/*
 * String wrappers -- src/string.c, TODO.md section 3.1.
 *
 * The two contracts worth testing hardest are the ones that differ from libc:
 * every copying function takes the destination size and treats truncation as an
 * error that writes nothing, and every searching function treats "not found" as
 * a successful answer of NULL.
 */

#include "aksl_capture.h"

#include <errno.h>

/* ---------------------------------------------------------------------- */
/* Length                                                                 */
/* ---------------------------------------------------------------------- */

static int test_strlen_and_strnlen(void)
{
    size_t n = 99;

    AKSL_CHECK_OK(aksl_strlen("hello", &n));
    AKSL_CHECK(n == 5);
    AKSL_CHECK_OK(aksl_strlen("", &n));
    AKSL_CHECK(n == 0);

    /* strnlen stops at maxlen whether or not it found a terminator. */
    AKSL_CHECK_OK(aksl_strnlen("hello", 3, &n));
    AKSL_CHECK(n == 3);
    AKSL_CHECK_OK(aksl_strnlen("hello", 99, &n));
    AKSL_CHECK(n == 5);

    AKSL_CHECK_STATUS(aksl_strlen(NULL, &n), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strlen("x", NULL), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strnlen(NULL, 1, &n), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strnlen("x", 1, NULL), AKERR_NULLPOINTER);
    return 0;
}

/* ---------------------------------------------------------------------- */
/* Copying                                                                */
/* ---------------------------------------------------------------------- */

static int test_strcpy_copies_within_the_buffer(void)
{
    char buf[8];

    AKSL_CHECK_OK(aksl_strcpy(buf, sizeof(buf), "abc"));
    AKSL_CHECK(strcmp(buf, "abc") == 0);

    /* Exactly filling the buffer, terminator included, is not truncation. */
    AKSL_CHECK_OK(aksl_strcpy(buf, sizeof(buf), "1234567"));
    AKSL_CHECK(strcmp(buf, "1234567") == 0);
    return 0;
}

/*
 * The whole point of taking dstsize. akbasic writes this check by hand at ten
 * sites: a length test, then strncpy, then an explicit NUL.
 */
static int test_strcpy_truncation_is_an_error_and_writes_nothing(void)
{
    char buf[8] = "previous";

    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_strcpy(buf, sizeof(buf), "12345678"),
				   AKERR_OUTOFBOUNDS, "destination holds");
    /*
     * Empty, not a truncated prefix. A caller who ignores the status gets
     * nothing, which is far easier to notice than a plausible-looking "1234567".
     */
    AKSL_CHECK(buf[0] == '\0');
    return 0;
}

/*
 * strncpy(3) leaves the destination unterminated when the source is at least n
 * bytes, and NUL-pads the whole remainder when it is shorter. This does neither.
 */
static int test_strncpy_always_terminates_and_never_pads(void)
{
    char buf[16];

    memset(buf, 'Z', sizeof(buf));
    AKSL_CHECK_OK(aksl_strncpy(buf, sizeof(buf), "abcdef", 3));
    AKSL_CHECK(strcmp(buf, "abc") == 0);
    /* Not padded: everything past the terminator is untouched. */
    AKSL_CHECK(buf[4] == 'Z');

    /* n larger than the source just copies the source. */
    AKSL_CHECK_OK(aksl_strncpy(buf, sizeof(buf), "abc", 99));
    AKSL_CHECK(strcmp(buf, "abc") == 0);

    /* n bytes that do not fit the destination is still an error. */
    AKSL_CHECK_STATUS(aksl_strncpy(buf, 4, "abcdef", 6), AKERR_OUTOFBOUNDS);
    AKSL_CHECK(buf[0] == '\0');
    return 0;
}

static int test_strcat_appends_within_the_buffer(void)
{
    char buf[16] = "ab";

    AKSL_CHECK_OK(aksl_strcat(buf, sizeof(buf), "cd"));
    AKSL_CHECK(strcmp(buf, "abcd") == 0);
    AKSL_CHECK_OK(aksl_strcat(buf, sizeof(buf), ""));
    AKSL_CHECK(strcmp(buf, "abcd") == 0);

    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_strcat(buf, sizeof(buf), "0123456789ab"),
				   AKERR_OUTOFBOUNDS, "in use plus");
    /* The existing contents survive a refused append. */
    AKSL_CHECK(strcmp(buf, "abcd") == 0);
    return 0;
}

