#ifndef KIT_STRING_REF_H
#define KIT_STRING_REF_H

#include "array_ref.h"

#include <assert.h>
#include <string.h>

#ifdef __cplusplus
extern "C" {
#endif

typedef KIT_AR(char) kit_str_t;

#if defined(__GNUC__) || defined(__clang__)
#  pragma GCC diagnostic push
#  pragma GCC diagnostic ignored "-Wunused-function"
#  pragma GCC diagnostic ignored "-Wunknown-pragmas"
#  pragma GCC            push_options
#  pragma GCC            optimize("O3")
#endif

static kit_str_t kit_str(i64 size, char const *static_string) {
  kit_str_t s = { .size = size, .values = (char *) static_string };
  return s;
}

enum {
  KIT_STR_NOT_FOUND = -1,
};

static i64 kit_str_find(kit_str_t a, kit_str_t b) {
  assert(a.size >= 0 && (a.size == 0 || a.values != NULL) &&
         b.size >= 0 && (b.size == 0 || b.values != NULL));
  if (a.size < 0 || (a.size != 0 && a.values == NULL) || b.size < 0 ||
      (b.size != 0 && b.values == NULL))
    return -1;
  for (i64 index = 0; index + b.size <= a.size; index++)
    if (KIT_AR_EQUAL(kit_str(b.size, a.values + index), b))
      return index;
  return -1;
}

static i64 kit_str_find_back(kit_str_t a, kit_str_t b) {
  assert(a.size >= 0 && (a.size == 0 || a.values != NULL) &&
         b.size >= 0 && (b.size == 0 || b.values != NULL));
  if (a.size < 0 || (a.size != 0 && a.values == NULL) || b.size < 0 ||
      (b.size != 0 && b.values == NULL))
    return -1;
  for (i64 index = a.size - b.size; index >= 0; index--)
    if (KIT_AR_EQUAL(kit_str(b.size, a.values + index), b))
      return index;
  return -1;
}

static i64 kit_str_find_n(kit_str_t a, kit_str_t b, i64 n) {
  assert(a.size >= 0 && (a.size == 0 || a.values != NULL) &&
         b.size >= 0 && (b.size == 0 || b.values != NULL));
  if (a.size < 0 || (a.size != 0 && a.values == NULL) || b.size < 0 ||
      (b.size != 0 && b.values == NULL))
    return -1;
  i64 count = 0;
  for (i64 index = 0; index + b.size <= a.size; index++)
    if (KIT_AR_EQUAL(kit_str(b.size, a.values + index), b)) {
      if (count == n)
        return index;
      else
        count++;
    }
  return -1;
}

static i64 kit_str_find_back_n(kit_str_t a, kit_str_t b, i64 n) {
  assert(a.size >= 0 && (a.size == 0 || a.values != NULL) &&
         b.size >= 0 && (b.size == 0 || b.values != NULL));
  if (a.size < 0 || (a.size != 0 && a.values == NULL) || b.size < 0 ||
      (b.size != 0 && b.values == NULL))
    return -1;
  i64 count = 0;
  for (i64 index = a.size - b.size; index >= 0; index--)
    if (KIT_AR_EQUAL(kit_str(b.size, a.values + index), b)) {
      if (count == n)
        return index;
      else
        count++;
    }
  return -1;
}

//  Make a barbarian string for C standard library functions.
//  Not thread safe.
//  Use with caution.
//
static char *kit_make_bs(kit_str_t s) {
  static char buf[8][4096];
  static i32  index = 0;
  i64         n     = s.size;
  if (n > 4095)
    n = 4095;
  if (n > 0)
    memcpy(buf[index], s.values, n);
  buf[index][n] = '\0';
  char *result  = buf[index];
  index         = (index + 1) % 8;
  return result;
}

#if defined(__GNUC__) || defined(__clang__)
#  pragma GCC            pop_options
#  pragma GCC diagnostic pop
#endif

#define KIT_SZ(static_str_) \
  kit_str(sizeof(static_str_) - 1, (static_str_))

#define KIT_WRAP_BS(string_) kit_str(strlen(string_), (string_))

#define KIT_WRAP_STR(...) \
  kit_str((__VA_ARGS__).size, (__VA_ARGS__).values)

#ifndef KIT_DISABLE_SHORT_NAMES
#  define BS(...) kit_make_bs(KIT_WRAP_STR(__VA_ARGS__))
#  define str_t kit_str_t
#  define str kit_str
#  define str_find kit_str_find
#  define str_find_back kit_str_find_back
#  define str_find_n kit_str_find_n
#  define str_find_back_n kit_str_find_back_n
#  define STR_NOT_FOUND KIT_STR_NOT_FOUND
#  define SZ KIT_SZ
#  define WRAP_BS KIT_WRAP_BS
#  define WRAP_STR KIT_WRAP_STR
#endif

#ifdef __cplusplus
}
#endif

#endif