#include "carp_utf8.h"

String String_allocate(int len, char byte) {
    /* Allocate a string of length 'len + 1'
     * setting the first len bytes to byte
     * and adding a null terminator
     *
     * String_alloc(10, "a") == "aaaaaaaaaa"
     */
    String ptr = CARP_MALLOC(len + 1);
    if (ptr != NULL) {
        // calling memset(NULL,...) would exercise undefined behaviour...
        memset(ptr, byte, len);
        ptr[len] = '\0';
    }
    return ptr;
}

void String_delete(String s) {
    CARP_FREE(s);
}

void String_string_MINUS_set_BANG_(String *s, int i, char ch) {
    CHK_INDEX(i, strlen(*s));
    (*s)[i] = ch;
}

void String_string_MINUS_set_MINUS_at_BANG_(String *into, int i,
                                            const String *src) {
    char *dest = (*into) + i;
    size_t lsrc = strlen(*src);
    /* given a string and indices
     *
     *  0 1 2 3 4 5 6 7 8 9
     * "a b c d e f g h i j"
     * linto = strlen(...) = 10
     *
     * if we want to insert at '6' a string of length '4'
     *
     *  0 1 2 3
     * "w x y z"
     * lsrc = strlen(...) = 4
     *
     * we need to make sure that the new string will not grow the first
     *
     *  0 1 2 3 4 5 6 7 8 9
     * "a b c d e f g h i j"
     *              ^
     *              |
     *              0 1 2 3
     *             "w x y z"
     *
     * we check this by
     *      (i + lsrc) < (linto + 1)
     *      (6 +    4) < (10    + 1)
     *      10         < 11
     *      true
     *
     * so this write is safe
     */
    CHK_INDEX(i + lsrc, strlen(*into) + 1);
    memcpy(dest, *src, lsrc);
}

String String_copy(const String *s) {
    size_t len = strlen(*s) + 1;
    String ptr = CARP_MALLOC(len);
    return (String)memcpy(ptr, *s, len);
}

bool String__EQ_(const String *a, const String *b) {
    return strcmp(*a, *b) == 0;
}

bool String__GT_(const String *a, const String *b) {
    return strcmp(*a, *b) > 0;
}

bool String__LT_(const String *a, const String *b) {
    return strcmp(*a, *b) < 0;
}

String String_append(const String *a, const String *b) {
    int la = strlen(*a);
    int lb = strlen(*b);
    int total = la + lb + 1;
    String buffer = CARP_MALLOC(total);
    memcpy(buffer, *a, la);
    memcpy(buffer + la, *b, lb);
    buffer[la + lb] = '\0';
    return buffer;
}

int String_length(const String *s) {
    return strlen(*s);
}

char *String_cstr(const String *s) {
    return *s;
}

String String_from_MINUS_cstr(char *s) {
    return String_copy(&s);
}

String String_str(const String *s) {
    return String_copy(s);
}

int count_occurrences(String s, char c) {
    int res = 0;
    while (*s != '\0') {
        if (*s == c) res++;
        s++;
    }
    return res;
}

String String_prn(const String *s) {
    int n = strlen(*s) + 4 + count_occurrences(*s, '"');
    String buffer = CARP_MALLOC(n);
    buffer[0] = '@';
    buffer[1] = '"';
    String c = *s;
    for (int i = 2; i < n - 2; i++) {
        if (*c == '"') buffer[i++] = '\\';
        buffer[i] = *c;
        c++;
    }
    buffer[n - 2] = '"';
    buffer[n - 1] = '\0';
    return buffer;
}

char String_char_MINUS_at(const String *s, int i) {
    return (*s)[i];
}

String String_format(const String *str, const String *s) {
    int size = snprintf(NULL, 0, *str, *s) + 1;
    String buffer = CARP_MALLOC(size);
    sprintf(buffer, *str, *s);
    return buffer;
}

Array String_chars(const String *ps) {
    Char *data;
    Array chars;
    const char *s = *ps;
    const uint8_t *us = (const uint8_t *)s;
    uint32_t state = 0;
    uint32_t cp = 0;
    size_t l = utf8len(s);
    chars.len = l;
    chars.capacity = l;
    data = CARP_MALLOC(chars.capacity * sizeof(*data));
    for (size_t si = 0, di = 0; di < l; si++) {
        uint32_t r = utf8decode(&state, &cp, us[si]);
        switch (r) {
            case UTF8_ACCEPT:
                data[di++] = cp;
                cp = 0;
                break;
            case UTF8_REJECT:
                data[di++] = 0xfffd;  // REPLACEMENT CHARACTER
                cp = 0;
                break;
        }
    }
    chars.data = data;
    return chars;
}

String String_from_MINUS_chars(const Array *a) {
    Char *data = (Char *)a->data;
    size_t cnt = a->len;
    size_t sz = wutf8len(data, cnt) + 1;
    String s = CARP_MALLOC(sz);
    size_t sofar = 0;
    for (size_t i = 0; i < cnt; i++) sofar += utf8encode(s + sofar, data[i]);
    s[sofar++] = 0;
    assert(sofar == sz);
    return s;
}

String String_tail(const String *s) {
    size_t len = strlen(*s);
    String news = CARP_MALLOC(len);
    memcpy(news, (*s) + 1, len - 1);
    news[len - 1] = '\0';
    return news;
}

String String_empty() {
    String s = CARP_MALLOC(1);
    s[0] = '\0';
    return s;
}

