package main

import (
	"fmt"

	"libvirt.org/go/libvirt"
)

// Host holds information and acts as a connection handle for a Host
// If a connection is closed prematurely, will re-open the connection and
// try the attempted method again
type Host struct {
	HostName string

	conn     *libvirt.Connect
	close    chan struct{}
	closeErr chan error
}

// ConnectHost creates a host connection wrapper that can be used regularly
func ConnectHost(host string) (*Host, error) {
	h := &Host{
		HostName: host,
	}

	if err := h.connect(); err != nil {
		return nil, err
	}

	h.close = make(chan struct{})
	h.closeErr = make(chan error)

	go func() {
		defer close(h.closeErr)
		<-h.close
		_, err := h.conn.Close()
		h.closeErr <- err
	}()
	return h, nil
}

// connect creates a host connection
func (h *Host) connect() error {
	var err error
	h.conn, err = libvirt.NewConnect(
		fmt.Sprintf("qemu+ssh://%s/system", h.HostName),
	)
	return err
}

// GetGuestByName returns a GuestVM instance that exists on the given host
func (h *Host) GetGuestByName(name string) (*GuestVM, error) {
	if g, err := GetGuest(name, h.conn); err == nil {
		return g, nil
	} else {
		lverr, ok := err.(libvirt.Error)
		if ok && lverr.Code == libvirt.ERR_INVALID_CONN {
			// try again after creating a new connection
			return GetGuest(name, h.conn)
		}
		return nil, err
	}
}

// Close triggers closing the host connection
func (h *Host) Close() error {
	close(h.close)
	return <-h.closeErr
}