/*
 * Copyright 2006-2018 Adrian Thurston <thurston@colm.net>
 *
 * 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.
 */

#include "pcheck.h"

#include <stdbool.h>

/* Construct a new parameter checker with for paramSpec. */
ParamCheck::ParamCheck( const char *paramSpec, int argc,  const char **argv )
:
	state(noparam),
	argOffset(0),
	curArg(0),
	iCurArg(1),
	paramSpec(paramSpec), 
	argc(argc), 
	argv(argv)
{
}

/* Check a single option. Returns the index of the next parameter.  Sets p to
 * the arg character if valid, 0 otherwise.  Sets parg to the parameter arg if
 * there is one, NULL otherwise. */
bool ParamCheck::check()
{
	bool requiresParam;

	if ( iCurArg >= argc ) {            /* Off the end of the arg list. */
		state = noparam;
		return false;
	}

	if ( argOffset != 0 && *argOffset == 0 ) {
		/* We are at the end of an arg string. */
		iCurArg += 1;
		if ( iCurArg >= argc ) {
			state = noparam;
			return false;
		}
		argOffset = 0;
	}

	if ( argOffset == 0 ) {
		/* Set the current arg. */
		curArg = argv[iCurArg];

		/* We are at the beginning of an arg string. */
		if ( argv[iCurArg] == 0 ||        /* Argv[iCurArg] is null. */
			 argv[iCurArg][0] != '-' ||   /* Not a param. */
			 argv[iCurArg][1] == 0 ) {    /* Only a dash. */
			parameter = 0;
			parameterArg = 0;

			iCurArg += 1;
			state = noparam;
			return true;
		}
		argOffset = argv[iCurArg] + 1;
	}

	/* Get the arg char. */
	char argChar = *argOffset;
	
	/* Loop over all the parms and look for a match. */
	const char *pSpec = paramSpec;
	while ( *pSpec != 0 ) {
		char pSpecChar = *pSpec;

		/* If there is a ':' following the char then
		 * it requires a parm.  If a parm is required
		 * then move ahead two in the parmspec. Otherwise
		 * move ahead one in the parm spec. */
		if ( pSpec[1] == ':' ) {
			requiresParam = true;
			pSpec += 2;
		}
		else {
			requiresParam = false;
			pSpec += 1;
		}

		/* Do we have a match. */
		if ( argChar == pSpecChar ) {
			if ( requiresParam ) {
				if ( argOffset[1] == 0 ) {
					/* The param must follow. */
					if ( iCurArg + 1 == argc ) {
						/* We are the last arg so there
						 * cannot be a parameter to it. */
						parameter = argChar;
						parameterArg = 0;
						iCurArg += 1;
						argOffset = 0;
						state = invalid;
						return true;
					}
					else {
						/* the parameter to the arg is the next arg. */
						parameter = pSpecChar;
						parameterArg = argv[iCurArg + 1];
						iCurArg += 2;
						argOffset = 0;
						state = match;
						return true;
					}
				}
				else {
					/* The param for the arg is built in. */
					parameter = pSpecChar;
					parameterArg = argOffset + 1;
					iCurArg += 1;
					argOffset = 0;
					state = match;
					return true;
				}
			}
			else {
				/* Good, we matched the parm and no
				 * arg is required. */
				parameter = pSpecChar;
				parameterArg = 0;
				argOffset += 1;
				state = match;
				return true;
			}
		}
	}

	/* We did not find a match. Bad Argument. */
	parameter = argChar;
	parameterArg = 0;
	argOffset += 1;
	state = invalid;
	return true;
}