feat(desktop): unify folder drag-and-drop across runtimes

packages/ui/src/lib/hooks/use-folder-drop.ts

@@ -0,0 +1,158 @@
+import { Accessor, createEffect, createSignal, onCleanup, onMount } from "solid-js"
+import {
+  containsFileDrop,
+  extractDroppedDirectoryPaths,
+  listenForNativeFolderDrops,
+  listenForNativeFolderDropState,
+  normalizeDroppedDirectoryPaths,
+  supportsDesktopFolderDrop,
+} from "../native/desktop-file-drop"
+import { runtimeEnv } from "../runtime-env"
+
+interface UseFolderDropOptions {
+  enabled: Accessor<boolean>
+  onDrop: (paths: string[]) => void | Promise<void>
+  onInvalidDrop?: () => void
+}
+
+interface FolderDropBindings {
+  onDragEnter: (event: DragEvent) => void
+  onDragOver: (event: DragEvent) => void
+  onDragLeave: (event: DragEvent) => void
+  onDrop: (event: DragEvent) => void
+}
+
+export function useFolderDrop(options: UseFolderDropOptions): {
+  isActive: Accessor<boolean>
+  isSupported: boolean
+  bind: FolderDropBindings
+} {
+  const [isActive, setIsActive] = createSignal(false)
+  const [dragDepth, setDragDepth] = createSignal(0)
+  const isSupported = supportsDesktopFolderDrop()
+
+  function reset() {
+    setDragDepth(0)
+    setIsActive(false)
+  }
+
+  async function handleResolvedPaths(paths: string[]) {
+    reset()
+    if (!options.enabled()) {
+      return
+    }
+    const directoryPaths = await normalizeDroppedDirectoryPaths(paths)
+    if (directoryPaths.length === 0) {
+      options.onInvalidDrop?.()
+      return
+    }
+    await options.onDrop(directoryPaths)
+  }
+
+  createEffect(() => {
+    if (!options.enabled()) {
+      reset()
+    }
+  })
+
+  onMount(() => {
+    if (!isSupported) {
+      return
+    }
+
+    let disposeNativeDrop = () => {}
+    let disposeNativeState = () => {}
+
+    void listenForNativeFolderDrops((paths) => {
+      if (!options.enabled()) {
+        return
+      }
+      void handleResolvedPaths(paths)
+    }).then((dispose) => {
+      disposeNativeDrop = dispose
+    })
+
+    void listenForNativeFolderDropState((state) => {
+      if (!options.enabled()) {
+        reset()
+        return
+      }
+      if (state === "enter") {
+        setIsActive(true)
+        return
+      }
+      reset()
+    }).then((dispose) => {
+      disposeNativeState = dispose
+    })
+
+    onCleanup(() => {
+      disposeNativeDrop()
+      disposeNativeState()
+    })
+  })
+
+  const bind: FolderDropBindings = {
+    onDragEnter(event) {
+      if (!isSupported || runtimeEnv.host === "tauri" || !options.enabled() || !containsFileDrop(event)) {
+        return
+      }
+      event.preventDefault()
+      setDragDepth((prev) => prev + 1)
+      setIsActive(true)
+    },
+    onDragOver(event) {
+      if (!isSupported || runtimeEnv.host === "tauri" || !options.enabled() || !containsFileDrop(event)) {
+        return
+      }
+      event.preventDefault()
+      if (event.dataTransfer) {
+        event.dataTransfer.dropEffect = "copy"
+      }
+      setIsActive(true)
+    },
+    onDragLeave(event) {
+      if (!isSupported || runtimeEnv.host === "tauri" || !containsFileDrop(event)) {
+        return
+      }
+      event.preventDefault()
+      const nextDepth = Math.max(0, dragDepth() - 1)
+      setDragDepth(nextDepth)
+      if (nextDepth === 0) {
+        setIsActive(false)
+      }
+    },
+    onDrop(event) {
+      if (!isSupported) {
+        return
+      }
+      event.preventDefault()
+      event.stopPropagation()
+
+      if (!options.enabled()) {
+        reset()
+        return
+      }
+
+      if (runtimeEnv.host === "tauri") {
+        reset()
+        return
+      }
+
+      const paths = extractDroppedDirectoryPaths(event)
+      if (paths.length === 0) {
+        reset()
+        options.onInvalidDrop?.()
+        return
+      }
+
+      void handleResolvedPaths(paths)
+    },
+  }
+
+  return {
+    isActive,
+    isSupported,
+    bind,
+  }
+}