/* An unterminated destination is refused rather than walked off the end of. */
static int test_strcat_refuses_an_unterminated_destination(void)
{
    char buf[4];

    memset(buf, 'x', sizeof(buf));
    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_strcat(buf, sizeof(buf), "y"),
				   AKERR_VALUE, "not terminated");
    return 0;
}

static int test_strncat_appends_at_most_n(void)
{
    char buf[16] = "ab";

    AKSL_CHECK_OK(aksl_strncat(buf, sizeof(buf), "cdef", 2));
    AKSL_CHECK(strcmp(buf, "abcd") == 0);

    AKSL_CHECK_STATUS(aksl_strncat(buf, 6, "xyz", 3), AKERR_OUTOFBOUNDS);
    AKSL_CHECK(strcmp(buf, "abcd") == 0);
    return 0;
}

static int test_copying_rejects_null_and_zero_size(void)
{
    char buf[8] = "";

    AKSL_CHECK_STATUS(aksl_strcpy(NULL, 8, "x"), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcpy(buf, sizeof(buf), NULL), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcpy(buf, 0, "x"), AKERR_VALUE);
    AKSL_CHECK_STATUS(aksl_strncpy(NULL, 8, "x", 1), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strncpy(buf, sizeof(buf), NULL, 1), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strncpy(buf, 0, "x", 1), AKERR_VALUE);
    AKSL_CHECK_STATUS(aksl_strcat(NULL, 8, "x"), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcat(buf, sizeof(buf), NULL), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcat(buf, 0, "x"), AKERR_VALUE);
    AKSL_CHECK_STATUS(aksl_strncat(NULL, 8, "x", 1), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strncat(buf, sizeof(buf), NULL, 1), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strncat(buf, 0, "x", 1), AKERR_VALUE);
    return 0;
}

/* ---------------------------------------------------------------------- */
/* Duplication                                                            */
/* ---------------------------------------------------------------------- */

static int test_strdup_and_strndup(void)
{
    char *copy = NULL;

    AKSL_CHECK_OK(aksl_strdup("duplicate me", &copy));
    AKSL_CHECK(copy != NULL);
    AKSL_CHECK(strcmp(copy, "duplicate me") == 0);
    AKSL_CHECK_OK(aksl_freep((void **)&copy));
    AKSL_CHECK(copy == NULL);

    AKSL_CHECK_OK(aksl_strndup("duplicate me", 9, &copy));
    AKSL_CHECK(strcmp(copy, "duplicate") == 0);
    AKSL_CHECK_OK(aksl_freep((void **)&copy));

    /* n past the end of the string just copies the string. */
    AKSL_CHECK_OK(aksl_strndup("ab", 99, &copy));
    AKSL_CHECK(strcmp(copy, "ab") == 0);
    AKSL_CHECK_OK(aksl_freep((void **)&copy));

    AKSL_CHECK_STATUS(aksl_strdup(NULL, &copy), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strdup("x", NULL), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strndup(NULL, 1, &copy), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strndup("x", 1, NULL), AKERR_NULLPOINTER);
    return 0;
}

/* ---------------------------------------------------------------------- */
/* Comparison                                                             */
/* ---------------------------------------------------------------------- */

static int test_comparisons(void)
{
    int r = 99;

    AKSL_CHECK_OK(aksl_strcmp("abc", "abc", &r));
    AKSL_CHECK(r == 0);
    AKSL_CHECK_OK(aksl_strcmp("abc", "abd", &r));
    AKSL_CHECK(r < 0);
    AKSL_CHECK_OK(aksl_strcmp("abd", "abc", &r));
    AKSL_CHECK(r > 0);

    AKSL_CHECK_OK(aksl_strncmp("abcXX", "abcYY", 3, &r));
    AKSL_CHECK(r == 0);
    AKSL_CHECK_OK(aksl_strncmp("abcXX", "abcYY", 4, &r));
    AKSL_CHECK(r != 0);

    /* The three case-folding sites akbasic writes out by hand. */
    AKSL_CHECK_OK(aksl_strcasecmp("PRINT", "print", &r));
    AKSL_CHECK(r == 0);
    AKSL_CHECK_OK(aksl_strcasecmp("PRINT", "input", &r));
    AKSL_CHECK(r != 0);
    AKSL_CHECK_OK(aksl_strncasecmp("PRINTXX", "printYY", 5, &r));
    AKSL_CHECK(r == 0);

    AKSL_CHECK_OK(aksl_strcoll("abc", "abc", &r));
    AKSL_CHECK(r == 0);

