package com.box.sdk;

import com.eclipsesource.json.Json;
import com.eclipsesource.json.JsonArray;
import com.eclipsesource.json.JsonObject;
import com.eclipsesource.json.JsonValue;
import java.net.URL;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

/** Represents a task on Box. Tasks can have a due date and can be assigned to a specific user. */
@BoxResourceType("task")
public class BoxTask extends BoxResource {

  /** Task URL Template. */
  public static final URLTemplate TASK_URL_TEMPLATE = new URLTemplate("tasks/%s");
  /** Get Assignments URL Template. */
  public static final URLTemplate GET_ASSIGNMENTS_URL_TEMPLATE =
      new URLTemplate("tasks/%s/assignments");
  /** Add Task Assignment URL Template. */
  public static final URLTemplate ADD_TASK_ASSIGNMENT_URL_TEMPLATE =
      new URLTemplate("task_assignments");

  /**
   * Constructs a BoxTask for a task with a given ID.
   *
   * @param api the API connection to be used by the task.
   * @param id the ID of the task.
   */
  public BoxTask(BoxAPIConnection api, String id) {
    super(api, id);
  }

  /** Deletes this task. */
  public void delete() {
    URL url = TASK_URL_TEMPLATE.build(this.getAPI().getBaseURL(), this.getID());
    BoxAPIRequest request = new BoxAPIRequest(this.getAPI(), url, "DELETE");
    request.send().close();
  }

  /**
   * Adds a new assignment to this task.
   *
   * @param assignTo the user to assign the assignment to.
   * @return information about the newly added task assignment.
   */
  public BoxTaskAssignment.Info addAssignment(BoxUser assignTo) {
    JsonObject taskJSON = new JsonObject();
    taskJSON.add("type", "task");
    taskJSON.add("id", this.getID());

    JsonObject assignToJSON = new JsonObject();
    assignToJSON.add("id", assignTo.getID());

    JsonObject requestJSON = new JsonObject();
    requestJSON.add("task", taskJSON);
    requestJSON.add("assign_to", assignToJSON);

    URL url = ADD_TASK_ASSIGNMENT_URL_TEMPLATE.build(this.getAPI().getBaseURL());
    BoxJSONRequest request = new BoxJSONRequest(this.getAPI(), url, "POST");
    request.setBody(requestJSON.toString());
    try (BoxJSONResponse response = request.send()) {
      JsonObject responseJSON = Json.parse(response.getJSON()).asObject();

      BoxTaskAssignment addedAssignment =
          new BoxTaskAssignment(this.getAPI(), responseJSON.get("id").asString());
      return addedAssignment.new Info(responseJSON);
    }
  }

  /**
   * Adds a new assignment to this task using user's login as identifier.
   *
   * @param assignToLogin the login of user to assign the task to.
   * @return information about the newly added task assignment.
   */
  public BoxTaskAssignment.Info addAssignmentByLogin(String assignToLogin) {
    JsonObject taskJSON = new JsonObject();
    taskJSON.add("type", "task");
    taskJSON.add("id", this.getID());

    JsonObject assignToJSON = new JsonObject();
    assignToJSON.add("login", assignToLogin);

    JsonObject requestJSON = new JsonObject();
    requestJSON.add("task", taskJSON);
    requestJSON.add("assign_to", assignToJSON);

    URL url = ADD_TASK_ASSIGNMENT_URL_TEMPLATE.build(this.getAPI().getBaseURL());
    BoxJSONRequest request = new BoxJSONRequest(this.getAPI(), url, "POST");
    request.setBody(requestJSON.toString());
    try (BoxJSONResponse response = request.send()) {
      JsonObject responseJSON = Json.parse(response.getJSON()).asObject();

      BoxTaskAssignment addedAssignment =
          new BoxTaskAssignment(this.getAPI(), responseJSON.get("id").asString());
      return addedAssignment.new Info(responseJSON);
    }
  }

  /**
   * Gets any assignments for this task.
   *
   * @return a list of assignments for this task.
   */
  public List<BoxTaskAssignment.Info> getAssignments() {
    URL url = GET_ASSIGNMENTS_URL_TEMPLATE.build(this.getAPI().getBaseURL(), this.getID());
    BoxJSONRequest request = new BoxJSONRequest(this.getAPI(), url, "GET");
    try (BoxJSONResponse response = request.send()) {
      JsonObject responseJSON = Json.parse(response.getJSON()).asObject();

