#include "astr.h"

#include <errno.h>
#include <stdio.h>


char *
astr_alloc_formatted(char const *format, ...)
{
    va_list arguments;
    va_start(arguments, format);
    char *s = astr_alloc_formatted_from_va_list(format, arguments);
    va_end(arguments);
    return s;
}


char *
astr_alloc_formatted_from_va_list(char const *format, va_list arguments)
{
    if (!format) {
        errno = EINVAL;
        return NULL;
    }

    char *s;
    va_list arguments_copy;
    va_copy(arguments_copy, arguments);
    int chars_printed = vasprintf(&s, format, arguments_copy);
    if (chars_printed < 0) return NULL;
    return s;
}


size_t
astr_formatted_length(char const *format, ...)
{
    va_list arguments;
    va_start(arguments, format);
    size_t length = astr_formatted_length_from_va_list(format, arguments);
    va_end(arguments);
    return length;
}


size_t
astr_formatted_length_from_va_list(char const *format, va_list arguments)
{
    if (!format) {
        errno = EINVAL;
        return 0;
    }

    va_list arguments_copy;
    va_copy(arguments_copy, arguments);
    int length = vsnprintf(NULL, 0, format, arguments_copy);
    if (length < 0) return 0;
    return length;
}


int
astr_realloc_append_formatted(char **s, char const *format, ...)
{
    va_list arguments;
    va_start(arguments, format);
    int result = astr_realloc_append_formatted_from_va_list(s, format, arguments);
    va_end(arguments);
    return result;
}


int
astr_realloc_append_formatted_from_va_list(char **s, 
                                           char const *format, 
                                           va_list arguments)
{
    if (!s || !format) {
        errno = EINVAL;
        return -1;
    }

    size_t length_to_append = astr_formatted_length_from_va_list(format, arguments);
    if (!length_to_append) return 0;

    size_t original_length = *s ? strlen(*s) : 0;
    size_t new_size = original_length + length_to_append + sizeof('\0');
    char *resized_s = realloc(*s, new_size);
    if (!resized_s) return -1;

    *s = resized_s;
    char *end_of_s = *s + original_length;
    va_list arguments_copy;
    va_copy(arguments_copy, arguments);
    vsprintf(end_of_s, format, arguments_copy);
    return 0;
}


extern char *
astr_alloc_empty(void);

extern int 
astr_cmp(char const *s1, char const *s2);

extern bool
astr_empty(char const *s);

extern bool
astr_eq(char const *s1, char const *s2);