refactor selections (#876)

* migrate selection types

* extract selection event into selections.ts

* move code-mirror selection functions into selections.ts

* move more selection logit out of code mirror and engine connection

* add selection functions pure

* tidy up naming

* write a novel about how selections work

* final comments

src/useStore.ts

@@ -1,13 +1,8 @@
 import { create } from 'zustand'
 import { persist } from 'zustand/middleware'
 import { addLineHighlight, EditorView } from './editor/highlightextension'
-import {
-  parse,
-  Program,
-  _executor,
-  ProgramMemory,
-  SourceRange,
-} from './lang/wasm'
+import { parse, Program, _executor, ProgramMemory } from './lang/wasm'
+import { Selection, Selections, SelectionRangeTypeMap } from 'lib/selections'
 import { enginelessExecutor } from './lib/testHelpers'
 import { EditorSelection } from '@codemirror/state'
 import { EngineCommandManager } from './lang/std/engineConnection'
@@ -15,25 +10,6 @@ import { KCLError } from './lang/errors'
 import { kclManager } from 'lang/KclSinglton'
 import { DefaultPlanes } from './wasm-lib/kcl/bindings/DefaultPlanes'
 
-export type Axis = 'y-axis' | 'x-axis' | 'z-axis'
-
-export type Selection = {
-  type:
-    | 'default'
-    | 'line-end'
-    | 'line-mid'
-    | 'face'
-    | 'point'
-    | 'edge'
-    | 'line'
-    | 'arc'
-    | 'all'
-  range: SourceRange
-}
-export type Selections = {
-  otherSelections: Axis[]
-  codeBasedSelections: Selection[]
-}
 export type ToolTip =
   | 'lineTo'
   | 'line'
@@ -74,10 +50,6 @@ export type PaneType =
   | 'logs'
   | 'lspMessages'
 
-export interface SelectionRangeTypeMap {
-  [key: number]: Selection['type']
-}
-
 export interface StoreState {
   editorView: EditorView | null
   setEditorView: (editorView: EditorView) => void
@@ -342,79 +314,3 @@ export async function executeAst({
     }
   }
 }
-
-export function dispatchCodeMirrorCursor({
-  selections,
-  editorView,
-}: {
-  selections: Selections
-  editorView: EditorView
-}): {
-  selectionRangeTypeMap: SelectionRangeTypeMap
-} {
-  const ranges: ReturnType<typeof EditorSelection.cursor>[] = []
-  const selectionRangeTypeMap: SelectionRangeTypeMap = {}
-  selections.codeBasedSelections.forEach(({ range, type }) => {
-    if (range?.[1]) {
-      ranges.push(EditorSelection.cursor(range[1]))
-      selectionRangeTypeMap[range[1]] = type
-    }
-  })
-  setTimeout(() => {
-    ranges.length &&
-      editorView.dispatch({
-        selection: EditorSelection.create(
-          ranges,
-          selections.codeBasedSelections.length - 1
-        ),
-      })
-  })
-  return {
-    selectionRangeTypeMap,
-  }
-}
-
-export function setCodeMirrorCursor({
-  codeSelection,
-  currestSelections,
-  editorView,
-  isShiftDown,
-}: {
-  codeSelection?: Selection
-  currestSelections: Selections
-  editorView: EditorView
-  isShiftDown: boolean
-}): SelectionRangeTypeMap {
-  // This DOES NOT set the `selectionRanges` in xstate context
-  // instead it updates/dispatches to the editor, which in turn updates the xstate context
-  // I've found this the best way to deal with the editor without causing an infinite loop
-  // and really we want the editor to be in charge of cursor positions and for `selectionRanges` mirror it
-  // because we want to respect the user manually placing the cursor too.
-  const code = kclManager.code
-  if (!codeSelection) {
-    const { selectionRangeTypeMap } = dispatchCodeMirrorCursor({
-      editorView,
-      selections: {
-        otherSelections: currestSelections.otherSelections,
-        codeBasedSelections: [
-          {
-            range: [0, code.length ? code.length - 1 : 0],
-            type: 'default',
-          },
-        ],
-      },
-    })
-    return selectionRangeTypeMap
-  }
-  const selections: Selections = {
-    ...currestSelections,
-    codeBasedSelections: isShiftDown
-      ? [...currestSelections.codeBasedSelections, codeSelection]
-      : [codeSelection],
-  }
-  const { selectionRangeTypeMap } = dispatchCodeMirrorCursor({
-    editorView,
-    selections,
-  })
-  return selectionRangeTypeMap
-}