package com.atlassian.asap.core.keys.privatekey;
   
   import com.atlassian.asap.api.exception.CannotRetrieveKeyException;
   import com.atlassian.asap.core.keys.DataUriKeyReader;
   import com.atlassian.asap.core.keys.DataUriUtil;
   import com.atlassian.asap.core.keys.KeyProvider;
   import com.atlassian.asap.core.validator.ValidatedKeyId;
   
   import java.io.StringReader;
  import java.net.URI;
  import java.security.PrivateKey;
  
  import static com.google.common.base.Preconditions.checkArgument;
  
  /**
   * Key provider for keys embedded in data uri.
   *
   * @see DataUriKeyReader
   */
  public class DataUriKeyProvider implements KeyProvider<PrivateKey> {
      static final String URI_SCHEME = "data";
  
      private final String dataUriKeyId;
      private final PrivateKey privateKey;
  
      public DataUriKeyProvider(URI dataUri, DataUriKeyReader dataUriKeyReader) {
          checkArgument(dataUri.isAbsolute(), "URI must be absolute"); // implies that scheme != null
          checkArgument(dataUri.isOpaque(), "URI must not have path components");
          checkArgument(URI_SCHEME.equals(dataUri.getScheme()), "URI must have data scheme");
  
          this.dataUriKeyId = DataUriUtil.getKeyId(dataUri.toString());
          this.privateKey = getKeyFromDataUri(dataUri, dataUriKeyReader);
      }
  
      @Override
      public PrivateKey getKey(ValidatedKeyId keyId) throws CannotRetrieveKeyException {
          if (dataUriKeyId.equals(keyId.getKeyId())) {
              return privateKey;
          } else {
              throw new CannotRetrieveKeyException("Unrecognized key id: " + keyId.getKeyId());
          }
      }
  
      private static PrivateKey getKeyFromDataUri(URI dataUri, DataUriKeyReader keyReader) {
          try (StringReader reader = new StringReader(dataUri.toString())) {
              return keyReader.readPrivateKey(reader);
          } catch (CannotRetrieveKeyException ex) {
              throw new IllegalArgumentException("Unable to parse key from data uri", ex);
          }
      }
  
      @Override
      public String toString() {
          return this.getClass().getSimpleName();
      }
  }