fix: validate downloaded model files

src/cli/commands.rs

@@ -8,6 +8,7 @@ use crate::config::{Config, Mode};
 use crate::core::{Database, EmbeddingEngine, Indexer, SearchEngine, ServerIndexer};
 use crate::server::{self, Client};
 use crate::ui::{self, SearchTui};
+use crate::utils::validation;
 use crate::watcher::FileWatcher;
 
 #[derive(Parser)]
@@ -867,9 +868,21 @@ fn run_models(action: ModelsAction, config: &mut Config) -> Result<()> {
                     .get("Qwen3-Embedding-0.6B-Q8_0.gguf")?;
 
                 pb.finish_and_clear();
-                ui::print_success(&format!("Downloaded: {}", embedding_path.display()));
-
-                config.set_embedding_model(embedding_path.to_string_lossy().to_string())?;
+
+                // Validate the downloaded file
+                println!("    Validating embedding model...");
+                match validation::validate_model_file(&embedding_path, 100 * 1024 * 1024) {
+                    Ok(_) => {
+                        ui::print_success(&format!("Downloaded: {}", embedding_path.display()));
+                        config.set_embedding_model(embedding_path.to_string_lossy().to_string())?;
+                    },
+                    Err(e) => {
+                        ui::print_error(&format!("Validation failed: {}", e));
+                        println!("    Deleting corrupted file...");
+                        let _ = std::fs::remove_file(&embedding_path);
+                        return Err(e);
+                    }
+                }
             }
 
             if !embedding_only {
@@ -894,9 +907,21 @@ fn run_models(action: ModelsAction, config: &mut Config) -> Result<()> {
                     .get("Qwen3-Reranker-0.6B-Q4_K_M.gguf")?;
 
                 pb.finish_and_clear();
-                ui::print_success(&format!("Downloaded: {}", reranker_path.display()));
-
-                config.set_reranker_model(reranker_path.to_string_lossy().to_string())?;
+
+                // Validate the downloaded file
+                println!("    Validating reranker model...");
+                match validation::validate_model_file(&reranker_path, 100 * 1024 * 1024) {
+                    Ok(_) => {
+                        ui::print_success(&format!("Downloaded: {}", reranker_path.display()));
+                        config.set_reranker_model(reranker_path.to_string_lossy().to_string())?;
+                    },
+                    Err(e) => {
+                        ui::print_error(&format!("Validation failed: {}", e));
+                        println!("    Deleting corrupted file...");
+                        let _ = std::fs::remove_file(&reranker_path);
+                        return Err(e);
+                    }
+                }
             }
 
             println!();

src/lib.rs

@@ -17,6 +17,7 @@ pub mod config;
 pub mod core;
 pub mod server;
 pub mod ui;
+pub mod utils;
 pub mod watcher;
 
 pub use config::Config;

src/utils/mod.rs

@@ -0,0 +1 @@
+pub mod validation;

src/utils/validation.rs

@@ -0,0 +1,33 @@
+use anyhow::{Result, Context};
+use std::fs;
+use std::path::Path;
+
+// Helper function to validate a model file
+pub fn validate_model_file(path: &Path, expected_size_min: u64) -> Result<()> {
+    // 1. Check if file exists
+    if !path.exists() {
+        anyhow::bail!("Model file does not exist at {}", path.display());
+    }
+
+    // 2. Check file size
+    let metadata = fs::metadata(path)?;
+    if metadata.len() < expected_size_min {
+        anyhow::bail!(
+            "Model file size too small: {} bytes (expected at least {})",
+            metadata.len(),
+            expected_size_min
+        );
+    }
+
+    // 3. Try to verify GGUF header (first 4 bytes should be 'GGUF')
+    let mut file = fs::File::open(path)?;
+    use std::io::Read;
+    let mut buffer = [0u8; 4];
+    file.read_exact(&mut buffer).context("Failed to read file header")?;
+
+    if &buffer != b"GGUF" {
+         anyhow::bail!("Invalid file format: Header is not 'GGUF'");
+    }
+
+    Ok(())
+}