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

/* Globals from the program (accessible since this file is included into the TU):
   - struct mode_change *change;
   - mode_t umask_value;
   - bool recurse;
   - int dereference;
   - bool force_silent;
   - bool diagnose_surprises;
   - enum Verbosity verbosity;
   - Functions: mode_compile, xfts_open, fts_read, fts_set, fts_close, process_file
*/

static mode_t saved_umask;

/* Utility: create a temporary directory, return malloc'd path */
static char* make_temp_dir(void)
{
    char tmpl[] = "/tmp/chmod_ut_XXXXXX";
    char *path = malloc(sizeof(tmpl));
    if (!path) return NULL;
    memcpy(path, tmpl, sizeof(tmpl));
    if (!mkdtemp(path))
    {
        free(path);
        return NULL;
    }
    return path;
}

/* Utility: join dir and name into a newly malloc'd path */
static char* path_join(const char* dir, const char* name)
{
    size_t ld = strlen(dir), ln = strlen(name);
    size_t need = ld + 1 + ln + 1;
    char *res = malloc(need);
    if (!res) return NULL;
    memcpy(res, dir, ld);
    res[ld] = '/';
    memcpy(res + ld + 1, name, ln);
    res[ld + 1 + ln] = '\0';
    return res;
}

/* Utility: create a regular file with specified mode, returns 0 on success */
static int create_file_with_mode(const char* path, mode_t mode)
{
    int fd = open(path, O_CREAT | O_TRUNC | O_WRONLY, mode);
    if (fd < 0) return -1;
    if (close(fd) != 0) return -1;
    /* Ensure exact mode (umask 0 in setUp, but call chmod just in case) */
    if (chmod(path, mode) != 0) return -1;
    return 0;
}

/* Utility: create symlink */
static int create_symlink_to(const char* target, const char* linkpath)
{
    /* Remove pre-existing */
    unlink(linkpath);
    return symlink(target, linkpath);
}

/* Utility: stat mode of a path (referent) */
static mode_t get_mode_stat(const char* path)
{
    struct stat st;
    if (stat(path, &st) != 0) return (mode_t)~0;
    return st.st_mode;
}

/* Utility: lstat mode of a path (symlink itself) */
static mode_t get_mode_lstat(const char* path)
{
    struct stat st;
    if (lstat(path, &st) != 0) return (mode_t)~0;
    return st.st_mode;
}

/* Utility: open xfts for a single path and return first entry */
static FTSENT* open_single_fts(const char* path, FTS **out_fts, int flags)
{
    char *paths[2];
    paths[0] = (char*)path;
    paths[1] = NULL;
    FTS *fts = xfts_open(paths, flags, NULL);
    if (!fts)
    {
        *out_fts = NULL;
        return NULL;
    }
    FTSENT *ent = fts_read(fts);
    *out_fts = fts;
    return ent;
}

void setUp(void) {
    /* Ensure environment messages are English for stable assertions */
    setenv("LC_ALL", "C", 1);
    setenv("LANG", "C", 1);
    /* Make umask predictable */
    saved_umask = umask(0);
    umask_value = 0;

    /* Defaults for globals used by process_file */
    recurse = false;
    dereference = -1; /* default */
    force_silent = false;
    diagnose_surprises = false;
    verbosity = V_off;
}

void tearDown(void) {
    /* Restore process umask */
    umask(saved_umask);
}

/* Test 1: Regular file mode change should succeed and set execute for user */
void test_process_file_regular_add_exec(void)
{
    char *dir = make_temp_dir();
    TEST_ASSERT_NOT_NULL(dir);

    char *file = path_join(dir, "f1");
    TEST_ASSERT_NOT_NULL(file);

    TEST_ASSERT_EQUAL_INT(0, create_file_with_mode(file, 0644));

    /* Prepare change: add u+x */
    change = mode_compile("u+x", 0);

