//-----------------------------------------------------------------------------
// Copyright (c) 2012 GarageGames, LLC
//
// 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 _STRINGSTACK_H_
#define _STRINGSTACK_H_

#ifndef _STRINGFUNCTIONS_H_
#include "core/strings/stringFunctions.h"
#endif

#ifndef _STRINGTABLE_H_
#include "core/stringTable.h"
#endif

#ifndef _CONSOLE_H_
#include "console/console.h"
#endif

typedef U32 StringStackPtr;
struct StringStack;

/// Helper class which stores a relative pointer in the StringStack buffer
class StringStackPtrRef
{
public:
   StringStackPtrRef() : mOffset(0) {;}
   StringStackPtrRef(StringStackPtr offset) : mOffset(offset) {;}

   StringStackPtr mOffset;

   /// Get pointer to string in stack stk
   inline char *getPtr(StringStack *stk);
};

/// Core stack for interpreter operations.
///
/// This class provides some powerful semantics for working with strings, and is
/// used heavily by the console interpreter.
struct StringStack
{
   enum {
      MaxStackDepth = 1024,
      MaxArgs = 20,
      ReturnBufferSpace = 512
   };
   char *mBuffer;
   U32   mBufferSize;
   const char *mArgV[MaxArgs];
   U32 mFrameOffsets[MaxStackDepth];
   U32 mStartOffsets[MaxStackDepth];

   U32 mNumFrames;
   U32 mArgc;

   U32 mStart;
   U32 mLen;
   U32 mStartStackSize;
   U32 mFunctionOffset;

   U32 mArgBufferSize;
   char *mArgBuffer;

   void validateBufferSize(U32 size);
   void validateArgBufferSize(U32 size);

   StringStack();
   ~StringStack();

   /// Set the top of the stack to be an integer value.
   void setIntValue(U32 i);

   /// Set the top of the stack to be a float value.
   void setFloatValue(F64 v);

   /// Return a temporary buffer we can use to return data.
   char* getReturnBuffer(U32 size);

   /// Return a buffer we can use for arguments.
   ///
   /// This updates the function offset.
   char *getArgBuffer(U32 size);

   /// Clear the function offset.
   void clearFunctionOffset();

   /// Set a string value on the top of the stack.
   void setStringValue(const char *s);

   /// Get the top of the stack, as a StringTableEntry.
   ///
   /// @note Don't free this memory!
   inline StringTableEntry getSTValue()
   {
      return StringTable->insert(mBuffer + mStart);
   }

   /// Get an integer representation of the top of the stack.
   inline S64 getIntValue()
   {
      return dAtol(mBuffer + mStart);
   }

   /// Get a float representation of the top of the stack.
   inline F64 getFloatValue()
   {
      return dAtod(mBuffer + mStart);
   }

   /// Get a string representation of the top of the stack.
   ///
   /// @note This returns a pointer to the actual top of the stack, be careful!
   inline const char *getStringValue()
   {
      return mBuffer + mStart;
   }

   inline const char *getPreviousStringValue()
   {
      return mBuffer + mStartOffsets[mStartStackSize-1];
   }

   /// Advance the start stack, placing a zero length string on the top.
   ///
   /// @note You should use StringStack::push, not this, if you want to
   ///       properly push the stack.
   void advance();

   /// Advance the start stack, placing a single character, null-terminated strong
   /// on the top.
   ///
   /// @note You should use StringStack::push, not this, if you want to
   ///       properly push the stack.
   void advanceChar(char c);

   /// Push the stack, placing a zero-length string on the top.
   void push();

   inline void setLen(U32 newlen)
   {
      mLen = newlen;
   }

   /// Pop the start stack.
   void rewind();

   // Terminate the current string, and pop the start stack.
   void rewindTerminate();

   /// Compare 1st and 2nd items on stack, consuming them in the process,
   /// and returning true if they matched, false if they didn't.
   U32 compare();

   void clearFrames();
};

extern StringStack STR;

inline char* StringStackPtrRef::getPtr(StringStack *stk) { return stk->mBuffer + mOffset; }

#endif