      int totalCount = responseJSON.get("total_count").asInt();
      List<BoxTaskAssignment.Info> assignments = new ArrayList<>(totalCount);
      JsonArray entries = responseJSON.get("entries").asArray();
      for (JsonValue value : entries) {
        JsonObject assignmentJSON = value.asObject();
        BoxTaskAssignment assignment =
            new BoxTaskAssignment(this.getAPI(), assignmentJSON.get("id").asString());
        BoxTaskAssignment.Info info = assignment.new Info(assignmentJSON);
        assignments.add(info);
      }

      return assignments;
    }
  }

  /**
   * Gets an iterable of all the assignments of this task.
   *
   * @param fields the fields to retrieve.
   * @return an iterable containing info about all the assignments.
   */
  public Iterable<BoxTaskAssignment.Info> getAllAssignments(String... fields) {
    final QueryStringBuilder builder = new QueryStringBuilder();
    if (fields.length > 0) {
      builder.appendParam("fields", fields);
    }
    return () -> {
      URL url =
          GET_ASSIGNMENTS_URL_TEMPLATE.buildWithQuery(
              BoxTask.this.getAPI().getBaseURL(), builder.toString(), BoxTask.this.getID());
      return new BoxTaskAssignmentIterator(BoxTask.this.getAPI(), url);
    };
  }

  /**
   * Gets information about this task.
   *
   * @param fields the fields to retrieve.
   * @return info about this task.
   */
  public Info getInfo(String... fields) {
    URL url = TASK_URL_TEMPLATE.build(this.getAPI().getBaseURL(), this.getID());
    if (fields.length > 0) {
      QueryStringBuilder builder = new QueryStringBuilder().appendParam("fields", fields);
      url =
          TASK_URL_TEMPLATE.buildWithQuery(
              this.getAPI().getBaseURL(), builder.toString(), this.getID());
    }
    BoxJSONRequest request = new BoxJSONRequest(this.getAPI(), url, "GET");
    try (BoxJSONResponse response = request.send()) {
      JsonObject responseJSON = Json.parse(response.getJSON()).asObject();
      return new Info(responseJSON);
    }
  }

  /**
   * Updates the information about this task with any info fields that have been modified locally.
   *
   * <p>The only fields that will be updated are the ones that have been modified locally. For
   * example, the following code won't update any information (or even send a network request) since
   * none of the info's fields were changed:
   *
   * <pre>BoxTask task = new BoxTask(api, id);
   * BoxTask.Info info = task.getInfo();
   * task.updateInfo(info);</pre>
   *
   * @param info the updated info.
   */
  public void updateInfo(BoxTask.Info info) {
    URL url = TASK_URL_TEMPLATE.build(this.getAPI().getBaseURL(), this.getID());
    BoxJSONRequest request = new BoxJSONRequest(this.getAPI(), url, "PUT");
    request.setBody(info.getPendingChanges());
    try (BoxJSONResponse response = request.send()) {
      JsonObject jsonObject = Json.parse(response.getJSON()).asObject();
      info.update(jsonObject);
    }
  }

  /** Enumerates the possible actions that a task can have. */
  public enum Action {
    /** The task must be reviewed. */
    REVIEW("review"),

    /** The task must be completed. */
    COMPLETE("complete");

    private final String jsonValue;

    Action(String jsonValue) {
      this.jsonValue = jsonValue;
    }

    static Action fromJSONString(String jsonValue) {
      if (jsonValue.equals("review")) {
        return REVIEW;
      } else if (jsonValue.equals("complete")) {
        return COMPLETE;
      } else {
        throw new IllegalArgumentException("The provided JSON value isn't a valid Action.");
      }
    }

    String toJSONString() {
      return this.jsonValue;
    }
  }

  /** Enumerates the possible completion rules for a task. */
  public enum CompletionRule {

    /** The task must be completed by all assignees. */
    ALL_ASSIGNEES("all_assignees"),

    /** The task must be completed by at least one assignee. */
    ANY_ASSIGNEE("any_assignee");

    private final String jsonValue;

    CompletionRule(String jsonValue) {
      this.jsonValue = jsonValue;
    }

    String toJSONString() {
      return this.jsonValue;
    }
  }

  /** Contains information about a BoxTask. */
  public class Info extends BoxResource.Info {
    private BoxFile.Info item;
    private Date dueAt;
    private String action;
    private String completionRule;
    private String message;
    private List<BoxTaskAssignment.Info> taskAssignments;
    private boolean completed;
    private BoxUser.Info createdBy;
    private Date createdAt;

    /** Constructs an empty Info object. */
    public Info() {
      super();
    }

    /**
     * Constructs an Info object by parsing information from a JSON string.
     *
     * @param json the JSON string to parse.
     */
    public Info(String json) {
      super(json);
    }