    FTS *fts = NULL;
    FTSENT *ent = open_single_fts(file, &fts, FTS_PHYSICAL);
    TEST_ASSERT_NOT_NULL_MESSAGE(ent, "fts_read should return an entry for the file");
    TEST_ASSERT_NOT_NULL(fts);

    bool ok = process_file(fts, ent);
    /* Close FTS before assertions further to avoid side effects */
    TEST_ASSERT_EQUAL_INT(0, fts_close(fts));
    TEST_ASSERT_TRUE(ok);

    mode_t m = get_mode_stat(file);
    TEST_ASSERT_NOT_EQUAL((mode_t)~0, m);
    TEST_ASSERT_TRUE(m & S_IXUSR);

    unlink(file);
    rmdir(dir);
    free(file);
    free(dir);
}

/* Test 2: Symlink with no-dereference should not change referent */
void test_process_file_symlink_no_deref_noop(void)
{
    char *dir = make_temp_dir();
    TEST_ASSERT_NOT_NULL(dir);

    char *tgt = path_join(dir, "target");
    char *lnk = path_join(dir, "link");
    TEST_ASSERT_NOT_NULL(tgt);
    TEST_ASSERT_NOT_NULL(lnk);

    TEST_ASSERT_EQUAL_INT(0, create_file_with_mode(tgt, 0644));
    TEST_ASSERT_EQUAL_INT(0, create_symlink_to(tgt, lnk));

    mode_t before = get_mode_stat(tgt);
    TEST_ASSERT_NOT_EQUAL((mode_t)~0, before);

    /* change: a+x, but do not dereference symlinks */
    change = mode_compile("a+x", 0);
    dereference = 0; /* --no-dereference */

    FTS *fts = NULL;
    FTSENT *ent = open_single_fts(lnk, &fts, FTS_PHYSICAL);
    TEST_ASSERT_NOT_NULL(ent);
    TEST_ASSERT_NOT_NULL(fts);

    bool ok = process_file(fts, ent);
    TEST_ASSERT_EQUAL_INT(0, fts_close(fts));
    TEST_ASSERT_TRUE(ok);

    mode_t after = get_mode_stat(tgt);
    TEST_ASSERT_NOT_EQUAL((mode_t)~0, after);
    TEST_ASSERT_EQUAL_HEX32(before & 07777, after & 07777);

    unlink(lnk);
    unlink(tgt);
    rmdir(dir);
    free(lnk);
    free(tgt);
    free(dir);
}

/* Test 3: Symlink with dereference should change the referent */
void test_process_file_symlink_with_deref_changes_target(void)
{
    char *dir = make_temp_dir();
    TEST_ASSERT_NOT_NULL(dir);

    char *tgt = path_join(dir, "target2");
    char *lnk = path_join(dir, "link2");
    TEST_ASSERT_NOT_NULL(tgt);
    TEST_ASSERT_NOT_NULL(lnk);

    TEST_ASSERT_EQUAL_INT(0, create_file_with_mode(tgt, 0644));
    TEST_ASSERT_EQUAL_INT(0, create_symlink_to(tgt, lnk));

    change = mode_compile("a+x", 0);
    dereference = 1; /* --dereference */
    verbosity = V_off;

    FTS *fts = NULL;
    FTSENT *ent = open_single_fts(lnk, &fts, FTS_PHYSICAL);
    TEST_ASSERT_NOT_NULL(ent);
    TEST_ASSERT_NOT_NULL(fts);

    bool ok = process_file(fts, ent);
    TEST_ASSERT_EQUAL_INT(0, fts_close(fts));
    TEST_ASSERT_TRUE(ok);

    mode_t m = get_mode_stat(tgt);
    TEST_ASSERT_NOT_EQUAL((mode_t)~0, m);
    TEST_ASSERT_TRUE(m & S_IXUSR);

    unlink(lnk);
    unlink(tgt);
    rmdir(dir);
    free(lnk);
    free(tgt);
    free(dir);
}

/* Test 4: No-op change when mode already has requested bits */
void test_process_file_no_change_needed(void)
{
    char *dir = make_temp_dir();
    TEST_ASSERT_NOT_NULL(dir);

    char *file = path_join(dir, "already_exec");
    TEST_ASSERT_NOT_NULL(file);

