// https://llvm.org/docs/LibFuzzer.html

#define MG_ENABLE_SOCKET 1
#define MG_ENABLE_LOG 0
#define MG_ENABLE_LINES 1
#define MG_ENABLE_TCPIP 0
#define MG_IO_SIZE (1 * 1024 * 1024)  // Big IO size for fast resizes
#define MG_TLS MG_TLS_BUILTIN

#include "mongoose.c"

#ifdef __cplusplus
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *, size_t);
#else
int LLVMFuzzerTestOneInput(const uint8_t *, size_t);
#endif

// Preprocessor magic, just add/remove functions here and leave the rest alone
#define TABLE(_) \
_(mg_tls_server_recv_hello) \
_(mg_tls_server_recv_finish) \
_(mg_tls_client_recv_hello) \
_(mg_tls_client_recv_finish) \
_(mg_tls_client_recv_ext) \
_(mg_tls_recv_cert_verify) \
// ... 

struct f {
  int (*f)(struct mg_connection *);
  const char *name;
};

struct f f_[] = {
#define ENTRY(func) { func, #func },
TABLE(ENTRY)
#undef ENTRY
};
// end of preprocessor magic



int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
  struct mg_connection c_[sizeof(f_)/sizeof(struct f)], *c = &c_[0];
  struct tls_data tls_[sizeof(f_)/sizeof(struct f)];
  int i;
  if (size == 0) return 0;
  mg_log_set(MG_LL_INFO);
  memset(c, 0, sizeof(*c));
  c->send.align = c->recv.align = c->rtls.align = MG_IO_SIZE;  
  c->is_tls = c->is_tls_hs = 1;
  for (i = 0; i < (int)(sizeof(f_)/sizeof(struct f)); i++) {
    struct mg_iobuf *io;
    c = &c_[i];
    io = &c->rtls;
    if (i > 0) memcpy(c, &c_[0], sizeof(*c)); // copy from 1st one
    if (i > 1) c->is_client = 1;  // from 2 on, client functions
    memset(&tls_[i], 0, sizeof(struct tls_data));
    if (io->size - io->len < size && !mg_iobuf_resize(io, io->len + size)) {
      mg_error(c, "oom");
      return 0; // drop it
    }
    memcpy(&io->buf[io->len], data, size);
    io->len += size;
    c->tls = &tls_[i];
#ifdef PRINT_FUNCNAME
    printf("CALLING %s\n", f_[i].name);
#endif
    f_[i].f(c);
    mg_iobuf_free(io);
  }

  // mg_tls_recv_cert() has an extra bool parameter 
  c = &c_[0]; // reuse first one
  c->tls = &tls_[0];
  for (i = 0; i < 2; i++) {
    struct mg_iobuf *io;
    io = &c->rtls;
    c->is_client = (i > 0);
    memset(c->tls, 0, sizeof(struct tls_data));
    if (io->size - io->len < size && !mg_iobuf_resize(io, io->len + size)) {
      mg_error(c, "oom");
      return 0; // drop it
    }
    memcpy(&io->buf[io->len], data, size);
    io->len += size;
#ifdef PRINT_FUNCNAME
    printf("CALLING mg_tls_recv_cert\n");
#endif
    mg_tls_recv_cert(c, !c->is_client); // call server for client and client for server
    mg_iobuf_free(io);
  }

  return 0;
}

#if defined(MAIN)
int main(int argc, char *argv[]) {
  int res = EXIT_FAILURE;
  if (argc > 1) {
    struct mg_str data = mg_file_read(&mg_fs_posix, argv[1]);
    if (data.buf != NULL) {
      LLVMFuzzerTestOneInput((uint8_t *) data.buf, data.len);
      res = EXIT_SUCCESS;
    }
    free(data.buf);
  }
  return res;
}
#endif