Global repo file as the default

This patch implments the new workflow mentioned in #31, in which
the program still tries to find a repo file in the working directory
first, and it tries the global one in the home directory if no one
is found.

In this patch, the condition check of the existence of the repo file
is done in `todolist/file_store.go` at the very early step before
the input routing.

3 files changed, 26 insertions, 5 deletions

diff --git a/todo.go b/todo.go
index 2a45f28..f7d994d 100644
--- a/todo.go
+++ b/todo.go
@@ -110,6 +110,10 @@ func usage() {
 
 func routeInput(command string, input string) {
 	app := todolist.NewApp()
+	if app == nil {
+		return
+	}
+
 	switch command {
 	case "l", "list", "agenda":
 		app.ListTodos(input)
diff --git a/todolist/app.go b/todolist/app.go
index 1ab6b20..e3d8cc7 100644
--- a/todolist/app.go
+++ b/todolist/app.go
@@ -15,6 +15,11 @@ type App struct {
 
 func NewApp() *App {
 	app := &App{TodoList: &TodoList{}, TodoStore: NewFileStore()}
+	if app.TodoStore.FileLocation == "" {
+		fmt.Println("No todo file found!")
+		fmt.Println("You may run 'todo init' to initialize an empty repo in current directory.")
+		return nil
+	}
 	return app
 }
 
diff --git a/todolist/file_store.go b/todolist/file_store.go
index 5413295..63738b2 100644
--- a/todolist/file_store.go
+++ b/todolist/file_store.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"os/user"
 )
 
 type FileStore struct {
@@ -13,22 +14,33 @@ type FileStore struct {
 }
 
 func NewFileStore() *FileStore {
-	return &FileStore{FileLocation: ".todos.json", Loaded: false}
+	localrepo := ".todos.json"
+	usr, _ := user.Current()
+	homerepo := fmt.Sprintf("%s/.todos.json", usr.HomeDir)
+	_, err1 := os.Stat(localrepo)
+	_, err2 := os.Stat(homerepo)
+
+	if err1 == nil {
+		return &FileStore{FileLocation: localrepo, Loaded: false}
+	} else if err2 == nil {
+		return &FileStore{FileLocation: homerepo, Loaded: false}
+	} else {
+		return &FileStore{FileLocation: "", Loaded: false}
+	}
 }
 
 func (f *FileStore) Load() ([]*Todo, error) {
 	data, err := ioutil.ReadFile(f.FileLocation)
 	if err != nil {
-		fmt.Println("No todo file found!")
-		fmt.Println("Initialize a new todo repo by running 'todo init'")
+		fmt.Println("Error reading", f.FileLocation, "by", err)
 		return nil, err
-		os.Exit(0)
+		os.Exit(1)
 	}
 
 	var todos []*Todo
 	jerr := json.Unmarshal(data, &todos)
 	if jerr != nil {
-		fmt.Println("Error reading json data", jerr)
+		fmt.Println("Error reading", f.FileLocation, "by", jerr)
 		return nil, jerr
 		os.Exit(1)
 	}