#include "../../unity/unity.h"

#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>

/* The program under test has already included required headers earlier,
   declaring globals like `program_name` and `chown_mode`, as well as
   the enum values CHOWN_CHOWN and CHOWN_CHGRP, and the function usage(). */

static char *read_all_from_fd(int fd, size_t *out_len)
{
    size_t cap = 4096;
    size_t len = 0;
    char *buf = (char *)malloc(cap);
    if (!buf) return NULL;

    for (;;) {
        if (len == cap) {
            size_t ncap = cap * 2;
            char *nbuf = (char *)realloc(buf, ncap);
            if (!nbuf) {
                free(buf);
                return NULL;
            }
            buf = nbuf;
            cap = ncap;
        }
        ssize_t r = read(fd, buf + len, cap - len);
        if (r < 0) {
            if (errno == EINTR) continue;
            free(buf);
            return NULL;
        }
        if (r == 0) break;
        len += (size_t)r;
    }
    /* Null-terminate for convenience; not counted in length */
    if (len == cap) {
        char *nbuf = (char *)realloc(buf, cap + 1);
        if (!nbuf) {
            free(buf);
            return NULL;
        }
        buf = nbuf;
    }
    buf[len] = '\0';
    if (out_len) *out_len = len;
    return buf;
}

/* Helper to run usage(status) in a child and capture stdout/stderr and exit code. */
static void run_usage_and_capture(int status,
                                  int mode_value,
                                  const char *progname,
                                  char **out_stdout, size_t *out_stdout_len,
                                  char **out_stderr, size_t *out_stderr_len,
                                  int *out_exit_code)
{
    int out_pipe[2] = {-1, -1};
    int err_pipe[2] = {-1, -1};
    TEST_ASSERT_EQUAL_INT(0, pipe(out_pipe));
    TEST_ASSERT_EQUAL_INT(0, pipe(err_pipe));

    fflush(stdout);
    fflush(stderr);
    pid_t pid = fork();
    TEST_ASSERT_TRUE_MESSAGE(pid >= 0, "fork failed");

    if (pid == 0) {
        /* Child: set locale and globals; redirect fds; call usage(). */
        /* Avoid using Unity in child. */
        (void)signal(SIGPIPE, SIG_DFL);
        setenv("LC_ALL", "C", 1);
        setenv("LANG", "C", 1);
        setenv("LANGUAGE", "C", 1);

        /* Globals declared by the program headers. */
        extern char const *program_name;
        extern int chown_mode;

        program_name = progname;
        chown_mode = mode_value;

        /* Redirect stdout and stderr. */
        if (dup2(out_pipe[1], STDOUT_FILENO) < 0) _exit(127);
        if (dup2(err_pipe[1], STDERR_FILENO) < 0) _exit(127);

        close(out_pipe[0]);
        close(out_pipe[1]);
        close(err_pipe[0]);
        close(err_pipe[1]);

        /* This will call exit(status). */
        usage(status);

        /* Should not reach here. */
        _exit(126);
    }

    /* Parent: close write ends and read from pipes. */
    close(out_pipe[1]);
    close(err_pipe[1]);

    char *captured_out = read_all_from_fd(out_pipe[0], out_stdout_len);
    char *captured_err = read_all_from_fd(err_pipe[0], out_stderr_len);

    close(out_pipe[0]);
    close(err_pipe[0]);

    int wstatus = 0;
    pid_t w = waitpid(pid, &wstatus, 0);
    TEST_ASSERT_TRUE_MESSAGE(w == pid, "waitpid failed");

    int exit_code = -1;
    if (WIFEXITED(wstatus)) {
        exit_code = WEXITSTATUS(wstatus);
    } else if (WIFSIGNALED(wstatus)) {
        exit_code = 128 + WTERMSIG(wstatus);
    }

    /* Ensure buffers are non-NULL even on failure for easier assertions. */
    if (!captured_out) {
        captured_out = (char *)malloc(1);
        TEST_ASSERT_NOT_NULL(captured_out);
        captured_out[0] = '\0';
        if (out_stdout_len) *out_stdout_len = 0;
    }
    if (!captured_err) {
        captured_err = (char *)malloc(1);
        TEST_ASSERT_NOT_NULL(captured_err);
        captured_err[0] = '\0';
        if (out_stderr_len) *out_stderr_len = 0;
    }

    if (out_stdout) *out_stdout = captured_out; else free(captured_out);
    if (out_stderr) *out_stderr = captured_err; else free(captured_err);
    if (out_exit_code) *out_exit_code = exit_code;
}

void setUp(void) {
    /* No global setup needed. */
}

void tearDown(void) {
    /* No global teardown needed. */
}

static void free_if(char *p) { if (p) free(p); }

/* Test: non-zero status should emit brief help hint on stderr and exit with that status.
   For robustness across gettext, we at least check that "--help" is mentioned and stdout is empty. */
void test_usage_nonzero_status_emits_try_help_to_stderr(void)
{
    char *out = NULL, *err = NULL;
    size_t out_len = 0, err_len = 0;
    int ec = -1;

    run_usage_and_capture(1, CHOWN_CHOWN, "chown",
                          &out, &out_len, &err, &err_len, &ec);

