From 06e1c75e6322220d0176f6eb9f47682d366e99eb Mon Sep 17 00:00:00 2001
From: Jeremy Harris <jeremy.harris@zenosmosis.com>
Date: Wed, 3 Jan 2024 11:16:24 -0600
Subject: [PATCH] Add pipper shell (#17)

---
 README.md      |  5 +----
 pipper.sh      | 27 ++++++++++++++++++++++++---
 test_pipper.sh |  2 +-
 3 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/README.md b/README.md
index 7172982..3275469 100644
--- a/README.md
+++ b/README.md
@@ -17,16 +17,13 @@ Pipper: **P**ackage **I**nstaller and **P**ython **P**roject **E**nvironment **R
 Note: All commands can be run from *outside* of the virtual environment and will automatically launch as needed.
 
 - `pipper create`: Create a Python virtual environment. If you have more than one version of Python installed locally, you can do `pipper create python[python-version]`. (Note: Pipper uses the `venv` directory in your project and supports one environment at a time.)
+- `pipper shell`: Drops into a Bash sub-shell already configured with the virtual environment.
 - `pipper install`: Install ALL packages from a `requirements.txt` file (Note: if wanting to install a *specific* package, use `pip install [package-name]` instead).
 - `pipper freeze`: Freeze installed packages to update the `requirements.txt` file.
 - `pipper uninstall`: Uninstall ALL packages listed in the `requirements.txt` file (Note: if wanting to uninstall a *specific* package, use `pip uninstall [package-name]` instead).
 - `pipper run`: Run a Python script within the virtual environment.
 - `pipper test`: Run unit tests within the virtual environment (via `unittest`).
 
-*Optionally:*
-
-- `pipper activate`: Not generally needed because all other Pipper commands will handle this for you; when executing directly it provides CLI instructions on how to manually start the virtual environment.
-
 ## Getting Started
 
 ### Installation
diff --git a/pipper.sh b/pipper.sh
index 39843ad..f8a243e 100755
--- a/pipper.sh
+++ b/pipper.sh
@@ -42,6 +42,22 @@ create_venv() {
     activate_venv false
 }
 
+# Function to launch a sub-shell with the virtual environment activated.
+launch_venv_shell() {
+    if [ -d "$VENV_NAME" ]; then
+        echo "Launching a sub-shell with the virtual environment activated..."
+
+        # Define a command to activate the venv
+        ACTIVATE_VENV="source $VENV_NAME/bin/activate"
+
+        # Start a new shell instance with the venv activated
+        bash --init-file <(echo "$ACTIVATE_VENV; if [[ \$PS1 != *'($VENV_NAME)'* ]]; then PS1='($VENV_NAME) '\$PS1; fi")
+    else
+        echo "Virtual environment '$VENV_NAME' does not exist. Please create it first."
+    fi
+}
+
+
 # Function to activate the virtual environment.
 # Accepts a boolean argument to decide whether to activate it immediately.
 activate_venv() {
@@ -63,8 +79,9 @@ activate_venv() {
         source "$VENV_NAME/bin/activate"
     else
         # Display instructions on how to activate the environment manually.
-        echo "To activate the virtual environment, run:"
-        echo "source $VENV_NAME/bin/activate"
+        printf "\n\n"
+        echo "  To activate the virtual environment, run:"
+        echo "  pipper shell"
         printf "\n\n"
     fi
 }
@@ -157,6 +174,9 @@ case $1 in
     create)
         create_venv "$2"
         ;;
+    shell)
+        launch_venv_shell
+        ;;
     activate)
         activate_venv
         ;;
@@ -179,6 +199,7 @@ case $1 in
         run_tests_dry_run "$2" "$3"
         ;;
     *)
-        echo "Usage: $0 {create|activate|install|freeze|uninstall|run|test|test-dry-run}"
+        # Note: "activate" is intentionally not included, as it is primarily for testing
+        echo "Usage: $0 {create|shell|install|freeze|uninstall|run|test|test-dry-run}"
         ;;
 esac
diff --git a/test_pipper.sh b/test_pipper.sh
index 297f27e..526d83a 100755
--- a/test_pipper.sh
+++ b/test_pipper.sh
@@ -59,7 +59,7 @@ run_test "$PIPPER_SCRIPT create && dir_exists venv" "Create Virtual Environment
 
 # Test the activate_venv function (success is expected)
 activate_output=$($PIPPER_SCRIPT activate | tr -d '\n')
-expected_output="To activate the virtual environment, run:source venv/bin/activate"
+expected_output="  To activate the virtual environment, run:  pipper shell"
 run_test "[ \"$activate_output\" == \"$expected_output\" ]" "Activate Virtual Environment Test" 
 
 # Test the install_requirements function (success is expected)