Do unmarshaling in thing struct

Signed-off-by: Vartan Benohanian <vartanbeno@gmail.com>

reddit/message.go

@@ -35,14 +35,17 @@ type Message struct {
 	IsComment bool `json:"was_comment"`
 }
 
+type inboxThing struct {
+	Kind string   `json:"kind"`
+	Data *Message `json:"data"`
+}
+
 type inboxListing struct {
 	inboxThings
 	after  string
 	before string
 }
 
-var _ anchor = &inboxListing{}
-
 func (l *inboxListing) After() string {
 	return l.after
 }
@@ -73,14 +76,12 @@ func (l *inboxListing) UnmarshalJSON(b []byte) error {
 	return nil
 }
 
-// The returned JSON for comments is a bit different.
-// It looks for like the Message struct.
 type inboxThings struct {
 	Comments []*Message
 	Messages []*Message
 }
 
-// init initializes or clears the inbox.
+// init initializes or clears the listing.
 func (t *inboxThings) init() {
 	t.Comments = make([]*Message, 0)
 	t.Messages = make([]*Message, 0)
@@ -90,27 +91,24 @@ func (t *inboxThings) init() {
 func (t *inboxThings) UnmarshalJSON(b []byte) error {
 	t.init()
 
-	var things []thing
+	var things []inboxThing
 	if err := json.Unmarshal(b, &things); err != nil {
 		return err
 	}
 
+	t.add(things...)
+	return nil
+}
+
+func (t *inboxThings) add(things ...inboxThing) {
 	for _, thing := range things {
 		switch thing.Kind {
 		case kindComment:
-			v := new(Message)
-			if err := json.Unmarshal(thing.Data, v); err == nil {
-				t.Comments = append(t.Comments, v)
-			}
+			t.Comments = append(t.Comments, thing.Data)
 		case kindMessage:
-			v := new(Message)
-			if err := json.Unmarshal(thing.Data, v); err == nil {
-				t.Messages = append(t.Messages, v)
-			}
+			t.Messages = append(t.Messages, thing.Data)
 		}
 	}
-
-	return nil
 }
 
 // SendMessageRequest represents a request to send a message.

reddit/subreddit.go

@@ -17,11 +17,6 @@ type SubredditService struct {
 	client *Client
 }
 
-type rootSubreddit struct {
-	Kind string     `json:"kind,omitempty"`
-	Data *Subreddit `json:"data,omitempty"`
-}
-
 type rootSubredditNames struct {
 	Names []string `json:"names,omitempty"`
 }
@@ -133,13 +128,13 @@ func (s *SubredditService) Get(ctx context.Context, name string) (*Subreddit, *R
 		return nil, nil, err
 	}
 
-	root := new(rootSubreddit)
+	root := new(thing)
 	resp, err := s.client.Do(ctx, req, root)
 	if err != nil {
 		return nil, resp, err
 	}
 
-	return root.Data, resp, nil
+	return root.Subreddit(), resp, nil
 }
 
 // Popular returns popular subreddits.

reddit/things.go

@@ -2,6 +2,7 @@ package reddit
 
 import (
 	"encoding/json"
+	"fmt"
 )
 
 const (
@@ -23,8 +24,79 @@ const (
 // Its kind reprsents what it is and what is stored in the Data field.
 // e.g. t1 = comment, t2 = user, t3 = post, etc.
 type thing struct {
-	Kind string          `json:"kind"`
-	Data json.RawMessage `json:"data"`
+	Kind string      `json:"kind"`
+	Data interface{} `json:"data"`
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface.
+func (t *thing) UnmarshalJSON(b []byte) error {
+	root := new(struct {
+		Kind string          `json:"kind"`
+		Data json.RawMessage `json:"data"`
+	})
+
+	err := json.Unmarshal(b, root)
+	if err != nil {
+		return err
+	}
+
+	t.Kind = root.Kind
+	var v interface{}
+
+	switch t.Kind {
+	case kindComment:
+		v = new(Comment)
+	case kindMore:
+		v = new(More)
+	case kindAccount:
+		v = new(User)
+	case kindPost:
+		v = new(Post)
+	case kindSubreddit:
+		v = new(Subreddit)
+	case kindModAction:
+		v = new(ModAction)
+	default:
+		return fmt.Errorf("unrecognized kind: %q", t.Kind)
+	}
+
+	err = json.Unmarshal(root.Data, v)
+	if err != nil {
+		return err
+	}
+
+	t.Data = v
+	return nil
+}
+
+func (t *thing) Comment() *Comment {
+	v, _ := t.Data.(*Comment)
+	return v
+}
+
+func (t *thing) More() *More {
+	v, _ := t.Data.(*More)
+	return v
+}
+
+func (t *thing) User() *User {
+	v, _ := t.Data.(*User)
+	return v
+}
+
+func (t *thing) Post() *Post {
+	v, _ := t.Data.(*Post)
+	return v
+}
+
+func (t *thing) Subreddit() *Subreddit {
+	v, _ := t.Data.(*Subreddit)
+	return v
+}
+
+func (t *thing) ModAction() *ModAction {
+	v, _ := t.Data.(*ModAction)
+	return v
 }
 
