//===-- MICmnStreamStdinLinux.cpp --------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

//++
// File:		MIUtilStreamStdin.cpp
//
// Overview:	CMICmnStreamStdinLinux implementation.
//
// Environment:	Compilers:	Visual C++ 12.
//							gcc (Ubuntu/Linaro 4.8.1-10ubuntu9) 4.8.1
//				Libraries:	See MIReadmetxt. 
//
// Copyright:	None.
//--

// Third Party Headers:
#if !defined( _MSC_VER )
#include <sys/select.h>
#include <termios.h>
#endif // !defined( _MSC_VER )
#include <string.h> // For std::strerror()

// In-house headers:
#include "MICmnStreamStdinLinux.h"
#include "MICmnLog.h"
#include "MICmnResources.h"
#include "MIUtilSingletonHelper.h"

//++ ------------------------------------------------------------------------------------
// Details:	CMICmnStreamStdinLinux constructor.
// Type:	Method.
// Args:	None.
// Return:	None.
// Throws:	None.
//--
CMICmnStreamStdinLinux::CMICmnStreamStdinLinux( void )
:	m_constBufferSize( 1024 )
,	m_pStdin( nullptr )
,	m_pCmdBuffer( nullptr )
{
}

//++ ------------------------------------------------------------------------------------
// Details:	CMICmnStreamStdinLinux destructor.
// Type:	Overridable.
// Args:	None.
// Return:	None.
// Throws:	None.
//--
CMICmnStreamStdinLinux::~CMICmnStreamStdinLinux( void )
{
	Shutdown();
}

//++ ------------------------------------------------------------------------------------
// Details:	Initialize resources for *this Stdin stream.
// Type:	Method.
// Args:	None.
// Return:	MIstatus::success - Functional succeeded.
//			MIstatus::failure - Functional failed.
// Throws:	None.
//--
bool CMICmnStreamStdinLinux::Initialize( void )
{
	if( m_bInitialized )
		return MIstatus::success;

	bool bOk = MIstatus::success;
	CMIUtilString errMsg;
 
	// Note initialisation order is important here as some resources depend on previous
	MI::ModuleInit< CMICmnLog >      ( IDS_MI_INIT_ERR_LOG      , bOk, errMsg );
	MI::ModuleInit< CMICmnResources >( IDS_MI_INIT_ERR_RESOURCES, bOk, errMsg );

	// Other resources required
	if( bOk )
	{
		m_pCmdBuffer = new MIchar[ m_constBufferSize ];
		m_pStdin = stdin;
	}

	// Clear error indicators for std input
	::clearerr( stdin );

	m_bInitialized = bOk;

	if( !bOk )
	{
		CMIUtilString strInitError( CMIUtilString::Format( MIRSRC( IDS_MI_INIT_ERR_OS_STDIN_HANDLER ), errMsg.c_str() ) );
		SetErrorDescription( strInitError );
		return MIstatus::failure;
	}

	return  MIstatus::success;
}

//++ ------------------------------------------------------------------------------------
// Details:	Release resources for *this Stdin stream.
// Type:	Method.
// Args:	None.
// Return:	MIstatus::success - Functional succeeded.
//			MIstatus::failure - Functional failed.
// Throws:	None.
//--
bool CMICmnStreamStdinLinux::Shutdown( void )
{
	if( !m_bInitialized )
		return MIstatus::success;

	m_bInitialized = false;

	ClrErrorDescription();

	bool bOk = MIstatus::success;
	CMIUtilString errMsg;

	// Tidy up
	if( m_pCmdBuffer != nullptr )
	{
		delete [] m_pCmdBuffer;
		m_pCmdBuffer = nullptr;
	}
	m_pStdin = nullptr;

	// Note shutdown order is important here 	
	MI::ModuleShutdown< CMICmnResources >( IDS_MI_INIT_ERR_RESOURCES, bOk, errMsg );
	MI::ModuleShutdown< CMICmnLog >      ( IDS_MI_INIT_ERR_LOG      , bOk, errMsg );

	if( !bOk )
	{
		SetErrorDescriptionn( MIRSRC( IDS_MI_SHTDWN_ERR_OS_STDIN_HANDLER ), errMsg.c_str() );
	}

	return MIstatus::success;
}	

//++ ------------------------------------------------------------------------------------
// Details:	Determine if stdin has any characters present in its buffer.
// Type:	Method.
// Args:	vwbAvail	- (W) True = There is chars available, false = nothing there.
// Return:	MIstatus::success - Functional succeeded.
//			MIstatus::failure - Functional failed.
// Throws:	None.
//--
bool CMICmnStreamStdinLinux::InputAvailable( bool & vwbAvail )
{
#ifndef _MSC_VER
/* AD: Not used ATM but could come in handy just in case we need to do
       this, poll for input

	static const int STDIN = 0;
    static bool bInitialized = false;

    if( !bInitialized )
	{
        // Use termios to turn off line buffering
        ::termios term;
        ::tcgetattr( STDIN, &term );
        ::term.c_lflag &= ~ICANON;
        ::tcsetattr( STDIN, TCSANOW, &term );
        ::setbuf( stdin, NULL );
        bInitialized = true;
    }

    int nBytesWaiting;
    ::ioctl( STDIN, FIONREAD, &nBytesWaiting );
    vwbAvail = (nBytesWaiting > 0);

	return MIstatus::success;
*/
#endif // ifndef _MSC_VER

	return MIstatus::success;
}

//++ ------------------------------------------------------------------------------------
// Details:	Wait on new line of data from stdin stream (completed by '\n' or '\r').
// Type:	Method.
// Args:	vwErrMsg	- (W) Empty string ok or error description.			
// Return:	MIchar * - text buffer pointer or NULL on failure.
// Throws:	None.
//--
const MIchar * CMICmnStreamStdinLinux::ReadLine( CMIUtilString & vwErrMsg )
{
	vwErrMsg.clear();
	
	// Read user input
	const MIchar * pText = ::fgets( &m_pCmdBuffer[ 0 ], m_constBufferSize, stdin );
	if( pText == nullptr )
	{
		if( ::ferror( m_pStdin ) != 0 )
			vwErrMsg = ::strerror( errno );
		return nullptr;
	}

    // Strip off new line characters
	for( MIchar * pI = m_pCmdBuffer; *pI != '\0'; pI++ )
	{
		if( (*pI == '\n') || (*pI == '\r') )
		{
			*pI = '\0';
			break;
		}
	}

	return pText;
}
