#include "../../unity/unity.h"
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

/* Unity fixtures */
void setUp(void) {
  /* no-op */
}
void tearDown(void) {
  /* no-op */
}

/* Helper to initialize an empty line object */
static void init_empty_line(struct line* l)
{
  memset(l, 0, sizeof(*l));
}

/* Test: basic append on an empty line should allocate and store the field */
static void test_extract_field_basic_append(void)
{
  struct line l;
  init_empty_line(&l);

  char buf[] = "hello";
  extract_field(&l, buf, (idx_t)5);

  TEST_ASSERT_EQUAL_INT(1, (int)l.nfields);
  TEST_ASSERT_TRUE(l.nfields_allocated >= 1);
  TEST_ASSERT_NOT_NULL(l.fields);
  TEST_ASSERT_EQUAL_PTR(buf, l.fields[0].beg);
  TEST_ASSERT_EQUAL_INT(5, (int)l.fields[0].len);

  /* cleanup */
  freeline(&l);
}

/* Test: multiple appends should grow capacity as needed and preserve entries */
static void test_extract_field_multiple_growth_and_preserve(void)
{
  struct line l;
  init_empty_line(&l);

  enum { N = 50 }; /* enough iterations to ensure multiple growths */
  char storage[N][16];

  for (int i = 0; i < N; ++i)
    {
      /* create distinct content and pointers */
      int n = snprintf(storage[i], sizeof(storage[i]), "f%02d", i);
      if (n < 0) n = 0;
      extract_field(&l, storage[i], (idx_t)n);

      /* After each insertion, verify counters and last entry */
      TEST_ASSERT_EQUAL_INT(i + 1, (int)l.nfields);
      TEST_ASSERT_TRUE(l.nfields_allocated >= l.nfields);
      TEST_ASSERT_EQUAL_PTR(storage[i], l.fields[i].beg);
      TEST_ASSERT_EQUAL_INT(n, (int)l.fields[i].len);

      /* Also spot-check some earlier entries remain intact */
      if (i >= 3)
        {
          TEST_ASSERT_EQUAL_PTR(storage[0], l.fields[0].beg);
          TEST_ASSERT_EQUAL_PTR(storage[1], l.fields[1].beg);
          TEST_ASSERT_EQUAL_PTR(storage[2], l.fields[2].beg);
        }
    }

  /* Verify all entries match after the loop */
  for (int i = 0; i < N; ++i)
    {
      int n = (int)strlen(storage[i]); /* was written by snprintf */
      TEST_ASSERT_EQUAL_PTR(storage[i], l.fields[i].beg);
      TEST_ASSERT_EQUAL_INT(n, (int)l.fields[i].len);
    }

  /* cleanup */
  freeline(&l);
}

/* Test: when there is preallocated capacity, pointer should not change on insert */
static void test_extract_field_no_realloc_when_capacity_available(void)
{
  struct line l;
  init_empty_line(&l);

  /* Preallocate capacity for 8 fields */
  l.nfields_allocated = 8;
  l.fields = (struct field*) malloc(sizeof(struct field) * l.nfields_allocated);
  TEST_ASSERT_NOT_NULL(l.fields);

  struct field* oldptr = l.fields;

  char buf1[] = "A";
  extract_field(&l, buf1, (idx_t)1);

  TEST_ASSERT_EQUAL_PTR(oldptr, l.fields);
  TEST_ASSERT_EQUAL_INT(1, (int)l.nfields);
  TEST_ASSERT_EQUAL_PTR(buf1, l.fields[0].beg);
  TEST_ASSERT_EQUAL_INT(1, (int)l.fields[0].len);

  /* cleanup */
  freeline(&l);
}

/* Test: zero-length field should be recorded and increase count */
static void test_extract_field_zero_length(void)
{
  struct line l;
  init_empty_line(&l);

  char dummy = 'X';
  extract_field(&l, &dummy, (idx_t)0);

  TEST_ASSERT_EQUAL_INT(1, (int)l.nfields);
  TEST_ASSERT_EQUAL_PTR(&dummy, l.fields[0].beg);
  TEST_ASSERT_EQUAL_INT(0, (int)l.fields[0].len);

  /* Add another zero-length to ensure multiple zero-length fields work */
  char dummy2 = 'Y';
  extract_field(&l, &dummy2, (idx_t)0);
  TEST_ASSERT_EQUAL_INT(2, (int)l.nfields);
  TEST_ASSERT_EQUAL_PTR(&dummy2, l.fields[1].beg);
  TEST_ASSERT_EQUAL_INT(0, (int)l.fields[1].len);

  /* cleanup */
  freeline(&l);
}

/* Test: large length value should be stored as-is (no copying performed) */
static void test_extract_field_large_len_value(void)
{
  struct line l;
  init_empty_line(&l);

  char buf[] = "x";
  idx_t large_len = (idx_t)123456; /* arbitrary large length, not used for access */
  extract_field(&l, buf, large_len);

  TEST_ASSERT_EQUAL_INT(1, (int)l.nfields);
  TEST_ASSERT_EQUAL_PTR(buf, l.fields[0].beg);
  TEST_ASSERT_EQUAL_INT((int)large_len, (int)l.fields[0].len);

  /* cleanup */
  freeline(&l);
}

int main(void)
{
  UNITY_BEGIN();
  RUN_TEST(test_extract_field_basic_append);
  RUN_TEST(test_extract_field_multiple_growth_and_preserve);
  RUN_TEST(test_extract_field_no_realloc_when_capacity_available);
  RUN_TEST(test_extract_field_zero_length);
  RUN_TEST(test_extract_field_large_len_value);
  return UNITY_END();
}