/*
 * nghttp2 - HTTP/2 C Library
 *
 * Copyright (c) 2012 Tatsuhiro Tsujikawa
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
#ifndef UTIL_H
#define UTIL_H

#include "nghttp2_config.h"

#include <unistd.h>
#include <getopt.h>

#include <cmath>
#include <cstring>
#include <cassert>
#include <vector>
#include <string>
#include <algorithm>
#include <sstream>
#include <memory>
#include <chrono>

#include "http-parser/http_parser.h"

namespace nghttp2 {

// The additional HTTP/2 protocol ALPN protocol identifier we also
// supports for our applications.  This will be removed once HTTP/2
// specification is finalized.
#define NGHTTP2_H2_16_ALPN "\x5h2-16"
#define NGHTTP2_H2_16_ALPN_LEN (sizeof(NGHTTP2_H2_16_ALPN) - 1)
#define NGHTTP2_H2_16_ID "h2-16"
#define NGHTTP2_H2_16_ID_LEN (sizeof(NGHTTP2_H2_16_ID) - 1)

namespace util {

extern const char DEFAULT_STRIP_CHARSET[];

template <typename InputIterator>
std::pair<InputIterator, InputIterator>
stripIter(InputIterator first, InputIterator last,
          const char *chars = DEFAULT_STRIP_CHARSET) {
  for (; first != last && strchr(chars, *first) != 0; ++first)
    ;
  if (first == last) {
    return std::make_pair(first, last);
  }
  InputIterator left = last - 1;
  for (; left != first && strchr(chars, *left) != 0; --left)
    ;
  return std::make_pair(first, left + 1);
}

template <typename InputIterator, typename OutputIterator>
OutputIterator splitIter(InputIterator first, InputIterator last,
                         OutputIterator out, char delim, bool doStrip = false,
                         bool allowEmpty = false) {
  for (InputIterator i = first; i != last;) {
    InputIterator j = std::find(i, last, delim);
    std::pair<InputIterator, InputIterator> p(i, j);
    if (doStrip) {
      p = stripIter(i, j);
    }
    if (allowEmpty || p.first != p.second) {
      *out++ = p;
    }
    i = j;
    if (j != last) {
      ++i;
    }
  }
  if (allowEmpty && (first == last || *(last - 1) == delim)) {
    *out++ = std::make_pair(last, last);
  }
  return out;
}

template <typename InputIterator, typename OutputIterator>
OutputIterator split(InputIterator first, InputIterator last,
                     OutputIterator out, char delim, bool doStrip = false,
                     bool allowEmpty = false) {
  for (InputIterator i = first; i != last;) {
    InputIterator j = std::find(i, last, delim);
    std::pair<InputIterator, InputIterator> p(i, j);
    if (doStrip) {
      p = stripIter(i, j);
    }
    if (allowEmpty || p.first != p.second) {
      *out++ = std::string(p.first, p.second);
    }
    i = j;
    if (j != last) {
      ++i;
    }
  }
  if (allowEmpty && (first == last || *(last - 1) == delim)) {
    *out++ = std::string(last, last);
  }
  return out;
}

template <typename InputIterator, typename DelimiterType>
std::string strjoin(InputIterator first, InputIterator last,
                    const DelimiterType &delim) {
  std::string result;
  if (first == last) {
    return result;
  }
  InputIterator beforeLast = last - 1;
  for (; first != beforeLast; ++first) {
    result += *first;
    result += delim;
  }
  result += *beforeLast;
  return result;
}

template <typename InputIterator>
std::string joinPath(InputIterator first, InputIterator last) {
  std::vector<std::string> elements;
  for (; first != last; ++first) {
    if (*first == "..") {
      if (!elements.empty()) {
        elements.pop_back();
      }
    } else if (*first == ".") {
      // do nothing
    } else {
      elements.push_back(*first);
    }
  }
  return strjoin(elements.begin(), elements.end(), "/");
}

bool isAlpha(const char c);

bool isDigit(const char c);

bool isHexDigit(const char c);

bool inRFC3986UnreservedChars(const char c);

