#include "scope.h"
#include <stdlib.h>
#include <stdio.h>
#include "util.h"
struct scope {
  intern_t *data;
  size_t size;
  size_t capacity;
};

scope_t *scope_alloc(void) {
  scope_t *s = malloc(sizeof(struct scope));
  if (s == NULL)
    die("Out of memory: cannot allocate scope struct");
  s->size = 0;
  s->capacity = 8;
  s->data = malloc(s->capacity * sizeof(intern_t));
  if (s->data == NULL)
    die("Out of memory: cannot allocate scope buffer");
  return s;
}

void scope_push(scope_t *scope, intern_t identifier) {
  if (scope->size == scope->capacity) {
    scope->capacity *= 2;
    scope->data = realloc(scope->data, scope->capacity * sizeof(intern_t));
    if (scope->data == NULL)
      die("Out of memory: cannot enlarge scope array");
  }
  scope->data[scope->size++] = identifier;
}

void scope_pop(scope_t *scope, size_t amount) {
  if (scope->size >= amount)
    scope->size -= amount;
}

void scope_free(scope_t *scope) {
  if (scope == NULL) return;
  free(scope->data);
  free(scope);
}

de_bruijn_t scope_lookup(scope_t *scope, intern_t identifier) {
  for (size_t i = scope->size; i > 0; i--)
    if (scope->data[i - 1] == identifier)
      return (scope->size - i); 
      
  /* caller should decide what happens for "not found" */
  return (de_bruijn_t)-1;
}

void scope_debug_dump(scope_t *scope) {
  for (size_t i = 0; i < scope->size; i++)
    printf("%s, ", scope->data[i]);
  printf("|-");
}