// Copyright (C) 2002-2008 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine" and the "irrXML" project.
// For conditions of distribution and use, see copyright notice in irrlicht.h and irrXML.h

#ifndef __IRR_STRING_H_INCLUDED__
#define __IRR_STRING_H_INCLUDED__

#include "irrTypes.h"
#include "irrAllocator.h"
#include "irrMath.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

namespace irr
{
namespace core
{

//! Very simple string class with some useful features.
/** string<c8> and string<wchar_t> both accept Unicode AND ASCII/Latin-1,
so you can assign Unicode to string<c8> and ASCII/Latin-1 to string<wchar_t>
(and the other way round) if you want to.

However, note that the conversation between both is not done using any encoding.
This means that c8 strings are treated as ASCII/Latin-1, not UTF-8, and 
are simply expanded to the equivalent wchar_t, while Unicode/wchar_t 
characters are truncated to 8-bit ASCII/Latin-1 characters, discarding all
other information in the wchar_t.

Known bugs:
Special characters like umlauts are ignored in the
methods make_upper, make_lower and equals_ignore_case.
*/
template <typename T, typename TAlloc = irrAllocator<T> >
class string
{
public:

	//! Default constructor
	string()
	: array(0), allocated(1), used(1)
	{
		array = allocator.allocate(1); // new T[1];
		array[0] = 0x0;
	}


	//! Constructor
	string(const string<T>& other)
	: array(0), allocated(0), used(0)
	{
		*this = other;
	}

	//! Constructor from other string types
	template <class B>
	string(const string<B>& other)
	: array(0), allocated(0), used(0)
	{
		*this = other;
	}


	//! Constructs a string from a float
	explicit string(const double number)
	: array(0), allocated(0), used(0)
	{
		c8 tmpbuf[255];
		snprintf(tmpbuf, 255, "%0.6f", number);
		*this = tmpbuf;
	}


	//! Constructs a string from an int
	explicit string(int number)
	: array(0), allocated(0), used(0)
	{
		// store if negative and make positive

		bool negative = false;
		if (number < 0)
		{
			number *= -1;
			negative = true;
		}

		// temporary buffer for 16 numbers

		c8 tmpbuf[16];
		tmpbuf[15] = 0;
		u32 idx = 15;

		// special case '0'

		if (!number)
		{
			tmpbuf[14] = '0';
			*this = &tmpbuf[14];
			return;
		}

		// add numbers

		while(number && idx)
		{
			--idx;
			tmpbuf[idx] = (c8)('0' + (number % 10));
			number /= 10;
		}

		// add sign

		if (negative)
		{
			--idx;
			tmpbuf[idx] = '-';
		}

		*this = &tmpbuf[idx];
	}


	//! Constructs a string from an unsigned int
	explicit string(unsigned int number)
	: array(0), allocated(0), used(0)
	{
		// temporary buffer for 16 numbers

		c8 tmpbuf[16];
		tmpbuf[15] = 0;
		u32 idx = 15;

		// special case '0'

		if (!number)
		{
			tmpbuf[14] = '0';
			*this = &tmpbuf[14];
			return;
		}

		// add numbers

		while(number && idx)
		{
			--idx;
			tmpbuf[idx] = (c8)('0' + (number % 10));
			number /= 10;
		}

		*this = &tmpbuf[idx];
	}


	//! Constructor for copying a string from a pointer with a given length
	template <class B>
	string(const B* const c, u32 length)
	: array(0), allocated(0), used(0)
	{
		if (!c)
		{
			// correctly init the string to an empty one
			*this="";
			return;
		}

		allocated = used = length+1;
		array = allocator.allocate(used); // new T[used];

		for (u32 l = 0; l<length; ++l)
			array[l] = (T)c[l];

		array[length] = 0;
	}


	//! Constructor for unicode and ascii strings
	template <class B>
	string(const B* const c)
	: array(0), allocated(0), used(0)
	{
		*this = c;
	}


