#include "../../unity/unity.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <errno.h>
#include <limits.h>
#include <signal.h>

/* External/internal symbols from the program are visible here,
   since this file is included into the same translation unit. */

/* Forward declarations to silence potential warnings (they are defined above). */
static void split_file (void);

/* Test helpers state */
static int start_files_created = 0;
static char test_prefix[64] = {0};

/* Helper: create temp input file with given content and return strdup'ed path */
static char* create_temp_input_file(const char* content) {
  char templ[] = "/tmp/csplit_test_input_XXXXXX";
  int fd = mkstemp(templ);
  if (fd < 0) {
    perror("mkstemp");
    return NULL;
  }
  size_t len = strlen(content);
  if (len > 0) {
    ssize_t w = write(fd, content, len);
    if (w < 0 || (size_t)w != len) {
      close(fd);
      unlink(templ);
      perror("write temp input");
      return NULL;
    }
  }
  if (lseek(fd, 0, SEEK_SET) == (off_t)-1) {
    close(fd);
    unlink(templ);
    perror("lseek");
    return NULL;
  }
  close(fd);
  return strdup(templ);
}

/* Helper: read entire file into newly malloc'd buffer (null-terminated).
   Returns NULL on error. */
static char* read_file_contents(const char* path) {
  struct stat st;
  if (stat(path, &st) != 0)
    return NULL;
  size_t sz = (size_t)st.st_size;
  FILE* f = fopen(path, "rb");
  if (!f)
    return NULL;
  char* buf = (char*)malloc(sz + 1);
  if (!buf) {
    fclose(f);
    return NULL;
  }
  size_t r = fread(buf, 1, sz, f);
  fclose(f);
  if (r != sz) {
    free(buf);
    return NULL;
  }
  buf[sz] = '\0';
  return buf;
}

/* Helper: build filename for file index i using program's make_filename.
   Returns pointer to internal filename_space. */
static const char* outfile_name_for_index(int i) {
  /* make_filename writes into filename_space and returns it */
  return make_filename(i);
}

/* Reset input buffer state and related globals between tests */
static void reset_input_state(void) {
  /* Free any hold area from previous run */
  if (hold_area) {
    free(hold_area);
    hold_area = NULL;
  }
  hold_count = 0;
  have_read_eof = false;
  head = NULL;
  last_line_number = 0;
  current_line = 0;
}

/* Prepare environment before each test call to split_file */
static void prepare_environment(void) {
  /* Ensure signals set is empty for critical sections */
  sigemptyset(&caught_signals);

  /* Avoid printing byte counts to stdout */
  suppress_count = true;

  /* Do not auto-remove files on error or elide empty files in tests */
  remove_files = false;
  elide_empty_files = false;
  suppress_matched = false;

  /* Use numeric suffix with default digits */
  digits = 2;
  suffix = NULL;

  /* Ensure filename_space exists and is large enough */
  if (!filename_space) {
    filename_space = (char*)malloc(1024);
  }

  /* Use a stable test prefix unique(ish) to this process */
  if (test_prefix[0] == '\0') {
    snprintf(test_prefix, sizeof(test_prefix), "utcs_%ld_", (long)getpid());
  }
  prefix = test_prefix;

  /* Reset input stream state */
  reset_input_state();

  /* Start tracking created files from current state */
  start_files_created = files_created;
}

/* Cleanup files created during the test and restore files_created */
static void cleanup_created_files(void) {
  int end = files_created;
  for (int i = start_files_created; i < end; i++) {
    const char* name = outfile_name_for_index(i);
    unlink(name);
  }
  files_created = start_files_created;
}

/* Unity required hooks */
void setUp(void) {
  prepare_environment();
}

void tearDown(void) {
  cleanup_created_files();
}

/* Test 1: Numeric line-count split: single control "3"
   Input: a\nb\nc\nd\ne\n
   Expect: two files:
     00: "a\nb\n"
     01: "c\nd\ne\n"
*/
void test_split_file_linecount_basic(void) {
  const char* input = "a\nb\nc\nd\ne\n";
  char* path = create_temp_input_file(input);
  TEST_ASSERT_NOT_NULL_MESSAGE(path, "Failed to create temp input");

  set_input_file(path);

  /* Build controls: one numeric control lines_required=3 */
  control_used = 0;
  struct control* p = new_control_record();
  p->lines_required = 3; /* split before line 3 */
  p->argnum = 1; /* arbitrary */

