implemented drag/drop for tabs

browser/components/SnippetTab.js

@@ -85,6 +85,19 @@ class SnippetTab extends React.Component {
     })
   }
 
+  handleDragStart (e) {
+    e.dataTransfer.dropEffect = 'move'
+    this.props.onDragStart(e)
+  }
+
+  handleDragEnd (e) {
+    this.props.onDragEnd(e)
+  }
+
+  handleDrop (e) {
+    this.props.onDrop(e)
+  }
+
   render () {
     const { isActive, snippet, isDeletable } = this.props
     return (
@@ -98,6 +111,10 @@ class SnippetTab extends React.Component {
             onClick={(e) => this.handleClick(e)}
             onDoubleClick={(e) => this.handleRenameClick(e)}
             onContextMenu={(e) => this.handleContextMenu(e)}
+            onDragStart={(e) => this.handleDragStart(e)}
+            onDragEnd={(e) => this.handleDragEnd(e)}
+            onDrop={(e) => this.handleDrop(e)}
+            draggable='true'
           >
             {snippet.name.trim().length > 0
               ? snippet.name
@@ -127,6 +144,7 @@ class SnippetTab extends React.Component {
 }
 
 SnippetTab.propTypes = {
+
 }
 
 export default CSSModules(SnippetTab, styles)

browser/main/Detail/SnippetNoteDetail.js

@@ -236,6 +236,26 @@ class SnippetNoteDetail extends React.Component {
     })
   }
 
+  handleTabDragStart (e, index) {
+    e.dataTransfer.setData('text/plain', index)
+  }
+
+  handleTabDrop (e, index) {
+    const oldIndex = parseInt(e.dataTransfer.getData('text'))
+
+    const snippets = this.state.note.snippets.slice()
+    const draggedSnippet = snippets[oldIndex]
+    snippets[oldIndex] = snippets[index]
+    snippets[index] = draggedSnippet
+    const snippetIndex = index
+
+    const note = Object.assign({}, this.state.note, {snippets})
+    this.setState({ note, snippetIndex }, () => {
+      this.save()
+      this.refs['code-' + this.state.snippetIndex].reload()
+    })
+  }
+
   handleTabDeleteButtonClick (e, index) {
     if (this.state.note.snippets.length > 1) {
       if (this.state.note.snippets[index].content.trim().length > 0) {
@@ -511,6 +531,8 @@ class SnippetNoteDetail extends React.Component {
         onDelete={(e) => this.handleTabDeleteButtonClick(e, index)}
         onRename={(name) => this.renameSnippetByIndex(index, name)}
         isDeletable={note.snippets.length > 1}
+        onDragStart={(e) => this.handleTabDragStart(e, index)}
+        onDrop={(e) => this.handleTabDrop(e, index)}
       />
     })