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

/* The test file is included into dd.c, so we can directly access
   internal static variables and the target function ifdatasync(). */

static int make_tempfile(char *tmpl, size_t tmpls)
{
    /* Use a template in /tmp. */
    const char *prefix = "/tmp/dd_ifdatasync_test_XXXXXX";
    size_t need = strlen(prefix) + 1;
    if (tmpls < need) return -1;
    strcpy(tmpl, prefix);
    int fd = mkstemp(tmpl);
    return fd;
}

void setUp(void) {
    /* Ensure process_signals() is safe to run during tests. */
    /* These globals come from dd.c and are visible here due to inclusion. */
    /* Avoid printing transfer stats that might use uninitialized timing. */
    extern int status_level; /* from dd.c */
    extern sigset_t caught_signals; /* from dd.c */
    extern volatile sig_atomic_t interrupt_signal; /* from dd.c */
    extern volatile sig_atomic_t info_signal_count; /* from dd.c */
    extern int progress_len; /* from dd.c */

    status_level = 2; /* STATUS_NOXFER */
    sigemptyset(&caught_signals);
    interrupt_signal = 0;
    info_signal_count = 0;
    progress_len = 0;
}

void tearDown(void) {
    /* Nothing to clean up globally. */
}

/* Test that ifdatasync succeeds (returns 0) on a valid regular file descriptor. */
void test_ifdatasync_valid_fd_returns_zero(void)
{
    char path[128];
    int fd = make_tempfile(path, sizeof(path));
    TEST_ASSERT_TRUE_MESSAGE(fd >= 0, "mkstemp failed to create temp file");

    /* Write some data so there is something to sync. */
    const char *data = "hello";
    ssize_t w = write(fd, data, (size_t)5);
    TEST_ASSERT_TRUE_MESSAGE(w == 5, "write to temp file failed");

    /* Call the target. */
    errno = 0;
    int ret = ifdatasync(fd);

    /* On a regular file with fdatasync available, this should succeed. */
    TEST_ASSERT_EQUAL_INT_MESSAGE(0, ret, "ifdatasync failed on regular file");

    /* Cleanup */
    close(fd);
    unlink(path);
}

/* Test that ifdatasync returns -1 and sets errno to EBADF for an invalid fd. */
void test_ifdatasync_invalid_fd_sets_errno_and_returns_minus1(void)
{
    errno = 0;
    int ret = ifdatasync(-1);
    TEST_ASSERT_EQUAL_INT(-1, ret);
    TEST_ASSERT_EQUAL_INT(EBADF, errno);
}

/* Test that ifdatasync processes pending signals by consuming an info signal. */
void test_ifdatasync_process_signals_consumes_info_signal(void)
{
    /* Prepare a valid fd to ensure fdatasync itself can succeed. */
    char path[128];
    int fd = make_tempfile(path, sizeof(path));
    TEST_ASSERT_TRUE_MESSAGE(fd >= 0, "mkstemp failed to create temp file");

    const char *data = "abc";
    ssize_t w = write(fd, data, (size_t)3);
    TEST_ASSERT_TRUE_MESSAGE(w == 3, "write to temp file failed");

    /* Set a pending info signal and ensure caught_signals is safe. */
    extern volatile sig_atomic_t info_signal_count; /* from dd.c */
    extern sigset_t caught_signals;                 /* from dd.c */
    extern int status_level;                        /* from dd.c */

    sigemptyset(&caught_signals);
    status_level = 2; /* STATUS_NOXFER to avoid print_xfer_stats */

    info_signal_count = 1; /* Simulate an info signal pending */

    errno = 0;
    int ret = ifdatasync(fd);

    TEST_ASSERT_EQUAL_INT(0, ret);
    TEST_ASSERT_EQUAL_INT(0, info_signal_count);

    close(fd);
    unlink(path);
}

int main(void)
{
    UNITY_BEGIN();
    RUN_TEST(test_ifdatasync_valid_fd_returns_zero);
    RUN_TEST(test_ifdatasync_invalid_fd_sets_errno_and_returns_minus1);
    RUN_TEST(test_ifdatasync_process_signals_consumes_info_signal);
    return UNITY_END();
}