  /* Execute */
  split_file();

  /* Verify two files created */
  int created = files_created - start_files_created;
  TEST_ASSERT_EQUAL_INT_MESSAGE(2, created, "Expected exactly 2 output files");

  const char* f0 = outfile_name_for_index(start_files_created + 0);
  const char* f1 = outfile_name_for_index(start_files_created + 1);

  char* c0 = read_file_contents(f0);
  char* c1 = read_file_contents(f1);

  TEST_ASSERT_NOT_NULL_MESSAGE(c0, "Failed to read first output file");
  TEST_ASSERT_NOT_NULL_MESSAGE(c1, "Failed to read second output file");

  TEST_ASSERT_EQUAL_STRING("a\nb\n", c0);
  TEST_ASSERT_EQUAL_STRING("c\nd\ne\n", c1);

  free(c0);
  free(c1);

  unlink(path);
  free(path);
}

/* Test 2: Regexp basic split: control '/^c$/'
   Input: a\nb\nc\nd\ne\n
   Expect: two files:
     00: "a\nb\n"
     01: "c\nd\ne\n"
*/
void test_split_file_regexp_basic(void) {
  const char* input = "a\nb\nc\nd\ne\n";
  char* path = create_temp_input_file(input);
  TEST_ASSERT_NOT_NULL_MESSAGE(path, "Failed to create temp input");

  set_input_file(path);

  /* Build controls: one regexp control '/^c$/' */
  control_used = 0;
  struct control* p = extract_regexp(1, false, "/^c$/");
  (void)p; /* silence unused warning in case */

  /* Execute */
  split_file();

  /* Verify two files created */
  int created = files_created - start_files_created;
  TEST_ASSERT_EQUAL_INT_MESSAGE(2, created, "Expected exactly 2 output files");

  const char* f0 = outfile_name_for_index(start_files_created + 0);
  const char* f1 = outfile_name_for_index(start_files_created + 1);

  char* c0 = read_file_contents(f0);
  char* c1 = read_file_contents(f1);

  TEST_ASSERT_NOT_NULL_MESSAGE(c0, "Failed to read first output file");
  TEST_ASSERT_NOT_NULL_MESSAGE(c1, "Failed to read second output file");

  TEST_ASSERT_EQUAL_STRING("a\nb\n", c0);
  TEST_ASSERT_EQUAL_STRING("c\nd\ne\n", c1);

  free(c0);
  free(c1);

  unlink(path);
  free(path);
}

/* Test 3: Regexp with suppress_matched: '/^c$/'
   suppress_matched = true
   Input: a\nb\nc\nd\ne\n
   Expect: two files:
     00: "a\nb\n"
     01: "d\ne\n"
   (matching line 'c' is suppressed)
*/
void test_split_file_regexp_suppress_matched(void) {
  const char* input = "a\nb\nc\nd\ne\n";
  char* path = create_temp_input_file(input);
  TEST_ASSERT_NOT_NULL_MESSAGE(path, "Failed to create temp input");

  set_input_file(path);

  /* Build controls: one regexp control '/^c$/' */
  control_used = 0;
  struct control* p = extract_regexp(1, false, "/^c$/");
  (void)p;

  /* Suppress matched lines */
  suppress_matched = true;

  /* Execute */
  split_file();

  /* Verify two files created */
  int created = files_created - start_files_created;
  TEST_ASSERT_EQUAL_INT_MESSAGE(2, created, "Expected exactly 2 output files");

  const char* f0 = outfile_name_for_index(start_files_created + 0);
  const char* f1 = outfile_name_for_index(start_files_created + 1);

  char* c0 = read_file_contents(f0);
  char* c1 = read_file_contents(f1);

  TEST_ASSERT_NOT_NULL_MESSAGE(c0, "Failed to read first output file");
  TEST_ASSERT_NOT_NULL_MESSAGE(c1, "Failed to read second output file");

  TEST_ASSERT_EQUAL_STRING("a\nb\n", c0);
  TEST_ASSERT_EQUAL_STRING("d\ne\n", c1);

  free(c0);
  free(c1);

  unlink(path);
  free(path);
}

int main(void) {
  UNITY_BEGIN();
  RUN_TEST(test_split_file_linecount_basic);
  RUN_TEST(test_split_file_regexp_basic);
  RUN_TEST(test_split_file_regexp_suppress_matched);
  return UNITY_END();
}