    TEST_ASSERT_EQUAL_INT(1, ec);
    TEST_ASSERT_TRUE_MESSAGE(out_len == 0 || out[0] == '\0', "Expected no stdout for error usage");
    TEST_ASSERT_TRUE_MESSAGE(err_len > 0, "Expected some stderr output");
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(err, "--help"), "Expected '--help' mention in stderr");
    /* Also ensure program name is present in hint */
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(err, "chown"), "Expected program name in stderr");

    free_if(out);
    free_if(err);
}

/* Test: successful usage for chown mode contains key options and examples. */
void test_usage_success_chown_contains_expected_content(void)
{
    char *out = NULL, *err = NULL;
    size_t out_len = 0, err_len = 0;
    int ec = -1;

    run_usage_and_capture(0, CHOWN_CHOWN, "chown",
                          &out, &out_len, &err, &err_len, &ec);

    TEST_ASSERT_EQUAL_INT(0, ec);
    TEST_ASSERT_TRUE_MESSAGE(err_len == 0 || err[0] == '\0', "Expected no stderr for success usage");
    TEST_ASSERT_TRUE_MESSAGE(out_len > 0, "Expected stdout content for success usage");

    /* Check key substrings defined in this source file. */
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "Usage: chown"), "Usage header missing or wrong program name");
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "[OWNER][:[GROUP]]"), "OWNER:GROUP synopsis missing");
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "--reference=RFILE"), "--reference option missing");
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "-h, --no-dereference"), "no-dereference option missing");
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "--from=CURRENT_OWNER:CURRENT_GROUP"), "--from option missing");
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "-R, --recursive"), "recursive option missing");
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "Examples:"), "Examples section missing");
    /* Examples tailored to chown */
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "root:staff /u"), "chown example with group missing");
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "-hR root /u"), "chown recursive example missing");

    free_if(out);
    free_if(err);
}

/* Test: successful usage for chgrp mode contains GROUP-specific text and examples. */
void test_usage_success_chgrp_contains_expected_content(void)
{
    char *out = NULL, *err = NULL;
    size_t out_len = 0, err_len = 0;
    int ec = -1;

    run_usage_and_capture(0, CHOWN_CHGRP, "chgrp",
                          &out, &out_len, &err, &err_len, &ec);

    TEST_ASSERT_EQUAL_INT(0, ec);
    TEST_ASSERT_TRUE_MESSAGE(err_len == 0 || err[0] == '\0', "Expected no stderr for success usage");
    TEST_ASSERT_TRUE_MESSAGE(out_len > 0, "Expected stdout content for success usage");

    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "Usage: chgrp"), "Usage header missing or wrong program name");
    /* Ensure the synopsis reflects GROUP rather than OWNER:GROUP. */
    TEST_ASSERT_NULL_MESSAGE(strstr(out, "[OWNER][:[GROUP]]"), "OWNER:GROUP synopsis should not appear for chgrp");
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "GROUP"), "GROUP synopsis likely missing");

    /* Check some shared options still appear. */
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "--reference=RFILE"), "--reference option missing");
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "-h, --no-dereference"), "no-dereference option missing");
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "-R, --recursive"), "recursive option missing");

    /* Examples tailored to chgrp */
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "staff /u"), "chgrp example with staff missing");
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "-hR staff /u"), "chgrp recursive example missing");

    free_if(out);
    free_if(err);
}

/* Test: ensure dereference-related text appears in help output. */
void test_usage_contains_dereference_options(void)
{
    char *out = NULL, *err = NULL;
    size_t out_len = 0, err_len = 0;
    int ec = -1;

    run_usage_and_capture(0, CHOWN_CHOWN, "chown",
                          &out, &out_len, &err, &err_len, &ec);

    TEST_ASSERT_EQUAL_INT(0, ec);
    TEST_ASSERT_TRUE_MESSAGE(out_len > 0, "Expected stdout content for success usage");
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "--dereference"), "--dereference option missing");
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(out, "-h, --no-dereference"), "no-dereference option missing");

    free_if(out);
    free_if(err);
}

int main(void)
{
    UNITY_BEGIN();
    RUN_TEST(test_usage_nonzero_status_emits_try_help_to_stderr);
    RUN_TEST(test_usage_success_chown_contains_expected_content);
    RUN_TEST(test_usage_success_chgrp_contains_expected_content);
    RUN_TEST(test_usage_contains_dereference_options);
    return UNITY_END();
}