/* A C program against libwai, as a C developer writes one (wai/quickstart/test/c-library.sh):
 *
 *   cc -std=c11 hello.c $(pkg-config --cflags --libs wai) -o hello && ./hello
 *
 * It packs an envelope, reads its version, unpacks it and compares the payload byte for byte,
 * has a buffer that is no envelope refused with a reason, and reads the native sink's interface
 * version. It prints one line and exits 0, or says what failed and exits 1. */
#include <stdint.h>
#include <stdio.h>
#include <string.h>

#include <wai.h>

static int fail(const char *what) {
  const char *why = wai_last_error();
  fprintf(stderr, "hello: %s: %s\n", what, why ? why : "(no reason)");
  return 1;
}

int main(void) {
  static const char manifest[] =
      "{\"wai\":\"1.0\",\"media\":\"text\",\"intent\":\"replicate\","
      "\"model_requirement\":{\"capability\":\"wai.text.zstd\"},"
      "\"conditioning\":{\"kind\":\"zstd\"},\"target\":null}";
  static const uint8_t payload[] = "a payload carried byte for byte";
  static const uint8_t junk[] = "these bytes are no envelope";
  struct wai_buffer_t env = {0}, man = {0}, pay = {0}, man2 = {0}, pay2 = {0};

  if (wai_envelope_pack(manifest, payload, sizeof payload, &env) != WAI_OK) return fail("pack");
  if (wai_envelope_detect_version(env.data, env.len) != 1) return fail("the packed envelope's version");
  if (wai_envelope_unpack(env.data, env.len, &man, &pay) != WAI_OK) return fail("unpack");
  if (pay.len != sizeof payload || memcmp(pay.data, payload, sizeof payload) != 0) {
    fprintf(stderr, "hello: the unpacked payload is not the packed one\n");
    return 1;
  }
  if (man.len == 0 || memchr(man.data, '{', man.len) == NULL) {
    fprintf(stderr, "hello: the unpacked manifest is not a JSON object\n");
    return 1;
  }
  if (wai_envelope_unpack(junk, sizeof junk - 1, &man2, &pay2) == WAI_OK) {
    fprintf(stderr, "hello: bytes that are no envelope were unpacked\n");
    return 1;
  }
  /* The reason is valid until the next call, so it is copied. */
  const char *last = wai_last_error();
  if (last == NULL || last[0] == '\0') {
    fprintf(stderr, "hello: a refusal with no reason\n");
    return 1;
  }
  char why[256];
  snprintf(why, sizeof why, "%s", last);
  uint32_t abi = wai_sink_abi_version();
  if (abi != WAI_SINK_ABI_VERSION) {
    fprintf(stderr, "hello: the native sink's interface is version %u, the header's %u\n", (unsigned)abi,
            (unsigned)WAI_SINK_ABI_VERSION);
    return 1;
  }
  printf("libwai: an envelope of %zu bytes packed and unpacked, its payload byte for byte; "
         "bytes that are no envelope refused (%s); the native sink's interface version %u\n",
         (size_t)env.len, why, (unsigned)abi);
  wai_buffer_free(env);
  wai_buffer_free(man);
  wai_buffer_free(pay);
  wai_buffer_free(man2);
  wai_buffer_free(pay2);
  return 0;
}