import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpRequest.BodyPublishers;
import java.net.http.HttpResponse;
import java.nio.charset.StandardCharsets;
import java.time.Duration;
import java.util.Base64;

/**
 * Minimal Java 11+ cookbook against the vSphere REST gateway using a Basic-auth
 * session (vmware-api-session-id).
 *
 *   javac Cookbook.java && java Cookbook
 */
public final class Cookbook {
  private static final HttpClient CLIENT =
      HttpClient.newBuilder().sslContext(insecureSslContext()).build();

  public static void main(String[] args) throws Exception {
    String base = env("VSPHERE_BASE", "https://localhost");
    String user = env("VSPHERE_USER", "administrator@vsphere.local");
    String password = env("VSPHERE_PASSWORD", "VMware1!");
    String vmName = env("VSPHERE_VM_NAME", "java-lab-01");

    String auth =
        "Basic " + Base64.getEncoder().encodeToString((user + ":" + password).getBytes(StandardCharsets.UTF_8));
    String sessionId = unquote(send(post(base + "/api/session", auth, null)));
    System.out.println("session: " + sessionId);

    String vms = send(get(base + "/api/vcenter/vm", sessionId));
    System.out.println("vms before: " + vms.length() + " bytes");

    String createBody =
        "{\"name\":\""
            + vmName
            + "\",\"guest_OS\":\"OTHER_GUEST_64\","
            + "\"placement\":{\"folder\":\"group-v23\",\"host\":\"host-11\","
            + "\"datastore\":\"datastore-31\",\"resource_pool\":\"resgroup-22\"},"
            + "\"cpu\":{\"count\":1},\"memory\":{\"size_MiB\":512}}";
    String moid = unquote(send(postJson(base + "/api/vcenter/vm", sessionId, createBody)));
    System.out.println("created: " + moid);

    String power = send(post(base + "/api/vcenter/vm/" + moid + "/power?action=start", sessionId, null));
    waitTask(base, sessionId, extractField(power, "task"));

    String detail = send(get(base + "/api/vcenter/vm/" + moid, sessionId));
    System.out.println("power_state: " + extractField(detail, "power_state"));

    power = send(post(base + "/api/vcenter/vm/" + moid + "/power?action=stop", sessionId, null));
    waitTask(base, sessionId, extractField(power, "task"));

    send(delete(base + "/api/vcenter/vm/" + moid, sessionId));
    send(delete(base + "/api/session", sessionId));
    System.out.println("ok");
  }

  private static void waitTask(String base, String sessionId, String task) throws Exception {
    if (task == null || task.isBlank()) {
      return;
    }
    long deadline = System.currentTimeMillis() + 120_000;
    while (System.currentTimeMillis() < deadline) {
      String body = send(get(base + "/api/cis/tasks/" + task, sessionId));
      String status = extractField(body, "status");
      if ("SUCCEEDED".equals(status) || "FAILED".equals(status)) {
        return;
      }
      Thread.sleep(300);
    }
    throw new IllegalStateException("timeout waiting for task " + task);
  }

  private static String env(String key, String def) {
    String value = System.getenv(key);
    return value == null || value.isBlank() ? def : value;
  }

  private static HttpRequest get(String uri, String sessionId) {
    return HttpRequest.newBuilder(URI.create(uri))
        .timeout(Duration.ofSeconds(60))
        .header("vmware-api-session-id", sessionId)
        .GET()
        .build();
  }

  private static HttpRequest post(String uri, String auth, String body) {
    HttpRequest.Builder builder =
        HttpRequest.newBuilder(URI.create(uri)).timeout(Duration.ofSeconds(60));
    if (auth.startsWith("Basic ")) {
      builder.header("Authorization", auth);
    } else {
      builder.header("vmware-api-session-id", auth);
    }
    return builder.POST(body == null ? BodyPublishers.noBody() : BodyPublishers.ofString(body)).build();
  }

  private static HttpRequest postJson(String uri, String sessionId, String body) {
    return HttpRequest.newBuilder(URI.create(uri))
        .timeout(Duration.ofSeconds(60))
        .header("vmware-api-session-id", sessionId)
        .header("Content-Type", "application/json")
        .POST(BodyPublishers.ofString(body))
        .build();
  }

  private static HttpRequest delete(String uri, String sessionId) {
    return HttpRequest.newBuilder(URI.create(uri))
        .timeout(Duration.ofSeconds(60))
        .header("vmware-api-session-id", sessionId)
        .DELETE()
        .build();
  }

  private static String send(HttpRequest request) throws Exception {
    HttpResponse<String> response = CLIENT.send(request, HttpResponse.BodyHandlers.ofString());
    if (response.statusCode() >= 300) {
      throw new RuntimeException(response.statusCode() + ": " + response.body());
    }
    return response.body();
  }

  private static String unquote(String value) {
    String trimmed = value.trim();
    if (trimmed.startsWith("\"") && trimmed.endsWith("\"")) {
      return trimmed.substring(1, trimmed.length() - 1);
    }
    return trimmed;
  }

  /** Tiny string-based field extraction — good enough for a lab smoke, no JSON library required. */
  private static String extractField(String body, String field) {
    String marker = "\"" + field + "\":";
    int start = body.indexOf(marker);
    if (start < 0) {
      return "";
    }
    start += marker.length();
    while (start < body.length() && (body.charAt(start) == ' ' || body.charAt(start) == '"')) {
      start++;
    }
    int end = start;
    while (end < body.length() && body.charAt(end) != '"' && body.charAt(end) != ',' && body.charAt(end) != '}') {
      end++;
    }
    return body.substring(start, end);
  }

  private static javax.net.ssl.SSLContext insecureSslContext() {
    try {
      javax.net.ssl.TrustManager[] trustAll =
          new javax.net.ssl.TrustManager[] {
            new javax.net.ssl.X509TrustManager() {
              public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                return new java.security.cert.X509Certificate[0];
              }

              public void checkClientTrusted(java.security.cert.X509Certificate[] certs, String authType) {}

              public void checkServerTrusted(java.security.cert.X509Certificate[] certs, String authType) {}
            }
          };
      javax.net.ssl.SSLContext context = javax.net.ssl.SSLContext.getInstance("TLS");
      context.init(null, trustAll, new java.security.SecureRandom());
      return context;
    } catch (Exception error) {
      throw new RuntimeException(error);
    }
  }
}