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

/* Unity fixtures */
void setUp(void) {
  /* No global setup required */
}
void tearDown(void) {
  /* No global teardown required */
}

/* Helper: create a struct line with optional fields array and optional buffer.
   Note: freeline() frees only line->fields and line->buf.buffer, then delseq
   frees the struct line itself. We therefore avoid allocating per-field beg,
   to prevent leaks not handled by freeline. */
static struct line* make_line_with(size_t nfields, size_t bufsize_bytes)
{
  struct line *ln = (struct line*) malloc(sizeof *ln);
  if (!ln) return NULL;
  memset(ln, 0, sizeof *ln);

  if (nfields > 0) {
    ln->fields = (struct field*) malloc(nfields * sizeof *ln->fields);
    if (!ln->fields) {
      free(ln);
      return NULL;
    }
    /* We do not allocate per-field beg pointers; leave them NULL with len 0. */
    for (size_t i = 0; i < nfields; i++) {
      ln->fields[i].beg = NULL;
      ln->fields[i].len = 0;
    }
    ln->nfields = (idx_t)nfields;
    ln->nfields_allocated = (idx_t)nfields;
  } else {
    ln->fields = NULL;
    ln->nfields = 0;
    ln->nfields_allocated = 0;
  }

  if (bufsize_bytes > 0) {
    ln->buf.buffer = (char*) malloc(bufsize_bytes);
    if (ln->buf.buffer) {
      memset(ln->buf.buffer, 'X', bufsize_bytes);
      ln->buf.length = (idx_t)bufsize_bytes;
    } else {
      ln->buf.buffer = NULL;
      ln->buf.length = 0;
    }
  } else {
    ln->buf.buffer = NULL;
    ln->buf.length = 0;
  }

  return ln;
}

/* Test: delseq on an empty sequence (alloc=0, lines=NULL) should be a no-op */
static void test_delseq_empty_seq(void)
{
  struct seq s;
  s.count = 0;
  s.alloc = 0;
  s.lines = NULL;

  delseq(&s);

  TEST_ASSERT_EQUAL_UINT(0, (unsigned)s.alloc);
  TEST_ASSERT_NULL(s.lines);
}

/* Test: delseq on a lines array populated entirely with NULL entries */
static void test_delseq_null_entries_only(void)
{
  struct seq s;
  s.count = 0;
  s.alloc = 5;
  s.lines = (struct line**) calloc(s.alloc, sizeof *s.lines);
  TEST_ASSERT_NOT_NULL(s.lines);

  void *oldptr = s.lines;
  delseq(&s);

  /* delseq does not modify s.alloc nor s.lines pointer value */
  TEST_ASSERT_EQUAL_UINT(5, (unsigned)s.alloc);
  TEST_ASSERT_EQUAL_PTR(oldptr, s.lines);
}

/* Test: delseq on a sequence with mixed entries (NULL and allocated lines).
   Verifies it safely frees buffers and fields of non-NULL lines. */
static void test_delseq_mixed_entries(void)
{
  struct seq s;
  s.count = 0;
  s.alloc = 4;
  s.lines = (struct line**) malloc(s.alloc * sizeof *s.lines);
  TEST_ASSERT_NOT_NULL(s.lines);

  s.lines[0] = make_line_with(0, 0);     /* No fields, no buffer */
  s.lines[1] = NULL;                      /* NULL entry */
  s.lines[2] = make_line_with(3, 64);     /* Fields array and a buffer */
  s.lines[3] = make_line_with(0, 128);    /* Only buffer */

  TEST_ASSERT_NOT_NULL(s.lines[0]);
  TEST_ASSERT_NULL(s.lines[1]);
  TEST_ASSERT_NOT_NULL(s.lines[2]);
  TEST_ASSERT_NOT_NULL(s.lines[3]);

  void *oldptr = s.lines;
  delseq(&s);

  TEST_ASSERT_EQUAL_UINT(4, (unsigned)s.alloc);
  TEST_ASSERT_EQUAL_PTR(oldptr, s.lines);
}

/* Test: delseq on a larger array to exercise loop bounds and performance */
static void test_delseq_large_array(void)
{
  const size_t N = 1000;
  struct seq s;
  s.count = 0;
  s.alloc = (idx_t)N;
  s.lines = (struct line**) malloc(N * sizeof *s.lines);
  TEST_ASSERT_NOT_NULL(s.lines);

  /* Populate every 10th element; leave others NULL */
  for (size_t i = 0; i < N; i++) {
    if (i % 10 == 0) {
      s.lines[i] = make_line_with(2, 32);
      TEST_ASSERT_NOT_NULL_MESSAGE(s.lines[i], "Allocation failed in setup");
    } else {
      s.lines[i] = NULL;
    }
  }

  void *oldptr = s.lines;
  delseq(&s);

  TEST_ASSERT_EQUAL_UINT(N, (unsigned)s.alloc);
  TEST_ASSERT_EQUAL_PTR(oldptr, s.lines);
}

int main(void)
{
  UNITY_BEGIN();

  RUN_TEST(test_delseq_empty_seq);
  RUN_TEST(test_delseq_null_entries_only);
  RUN_TEST(test_delseq_mixed_entries);
  RUN_TEST(test_delseq_large_array);

  return UNITY_END();
}