package main

import (
	gocontext "context"
	"fmt"
	"strconv"
	"strings"
	"syscall"

	"github.com/containerd/containerd/api/services/execution"
	"github.com/pkg/errors"
	"github.com/urfave/cli"
)

var signalMap = map[string]syscall.Signal{
	"ABRT":   syscall.SIGABRT,
	"ALRM":   syscall.SIGALRM,
	"BUS":    syscall.SIGBUS,
	"CHLD":   syscall.SIGCHLD,
	"CLD":    syscall.SIGCLD,
	"CONT":   syscall.SIGCONT,
	"FPE":    syscall.SIGFPE,
	"HUP":    syscall.SIGHUP,
	"ILL":    syscall.SIGILL,
	"INT":    syscall.SIGINT,
	"IO":     syscall.SIGIO,
	"IOT":    syscall.SIGIOT,
	"KILL":   syscall.SIGKILL,
	"PIPE":   syscall.SIGPIPE,
	"POLL":   syscall.SIGPOLL,
	"PROF":   syscall.SIGPROF,
	"PWR":    syscall.SIGPWR,
	"QUIT":   syscall.SIGQUIT,
	"SEGV":   syscall.SIGSEGV,
	"STKFLT": syscall.SIGSTKFLT,
	"STOP":   syscall.SIGSTOP,
	"SYS":    syscall.SIGSYS,
	"TERM":   syscall.SIGTERM,
	"TRAP":   syscall.SIGTRAP,
	"TSTP":   syscall.SIGTSTP,
	"TTIN":   syscall.SIGTTIN,
	"TTOU":   syscall.SIGTTOU,
	"UNUSED": syscall.SIGUNUSED,
	"URG":    syscall.SIGURG,
	"USR1":   syscall.SIGUSR1,
	"USR2":   syscall.SIGUSR2,
	"VTALRM": syscall.SIGVTALRM,
	"WINCH":  syscall.SIGWINCH,
	"XCPU":   syscall.SIGXCPU,
	"XFSZ":   syscall.SIGXFSZ,
}

var killCommand = cli.Command{
	Name:  "kill",
	Usage: "signal a container",
	Flags: []cli.Flag{
		cli.StringFlag{
			Name:  "id",
			Usage: "id of the container",
		},
		cli.BoolFlag{
			Name:  "all, a",
			Usage: "send signal to all processes inside the container",
		},
	},
	Action: func(context *cli.Context) error {
		id := context.String("id")
		if id == "" {
			return errors.New("container id must be provided")
		}

		sigstr := context.Args().First()
		if sigstr == "" {
			sigstr = "SIGTERM"
		}

		signal, err := parseSignal(sigstr)
		if err != nil {
			return err
		}

		containers, err := getExecutionService(context)
		if err != nil {
			return err
		}
		killRequest := &execution.KillRequest{
			ID:     id,
			Signal: uint32(signal),
			All:    context.Bool("all"),
		}
		_, err = containers.Kill(gocontext.Background(), killRequest)
		if err != nil {
			return err
		}
		return nil
	},
}

func parseSignal(rawSignal string) (syscall.Signal, error) {
	s, err := strconv.Atoi(rawSignal)
	if err == nil {
		sig := syscall.Signal(s)
		for _, msig := range signalMap {
			if sig == msig {
				return sig, nil
			}
		}
		return -1, fmt.Errorf("unknown signal %q", rawSignal)
	}
	signal, ok := signalMap[strings.TrimPrefix(strings.ToUpper(rawSignal), "SIG")]
	if !ok {
		return -1, fmt.Errorf("unknown signal %q", rawSignal)
	}
	return signal, nil
}