// 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["id"].get_string() );
	string_buffer vsource;
	string_buffer fsource;
	string_buffer header( m_shader_head );
	if ( table["common"].is_table() )
	{
		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( id, m_context->create_program( vsource, fsource ) );
	return true;
}

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

nv::const_string nv::program_manager::file_to_string( const string_view& path )
{
	c_file_system fs;
	stream* fstream = open_stream( fs, path );
	if ( !fstream ) return const_string();
	uint32 size = static_cast< uint32 >( fstream->size() );
	const_string result( nullptr, size );
	fstream->read( const_cast<char*>( result.data() ), size, 1 );
	delete fstream;
	return result;
}

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["files"].is_string() )
	{
		out.append( file_to_string( table["files"].get_string() ) );
	}
	else if ( table["files"].is_table() )
	{
		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( file_to_string( include ) );
		}
	}

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

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