supervisor_tree.nula

// Supervisor Tree — nested OTP supervisors with restart strategies.
// A root supervisor manages child supervisors and workers.
// Demonstrates the OTP built-in effect surface.
//
// Run with: nulang examples/supervisor_tree.nula

actor Worker {
    state id: Int = 0
    state healthy: Bool = true

    behavior init(worker_id: Int) {
        self.id = worker_id
        perform IO.print(
            "Worker " + perform Int.to_string(worker_id) + " started"
        )
    }

    behavior work(x: Int) {
        if self.healthy then
            perform IO.print(
                "Worker " + perform Int.to_string(self.id) +
                " processed " + perform Int.to_string(x)
            )
        else
            perform IO.print(
                "Worker " + perform Int.to_string(self.id) + " is sick, skipping"
            )
    }

    behavior sicken() {
        self.healthy = false
        perform IO.print(
            "Worker " + perform Int.to_string(self.id) + " is now sick"
        )
    }
}

fn main() {
    // Create a root supervisor (one_for_one strategy = 0)
    let root = perform Otp.create_supervisor("root", 0)

    // Create a simple-one-for-one child pool (strategy = 3)
    let pool = perform Otp.create_supervisor("worker_pool", 3)
    let t = perform Otp.set_template(pool, "Worker")

    // Start two workers from the template
    let w1 = perform Otp.start_child(pool)
    let w2 = perform Otp.start_child(pool)

    // Initialize and do work
    w1 ! init(1)
    w2 ! init(2)
    w1 ! work(10)
    w2 ! work(20)

    // Check count
    let count = perform Otp.child_count(pool)
    perform IO.print(
        "Active workers: " + perform Int.to_string(count)
    )

    // Terminate one worker normally
    let r = perform Otp.terminate_child(pool, w2)
    let count2 = perform Otp.child_count(pool)
    perform IO.print(
        "After terminate: " + perform Int.to_string(count2)
    )

    // Make worker 1 sick, then check it still exists (not killed)
    w1 ! sicken()
    w1 ! work(99)

    0
}