#!/bin/bash
set -euo pipefail

echo "============================================"
echo "Python 3 Latest Installation Script"
echo "============================================"
echo ""
echo "This script will run the following commands with sudo:"
echo "  - apt-get update"
echo "  - apt-get install -y software-properties-common"
echo "  - add-apt-repository -y ppa:deadsnakes/ppa"
echo "  - apt-get update"
echo "  - apt-get install -y python3.X python3.X-venv python3.X-dev python3.X-distutils"
echo "  - <latest-python> (to install pip via get-pip.py)"
echo ""
read -p "Continue with installation? (y/N) " -n 1 -r
echo
if [[ ! $REPLY =~ ^[Yy]$ ]]; then
    echo "Installation cancelled."
    exit 0
fi

echo ""
echo "Starting installation (commands will be shown as they run)..."
echo ""

# Enable command tracing
set -x

# Install prerequisites
sudo apt-get update
sudo apt-get install -y software-properties-common

# Add deadsnakes PPA
sudo add-apt-repository -y ppa:deadsnakes/ppa
sudo apt-get update

# Disable tracing temporarily to find latest version cleanly
set +x

# Find the latest Python 3 version available
echo "Finding latest Python 3 version..."
LATEST_PYTHON=$(apt-cache search --names-only '^python3\.[0-9]+$' | \
    grep -oP 'python3\.\d+' | \
    sort -V | \
    tail -1)

if [ -z "$LATEST_PYTHON" ]; then
    echo "Error: Could not determine latest Python 3 version" >&2
    exit 1
fi

echo "Installing $LATEST_PYTHON..."
set -x

sudo apt-get install -y \
    "$LATEST_PYTHON" \
    "$LATEST_PYTHON-venv" \
    "$LATEST_PYTHON-dev" \
    "$LATEST_PYTHON-distutils"

# Install pip for the new Python version
curl -sS https://bootstrap.pypa.io/get-pip.py | sudo "$LATEST_PYTHON"

# Disable command tracing for cleaner output
set +x

echo ""
echo "============================================"
# Verify installation
if command -v "$LATEST_PYTHON" &> /dev/null; then
    echo "$LATEST_PYTHON installed successfully!"
    "$LATEST_PYTHON" --version
    "$LATEST_PYTHON" -m pip --version
else
    echo "Error: $LATEST_PYTHON installation failed" >&2
    exit 1
fi
echo ""
echo "Note: Use '$LATEST_PYTHON' to run this version"
echo "To make it the default python3, run:"
echo "  sudo update-alternatives --install /usr/bin/python3 python3 /usr/bin/$LATEST_PYTHON 1"
echo "============================================"