//
// Urho3D Engine
// Copyright (c) 2008-2011 Lasse Öörni
//
// 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.
//

#pragma once

#include "Iterator.h"
#include "Swap.h"

#include <cstring>
#include <ctype.h>

/// String class
class String
{
public:
    typedef RandomAccessIterator<char> Iterator;
    typedef RandomAccessConstIterator<char> ConstIterator;
    
    /// Construct empty
    String() :
        length_(0),
        capacity_(0),
        buffer_(&endZero)
    {
    }
    
    /// Construct from another string
    String(const String& str) :
        length_(0),
        capacity_(0),
        buffer_(&endZero)
    {
        *this = str;
    }
    
    /// Construct from a C string
    explicit String(const char* str) :
        length_(0),
        capacity_(0),
        buffer_(&endZero)
    {
        *this = str;
    }
    
    /// Destruct
    ~String()
    {
        if (capacity_)
            delete[] buffer_;
    }
    
    /// Assign a string
    String& operator = (const String& rhs)
    {
        Resize(rhs.length_);
        CopyChars(buffer_, rhs.buffer_, rhs.length_);
        
        return *this;
    }
    
    /// Assign a C string
    String& operator = (const char* rhs)
    {
        unsigned rhsLength = GetCStringLength(rhs);
        Resize(rhsLength);
        CopyChars(buffer_, rhs, rhsLength);
        
        return *this;
    }
    
    /// Add-assign a string
    String& operator += (const String& rhs)
    {
        if (rhs.length_)
        {
            unsigned oldLength = length_;
            Resize(length_ + rhs.length_);
            CopyChars(buffer_ + oldLength, rhs.buffer_, rhs.length_);
        }
        
        return *this;
    }
    
    /// Add-assign a C string
    String& operator += (const char* rhs)
    {
        unsigned rhsLength = GetCStringLength(rhs);
        if (rhsLength)
        {
            unsigned oldLength = length_;
            Resize(length_ + rhsLength);
            CopyChars(buffer_ + oldLength, rhs, rhsLength);
        }
        
        return *this;
    }
    
    /// Add-assign a character
    String& operator += (char rhs)
    {
        unsigned oldLength = length_;
        Resize(length_ + 1);
        buffer_[oldLength]  = rhs;
        
        return *this;
    }
    
    /// Add a string
    String operator + (const String& rhs) const
    {
        String ret;
        ret.Resize(length_ + rhs.length_);
        CopyChars(ret.buffer_, buffer_, length_);
        CopyChars(ret.buffer_ + length_, rhs.buffer_, rhs.length_);
        
        return ret;
    }
    
    /// Add a C string
    String operator + (const char* rhs) const
    {
        if (!rhs)
            return String(*this);
        
        unsigned rhsLength = strlen(rhs);
        if (!rhsLength)
            return String(*this);
        
        String ret;
        ret.Resize(length_ + rhsLength);
        CopyChars(ret.buffer_, buffer_, length_);
        CopyChars(ret.buffer_ + length_, rhs, rhsLength);
        
        return ret;
    }
    
    /// Add a character
    String operator + (char rhs) const
    {
        String ret(*this);
        ret += rhs;
        
        return ret;
    }
    
    /// Test for equality
    bool operator == (const String& rhs) const
    {
        if (rhs.length_ != length_)
            return false;
        
        for (unsigned i = 0; i < length_; ++i)
        {
            if (buffer_[i] != rhs.buffer_[i])
                return false;
        }
        
        return true;
    }
    
    /// Test for inequality with another string
    bool operator != (const String& rhs) const
    {
        if (rhs.length_ != length_)
            return true;
        
        for (unsigned i = 0; i < length_; ++i)
        {
            if (buffer_[i] != rhs.buffer_[i])
                return true;
        }
        
        return false;
    }
    
    /// Test if string is less than another string
    bool operator < (const String& rhs) const
    {
        for (unsigned i = 0; (i < length_) && (i < rhs.length_); ++i)
        {
            if (buffer_[i] < rhs.buffer_[i])
                return true;
            if (buffer_[i] > rhs.buffer_[i])
                return false;
        }
        
        return length_ < rhs.length_;
    }
    
    /// Test if string is greater than another string
    bool operator > (const String& rhs) const
    {
        for (unsigned i = 0; (i < length_) && (i < rhs.length_); ++i)
        {
            if (buffer_[i] > rhs.buffer_[i])
                return true;
            if (buffer_[i] < rhs.buffer_[i])
                return false;
        }
        
        return length_ > rhs.length_;
    }
    
    /// Return char at index
    char& operator [] (unsigned pos) { return buffer_[pos]; }
    /// Return const char at index
    const char& operator [] (unsigned pos) const { return buffer_[pos]; }
    