	//! destructor
	~string()
	{
		allocator.deallocate(array); // delete [] array;
	}


	//! Assignment operator
	string<T>& operator=(const string<T>& other)
	{
		if (this == &other)
			return *this;

		allocator.deallocate(array); // delete [] array;
		allocated = used = other.size()+1;
		array = allocator.allocate(used); //new T[used];

		const T* p = other.c_str();
		for (u32 i=0; i<used; ++i, ++p)
			array[i] = *p;

		return *this;
	}

	//! Assignment operator for other string types
	template <class B>
	string<T>& operator=(const string<B>& other)
	{
		*this = other.c_str();
		return *this;
	}


	//! Assignment operator for strings, ascii and unicode
	template <class B>
	string<T>& operator=(const B* const c)
	{
		if (!c)
		{
			if (!array)
			{
				array = allocator.allocate(1); //new T[1];
				allocated = 1;
			}
			used = 1;
			array[0] = 0x0;
			return *this;
		}

		if ((void*)c == (void*)array)
			return *this;

		u32 len = 0;
		const B* p = c;
		while(*p)
		{
			++len;
			++p;
		}

		// we'll take the old string for a while, because the new
		// string could be a part of the current string.
		T* oldArray = array;

		++len;
		allocated = used = len;
		array = allocator.allocate(used); //new T[used];

		for (u32 l = 0; l<len; ++l)
			array[l] = (T)c[l];

		allocator.deallocate(oldArray); // delete [] oldArray;
		return *this;
	}


	//! Append operator for other strings
	string<T> operator+(const string<T>& other) const
	{
		string<T> str(*this);
		str.append(other);

		return str;
	}


	//! Append operator for strings, ascii and unicode
	template <class B>
	string<T> operator+(const B* const c) const
	{
		string<T> str(*this);
		str.append(c);

		return str;
	}


	//! Direct access operator
	T& operator [](const u32 index)
	{
		_IRR_DEBUG_BREAK_IF(index>=used) // bad index
		return array[index];
	}


	//! Direct access operator
	const T& operator [](const u32 index) const
	{
		_IRR_DEBUG_BREAK_IF(index>=used) // bad index
		return array[index];
	}


	//! Equality operator
	bool operator ==(const T* const str) const
	{
		if (!str)
			return false;

		u32 i;
		for(i=0; array[i] && str[i]; ++i)
			if (array[i] != str[i])
				return false;

		return !array[i] && !str[i];
	}


	//! Equality operator
	bool operator ==(const string<T>& other) const
	{
		for(u32 i=0; array[i] && other.array[i]; ++i)
			if (array[i] != other.array[i])
				return false;

		return used == other.used;
	}


	//! Is smaller comparator
	bool operator <(const string<T>& other) const
	{
		for(u32 i=0; array[i] && other.array[i]; ++i)
		{
			s32 diff = array[i] - other.array[i];
			if ( diff )
				return diff < 0;
/*
			if (array[i] != other.array[i])
				return (array[i] < other.array[i]);
*/
		}

		return used < other.used;
	}


	//! Inequality operator
	bool operator !=(const T* const str) const
	{
		return !(*this == str);
	}


	//! Inequality operator
	bool operator !=(const string<T>& other) const
	{
		return !(*this == other);
	}


	//! Returns length of string
	/** \return Length of the string in characters. */
	u32 size() const
	{
		return used-1;
	}


	//! Returns character string
	/** \return pointer to C-style zero terminated string. */
	const T* c_str() const
	{
		return array;
	}


	//! Makes the string lower case.
	void make_lower()
	{
		for (u32 i=0; i<used; ++i)
			array[i] = ansi_lower ( array[i] );
	}


	//! Makes the string upper case.
	void make_upper()
	{
		const T a = (T)'a';
		const T z = (T)'z';
		const T diff = (T)'A' - a;

		for (u32 i=0; i<used; ++i)
		{
			if (array[i]>=a && array[i]<=z)
				array[i] += diff;
		}
	}


