package main

import (
	"encoding/json"
	"errors"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"os/exec"
	"path"
	"strconv"
	"strings"
	"sync"
	"syscall"
	"time"

	kingpin "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/alecthomas/kingpin"
	serial "github.com/ipfs/go-ipfs/repo/fsrepo/serialize"

	ma "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-multiaddr"
	manet "github.com/ipfs/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-multiaddr-net"
)

// GetNumNodes returns the number of testbed nodes configured in the testbed directory
func GetNumNodes() int {
	for i := 0; i < 2000; i++ {
		_, err := os.Stat(IpfsDirN(i))
		if os.IsNotExist(err) {
			return i
		}
	}
	panic("i dont know whats going on")
}

func TestBedDir() string {
	tbd := os.Getenv("IPTB_ROOT")
	if len(tbd) != 0 {
		return tbd
	}

	home := os.Getenv("HOME")
	if len(home) == 0 {
		panic("could not find home")
	}

	return path.Join(home, "testbed")
}

func IpfsDirN(n int) string {
	return path.Join(TestBedDir(), fmt.Sprint(n))
}

func YesNoPrompt(prompt string) bool {
	var s string
	for {
		fmt.Println(prompt)
		fmt.Scanf("%s", &s)
		switch s {
		case "y", "Y":
			return true
		case "n", "N":
			return false
		}
		fmt.Println("Please press either 'y' or 'n'")
	}
}

type initCfg struct {
	Count     int
	Force     bool
	Bootstrap string
	PortStart int
	Mdns      bool
	Utp       bool
}

func (c *initCfg) swarmAddrForPeer(i int) string {
	str := "/ip4/0.0.0.0/tcp/%d"
	if c.Utp {
		str = "/ip4/0.0.0.0/udp/%d/utp"
	}

	if c.PortStart == 0 {
		return fmt.Sprintf(str, 0)
	}
	return fmt.Sprintf(str, c.PortStart+i)
}

func (c *initCfg) apiAddrForPeer(i int) string {
	if c.PortStart == 0 {
		return "/ip4/127.0.0.1/tcp/0"
	}
	return fmt.Sprintf("/ip4/127.0.0.1/tcp/%d", c.PortStart+1000+i)
}

func IpfsInit(cfg *initCfg) error {
	p := IpfsDirN(0)
	if _, err := os.Stat(p); !os.IsNotExist(err) {
		if !cfg.Force && !YesNoPrompt("testbed nodes already exist, overwrite? [y/n]") {
			return nil
		}
		err := os.RemoveAll(TestBedDir())
		if err != nil {
			return err
		}
	}
	wait := sync.WaitGroup{}
	for i := 0; i < cfg.Count; i++ {
		wait.Add(1)
		go func(v int) {
			defer wait.Done()
			dir := IpfsDirN(v)
			err := os.MkdirAll(dir, 0777)
			if err != nil {
				log.Println("ERROR: ", err)
				return
			}

			cmd := exec.Command("ipfs", "init", "-b=1024")
			cmd.Env = append(cmd.Env, "IPFS_PATH="+dir)
			out, err := cmd.CombinedOutput()
			if err != nil {
				log.Println("ERROR: ", err)
				log.Println(string(out))
			}
		}(i)
	}
	wait.Wait()

	// Now setup bootstrapping
	switch cfg.Bootstrap {
	case "star":
		err := starBootstrap(cfg)
		if err != nil {
			return err
		}
	case "none":
		err := clearBootstrapping(cfg)
		if err != nil {
			return err
		}
	default:
		return fmt.Errorf("unrecognized bootstrapping option: %s", cfg.Bootstrap)
	}

	return nil
}

func starBootstrap(icfg *initCfg) error {
	// '0' node is the bootstrap node
	cfgpath := path.Join(IpfsDirN(0), "config")
	bcfg, err := serial.Load(cfgpath)
	if err != nil {
		return err
	}
	bcfg.Bootstrap = nil
	bcfg.Addresses.Swarm = []string{icfg.swarmAddrForPeer(0)}
	bcfg.Addresses.API = icfg.apiAddrForPeer(0)
	bcfg.Addresses.Gateway = ""
	bcfg.Discovery.MDNS.Enabled = icfg.Mdns
	err = serial.WriteConfigFile(cfgpath, bcfg)
	if err != nil {
		return err
	}

