Prompt library updates (#11988)

Restructure prompts & the prompt library.

- Prompts are now written in markdown
- The prompt manager has a picker and editable prompts
- Saving isn't wired up yet
- This also removes the "Insert active prompt" button as this concept doesn't exist anymore, and will be replaced with slash commands.

I didn't staff flag this, but if you do play around with it expect it to still be pretty rough.

Release Notes:

- N/A

---------

Co-authored-by: Nathan Sobo <1789+nathansobo@users.noreply.github.com>
Co-authored-by: Antonio Scandurra <me@as-cii.com>

crates/assistant/src/prompts/prompt_library.rs

@@ -0,0 +1,152 @@
+use anyhow::Context;
+use collections::HashMap;
+use fs::Fs;
+
+use parking_lot::RwLock;
+use serde::{Deserialize, Serialize};
+use smol::stream::StreamExt;
+use std::sync::Arc;
+use util::paths::PROMPTS_DIR;
+use uuid::Uuid;
+
+use super::prompt::StaticPrompt;
+
+#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash, Serialize, Deserialize)]
+pub struct PromptId(pub Uuid);
+
+#[allow(unused)]
+impl PromptId {
+    pub fn new() -> Self {
+        Self(Uuid::new_v4())
+    }
+}
+
+#[derive(Default, Serialize, Deserialize)]
+pub struct PromptLibraryState {
+    /// A set of prompts that all assistant contexts will start with
+    default_prompt: Vec<PromptId>,
+    /// All [Prompt]s loaded into the library
+    prompts: HashMap<PromptId, StaticPrompt>,
+    /// Prompts that have been changed but haven't been
+    /// saved back to the file system
+    dirty_prompts: Vec<PromptId>,
+    version: usize,
+}
+
+pub struct PromptLibrary {
+    state: RwLock<PromptLibraryState>,
+}
+
+impl Default for PromptLibrary {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl PromptLibrary {
+    fn new() -> Self {
+        Self {
+            state: RwLock::new(PromptLibraryState::default()),
+        }
+    }
+
+    pub fn prompts(&self) -> Vec<(PromptId, StaticPrompt)> {
+        let state = self.state.read();
+        state
+            .prompts
+            .iter()
+            .map(|(id, prompt)| (*id, prompt.clone()))
+            .collect()
+    }
+
+    pub fn first_prompt_id(&self) -> Option<PromptId> {
+        let state = self.state.read();
+        state.prompts.keys().next().cloned()
+    }
+
+    pub fn prompt(&self, id: PromptId) -> Option<StaticPrompt> {
+        let state = self.state.read();
+        state.prompts.get(&id).cloned()
+    }
+
+    /// Save the current state of the prompt library to the
+    /// file system as a JSON file
+    pub async fn save(&self, fs: Arc<dyn Fs>) -> anyhow::Result<()> {
+        fs.create_dir(&PROMPTS_DIR).await?;
+
+        let path = PROMPTS_DIR.join("index.json");
+
+        let json = {
+            let state = self.state.read();
+            serde_json::to_string(&*state)?
+        };
+
+        fs.atomic_write(path, json).await?;
+
+        Ok(())
+    }
+
+    /// Load the state of the prompt library from the file system
+    /// or create a new one if it doesn't exist
+    pub async fn load(fs: Arc<dyn Fs>) -> anyhow::Result<Self> {
+        let path = PROMPTS_DIR.join("index.json");
+
+        let state = if fs.is_file(&path).await {
+            let json = fs.load(&path).await?;
+            serde_json::from_str(&json)?
+        } else {
+            PromptLibraryState::default()
+        };
+
+        let mut prompt_library = Self {
+            state: RwLock::new(state),
+        };
+
+        prompt_library.load_prompts(fs).await?;
+
+        Ok(prompt_library)
+    }
+
+    /// Load all prompts from the file system
+    /// adding them to the library if they don't already exist
+    pub async fn load_prompts(&mut self, fs: Arc<dyn Fs>) -> anyhow::Result<()> {
+        // let current_prompts = self.all_prompt_contents().clone();
+
+        // For now, we'll just clear the prompts and reload them all
+        self.state.get_mut().prompts.clear();
+
+        let mut prompt_paths = fs.read_dir(&PROMPTS_DIR).await?;
+
+        while let Some(prompt_path) = prompt_paths.next().await {
+            let prompt_path = prompt_path.with_context(|| "Failed to read prompt path")?;
+
+            if !fs.is_file(&prompt_path).await
+                || prompt_path.extension().and_then(|ext| ext.to_str()) != Some("md")
+            {
+                continue;
+            }
+
+            let json = fs
+                .load(&prompt_path)
+                .await
+                .with_context(|| format!("Failed to load prompt {:?}", prompt_path))?;
+            let mut static_prompt = StaticPrompt::new(json);
+
+            if let Some(file_name) = prompt_path.file_name() {
+                let file_name = file_name.to_string_lossy().into_owned();
+                static_prompt.file_name(file_name);
+            }
+
+            let state = self.state.get_mut();
+
+            let id = Uuid::new_v4();
+            state.prompts.insert(PromptId(id), static_prompt);
+            state.version += 1;
+        }
+
+        // Write any changes back to the file system
+        self.save(fs.clone()).await?;
+
+        Ok(())
+    }
+}