	//! Compares the strings ignoring case.
	/** \param other: Other string to compare.
	\return True if the strings are equal ignoring case. */
	bool equals_ignore_case(const string<T>& other) const
	{
		for(u32 i=0; array[i] && other[i]; ++i)
			if (ansi_lower(array[i]) != ansi_lower(other[i]))
				return false;

		return used == other.used;
	}


	//! Compares the strings ignoring case.
	/** \param other: Other string to compare.
	\return True if this string is smaller ignoring case. */
	bool lower_ignore_case(const string<T>& other) const
	{
		for(u32 i=0; array[i] && other.array[i]; ++i)
		{
			s32 diff = (s32) ansi_lower ( array[i] ) - (s32) ansi_lower ( other.array[i] );
			if ( diff )
				return diff < 0;
		}

		return used < other.used;
	}


	//! compares the first n characters of the strings
	/** \param other Other string to compare.
	\param n Number of characters to compare
	\return True if the n first characters of this string are smaller. */
	bool equalsn(const string<T>& other, u32 n) const
	{
		u32 i;
		for(i=0; array[i] && other[i] && i < n; ++i)
			if (array[i] != other[i])
				return false;

		// if one (or both) of the strings was smaller then they
		// are only equal if they have the same length
		return (i == n) || (used == other.used);
	}


	//! compares the first n characters of the strings
	/** \param str Other string to compare.
	\param n Number of characters to compare
	\return True if the n first characters of this string are smaller. */
	bool equalsn(const T* const str, u32 n) const
	{
		if (!str)
			return false;
		u32 i;
		for(i=0; array[i] && str[i] && i < n; ++i)
			if (array[i] != str[i])
				return false;

		// if one (or both) of the strings was smaller then they
		// are only equal if they have the same length
		return (i == n) || (array[i] == 0 && str[i] == 0);
	}


	//! Appends a character to this string
	/** \param character: Character to append. */
	void append(T character)
	{
		if (used + 1 > allocated)
			reallocate(used + 1);

		++used;

		array[used-2] = character;
		array[used-1] = 0;
	}


	//! Appends a char string to this string
	/** \param other: Char string to append. */
	void append(const T* const other)
	{
		if (!other)
			return;

		u32 len = 0;
		const T* p = other;
		while(*p)
		{
			++len;
			++p;
		}

		if (used + len > allocated)
			reallocate(used + len);

		--used;
		++len;

		for (u32 l=0; l<len; ++l)
			array[l+used] = *(other+l);

		used += len;
	}


	//! Appends a string to this string
	/** \param other: String to append. */
	void append(const string<T>& other)
	{
		--used;
		u32 len = other.size()+1;

		if (used + len > allocated)
			reallocate(used + len);

		for (u32 l=0; l<len; ++l)
			array[used+l] = other[l];

		used += len;
	}


	//! Appends a string of the length l to this string.
	/** \param other: other String to append to this string.
	\param length: How much characters of the other string to add to this one. */
	void append(const string<T>& other, u32 length)
	{
		if (other.size() < length)
		{
			append(other);
			return;
		}

		if (used + length > allocated)
			reallocate(used + length);

		--used;

		for (u32 l=0; l<length; ++l)
			array[l+used] = other[l];
		used += length;

