Improve demo command output

Author: kytrinyx

api/problem.go

@@ -18,7 +18,7 @@ type Problem struct {
 }
 
 func (p *Problem) String() string {
-	return fmt.Sprintf("%s - %s in %s", p.ID, p.Name, p.Language)
+	return fmt.Sprintf("%s (%s)", p.Name, p.Language)
 }
 
 func (p *Problem) ExistsIn(dir string) bool {

handlers/demo.go

@@ -28,6 +28,10 @@ func Demo(ctx *cli.Context) {
 			fmt.Println(err)
 			return
 		}
-		fmt.Printf("%s (%s) - %s/%s\n", problem.Name, problem.Language, c.Dir, problem.ID)
 	}
+
+	NewHomework(problems, c).Report()
+
+	fmt.Println()
+	fmt.Println("Next step: choose a language, read the README, and make the test suite pass.")
 }

handlers/homework.go

@@ -0,0 +1,48 @@
+package handlers
+
+import (
+	"fmt"
+
+	"github.com/exercism/cli/api"
+	"github.com/exercism/cli/config"
+)
+
+type Item struct {
+	Title string
+	Path  string
+}
+
+type Homework struct {
+	Items    []*Item
+	template string
+}
+
+func (hw Homework) MaxTitleWidth() int {
+	var max int
+	for _, item := range hw.Items {
+		if len(item.Title) > max {
+			max = len(item.Title)
+		}
+	}
+	return max
+}
+
+func NewHomework(problems []*api.Problem, c *config.Config) Homework {
+	hw := Homework{}
+	for _, problem := range problems {
+		item := &Item{
+			Title: problem.String(),
+			Path:  fmt.Sprintf("%s/%s", c.Dir, problem.ID),
+		}
+		hw.Items = append(hw.Items, item)
+	}
+
+	hw.template = fmt.Sprintf("%%%ds %%s\n", hw.MaxTitleWidth())
+	return hw
+}
+
+func (hw Homework) Report() {
+	for _, item := range hw.Items {
+		fmt.Printf(hw.template, item.Title, item.Path)
+	}
+}