package me.bill.fakePlayerPlugin.util;

import org.bukkit.attribute.Attribute;

/**
 * Version-safe attribute lookup helper.
 *
 * <p>Paper 1.21.3+ introduced shorthand enum constants without the {@code GENERIC_} prefix
 * (e.g. {@code MAX_HEALTH}). Older servers (1.21.1 and below) only have the legacy names
 * (e.g. {@code GENERIC_MAX_HEALTH}). Referencing the new constant directly in bytecode causes
 * a {@link NoSuchFieldError} at runtime on servers that don't have it yet.
 *
 * <p>This class resolves the correct constant once at class-load time via reflection so the
 * rest of the codebase can call {@link #maxHealth()} without any version branching.
 */
public final class AttributeCompat {

  /**
   * Resolved at class-load; never null unless the server is very broken.
   */
  public static final Attribute MAX_HEALTH = resolve("MAX_HEALTH", "GENERIC_MAX_HEALTH");

  private AttributeCompat() {
  }

  /**
   * Returns the max-health {@link Attribute} constant that exists on the current server,
   * or {@code null} if neither name could be found (should never happen on any supported version).
   */
  public static Attribute maxHealth() {
    return MAX_HEALTH;
  }

  // ── internal ──────────────────────────────────────────────────────────────

  @SuppressWarnings("unchecked")
  private static <T extends Attribute> T resolve(String... names) {
    for (String name : names) {
      try {
        return (T) Attribute.class.getField(name).get(null);
      } catch (NoSuchFieldException ignored) {
        // try next candidate
      } catch (Exception e) {
        FppLogger.warn("AttributeCompat: unexpected error resolving '" + name + "': " + e.getMessage());
      }
    }
    FppLogger.warn("AttributeCompat: could not resolve any of: " + String.join(", ", names));
    return null;
  }
}