		// ensure proper termination
		array[used]=0;
		++used;
	}


	//! Reserves some memory.
	/** \param count: Amount of characters to reserve. */
	void reserve(u32 count)
	{
		if (count < allocated)
			return;

		reallocate(count);
	}


	//! finds first occurrence of character in string
	/** \param c: Character to search for.
	\return Position where the character has been found,
	or -1 if not found. */
	s32 findFirst(T c) const
	{
		for (u32 i=0; i<used; ++i)
			if (array[i] == c)
				return i;

		return -1;
	}

	//! finds first occurrence of a character of a list in string
	/** \param c: List of characters to find. For example if the method
	should find the first occurrence of 'a' or 'b', this parameter should be "ab".
	\param count: Amount of characters in the list. Usually,
	this should be strlen(c)
	\return Position where one of the characters has been found,
	or -1 if not found. */
	s32 findFirstChar(const T* const c, u32 count) const
	{
		if (!c)
			return -1;

		for (u32 i=0; i<used; ++i)
			for (u32 j=0; j<count; ++j)
				if (array[i] == c[j])
					return i;

		return -1;
	}


	//! Finds first position of a character not in a given list.
	/** \param c: List of characters not to find. For example if the method
	should find the first occurrence of a character not 'a' or 'b', this parameter should be "ab".
	\param count: Amount of characters in the list. Usually,
	this should be strlen(c)
	\return Position where the character has been found,
	or -1 if not found. */
	template <class B>
	s32 findFirstCharNotInList(const B* const c, u32 count) const
	{
		for (u32 i=0; i<used-1; ++i)
		{
			u32 j;
			for (j=0; j<count; ++j)
				if (array[i] == c[j])
					break;

			if (j==count)
				return i;
		}

		return -1;
	}

	//! Finds last position of a character not in a given list.
	/** \param c: List of characters not to find. For example if the method
	should find the first occurrence of a character not 'a' or 'b', this parameter should be "ab".
	\param count: Amount of characters in the list. Usually,
	this should be strlen(c)
	\return Position where the character has been found,
	or -1 if not found. */
	template <class B>
	s32 findLastCharNotInList(const B* const c, u32 count) const
	{
		for (s32 i=(s32)(used-2); i>=0; --i)
		{
			u32 j;
			for (j=0; j<count; ++j)
				if (array[i] == c[j])
					break;

			if (j==count)
				return i;
		}

		return -1;
	}

	//! finds next occurrence of character in string
	/** \param c: Character to search for.
	\param startPos: Position in string to start searching.
	\return Position where the character has been found,
	or -1 if not found. */
	s32 findNext(T c, u32 startPos) const
	{
		for (u32 i=startPos; i<used; ++i)
			if (array[i] == c)
				return i;

		return -1;
	}


	//! finds last occurrence of character in string
	/** \param c: Character to search for.
	\param start: start to search reverse ( default = -1, on end )
	\return Position where the character has been found,
	or -1 if not found. */
	s32 findLast(T c, s32 start = -1) const
	{
		start = core::clamp ( start < 0 ? (s32)(used) - 1 : start, 0, (s32)(used) - 1 );
		for (s32 i=start; i>=0; --i)
			if (array[i] == c)
				return i;

		return -1;
	}

	//! finds last occurrence of a character of a list in string
	/** \param c: List of strings to find. For example if the method
	should find the last occurrence of 'a' or 'b', this parameter should be "ab".
	\param count: Amount of characters in the list. Usually,
	this should be strlen(c)
	\return Position where one of the characters has been found,
	or -1 if not found. */
	s32 findLastChar(const T* const c, u32 count) const
	{
		if (!c)
			return -1;

		for (s32 i=used-1; i>=0; --i)
			for (u32 j=0; j<count; ++j)
				if (array[i] == c[j])
					return i;

		return -1;
	}


	//! finds another string in this string
	/** \param str: Another string
	\return Positions where the string has been found,
	or -1 if not found. */
	template <class B>
	s32 find(const B* const str) const
	{
		if (str && *str)
		{
			u32 len = 0;

			while (str[len])
				++len;

			if (len > used-1)
				return -1;

			for (u32 i=0; i<used-len; ++i)
			{
				u32 j=0;

				while(str[j] && array[i+j] == str[j])
					++j;