    TEST_ASSERT_EQUAL_INT(0, create_file_with_mode(file, 0755));
    mode_t before = get_mode_stat(file);
    TEST_ASSERT_NOT_EQUAL((mode_t)~0, before);

    change = mode_compile("u+x", 0);
    verbosity = V_off;

    FTS *fts = NULL;
    FTSENT *ent = open_single_fts(file, &fts, FTS_PHYSICAL);
    TEST_ASSERT_NOT_NULL(ent);
    TEST_ASSERT_NOT_NULL(fts);

    bool ok = process_file(fts, ent);
    TEST_ASSERT_EQUAL_INT(0, fts_close(fts));
    TEST_ASSERT_TRUE(ok);

    mode_t after = get_mode_stat(file);
    TEST_ASSERT_NOT_EQUAL((mode_t)~0, after);
    TEST_ASSERT_EQUAL_HEX32(before & 07777, after & 07777);

    unlink(file);
    rmdir(dir);
    free(file);
    free(dir);
}

/* Test 5: Verbosity high prints a diagnostic for a change */
void test_process_file_verbose_outputs_message(void)
{
    char *dir = make_temp_dir();
    TEST_ASSERT_NOT_NULL(dir);

    char *file = path_join(dir, "verbose_file");
    TEST_ASSERT_NOT_NULL(file);

    TEST_ASSERT_EQUAL_INT(0, create_file_with_mode(file, 0644));

    change = mode_compile("u+x", 0);
    verbosity = V_high;

    /* Setup stdout capture */
    int saved_stdout = dup(STDOUT_FILENO);
    TEST_ASSERT_MESSAGE(saved_stdout >= 0, "dup stdout failed");

    int pipefd[2];
    TEST_ASSERT_EQUAL_INT_MESSAGE(0, pipe(pipefd), "pipe failed");

    fflush(stdout);
    if (dup2(pipefd[1], STDOUT_FILENO) < 0) {
        /* Restore and fail */
        dup2(saved_stdout, STDOUT_FILENO);
        close(saved_stdout);
        close(pipefd[0]); close(pipefd[1]);
        TEST_FAIL_MESSAGE("dup2 failed to redirect stdout");
    }

    FTS *fts = NULL;
    FTSENT *ent = open_single_fts(file, &fts, FTS_PHYSICAL);
    TEST_ASSERT_NOT_NULL(ent);
    TEST_ASSERT_NOT_NULL(fts);

    /* Call target while stdout is redirected.
       Do not use Unity asserts here. */
    bool ok_call = process_file(fts, ent);
    ignore_value(fts_close(fts)); /* Close FTS even if we don't assert now */
    fflush(stdout);

    /* Restore stdout */
    dup2(saved_stdout, STDOUT_FILENO);
    close(saved_stdout);
    close(pipefd[1]);

    /* Now safe to assert */
    TEST_ASSERT_TRUE(ok_call);

    char buf[1024];
    ssize_t n = read(pipefd[0], buf, sizeof(buf) - 1);
    close(pipefd[0]);
    TEST_ASSERT_TRUE_MESSAGE(n > 0, "no output captured");
    if (n > 0) buf[n] = '\0'; else buf[0] = '\0';

    /* Expect message like: "mode of <file> changed from ..." */
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(buf, "mode of"), "Verbose output missing 'mode of'");
    TEST_ASSERT_NOT_NULL_MESSAGE(strstr(buf, "changed"), "Verbose output missing 'changed'");

    unlink(file);
    rmdir(dir);
    free(file);
    free(dir);
}

int main(void)
{
    UNITY_BEGIN();
    RUN_TEST(test_process_file_regular_add_exec);
    RUN_TEST(test_process_file_symlink_no_deref_noop);
    RUN_TEST(test_process_file_symlink_with_deref_changes_target);
    RUN_TEST(test_process_file_no_change_needed);
    RUN_TEST(test_process_file_verbose_outputs_message);
    return UNITY_END();
}