package vm

import (
	"fmt"
	"qvm/internal/config"
	"qvm/internal/virtiofsd"
	"strconv"
)

// buildQEMUCommand builds the QEMU command line for virtiofsd-based mounts.
// Uses vhost-user-fs-pci devices which support hot-plugging.
func buildQEMUCommand(cfg *config.Config, sshPort int, mounts []virtiofsd.Mount) []string {
	memSize := cfg.VM.Memory

	// vhost-user-fs requires shared memory backend with share=on
	// We must specify memory size only via the memory backend and attach it to NUMA
	// The -m flag must match the memory backend size for QEMU to be happy
	args := []string{
		"-machine", "q35,memory-backend=mem",
		"-accel", "kvm",
		"-cpu", "host",
		"-object", fmt.Sprintf("memory-backend-memfd,id=mem,size=%s,share=on", memSize),
		"-smp", strconv.Itoa(cfg.VM.CPUs),
		"-display", "none",
		"-daemonize",
		"-pidfile", config.PIDFile,
		"-drive", fmt.Sprintf("file=%s,if=virtio,format=qcow2", config.Overlay),
		"-netdev", fmt.Sprintf("user,id=n0,hostfwd=tcp::%d-:22", sshPort),
		"-device", "virtio-net-pci,netdev=n0",
		"-serial", fmt.Sprintf("file:%s", config.SerialLog),
		"-qmp", fmt.Sprintf("unix:%s,server,nowait", config.QMPSocket),
	}

	// Add vhost-user-fs devices for each mount
	for _, mount := range mounts {
		args = append(args,
			"-chardev", fmt.Sprintf("socket,id=%s,path=%s", mount.Tag, mount.SocketPath),
			"-device", fmt.Sprintf("vhost-user-fs-pci,queue-size=1024,chardev=%s,tag=%s", mount.Tag, mount.Tag),
		)
	}

	return args
}