From a40bf95c413dd008a7c25f1b88a080a2fb434355 Mon Sep 17 00:00:00 2001
From: Andrew Kingston <aptkingston@ssl-mail.com>
Date: Wed, 6 Jan 2021 10:13:30 +0000
Subject: [PATCH] Enable selecting components from the builder preview and
 apply any custom styles

---
 .../client/src/components/ClientApp.svelte    |  1 +
 .../client/src/components/Component.svelte    | 12 ++-
 packages/client/src/components/Router.svelte  |  5 +-
 packages/client/src/utils/styleable.js        | 89 ++++++++++++++++---
 4 files changed, 93 insertions(+), 14 deletions(-)

diff --git a/packages/client/src/components/ClientApp.svelte b/packages/client/src/components/ClientApp.svelte
index a7a972a435..222344420e 100644
--- a/packages/client/src/components/ClientApp.svelte
+++ b/packages/client/src/components/ClientApp.svelte
@@ -9,6 +9,7 @@
   setContext("sdk", SDK)
   setContext("component", writable({}))
   setContext("data", createDataStore())
+  setContext("screenslot", false)
 
   let loaded = false
 
diff --git a/packages/client/src/components/Component.svelte b/packages/client/src/components/Component.svelte
index 56591133e5..23ba364dfb 100644
--- a/packages/client/src/components/Component.svelte
+++ b/packages/client/src/components/Component.svelte
@@ -8,8 +8,9 @@
 
   export let definition = {}
 
-  // Get local data binding context
+  // Get contexts
   const dataContext = getContext("data")
+  const screenslotContext = getContext("screenslot")
 
   // Create component context
   const componentStore = writable({})
@@ -20,10 +21,15 @@
   $: children = definition._children
   $: id = definition._id
   $: enrichedProps = enrichProps(definition, $dataContext, $bindingStore)
-  $: selected = id === $builderStore.selectedComponentId
+  $: styles = definition._styles
+
+  // Allow component selection in the builder preview if we're previewing a
+  // layout, or we're preview a screen and we're inside the screenslot
+  $: allowSelection =
+    $builderStore.previewType === "layout" || screenslotContext
 
   // Update component context
-  $: componentStore.set({ id, styles: { ...definition._styles, selected } })
+  $: componentStore.set({ id, styles: { ...styles, id, allowSelection } })
 
   // Gets the component constructor for the specified component
   const getComponentConstructor = component => {
diff --git a/packages/client/src/components/Router.svelte b/packages/client/src/components/Router.svelte
index 3c2d71c422..5477d02f86 100644
--- a/packages/client/src/components/Router.svelte
+++ b/packages/client/src/components/Router.svelte
@@ -1,5 +1,5 @@
 <script>
-  import { getContext } from "svelte"
+  import { getContext, setContext } from "svelte"
   import Router from "svelte-spa-router"
   import { routeStore } from "../store"
   import Screen from "./Screen.svelte"
@@ -7,6 +7,9 @@
   const { styleable } = getContext("sdk")
   const component = getContext("component")
 
