Add very basic track endpoint

api/api.go

@@ -125,3 +125,28 @@ func Unsubmit(url string) error {
 	}
 	return fmt.Errorf("failed to unsubmit - %s", pe.Error)
 }
+
+// Tracks gets the current list of active and inactive language tracks.
+func Tracks(url string) ([]*Track, error) {
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return []*Track{}, err
+	}
+	req.Header.Set("User-Agent", UserAgent)
+
+	res, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return []*Track{}, err
+	}
+	defer res.Body.Close()
+
+	var payload struct {
+		Tracks []*Track
+	}
+	dec := json.NewDecoder(res.Body)
+	err = dec.Decode(&payload)
+	if err != nil {
+		return []*Track{}, err
+	}
+	return payload.Tracks, nil
+}

api/track.go

@@ -0,0 +1,20 @@
+package api
+
+import "fmt"
+
+// Track is a collection of problems in a given language.
+type Track struct {
+	ID       string   `json:"id"`
+	Language string   `json:"language"`
+	Active   bool     `json:"active"`
+	Problems []string `json:"problems"`
+}
+
+// Len lists the number of problems a track has.
+func (t *Track) Len() int {
+	return len(t.Problems)
+}
+
+func (t *Track) String() string {
+	return fmt.Sprintf("%s (%s)", t.Language, t.ID)
+}

cmd/tracks.go

@@ -0,0 +1,37 @@
+package cmd
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/codegangsta/cli"
+	"github.com/exercism/cli/api"
+	"github.com/exercism/cli/config"
+	"github.com/exercism/cli/user"
+)
+
+// Tracks lists available tracks.
+func Tracks(ctx *cli.Context) {
+	c, err := config.Read(ctx.GlobalString("config"))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	tracks, err := api.Tracks(fmt.Sprintf("%s/tracks", c.XAPI))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	curr := user.NewCurriculum(tracks)
+	fmt.Println("\nActive language tracks:")
+	curr.Report(user.TrackActive)
+	fmt.Println("\nInactive language tracks:")
+	curr.Report(user.TrackInactive)
+
+	// TODO: implement `list` command to list problems in a track
+	msg := `
+Related commands:
+    exercism fetch (see 'exercism help fetch')
+	`
+	fmt.Println(msg)
+}

main.go

@@ -25,6 +25,7 @@ const (
 	descRestore   = "Restores completed and current problems on from exercism.io, along with your most recent iteration for each."
 	descSubmit    = "Submits a new iteration to a problem on exercism.io."
 	descUnsubmit  = "Deletes the most recently submitted iteration."
+	descTracks    = "List the available language tracks"
 	descLogin     = "DEPRECATED: Interactively saves exercism.io api credentials."
 	descLogout    = "DEPRECATED: Clear exercism.io api credentials"
 
@@ -112,6 +113,12 @@ func main() {
 			Usage:     descUnsubmit,
 			Action:    cmd.Unsubmit,
 		},
+		{
+			Name:      "tracks",
+			ShortName: "t",
+			Usage:     descTracks,
+			Action:    cmd.Tracks,
+		},
 	}
 	if err := app.Run(os.Args); err != nil {
 

user/curriculum.go

@@ -0,0 +1,77 @@
+package user
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/exercism/cli/api"
+)
+
+// Status is the status of a track (active/inactive).
+type Status bool
+
+const (
+	// TrackActive represents an active track.
+	// Problems from active tracks will be delivered with the `fetch` command.
+	TrackActive Status = true
+	// TrackInactive represents an inactive track.
+	// It is possible to fetch problems from an inactive track, and
+	// submit them to the website, but these will not automatically be
+	// delivered in the global `fetch` command.
+	TrackInactive Status = false
+)
+
+// Curriculum is a collection of language tracks.
+type Curriculum struct {
+	Tracks []*api.Track
+	wLang  int
+	wID    int
+}
+
+// NewCurriculum returns a collection of language tracks.
+func NewCurriculum(tracks []*api.Track) *Curriculum {
+	return &Curriculum{Tracks: tracks}
+}
+
+// Report creates a table of the tracks that have the requested status.
+func (cur *Curriculum) Report(status Status) {
+	for _, track := range cur.Tracks {
+		if Status(track.Active) == status {
+			fmt.Println(
+				"    ",
+				track.Language,
+				strings.Repeat(" ", cur.lenLang()-len(track.Language)+1),
+				track.ID,
+				strings.Repeat(" ", cur.lenID()-len(track.ID)+1),
+				track.Len(),
+				"problems",
+			)
+		}
+	}
+}
+
+func (cur *Curriculum) lenLang() int {
+	if cur.wLang > 0 {
+		return cur.wLang
+	}
+
+	for _, track := range cur.Tracks {
+		if len(track.Language) > cur.wLang {
+			cur.wLang = len(track.Language)
+		}
+	}
+	return cur.wLang
+}
+
+func (cur *Curriculum) lenID() int {
+	if cur.wID > 0 {
+		return cur.wID
+	}
+
+	for _, track := range cur.Tracks {
+		if len(track.ID) > cur.wID {
+			cur.wID = len(track.ID)
+		}
+	}
+	return cur.wID
+}