From e2079ac88e5391d5ac9a0e3d4559ec43c3611cc8 Mon Sep 17 00:00:00 2001
From: Zachary Yedidia <zyedidia@gmail.com>
Date: Thu, 9 Jun 2016 10:03:50 -0400
Subject: [PATCH] Add file completion to OpenFile (CtrlO) with tab

---
 cmd/micro/bindings.go  | 10 +++++-----
 cmd/micro/messenger.go | 43 +++++++++++++++++++++++++++++++++++++++---
 cmd/micro/view.go      |  2 +-
 3 files changed, 46 insertions(+), 9 deletions(-)

diff --git a/cmd/micro/bindings.go b/cmd/micro/bindings.go
index 18e2d6a1..22a3f3b3 100644
--- a/cmd/micro/bindings.go
+++ b/cmd/micro/bindings.go
@@ -731,7 +731,7 @@ func (v *View) Save() bool {
 	}
 	// If this is an empty buffer, ask for a filename
 	if v.Buf.Path == "" {
-		filename, canceled := messenger.Prompt("Filename: ", "Save")
+		filename, canceled := messenger.Prompt("Filename: ", "Save", NoCompletion)
 		if !canceled {
 			v.Buf.Path = filename
 			v.Buf.Name = filename
@@ -906,7 +906,7 @@ func (v *View) SelectAll() bool {
 // OpenFile opens a new file in the buffer
 func (v *View) OpenFile() bool {
 	if v.CanClose("Continue? (yes, no, save) ") {
-		filename, canceled := messenger.Prompt("File to open: ", "Open")
+		filename, canceled := messenger.Prompt("File to open: ", "Open", FileCompletion)
 		if canceled {
 			return false
 		}
@@ -1018,7 +1018,7 @@ func (v *View) ToggleRuler() bool {
 // JumpLine jumps to a line and moves the view accordingly.
 func (v *View) JumpLine() bool {
 	// Prompt for line number
-	linestring, canceled := messenger.Prompt("Jump to line # ", "LineNumber")
+	linestring, canceled := messenger.Prompt("Jump to line # ", "LineNumber", NoCompletion)
 	if canceled {
 		return false
 	}
@@ -1061,7 +1061,7 @@ func (v *View) ToggleHelp() bool {
 
 // ShellMode opens a terminal to run a shell command
 func (v *View) ShellMode() bool {
-	input, canceled := messenger.Prompt("$ ", "Shell")
+	input, canceled := messenger.Prompt("$ ", "Shell", NoCompletion)
 	if !canceled {
 		// The true here is for openTerm to make the command interactive
 		HandleShellCommand(input, true)
@@ -1071,7 +1071,7 @@ func (v *View) ShellMode() bool {
 
 // CommandMode lets the user enter a command
 func (v *View) CommandMode() bool {
-	input, canceled := messenger.Prompt("> ", "Command")
+	input, canceled := messenger.Prompt("> ", "Command", NoCompletion)
 	if !canceled {
 		HandleCommand(input)
 	}
diff --git a/cmd/micro/messenger.go b/cmd/micro/messenger.go
index b75a779f..50100c40 100644
--- a/cmd/micro/messenger.go
+++ b/cmd/micro/messenger.go
@@ -4,8 +4,10 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
+	"io/ioutil"
 	"os"
 	"strconv"
+	"strings"
 
 	"github.com/zyedidia/tcell"
 )
@@ -122,9 +124,16 @@ func (m *Messenger) YesNoPrompt(prompt string) (bool, bool) {
 	}
 }
 
+type Completion int
+
+const (
+	NoCompletion Completion = iota
+	FileCompletion
+)
+
 // Prompt sends the user a message and waits for a response to be typed in
 // This function blocks the main loop while waiting for input
-func (m *Messenger) Prompt(prompt, historyType string) (string, bool) {
+func (m *Messenger) Prompt(prompt, historyType string, completionType Completion) (string, bool) {
 	m.hasPrompt = true
 	m.Message(prompt)
 	if _, ok := m.history[historyType]; !ok {
@@ -153,6 +162,34 @@ func (m *Messenger) Prompt(prompt, historyType string) (string, bool) {
 				m.hasPrompt = false
 				response, canceled = m.response, false
 				m.history[historyType][len(m.history[historyType])-1] = response
+			case tcell.KeyTab:
+				if completionType == FileCompletion {
+					dirs := strings.Split(m.response, "/")
+					var files []os.FileInfo
+					var err error
+					if len(dirs) > 1 {
+						files, err = ioutil.ReadDir(strings.Join(dirs[:len(dirs)-1], "/"))
+					} else {
+						files, err = ioutil.ReadDir(".")
+					}
+					if err != nil {
+						continue
+					}
+					var suggestions []string
+					for _, f := range files {
+						name := f.Name()
+						if f.IsDir() {
+							name += "/"
+						}
+						if strings.HasPrefix(name, dirs[len(dirs)-1]) {
+							suggestions = append(suggestions, name)
+						}
+					}
+					if len(suggestions) == 1 {
+						m.response = strings.Join(dirs[:len(dirs)-1], "/") + "/" + suggestions[0]
+						m.cursorx = Count(m.response)
+					}
+				}
 			}
 		}
 
@@ -177,13 +214,13 @@ func (m *Messenger) HandleEvent(event tcell.Event, history []string) {
 			if m.historyNum > 0 {
 				m.historyNum--
 				m.response = history[m.historyNum]
-				m.cursorx = len(m.response)
+				m.cursorx = Count(m.response)
 			}
 		case tcell.KeyDown:
 			if m.historyNum < len(history)-1 {
 				m.historyNum++
 				m.response = history[m.historyNum]
-				m.cursorx = len(m.response)
+				m.cursorx = Count(m.response)
 			}
 		case tcell.KeyLeft:
 			if m.cursorx > 0 {
diff --git a/cmd/micro/view.go b/cmd/micro/view.go
index c12891ab..8e60c636 100644
--- a/cmd/micro/view.go
+++ b/cmd/micro/view.go
@@ -165,7 +165,7 @@ func (v *View) ScrollDown(n int) {
 // The message is what to print after saying "You have unsaved changes. "
 func (v *View) CanClose(msg string) bool {
 	if v.Buf.IsModified {
-		quit, canceled := messenger.Prompt("You have unsaved changes. "+msg, "Unsaved")
+		quit, canceled := messenger.Prompt("You have unsaved changes. "+msg, "Unsaved", NoCompletion)
 		if !canceled {
 			if strings.ToLower(quit) == "yes" || strings.ToLower(quit) == "y" {
 				return true