package fleet

import (
	"fmt"
	"os"
	"os/exec"
	"strings"
	"syscall"

	"github.com/coreos/fleet/machine"
	"github.com/coreos/fleet/ssh"
)

// runCommand will attempt to run a command on a given machine. It will attempt
// to SSH to the machine if it is identified as being remote.
func runCommand(cmd string, machID string) (retcode int) {
	var err error
	if machine.IsLocalMachineID(machID) {
		err, retcode = runLocalCommand(cmd)
		if err != nil {
			fmt.Printf("Error running local command: %v\n", err)
		}
	} else {
		ms, err := machineState(machID)
		if err != nil || ms == nil {
			fmt.Printf("Error getting machine IP: %v\n", err)
		} else {
			err, retcode = runRemoteCommand(cmd, ms.PublicIP)
			if err != nil {
				fmt.Printf("Error running remote command: %v\n", err)
			}
		}
	}
	return
}

// runLocalCommand runs the given command locally and returns any error encountered and the exit code of the command
func runLocalCommand(cmd string) (error, int) {
	cmdSlice := strings.Split(cmd, " ")
	osCmd := exec.Command(cmdSlice[0], cmdSlice[1:]...)
	osCmd.Stderr = os.Stderr
	osCmd.Stdout = os.Stdout
	osCmd.Start()
	err := osCmd.Wait()
	if err != nil {
		// Get the command's exit status if we can
		if exiterr, ok := err.(*exec.ExitError); ok {
			if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
				return nil, status.ExitStatus()
			}
		}
		// Otherwise, generic command error
		return err, -1
	}
	return nil, 0
}

// runRemoteCommand runs the given command over SSH on the given IP, and returns
// any error encountered and the exit status of the command
func runRemoteCommand(cmd string, addr string) (err error, exit int) {
	var sshClient *ssh.SSHForwardingClient
	if tun := getTunnelFlag(); tun != "" {
		sshClient, err = ssh.NewTunnelledSSHClient("core", tun, addr, getChecker(), false)
	} else {
		sshClient, err = ssh.NewSSHClient("core", addr, getChecker(), false)
	}
	if err != nil {
		return err, -1
	}

	defer sshClient.Close()

	return ssh.Execute(sshClient, cmd)
}

func machineState(machID string) (*machine.MachineState, error) {
	machines, err := cAPI.Machines()
	if err != nil {
		return nil, err
	}
	for _, ms := range machines {
		if ms.ID == machID {
			return &ms, nil
		}
	}
	return nil, nil
}

// cachedMachineState makes a best-effort to retrieve the MachineState of the given machine ID.
// It memoizes MachineState information for the life of a fleetctl invocation.
// Any error encountered retrieving the list of machines is ignored.
func cachedMachineState(machID string) (ms *machine.MachineState) {
	if machineStates == nil {
		machineStates = make(map[string]*machine.MachineState)
		ms, err := cAPI.Machines()
		if err != nil {
			return nil
		}
		for i, m := range ms {
			machineStates[m.ID] = &ms[i]
		}
	}
	return machineStates[machID]
}