/*
 *  Phusion Passenger - https://www.phusionpassenger.com/
 *  Copyright (c) 2010-2017 Phusion Holding B.V.
 *
 *  "Passenger", "Phusion Passenger" and "Union Station" are registered
 *  trademarks of Phusion Holding B.V.
 *
 *  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 _PASSENGER_STR_INT_UTILS_H_
#define _PASSENGER_STR_INT_UTILS_H_

#include <string>
#include <vector>
#include <ostream>
#include <sstream>
#include <stdexcept>
#include <new>
#include <cstdlib>
#include <cstddef>
#include <ctime>
#include <boost/move/utility.hpp>
#include <oxt/macros.hpp>
#include <StaticString.h>

namespace Passenger {

using namespace std;


/**
 * A RAII construct for memory buffers that are dynamically allocated with malloc().
 * Upon destruction of a DynamicBuffer, the memory buffer is freed.
 */
struct DynamicBuffer {
private:
	BOOST_MOVABLE_BUT_NOT_COPYABLE(DynamicBuffer)

public:
	typedef string::size_type size_type;

	char *data;
	size_type size;

	DynamicBuffer()
		: data(NULL),
		  size(0)
		{ }

	/**
	 * @throws std::bad_alloc The buffer cannot be allocated.
	 */
	DynamicBuffer(size_type _size)
		: size(_size)
	{
		data = (char *) malloc(_size);
		if (data == NULL) {
			throw std::bad_alloc();
		}
	}

	DynamicBuffer(BOOST_RV_REF(DynamicBuffer) other)
		: data(other.data),
		  size(other.size)
	{
		other.data = NULL;
		other.size = 0;
	}

	~DynamicBuffer() throw() {
		free(data);
	}

	DynamicBuffer &operator=(BOOST_RV_REF(DynamicBuffer) other) {
		if (this != &other) {
			free(data);
			data = other.data;
			size = other.size;
			other.data = NULL;
			other.size = 0;
		}
		return *this;
	}
};


/**
 * Given a prefix string, a middle string and a postfix string, try to build a string
 * that looks like <tt>prefix + middle + postfix</tt>, with as many characters from
 * <tt>midle</tt> preserved as possible.
 *
 * If <tt>prefix + middle + postfix</tt> does not fit in <tt>max</tt> characters,
 * then <tt>middle</tt> will be truncated so that it fits. If <tt>max</tt> is too
 * small to contain even 1 character from <tt>middle</tt>, then an ArgumentException
 * will be thrown.
 *
 * @code
 *   fillInMiddle(18, "server.", "1234", ".socket");    // "server.1234.socket"
 *   fillInMiddle(16, "server.", "1234", ".socket");    // "server.12.socket"
 *   fillInMiddle(14, "server.", "1234", ".socket");    // ArgumentException
 * @endcode
 *
 * @returns The resulting string, with <tt>middle</tt> possibly truncated.
 * @throws ArgumentException <tt>max</tt> is too small to contain even 1
 *         character from <tt>middle</tt>.
 * @post result.size() <= max
 */
string fillInMiddle(unsigned int max, const string &prefix, const string &middle,
	const string &postfix = "");

/**
 * Checks whether <tt>str</tt> starts with <tt>substr</tt>.
 */
bool startsWith(const StaticString &str, const StaticString &substr);

/**
 * Checks whether <tt>str</tt> ends with <tt>substr</tt>.
 */
bool endsWith(const StaticString &str, const StaticString &substr);

/**
 * Split the given string using the given separator. Excludes the
 * separator from the output.
 *
 * @param str The string to split.
 * @param sep The separator to use.
 * @param output The vector to write the output to.
 */
void split(const StaticString & restrict_ref str,
	char sep,
	vector<string> & restrict_ref output);
void split(const StaticString & restrict_ref str,
	char sep,
	vector<StaticString> & restrict_ref output);

/**
 * Split the given string using the given separator. Includes the
 * separator in the output, at the end of an item.
 *
 * @param str The string to split.
 * @param sep The separator to use.
 * @param output The vector to write the output to.
 */
void splitIncludeSep(const StaticString & restrict_ref str,
	char sep,
	vector<string> & restrict_ref output);
void splitIncludeSep(const StaticString & restrict_ref str,
	char sep,
	vector<StaticString> & restrict_ref output);

/**
 * Each section in str ending with any of the tokens is truncated to a length of maxBetweenTokens.
 * The result is streamed to sstream, including tokens.
 *
 * Example: ("hello/world\\path/Splitter.cpp", "\\/", 3, sstream) results in sstream << "hel/wor\\pat/Splitter.cpp"
 */
void truncateBeforeTokens(const char *str, const StaticString &tokens, int maxBetweenTokens, ostream &sstream);

