From d3ace8c73bc1c6352bbaf18e0be66181643aa35e Mon Sep 17 00:00:00 2001
From: Matt Baer <matt@write.as>
Date: Fri, 21 Sep 2018 00:57:12 +0200
Subject: [PATCH] Support pinning posts

---
 post.go      | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 post_test.go | 14 ++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/post.go b/post.go
index 300c57e..225bda7 100644
--- a/post.go
+++ b/post.go
@@ -55,6 +55,20 @@ type (
 		Collection string `json:"-"`
 	}
 
+	// PinnedPostParams holds values for pinning a post
+	PinnedPostParams struct {
+		ID       string `json:"id"`
+		Position int    `json:"position"`
+	}
+
+	// BatchPostResult contains the post-specific result as part of a larger
+	// batch operation.
+	BatchPostResult struct {
+		ID           string `json:"id,omitempty"`
+		Code         int    `json:"code,omitempty"`
+		ErrorMessage string `json:"error_msg,omitempty"`
+	}
+
 	// ClaimPostResult contains the post-specific result for a request to
 	// associate a post to an account.
 	ClaimPostResult struct {
@@ -215,3 +229,38 @@ func (c *Client) GetUserPosts() (*[]Post, error) {
 	}
 	return p, nil
 }
+
+// PinPost pins a post in the given collection.
+// See https://developers.write.as/docs/api/#pin-a-post-to-a-collection
+func (c *Client) PinPost(alias string, pp *PinnedPostParams) error {
+	res := &[]BatchPostResult{}
+	env, err := c.post(fmt.Sprintf("/collections/%s/pin", alias), []*PinnedPostParams{pp}, res)
+	if err != nil {
+		return err
+	}
+
+	var ok bool
+	if res, ok = env.Data.(*[]BatchPostResult); !ok {
+		return fmt.Errorf("Wrong data returned from API.")
+	}
+
+	// Check for basic request errors on top level response
+	status := env.Code
+	if status != http.StatusOK {
+		if c.isNotLoggedIn(status) {
+			return fmt.Errorf("Not authenticated.")
+		}
+		return fmt.Errorf("Problem pinning post: %d. %v\n", status, err)
+	}
+
+	// Check the individual post result
+	if len(*res) == 0 || len(*res) > 1 {
+		return fmt.Errorf("Wrong data returned from API.")
+	}
+	if (*res)[0].Code != http.StatusOK {
+		return fmt.Errorf("Problem pinning post: %d", (*res)[0].Code)
+		// TODO: return ErrorMessage (right now it'll be empty)
+		// return fmt.Errorf("Problem pinning post: %v", res[0].ErrorMessage)
+	}
+	return nil
+}
diff --git a/post_test.go b/post_test.go
index 830a506..11562d6 100644
--- a/post_test.go
+++ b/post_test.go
@@ -73,6 +73,20 @@ func TestGetPost(t *testing.T) {
 	}
 }
 
+func TestPinPost(t *testing.T) {
+	dwac := NewDevClient()
+	_, err := dwac.LogIn("demo", "demo")
+	if err != nil {
+		t.Fatalf("Unable to log in: %v", err)
+	}
+	defer dwac.LogOut()
+
+	err = dwac.PinPost("tester", &PinnedPostParams{ID: "olx6uk7064heqltf"})
+	if err != nil {
+		t.Fatalf("Pin failed: %v", err)
+	}
+}
+
 func ExampleClient_CreatePost() {
 	c := NewClient()