    /**
     * Constructs an Info object using an already parsed JSON object.
     *
     * @param jsonObject the parsed JSON object.
     */
    Info(JsonObject jsonObject) {
      super(jsonObject);
    }

    @Override
    public BoxTask getResource() {
      return BoxTask.this;
    }

    /**
     * Gets the file associated with this task.
     *
     * @return the file associated with this task.
     */
    public BoxFile.Info getItem() {
      return this.item;
    }

    /**
     * Gets the date at which this task is due.
     *
     * @return the date at which this task is due.
     */
    public Date getDueAt() {
      return this.dueAt;
    }

    /**
     * Sets the task's due date.
     *
     * @param dueAt the task's due date.
     */
    public void setDueAt(Date dueAt) {
      this.dueAt = dueAt;
      this.addPendingChange("due_at", BoxDateFormat.format(dueAt));
    }

    /**
     * Gets the action the task assignee will be prompted to do.
     *
     * @return the action the task assignee will be prompted to do.
     */
    public String getTaskType() {
      return this.action;
    }

    /**
     * Returns the completion rule for the task.
     *
     * @return the task completion rule.
     */
    public String getCompletionRule() {
      return this.completionRule;
    }

    /**
     * Sets the task's completion rule.
     *
     * @param completionRule the new completion rule.
     */
    public void setCompletionRule(CompletionRule completionRule) {
      this.completionRule = completionRule.toJSONString();
      this.addPendingChange("completion_rule", completionRule.toJSONString());
    }

    /**
     * Gets the message that will be included with this task.
     *
     * @return the message that will be included with this task.
     */
    public String getMessage() {
      return this.message;
    }

    /**
     * Sets the task's message.
     *
     * @param message the task's new message.
     */
    public void setMessage(String message) {
      this.message = message;
      this.addPendingChange("message", message);
    }

    /**
     * Gets the collection of task assignments associated with this task.
     *
     * @return the collection of task assignments associated with this task.
     */
    public List<BoxTaskAssignment.Info> getTaskAssignments() {
      return this.taskAssignments;
    }

    /**
     * Gets whether or not this task has been completed.
     *
     * @return whether or not this task has been completed.
     */
    public boolean isCompleted() {
      return this.completed;
    }

    /**
     * Gets the user who created this task.
     *
     * @return the user who created this task.
     */
    public BoxUser.Info getCreatedBy() {
      return this.createdBy;
    }

    /**
     * Gets when this task was created.
     *
     * @return when this task was created.
     */
    public Date getCreatedAt() {
      return this.createdAt;
    }

    @Override
    void parseJSONMember(JsonObject.Member member) {
      super.parseJSONMember(member);

      String memberName = member.getName();
      JsonValue value = member.getValue();
      try {
        switch (memberName) {
          case "item":
            JsonObject itemJSON = value.asObject();
            String itemID = itemJSON.get("id").asString();
            BoxFile file = new BoxFile(getAPI(), itemID);
            this.item = file.new Info(itemJSON);
            break;
          case "due_at":
            this.dueAt = BoxDateFormat.parse(value.asString());
            break;
          case "action":
            this.action = value.asString();
            break;
          case "completion_rule":
            this.completionRule = value.asString();
            break;
          case "message":
            this.message = value.asString();
            break;
          case "task_assignment_collection":
            this.taskAssignments = this.parseTaskAssignmentCollection(value.asObject());
            break;
          case "is_completed":
            this.completed = value.asBoolean();
            break;
          case "created_by":
            JsonObject userJSON = value.asObject();
            String userID = userJSON.get("id").asString();
            BoxUser user = new BoxUser(getAPI(), userID);
            this.createdBy = user.new Info(userJSON);
            break;
          case "created_at":
            this.createdAt = BoxDateFormat.parse(value.asString());
            break;
          default:
            break;
        }

      } catch (Exception e) {
        throw new BoxDeserializationException(memberName, value.toString(), e);
      }
    }

    private List<BoxTaskAssignment.Info> parseTaskAssignmentCollection(JsonObject jsonObject) {
      int count = jsonObject.get("total_count").asInt();
      List<BoxTaskAssignment.Info> taskAssignmentCollection = new ArrayList<>(count);
      JsonArray entries = jsonObject.get("entries").asArray();
      for (JsonValue value : entries) {
        JsonObject entry = value.asObject();
        String id = entry.get("id").asString();
        BoxTaskAssignment assignment = new BoxTaskAssignment(getAPI(), id);
        taskAssignmentCollection.add(assignment.new Info(entry));
      }

      return taskAssignmentCollection;
    }
  }
}