				if (!str[j])
					return i;
			}
		}

		return -1;
	}


	//! Returns a substring
	/** \param begin: Start of substring.
	\param length: Length of substring. */
	string<T> subString(u32 begin, s32 length) const
	{
		// if start after string
		// or no proper substring length
		if ((length <= 0) || (begin>=size()))
			return string<T>("");
		// clamp length to maximal value
		if ((length+begin) > size())
			length = size()-begin;

		string<T> o;
		o.reserve(length+1);

		for (s32 i=0; i<length; ++i)
			o.array[i] = array[i+begin];

		o.array[length] = 0;
		o.used = o.allocated;

		return o;
	}


	//! Appends a character to this string
	/** \param character: Character to append. */
	string<T>& operator += (T c)
	{
		append(c);
		return *this;
	}


	//! Appends a char string to this string
	/** \param other: Char string to append. */
	string<T>& operator += (const T* const c)
	{
		append(c);
		return *this;
	}


	//! Appends a string to this string
	/** \param other: String to append. */
	string<T>& operator += (const string<T>& other)
	{
		append(other);
		return *this;
	}


	string<T>& operator += (const int i)
	{
		append(string<T>(i));
		return *this;
	}


	string<T>& operator += (const unsigned int i)
	{
		append(string<T>(i));
		return *this;
	}


	string<T>& operator += (const long i)
	{
		append(string<T>(i));
		return *this;
	}


	string<T>& operator += (const unsigned long& i)
	{
		append(string<T>(i));
		return *this;
	}


	string<T>& operator += (const double i)
	{
		append(string<T>(i));
		return *this;
	}


	string<T>& operator += (const float i)
	{
		append(string<T>(i));
		return *this;
	}


	//! replaces all characters of a special type with another one
	void replace(T toReplace, T replaceWith)
	{
		for (u32 i=0; i<used; ++i)
			if (array[i] == toReplace)
				array[i] = replaceWith;
	}


	//! trims the string.
	/** Removes the specified characters (by default, Latin-1 whitespace) 
	from the begining and the end of the string. */
	string<T>& trim(const string<T> & whitespace = " \t\n\r")
	{
		// find start and end of the substring without the specified characters
		const s32 begin = findFirstCharNotInList(whitespace.c_str(), whitespace.used);
		if (begin == -1)
			return (*this="");

		const s32 end = findLastCharNotInList(whitespace.c_str(), whitespace.used);

		return (*this = subString(begin, (end +1) - begin));
	}


	//! Erases a character from the string.
	/** May be slow, because all elements
	following after the erased element have to be copied.
	\param index: Index of element to be erased. */
	void erase(u32 index)
	{
		_IRR_DEBUG_BREAK_IF(index>=used) // access violation

		for (u32 i=index+1; i<used; ++i)
			array[i-1] = array[i];

		--used;
	}

private:
/*
	T toLower(const T& t) const
	{
		if (t>=(T)'A' && t<=(T)'Z')
			return t + ((T)'a' - (T)'A');
		else
			return t;
	}
*/
	//! Returns a character converted to lower case
	inline T ansi_lower ( u32 x ) const
	{
		return x >= 'A' && x <= 'Z' ? (T) x + 0x20 : (T) x;
	}


	//! Reallocate the array, make it bigger or smaller
	void reallocate(u32 new_size)
	{
		T* old_array = array;

		array = allocator.allocate(new_size); //new T[new_size];
		allocated = new_size;

		u32 amount = used < new_size ? used : new_size;
		for (u32 i=0; i<amount; ++i)
			array[i] = old_array[i];

		if (allocated < used)
			used = allocated;

		allocator.deallocate(old_array); // delete [] old_array;
	}


	//--- member variables

	T* array;
	u32 allocated;
	u32 used;
	TAlloc allocator;
};


//! Typedef for character strings
typedef string<c8> stringc;

//! Typedef for wide character strings
typedef string<wchar_t> stringw;

} // end namespace core
} // end namespace irr

#endif