/**
 * Look for 'toFind' inside 'str', replace it with 'replaceWith' and return the result.
 * Only the first occurence of 'toFind' is replaced.
 */
string replaceString(const StaticString &str, const StaticString &toFind, const StaticString &replaceWith);

/**
 * Like replaceString(), but replace all occurrences of `toFind`.
 */
string replaceAll(const StaticString &str, const StaticString &toFind, const StaticString &replaceWith);

/**
 * Strips leading and trailing whitespaces.
 */
string strip(const StaticString &str);

/**
 * Given a pointer to a NULL-terminated string, update it to a
 * position where all leading whitespaces (0x20) have been skipped.
 */
inline void
skipLeadingWhitespaces(const char **data) {
	while (**data == ' ') {
		(*data)++;
	}
}

/**
 * Given a pointer to a string and its end, update the begin pointer to a
 * position where all leading whitespaces (0x20) have been skipped.
 * The pointer will not be moved past `end`.
 */
inline void
skipLeadingWhitespaces(const char **data, const char *end) {
	while (*data < end && **data == ' ') {
		(*data)++;
	}
}

/**
 * Given a string and a pointer to its position within it, update the pointer
 * to a position where all trailing whitespaces (0x20) have been skipped.
 * The pointer will not be moved before `begin`.
 */
inline void
skipTrailingWhitespaces(const char *begin, const char **pos) {
	while (*pos > begin && (*pos)[-1] == ' ') {
		(*pos)--;
	}
}

/**
 * Convert anything to a string.
 */
template<typename T> string
toString(T something) {
	stringstream s;
	s << something;
	return s.str();
}

string toString(const vector<string> &vec);
string toString(const vector<StaticString> &vec);

string doubleToString(double value);
string pointerToIntString(void *pointer);

/**
 * Converts the given integer string to an unsigned long long integer.
 */
unsigned long long stringToULL(const StaticString &str);
unsigned int stringToUint(const StaticString &str);

/**
 * Converts the given integer string to a long long integer.
 */
long long stringToLL(const StaticString &str);
int stringToInt(const StaticString &str);

/**
 * Converts the given hexadecimal string to an unsigned long long integer.
 */
unsigned long long hexToULL(const StaticString &str);
unsigned int hexToUint(const StaticString &str);

/**
 * Converts the given hexatridecimal (base 36) string to an unsigned long long integer.
 */
unsigned long long hexatriToULL(const StaticString &str);

/**
 * Convert the given binary data to hexadecimal.
 */
string toHex(const StaticString &data);

/**
 * Convert the given binary data to hexadecimal. This form accepts an
 * output buffer which must be at least <tt>data.size() * 2</tt> bytes large.
 */
void toHex(const StaticString & restrict_ref data, char * restrict output, bool upperCase = false);

/**
 * Reverse a string in-place.
 */
void reverseString(char *str, unsigned int size);

/**
 * Calculates the size (in characters) of an integer when converted
 * to another base.
 */
template<typename IntegerType, int radix>
unsigned int
integerSizeInOtherBase(IntegerType value) {
	IntegerType remainder = value;
	unsigned int size = 0;

	do {
		remainder = remainder / radix;
		size++;
	} while (remainder != 0);

	return size;
}

/**
 * Convert the given integer to some other radix, placing
 * the result into the given output buffer. The output buffer
 * will be NULL terminated. Supported radices are 2-36.
 *
 * @param outputSize The size of the output buffer, including space for
 *                   the terminating NULL.
 * @return The size of the created string, excluding
 *         terminating NULL.
 * @throws std::length_error The output buffer is not large enough.
 */
template<typename IntegerType, int radix>
unsigned int
integerToOtherBase(IntegerType value, char *output, unsigned int outputSize) {
	static const char chars[] = {
		'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
		'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'
	};
	IntegerType remainder = value;
	unsigned int size = 0;

	if (outputSize >= 4) {
		if (value < radix) {
			output[0] = chars[value];
			output[1] = '\0';
			return 1;
		} else if (value < radix * radix) {
			output[0] = chars[value / radix];
			output[1] = chars[value % radix];
			output[2] = '\0';
			return 2;
		} else if ((long long) value < radix * radix * radix) {
			output[0] = chars[value / radix / radix];
			output[1] = chars[value / radix % radix];
			output[2] = chars[value % radix];
			output[3] = '\0';
			return 3;
		}
	}

	do {
		output[size] = chars[remainder % radix];
		remainder = remainder / radix;
		size++;
	} while (remainder != 0 && size < outputSize - 1);

	if (remainder == 0) {
		reverseString(output, size);
		output[size] = '\0';
		return size;
	} else {
		throw std::length_error("Buffer not large enough to for integerToOtherBase()");
		return -1; // Shut up compiler warning.
	}
}

