Add Android support for Timeline detail view

Summary:
This diff adds the Java classes that serialize to the data expected by the new timeline widget. See D23865369 for the JS counterpart.

Currently the Flipper plugin uses `toString` to get the wire values. I'm not feeling like using a json library or dealing with JSONObject's nonsense, so these are rolled manually for now.

Reviewed By: astreet

Differential Revision: D24254377

fbshipit-source-id: b2fc00400c40b47ac29c9b83c0b66621c3677974

android/src/main/java/com/facebook/flipper/plugins/inspector/InspectorValue.java

@@ -9,7 +9,14 @@ package com.facebook.flipper.plugins.inspector;
 
 import com.facebook.flipper.core.FlipperObject;
 import com.facebook.flipper.core.FlipperValue;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Map;
 import java.util.Set;
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
 
 public class InspectorValue<T> implements FlipperValue {
 
@@ -30,6 +37,7 @@ public class InspectorValue<T> implements FlipperValue {
     public static final Type<String> Enum = new Type<>("enum");
     public static final Type<Integer> Color = new Type<>("color");
     public static final Type<Picker> Picker = new Type<>("picker");
+    public static final Type<Timeline> Timeline = new Type<>("timeline");
 
     private final String mName;
 
@@ -108,4 +116,84 @@ public class InspectorValue<T> implements FlipperValue {
       return b.toString();
     }
   }
+
+  /**
+   * A widget that represents a timeline. Each point has a moment to be placed on the timeline, and
+   * a key to be identified as. The current field represents the key of the point in the timeline
+   * that matches the current moment in time.
+   */
+  public static final class Timeline {
+    public final List<TimePoint> time;
+    public final String current;
+
+    public Timeline(List<TimePoint> time, String current) {
+      Collections.sort(
+          time,
+          new Comparator<TimePoint>() {
+            @Override
+            public int compare(TimePoint stringTimePointEntry, TimePoint t1) {
+              return Float.compare(stringTimePointEntry.moment, t1.moment);
+            }
+          });
+      this.time = time;
+      this.current = current;
+    }
+
+    private JSONObject toJson() {
+      final JSONArray points = new JSONArray();
+      for (TimePoint value : time) {
+        points.put(value.toJson());
+      }
+      try {
+        return new JSONObject().put("time", points).put("current", current);
+      } catch (JSONException t) {
+        throw new RuntimeException(t);
+      }
+    }
+
+    @Override
+    public String toString() {
+      return toJson().toString();
+    }
+
+    /**
+     * An entry in the timeline, identified by its key. They're sorted in Flipper by moment, and are
+     * rendered according to the display and color. Any additional properties attached to the point
+     * will be displayed when it's selected.
+     */
+    public static final class TimePoint {
+      public final long moment;
+      public final String display;
+      public final String color;
+      public final String key;
+      public final Map<String, String> properties;
+
+      public TimePoint(
+          String key, long moment, String display, String color, Map<String, String> properties) {
+        this.key = key;
+        this.moment = moment;
+        this.display = display;
+        this.color = color;
+        this.properties = properties;
+      }
+
+      private JSONObject toJson() {
+        try {
+          return new JSONObject()
+              .put("moment", moment)
+              .put("display", display)
+              .put("color", color)
+              .put("key", key)
+              .put("properties", new JSONObject(properties));
+        } catch (JSONException t) {
+          throw new RuntimeException(t);
+        }
+      }
+
+      @Override
+      public String toString() {
+        return toJson().toString();
+      }
+    }
+  }
 }