/* tester.c
 * 
 * An interactive test program for linkedlist.c
 *
 * AUTHORS:
 *
 * Rackham Hoke and Ashfaqur Rahman
 *
 * REVISION HISTORY:
 *
 * 2/17/00 by Rackham Hoke
 * - Added test cases for new library functions (see
 *   revision history in stringlist.c)
 * - NOTE: a description of all functions available in
 *   the tester is included in the help function.
 *     
 * 2/10/00 by Ashfaqur Rahman and Rackham Hoke
 * - Added test cases for:
 *     help()
 *     isEmpty()
 *     listFromFile()
 *     listToFile()
 *
 * 2/10/00 by Rackham Hoke
 * - Created this file and basic program structure.
 * - Implemented readLine().
 * - Added tester.c to Makefile.
 */


#include <stdio.h>
#include "stringlist.h"

#define MAX_LINE MAX_VALUE_LENGTH /* Maximum length of input. */


/*************************/
/* FUNCTION DECLARATIONS */
/*************************/


/* Reads a line from standard input. This function was written to
 * avoid the use of gets() while losing the newline character that
 * fgets() includes.
 * Preconditions: buf can hold up to max characters.
 * Postconditions: buf holds a line of input.
 * Problems: none.
 * Parameters:
 *   buf - the character array to read into.
 *   max - the maximum length of input.
 * Return: a pointer to buf.
 */
char* readLine(char* buf,int max);


/* Displays information on using the tester.
 * Preconditions: none.
 * Postconditions: information output to screen.
 * Problems: none.
 * Parameters: none.
 * Return: nothing.
 */
void printHelp(void);


/* The body of the program. */
int main(void) {
  stringList* list = newList();
  stringList* tmpList;            /* Used to check value returned by
			           * listFromFile(). */ 
  int writeSuccess;               /* Used to check value returned by
			           * listToFile(). */
  char command[MAX_LINE]; /* The command read from the prompt. */
  char value[MAX_LINE];   /* Additional values read from the prompt. */

  /* Present a friendly greeting. */
  printf("\nWelcome to the interactive linked list tester!\n");
  printf("An empty list has been created for you.\n\n");
  printHelp();

  /* Loop until the user quits explicitly. */
  while(1) {
    /* Display standard debugging information -- the current list,
     * current list reversed (verifies list integrity), and the current
     * node value. */
    printf("\nYour current list: ");
    listToScreen(list);
    printf("The list reversed: ");
    listToScreenReversed(list);
    printf("Current node: %s\n", currentValue(list));

    /* Prompt the user for input. */
    printf("\n>");
    readLine(command,MAX_LINE);

    /* Handle the various possible commands. */
    if (strcmp(command,"addToFront") == 0) {
      printf("What value? ");
      readLine(value,MAX_LINE);
      addToFront(list,value);
    }
    else if (strcmp(command,"addToEnd") == 0) {
      printf("What value? ");
      readLine(value,MAX_LINE);
      addToEnd(list,value);
    }
    else if (strcmp(command,"deleteCurrent") == 0) {
      deleteCurrent(list);
    }
    else if (strcmp(command,"quicksortList") == 0) {
      quicksortList(list);
    }
    else if (strcmp(command,"isEmpty") == 0) {
      if (isEmpty(list))
	printf("The list is empty.\n");
      else
	printf("The list is not empty.\n");
    }
    else if (strcmp(command,"moveNext") == 0) {
      if (!moveNext(list))
	printf("Already at the end of the list.\n");
    }
    else if (strcmp(command,"moveBack") == 0) {
      if (!moveBack(list))
	printf("Already at the front of the list.\n");
    }
    else if (strcmp(command,"atEnd") == 0) {
      if (atEnd(list))
	printf("You are at the end of the list.\n");
      else
	printf("You are not at the end of the list.\n");
    }
    else if (strcmp(command,"atFront") == 0) {
      if (atFront(list))
	printf("You are at the front of the list.\n");
      else
	printf("You are not at the front of the list.\n");
    }
    else if (strcmp(command,"listFromFile") == 0) {
      printf("Enter file name: ");
      readLine(value,MAX_LINE);
      tmpList = listFromFile(value);
      if (tmpList)
	list = tmpList;
      else
	printf("\nThere was trouble reading from the file.\n");
    }
    else if (strcmp(command,"listToFile") == 0) {
      printf("WARNING: previous data will be lost!\n");
      printf("Enter ! to cancel, or enter file name: ");

      /* Only continue if the user gives the go-ahead. */
      if (strcmp(readLine(value,MAX_LINE),"!") != 0) {
	writeSuccess = listToFile(list,value);
	if (!writeSuccess)
	  printf("There was an error writing the list to the file.\n");
	else
	  printf("File written.\n");
      }
      else
	printf("File operation canceled.\n");
    }
    else if (strcmp(command,"reverseList") == 0) {
      reverseList(list);
    }
    else if (strcmp(command,"resetCurrent") == 0) {
      resetCurrent(list);
    }
    else if (strcmp(command,"help") == 0) {
      printHelp();
    }
    else if (strcmp(command,"quit") == 0) {
      return(0);
    }
    else
      printf("Unknown command.\n");
  }
}


/* BEGIN readLine() */
char* readLine(char* buf,int max) {
  char* nlPos;    /* The position of the newline */

  /* Get the input, including newline */
  fgets(buf,max,stdin);

  /* Replace the newline with a string terminator */
  nlPos = (char*) strchr(buf,'\n');
  if (nlPos)
    *nlPos = '\0';

  return buf;
}
/* END readLine() */


/* BEGIN printHelp() */
void printHelp(void) {
  /* Let the user know the options */
  printf("You have your choice of the following operations:\n\n");
  printf("addToFront     -Adds a value to the front of the list.\n");
  printf("addToEnd       -Adds a value to the end of the list.\n");
  printf("deleteCurrent  -Deletes the current node in the list.\n");
  printf("quicksortList  -Sorts the list by value.\n");
  printf("isEmpty        -Tells you if the list is empty.\n");
  printf("moveNext       -Advances the current node.\n");
  printf("moveBack       -Moves back the current node.\n");
  printf("atEnd          -Tells if you've reached the end of the list.\n");
  printf("atFront        -Tells if you've reached the front of the list.\n");
  printf("listFromFile   -Reads a list from a file.\n");
  printf("listToFile     -Writes the current list to a file.\n");
  printf("reverseList    -Reverses the list.\n");
  printf("resetCurrent   -Sets current node to front of the list.\n");
  printf("help           -Display this help message.\n");
  printf("quit           -Quit the tester.\n\n");
}
/* END printHelp() */