    AKSL_CHECK_STATUS(aksl_strcmp(NULL, "b", &r), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcmp("a", NULL, &r), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcmp("a", "b", NULL), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strncmp(NULL, "b", 1, &r), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strncmp("a", NULL, 1, &r), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strncmp("a", "b", 1, NULL), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcasecmp(NULL, "b", &r), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcasecmp("a", NULL, &r), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcasecmp("a", "b", NULL), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strncasecmp(NULL, "b", 1, &r), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strncasecmp("a", NULL, 1, &r), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strncasecmp("a", "b", 1, NULL), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcoll(NULL, "b", &r), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcoll("a", NULL, &r), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcoll("a", "b", NULL), AKERR_NULLPOINTER);
    return 0;
}

/* ---------------------------------------------------------------------- */
/* Searching                                                              */
/* ---------------------------------------------------------------------- */

/*
 * Every one of these treats absence as an answer. A library that raised on it
 * would have every caller catching a non-error, and burning a pool slot to do
 * so.
 */
static int test_searching_reports_absence_as_success(void)
{
    const char *s = "the quick brown fox";
    char *at = (char *)0x1;
    size_t n = 99;

    AKSL_CHECK_OK(aksl_strchr(s, 'q', &at));
    AKSL_CHECK(at == s + 4);
    AKSL_CHECK_OK(aksl_strchr(s, 'Z', &at));
    AKSL_CHECK(at == NULL);

    AKSL_CHECK_OK(aksl_strrchr(s, 'o', &at));
    AKSL_CHECK(at == s + 17);
    AKSL_CHECK_OK(aksl_strrchr(s, 'Z', &at));
    AKSL_CHECK(at == NULL);

    AKSL_CHECK_OK(aksl_strstr(s, "brown", &at));
    AKSL_CHECK(at == s + 10);
    AKSL_CHECK_OK(aksl_strstr(s, "purple", &at));
    AKSL_CHECK(at == NULL);

    AKSL_CHECK_OK(aksl_strpbrk(s, "xq", &at));
    AKSL_CHECK(at == s + 4);
    AKSL_CHECK_OK(aksl_strpbrk(s, "ZY", &at));
    AKSL_CHECK(at == NULL);

    AKSL_CHECK_OK(aksl_strspn("aaabbb", "a", &n));
    AKSL_CHECK(n == 3);
    AKSL_CHECK_OK(aksl_strcspn("aaabbb", "b", &n));
    AKSL_CHECK(n == 3);
    return 0;
}

/* The open-coded case-insensitive search, including its edge cases. */
static int test_strcasestr(void)
{
    const char *s = "The Quick Brown Fox";
    char *at = (char *)0x1;

    AKSL_CHECK_OK(aksl_strcasestr(s, "quick", &at));
    AKSL_CHECK(at == s + 4);
    AKSL_CHECK_OK(aksl_strcasestr(s, "QUICK", &at));
    AKSL_CHECK(at == s + 4);
    AKSL_CHECK_OK(aksl_strcasestr(s, "purple", &at));
    AKSL_CHECK(at == NULL);

    /* An empty needle matches at the start, as strstr(3) has it. */
    AKSL_CHECK_OK(aksl_strcasestr(s, "", &at));
    AKSL_CHECK(at == s);

    /* A needle longer than the haystack cannot match, and must not read past. */
    AKSL_CHECK_OK(aksl_strcasestr("ab", "abcdef", &at));
    AKSL_CHECK(at == NULL);

    /* A match right at the end. */
    AKSL_CHECK_OK(aksl_strcasestr(s, "fox", &at));
    AKSL_CHECK(at == s + 16);
    return 0;
}

static int test_searching_rejects_null_arguments(void)
{
    char *at = NULL;
    size_t n = 0;

    AKSL_CHECK_STATUS(aksl_strchr(NULL, 'a', &at), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strchr("a", 'a', NULL), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strrchr(NULL, 'a', &at), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strrchr("a", 'a', NULL), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strstr(NULL, "a", &at), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strstr("a", NULL, &at), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strstr("a", "a", NULL), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcasestr(NULL, "a", &at), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcasestr("a", NULL, &at), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcasestr("a", "a", NULL), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strpbrk(NULL, "a", &at), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strpbrk("a", NULL, &at), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strpbrk("a", "a", NULL), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strspn(NULL, "a", &n), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strspn("a", NULL, &n), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strspn("a", "a", NULL), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcspn(NULL, "a", &n), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcspn("a", NULL, &n), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strcspn("a", "a", NULL), AKERR_NULLPOINTER);
    return 0;
}

/* ---------------------------------------------------------------------- */
/* Tokenising                                                             */
/* ---------------------------------------------------------------------- */

static int test_strtok_r_walks_the_tokens(void)
{
    char input[] = "one,two,,three";
    char *save = NULL;
    char *tok = NULL;
    int seen = 0;

