return 1;

  // see: https://github.com/visionmedia/debug/blob/2.1.0/node.js#L49-L52

  if (0 == strcmp("0", colors)) return 0;

  if (0 == strncmp("no", colors, 2)) return 0;

  if (0 == strncmp("false", colors, 5)) return 0;

  if (0 == strncmp("disabled", colors, 8)) return 0;

  return 1;

}

int

debug_is_enabled(const char *name) {

  char *env = NULL;

  char *tmp = NULL;

  char *debugger = NULL;

  int enabled = 0;

  // get DEBUG env var

  if (!(env = getenv("DEBUG"))) return 0;

  if (!(tmp = strdup(env))) return 0;

  debugger = strtok(tmp, DELIMITER);

  while (debugger) {

    // support DEBUG=foo*

    if (1 == wildcardcmp(debugger, name)) {

      enabled = 1;

      break;

    }

    debugger = strtok(NULL, DELIMITER);

  }

  free(tmp);

  return enabled;

}

int

debug_init(debug_t *debugger, const char *name) {

  // seed, if necessary

  if (0 == seeded) {

    srand(clock());

    seeded = 1;

  }

  // random color

  debugger->color = 1 + (rand() % 6);

  // set enabled flag

  debugger->enabled = debug_is_enabled(name);

  // name, stream

  debugger->name = name;

  debugger->stream = stderr;

  return 0;

}

void

debug(debug_t *debugger, const char *fmt, ...) {

  // noop when disabled

  if (0 == debugger->enabled) return;

  char *pre = NULL;

  char *post = NULL;

  va_list args;

  va_start(args, fmt);

  if (use_colors(debugger->stream)) {

    // [color][name][/color]

    if (-1 == asprintf(&pre, FMT, debugger->color, debugger->name)) {

      va_end(args);

      return;

    }

  } else {

    // [name]

    if (!(pre = strdup(debugger->name))) {

      va_end(args);

      return;

    }

  }

  // format args

  if (-1 == vasprintf(&post, fmt, args)) {

    free(pre);

    va_end(args);

    return;

  }

  // print to stream

  fprintf(debugger->stream, " %s : %s\n", pre, post);

  // release memory

  free(pre);

  free(post);

}