#pragma once
#ifndef REAL_BUILD
# include "externals.hh"
#endif

struct T_SyncData;

namespace cops {

	struct T_Program;

	struct T_Context
	{
		T_Program const* program;

		float const* time;
		T_SyncData const* sync;

		T_KeyValueTable< T_String , float > vars;

		T_Array< float > opStack;

		T_Context& store(
			T_String const& name ,
			const float value );
	};

	class X_OpFailure : public std::exception
	{
	    public:
		X_OpFailure( ) = delete;
		DEF_COPY( X_OpFailure );
		DEF_MOVE( X_OpFailure );

		X_OpFailure(
			T_String const& source ,
			uint32_t line ,
			T_String&& error ) noexcept;

		T_String const& source( ) const noexcept
			{ return source_; }
		uint32_t line( ) const noexcept
			{ return line_; }
		T_String const& error( ) const noexcept
			{ return error_; }

		char const* what( ) const noexcept override;

	    private:
		T_String source_;
		uint32_t line_;
		T_String error_;
		T_String fullMessage_;
	};

	/*--------------------------------------------------------------------*/

	enum E_Op
	{
		OP_LOAD_CONSTANT ,
		OP_LOAD_VARIABLE ,
		OP_LOAD_INPUT ,
		OP_STORE_VARIABLE ,
		//
		OP_ADD , OP_MUL ,
		OP_NEG , OP_INV ,
		//
		OP_DUP , OP_XCHG ,
		//
		OP_SET_UNIFORM ,
		OP_USE_PIPELINE ,
		OP_USE_TEXTURE ,
		OP_USE_FRAMEBUFFER ,
		OP_SET_VIEWPORT ,
		//
		OP_CLEAR ,
		OP_FULLSCREEN ,
		//
		OP_CALL
	};

	struct T_Op
	{
		explicit T_Op(
			const E_Op op );
		virtual ~T_Op( ) = 0;

		E_Op op( ) const noexcept
			{ return op_; }

		virtual void execute(
			T_Context& ctx ) const = 0;

		T_String source{};
		uint32_t line{0};

	    protected:
		X_OpFailure error(
			ebcl::T_StringBuilder& message ) const noexcept;
		X_OpFailure error(
			T_String const& message ) const noexcept;

	    private:
		E_Op op_;
	};
	using P_Op = T_OwnPtr< T_Op >;
	using T_Operations = T_Array< P_Op >;

	template< typename T >
	inline T_Operations& operator <<(
			T_Operations& ops ,
			T&& item )
	{
		ops.add( NewOwned< T >( std::move( item ) ) );
		return ops;
	}

	void Execute(
		T_Operations const& operations ,
		T_Context& context );

	/*--------------------------------------------------------------------*/

	struct T_Function
	{
		T_String name;
		uint32_t arguments;
		T_Operations operations;

		T_Function( T_String const& name ,
				const uint32_t arguments )
			: name( name ) , arguments( arguments )
		{ }
		DEF_COPY( T_Function );
		DEF_MOVE( T_Function );
	};

	struct T_Program
	{
		T_ObjectTable< T_String , T_Function > functions;
		T_Operations main;

		T_Program( )
			: functions( []( T_Function const& f ) -> T_String {
						return f.name;
					} )
		{ }

		T_Operations& function(
				T_String const& name ,
				const uint32_t args );

		void execute( T_Context& context )
		{
			context.program = this;
			Execute( main , context );
		}
	};

	/*====================================================================*/

	struct OPLoadConstant : public T_Op
	{
		explicit OPLoadConstant(
			const float constant );
		void execute(
			T_Context& ctx ) const override;
		float constant;
	};

	struct OPLoadVariable : public T_Op
	{
		explicit OPLoadVariable(
			T_String const& variable );
		void execute(
			T_Context& ctx ) const override;
		T_String variable;
	};

	struct OPLoadInput : public T_Op
	{
		explicit OPLoadInput(
			T_String const& input );
		void execute(
			T_Context& ctx ) const override;
		T_String input;
	};

	struct OPStoreVariable : public T_Op
	{
		explicit OPStoreVariable(
			T_String const& variable );
		void execute(
			T_Context& ctx ) const override;
		T_String variable;
	};

	/*--------------------------------------------------------------------*/

	struct OPAdd : public T_Op
	{
		OPAdd( ) : T_Op( OP_ADD ) {}
		void execute(
			T_Context& ctx ) const override;
	};

	struct OPMul : public T_Op
	{
		OPMul( ) : T_Op( OP_MUL ) {}
		void execute(
			T_Context& ctx ) const override;
	};

	struct OPNeg : public T_Op
	{
		OPNeg( ) : T_Op( OP_NEG ) {}
		void execute(
			T_Context& ctx ) const override;
	};

	struct OPInv : public T_Op
	{
		OPInv( ) : T_Op( OP_INV ) {}
		void execute(
			T_Context& ctx ) const override;
	};

	/*--------------------------------------------------------------------*/

	struct OPDup : public T_Op
	{
		explicit OPDup( uint32_t stackIndex = 0 );
		void execute(
			T_Context& ctx ) const override;
		uint32_t stackIndex;
	};

	struct OPXchg : public T_Op
	{
		explicit OPXchg( uint32_t stackIndex = 1 );
		void execute(
			T_Context& ctx ) const override;
		uint32_t stackIndex;
	};

	/*--------------------------------------------------------------------*/

	struct OPSetUniform : public T_Op
	{
		OPSetUniform(
			const uint32_t count ,
			const bool integer );
		void execute(
			T_Context& ctx ) const override;

		uint32_t count;
		bool integer;
	};

	struct OPUsePipeline : public T_Op
	{
		explicit OPUsePipeline(
			const uint32_t index );
		void execute(
			T_Context& ctx ) const override;

		uint32_t pipeline;
	};

	struct OPUseTexture : public T_Op
	{
		OPUseTexture(
			const uint32_t binding ,
			const uint32_t texture ,
			const uint32_t sampler = 0 );
		void execute(
			T_Context& ctx ) const override;

		uint32_t binding;
		uint32_t texture;
		uint32_t sampler;
	};

	struct OPUseFramebuffer : public T_Op
	{
		explicit OPUseFramebuffer(
			const uint32_t framebuffer );
		void execute(
			T_Context& ctx ) const override;

		uint32_t framebuffer;
	};

	struct OPSetViewport : public T_Op
	{
		OPSetViewport( ) : T_Op( OP_SET_VIEWPORT ) { }
		void execute(
			T_Context& ctx ) const override;
	};

	/*--------------------------------------------------------------------*/

	struct OPClear : public T_Op
	{
		OPClear( ) : T_Op( OP_CLEAR ) { }
		void execute(
			T_Context& ctx ) const override;
	};

	struct OPFullscreen : public T_Op
	{
		OPFullscreen( ) : T_Op( OP_FULLSCREEN ) { }
		void execute(
			T_Context& ctx ) const override;
	};

	/*--------------------------------------------------------------------*/

	struct OPCall : public T_Op
	{
		explicit OPCall(
			T_String const& function );
		void execute(
			T_Context& ctx ) const override;

		T_String function;
	};

} // namespace cops