#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <string.h>

#include "string_util.h"
#include "ismap.h"


int int_hash_identity(int n);
void free_value(int key, char *value);
void print_entry(int key, char *value);

bool read_segment(FILE *stream, int *id, int *seq, int *tot, char *origin, char *destination);

#define CODE_LENGTH 3

int main(int argc, char **argv)
{
  ismap *routes = ismap_create(int_hash_identity);

  int id, seq, tot;
  char origin[CODE_LENGTH + 1];
  char destination[CODE_LENGTH + 1];
  while (read_segment(stdin, &id, &seq, &tot, origin, destination))
    {
      if (!ismap_contains_key(routes, id))
	{
	  // key is not present; add it with empty route of
	  // approriate size (3 chars for each airport in the route);
	  char *route = malloc(sizeof(char) * CODE_LENGTH * (tot + 1) + 1);
	  for (int i = 0; i < CODE_LENGTH * (tot + 1); i++)
	    {
	      route[i] = ' ';
	    }
	  route[CODE_LENGTH * (tot + 1)] = '\0';

	  ismap_put(routes, id, route);
	}
      
      // key should be present now; get value and update it
      char *route = ismap_get(routes, id);
      
      if (route != NULL)
	{
	  // make sure sequence numbers work out
	  if (strlen(route) >= (tot + 1) * CODE_LENGTH)
	    {
	      // copy origin and destination airports into appropriate
	      // location in route
	      strncpy(route + (seq - 1) * CODE_LENGTH, origin, CODE_LENGTH);
	      strncpy(route + seq * CODE_LENGTH, destination, CODE_LENGTH);
	    }
	}
    }

  ismap_for_each(routes, print_entry);

  // free allocated memory
  ismap_for_each(routes, free_value);
  ismap_destroy(routes);
}

/**
 * Prints the given map entry to standard output.
 */
void print_entry(int key, char *value)
{
  printf("%d=%s\n", key, value);
}

/**
 * Frees the value in the given map entry.
 */
void free_value(int key, char *value)
{
  free(value);
}

/**
 * A very bad hash function for integers.
 */
int int_hash_identity(int n)
{
  return n;
}

/**
 * Reads a record from the US DOT coupons database into the given
 * (simulated) reference parameters.
 *
 * @param stream the stream to read from
 * @param id a pointer to an int, non-NULL
 * @param tot a pointer to an int, non-NULL
 * @param seq a pointer to an int, non-NULL
 * @param origin a pointer to an array of 4 characters, non-NULL
 * @param destination a pointer to an array of 4 characters, non-NULL
 */
bool read_segment(FILE *stream, int *id, int *seq, int *tot, char *origin, char *destination)
{
  // zero everything out so we can check later if they were read correctly
  *id = 0;
  *seq = 0;
  *tot = 0;
  origin[0] = '\0';
  destination[0] = '\0';

  // no line in the database is > 80 characters, but use read_line to be safe
  char line[81];
  read_line(line, 80);

  // check that we read enough to at least get the id
  int len = strlen(line);
  
  if (strlen(line) > 2)
    {
      // skip the 1st two digits in the id (they're always 20 in our data)
      // (if we want all the digits then we need to use a long for the ids
      // and hence our map need to work with longs as keys)
      *id = atoi(line + 2);

      // look for spaces in the input, and pluck out the parts before
      // the 2nd, 3rd, 5th, and 6th spaces, which are the sequence number,
      // number of records in the sequence, origin, and destination
      // respectively
      int space = 0;
      char *last = line;
      for (int i = 0; i < len; i++)
	{
	  if (line[i] == ' ')
	    {
	      // found a space...count it and replace with a null character
	      // so we can treat from after the last space to here as a string
	      space++;
	      line[i] = '\0';
	      if (space == 2)
		{
		  *seq = atoi(last);
		}
	      else if (space == 3)
		{
		  *tot = atoi(last);
		}
	      else if (space == 5)
		{
		  if (strlen(last) == CODE_LENGTH)
		    {
		      strcpy(origin, last);
		    }
		}
	      else if (space == 6)
		{
		  if (strlen(last) == CODE_LENGTH)
		    {
		      strcpy(destination, last);
		    }
		}

	      // remember location of this space to use as the beginning
	      // of the string ended by the next space we found
	      last = line + i + 1;
	    }
	}
    }

  // return true if we were able to read everything
  return (*id != 0 && *seq != 0 && *tot != 0 && strlen(origin) > 0 && strlen(destination) > 0);
}