#include <string.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
#include "ucore/dstr.h"
#include "ucore/utils.h"

void uc_dstr_init(struct DStr *str)
{
    str->len = 0;
    str->allocated = 0;
    str->str = NULL;
}

void uc_dstr_destroy(struct DStr *str)
{
#ifdef DEBUG
    if (str->str) {
        memset(str->str, 0xcc, str->allocated);
    }
    str->len = -1;
    str->allocated = -1;
#endif
    free(str->str);
}

int uc_dstr_copy(struct DStr *dest, const struct DStr *src)
{
    char *s;

    uc_dstr_init(dest);
    if (src->allocated == 0) {
        return 0;
    }

    s = uc_dstr_put(dest, src->len);
    if (s == NULL) {
        return -1;
    }

    //+1 to copy a potential nul terminator, uc_dstr_put 
    //guarantees we have room for it.
    memcpy(s, src->str, UC_MIN(src->len + 1, src->allocated));

    return 0;
}

size_t uc_dstr_available(const struct DStr *str)
{
    return str->allocated - str->len;
}

int uc_dstr_ensure(struct DStr *str, size_t total)
{
    if (str->allocated < total) {
        //allocate a minimum no. of bytes, and one
        //additional for the common case of nul terminating
        //the string
        size_t new_len = UC_MAX(7U, total) + 1;
        char *new_str = realloc(str->str, new_len);

        if (new_str == NULL) {
            return -1;
        }
        str->str = new_str;
        str->allocated = new_len;
    }

    return 0;
}

void uc_dstr_reset(struct DStr *str)
{
    str->len = 0;
#ifdef DEBUG
    if (str->str) {
        memset(str->str, 0xcc, str->allocated);
    }
#endif
}

void uc_dstr_terminate(struct DStr *str)
{
    uc_dstr_ensure(str, str->len + 1);
    str->str[str->len] = 0;
}

char *uc_dstr_str(struct DStr *str)
{
    uc_dstr_terminate(str);

    return str->str;
}

char *uc_dstr_put(struct DStr *str, size_t len)
{
    char *start;

    if (uc_dstr_ensure(str, str->len + len) != 0) {
        return NULL;
    }

    start = str->str + str->len;
    str->len += len;

    return start;
}

size_t uc_dstr_put_str_filter(struct DStr *str, const char *s, int (*is_x)(int c))
{
    size_t len = strlen(s);
    size_t i;
    size_t idx = 0;

    if (uc_dstr_ensure(str, str->len + len) != 0) {
        return 0;
    }

    for (i = 0; i < len; i++) {
        if (is_x(s[i])) {
            str->str[str->len + idx]= s[i];
            idx++;
        }
    }

    str->len += idx;

    return idx;
}

int uc_dstr_put_str_sz(struct DStr *str, const char *s, size_t len)
{
    char *start = uc_dstr_put(str, len);

    if (start == NULL) {
        return -1;
    }
    memcpy(start, s, len);

    return 0;
}

int uc_dstr_put_str(struct DStr *str, const char *s)
{
    size_t len = strlen(s);

    return uc_dstr_put_str_sz(str, s ,len);
}

int uc_dstr_put_char(struct DStr *str, char c)
{
    char *start = uc_dstr_put(str, 1);

    if (start == NULL) {
        return -1;
    }
    *start = c;

    return 0;
}

void uc_dstr_own(struct DStr *str, char *s)
{
    size_t len = strlen(s);

    if (str->str) {
        free(str);
    }

    str->len = len;
    str->allocated = len + 1;
    str->str = s;
}

char *uc_dstr_steal(struct DStr *str)
{
    char *s = str->str;

    uc_dstr_init(str);

    return s;
}

void uc_str_swap(struct DStr *a, struct DStr *b)
{
    struct DStr tmp;

    tmp = *a;
    *a = *b;
    *b = tmp;
}

size_t uc_dstr_replace(struct DStr *str, char f, char r)
{
    size_t i;
    size_t count = 0;

    if (str->len == 0) {
        return 0;
    }

    for (i = 0; i < str->len; i++) {
        if (str->str[i] == f) {
            str->str[i] = r;
            count++;
        }
    }

    return count;
}

void uc_dstr_trim(struct DStr *str)
{
    size_t spaces;

    uc_dstr_terminate(str);

    //spaces at the start
    spaces = strspn(str->str, " \t\n\v\f\r");
    if (spaces > 0) {
        memmove(str->str, str->str + spaces, str->len - spaces);
        str->len -= spaces;
    }

    //spaces at the end
    if (str->len > 0) {
        size_t idx = str->len - 1;
        do {
            if (strchr(" \t\n\v\f\r", str->str[idx]) == NULL) {
                break;
            } else {
                str->len--;
                idx--;
            }
        } while (idx != 0);
    }
}

int uc_dstr_sprintf(struct DStr *str, const char *fmt, ...)
{
    va_list ap;
    int rc;

    va_start(ap, fmt);
    rc = uc_dstr_vsprintf(str, fmt, ap);
    va_end(ap);

    return rc;
}

int uc_dstr_vsprintf(struct DStr *str, const char *fmt, va_list ap_)
{
    va_list ap;
    int rc;
    int available;
    int needed;

    rc = uc_dstr_ensure(str, str->len + 1);
    if (rc != 0) {
        return -1;
    }

    available = uc_dstr_available(str);

    va_copy(ap, ap_);
    needed = vsnprintf(str->str + str->len, available, fmt, ap);
    va_end(ap);

    if (needed <= 0) {
        return needed;
    }

    if (needed >= available) {
        rc = uc_dstr_ensure(str, str->len + needed);
        if (rc != 0) {
            return -1;
        }

        available = uc_dstr_available(str);

        va_copy(ap, ap_);
        needed = vsnprintf(str->str + str->len, available, fmt, ap);
        va_end(ap);
    }

    str->len += needed;

    return needed;
}