// Import the package.
import Lifecycle

// Initialize the `Lifecycle` container.
var lifecycle = ServiceLifecycle()

// Register a resource that should be shut down when the application exits.
//
// In this case, we are registering a SwiftNIO `EventLoopGroup`
// and passing its `syncShutdownGracefully` function to be called on shutdown.
let eventLoopGroup = MultiThreadedEventLoopGroup(numberOfThreads: System.coreCount)
lifecycle.registerShutdown(
    name: "eventLoopGroup",
    .sync(eventLoopGroup.syncShutdownGracefully)
)

// Register another resource that should be started when the application starts
// and shut down when the application exits.
//
// In this case, we are registering a contrived `DatabaseMigrator`
// and passing its `migrate` function to be called on startup
// and `shutdown` function to be called on shutdown.
let migrator = DatabaseMigrator(eventLoopGroup: eventLoopGroup)
lifecycle.register(
    name: "migrator",
    start: .async(migrator.migrate),
    shutdown: .async(migrator.shutdown)
)

// Start the application.
//
// Start handlers passed using the `register` function
// will be called in the order they were registered in.
lifecycle.start() { error in
    // start completion handler
    // if an startup error occurred you can capture it here
    if let error = error {
        logger.error("failed starting \(self) ☠️: \(error)")
    } else {
        logger.info("\(self) started successfully 🚀")
    }
}

// Wait for the application to exit
//
// This is a blocking operation that typically waits for a `Signal`.
// The `Signal` can be configured at `lifecycle.init`, and defaults to `INT` and `TERM`.
// Shutdown handlers passed using the `register` or `registerShutdown` functions
// will be called in the reverse order they were registered in.
lifecycle.wait()