#pragma once
#ifndef CFFI_CDEF_MODE
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#endif
#include "config.h"

#ifdef __cplusplus
extern "C" {
#endif

#ifdef _WIN32
#define THREAD_LOCAL __declspec(thread)
#define ATTRIBUTE(A)
#else
#define THREAD_LOCAL _Thread_local
#define ATTRIBUTE(A) __attribute__(A)
#endif  // _WIN32

enum CNO_ERRNO {
  CNO_OK = 0,
  CNO_ERRNO_ASSERTION = 1,
  CNO_ERRNO_NO_MEMORY = 2,
  CNO_ERRNO_NOT_IMPLEMENTED = 3,
  CNO_ERRNO_PROTOCOL = 4,        // (irrecoverable) protocol error
  CNO_ERRNO_INVALID_STREAM = 6,  // cno_write_* with wrong arguments
  CNO_ERRNO_WOULD_BLOCK = 7,  // would go above the limit on concurrent streams
                              // - wait for a request to complete
  CNO_ERRNO_DISCONNECT = 9,   // connection has already been closed
};

struct cno_error_t {
  int code;
  char text[256];
};

// Return some information about the last error in the current thread.
const struct cno_error_t *cno_error(void);

// Fail with a specified error code and message.
int cno_error_set(int code, const char *fmt, ...)
    ATTRIBUTE((format(printf, 2, 3)));

#define CNO_ERROR(n, ...) cno_error_set(CNO_ERRNO_##n, __VA_ARGS__)
#define CNO_ERROR_UP() (-1)

struct cno_buffer_t {
  // depending on where this thing is used, it may hold either binary octets
  // or human-readable data (http headers). casting the buffer to uint8_t
  // where necessary is easy, converting all string literals to uint8_t is not.
  const char *data;
  size_t size;
};

struct cno_buffer_dyn_t {
  char *data;
  size_t size;
  size_t offset;
  size_t cap;
};

// cffi does not compile inline functions
#ifndef CFFI_CDEF_MODE

static inline int cno_strncasecmp(const char *s1, const char *s2, size_t n) {
#ifdef _WIN32
  return _strnicmp(s1, s2, n);
#else
  return strncasecmp(s1, s2, n);
#endif
}

#define CNO_BUFFER_CONST_STRING(STR) \
  (struct cno_buffer_t) { STR, sizeof(STR) - 1 }

static inline struct cno_buffer_t CNO_BUFFER_STRING(const char *s) {
  struct cno_buffer_t result = {s, strlen(s)};
  return result;
}

static inline struct cno_buffer_t
CNO_BUFFER_VIEW(const struct cno_buffer_dyn_t b) {
  struct cno_buffer_t result = {b.data, b.size};
  return result;
}

static inline int
cno_buffer_eq(const struct cno_buffer_t a, const struct cno_buffer_t b) {
  return a.size == b.size && 0 == cno_strncasecmp(a.data, b.data, b.size);
}

static inline int cno_buffer_startswith(const struct cno_buffer_t a,
                                        const struct cno_buffer_t b) {
  return a.size >= b.size && 0 == memcmp(a.data, b.data, b.size);
}

static inline int cno_buffer_endswith(const struct cno_buffer_t a,
                                      const struct cno_buffer_t b) {
  return a.size >= b.size &&
         0 == memcmp(a.data + a.size - b.size, b.data, b.size);
}

static inline struct cno_buffer_t cno_buffer_shift(const struct cno_buffer_t x,
                                                   size_t offset) {
  struct cno_buffer_t result = {x.data + offset, x.size - offset};
  return result;
}

static inline struct cno_buffer_t cno_buffer_cut(struct cno_buffer_t *x,
                                                 size_t offset) {
  struct cno_buffer_t ret = {x->data, offset};
  *x = cno_buffer_shift(*x, offset);
  return ret;
}

static inline void cno_buffer_dyn_clear(struct cno_buffer_dyn_t *x) {
  free(x->data - x->offset);
  struct cno_buffer_dyn_t result = {NULL, 0, 0, 0};
  *x = result;
}

static inline void cno_buffer_dyn_shift(struct cno_buffer_dyn_t *x,
                                        size_t off) {
  x->data += off;
  x->size -= off;
  x->cap -= off;
  x->offset += off;
}

static inline int cno_buffer_dyn_reserve(struct cno_buffer_dyn_t *x, size_t n) {
  if (n <= x->cap) return CNO_OK;

  if (n <= x->cap + x->offset) {
    memmove(x->data - x->offset, x->data, x->size);
    x->data -= x->offset;
    x->cap += x->offset;
    x->offset = 0;
    return CNO_OK;
  }

  size_t cap = x->cap + x->offset;
  if (n < cap + CNO_BUFFER_ALLOC_MIN) n = cap + CNO_BUFFER_ALLOC_MIN;
  if (n < cap * CNO_BUFFER_ALLOC_MIN_EXP) n = cap * CNO_BUFFER_ALLOC_MIN_EXP;

  char *m = (char *)malloc(n);
  if (m == NULL) return CNO_ERROR(NO_MEMORY, "%zu bytes", n);
  if (x->data != NULL) memcpy(m, x->data, x->size);
  free(x->data - x->offset);

  x->data = m;
  x->cap = n;
  x->offset = 0;
  return CNO_OK;
}

static inline int cno_buffer_dyn_concat(struct cno_buffer_dyn_t *a,
                                        const struct cno_buffer_t b) {
  if (b.size == 0) return CNO_OK;

  if (cno_buffer_dyn_reserve(a, a->size + b.size)) return CNO_ERROR_UP();

  memcpy(a->data + a->size, b.data, b.size);
  a->size += b.size;
  return CNO_OK;
}

#endif

#ifdef __cplusplus
}
#endif