agent: Add websearch tool (#28621)

Staff only for now. We'll work on making this usable for non zed.dev
users later

Release Notes:

- N/A

---------

Co-authored-by: Antonio Scandurra <me@as-cii.com>
Co-authored-by: Danilo Leal <daniloleal09@gmail.com>
Co-authored-by: Marshall Bowers <git@maxdeviant.com>

crates/web_search/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "web_search"
+version = "0.1.0"
+edition.workspace = true
+publish.workspace = true
+license = "GPL-3.0-or-later"
+
+[lints]
+workspace = true
+
+[lib]
+path = "src/web_search.rs"
+
+[dependencies]
+anyhow.workspace = true
+collections.workspace = true
+gpui.workspace = true
+serde.workspace = true
+workspace-hack.workspace = true
+zed_llm_client.workspace = true

crates/web_search/LICENSE-GPL

@@ -0,0 +1 @@
+../../LICENSE-GPL

crates/web_search/src/web_search.rs

@@ -0,0 +1,64 @@
+use anyhow::Result;
+use collections::HashMap;
+use gpui::{App, AppContext as _, Context, Entity, Global, SharedString, Task};
+use std::sync::Arc;
+use zed_llm_client::WebSearchResponse;
+
+pub fn init(cx: &mut App) {
+    let registry = cx.new(|_cx| WebSearchRegistry::default());
+    cx.set_global(GlobalWebSearchRegistry(registry));
+}
+
+#[derive(Clone, Eq, PartialEq, Hash, Debug, Ord, PartialOrd)]
+pub struct WebSearchProviderId(pub SharedString);
+
+pub trait WebSearchProvider {
+    fn id(&self) -> WebSearchProviderId;
+    fn search(&self, query: String, cx: &mut App) -> Task<Result<WebSearchResponse>>;
+}
+
+struct GlobalWebSearchRegistry(Entity<WebSearchRegistry>);
+
+impl Global for GlobalWebSearchRegistry {}
+
+#[derive(Default)]
+pub struct WebSearchRegistry {
+    providers: HashMap<WebSearchProviderId, Arc<dyn WebSearchProvider>>,
+    active_provider: Option<Arc<dyn WebSearchProvider>>,
+}
+
+impl WebSearchRegistry {
+    pub fn global(cx: &App) -> Entity<Self> {
+        cx.global::<GlobalWebSearchRegistry>().0.clone()
+    }
+
+    pub fn read_global(cx: &App) -> &Self {
+        cx.global::<GlobalWebSearchRegistry>().0.read(cx)
+    }
+
+    pub fn providers(&self) -> impl Iterator<Item = &Arc<dyn WebSearchProvider>> {
+        self.providers.values()
+    }
+
+    pub fn active_provider(&self) -> Option<Arc<dyn WebSearchProvider>> {
+        self.active_provider.clone()
+    }
+
+    pub fn set_active_provider(&mut self, provider: Arc<dyn WebSearchProvider>) {
+        self.active_provider = Some(provider.clone());
+        self.providers.insert(provider.id(), provider);
+    }
+
+    pub fn register_provider<T: WebSearchProvider + 'static>(
+        &mut self,
+        provider: T,
+        _cx: &mut Context<Self>,
+    ) {
+        let id = provider.id();
+        let provider = Arc::new(provider);
+        self.providers.insert(id.clone(), provider.clone());
+        if self.active_provider.is_none() {
+            self.active_provider = Some(provider);
+        }
+    }
+}