Array String_to_MINUS_bytes(const String *s) {
    Array chars;
    const uint8_t *us = (const uint8_t *)*s;
    size_t l = strlen(*s);
    chars.len = l;
    chars.capacity = l;
    chars.data = CARP_MALLOC(chars.capacity);
    memcpy(chars.data, us, l);
    return chars;
}

String String_from_MINUS_bytes(Array *a) {
    String s;
    const char *us = (const char *)a->data;
    s = CARP_MALLOC(a->len + 1);
    memcpy(s, us, a->len);
    s[a->len] = '\0';
    return s;
}

String Bool_str(bool b) {
    const String true_str = "true";
    const String false_str = "false";
    if (b) {
        return String_copy(&true_str);
    } else {
        return String_copy(&false_str);
    }
}

String Bool_format(const String *str, bool b) {
    int size = snprintf(NULL, 0, *str, b) + 1;
    String buffer = CARP_MALLOC(size);
    sprintf(buffer, *str, b);
    return buffer;
}

String Char_str(Char c) {
    char buf[16];
    size_t sz = utf8encode(buf, c);
    size_t nsz = sz + 1;
    String buffer = CARP_MALLOC(nsz);
    memcpy(buffer, buf, nsz);
    buffer[nsz - 1] = 0;
    return buffer;
}

String Char_prn(Char c) {
    char buf[16];
    size_t sz = utf8encode(buf, c);
    size_t nsz = sz + 1 + 1;
    String buffer = CARP_MALLOC(nsz);
    buffer[0] = '\\';
    memcpy(buffer + 1, buf, sz);
    buffer[nsz - 1] = 0;
    return buffer;
}

String Char_format(const String *str, char b) {
    int size = snprintf(NULL, 0, *str, b) + 1;
    String buffer = CARP_MALLOC(size);
    sprintf(buffer, *str, b);
    return buffer;
}

String Double_str(double x) {
    int size = snprintf(NULL, 0, "%g", x) + 1;
    String buffer = CARP_MALLOC(size);
    sprintf(buffer, "%g", x);
    return buffer;
}

String Double_format(const String *s, double x) {
    int size = snprintf(NULL, 0, *s, x) + 1;
    String buffer = CARP_MALLOC(size);
    sprintf(buffer, *s, x);
    return buffer;
}

bool Double_from_MINUS_string_MINUS_internal(const String *s, double *target) {
    char *err;
    *target = strtod(*s, &err);
    return *err == 0;
}

String Float_str(float x) {
    int size = snprintf(NULL, 0, "%gf", x) + 1;
    String buffer = CARP_MALLOC(size);
    sprintf(buffer, "%gf", x);
    return buffer;
}

String Float_format(const String *str, float x) {
    int size = snprintf(NULL, 0, *str, x) + 1;
    String buffer = CARP_MALLOC(size);
    sprintf(buffer, *str, x);
    return buffer;
}

bool Float_from_MINUS_string_MINUS_internal(const String *s, float *target) {
    char *err;
    *target = strtof(*s, &err);
    return *err == 0;
}

String Int_str(int x) {
    int size = snprintf(NULL, 0, "%d", x) + 1;
    String buffer = CARP_MALLOC(size);
    sprintf(buffer, "%d", x);
    return buffer;
}

String Int_format(const String *str, int x) {
    int size = snprintf(NULL, 0, *str, x) + 1;
    String buffer = CARP_MALLOC(size);
    sprintf(buffer, *str, x);
    return buffer;
}

bool Int_from_MINUS_string_MINUS_internal(const String *s, int *target) {
    char *err;
    *target = (int)strtol(*s, &err, 10);
    return *err == 0;
}

String Long_str(Long x) {
    int size = snprintf(NULL, 0, "%" PRIi64, x) + 1;
    String buffer = CARP_MALLOC(size);
    sprintf(buffer, "%" PRIi64, x);
    return buffer;
}

String Long_format(const String *str, Long x) {
    int size = snprintf(NULL, 0, *str, x) + 1;
    String buffer = CARP_MALLOC(size);
    sprintf(buffer, *str, x);
    return buffer;
}

bool Long_from_MINUS_string_MINUS_internal(const String *s, Long *target) {
    char *err;
    *target = strtol(*s, &err, 10);
    return *err == 0;
}

String Byte_str(uint8_t x) {
    int size = snprintf(NULL, 0, "%ub", x) + 1;
    String buffer = CARP_MALLOC(size);
    sprintf(buffer, "%ub", x);
    return buffer;
}

String Byte_format(const String *str, uint8_t x) {
    int size = snprintf(NULL, 0, *str, x) + 1;
    String buffer = CARP_MALLOC(size);
    sprintf(buffer, *str, x);
    return buffer;
}

uint8_t Byte_from_MINUS_string_MINUS_internal(const String *s, byte *target) {
    char *err;
    *target = (uint8_t)strtol(*s, &err, 10);
    return *err == 0;
}

int String_index_MINUS_of_MINUS_from(const String *s, char c, int i) {
    /* Return index of first occurrence of `c` in `s` AFTER index i
     * Returns -1 if not found
     */
    ++i;  // skip first character as we want AFTER i
    size_t len = strlen(*s);
    for (; i < len; ++i) {
        if (c == (*s)[i]) {
            return i;
        }
    }
    return -1;
}

int String_index_MINUS_of(const String *s, char c) {
    /* Return index of first occurrence of `c` in `s`
     * Returns -1 if not found
     */
    return String_index_MINUS_of_MINUS_from(s, c, -1);
}

String Pointer_strp(void *in) {
    int size = snprintf(NULL, 0, "%p", in) + 1;
    String buffer = CARP_MALLOC(size);
    sprintf(buffer, "%p", in);
    return buffer;
}