From 9999ef643ffe3ee953c675aa05b62705a2f45266 Mon Sep 17 00:00:00 2001
From: Zachary Yedidia <zyedidia@gmail.com>
Date: Sat, 15 Aug 2020 18:17:57 -0400
Subject: [PATCH] Use delta instead of textedit

---
 internal/buffer/autocomplete.go | 33 ++++++++++++++++-----------------
 internal/buffer/buffer.go       | 16 ++++++++++++++++
 internal/buffer/eventhandler.go |  6 ++++++
 3 files changed, 38 insertions(+), 17 deletions(-)

diff --git a/internal/buffer/autocomplete.go b/internal/buffer/autocomplete.go
index 135637a5..4a5817ed 100644
--- a/internal/buffer/autocomplete.go
+++ b/internal/buffer/autocomplete.go
@@ -9,7 +9,6 @@ import (
 
 	"github.com/zyedidia/micro/v2/internal/lsp"
 	"github.com/zyedidia/micro/v2/internal/util"
-	"go.lsp.dev/protocol"
 )
 
 // A Completer is a function that takes a buffer and returns info
@@ -22,7 +21,7 @@ import (
 type Completer func(*Buffer) []Completion
 
 type Completion struct {
-	Edits       []protocol.TextEdit
+	Edits       []Delta
 	Label       string
 	CommitChars []rune
 	Kind        int
@@ -67,7 +66,7 @@ func (b *Buffer) CycleAutocomplete(forward bool) {
 
 	// apply current completion
 	comp := b.Completions[b.CurCompletion]
-	b.ApplyEdits(comp.Edits)
+	b.ApplyDeltas(comp.Edits)
 	if len(b.Completions) > 1 {
 		b.HasSuggestions = true
 	}
@@ -234,7 +233,11 @@ func LSPComplete(b *Buffer) []Completion {
 		}
 
 		if item.TextEdit != nil && len(item.TextEdit.NewText) > 0 {
-			completions[i].Edits = []protocol.TextEdit{*item.TextEdit}
+			completions[i].Edits = []Delta{Delta{
+				Text:  []byte(item.TextEdit.NewText),
+				Start: toLoc(item.TextEdit.Range.Start),
+				End:   toLoc(item.TextEdit.Range.End),
+			}}
 		} else {
 			var t string
 			if len(item.InsertText) > 0 {
@@ -243,13 +246,11 @@ func LSPComplete(b *Buffer) []Completion {
 				t = item.Label
 			}
 			_, argstart := GetWord(b)
-			str := util.SliceEndStr(t, c.X-argstart)
-			completions[i].Edits = []protocol.TextEdit{protocol.TextEdit{
-				NewText: str,
-				Range: protocol.Range{
-					Start: lsp.Position(c.X, c.Y),
-					End:   lsp.Position(c.X, c.Y),
-				},
+			str := util.SliceEnd([]byte(t), c.X-argstart)
+			completions[i].Edits = []Delta{Delta{
+				Text:  str,
+				Start: Loc{c.X, c.Y},
+				End:   Loc{c.X, c.Y},
 			}}
 		}
 	}
@@ -266,12 +267,10 @@ func ConvertCompletions(completions, suggestions []string, c *Cursor) []Completi
 		comp[i] = Completion{
 			Label: suggestions[i],
 		}
-		comp[i].Edits = []protocol.TextEdit{protocol.TextEdit{
-			NewText: completions[i],
-			Range: protocol.Range{
-				Start: lsp.Position(c.X, c.Y),
-				End:   lsp.Position(c.X, c.Y),
-			},
+		comp[i].Edits = []Delta{Delta{
+			Text:  []byte(completions[i]),
+			Start: Loc{c.X, c.Y},
+			End:   Loc{c.X, c.Y},
 		}}
 	}
 	return comp
diff --git a/internal/buffer/buffer.go b/internal/buffer/buffer.go
index 9de39d95..bd0285e1 100644
--- a/internal/buffer/buffer.go
+++ b/internal/buffer/buffer.go
@@ -553,6 +553,22 @@ func (b *Buffer) ApplyEdits(edits []lspt.TextEdit) {
 	}
 }
 
+func (b *Buffer) ApplyDeltas(deltas []Delta) {
+	if !b.Type.Readonly {
+		sort.Slice(deltas, func(i, j int) bool {
+			return deltas[i].Start.GreaterThan(deltas[j].Start)
+		})
+		for _, d := range deltas {
+			if len(d.Text) == 0 {
+				b.Remove(d.Start, d.End)
+			} else {
+				b.ReplaceBytes(d.Start, d.End, d.Text)
+			}
+		}
+		b.RelocateCursors()
+	}
+}
+
 // FileType returns the buffer's filetype
 func (b *Buffer) FileType() string {
 	return b.Settings["filetype"].(string)
diff --git a/internal/buffer/eventhandler.go b/internal/buffer/eventhandler.go
index 3862d696..94957c04 100644
--- a/internal/buffer/eventhandler.go
+++ b/internal/buffer/eventhandler.go
@@ -230,6 +230,12 @@ func (eh *EventHandler) Replace(start, end Loc, replace string) {
 	eh.Insert(start, replace)
 }
 
+// ReplaceBytes deletes from start to end and replaces it with the given string
+func (eh *EventHandler) ReplaceBytes(start, end Loc, replace []byte) {
+	eh.Remove(start, end)
+	eh.InsertBytes(start, replace)
+}
+
 // Execute a textevent and add it to the undo stack
 func (eh *EventHandler) Execute(t *TextEvent) {
 	if eh.RedoStack.Len() > 0 {