From aaa33acc1c2ada8c44412e872ab42cc33497856a Mon Sep 17 00:00:00 2001
From: Andrew Kingston <andrew@kingston.dev>
Date: Fri, 9 Aug 2024 18:04:23 +0100
Subject: [PATCH] Rework grid layouts to automatically grow as required

---
 .../app/container/GridContainer.svelte        | 169 ++++++++++++------
 .../components/preview/GridDNDHandler.svelte  |  66 ++++---
 packages/client/src/constants.js              |   3 +
 packages/client/src/utils/grid.js             |  24 ++-
 4 files changed, 183 insertions(+), 79 deletions(-)

diff --git a/packages/client/src/components/app/container/GridContainer.svelte b/packages/client/src/components/app/container/GridContainer.svelte
index 8e8621c1a6..d97e7ceafb 100644
--- a/packages/client/src/components/app/container/GridContainer.svelte
+++ b/packages/client/src/components/app/container/GridContainer.svelte
@@ -1,50 +1,136 @@
 <script>
-  import { getContext } from "svelte"
+  import { getContext, onMount } from "svelte"
+  import { writable } from "svelte/store"
+  import { GridRowHeight, GridColumns } from "constants"
 
   const component = getContext("component")
-  const { styleable } = getContext("sdk")
+  const { styleable, builderStore } = getContext("sdk")
   const context = getContext("context")
 
-  const cols = 12
-  const rowHeight = 24
-
   let width
-  let height
+  let ref
+  let rows = 1
+  let children = writable({})
+  let mounted = false
 
+  $: rows = calculateRequiredRows($children, mobile)
   $: mobile = $context.device.mobile
   $: empty = $component.empty
-  $: rows = Math.max(1, Math.floor(height / rowHeight))
-  $: colSize = width / cols
-  $: rowSize = height / rows
+  $: colSize = width / GridColumns
+  $: height = rows * GridRowHeight
+
+  // Calculates the minimum number of rows required to render all child
+  // components, on a certain device type
+  const calculateRequiredRows = (children, mobile) => {
+    const key = mobile ? "mobileRowEnd" : "desktopRowEnd"
+    let max = 2
+    for (let id of Object.keys(children)) {
+      if (children[id][key] > max) {
+        max = children[id][key]
+      }
+    }
+    return max - 1
+  }
+
+  // Stores metadata about a child node as constraints for determining grid size
+  const storeChild = node => {
+    children.update(state => ({
+      ...state,
+      [node.dataset.id]: {
+        desktopRowEnd: parseInt(node.dataset.gridDesktopRowEnd),
+        mobileRowEnd: parseInt(node.dataset.gridMobileRowEnd),
+      },
+    }))
+  }
+
+  // Removes constraint metadata for a certain child node
+  const removeChild = node => {
+    children.update(state => {
+      delete state[node.dataset.id]
+      return { ...state }
+    })
+  }
+
+  onMount(() => {
+    let observer
+    if ($builderStore.inBuilder) {
+      // Set up an observer to watch for changes in metadata attributes of child
+      // components, as well as child addition and deletion
+      observer = new MutationObserver(mutations => {
+        for (let mutation of mutations) {
+          const { target, type, addedNodes, removedNodes } = mutation
+          if (target === ref) {
+            if (addedNodes[0]?.classList?.contains("component")) {
+              // We've added a new child component inside the grid, so we need
+              // to consider it when determining required rows
+              storeChild(addedNodes[0])
+            } else if (removedNodes[0]?.classList?.contains("component")) {
+              // We've removed a child component inside the grid, so we need
+              // to stop considering it when determining required rows
+              removeChild(removedNodes[0])
+            }
+          } else if (
+            type === "attributes" &&
+            target.parentNode === ref &&
+            target.classList.contains("component")
+          ) {
+            // We've updated the size or position of a child
+            storeChild(target)
+          }
+        }
+      })
+      observer.observe(ref, {
+        childList: true,
+        attributes: true,
+        subtree: true,
+        attributeFilter: [
+          "data-grid-desktop-row-end",
+          "data-grid-mobile-row-end",
+        ],
+      })
+    }
+
+    // Now that the observer is set up, we mark the grid as mounted to mount
+    // our child components
+    mounted = true
+
+    // Cleanup our observer
+    return () => {
+      observer?.disconnect()
+    }
+  })
 </script>
 
