package svc

import "errors"

// Close is idempotent, including startup failure and graceful shutdown.
func (c *ServiceContext) Close() error {
	if c == nil {
		return nil
	}
	c.closeOnce.Do(func() {
		if c.Lifecycle != nil {
			c.Lifecycle.RequestShutdown(nil)
		}
		c.closeMu.Lock()
		c.closed = true
		cleanups := c.cleanups
		c.cleanups = nil
		c.closeMu.Unlock()
		for i := len(cleanups) - 1; i >= 0; i-- {
			c.closeErr = errors.Join(c.closeErr, cleanups[i]())
		}

	})
	return c.closeErr
}

// OnClose transfers a resource cleanup to this context immediately after creation.
// Hooks run once in reverse order, also when later initialization fails.
func (c *ServiceContext) OnClose(cleanup func() error) {
	if cleanup == nil {
		return
	}
	c.closeMu.Lock()
	defer c.closeMu.Unlock()
	if c.closed {
		panic("svc: register cleanup after Close")
	}
	c.cleanups = append(c.cleanups, cleanup)
}