+  // Set context flag so components know that we're now inside the screenslot
+  setContext("screenslot", true)
+
   // Only wrap this as an array to take advantage of svelte keying,
   // to ensure the svelte-spa-router is fully remounted when route config
   // changes
diff --git a/packages/client/src/utils/styleable.js b/packages/client/src/utils/styleable.js
index 4c6f8ca3b7..a3c4cb7ca5 100644
--- a/packages/client/src/utils/styleable.js
+++ b/packages/client/src/utils/styleable.js
@@ -1,49 +1,111 @@
+import { get } from "svelte/store"
+import { builderStore } from "../store"
+
+const selectedComponentWidth = 2
+const selectedComponentColor = "#4285f4"
+
 /**
- * Helper to build a CSS string from a style object
+ * Helper to build a CSS string from a style object.
  */
-const buildStyleString = (styleObject, customStyles, selected) => {
+const buildStyleString = (styleObject, customStyles) => {
   let str = ""
   Object.entries(styleObject).forEach(([style, value]) => {
     if (style && value != null) {
       str += `${style}: ${value}; `
     }
   })
-  str += customStyles || ""
-  if (selected) {
-    str += ";border: 2px solid #0055ff !important;"
+  return str + (customStyles || "")
+}
+
+/**
+ * Applies styles to enrich the builder preview.
+ * Applies styles to highlight the selected component, and allows pointer
+ * events for any selectable components (overriding the blanket ban on pointer
+ * events in the iframe HTML).
+ */
+const addBuilderPreviewStyles = (styleString, componentId, selectable) => {
+  let str = styleString
+
+  // Apply extra styles if we're in the builder preview
+  const state = get(builderStore)
+  if (state.inBuilder) {
+    // Allow pointer events and always enable cursor
+    if (selectable) {
+      str += ";pointer-events: all !important; cursor: pointer !important;"
+    }
+
+    // Highlighted selected element
+    if (componentId === state.selectedComponentId) {
+      str += `;box-shadow: 0 0 0 ${selectedComponentWidth}px ${selectedComponentColor} inset !important;`
+    }
   }
+
   return str
 }
 
 /**
  * Svelte action to apply correct component styles.
+ * This also applies handlers for selecting components from the builder preview.
  */
 export const styleable = (node, styles = {}) => {
   let applyNormalStyles
   let applyHoverStyles
+  let selectComponent
+
+  // Kill JS even bubbling
+  const blockEvent = event => {
+    event.preventDefault()
+    event.stopPropagation()
+    return false
+  }
 
   // Creates event listeners and applies initial styles
   const setupStyles = newStyles => {
-    const selected = newStyles.selected
+    const componentId = newStyles.id
+    const selectable = newStyles.allowSelection
     const customStyles = newStyles.custom
-    const normalStyles = newStyles.normal || {}
+    const normalStyles = newStyles.normal
     const hoverStyles = {
       ...normalStyles,
       ...newStyles.hover,
     }
 
-    applyNormalStyles = () => {
-      node.style = buildStyleString(normalStyles, customStyles, selected)
+    // Applies a style string to a DOM node, enriching it for the builder
+    // preview
+    const applyStyles = styleString => {
+      node.style = addBuilderPreviewStyles(styleString, componentId, selectable)
     }
 
+    // Applies the "normal" style definition
+    applyNormalStyles = () => {
+      applyStyles(buildStyleString(normalStyles, customStyles))
+    }
+
+    // Applies any "hover" styles as well as the base "normal" styles
     applyHoverStyles = () => {
-      node.style = buildStyleString(hoverStyles, customStyles, selected)
+      applyStyles(buildStyleString(hoverStyles, customStyles))
+    }
+
+    // Handler to select a component in the builder when clicking it in the
+    // builder preview
+    selectComponent = event => {
+      builderStore.actions.selectComponent(newStyles.id)
+      return blockEvent(event)
     }
 
     // Add listeners to toggle hover styles
     node.addEventListener("mouseover", applyHoverStyles)
     node.addEventListener("mouseout", applyNormalStyles)
 
+    // Add builder preview click listener
+    if (get(builderStore).inBuilder) {
+      node.addEventListener("click", selectComponent, false)
+
+      // Kill other interaction events
+      node.addEventListener("mousedown", blockEvent)
+      node.addEventListener("mouseup", blockEvent)
+    }
+
     // Apply initial normal styles
     applyNormalStyles()
   }
@@ -52,6 +114,13 @@ export const styleable = (node, styles = {}) => {
   const removeListeners = () => {
     node.removeEventListener("mouseover", applyHoverStyles)
     node.removeEventListener("mouseout", applyNormalStyles)
+
+    // Remove builder preview click listener
+    if (get(builderStore).inBuilder) {
+      node.removeEventListener("click", selectComponent)
+      node.removeEventListener("mousedown", blockEvent)
+      node.removeEventListener("mouseup", blockEvent)
+    }
   }
 
   // Apply initial styles