#include "buff.h"

line_t* __search_pos(int addr){
  
  int i;
  line_t *cur = b_start;
  for(i=1; i<addr; i++){
    cur = cur -> next;
  }
  return cur;
}

int read_lines(FILE *fin){
  
  char buff[4096];
  line_t *line;
  size_t s;

  while(feof(fin) == 0){
    if (!fgets(buff, 4095, fin)) break;
    s = strlen(buff) + 1;
    line = malloc(sizeof(line_t));
    line->s = s;
    line->c = malloc(s * sizeof(char));
    memcpy(line->c, buff, s);
    line->next = NULL;
    
    if (b_start == NULL){
      line->prev = NULL;
      b_start = line;
    }
    else{
      b_end->next = line;
      line->prev = b_end;
    }
    b_end = line;
    num += 1;
  }
  cur = b_end;
  pos = num;
}

void print_cur_line(char lineno){
  
  if (!b_start){
    printf("?\n");
    return;
  }
  
  if (lineno)
    printf("%d\t", pos);
  printf("%s", cur->c);
}
  
void print_lines(char lineno){

  line_t *p;
  int i=0;
  p = b_start;

  
  printf(">>> *** addr1: %d addr2: %d ***\n", addr1, addr2);
  for (i=1; i<addr2; i++) p = p->next;
  pos = i;
  cur = p;
  while(pos < addr1){
    if (lineno)
      printf("%d\t", pos);
    printf("%s", cur->c);
    cur = cur->next;
    pos += 1;
  }
  if (lineno)
    printf("%d\t", pos);
  printf("%s", cur->c);
  if (pos != num) {
    pos += 1;
    cur = cur -> next;
  }
}

int move_to_line(int addr, char print){

  if (addr > num)
    return -1;
  else if (addr >= 0){
    pos = addr;
    cur = __search_pos(pos);
    if (print)
      print_cur_line(0);
  }
  return pos;
}

void print_lineno(){
  printf("%d\n", addr1);
}

int move_forward(int n){

  if (pos + n > num){
    printf("?\n");
    return -1;
  }
  while(n-- >0){
    cur = cur->next;
  }
  pos += n;
  return 0;
}

int move_backward(int n){

  if (pos - n < 1){
    printf("?\n");
    return -1;
  }
  while(n-- >0){
    cur = cur->prev;
  }
  pos -= n;
  return 0;
}



/* add lines after pos */
void append_lines(){

  char buff[4096];
  int n,s;
  line_t *first, *l, *last;
  
  n = 0;
  first = last = NULL;
  while(feof(stdin) == 0){
    if (!fgets(buff, 4095, stdin)) break;
    if (buff[0] == '.')
      break;
    s = strlen(buff) + 1;
    l = malloc(sizeof(line_t));
    l->c = malloc(s * sizeof(char));
    memcpy(l->c, buff, s);
    l->s = s;
    if (first == NULL)
      first = last = l;
    else{
      last -> next = l;
      l->prev = last;
      last = l;
    }
    n += 1;
  }
  if (addr1 == 0){
    last->next = b_start;
    b_start -> prev = last;
    b_start = first;
    move_to_line(n,0);
  }
  else{
    last -> next = cur -> next;
    cur->next = first;
    first->prev = cur;
    move_forward(n);
  }
}

void insert_lines(){}

void delete_lines(){}