update chat ui

crates/state/src/file.rs

@@ -9,16 +9,15 @@ use base64::engine::general_purpose::{STANDARD, STANDARD_NO_PAD, URL_SAFE, URL_S
 use futures::AsyncReadExt;
 use gpui::http_client::AsyncBody;
 use gpui::{AsyncApp, SharedString};
-use nostr::nips::nip94::Sha256Hash;
-use nostr_sdk::prelude::*;
-use sha2::{Digest, Sha256};
-
 #[cfg(not(target_arch = "wasm32"))]
 use gpui_tokio::Tokio;
 #[cfg(not(target_arch = "wasm32"))]
 use mime_guess::from_path;
+use nostr::nips::nip94::Sha256Hash;
 #[cfg(not(target_arch = "wasm32"))]
 use nostr_blossom::prelude::*;
+use nostr_sdk::prelude::*;
+use sha2::{Digest, Sha256};
 
 pub const ALGORITHM: &str = "aes-gcm";
 
@@ -243,6 +242,63 @@ pub async fn download_and_decrypt(
     decrypt(&data, key, nonce)
 }
 
+/// Download and decrypt a file attachment into a temporary file.
+///
+/// The same attachment always maps to the same path, so callers can render the
+/// result directly (e.g. with `img`) without downloading it more than once.
+#[cfg(not(target_arch = "wasm32"))]
+pub async fn download_and_decrypt_to_file(
+    file: &FileAttachment,
+    cx: &AsyncApp,
+) -> Result<PathBuf, Error> {
+    let name = file
+        .sha256
+        .clone()
+        .unwrap_or_else(|| sha256_hex(file.url.as_str().as_bytes()));
+
+    let extension = mime_guess::get_mime_extensions_str(&file.mime)
+        .and_then(|extensions| extensions.first())
+        .copied()
+        .unwrap_or("bin");
+
+    let path = std::env::temp_dir()
+        .join("coop-files")
+        .join(format!("{name}.{extension}"));
+
+    if smol::fs::metadata(&path).await.is_ok() {
+        return Ok(path);
+    }
+
+    let data = download_and_decrypt(
+        &file.url,
+        &file.key,
+        &file.nonce,
+        file.sha256.as_deref(),
+        cx,
+    )
+    .await?;
+
+    let Some(parent) = path.parent() else {
+        bail!("Invalid file path");
+    };
+    smol::fs::create_dir_all(parent).await?;
+
+    // Write under a temporary name first, so an interrupted download is never reused
+    let partial = path.with_extension("download");
+    smol::fs::write(&partial, data).await?;
+    smol::fs::rename(&partial, &path).await?;
+
+    Ok(path)
+}
+
+#[cfg(target_arch = "wasm32")]
+pub async fn download_and_decrypt_to_file(
+    _file: &FileAttachment,
+    _cx: &AsyncApp,
+) -> Result<PathBuf, Error> {
+    Err(anyhow!("File download not supported on web"))
+}
+
 fn tag_value<'a>(tags: &'a Tags, name: &str) -> Option<&'a str> {
     tags.iter()
         .find(|tag| tag.kind() == name)