/*
 * This is an example program to introduce some of the basic features
 * of C, including linked list.
 *
 * CSCI 315
 * Fall 2013
 *
 * Xiannong Meng
 * August 2013
 */

#include "common.h"


/*
 * Print a single record. Assume both parameters are valid.
 *
 * Parameters:
 *   course : the course to be printed
 */
void print_a_record(struct course_info * a_course) {

    printf("    course %s %s\n", a_course->course, a_course->title);
    printf("    professor %s\n", a_course->prof);
    printf("    date and time %s\n", a_course->time);
    printf("    loaction %s\n", a_course->room);
    printf("    credit %3.1f\n", a_course->credit);
    printf("    enrollment %d\n", a_course->enrollment);
}

/*
 * Print the entire list of the course structures.
 *
 * Parameters:
 *    courses :  a list of structures containing course information.
 */
void print_records(struct list * courses) {

  struct course_info * a_course;
  int i = 0;

  printf("--- Course information ---\n");
  a_course = courses->head;
  while (a_course != NULL) { // traverse through the list
    printf("---- course %d ----\n", i++);
    print_a_record(a_course);
    a_course = a_course->next; // move onto next one
  }
}

/*
 * Read a single record from file into the course structure
 */
void read_record(FILE *f, struct course_info ** a_record) {

  int len;
  struct course_info * a_course = *(a_record);
  
  fgets(a_course->title, MAX_STRLEN, f);   // read course title
  len = strlen(a_course->title);
  a_course->title[len-1] = 0;      // terminate the string

  fgets(a_course->prof, MAX_STRLEN, f);    // read professor name
  len = strlen(a_course->prof);
  a_course->prof[len-1] = 0;       // terminate the string

  fgets(a_course->time, WRD_LENGTH, f);    // read time and day of the course
  len = strlen(a_course->time);
  a_course->time[len-1] = 0;       // terminate the string

  // read the room information
  fgets(a_course->room, MAX_STRLEN, f);
  len = strlen(a_course->room);
  a_course->room[len-1] = 0;       // terminate the string

  // read course credit, note the &
  fscanf(f, "%f", &(a_course->credit));    
   
  // read course enrollment, note the &
  fscanf(f, "%d", &(a_course->enrollment));

  fgetc(f); // move over the '\n' char that's left by 'scanf()'
}

/*
 * Read course information from a file and return them as a linked list
 *
 * The format of the input file is as follows
 *  count: an integer indicating how many courses in this file, followed by
 *         the 'count' number of course structures. Each has the following form
 *  course: an 8-char sequence in the form of "CSCI 315"
 *  title:  a variable length string, e.g., "Operating Systems Design"
 *  prof:   a variable length string, e.g., "Professor Meng"
 *  time:   a 16-char string in the form of 'MWF 08:00-09:00'
 *  room:   a variable length string, e.g., "Breakiron 066"
 *  credit: a floating point number for course credit, 1.0, 0.5, 0.25 etc
 *  enrollment: an integer indicating the maximum of students
 *
 * Parameters:
 *   char * fname: name of the file where the information is stored
 * Return:
 *   an array of structures, each of which holds information for one course
 */
struct list * read_data(char * fname) {

  FILE * f = fopen(fname, "r");    // open data file for reading
  int count;    // number of courses
  int i;        // loop index
  int len;      // string length
  struct list * course_list;       // the list holding the courses
  struct course_info * a_course;   // information for one course
  char * course_num = malloc(WRD_LENGTH + 1);

  course_list = (struct list *)malloc(sizeof(struct list));

  fscanf(f, "%d", &count);    // read the number of records
  fgetc(f);

  course_num = fgets(course_num, WRD_LENGTH, f);   // read one course number
  i = 0;

  while (course_num != NULL || strncmp(course_num, "END", 3) == 0) { // more

    len = strlen(course_num);
    course_num[len-1] = 0;         // terminate the string

    a_course = make_node();        // create a course sturcture
    read_record(f, &a_course);     // read the rest of the structure

    strcpy(a_course->course, course_num); // copy course number just read

    // insert the newly read course into the course list
    insert(a_course, &course_list);

    // read next course number
    course_num = fgets(course_num, WRD_LENGTH, f);
    if (course_num == NULL)
      break;
  }

  return course_list;
}

/*
 * Search for a record that contains 'query' in any place.
 *
 * Parameters:
 *    query: the query to search for
 *    courses: the list of courses
 *
 *  Returns:
 *    The pointer to the record containing the query, if found, NULL otherwise.
 */
struct course_info * found(char * query, struct list * courses) {

  struct course_info * a_course;
  int found = FALSE;
  
  a_course = courses->head;
  while (a_course != NULL && found == FALSE) {
    if (strstr(a_course->course, query) != NULL ||
	strstr(a_course->title, query) != NULL ||
	strstr(a_course->prof, query) != NULL ||
	strstr(a_course->room, query) != NULL ||
	strstr(a_course->time, query) != NULL) {
      found = TRUE;
      break;
    }
    a_course = a_course->next;
  }
  if (found == TRUE)
    return a_course;
  else
    return NULL;
}

/*
 * Perform search on the array of the records.
 *
 * Parameters:
 *    courses: the array of course structures
 *    count: the number of records in the array
 */
void do_search(struct list * courses) {

  char query[MAX_STRLEN];
  struct course_info * i;

  printf("Enter a search term as a single word ('END' to quit) : ");
  scanf("%s", query);
  while (strncmp(query, "END", 3) != 0) {
    i = found(query, courses);
    if (i != NULL) {
      printf("record found with match ...\n");
      print_a_record(i);
    } else
      printf("record not found ...\n");
    printf("Enter a search term as a single word ('END' to quit) : ");
    scanf("%s", query);
  }
}

int main(int argc, char* argv[]) {

  // declare an array of dynamic size
  struct list * my_courses;

  printf("reading data\n");

  // read course information from a file
  my_courses = read_data("course-data.txt");
  
  printf("printing data\n");

  // print what we have read
  print_records(my_courses);  

  printf("doing search\n");

  // do search
  do_search(my_courses);

  return 0;
}