From e6d9bfab2c41bbb53b9ec3836aed72184c75f94c Mon Sep 17 00:00:00 2001
From: Kevin Schoon <kevinschoon@gmail.com>
Date: Sun, 21 Jan 2018 01:20:01 +0800
Subject: [PATCH] add filtering

---
 main.go  | 13 ++++++++++++-
 types.go |  7 +++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/main.go b/main.go
index 39a7a3d..22e0d0c 100644
--- a/main.go
+++ b/main.go
@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"github.com/jawher/mow.cli"
 	"os"
+	"sort"
 	"time"
 )
 
@@ -48,13 +49,23 @@ func initialize(path *string) func(*cli.Cmd) {
 func list(path *string) func(*cli.Cmd) {
 	return func(cmd *cli.Cmd) {
 		cmd.Spec = "[OPTIONS]"
-		var asJSON = cmd.BoolOpt("json", false, "output task history as JSON")
+		var (
+			asJSON  = cmd.BoolOpt("json", false, "output task history as JSON")
+			reverse = cmd.BoolOpt("r reverse", false, "sort tasks assending in age")
+			limit   = cmd.IntOpt("n limit", 0, "limit the number of results by n")
+		)
 		cmd.Action = func() {
 			db, err := NewStore(*path)
 			maybe(err)
 			defer db.Close()
 			tasks, err := db.ReadTasks()
 			maybe(err)
+			if *reverse {
+				sort.Sort(sort.Reverse(ByID(tasks)))
+			}
+			if *limit > 0 && (len(tasks) > *limit) {
+				tasks = tasks[0:*limit]
+			}
 			if *asJSON {
 				maybe(json.NewEncoder(os.Stdout).Encode(tasks))
 				return
diff --git a/types.go b/types.go
index e879c94..64f5a29 100644
--- a/types.go
+++ b/types.go
@@ -75,6 +75,13 @@ type Task struct {
 	duration  time.Duration
 }
 
+// ByID is a sortable array of tasks
+type ByID []*Task
+
+func (b ByID) Len() int           { return len(b) }
+func (b ByID) Swap(i, j int)      { b[i], b[j] = b[j], b[i] }
+func (b ByID) Less(i, j int) bool { return b[i].ID < b[j].ID }
+
 // Pomodoro is a unit of time to spend working
 // on a single task.
 type Pomodoro struct {