/* Utilities.
 *
 * Author: Daniel Krebs <github@daniel-krebs.net>
 * Author: Steffen Vogel <post@steffenvogel.de>
 * SPDX-FileCopyrightText: 2014-2023 Institute for Automation of Complex Power Systems, RWTH Aachen University
 * SPDX-License-Identifier: Apache-2.0
 */

#include <iostream>
#include <string>
#include <vector>

#include <cctype>
#include <cmath>
#include <cstdarg>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <fcntl.h>
#include <pthread.h>
#include <unistd.h>

#include <jansson.h>
#include <openssl/bio.h>
#include <openssl/buffer.h>
#include <openssl/evp.h>

#include <villas/colors.hpp>
#include <villas/config.hpp>
#include <villas/exceptions.hpp>
#include <villas/log.hpp>
#include <villas/utils.hpp>

static pthread_t main_thread;

namespace villas {
namespace utils {

std::vector<std::string> tokenize(std::string s, const std::string &delimiter) {
  std::vector<std::string> tokens;

  size_t lastPos = 0;
  size_t curentPos;

  while ((curentPos = s.find(delimiter, lastPos)) != std::string::npos) {
    const size_t tokenLength = curentPos - lastPos;
    tokens.push_back(s.substr(lastPos, tokenLength));

    // Advance in string
    lastPos = curentPos + delimiter.length();
  }

  // Check if there's a last token behind the last delimiter.
  if (lastPos != s.length()) {
    const size_t lastTokenLength = s.length() - lastPos;
    tokens.push_back(s.substr(lastPos, lastTokenLength));
  }

  return tokens;
}

ssize_t readRandom(char *buf, size_t len) {
  int fd;
  ssize_t bytes = -1;

  fd = open("/dev/urandom", O_RDONLY);
  if (fd < 0)
    return -1;

  while (len) {
    bytes = read(fd, buf, len);
    if (bytes < 0)
      break;

    len -= bytes;
    buf += bytes;
  }

  close(fd);

  return bytes;
}

// Setup exit handler
int signalsInit(void (*cb)(int signal, siginfo_t *sinfo, void *ctx),
                std::list<int> cbSignals, std::list<int> ignoreSignals) {
  int ret;

  Logger logger = logging.get("signals");

  logger->info("Initialize subsystem");

  struct sigaction sa_cb;
  sa_cb.sa_flags = SA_SIGINFO | SA_NODEFER;
  sa_cb.sa_sigaction = cb;

  struct sigaction sa_ign;
  sa_ign.sa_flags = 0;
  sa_ign.sa_handler = SIG_IGN;

  main_thread = pthread_self();

  sigemptyset(&sa_cb.sa_mask);
  sigemptyset(&sa_ign.sa_mask);

  cbSignals.insert(cbSignals.begin(),
                   {SIGINT, SIGTERM, SIGUSR1, SIGUSR2, SIGALRM});
  cbSignals.sort();
  cbSignals.unique();

  for (auto signal : cbSignals) {
    ret = sigaction(signal, &sa_cb, nullptr);
    if (ret)
      return ret;
  }

  for (auto signal : ignoreSignals) {
    ret = sigaction(signal, &sa_ign, nullptr);
    if (ret)
      return ret;
  }

  return 0;
}

char *decolor(char *str) {
  char *p, *q;
  bool inseq = false;

  for (p = q = str; *p; p++) {
    switch (*p) {
    case 0x1b:
      if (*(++p) == '[') {
        inseq = true;
        continue;
      }
      break;

    case 'm':
      if (inseq) {
        inseq = false;
        continue;
      }
      break;
    }

    if (!inseq) {
      *q = *p;
      q++;
    }
  }

  *q = '\0';

  return str;
}

void killme(int sig) {
  // Send only to main thread in case the ID was initilized by signalsInit()
  if (main_thread)
    pthread_kill(main_thread, sig);
  else
    kill(0, sig);
}

double boxMuller(float m, float s) {
  double x1, x2, y1;
  static double y2;
  static int use_last = 0;

  if (use_last) { // Use value from previous call
    y1 = y2;
    use_last = 0;
  } else {
    double w;
    do {
      x1 = 2.0 * randf() - 1.0;
      x2 = 2.0 * randf() - 1.0;
      w = x1 * x1 + x2 * x2;
    } while (w >= 1.0);

    w = sqrt(-2.0 * log(w) / w);
    y1 = x1 * w;
    y2 = x2 * w;
    use_last = 1;
  }

  return m + y1 * s;
}

double randf() { return (double)random() / RAND_MAX; }

char *vstrcatf(char **dest, const char *fmt, va_list ap) {
  char *tmp;
  int n = *dest ? strlen(*dest) : 0;
  int i = vasprintf(&tmp, fmt, ap);