// Returns true if |c| is in token (HTTP-p1, Section 3.2.6)
bool in_token(char c);

bool in_attr_char(char c);

std::string percentEncode(const unsigned char *target, size_t len);

std::string percentEncode(const std::string &target);

std::string percentDecode(std::string::const_iterator first,
                          std::string::const_iterator last);

// Percent encode |target| if character is not in token or '%'.
std::string percent_encode_token(const std::string &target);

// Returns quotedString version of |target|.  Currently, this function
// just replace '"' with '\"'.
std::string quote_string(const std::string &target);

std::string format_hex(const unsigned char *s, size_t len);

std::string http_date(time_t t);

// Returns given time |t| from epoch in Common Log format (e.g.,
// 03/Jul/2014:00:19:38 +0900)
std::string common_log_date(time_t t);

// Returns given millisecond |ms| from epoch in ISO 8601 format (e.g.,
// 2014-11-15T12:58:24.741Z)
std::string iso8601_date(int64_t ms);

time_t parse_http_date(const std::string &s);

template <typename InputIterator1, typename InputIterator2>
bool startsWith(InputIterator1 first1, InputIterator1 last1,
                InputIterator2 first2, InputIterator2 last2) {
  if (last1 - first1 < last2 - first2) {
    return false;
  }
  return std::equal(first2, last2, first1);
}

bool startsWith(const std::string &a, const std::string &b);

struct CaseCmp {
  bool operator()(char lhs, char rhs) const {
    if ('A' <= lhs && lhs <= 'Z') {
      lhs += 'a' - 'A';
    }
    if ('A' <= rhs && rhs <= 'Z') {
      rhs += 'a' - 'A';
    }
    return lhs == rhs;
  }
};

template <typename InputIterator1, typename InputIterator2>
bool istartsWith(InputIterator1 first1, InputIterator1 last1,
                 InputIterator2 first2, InputIterator2 last2) {
  if (last1 - first1 < last2 - first2) {
    return false;
  }
  return std::equal(first2, last2, first1, CaseCmp());
}

bool istartsWith(const std::string &a, const std::string &b);
bool istartsWith(const char *a, const char *b);
bool istartsWith(const char *a, size_t n, const char *b);

template <typename InputIterator1, typename InputIterator2>
bool endsWith(InputIterator1 first1, InputIterator1 last1,
              InputIterator2 first2, InputIterator2 last2) {
  if (last1 - first1 < last2 - first2) {
    return false;
  }
  return std::equal(first2, last2, last1 - (last2 - first2));
}

template <typename InputIterator1, typename InputIterator2>
bool iendsWith(InputIterator1 first1, InputIterator1 last1,
               InputIterator2 first2, InputIterator2 last2) {
  if (last1 - first1 < last2 - first2) {
    return false;
  }
  return std::equal(first2, last2, last1 - (last2 - first2), CaseCmp());
}

bool endsWith(const std::string &a, const std::string &b);

int strcompare(const char *a, const uint8_t *b, size_t n);

bool strieq(const std::string &a, const std::string &b);

bool strieq(const char *a, const char *b);

bool strieq(const char *a, const uint8_t *b, size_t n);

bool strieq(const char *a, const char *b, size_t n);

template <typename A, typename B>
bool streq(const A *a, const B *b, size_t bn) {
  if (!a || !b) {
    return false;
  }
  auto blast = b + bn;
  for (; *a && b != blast && *a == *b; ++a, ++b)
    ;
  return !*a && b == blast;
}

template <typename A, typename B>
bool streq(const A *a, size_t alen, const B *b, size_t blen) {
  if (alen != blen) {
    return false;
  }
  return memcmp(a, b, alen) == 0;
}

bool strifind(const char *a, const char *b);

char upcase(char c);

char lowcase(char c);

