From 0f4a184e0f2eadfe062bb2e8e189cb46fb80def3 Mon Sep 17 00:00:00 2001
From: Yuto Tachibana <tachibanayu24@gmail.com>
Date: Thu, 19 Aug 2021 00:11:22 +0900
Subject: [PATCH] fix: signavio#498 support IME with input hint along

---
 src/utils/applyChangeToValue.js      | 20 +++++--
 src/utils/applyChangeToValue.spec.js | 79 ++++++++++++++++++++++++++--
 2 files changed, 91 insertions(+), 8 deletions(-)

diff --git a/src/utils/applyChangeToValue.js b/src/utils/applyChangeToValue.js
index 670283e3..3c358d62 100644
--- a/src/utils/applyChangeToValue.js
+++ b/src/utils/applyChangeToValue.js
@@ -60,16 +60,26 @@ const applyChangeToValue = (
 
       // find start of diff
       spliceStart = 0
-      while (plainTextValue[spliceStart] === controlPlainTextValue[spliceStart])
+      while (plainTextValue[spliceStart] === oldPlainTextValue[spliceStart])
         spliceStart++
 
+      // find end of diff
+      let spliceEndOfNew = plainTextValue.length
+      let spliceEndOfOld = oldPlainTextValue.length
+      while (
+        plainTextValue[spliceEndOfNew - 1] ===
+        oldPlainTextValue[spliceEndOfOld - 1]
+      ) {
+        spliceEndOfNew--
+        spliceEndOfOld--
+      }
+
       // extract auto-corrected insertion
-      insert = plainTextValue.slice(spliceStart, selectionEndAfter)
+      insert = plainTextValue.slice(spliceStart, spliceEndOfNew)
 
       // find index of the unchanged remainder
-      spliceEnd = oldPlainTextValue.lastIndexOf(
-        plainTextValue.substring(selectionEndAfter)
-      )
+      spliceEnd =
+        spliceEndOfOld >= spliceStart ? spliceEndOfOld : selectionEndAfter
 
       // re-map the corrected indices
       mappedSpliceStart = mapPlainTextIndex(value, config, spliceStart, 'START')
diff --git a/src/utils/applyChangeToValue.spec.js b/src/utils/applyChangeToValue.spec.js
index 06f6850e..896e7366 100644
--- a/src/utils/applyChangeToValue.spec.js
+++ b/src/utils/applyChangeToValue.spec.js
@@ -23,7 +23,7 @@ describe('#applyChangeToValue', () => {
   const plainText =
     "Hi John Doe, \n\nlet's add joe@smoe.com to this conversation..."
 
-  const displayTransform = id => `<--${id}-->`
+  const displayTransform = (id) => `<--${id}-->`
   const plainTextDisplayTransform =
     "Hi <--johndoe-->, \n\nlet's add <--joe@smoe.com--> to this conversation..."
 
@@ -70,6 +70,50 @@ describe('#applyChangeToValue', () => {
     )
   })
 
+  it('should correctly add characters with cursor in the middle at the end, beginning, and in the middle of text', () => {
+    let changed = 'S[start]' + plainText
+    let result = applyChangeToValue(
+      value,
+      changed,
+      {
+        selectionStartBefore: 0,
+        selectionEndBefore: 0,
+        selectionEndAfter: 1,
+      },
+      config
+    )
+    expect(result).toEqual('S[start]' + value)
+
+    changed = plainText + 'E[end]'
+    result = applyChangeToValue(
+      value,
+      changed,
+      {
+        selectionStartBefore: plainText.length,
+        selectionEndBefore: plainText.length,
+        selectionEndAfter: plainText.length + 1,
+      },
+      config
+    )
+    expect(result).toEqual(value + 'E[end]')
+
+    changed =
+      "Hi John Doe, \n\nlet's M[mid]add joe@smoe.com to this conversation..."
+    result = applyChangeToValue(
+      value,
+      changed,
+      {
+        selectionStartBefore: 21,
+        selectionEndBefore: 21,
+        selectionEndAfter: 22,
+      },
+      config
+    )
+    expect(result).toEqual(
+      "Hi @[John Doe](user:johndoe), \n\nlet's M[mid]add @[joe@smoe.com](email:joe@smoe.com) to this conversation..."
+    )
+  })
+
   it('should correctly delete single characters and ranges of selected text', () => {
     // delete "i"
     let changed =
@@ -133,6 +177,20 @@ describe('#applyChangeToValue', () => {
       config
     )
     expect(result).toEqual(value.replace('add', 'remove'))
+
+    // replace range with cursor in the middle, eg. remove|[remove]
+    changed = plainText.replace('add', 'remove[remove]')
+    result = applyChangeToValue(
+      value,
+      changed,
+      {
+        selectionStartBefore: plainText.indexOf('add'),
+        selectionEndBefore: plainText.indexOf('add') + 'add'.length,
+        selectionEndAfter: plainText.indexOf('add') + 'remove'.length,
+      },
+      config
+    )
+    expect(result).toEqual(value.replace('add', 'remove[remove]'))
   })
 
   it('should remove mentions markup contained in deleted text ranges', () => {
@@ -249,7 +307,7 @@ describe('#applyChangeToValue', () => {
         selectionEndBefore: 26,
         selectionEndAfter: 26,
       },
-      config.map(c => ({ ...c, displayTransform }))
+      config.map((c) => ({ ...c, displayTransform }))
     )
     expect(result).toEqual(
       "Hi @[John Doe](user:johndoe), \n\nlet's dd @[joe@smoe.com](email:joe@smoe.com) to this conversation..."
@@ -257,7 +315,7 @@ describe('#applyChangeToValue', () => {
   })
 
   it('should correctly handle text auto-correction', () => {
-    const result = applyChangeToValue(
+    let result = applyChangeToValue(
       'ill',
       "I'll",
       {
@@ -268,5 +326,20 @@ describe('#applyChangeToValue', () => {
       config
     )
     expect(result).toEqual("I'll")
+
+    // case like
+    // input queue: s -> a -> d
+    // IME queue(| is the cursor position): s|[sa] -> s'a|[sa'a] -> sad|[sad]
+    result = applyChangeToValue(
+      "s'a[sa'a]",
+      'sad[sad]',
+      {
+        selectionStartBefore: 2,
+        selectionEndBefore: 2,
+        selectionEndAfter: 3,
+      },
+      config
+    )
+    expect(result).toEqual('sad[sad]')
   })
 })