    AKSL_CHECK_OK(aksl_strtok_r(input, ",", &save, &tok));
    AKSL_CHECK(tok != NULL && strcmp(tok, "one") == 0);
    seen++;
    while ( 1 ) {
	AKSL_CHECK_OK(aksl_strtok_r(NULL, ",", &save, &tok));
	if ( tok == NULL ) {
	    break;
	}
	seen++;
    }
    /* strtok_r collapses the empty field between the two commas. */
    AKSL_CHECK(seen == 3);

    AKSL_CHECK_STATUS(aksl_strtok_r(NULL, NULL, &save, &tok), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strtok_r(NULL, ",", NULL, &tok), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strtok_r(NULL, ",", &save, NULL), AKERR_NULLPOINTER);
    return 0;
}

/* strsep keeps the empty fields, which is why it exists alongside strtok_r. */
static int test_strsep_keeps_empty_fields(void)
{
    char input[] = "one,two,,three";
    char *cursor = input;
    char *tok = NULL;
    int seen = 0;

    while ( cursor != NULL ) {
	AKSL_CHECK_OK(aksl_strsep(&cursor, ",", &tok));
	if ( tok == NULL ) {
	    break;
	}
	seen++;
    }
    AKSL_CHECK(seen == 4);

    AKSL_CHECK_STATUS(aksl_strsep(NULL, ",", &tok), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strsep(&cursor, NULL, &tok), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strsep(&cursor, ",", NULL), AKERR_NULLPOINTER);
    return 0;
}

/* ---------------------------------------------------------------------- */
/* Status messages                                                        */
/* ---------------------------------------------------------------------- */

/*
 * aksl_strerror knows this library's own statuses as well as errno values,
 * which is the reason it is not a strerror_r wrapper: strerror_r could never
 * name AKERR_NULLPOINTER.
 */
static int test_strerror_names_both_kinds_of_status(void)
{
    char buf[128];

    AKSL_CHECK_OK(aksl_strerror(ENOENT, buf, sizeof(buf)));
    AKSL_CHECK(buf[0] != '\0');
    AKSL_CHECK(strcmp(buf, "Unknown status 2") != 0);

    AKSL_CHECK_OK(aksl_strerror(AKERR_NULLPOINTER, buf, sizeof(buf)));
    AKSL_CHECK(buf[0] != '\0');

    /* A status nothing has a name for is rendered as its number. */
    AKSL_CHECK_OK(aksl_strerror(-98765, buf, sizeof(buf)));
    AKSL_CHECK(strcmp(buf, "Unknown status -98765") == 0);

    /* Too small a buffer is an error, and leaves nothing rather than a prefix. */
    AKSL_CHECK_STATUS(aksl_strerror(ENOENT, buf, 2), AKERR_OUTOFBOUNDS);
    AKSL_CHECK(buf[0] == '\0');

    AKSL_CHECK_STATUS(aksl_strerror(ENOENT, NULL, 16), AKERR_NULLPOINTER);
    AKSL_CHECK_STATUS(aksl_strerror(ENOENT, buf, 0), AKERR_VALUE);
    return 0;
}

int main(void)
{
    int failures = 0;

    akerr_init();

    AKSL_RUN(failures, test_strlen_and_strnlen);

    AKSL_RUN(failures, test_strcpy_copies_within_the_buffer);
    AKSL_RUN(failures, test_strcpy_truncation_is_an_error_and_writes_nothing);
    AKSL_RUN(failures, test_strncpy_always_terminates_and_never_pads);
    AKSL_RUN(failures, test_strcat_appends_within_the_buffer);
    AKSL_RUN(failures, test_strcat_refuses_an_unterminated_destination);
    AKSL_RUN(failures, test_strncat_appends_at_most_n);
    AKSL_RUN(failures, test_copying_rejects_null_and_zero_size);

    AKSL_RUN(failures, test_strdup_and_strndup);

    AKSL_RUN(failures, test_comparisons);

    AKSL_RUN(failures, test_searching_reports_absence_as_success);
    AKSL_RUN(failures, test_strcasestr);
    AKSL_RUN(failures, test_searching_rejects_null_arguments);

    AKSL_RUN(failures, test_strtok_r_walks_the_tokens);
    AKSL_RUN(failures, test_strsep_keeps_empty_fields);

    AKSL_RUN(failures, test_strerror_names_both_kinds_of_status);

    AKSL_REPORT(failures);
}