#include "str.h"
#include "crash.h"
#include <stdlib.h>
#include <string.h>

#define CRASH_IF_OOB(str, len) {\
    if (len > str->length)\
        crash(\
            "String does not have expected length: %ld > %ld\n",\
            len,\
            str->length);\
}

static inline char* alloc_data_ptr(size_t length) {
    char* data_ptr = malloc(length);
    if (data_ptr == NULL)
        crash("Out of memory allocating new string of length %ld\n", length);
    return data_ptr;
}

static inline char* alloc_c_str(size_t length) {
    char* c_str = malloc(length + 1);
    if (c_str == NULL)
        crash("Out of memory allocating C string buffer of size %ld", length + 1);

    c_str[length] = 0;
    return c_str;
}

char* str_at(const str_t* str, size_t idx) {
    CRASH_IF_OOB(str, idx + 1);
    return str->__data + idx;
}

str_t str_slice(const str_t* str, size_t start, size_t length) {
    CRASH_IF_OOB(str, start + length);
    return (str_t) {.length = length, .__data = str->__data + start};
}

int str_cmp(const str_t* s1, const str_t* s2) {
    if (s1->length == s2->length)
        return memcmp(s1->__data, s2->__data, s1->length);
    else if (s1->length > s2->length) {
        int cmp = memcmp(s1->__data, s2->__data, s2->length);
        if (cmp != 0) return cmp;
        return 1;
    } else {
        int cmp = memcmp(s1->__data, s2->__data, s1->length);
        if (cmp != 0) return cmp;
        return -1;
    }
}

ssize_t str_indexof(const str_t* str, char c) {
    for (ssize_t i = 0; i < str->length; i++) {
        if (str->__data[i] == c) return i;
    }
    return -1;
}

ssize_t str_rindexof(const str_t* str, char c) {
    for (ssize_t i = (ssize_t)str->length - 1; i >= 0; i--) {
        if (str->__data[i] == c) return i;
    }
    return -1;
}

str_t str_heap_dup(const str_t* str) {
    char* data_ptr = alloc_data_ptr(str->length);
    memcpy(data_ptr, str->__data, str->length);
    return (str_t) {.length = str->length, .__data = data_ptr};
}

str_t str_heap_cat(const str_t* s1, const str_t* s2) {
    size_t new_len = s1->length + s2->length;
    char* data_ptr = alloc_data_ptr(new_len);
    memcpy(data_ptr, s1->__data, s1->length);
    memcpy(data_ptr + s1->length, s2->__data, s2->length);
    return (str_t) {.length = new_len, .__data = data_ptr};
}

void str_to_c_str(char* dst, size_t dst_size, const str_t* src) {
    if (src->length >= dst_size)
        crash(
            "String is too long to hold in C string buffer: %ld >= %ld\n",
            src->length,
            dst_size);

    memmove(dst, src->__data, src->length);
    dst[src->length] = 0;
}

char* str_to_heap_c_str(const str_t* src) {
    char* dst = alloc_c_str(src->length);
    memcpy(dst, src->__data, src->length);
    return dst;
}

str_t str_heap_alloc(size_t length) {
    char* data_ptr = alloc_data_ptr(length);
    return (str_t) {.length = length, .__data = data_ptr};
}

str_t str_heap_init(const char* c_str, size_t length) {
    return str_heap_init_slice(c_str, 0, length);
}

str_t str_heap_init_slice(const char* c_str, size_t start, size_t length) {
    char* data_ptr = alloc_data_ptr(length);
    memcpy(data_ptr, c_str + start, length);
    return (str_t) {.length = length, .__data = data_ptr};
}

void str_heap_destroy(str_t* str) {
    free(str->__data);
}