    /// Replace all occurrences of a character
    void Replace(char replaceThis, char replaceWith);
    /// Replace all occurrences of a string
    void Replace(const String& replaceThis, const String& replaceWith);
    /// Replace a substring
    void Replace(unsigned pos, unsigned length, const String& replaceWith);
    /// Replace a substring using iterators
    Iterator Replace(const Iterator& start, const Iterator& end, const String& replaceWith);
    /// Insert a string
    void Insert(unsigned pos, const String& str);
    /// Insert a character
    void Insert(unsigned pos, char c);
    /// Insert a string using an iterator
    Iterator Insert(const Iterator& dest, const String& str);
    /// Insert a string partially using iterators
    Iterator Insert(const Iterator& dest, const Iterator& start, const Iterator& end);
    /// Insert a character using an iterator
    Iterator Insert(const Iterator& dest, char c);
    /// Erase a substring
    void Erase(unsigned pos, unsigned length = 1);
    /// Erase a character using an iterator
    Iterator Erase(const Iterator& it);
    /// Erase a substring using iterators
    Iterator Erase(const Iterator& start, const Iterator& end);
    /// Resize the string
    void Resize(unsigned newLength);
    /// Set new capacity
    void Reserve(unsigned newCapacity);
    /// Reallocate so that no extra memory is used
    void Compact();
    /// Clear the string
    void Clear();
    /// Swap with another string
    void Swap(String& str);
    
    /// Return iterator to the beginning
    Iterator Begin() { return Iterator(buffer_); }
    /// Return const iterator to the beginning
    ConstIterator Begin() const { return ConstIterator(buffer_); }
    /// Return iterator to the end
    Iterator End() { return Iterator(buffer_ + length_); }
    /// Return const iterator to the end
    ConstIterator End() const { return ConstIterator(buffer_ + length_); }
    /// Return a substring from position to end
    String Substring(unsigned pos) const;
    /// Return a substring with length from position
    String Substring(unsigned pos, unsigned length) const;
    /// Return string with whitespace trimmed from the beginning and the end
    String Trim() const;
    /// Return string in uppercase
    String ToUpper() const;
    /// Return string in lowercase
    String ToLower() const;
    /// Find the first occurrence of a string, or NPOS if not found
    unsigned Find(const String& str, unsigned startPos = 0) const;
    /// Find the first occurrence of a character, or NPOS if not found
    unsigned Find(char c, unsigned startPos = 0) const;
    /// Find the last occurrence of a string, or NPOS if not found
    unsigned FindLast(const String& str) const;
    /// Find the last occurrence of a character, or NPOS if not found
    unsigned FindLast(char c) const;
    /// Return the C string
    const char* CString() const { return buffer_; }
    /// Return length
    unsigned Length() const { return length_; }
    /// Return buffer capacity
    unsigned Capacity() const { return capacity_; }
    /// Return whether the string is empty
    bool Empty() const { return length_ == 0; }
    
    /// Position for "not found"
    static const unsigned NPOS = 0xffffffff;
    /// Initial dynamic allocation size
    static const unsigned MIN_CAPACITY = 8;
    
private:
    /// Move a range of characters within the string
    void MoveRange(unsigned dest, unsigned src, unsigned count)
    {
        if (count)
            memmove(buffer_ + dest, buffer_ + src, count);
    }
    
    /// Copy chars from one buffer to another
    static void CopyChars(char* dest, const char* src, unsigned count)
    {
        #ifdef _MSC_VER
        if (count)
            memcpy(dest, src, count);
        #else
        char* end = dest + count;
        while (dest != end)
        {
            *dest = *src;
            ++dest;
            ++src;
        }
        #endif
    }
    
    /// Return length of a C string
    static unsigned GetCStringLength(const char* str)
    {
        if (!str)
            return 0;
        #ifdef _MSC_VER
        return strlen(str);
        #else
        const char* ptr = str;
        while (*ptr)
            ++ptr;
        return ptr - str;
        #endif
    }
    
    /// Replace a substring with another substring
    void Replace(unsigned pos, unsigned length, const char* srcStart, unsigned srcLength);
    
    /// String length
    unsigned length_;
    /// Capacity, zero if buffer not allocated
    unsigned capacity_;
    /// String buffer, null if not allocated
    char* buffer_;
    
    /// End zero for empty strings
    static char endZero;
};

/// Add a string to a C string
inline String operator + (const char* lhs, const String& rhs)
{
    String ret(lhs);
    ret += rhs;
    return ret;
}