1 files changed, 62 insertions, 4 deletions

diff --git a/gocomplete/pkgs.go b/gocomplete/pkgs.go
index d1f0331..8110ff9 100644
--- a/gocomplete/pkgs.go
+++ b/gocomplete/pkgs.go
@@ -3,7 +3,9 @@ package main
 import (
 	"go/build"
 	"io/ioutil"
+	"os"
 	"path/filepath"
+	"strings"
 
 	"github.com/posener/complete"
 )
@@ -11,11 +13,29 @@ import (
 // predictPackages completes packages in the directory pointed by a.Last
 // and packages that are one level below that package.
 func predictPackages(a complete.Args) (prediction []string) {
-	prediction = complete.PredictFilesSet(listPackages(a.Directory())).Predict(a)
-	if len(prediction) != 1 {
-		return
+	prediction = []string{a.Last}
+	lastPrediction := ""
+	for len(prediction) == 1 && (lastPrediction == "" || lastPrediction != prediction[0]) {
+		// if only one prediction, predict files within this prediction,
+		// for example, if the user entered 'pk' and we have a package named 'pkg',
+		// which is the only package prefixed with 'pk', we will automatically go one
+		// level deeper and give the user the 'pkg' and all the nested packages within
+		// that package.
+		lastPrediction = prediction[0]
+		a.Last = prediction[0]
+		prediction = predictLocalAndSystem(a)
 	}
-	return complete.PredictFilesSet(listPackages(prediction[0])).Predict(a)
+	return
+}
+
+func predictLocalAndSystem(a complete.Args) []string {
+	localDirs := complete.PredictFilesSet(listPackages(a.Directory())).Predict(a)
+	// System directories are not actual file names, for example: 'github.com/posener/complete' could
+	// be the argument, but the actual filename is in $GOPATH/src/github.com/posener/complete'. this
+	// is the reason to use the PredictSet and not the PredictDirs in this case.
+	s := systemDirs(a.Last)
+	sysDirs := complete.PredictSet(s...).Predict(a)
+	return append(localDirs, sysDirs...)
 }
 
 // listPackages looks in current pointed dir and in all it's direct sub-packages
@@ -48,3 +68,41 @@ func listPackages(dir string) (directories []string) {
 	}
 	return
 }
+
+func systemDirs(dir string) (directories []string) {
+	// get all paths from GOPATH environment variable and use their src directory
+	paths := strings.Split(os.Getenv("GOPATH"), ":")
+	for i := range paths {
+		paths[i] = filepath.Join(paths[i], "src")
+	}
+
+	// normalize the directory to be an actual directory since it could be with an additional
+	// characters after the last '/'.
+	if !strings.HasSuffix(dir, "/") {
+		dir = filepath.Dir(dir)
+	}
+
+	for _, basePath := range paths {
+		path := filepath.Join(basePath, dir)
+		files, err := ioutil.ReadDir(path)
+		if err != nil {
+			// path does not exists
+			continue
+		}
+		// add the base path as one of the completion options
+		switch dir {
+		case "", ".", "/", "./":
+		default:
+			directories = append(directories, dir)
+		}
+		// add all nested directories of the base path
+		// go supports only packages and not go files within the GOPATH
+		for _, f := range files {
+			if !f.IsDir() {
+				continue
+			}
+			directories = append(directories, filepath.Join(dir, f.Name())+"/")
+		}
+	}
+	return
+}