#!/bin/bash

set -e

echo "🛠️ Detecting OS..."
OS=$(uname -s)

is_wsl() {
  grep -qi microsoft /proc/version 2>/dev/null
}

install_docker_linux() {
  echo "🔧 Installing Docker on Linux..."

  # Remove old versions
  sudo apt-get remove -y docker docker-engine docker.io containerd runc || true

  # Install required tools
  echo "📦 Installing dependencies..."
  sudo apt-get update
  sudo apt-get install -y \
    ca-certificates \
    curl \
    gnupg \
    lsb-release \
    apt-transport-https

  # Ensure folders exist
  sudo mkdir -p /etc/apt/keyrings /etc/apt/sources.list.d

  # Add Docker GPG key
  echo "🔑 Adding Docker GPG key..."
  curl -fsSL https://download.docker.com/linux/$(. /etc/os-release && echo "$ID")/gpg | \
    sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
  sudo chmod a+r /etc/apt/keyrings/docker.gpg

  # Add Docker repository
  echo "📄 Adding Docker repository..."
  echo \
    "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] \
    https://download.docker.com/linux/$(. /etc/os-release && echo "$ID") \
    $(lsb_release -cs) stable" | \
    sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

  # Install Docker
  echo "📦 Installing Docker Engine & Compose..."
  sudo apt-get update
  sudo apt-get install -y \
    docker-ce \
    docker-ce-cli \
    containerd.io \
    docker-buildx-plugin \
    docker-compose-plugin

  if ! is_wsl; then
    echo "🔄 Enabling and starting Docker service..."
    sudo systemctl enable docker
    sudo systemctl start docker
  else
    echo "⚠️ Skipping systemctl steps (running in WSL)"
  fi

  echo "👥 Adding user '$USER' to docker group..."
  sudo usermod -aG docker "$USER"

  echo "✅ Docker installed successfully!"
  echo ""
  if is_wsl; then
    echo "🔁 Please restart your WSL session: run 'wsl --shutdown' in PowerShell or close your terminal."
  else
    echo "🔁 Please log out and log back in for the docker group to take effect."
  fi
}

install_docker_windows_message() {
  echo "🪟 Detected Windows system."
  echo "👉 Please install Docker Desktop from: https://www.docker.com/products/docker-desktop/"
  echo "It includes Docker Engine + Compose and integrates with WSL2."
  echo ""
  echo "Make sure to:"
  echo "  - Enable WSL2 backend during install"
  echo "  - Share your drives if needed (for volume mounting)"
}

case "$OS" in
  Linux)
    install_docker_linux
    ;;
  Darwin)
    echo "🍏 macOS detected. Please use Docker Desktop: https://www.docker.com/products/docker-desktop"
    ;;
  MINGW*|CYGWIN*|MSYS*|Windows_NT)
    install_docker_windows_message
    ;;
  *)
    echo "❌ Unsupported OS: $OS"
    exit 1
    ;;
esac