inline char lowcase(char c) {
  static unsigned char tbl[] = {
      0,   1,   2,   3,   4,   5,   6,   7,   8,   9,   10,  11,  12,  13,  14,
      15,  16,  17,  18,  19,  20,  21,  22,  23,  24,  25,  26,  27,  28,  29,
      30,  31,  32,  33,  34,  35,  36,  37,  38,  39,  40,  41,  42,  43,  44,
      45,  46,  47,  48,  49,  50,  51,  52,  53,  54,  55,  56,  57,  58,  59,
      60,  61,  62,  63,  64,  'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
      'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y',
      'z', 91,  92,  93,  94,  95,  96,  97,  98,  99,  100, 101, 102, 103, 104,
      105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119,
      120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134,
      135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149,
      150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164,
      165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179,
      180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194,
      195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209,
      210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224,
      225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239,
      240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254,
      255,
  };
  return tbl[static_cast<unsigned char>(c)];
}

// Lowercase |s| in place.
void inp_strlower(std::string &s);

// Returns string representation of |n| with 2 fractional digits.
std::string dtos(double n);

template <typename T> std::string utos(T n) {
  std::string res;
  if (n == 0) {
    res = "0";
    return res;
  }
  int i = 0;
  T t = n;
  for (; t; t /= 10, ++i)
    ;
  res.resize(i);
  --i;
  for (; n; --i, n /= 10) {
    res[i] = (n % 10) + '0';
  }
  return res;
}

template <typename T> std::string utos_with_unit(T n) {
  char u = 0;
  if (n >= (1 << 30)) {
    u = 'G';
    n /= (1 << 30);
  } else if (n >= (1 << 20)) {
    u = 'M';
    n /= (1 << 20);
  } else if (n >= (1 << 10)) {
    u = 'K';
    n /= (1 << 10);
  }
  if (u == 0) {
    return utos(n);
  }
  return utos(n) + u;
}

// Like utos_with_unit(), but 2 digits fraction part is followed.
template <typename T> std::string utos_with_funit(T n) {
  char u = 0;
  int b = 0;
  if (n >= (1 << 30)) {
    u = 'G';
    b = 30;
  } else if (n >= (1 << 20)) {
    u = 'M';
    b = 20;
  } else if (n >= (1 << 10)) {
    u = 'K';
    b = 10;
  }
  if (b == 0) {
    return utos(n);
  }
  return dtos(static_cast<double>(n) / (1 << b)) + u;
}

extern const char UPPER_XDIGITS[];

template <typename T> std::string utox(T n) {
  std::string res;
  if (n == 0) {
    res = "0";
    return res;
  }
  int i = 0;
  T t = n;
  for (; t; t /= 16, ++i)
    ;
  res.resize(i);
  --i;
  for (; n; --i, n /= 16) {
    res[i] = UPPER_XDIGITS[(n & 0x0f)];
  }
  return res;
}

void to_token68(std::string &base64str);
void to_base64(std::string &token68str);

void show_candidates(const char *unkopt, option *options);

bool has_uri_field(const http_parser_url &u, http_parser_url_fields field);

bool fieldeq(const char *uri1, const http_parser_url &u1, const char *uri2,
             const http_parser_url &u2, http_parser_url_fields field);

bool fieldeq(const char *uri, const http_parser_url &u,
             http_parser_url_fields field, const char *t);

std::string get_uri_field(const char *uri, const http_parser_url &u,
                          http_parser_url_fields field);

uint16_t get_default_port(const char *uri, const http_parser_url &u);

bool porteq(const char *uri1, const http_parser_url &u1, const char *uri2,
            const http_parser_url &u2);

void write_uri_field(std::ostream &o, const char *uri, const http_parser_url &u,
                     http_parser_url_fields field);

bool numeric_host(const char *hostname);

// Opens |path| with O_APPEND enabled.  If file does not exist, it is
// created first.  This function returns file descriptor referring the
// opened file if it succeeds, or -1.
int reopen_log_file(const char *path);

// Returns ASCII dump of |data| of length |len|.  Only ASCII printable
// characters are preserved.  Other characters are replaced with ".".
std::string ascii_dump(const uint8_t *data, size_t len);

