package uk.ac.ic.wlgitbridge.server;

import com.google.gson.Gson;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import uk.ac.ic.wlgitbridge.bridge.Bridge;
import uk.ac.ic.wlgitbridge.snapshot.base.JSONSource;
import uk.ac.ic.wlgitbridge.snapshot.push.exception.SnapshotPostException;
import uk.ac.ic.wlgitbridge.snapshot.push.exception.SnapshotPostExceptionBuilder;
import uk.ac.ic.wlgitbridge.snapshot.push.exception.UnexpectedPostbackException;
import uk.ac.ic.wlgitbridge.util.Util;

/*
 * Created by Winston on 17/11/14.
 */
public class PostbackContents implements JSONSource {

  private static final String CODE_SUCCESS = "upToDate";

  private final Bridge bridge;
  private final String projectName;
  private final String postbackKey;

  private final SnapshotPostExceptionBuilder snapshotPostExceptionBuilder;

  private int versionID;
  private SnapshotPostException exception;

  public PostbackContents(Bridge bridge, String projectName, String postbackKey, String contents) {
    this.bridge = bridge;
    this.projectName = projectName;
    this.postbackKey = postbackKey;
    snapshotPostExceptionBuilder = new SnapshotPostExceptionBuilder();
    fromJSON(new Gson().fromJson(contents, JsonElement.class));
  }

  @Override
  public void fromJSON(JsonElement json) {
    JsonObject responseObject = json.getAsJsonObject();
    String code = Util.getCodeFromResponse(responseObject);
    setResult(responseObject, code);
  }

  public void processPostback() throws UnexpectedPostbackException {
    if (exception == null) {
      bridge.postbackReceivedSuccessfully(projectName, postbackKey, versionID);
    } else {
      bridge.postbackReceivedWithException(projectName, postbackKey, exception);
    }
  }

  private void setResult(JsonObject responseObject, String code) {
    if (code.equals(CODE_SUCCESS)) {
      setVersionID(responseObject);
    } else {
      setException(responseObject, code);
    }
  }

  private void setVersionID(JsonObject responseObject) {
    versionID = responseObject.get("latestVerId").getAsInt();
  }

  private void setException(JsonObject responseObject, String code) {
    try {
      exception = snapshotPostExceptionBuilder.build(code, responseObject);
    } catch (UnexpectedPostbackException e) {
      throw new RuntimeException(e);
    }
  }
}