From 554bf41d507cc40f8dd140e8f408c1680a68b4ec Mon Sep 17 00:00:00 2001
From: Victor Lin <13424970+victorlin@users.noreply.github.com>
Date: Wed, 18 Oct 2023 15:59:30 -0700
Subject: [PATCH] Add ability to show/hide options when panel is on

---
 src/components/controls/panelChevron.tsx | 25 ++++++++++++++++++
 src/components/controls/panelHeader.tsx  | 33 ++++++++++++++++++++----
 src/components/controls/panelSection.tsx | 13 +++++++++-
 3 files changed, 65 insertions(+), 6 deletions(-)
 create mode 100644 src/components/controls/panelChevron.tsx

diff --git a/src/components/controls/panelChevron.tsx b/src/components/controls/panelChevron.tsx
new file mode 100644
index 000000000..520a99fce
--- /dev/null
+++ b/src/components/controls/panelChevron.tsx
@@ -0,0 +1,25 @@
+import React from "react";
+import styled from 'styled-components';
+import { FaChevronRight, FaChevronDown } from "react-icons/fa";
+
+const Container = styled.span`
+  padding-right: 6px;
+  color: ${(props) => props.theme.color};
+`
+
+type Props = {
+  show: boolean
+}
+
+/**
+ * An interactive chevron to show/hide a panel's options.
+ */
+export const PanelChevron = ({ show }: Props) => {
+  const icon = show ? <FaChevronDown /> : <FaChevronRight />
+
+  return (
+    <Container>
+      {icon}
+    </Container>
+  )
+}
diff --git a/src/components/controls/panelHeader.tsx b/src/components/controls/panelHeader.tsx
index faa1cd100..15ace4626 100644
--- a/src/components/controls/panelHeader.tsx
+++ b/src/components/controls/panelHeader.tsx
@@ -2,6 +2,7 @@ import React from "react";
 import { HeaderContainer } from "./styles";
 import { PanelToggle, Panel, On } from "./panelToggle";
 import { AnnotatedTitle, Mobile, Title, Tooltip } from "./annotatedTitle";
+import { PanelChevron } from "./panelChevron";
 
 type Props = {
   panel: Panel
@@ -9,18 +10,40 @@ type Props = {
   tooltip?: Tooltip
   panelIsVisible: On
   mobile: Mobile
+
+  /** Indicates whether there are options for the panel. */
+  hasOptions: boolean
+
+  /** Indicates options visibility. */
+  optionsAreVisible: boolean
+
+  /** Update options visibility. */
+  setOptionsAreVisible: React.Dispatch<React.SetStateAction<boolean>>
 }
 
 /**
  * A header used by all panel controls, containing an interactive title.
  */
-export const PanelHeader = ({ panel, title, tooltip, panelIsVisible, mobile }: Props) => {
+export const PanelHeader = ({ panel, title, tooltip, panelIsVisible, hasOptions, optionsAreVisible, setOptionsAreVisible, mobile }: Props) => {
+
+  let titleContainerProps = {}
+
+  if (hasOptions) {
+    titleContainerProps = {
+      role: "button",
+      onClick: () => setOptionsAreVisible(!optionsAreVisible),
+    }
+  }
+
   return (
     <HeaderContainer>
-      <AnnotatedTitle
-        title={title}
-        tooltip={tooltip}
-        mobile={mobile} />
+      <span {...titleContainerProps}>
+        {hasOptions && <PanelChevron show={optionsAreVisible} />}
+        <AnnotatedTitle
+          title={title}
+          tooltip={tooltip}
+          mobile={mobile} />
+      </span>
       <PanelToggle
         panel={panel}
         on={panelIsVisible} />
diff --git a/src/components/controls/panelSection.tsx b/src/components/controls/panelSection.tsx
index 173a67ef1..019e796a3 100644
--- a/src/components/controls/panelSection.tsx
+++ b/src/components/controls/panelSection.tsx
@@ -25,6 +25,14 @@ export const PanelSection = ({ panel, title, tooltip, options=undefined, mobile
 
   const panelIsVisible = panelsToDisplay.includes(panel)
 
+  // Initially, panel visibility determines options visibility.
+  const [optionsAreVisible, setOptionsAreVisible] = React.useState(panelIsVisible);
+
+  // Subsequent panel visibility updates also determines options visibility.
+  React.useEffect(() => {
+    setOptionsAreVisible(panelIsVisible)
+  }, [panelIsVisible])
+
   return (
     <PanelSectionContainer>
       <PanelHeader
@@ -33,8 +41,11 @@ export const PanelSection = ({ panel, title, tooltip, options=undefined, mobile
         tooltip={tooltip}
         panelIsVisible={panelIsVisible}
         mobile={mobile}
+        hasOptions={options!==undefined}
+        optionsAreVisible={optionsAreVisible}
+        setOptionsAreVisible={setOptionsAreVisible}
       />
-      {panelIsVisible && options}
+      {optionsAreVisible && options}
     </PanelSectionContainer>
   );
 };