// Copyright (C) 2014-2015 ChaosForge Ltd
// http://chaosforge.org/
//
// This file is part of Nova libraries. 
// For conditions of distribution and use, see copying.txt file in root folder.

/**
 * @file string_table.hh
 * @author Kornel Kisielewicz
 */

#ifndef NV_STL_STRING_TABLE_HH
#define NV_STL_STRING_TABLE_HH

#include <nv/common.hh>
#include <nv/stl/vector.hh>
#include <nv/stl/string.hh>
#include <nv/stl/unordered_map.hh>
#include <nv/stl/stream.hh>

namespace nv
{

	class string_table : noncopyable
	{
	public:
		typedef string_view value_type;
		typedef shash64 key_type;
		typedef uint64 hash_type;
		typedef uint32 size_type;
		typedef uint16 length_type;
		typedef unordered_map< hash_type, size_type > indexer_type;
		typedef vector< char > storage_type;
		typedef indexer_type::const_iterator const_iterator;

		string_table() {}
		string_table( stream& in );
		void insert( string_table* in );
		key_type insert( const value_type& str )
		{
			hash_type hash_value = str.get_hash< uint64 >();
			insert( hash_value, str );
			return key_type( hash_value );
		}

		bool exists( key_type i ) const 
		{
			return m_map.find( i.value() ) != m_map.end();
		}

		value_type at( key_type i ) const
		{
			const auto& it = m_map.find( i.value() );
			NV_ASSERT_ALWAYS( it != m_map.end(), "Key not found in string_table!" );
			return extract_raw( it->second );
		}

		value_type operator[]( key_type i ) const
		{
			const auto& it = m_map.find( i.value() );
			return it != m_map.end() ? extract_raw( it->second ) : value_type();
		}

		uint32 size() const { return m_map.size(); }
		bool empty() const { return m_map.empty(); }
		uint32 dump_size() const;
		void dump( stream& out ) const;
	protected:
		void insert( hash_type h, const value_type& str )
		{
			NV_ASSERT_ALWAYS( str.size() < 0xFFF0, "String table can only hold strings up to 64k!" );
			auto it = m_map.find( h );
			if ( it != m_map.end() )
			{
				// TODO : perform comparison check if in debug mode!
				return;
			}
			insert_raw( h, str.data(), static_cast<length_type>( str.size() ) );
		}


		size_type insert_raw( hash_type h, const char* str, length_type s );

		value_type extract_raw( size_type index ) const
		{
			uint16 length = *reinterpret_cast<const uint16*>( m_data.data() + index );
			return value_type( m_data.data() + index + 2, length );
		}

		indexer_type m_map;
		storage_type m_data;
	};

}

#endif // NV_STL_STRING_TABLE_HH