#!/bin/bash
# This script uninstalls any existing Java installation and then installs Java 11,
# which is compatible with Gradle 6.7.
# It supports Linux (apt, yum, or dnf) and macOS (using Homebrew).

set -e  # Exit immediately if a command fails

# Uninstall Java on Linux
uninstall_java_linux() {
  if command -v apt-get >/dev/null 2>&1; then
    echo "Uninstalling Java on apt-based system..."
    sudo apt-get remove --purge -y default-jre openjdk-* || true
    sudo apt-get autoremove -y || true
  elif command -v yum >/dev/null 2>&1; then
    echo "Uninstalling Java on yum-based system..."
    sudo yum remove -y java-* || true
  elif command -v dnf >/dev/null 2>&1; then
    echo "Uninstalling Java on dnf-based system..."
    sudo dnf remove -y java-* || true
  else
    echo "No supported package manager found. Please uninstall Java manually."
    exit 1
  fi
}

# Uninstall Java on macOS
uninstall_java_macos() {
  if ! command -v brew >/dev/null 2>&1; then
    echo "Homebrew is not installed. Please uninstall Java manually."
    exit 1
  fi
  echo "Uninstalling Java using Homebrew..."
  brew uninstall --cask temurin@11 || echo "temurin@11 not installed via Homebrew; skipping."
}

# Install Java 11 on Linux
install_java_11_linux() {
  if command -v apt-get >/dev/null 2>&1; then
    echo "Installing OpenJDK 11 on apt-based system..."
    sudo apt-get update
    sudo apt-get install -y openjdk-11-jdk
  elif command -v yum >/dev/null 2>&1; then
    echo "Installing OpenJDK 11 on yum-based system..."
    sudo yum install -y java-11-openjdk
  elif command -v dnf >/dev/null 2>&1; then
    echo "Installing OpenJDK 11 on dnf-based system..."
    sudo dnf install -y java-11-openjdk
  else
    echo "No supported package manager found. Please install Java 11 manually."
    exit 1
  fi
}

# Install Java 11 on macOS using Homebrew
install_java_11_macos() {
  if ! command -v brew >/dev/null 2>&1; then
    echo "Homebrew is not installed. Please install Java 11 manually."
    exit 1
  fi
  echo "Installing OpenJDK 11 using Homebrew..."
  brew install --cask temurin@11
}

# Check if Java 11 is installed by verifying its version output
check_java_valid() {
  if java -version 2>&1 | grep -q '11'; then
    return 0
  else
    return 1
  fi
}

# Main script execution
os_type=$(uname)
echo "Detected OS: $os_type"

if [ "$os_type" = "Darwin" ]; then
  uninstall_java_macos
  install_java_11_macos
  # Set JAVA_HOME and update PATH for macOS
  if [ -x "/usr/libexec/java_home" ]; then
    export JAVA_HOME=$(/usr/libexec/java_home -v 11)
    export PATH="$JAVA_HOME/bin:$PATH"
    echo "JAVA_HOME set to $JAVA_HOME"
  fi
elif [ "$os_type" = "Linux" ]; then
  uninstall_java_linux
  install_java_11_linux
  # On Linux, you might need to update alternatives if multiple Java versions are installed.
else
  echo "Unsupported OS: $os_type. Please install Java 11 manually."
  exit 1
fi

echo "Verifying Java installation..."
if check_java_valid; then
  echo "Java 11 installed successfully."
else
  echo "Java 11 installation failed. Please check the installation and package names."
  exit 1
fi

# Execute the run.sh script if it exists and is executable
if [ -x "./run.sh" ]; then
  echo "Executing ./run.sh..."
  ./run.sh
else
  echo "./run.sh not found or is not executable."
  exit 1
fi