/**
 * Convert the given integer to hexadecimal, placing the result
 * into the given output buffer. This buffer must be at least
 * <tt>2 * sizeof(IntegerType) + 1</tt> bytes. The output buffer
 * will be NULL terminated.
 *
 * @return The size of the created hexadecimal string, excluding
 *         terminating NULL.
 */
template<typename IntegerType>
unsigned int
integerToHex(IntegerType value, char *output) {
	return integerToOtherBase<IntegerType, 16>(value, output, 2 * sizeof(IntegerType) + 1);
}

unsigned int uintSizeAsString(unsigned int value);
unsigned int uintToString(unsigned int value, char *output, unsigned int outputSize);

/**
 * Convert the given integer to a hexadecimal string.
 */
string integerToHex(long long value);

/**
 * Convert the given integer to hexatridecimal (Base 36), placing the
 * result into the given output buffer. This buffer must be at least
 * <tt>2 * sizeof(IntegerType) + 1</tt> bytes. The output buffer
 * will be NULL terminated.
 *
 * @return The size of the created hexatridecimal string, excluding
 *         terminating NULL.
 */
template<typename IntegerType>
unsigned int
integerToHexatri(IntegerType value, char *output) {
	return integerToOtherBase<IntegerType, 36>(value, output, 2 * sizeof(IntegerType) + 1);
}

/**
 * Convert the given integer to a hexatridecimal string.
 */
string integerToHexatri(long long value);

/**
 * Checks whether the given string looks like a number >= 0.
 */
bool looksLikePositiveNumber(const StaticString &str);

/**
 * Converts the given string to an integer.
 */
int atoi(const string &s);

/**
 * Converts the given string to a long integer.
 */
long atol(const string &s);

/**
 * Round `number` up to the nearest multiple of `multiple`.
 * This only works for integers!
 */
template<typename IntegerType>
IntegerType
roundUp(IntegerType number, IntegerType multiple) {
	return (number + multiple - 1) / multiple * multiple;
}

/**
 * Converts the given character array to lowercase.
 */
void convertLowerCase(const unsigned char * restrict data, unsigned char * restrict output, size_t len);

/**
 * Compare two strings using a constant time algorithm to avoid timing attacks.
 */
bool constantTimeCompare(const StaticString &a, const StaticString &b);

string distanceOfTimeInWords(time_t fromTime, time_t toTime = 0);

/**
 * Returns the amount of time to the next multiple of `multiple`. For example:
 *
 *     timeToNextMultipleULL(5, 0);   // => 5
 *     timeToNextMultipleULL(5, 1);   // => 4
 *     timeToNextMultipleULL(5, 2);   // => 3
 *     timeToNextMultipleULL(5, 3);   // => 2
 *     timeToNextMultipleULL(5, 4);   // => 1
 *     timeToNextMultipleULL(5, 5);   // => 5
 *     timeToNextMultipleULL(5, 6);   // => 4
 *
 * `multiple` and `now` may be in any unit (seconds, microseconds, hours) as
 * long as they are both the same unit. The return value is then also in that unit.
 * `timeToNextMultipleULL` operates on timestamp integers while
 * `timeToNextMultipleD` operates on timestamp floating point numbers.
 *
 * In case of `timeToNextMultipleULL`, if `now` is 0, then it is automatically set to
 * `SystemTime::getUsec()`.
 *
 * This function is mainly useful for repeating a timer while aligning the repeat
 * time on a certain multiple, which saves power on laptops. For example, when
 * repeating a libev timer you can call the following in the timeout function:
 *
 *     timer->repeat = timeToNextMultipleD(5, ev_now(loop));
 *     ev_timer_again(loop, timer);
 */
unsigned long long timeToNextMultipleULL(unsigned long long multiple, unsigned long long now = 0);
double timeToNextMultipleD(unsigned int multiple, double now);

/**
 * Append the given data to the address at 'pos', but do not cross 'end'.
 * Returns the end of the appended string.
 */
char *appendData(char *pos, const char *end, const char *data, size_t size);
char *appendData(char *pos, const char *end, const StaticString &data);

/**
 * Escape non-ASCII-printable characters in the given string with C-style escape sequences,
 * e.g. "foo\nbar\0" becomes "foo\\nbar\\0".
 */
string cEscapeString(const StaticString &input);

/**
 * Escapes HTML special characters the given input string, which is assumed to
 * contain UTF-8 data. Returns a UTF-8 encoded string.
 *
 * @throws utf8::exception A UTF-8 decoding error occurred.
 */
string escapeHTML(const StaticString &input);

/**
 * URL-decodes the given string.
 *
 * @throws SyntaxError
 */
string urldecode(const StaticString &url);

} // namespace Passenger

#endif /* _PASSENGER_STR_INT_UTILS_H_ */