 <div
+  bind:this={ref}
   class="grid"
   class:mobile
   bind:clientWidth={width}
-  bind:clientHeight={height}
   use:styleable={{
     ...$component.styles,
     normal: {
       ...$component.styles?.normal,
-      "--cols": cols,
+      "--height": `${height}px`,
+      "--cols": GridColumns,
       "--rows": rows,
       "--col-size": colSize,
-      "--row-size": rowSize,
+      "--row-size": GridRowHeight,
     },
     empty: false,
   }}
-  data-rows={rows}
-  data-cols={cols}
+  data-cols={GridColumns}
+  data-col-size={colSize}
 >
-  <div class="underlay">
-    {#each { length: cols * rows } as _}
-      <div class="placeholder" />
-    {/each}
-  </div>
+  {#if $builderStore.inBuilder}
+    <div class="underlay">
+      {#each { length: GridColumns * rows } as _, idx}
+        <div class="placeholder" class:first-col={idx % GridColumns === 0} />
+      {/each}
+    </div>
+  {/if}
 
   <!-- Only render the slot if not empty, as we don't want the placeholder -->
-  {#if !empty}
+  {#if !empty && mounted}
     <slot />
   {/if}
 </div>
@@ -52,7 +138,6 @@
 <style>
   .grid {
     position: relative;
-    height: 400px;
 
     /*
       Prevent cross-grid variable inheritance. The other variables for alignment
@@ -71,8 +156,11 @@
 
   .grid,
   .underlay {
+    height: var(--height) !important;
+    min-height: none !important;
+    max-height: none !important;
     display: grid;
-    grid-template-rows: repeat(var(--rows), 1fr);
+    grid-template-rows: repeat(var(--rows), calc(var(--row-size) * 1px));
     grid-template-columns: repeat(var(--cols), 1fr);
     gap: 0;
   }
@@ -84,7 +172,6 @@
     width: 100%;
     height: 100%;
     border-top: 1px solid var(--spectrum-global-color-gray-900);
-    border-left: 1px solid var(--spectrum-global-color-gray-900);
     opacity: 0.1;
     pointer-events: none;
   }
@@ -95,6 +182,9 @@
     border-bottom: 1px solid var(--spectrum-global-color-gray-900);
     border-right: 1px solid var(--spectrum-global-color-gray-900);
   }
+  .placeholder.first-col {
+    border-left: 1px solid var(--spectrum-global-color-gray-900);
+  }
 
   /* Highlight grid lines when resizing children */
   :global(.grid.highlight > .underlay) {
@@ -131,20 +221,10 @@
         )
       )
     );
+
+    /* Row end is always provided by the gridLayout action */
     --row-start: var(--grid-desktop-row-start, var(--grid-mobile-row-start, 1));
-    --row-end: var(
-      --grid-desktop-row-end,
-      var(
-        --grid-mobile-row-end,
-        round(
-          up,
-          calc(
-            (var(--grid-spacing) * 2 + var(--default-height)) / var(--row-size) +
-              1
-          )
-        )
-      )
-    );
+    --row-end: var(--grid-desktop-row-end, var(--grid-mobile-row-end));
 
     /* Flex vars */
     --h-align: var(--grid-desktop-h-align, var(--grid-mobile-h-align));
@@ -156,8 +236,8 @@
       max(2, var(--col-end)),
       calc(var(--cols) + 1)
     ) !important;
-    grid-row-start: min(max(1, var(--row-start)), var(--rows)) !important;
-    grid-row-end: min(max(2, var(--row-end)), calc(var(--rows) + 1)) !important;
+    grid-row-start: max(1, var(--row-start)) !important;
+    grid-row-end: max(2, var(--row-end)) !important;
 
     /* Flex container styles */
     flex-direction: column;
@@ -182,18 +262,7 @@
       )
     );
     --row-start: var(--grid-mobile-row-start, var(--grid-desktop-row-start, 1));
-    --row-end: var(
-      --grid-mobile-row-end,
-      var(
-        --grid-desktop-row-end,
-        round(
-          up,
-          calc(
-            (var(--spacing) * 2 + var(--default-height)) / var(--row-size) + 1
-          )
-        )
-      )
-    );
+    --row-end: var(--grid-mobile-row-end, var(--grid-desktop-row-end));
 
