/*
 * Paul Heidelman
 * Case Western Reserve University
 * EECS 337 Fall 2009
 * Homework 1
 * Modified for Homework 2
 */

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


typedef struct list_entry list_entry_t;

struct list_entry {
	void *key;
	void *value;
	list_entry_t *next;
};

typedef struct {
	list_entry_t *list;
	int (*cmp)(const void *, const void *); /* Comparison function */
} list_head_t;


list_head_t *list_init(int (*cmp)(const void *, const void *)){
	//assign cmp
	list_head_t *n;
	n = (list_head_t *) malloc(sizeof(list_head_t));
	if(n == NULL)
	{
		fprintf(stderr, "Error creating list_head_t\n");
		return NULL;
	}
	n->cmp = cmp;
	return n;
};

list_entry_t *list_insert(list_head_t *head, void *key, void *value){
	if(head == NULL)
	{
		fprintf(stderr, "Invalid list_head_t\n");
		return NULL;
	}
	if(key == NULL)
	{
		fprintf(stderr, "Invalid key\n");
		return NULL;
	}
	if(value == NULL)
	{
		fprintf(stderr, "List is empty!\n");
		return NULL;
	}

	list_entry_t *new_entry;
	new_entry = (list_entry_t *) malloc(sizeof(list_entry_t));
	new_entry->key = key;
	new_entry->value = value;
	list_entry_t *n;
	n = (list_entry_t *) malloc(sizeof(list_entry_t));

	if(head->list == NULL)
	{//then the list is empty, so add a first entry
		//printf("new");
		head->list = new_entry;
	}
	else
	{
		//printf("adding");
		n = head->list;
		while(n->next != NULL)
			n = n->next;
		n->next = new_entry;
	}
	return new_entry;
};

void *list_search(list_head_t *head, void *key){
	if(head == NULL)
	{
		fprintf(stderr, "Invalid list_head_t\n");
		return NULL;
	}
	if(key == NULL)
	{
		fprintf(stderr, "Invalid key\n");
		return NULL;
	}
	if(head->list == NULL)
	{
		fprintf(stderr, "List is empty!\n");
		return NULL;
	}

	list_entry_t *n;
	n = head->list;
	while(n != NULL)
	{
		//printf("not %ld\n",n->value);
		if(head->cmp(n->key, key) == 0)
			return n->value;
		else
		n = n->next;
	}
	return NULL;
};

void list_delete(list_head_t *head){
	assert(head != NULL);
	list_entry_t *temp1;
	temp1 = (list_entry_t *) malloc(sizeof(list_entry_t));
	temp1 = head->list;
	while (temp1 != NULL)
	{
		list_entry_t *temp2; 
		temp2 = (list_entry_t *) malloc(sizeof(list_entry_t));
		temp2 = temp1->next;
		free(temp1);
		temp1 = temp2;
	}
/*
	list_entry_t *o;
	o = (list_entry_t *) malloc(sizeof(list_entry_t));
	list_entry_t *p;
	p = (list_entry_t *) malloc(sizeof(list_entry_t));
	o = head->list;
	free(head);
	while(o != NULL)
	{
		//list_entry_t *p = n->next;
		p = o->next;
		free(o);
		o = p;
	}
	free(p);
*/
	return;
};

int cmp_double(double *a, double *b){
	if(*a == *b)
		return 0;
	else
		return 1;
};

int cmp_string(const void *a, const void *b){
	assert(a != NULL);
	assert(b != NULL);
	return strcmp(a, b);
};

int main(){

	/*
	insert(1,2)
	insert(3,4)
	insert(5,6)
	search(1)
	search(3)
	search(5)
	insert(3,7)
	search(8)
	search(3)
	*/

	printf("Creating double_list...\n");
	list_head_t *double_list;
	double_list = list_init(cmp_double);

	double a = 1;
	double b = 2;
	list_insert(double_list, &a, &b);
	
	double c = 3;
	double d = 4;
	list_insert(double_list, &c, &d);
	
	double e = 5;
	double f = 6;
	list_insert(double_list, &e, &f);

	double s = 1;
	double *result;
	result = list_search(double_list, &s);
	if(result != NULL)
		printf("found: %lf\n", *result);
	
	else
		printf("not found\n");

	s = 3;
	result = list_search(double_list, &s);
	if(result != NULL)
		printf("found: %lf\n", *result);
	
	else
		printf("not found\n");

	s = 5;
	result = list_search(double_list, &s);
	if(result != NULL)
		printf("found: %lf\n", *result);
	
	else
		printf("not found\n");

	double g = 3;
	double h = 7;
	list_insert(double_list, &g, &h);

	s = 8;
	result = list_search(double_list, &s);
	if(result != NULL)
		printf("found: %lf\n", *result);
	
	else
		printf("not found\n");

	
	s = 3;
	result = list_search(double_list, &s);
	if(result != NULL)
		printf("found: %lf\n", *result);
	
	else
		printf("not found\n");

	list_delete(double_list);



	/*
	 *insert("one",2)
	 *insert(two",4)
	 *insert(three,6)
	 *search(one)
	 *search(three)
	 *search(five)
	 *insert(three,7)
	 *search(eight)
	 *search(three)
	 */

	printf("\n\nCreating string_list...\n");
	list_head_t *string_list;
	string_list = list_init(cmp_string);

	char str1[] = "one";
	double dbl1 = 2;
	list_insert(string_list, &str1, &dbl1);

	char str2[] = "two";
	double dbl2 = 4;
	list_insert(string_list, &str2, &dbl2);

	char str3[] = "three";
	double dbl3 = 6;
	list_insert(string_list, &str3, &dbl3);

	char search_str[] = "one";
	result = list_search(string_list, &search_str);
	if(result != NULL)
		printf("found: %lf\n", *result);
	
	else
		printf("not found\n");

	strcpy(search_str, "three");
	result = list_search(string_list, &search_str);
	if(result != NULL)
		printf("found: %lf\n", *result);
	
	else
		printf("not found\n");

	strcpy(search_str, "five");
	result = list_search(string_list, &search_str);
	if(result != NULL)
		printf("found: %lf\n", *result);
	
	else
		printf("not found\n");

	char str4[] = "three";
	double dbl4 = 7;
	list_insert(string_list, &str4, &dbl4);

	strcpy(search_str, "eight");
	result = list_search(string_list, &search_str);
	if(result != NULL)
		printf("found: %lf\n", *result);
	
	else
		printf("not found\n");

	strcpy(search_str, "three");
	result = list_search(string_list, &search_str);
	if(result != NULL)
		printf("found: %lf\n", *result);
	
	else
		printf("not found\n");


	list_delete(string_list);
	return 0;
};