/*
 * FreeRTOS+CLI V1.0.4
 * Copyright (C) 2017 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * http://www.FreeRTOS.org
 * http://aws.amazon.com/freertos
 *
 * 1 tab == 4 spaces!
 */

/* Standard includes. */
#include <stdlib.h>
#include <string.h>
#include <stdint.h>

#include <debug.h>

/* Utils includes. */
#include <CLI.h>

#include "FreeRTOS_CLI.h"

/*
 * The callback function that is executed when "help" is entered.  This is the
 * only default command that is always present.
 */
static int prvHelpCommand( char *pcWriteBuffer, size_t xWriteBufferLen, const char *pcCommandString );

/*
 * Return the number of parameters that follow the command name.
 */
static int8_t prvGetNumberOfParameters( const char *pcCommandString );

/* The definition of the "help" command.  This command is always at the front
of the list of registered commands. */
static CLI_Command_Definition_t xHelpCommand =
{
	"help",
	"\r\nhelp:\r\n Lists all the registered commands\r\n\r\n",
	prvHelpCommand,
	NULL,
};

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

int CLIRegisterCommand( CLI_Command_Definition_t *pxCommandToRegister )
{
	static CLI_Command_Definition_t *pxLastCommandInList = &xHelpCommand;
	CLI_Command_Definition_t *pxNewListItem;

	/* Check the parameter is not NULL. */
	ASSERT( pxCommandToRegister );

	pxNewListItem = pxCommandToRegister;

	CLI_ENTER_CRITICAL()
	{
		/* The new list item will get added to the end of the list, so
		pxNext has nowhere to point. */
		pxNewListItem->pxNext = NULL;

		/* Add the newly created list item to the end of the already existing
		list. */
		pxLastCommandInList->pxNext = pxNewListItem;

		/* Set the end of list marker to the new list item. */
		pxLastCommandInList = pxNewListItem;
	}
	CLI_EXIT_CRITICAL()

	return CLI_TRUE;
}
/*-----------------------------------------------------------*/

int CLIProcessCommand( const char * const pcCommandInput, char * pcWriteBuffer, size_t xWriteBufferLen  )
{
	static const CLI_Command_Definition_t *pxCommand = NULL;
	int xReturn = CLI_TRUE;
	const char *pcRegisteredCommandString;
	size_t xCommandStringLength;

	/* Note:  This function is not re-entrant.  It must not be called from more
	thank one task. */

	if( pxCommand == NULL )
	{
		/* Search for the command string in the list of registered commands. */
		for( pxCommand = &xHelpCommand; pxCommand != NULL; pxCommand = pxCommand->pxNext )
		{
			pcRegisteredCommandString = pxCommand->pcCommand;
			xCommandStringLength = strlen( pcRegisteredCommandString );

			/* To ensure the string lengths match exactly, so as not to pick up
			a sub-string of a longer command, check the byte after the expected
			end of the string is either the end of the string or a space before
			a parameter. */
			if( ( pcCommandInput[ xCommandStringLength ] == ' ' ) || ( pcCommandInput[ xCommandStringLength ] == 0x00 ) )
			{
				if( strncmp( pcCommandInput, pcRegisteredCommandString, xCommandStringLength ) == 0 )
				{
					break;
				}
			}
		}
	}

	if( ( pxCommand != NULL ) && ( xReturn == CLI_FALSE ) )
	{
		/* The command was found, but the number of parameters with the command
		was incorrect. */
		strncpy( pcWriteBuffer, "Incorrect command parameter(s).  Enter \"help\" to view a list of available commands.\r\n\r\n", xWriteBufferLen );
		pxCommand = NULL;
	}
	else if( pxCommand != NULL )
	{
		/* Call the callback function that is registered to this command. */
		xReturn = pxCommand->pxCommandInterpreter( pcWriteBuffer, xWriteBufferLen, pcCommandInput );

		/* If xReturn is CLI_FALSE, then no further strings will be returned
		after this one, and	pxCommand can be reset to NULL ready to search
		for the next entered command. */
		if( xReturn == CLI_FALSE )
		{
			pxCommand = NULL;
		}
	}
	else
	{
		/* pxCommand was NULL, the command was not found. */
		strncpy( pcWriteBuffer, "Command not recognised.  Enter 'help' to view a list of available commands.\r\n\r\n", xWriteBufferLen );
		xReturn = CLI_FALSE;
	}

	return xReturn;
}

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

const char *CLIGetParameter( const char *pcCommandString, uint32_t uxWantedParameter, int *pxParameterStringLength )
{
	uint32_t uxParametersFound = 0;
	const char *pcReturn = NULL;

	*pxParameterStringLength = 0;

	while( uxParametersFound < uxWantedParameter )
	{
		/* Find the start of the next string. */
		while( ( ( *pcCommandString ) != 0x00 ) && ( ( *pcCommandString ) == ' ' ) )
		{
			pcCommandString++;
		}

		/* Was a string found? */
		if( *pcCommandString != 0x00 )
		{
			/* Is this the start of the required parameter? */
			uxParametersFound++;

			if( uxParametersFound == uxWantedParameter )
			{
				/* How long is the parameter? */
				pcReturn = pcCommandString;
				while( ( ( *pcCommandString ) != 0x00 ) && ( ( *pcCommandString ) != ' ' ) )
				{
					( *pxParameterStringLength )++;
					pcCommandString++;
				}

				if( *pxParameterStringLength == 0 )
				{
					pcReturn = NULL;
				}

				break;
			}
		}
		else
		{
			break;
		}
	}

	return pcReturn;
}
/*-----------------------------------------------------------*/

static int prvHelpCommand( char *pcWriteBuffer, size_t xWriteBufferLen, const char *pcCommandString )
{
	static const CLI_Command_Definition_t * pxCommand = NULL;
	int xReturn;

	( void ) pcCommandString;

	if( pxCommand == NULL )
	{
		/* Reset the pxCommand pointer back to the start of the list. */
		pxCommand = &xHelpCommand;
	}

	/* Return the next command help string, before moving the pointer on to
	the next command in the list. */
	strncpy( pcWriteBuffer, pxCommand->pcHelpString, xWriteBufferLen );
	pxCommand = pxCommand->pxNext;

	if( pxCommand == NULL )
	{
		/* There are no more commands in the list, so there will be no more
		strings to return after this one and CLI_FALSE should be returned. */
		xReturn = CLI_FALSE;
	}
	else
	{
		xReturn = CLI_TRUE;
	}

	return xReturn;
}
/*-----------------------------------------------------------*/

static int8_t prvGetNumberOfParameters( const char *pcCommandString )
{
	int8_t cParameters = 0;
	int xLastCharacterWasSpace = CLI_FALSE;

	/* Count the number of space delimited words in pcCommandString. */
	while( *pcCommandString != 0x00 )
	{
		if( ( *pcCommandString ) == ' ' )
		{
			if( xLastCharacterWasSpace != CLI_TRUE )
			{
				cParameters++;
				xLastCharacterWasSpace = CLI_TRUE;
			}
		}
		else
		{
			xLastCharacterWasSpace = CLI_FALSE;
		}

		pcCommandString++;
	}

	/* If the command string ended with spaces, then there will have been too
	many parameters counted. */
	if( xLastCharacterWasSpace == CLI_TRUE )
	{
		cParameters--;
	}

	/* The value returned is one less than the number of space delimited words,
	as the first word should be the command itself. */
	return cParameters;
}