 type anchor interface {
@@ -32,7 +104,7 @@ type anchor interface {
 	Before() string
 }
 
-// listing holds things coming from the Reddit API.
+// listing is a list of things coming from the Reddit API.
 // It also contains the after/before anchors useful for subsequent requests.
 type listing struct {
 	things
@@ -40,8 +112,6 @@ type listing struct {
 	before string
 }
 
-var _ anchor = &listing{}
-
 func (l *listing) After() string {
 	return l.after
 }
@@ -100,42 +170,27 @@ func (t *things) UnmarshalJSON(b []byte) error {
 		return err
 	}
 
+	t.add(things...)
+	return nil
+}
+
+func (t *things) add(things ...thing) {
 	for _, thing := range things {
-		switch thing.Kind {
-		case kindComment:
-			v := new(Comment)
-			if err := json.Unmarshal(thing.Data, v); err == nil {
-				t.Comments = append(t.Comments, v)
-			}
-		case kindMore:
-			v := new(More)
-			if err := json.Unmarshal(thing.Data, v); err == nil {
-				t.Mores = append(t.Mores, v)
-			}
-		case kindAccount:
-			v := new(User)
-			if err := json.Unmarshal(thing.Data, v); err == nil {
-				t.Users = append(t.Users, v)
-			}
-		case kindPost:
-			v := new(Post)
-			if err := json.Unmarshal(thing.Data, v); err == nil {
-				t.Posts = append(t.Posts, v)
-			}
-		case kindSubreddit:
-			v := new(Subreddit)
-			if err := json.Unmarshal(thing.Data, v); err == nil {
-				t.Subreddits = append(t.Subreddits, v)
-			}
-		case kindModAction:
-			v := new(ModAction)
-			if err := json.Unmarshal(thing.Data, v); err == nil {
-				t.ModActions = append(t.ModActions, v)
-			}
+		switch v := thing.Data.(type) {
+		case *Comment:
+			t.Comments = append(t.Comments, v)
+		case *More:
+			t.Mores = append(t.Mores, v)
+		case *User:
+			t.Users = append(t.Users, v)
+		case *Post:
+			t.Posts = append(t.Posts, v)
+		case *Subreddit:
+			t.Subreddits = append(t.Subreddits, v)
+		case *ModAction:
+			t.ModActions = append(t.ModActions, v)
 		}
 	}
-
-	return nil
 }
 
 // Comment is a comment posted by a user.

reddit/user.go

@@ -15,11 +15,6 @@ type UserService struct {
 	client *Client
 }
 
-type rootUser struct {
-	Kind string `json:"kind,omitempty"`
-	Data *User  `json:"data,omitempty"`
-}
-
 // User represents a Reddit user.
 type User struct {
 	// this is not the full ID, watch out.
@@ -83,13 +78,13 @@ func (s *UserService) Get(ctx context.Context, username string) (*User, *Respons
 		return nil, nil, err
 	}
 
-	root := new(rootUser)
+	root := new(thing)
 	resp, err := s.client.Do(ctx, req, root)
 	if err != nil {
 		return nil, resp, err
 	}
 
-	return root.Data, resp, nil
+	return root.User(), resp, nil
 }
 
 // GetMultipleByID returns multiple users from their full IDs.