// 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.

#include "nv/engine/program_manager.hh"
#include "nv/stl/range.hh"
#include "nv/core/logging.hh"
#include "nv/lua/lua_nova.hh"
#include "nv/io/c_file_system.hh"

nv::program_manager::program_manager( context* a_context ) : m_context( a_context )
{
	m_shader_head = a_context->get_device()->get_shader_header();
}

bool nv::program_manager::load_resource( lua::table_guard& table, shash64 id )
{
	NV_LOG_DEBUG( table.get_string("id") );
	string_buffer vsource;
	string_buffer fsource;
	string_buffer header( m_shader_head );
	if ( table.is_table("common") )
	{
		lua::table_guard common( table, "common" );
		header.append( "\n" + load_source( common, "" ) + "\n" );
	}
	{
		lua::table_guard vtable( table, "vertex" );
		vsource = load_source( vtable, header );
	}
	{
		lua::table_guard ftable( table, "fragment" );
		fsource = load_source( ftable, header );
	}

	add( m_context->get_device()->create_program( vsource, fsource ), id );
	return true;
}

void nv::program_manager::release( program p )
{
	m_context->get_device()->release( p );
}

nv::string_buffer nv::program_manager::load_source( lua::table_guard& table, const string_view& append )
{
	c_file_system fs;
	string_buffer out( append );
	if ( table.is_string( "files" ) )
	{
		out.append( fs.slurp( table.get_string( "files" ) ) );
	}
	else if ( table.is_table( "files" ) )
	{
		lua::table_guard inctable( table, "files" );
		uint32 count = inctable.get_size();
		for ( uint32 i = 1; i <= count; ++i )
		{
			const_string include( inctable.get<const_string,uint32>(i) );
			if ( i == count ) out.append( "#line 1\n" );
			out.append( fs.slurp( include ) );
		}
	}

	if ( table.is_string( "file" ) )
	{
		const_string data = fs.slurp( table.get_string( "file" ) );
		out.append( "#line 1\n" + data );
	}

	if ( table.is_string( "source" ) )
	{
		out.append( table.get_string( "source" ) );
	}
	return out;
}