     /* Flex vars */
     --h-align: var(--grid-mobile-h-align, var(--grid-desktop-h-align));
diff --git a/packages/client/src/components/preview/GridDNDHandler.svelte b/packages/client/src/components/preview/GridDNDHandler.svelte
index 0a3ecad72c..f7d0ba5437 100644
--- a/packages/client/src/components/preview/GridDNDHandler.svelte
+++ b/packages/client/src/components/preview/GridDNDHandler.svelte
@@ -2,6 +2,7 @@
   import { onMount, onDestroy } from "svelte"
   import { builderStore, componentStore } from "stores"
   import { Utils, memo } from "@budibase/frontend-core"
+  import { GridRowHeight } from "constants"
   import {
     isGridEvent,
     getGridParent,
@@ -15,8 +16,8 @@
     "data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw=="
 
   let dragInfo
+  let styles = memo()
   let gridStyles = memo()
-  let id
 
   // Grid CSS variables
   $: device = $builderStore.previewDevice
@@ -28,12 +29,14 @@
   }
 
   // Some memoisation of primitive types for performance
-  $: id = dragInfo?.id || id
+  $: id = dragInfo?.id
+  $: gridId = dragInfo?.gridId
 
-  // Set ephemeral grid styles on the dragged component
+  // Set ephemeral styles
   $: instance = componentStore.actions.getComponentInstance(id)
-  $: componentStyles = getComponentStyles($gridStyles)
-  $: $instance?.setEphemeralStyles(componentStyles)
+  $: gridInstance = componentStore.actions.getComponentInstance(gridId)
+  $: $instance?.setEphemeralStyles(enrichComponentStyles($styles))
+  $: $gridInstance?.setEphemeralStyles($gridStyles)
 
   // Sugar for a combination of both min and max
   const minMax = (value, min, max) => Math.min(max, Math.max(min, value))
@@ -44,47 +47,41 @@
     return Array.from(component?.children || [])[0]
   }
 
-  const getComponentStyles = gridStyles => {
-    let styles = { ...gridStyles }
-    if (gridStyles) {
-      styles["z-index"] = 999
-      styles["pointer-events"] = "none"
+  const enrichComponentStyles = styles => {
+    let clone = { ...styles }
+    if (styles) {
+      clone["z-index"] = 999
+      clone["pointer-events"] = "none"
     }
-    return styles
+    return clone
   }
 
   const processEvent = Utils.throttle((mouseX, mouseY) => {
     if (!dragInfo?.grid) {
       return
     }
-
     const { mode, side, gridId, grid } = dragInfo
     const { startX, startY, rowStart, rowEnd, colStart, colEnd } = grid
-
     const domGrid = getDOMNode(gridId)
     if (!domGrid) {
       return
     }
     const cols = parseInt(domGrid.dataset.cols)
-    const rows = parseInt(domGrid.dataset.rows)
-    const { width, height } = domGrid.getBoundingClientRect()
-
-    const colWidth = width / cols
+    const colSize = parseInt(domGrid.dataset.colSize)
     const diffX = mouseX - startX
-    let deltaX = Math.round(diffX / colWidth)
-    const rowHeight = height / rows
+    let deltaX = Math.round(diffX / colSize)
     const diffY = mouseY - startY
-    let deltaY = Math.round(diffY / rowHeight)
+    let deltaY = Math.round(diffY / GridRowHeight)
     if (mode === "move") {
       deltaX = minMax(deltaX, 1 - colStart, cols + 1 - colEnd)
-      deltaY = minMax(deltaY, 1 - rowStart, rows + 1 - rowEnd)
+      deltaY = Math.max(deltaY, 1 - rowStart)
       const newStyles = {
         [vars.colStart]: colStart + deltaX,
         [vars.colEnd]: colEnd + deltaX,
         [vars.rowStart]: rowStart + deltaY,
         [vars.rowEnd]: rowEnd + deltaY,
       }
-      gridStyles.set(newStyles)
+      styles.set(newStyles)
     } else if (mode === "resize") {
       let newStyles = {}
       if (side === "right") {
@@ -108,7 +105,7 @@
         newStyles[vars.colStart] = Math.min(colStart + deltaX, colEnd - 1)
         newStyles[vars.rowStart] = Math.min(rowStart + deltaY, rowEnd - 1)
       }
-      gridStyles.set(newStyles)
+      styles.set(newStyles)
     }
   }, 10)
 
@@ -180,15 +177,14 @@
       return
     }
     const gridCols = parseInt(domGrid.dataset.cols)
-    const gridRows = parseInt(domGrid.dataset.rows)
     const styles = getComputedStyle(domComponent.parentNode)
     dragInfo.grid = {
       startX: e.clientX,
       startY: e.clientY,
 
