From 243a64b7b9eef4d53812cc8eda3744ab63f55c3f Mon Sep 17 00:00:00 2001
From: Peter Cai <peter@typeblog.net>
Date: Tue, 7 Apr 2020 20:54:04 +0800
Subject: [PATCH] implement basic KV binding

---
 Cargo.toml   |  1 +
 src/blog.rs  | 45 +++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs   |  2 ++
 src/sn.rs    | 13 +++++++++++--
 src/store.rs | 39 +++++++++++++++++++++++++++++++++++++++
 5 files changed, 98 insertions(+), 2 deletions(-)
 create mode 100644 src/blog.rs
 create mode 100644 src/store.rs

diff --git a/Cargo.toml b/Cargo.toml
index b64758b..aa7330d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,6 +13,7 @@ default = ["console_error_panic_hook", "wee_alloc"]
 [dependencies]
 cfg-if = "0.1.2"
 lazy_static = "1.4"
+js-sys = "0.3"
 serde = { version = "1.0", features = [ "derive" ] }
 serde_json = "1.0"
 wasm-bindgen = "0.2"
diff --git a/src/blog.rs b/src/blog.rs
new file mode 100644
index 0000000..9b846f3
--- /dev/null
+++ b/src/blog.rs
@@ -0,0 +1,45 @@
+// Utility functions and structs for the blogging system 
+// Due to limitations of the Cloudflare Workers KV, we do not
+// store the entire state in one record; instead, different
+// parts are stroed in different records. This also increases
+// efficiency, since the program won't need to load anything
+// unnecessary from KV.
+use crate::store;
+use crate::utils::*;
+use serde::{Serialize, Deserialize};
+use std::vec::Vec;
+
+// A list of the UUIDs of all published blog posts
+// This should be SORTED with the newest posts at lower indices (closer to 0)
+// The user may edit this via KV UI to change ordering and such
+// by default new posts are always added to the top
+#[derive(Serialize, Deserialize)]
+pub struct PostsList(pub Vec<String>);
+
+impl PostsList {
+    pub async fn load() -> PostsList {
+        match store::get_obj("posts_list").await {
+            Ok(v) => PostsList(v),
+            // Don't panic on empty
+            // TODO: What if the user messed up when editing?
+            //       That would cause a decode failure and all data will be gone
+            //       if a new post is added or updated (overwriting the KV value) 
+            //       under this logic
+            //       (if no new post is added then nothing bad would happen;
+            //        the user would probably notice when trying to visit the blog home page)
+            Err(_) => PostsList(vec![])
+        }
+    }
+
+    pub fn has_post(&self, uuid: &str) -> bool {
+        self.0.contains(&uuid.into())
+    }
+
+    // Add a post to the list and then update the record in KV
+    // Also consumes self, as this should normally be the last action
+    // in an API call
+    pub async fn add_post(mut self, uuid: &str) -> MyResult<()> {
+        self.0.insert(0, uuid.into());
+        store::put_obj_pretty("posts_list", self.0).await
+    }
+}
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
index f2e36ef..999e4c9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -4,6 +4,8 @@ extern crate lazy_static;
 #[macro_use]
 mod utils;
 mod router;
+mod store;
+mod blog;
 mod sn;
 
 use cfg_if::cfg_if;
diff --git a/src/sn.rs b/src/sn.rs
index 1024c1e..f97e806 100644
--- a/src/sn.rs
+++ b/src/sn.rs
@@ -1,5 +1,5 @@
 // Interface for Standard Notes (Actions)
-use crate::CONFIG;
+use crate::{CONFIG, blog};
 use crate::router::Router;
 use crate::utils::*;
 use serde::{Serialize, Serializer};
@@ -28,8 +28,17 @@ async fn get_actions(_req: Request, url: Url) -> MyResult<Response> {
     let origin = url.origin();
     let mut actions = vec![];
 
+    // Show different options depending on whether the post already exists
+    let post_exists = match params.get("item_uuid") {
+        Some(uuid) => {
+            let posts = blog::PostsList::load().await;
+            posts.has_post(&uuid)
+        },
+        None => false
+    };
+
     actions.push(Action {
-        label: "Publish".into(),
+        label: if post_exists { "Update".into() } else { "Publish".into() },
         url: format!("{}/post?secret={}", origin, CONFIG.secret.clone()),
         verb: Verb::Post,
         context: Context::Item,
diff --git a/src/store.rs b/src/store.rs
new file mode 100644
index 0000000..ba521ec
--- /dev/null
+++ b/src/store.rs
@@ -0,0 +1,39 @@
+// Bindings to Cloudflare Workers KV
+use crate::utils::*;
+use js_sys::Promise;
+use serde::Serialize;
+use serde::de::DeserializeOwned;
+use wasm_bindgen::prelude::*;
+use wasm_bindgen_futures::JsFuture;
+
+#[wasm_bindgen]
+extern "C" {
+    #[wasm_bindgen(js_namespace = PAPRIKA, js_name = "get")]
+    fn kv_get(key: &str) -> Promise;
+    #[wasm_bindgen(js_namespace = PAPRIKA, js_name = "put")]
+    fn kv_put_str(key: &str, value: &str) -> Promise;
+}
+
+pub async fn get_str(key: &str) -> MyResult<String> {
+    Ok(JsFuture::from(kv_get(key)).await.internal_err()?.as_string().unwrap())
+}
+
+pub async fn get_obj<T: DeserializeOwned>(key: &str) -> MyResult<T> {
+    let res = get_str(key).await?;
+    Ok(serde_json::from_str(&res).internal_err()?)
+}
+
+pub async fn put_str(key: &str, value: &str) -> MyResult<()> {
+    JsFuture::from(kv_put_str(key, value)).await.internal_err()?;
+    Ok(())
+}
+
+pub async fn put_obj<T: Serialize>(key: &str, value: T) -> MyResult<()> {
+    put_str(key, &serde_json::to_string(&value).internal_err()?).await
+}
+
+// Some objects may be available for manual editing; thus making it pretty may be helpful
+// For example, the user may want to manually edit the order in which posts appear
+pub async fn put_obj_pretty<T: Serialize>(key: &str, value: T) -> MyResult<()> {
+    put_str(key, &serde_json::to_string_pretty(&value).internal_err()?).await
+}
\ No newline at end of file