#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include <limits.h>
#include "LinkedList.h"

LinkedList *newLL() {
  Element *e = NULL;
  LinkedList *l = malloc(sizeof(LinkedList));
  assert(l != NULL);

  // In the list, we add two markers which will simplify add and
  // remove algorithms
  e = malloc(sizeof(Element));
  assert(e != NULL);
  e->val = INT_MIN;
  pthread_mutex_init(&(e->mutex),NULL);
  l->first = e;

  e = malloc(sizeof(Element));
  assert(e != NULL);
  pthread_mutex_init(&(e->mutex),NULL);
  e->val = INT_MAX;
  l->first->next = e;
  l->first->next->next = NULL;

  return l;
}

void dumpLL(LinkedList *l) {
  Element *e = l->first->next;

  printf("Begin dump LinkedList %p\n", l);
  MUTEX_LOCK(e->mutex);
  while (e->val != INT_MAX) {
    printf("  val = %8d\n", e->val);
    MUTEX_LOCK(e->next->mutex);
    MUTEX_UNLOCK(e->mutex);
    e = e->next;
  }
  MUTEX_UNLOCK(e->mutex);
  printf("End   dump LinkedList %p\n", l);
}

int sizeLL(LinkedList *l) {
  Element *e = l->first->next;
  int nb = 0;

  MUTEX_LOCK(e->mutex);
  while (e->val != INT_MAX) {
    ++nb;
    MUTEX_LOCK(e->next->mutex);
    MUTEX_UNLOCK(e->mutex);
    e = e->next;
  }
  MUTEX_UNLOCK(e->mutex);

  return nb;
}

void freeLL(LinkedList *l) {
  Element *e = l->first;

  // We free all the elements inside the list
  do {
    Element *nextE = e->next;
    int rc = pthread_mutex_destroy(&(e->mutex));
    assert(rc == 0);
    free(e);
    e = nextE;
  } while (e != NULL);

  // We free the LinkedList itself
  free(l);
} 

void addLL(LinkedList *l, int v) {
  Element *e = l->first;
  Element *newE = NULL;

  assert(v != INT_MIN && v!= INT_MAX);

  MUTEX_LOCK(e->mutex);
  MUTEX_LOCK(e->next->mutex);
  // We look where to insert our value
  while (v > e->next->val) {
    Element *nextE = e->next;
    MUTEX_LOCK(nextE->next->mutex);
    MUTEX_UNLOCK(e->mutex);
    e = nextE;
  }

  // We insert the new element in the list between e and e->next
  newE = malloc(sizeof(Element));
  assert(newE != NULL);
  newE->val = v;
  newE->next = e->next;
  pthread_mutex_init(&(newE->mutex),NULL);
  e->next = newE;
  MUTEX_UNLOCK(newE->next->mutex);
  MUTEX_UNLOCK(e->mutex);
} 

void removeLL(LinkedList *l, int v) {
  Element *e = l->first;

  assert(v != INT_MIN && v!= INT_MAX);

  MUTEX_LOCK(e->mutex);
  MUTEX_LOCK(e->next->mutex);
  // We look for the value to suppress
  while (v > e->next->val) {
    Element *nextE = e->next;
    MUTEX_LOCK(nextE->next->mutex);
    MUTEX_UNLOCK(e->mutex);
    e = nextE;
  }

  if (v == e->next->val) {
    // The value we need to remove is contained in e->next
    Element *eToRemove = e->next;
    int rc;
    e->next = eToRemove->next;
    eToRemove->next = NULL;
    MUTEX_UNLOCK(eToRemove->mutex);
    rc = pthread_mutex_destroy(&(eToRemove->mutex));
    assert(rc == 0);
    free(eToRemove);
    MUTEX_UNLOCK(e->mutex);    
  } else {
    fprintf(stderr, "WARNING : value %d not found in list %p\n", v, l);
  }
}