  *dest = (char *)(realloc(*dest, n + i + 1));
  if (*dest != nullptr)
    strncpy(*dest + n, tmp, i + 1);

  free(tmp);

  return *dest;
}

char *strcatf(char **dest, const char *fmt, ...) {
  va_list ap;
  va_start(ap, fmt);
  vstrcatf(dest, fmt, ap);
  va_end(ap);

  return *dest;
}

char *strf(const char *fmt, ...) {
  char *buf = nullptr;

  va_list ap;
  va_start(ap, fmt);
  vstrcatf(&buf, fmt, ap);
  va_end(ap);

  return buf;
}

char *vstrf(const char *fmt, va_list va) {
  char *buf = nullptr;

  vstrcatf(&buf, fmt, va);

  return buf;
}

void *memdup(const void *src, size_t bytes) {
  void *dst = new char[bytes];
  if (!dst)
    throw MemoryAllocationError();

  memcpy(dst, src, bytes);

  return dst;
}

pid_t spawn(const char *name, char *const argv[]) {
  pid_t pid;

  pid = fork();
  switch (pid) {
  case -1:
    return -1;
  case 0:
    return execvp(name, (char *const *)argv);
  }

  return pid;
}

size_t strlenp(const char *str) {
  size_t sz = 0;

  for (const char *d = str; *d; d++) {
    const unsigned char *c = (const unsigned char *)d;

    if (isprint(*c))
      sz++;
    else if (c[0] == '\b')
      sz--;
    else if (c[0] == '\t')
      sz += 4; // Tab width == 4
    // CSI sequence
    else if (c[0] == '\e' && c[1] == '[') {
      c += 2;
      while (*c && *c != 'm')
        c++;
    }
    // UTF-8
    else if (c[0] >= 0xc2 && c[0] <= 0xdf) {
      sz++;
      c += 1;
    } else if (c[0] >= 0xe0 && c[0] <= 0xef) {
      sz++;
      c += 2;
    } else if (c[0] >= 0xf0 && c[0] <= 0xf4) {
      sz++;
      c += 3;
    }

    d = (const char *)c;
  }

  return sz;
}

int log2i(long long x) {
  if (x == 0)
    return 1;

  return sizeof(x) * 8 - __builtin_clzll(x) - 1;
}

int sha1sum(FILE *f, unsigned char *sha1) {
  int ret;
  char buf[512];
  ssize_t bytes;
  long seek;

  seek = ftell(f);
  fseek(f, 0, SEEK_SET);

  EVP_MD_CTX *c = EVP_MD_CTX_new();

  ret = EVP_DigestInit(c, EVP_sha1());
  if (!ret)
    return -1;

  bytes = fread(buf, 1, 512, f);
  while (bytes > 0) {
    EVP_DigestUpdate(c, buf, bytes);
    bytes = fread(buf, 1, 512, f);
  }

  EVP_DigestFinal(c, sha1, nullptr);

  fseek(f, seek, SEEK_SET);

  EVP_MD_CTX_free(c);

  return 0;
}

bool isDocker() { return access("/.dockerenv", F_OK) != -1; }

bool isKubernetes() {
  return access("/var/run/secrets/kubernetes.io", F_OK) != -1 ||
         getenv("KUBERNETES_SERVICE_HOST") != nullptr;
}

bool isContainer() { return isDocker() || isKubernetes(); }

bool isPrivileged() {
  // TODO: a cleaner way would be to use libcap here and check for the
  //       SYS_ADMIN capability.
  auto *f = fopen(PROCFS_PATH "/sys/vm/nr_hugepages", "w");
  if (!f)
    return false;

  fclose(f);

  return true;
}

} // namespace utils
} // namespace villas
