Detect jupyter correctly in script

* Remove after_install hook because it is redundant now

bin/pyenv-register-kernel

@@ -8,6 +8,17 @@
 # it will use the current active version. If there is more than one
 # active version, it will use the first one.
 
+# Function to check if a Python package is installed
+check_python_package_installed() {
+    local package=$1
+    PYENV_VERSION=$name pyenv exec pip list --disable-pip-version-check | grep -F "$package" > /dev/null
+    if [ $? -eq 0 ]; then
+        return 0
+    else
+        return 1
+    fi
+}
+
 set -e
 [ -n "$PYENV_DEBUG" ] && set -x
 
@@ -20,28 +31,18 @@ fi
 python=$(PYENV_VERSION=$name pyenv which python)
 
 # Check if Jupyter is installed
-if PYENV_VERSION=$name pyenv exec which jupyter >/dev/null; then
+if check_python_package_installed "jupyter"; then
     jupyter_dir=$(PYENV_VERSION=$name pyenv exec jupyter --data-dir)
     kernel_dir=${jupyter_dir}/kernels/pyenv_${name}
 
     echo "Installing jupyter kernel file $name for $python to $kernel_dir ..."
 
     echo "Upgrading (or installing) the ipykernel package for $name ..."
-    PYENV_VERSION=$name pyenv exec pip install -U ipykernel
-    PYENV_VERSION=$name pyenv exec pip install -U --no-deps ipywidgets
-
-    mkdir -p $kernel_dir
-
-    kernel_file=${kernel_dir}/kernel.json
-
-    cat > $kernel_file <<EOF
-{
-    "argv": [ "$python", "-m", "ipykernel", "-f", "{connection_file}" ],
-    "display_name": "$name",
-    "language": "python"
-}
-EOF
+    PYENV_VERSION=$name pyenv exec pip install -U --disable-pip-version-check ipykernel
+    PYENV_VERSION=$name pyenv exec pip install -U --no-deps --disable-pip-version-check ipywidgets
 
+    echo "Creating kernel..."
+    PYENV_VERSION=$name pyenv exec python -m ipykernel install --user --name pyenv_$name --display-name "pyenv_$name"
     echo "Kernel file created."
 else
     echo "Jupyter is not installed in the pyenv environment '$name'."

etc/pyenv.d/uninstall/remove-jupyter-kernel.bash

@@ -1,7 +1,23 @@
 #!/usr/bin/env bash
+env_name=$1
 
-if declare -Ff after_uninstall >/dev/null; then
-    after_uninstall 'rm -rf $(jupyter --data-dir)/kernels/${VERSION_NAME}'
+check_python_package_installed() {
+    local package=$1
+    PYENV_VERSION=$env_name pyenv exec pip list --disable-pip-version-check | grep -F "$package" > /dev/null
+    if [ $? -eq 0 ]; then
+        return 0
+    else
+        return 1
+    fi
+}
+
+if declare -Ff before_uninstall >/dev/null; then
+    if check_python_package_installed "jupyter"; then
+        jupyter_data_dir=$(PYENV_VERSION=$env_name pyenv exec jupyter --data-dir)
+        before_uninstall 'rm -rf ${jupyter_data_dir}/kernels/pyenv_${env_name}'
+    else
+        echo "Jupyter is not installed in the pyenv environment '${env_name}'."
+    fi
 else
     echo "pyenv: pyenv-jupyter-kernel plugin requires pyenv v0.1.0 or later" >&2
 fi