1 files changed, 86 insertions, 0 deletions
diff --git a/src/integration/mod.rs b/src/integration/mod.rs
new file mode 100644
index 00000000..65c5c6ad
--- /dev/null
+++ b/src/integration/mod.rs
@@ -0,0 +1,86 @@
+use std::fs;
+use std::io;
+use std::path::PathBuf;
+
+use portable_pty::CommandBuilder;
+
+use crate::layout::PaneId;
+
+pub(crate) const HERDR_PANE_ID_ENV_VAR: &str = "HERDR_PANE_ID";
+const PI_EXTENSION_INSTALL_NAME: &str = "herdr-agent-state.ts";
+const PI_EXTENSION_ASSET: &str = include_str!("assets/pi/herdr-agent-state.ts");
+
+pub(crate) fn apply_pane_env(cmd: &mut CommandBuilder, pane_id: PaneId) {
+    cmd.env(crate::api::SOCKET_PATH_ENV_VAR, crate::api::socket_path());
+    cmd.env(HERDR_PANE_ID_ENV_VAR, format!("p_{}", pane_id.raw()));
+}
+
+pub(crate) fn install_pi() -> io::Result<PathBuf> {
+    let dir = pi_extension_dir()?;
+    if !dir.is_dir() {
+        return Err(io::Error::other(format!(
+            "pi extension directory not found at {}. install pi and create the extensions directory first",
+            dir.display()
+        )));
+    }
+
+    let path = dir.join(PI_EXTENSION_INSTALL_NAME);
+    fs::write(&path, PI_EXTENSION_ASSET)?;
+    Ok(path)
+}
+
+fn pi_extension_dir() -> io::Result<PathBuf> {
+    let home = std::env::var("HOME")
+        .map(PathBuf::from)
+        .map_err(|_| io::Error::other("HOME is not set; cannot locate ~/.pi/agent/extensions"))?;
+    Ok(home.join(".pi/agent/extensions"))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn unique_base() -> PathBuf {
+        std::env::temp_dir().join(format!(
+            "herdr-integration-install-test-{}-{}",
+            std::process::id(),
+            std::time::SystemTime::now()
+                .duration_since(std::time::UNIX_EPOCH)
+                .unwrap()
+                .as_nanos()
+        ))
+    }
+
+    #[test]
+    fn install_pi_writes_embedded_asset_to_pi_extensions_dir() {
+        let base = unique_base();
+        let home = base.join("home");
+        let ext_dir = home.join(".pi/agent/extensions");
+        fs::create_dir_all(&ext_dir).unwrap();
+        std::env::set_var("HOME", &home);
+
+        let path = install_pi().unwrap();
+        let content = fs::read_to_string(&path).unwrap();
+
+        assert_eq!(path, ext_dir.join(PI_EXTENSION_INSTALL_NAME));
+        assert_eq!(content, PI_EXTENSION_ASSET);
+
+        std::env::remove_var("HOME");
+        let _ = fs::remove_dir_all(base);
+    }
+
+    #[test]
+    fn install_pi_errors_when_extension_dir_missing() {
+        let base = unique_base();
+        let home = base.join("home");
+        fs::create_dir_all(&home).unwrap();
+        std::env::set_var("HOME", &home);
+
+        let err = install_pi().unwrap_err().to_string();
+
+        assert!(err.contains("pi extension directory not found"));
+
+        std::env::remove_var("HOME");
+        let _ = fs::remove_dir_all(base);
+    }
+}