// Returns absolute path of executable path.  If argc == 0 or |cwd| is
// nullptr, this function returns nullptr.  If argv[0] starts with
// '/', this function returns argv[0].  Oterwise return cwd + "/" +
// argv[0].  If non-null is returned, it is NULL-terminated string and
// dynamically allocated by malloc.  The caller is responsible to free
// it.
char *get_exec_path(int argc, char **const argv, const char *cwd);

// Validates path so that it does not contain directory traversal
// vector.  Returns true if path is safe.  The |path| must start with
// "/" otherwise returns false.  This function should be called after
// percent-decode was performed.
bool check_path(const std::string &path);

// Returns the |tv| value as 64 bit integer using a microsecond as an
// unit.
int64_t to_time64(const timeval &tv);

// Returns true if ALPN ID |proto| of length |len| is supported HTTP/2
// protocol identifier.
bool check_h2_is_selected(const unsigned char *alpn, size_t len);

// Selects h2 protocol ALPN ID if one of supported h2 versions are
// present in |in| of length inlen.  Returns true if h2 version is
// selected.
bool select_h2(const unsigned char **out, unsigned char *outlen,
               const unsigned char *in, unsigned int inlen);

// Returns default ALPN protocol list, which only contains supported
// HTTP/2 protocol identifier.
std::vector<unsigned char> get_default_alpn();

// Returns given time |tp| in Common Log format (e.g.,
// 03/Jul/2014:00:19:38 +0900)
// Expected type of |tp| is std::chrono::timepoint
template <typename T> std::string format_common_log(const T &tp) {
  auto t =
      std::chrono::duration_cast<std::chrono::seconds>(tp.time_since_epoch());
  return common_log_date(t.count());
}

// Returns given time |tp| in ISO 8601 format (e.g.,
// 2014-11-15T12:58:24.741Z)
// Expected type of |tp| is std::chrono::timepoint
template <typename T> std::string format_iso8601(const T &tp) {
  auto t = std::chrono::duration_cast<std::chrono::milliseconds>(
      tp.time_since_epoch());
  return iso8601_date(t.count());
}

// Return the system precision of the template parameter |Clock| as
// a nanosecond value of type |Rep|
template <typename Clock, typename Rep> Rep clock_precision() {
  std::chrono::duration<Rep, std::nano> duration = typename Clock::duration(1);

  return duration.count();
}

int make_socket_closeonexec(int fd);
int make_socket_nonblocking(int fd);
int make_socket_nodelay(int fd);

int create_nonblock_socket(int family);

bool check_socket_connected(int fd);

// Returns true if |host| is IPv6 numeric address (e.g., ::1)
bool ipv6_numeric_addr(const char *host);

// Parses NULL terminated string |s| as unsigned integer and returns
// the parsed integer.  Additionally, if |s| ends with 'k', 'm', 'g'
// and its upper case characters, multiply the integer by 1024, 1024 *
// 1024 and 1024 * 1024 respectively.  If there is an error, returns
// -1.
int64_t parse_uint_with_unit(const char *s);

// Parses NULL terminated string |s| as unsigned integer and returns
// the parsed integer.  If there is an error, returns -1.
int64_t parse_uint(const char *s);
int64_t parse_uint(const uint8_t *s, size_t len);
int64_t parse_uint(const std::string &s);

// Parses NULL terminated string |s| as unsigned integer and returns
// the parsed integer casted to double.  If |s| ends with "s", the
// parsed value's unit is a second.  If |s| ends with "ms", the unit
// is millisecond.  If none of them are given, the unit is second.
// This function returns std::numeric_limits<double>::infinity() if
// error occurs.
double parse_duration_with_unit(const char *s);

// Returns string representation of time duration |t|.  If t has
// fractional part (at least more than or equal to 1e-3), |t| is
// multiplied by 1000 and the unit "ms" is appended.  Otherwise, |t|
// is left as is and "s" is appended.
std::string duration_str(double t);

// Returns string representation of time duration |t|.  It appends
// unit after the formatting.  The available units are s, ms and us.
// The unit which is equal to or less than |t| is used and 2
// fractional digits follow.
std::string format_duration(const std::chrono::microseconds &u);

} // namespace util

} // namespace nghttp2

#endif // UTIL_H