       // Ensure things are within limits
-      rowStart: minMax(styles["grid-row-start"], 1, gridRows),
-      rowEnd: minMax(styles["grid-row-end"], 2, gridRows + 1),
+      rowStart: Math.max(styles["grid-row-start"], 1),
+      rowEnd: Math.max(styles["grid-row-end"], 2),
       colStart: minMax(styles["grid-column-start"], 1, gridCols),
       colEnd: minMax(styles["grid-column-end"], 2, gridCols + 1),
     }
@@ -210,8 +206,11 @@
     const { id, gridId, domTarget } = dragInfo
 
     // Save changes
+    if ($styles) {
+      await builderStore.actions.updateStyles($styles, id)
+    }
     if ($gridStyles) {
-      await builderStore.actions.updateStyles($gridStyles, id)
+      await builderStore.actions.updateStyles($gridStyles, gridId)
     }
 
     // Reset DOM
@@ -227,9 +226,22 @@
 
     // Reset state
     dragInfo = null
+    styles.set(null)
     gridStyles.set(null)
   }
 
+  const calculateRequiredRows = () => {
+    let required = 1
+    const children = document.querySelectorAll(`.${gridId}-dom > .component`)
+    for (let child of children) {
+      const rowEnd = child.dataset.grid_desktop_col_end
+      if (rowEnd > required) {
+        required = rowEnd
+      }
+    }
+    return required - 1
+  }
+
   onMount(() => {
     document.addEventListener("dragstart", onDragStart, false)
     document.addEventListener("dragenter", onDragEnter, false)
diff --git a/packages/client/src/constants.js b/packages/client/src/constants.js
index d3f1ab8be9..f7e3e86d40 100644
--- a/packages/client/src/constants.js
+++ b/packages/client/src/constants.js
@@ -15,3 +15,6 @@ export const ActionTypes = {
 
 export const DNDPlaceholderID = "dnd-placeholder"
 export const ScreenslotType = "screenslot"
+export const GridRowHeight = 24
+export const GridColumns = 12
+export const GridSpacing = 4
diff --git a/packages/client/src/utils/grid.js b/packages/client/src/utils/grid.js
index d974e31899..72381d498d 100644
--- a/packages/client/src/utils/grid.js
+++ b/packages/client/src/utils/grid.js
@@ -1,3 +1,5 @@
+import { GridSpacing } from "constants"
+import { GridRowHeight } from "constants"
 import { builderStore } from "stores"
 import { buildStyleString } from "utils/styleable.js"
 
@@ -84,15 +86,23 @@ export const gridLayout = (node, metadata) => {
     }
 
     // Generate base set of grid CSS vars based for this component
+    let width = errored ? 500 : definition.size?.width || 200
+    let height = errored ? 60 : definition.size?.height || 200
+    width += 2 * GridSpacing
+    height += 2 * GridSpacing
     const hAlign = errored ? "stretch" : definition?.grid?.hAlign || "stretch"
     const vAlign = errored ? "stretch" : definition?.grid?.vAlign || "center"
     const vars = {
-      "--default-width": errored ? 500 : definition.size?.width || 200,
-      "--default-height": errored ? 60 : definition.size?.height || 200,
+      "--default-width": width,
+      "--default-height": height,
       "--grid-desktop-h-align": hAlign,
       "--grid-mobile-h-align": hAlign,
       "--grid-desktop-v-align": vAlign,
       "--grid-mobile-v-align": vAlign,
+
+      // Variables for automatically determining grid height
+      "--grid-desktop-row-end": Math.ceil(height / GridRowHeight) + 1,
+      "--grid-mobile-row-end": Math.ceil(height / GridRowHeight) + 1,
     }
 
     // Extract any other CSS variables from the saved component styles
@@ -103,6 +113,16 @@ export const gridLayout = (node, metadata) => {
       }
     }
 
+    // Apply some metadata to data attributes to speed up lookups
+    const desktopRowEnd = `${vars["--grid-desktop-row-end"]}`
+    const mobileRowEnd = `${vars["--grid-mobile-row-end"]}`
+    if (node.dataset.gridDesktopRowEnd !== desktopRowEnd) {
+      node.dataset.gridDesktopRowEnd = desktopRowEnd
+    }
+    if (node.dataset.gridMobileRowEnd !== mobileRowEnd) {
+      node.dataset.gridMobileRowEnd = mobileRowEnd
+    }
+
     // Apply all CSS variables to the wrapper
     node.style = buildStyleString(vars)