Add `CompletedDate` to todo item.

`CompletedDate` will save a timestamp in ISO8601 format (Internet date/
time format to preserve timezone information)

Added a new `Complete` and `Uncomplete` method for todo_item.
Currently a todo has a boolean flag and the timestamp to indicate that
the item is completed. The boolean flag could be kept for backward
compatibility (reading the json into memory), but should be omitted for
files being written.

1 files changed, 22 insertions, 8 deletions

diff --git a/todolist/todo_item.go b/todolist/todo_item.go
index 273df8d..c208f9f 100644
--- a/todolist/todo_item.go
+++ b/todolist/todo_item.go
@@ -2,15 +2,19 @@ package todolist
 
 import "time"
 
+// Timestamp format to include date, time with timezone support. Easy to parse
+const ISO8601_TIMESTAMP_FORMAT = "2006-01-02T15:04:05Z07:00"
+
 type Todo struct {
-	Id         int      `json:"id"`
-	Subject    string   `json:"subject"`
-	Projects   []string `json:"projects"`
-	Contexts   []string `json:"contexts"`
-	Due        string   `json:"due"`
-	Completed  bool     `json:"completed"`
-	Archived   bool     `json:"archived"`
-	IsPriority bool     `json:"isPriority"`
+	Id            int      `json:"id"`
+	Subject       string   `json:"subject"`
+	Projects      []string `json:"projects"`
+	Contexts      []string `json:"contexts"`
+	Due           string   `json:"due"`
+	Completed     bool     `json:"completed"`
+	CompletedDate string   `json:"completedDate"`
+	Archived      bool     `json:"archived"`
+	IsPriority    bool     `json:"isPriority"`
 }
 
 func NewTodo() *Todo {
@@ -30,3 +34,13 @@ func (t Todo) CalculateDueTime() time.Time {
 		return parsedTime
 	}
 }
+
+func (t *Todo) Complete() {
+	t.Completed = true
+	t.CompletedDate = bod(time.Now()).Format(ISO8601_TIMESTAMP_FORMAT)
+}
+
+func (t *Todo) Uncomplete() {
+	t.Completed = false
+	t.CompletedDate = ""
+}
\ No newline at end of file