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

/* The test file is included into the dd translation unit.
   We can access static globals like conversions_mask and
   the static function synchronize_output(void) directly. */

/* Forward declaration of the target (already defined above in the TU). */
static int synchronize_output (void);

/* Access the conversions_mask and flag bits defined in dd.c. */
extern int conversions_mask;        /* visible within the same TU due to inclusion */

/* Flag values should be visible as macros/enum values. */
/* C_FDATASYNC and C_FSYNC are defined in dd.c's enum. */

/* Helpers for stdout redirection. Avoid Unity assertions while redirected. */

static int save_and_redirect_stdout_to_fd(int target_fd, int *saved_fd_out)
{
    if (!saved_fd_out) return -1;
    int saved = dup(STDOUT_FILENO);
    if (saved < 0) return -1;
    if (dup2(target_fd, STDOUT_FILENO) < 0) {
        close(saved);
        return -1;
    }
    *saved_fd_out = saved;
    return 0;
}

static int redirect_stdout_to_tempfile(int *saved_fd_out)
{
    char tmpl[] = "/tmp/unity_dd_XXXXXX";
    int tmpfd = mkstemp(tmpl);
    if (tmpfd < 0)
        return -1;
    /* Unlink so it is removed automatically after close. */
    unlink(tmpl);

    int rc = save_and_redirect_stdout_to_fd(tmpfd, saved_fd_out);
    /* tmpfd now duplicated to STDOUT_FILENO; close original. */
    close(tmpfd);
    return rc;
}

static int redirect_stdout_to_pipe(int *saved_fd_out, int *pipe_read_end_out)
{
    int fds[2];
    if (pipe(fds) != 0)
        return -1;
    /* fds[1] will be new stdout; keep read end around only to close later. */
    int rc = save_and_redirect_stdout_to_fd(fds[1], saved_fd_out);
    /* Close the original write end fd; STDOUT now refers to it. */
    close(fds[1]);
    if (rc != 0) {
        close(fds[0]);
        return -1;
    }
    if (pipe_read_end_out)
        *pipe_read_end_out = fds[0];
    else
        close(fds[0]);
    return 0;
}

static void restore_stdout(int saved_fd)
{
    if (saved_fd >= 0) {
        dup2(saved_fd, STDOUT_FILENO);
        close(saved_fd);
    }
}

void setUp(void) {
    /* Ensure a known state before each test. */
    conversions_mask = 0;
}

void tearDown(void) {
    /* Restore global state if needed. */
    conversions_mask = 0;
}

static void test_synchronize_output_no_flags_returns_success_and_no_change(void)
{
    conversions_mask = 0;
    int ret = synchronize_output();
    TEST_ASSERT_EQUAL_INT(0, ret);
    TEST_ASSERT_EQUAL_INT(0, conversions_mask);
}

static void test_synchronize_output_fdatasync_success_clears_and_returns_success(void)
{
    /* Redirect stdout to a regular file so fdatasync/fsync succeed. */
    int saved = -1;
    TEST_ASSERT_EQUAL_INT(0, redirect_stdout_to_tempfile(&saved));

    conversions_mask = C_FDATASYNC;
    int ret = synchronize_output();

    restore_stdout(saved);

    TEST_ASSERT_EQUAL_INT(0, ret);
    TEST_ASSERT_EQUAL_INT(0, conversions_mask);
}

static void test_synchronize_output_fsync_success_clears_and_returns_success(void)
{
    int saved = -1;
    TEST_ASSERT_EQUAL_INT(0, redirect_stdout_to_tempfile(&saved));

    conversions_mask = C_FSYNC;
    int ret = synchronize_output();

    restore_stdout(saved);

    TEST_ASSERT_EQUAL_INT(0, ret);
    TEST_ASSERT_EQUAL_INT(0, conversions_mask);
}

static void test_synchronize_output_both_flags_success(void)
{
    int saved = -1;
    TEST_ASSERT_EQUAL_INT(0, redirect_stdout_to_tempfile(&saved));

    conversions_mask = C_FDATASYNC | C_FSYNC;
    int ret = synchronize_output();

    restore_stdout(saved);

    TEST_ASSERT_EQUAL_INT(0, ret);
    TEST_ASSERT_EQUAL_INT(0, conversions_mask);
}

static void test_synchronize_output_fdatasync_on_pipe_triggers_fsync_and_fails(void)
{
    /* On a pipe, fdatasync is expected to fail with EINVAL. The code then
       also tries fsync, which also fails on a pipe -> overall failure. */
    int saved = -1;
    int read_end = -1;
    TEST_ASSERT_EQUAL_INT(0, redirect_stdout_to_pipe(&saved, &read_end));

    conversions_mask = C_FDATASYNC;
    int ret = synchronize_output();

    /* Clean up: restore and close pipe read end. */
    restore_stdout(saved);
    if (read_end >= 0) close(read_end);

    TEST_ASSERT_EQUAL_INT(EXIT_FAILURE, ret);
    TEST_ASSERT_EQUAL_INT(0, conversions_mask);
}

static void test_synchronize_output_fsync_on_pipe_fails(void)
{
    int saved = -1;
    int read_end = -1;
    TEST_ASSERT_EQUAL_INT(0, redirect_stdout_to_pipe(&saved, &read_end));

    conversions_mask = C_FSYNC;
    int ret = synchronize_output();

    restore_stdout(saved);
    if (read_end >= 0) close(read_end);

    TEST_ASSERT_EQUAL_INT(EXIT_FAILURE, ret);
    TEST_ASSERT_EQUAL_INT(0, conversions_mask);
}

int main(void)
{
    UNITY_BEGIN();

    RUN_TEST(test_synchronize_output_no_flags_returns_success_and_no_change);
    RUN_TEST(test_synchronize_output_fdatasync_success_clears_and_returns_success);
    RUN_TEST(test_synchronize_output_fsync_success_clears_and_returns_success);
    RUN_TEST(test_synchronize_output_both_flags_success);
    RUN_TEST(test_synchronize_output_fdatasync_on_pipe_triggers_fsync_and_fails);
    RUN_TEST(test_synchronize_output_fsync_on_pipe_fails);

    return UNITY_END();
}