	for i := 1; i < icfg.Count; i++ {
		cfgpath := path.Join(IpfsDirN(i), "config")
		cfg, err := serial.Load(cfgpath)
		if err != nil {
			return err
		}

		ba := fmt.Sprintf("%s/ipfs/%s", bcfg.Addresses.Swarm[0], bcfg.Identity.PeerID)
		ba = strings.Replace(ba, "0.0.0.0", "127.0.0.1", -1)
		cfg.Bootstrap = []string{ba}
		cfg.Addresses.Gateway = ""
		cfg.Discovery.MDNS.Enabled = icfg.Mdns
		cfg.Addresses.Swarm = []string{
			icfg.swarmAddrForPeer(i),
		}
		cfg.Addresses.API = icfg.apiAddrForPeer(i)
		err = serial.WriteConfigFile(cfgpath, cfg)
		if err != nil {
			return err
		}
	}
	return nil
}

func clearBootstrapping(icfg *initCfg) error {
	for i := 0; i < icfg.Count; i++ {
		cfgpath := path.Join(IpfsDirN(i), "config")
		cfg, err := serial.Load(cfgpath)
		if err != nil {
			return err
		}

		cfg.Bootstrap = nil
		cfg.Addresses.Gateway = ""
		cfg.Addresses.Swarm = []string{icfg.swarmAddrForPeer(i)}
		cfg.Addresses.API = icfg.apiAddrForPeer(i)
		cfg.Discovery.MDNS.Enabled = icfg.Mdns
		err = serial.WriteConfigFile(cfgpath, cfg)
		if err != nil {
			return err
		}
	}
	return nil
}

func IpfsPidOf(n int) (int, error) {
	dir := IpfsDirN(n)
	b, err := ioutil.ReadFile(path.Join(dir, "daemon.pid"))
	if err != nil {
		return -1, err
	}

	return strconv.Atoi(string(b))
}

func KillNode(i int) error {
	pid, err := IpfsPidOf(i)
	if err != nil {
		return fmt.Errorf("error killing daemon %d: %s", i, err)
	}

	p, err := os.FindProcess(pid)
	if err != nil {
		return fmt.Errorf("error killing daemon %d: %s", i, err)
	}
	err = p.Kill()
	if err != nil {
		return fmt.Errorf("error killing daemon %d: %s\n", i, err)
	}

	p.Wait()

	err = os.Remove(path.Join(IpfsDirN(i), "daemon.pid"))
	if err != nil {
		return fmt.Errorf("error removing pid file for daemon %d: %s\n", i, err)
	}

	return nil
}

func IpfsKillAll() error {
	n := GetNumNodes()
	for i := 0; i < n; i++ {
		err := KillNode(i)
		if err != nil {
			return err
		}
	}
	return nil
}

func envForDaemon(n int) []string {
	envs := os.Environ()
	npath := "IPFS_PATH=" + IpfsDirN(n)
	for i, e := range envs {
		p := strings.Split(e, "=")
		if p[0] == "IPFS_PATH" {
			envs[i] = npath
			return envs
		}
	}

	return append(envs, npath)
}

func IpfsStart(waitall bool) error {
	var addrs []string
	n := GetNumNodes()
	for i := 0; i < n; i++ {
		dir := IpfsDirN(i)
		cmd := exec.Command("ipfs", "daemon")
		cmd.Dir = dir
		cmd.Env = envForDaemon(i)

		cmd.SysProcAttr = &syscall.SysProcAttr{Setsid: true}

		stdout, err := os.Create(path.Join(dir, "daemon.stdout"))
		if err != nil {
			return err
		}

		stderr, err := os.Create(path.Join(dir, "daemon.stderr"))
		if err != nil {
			return err
		}

		cmd.Stdout = stdout
		cmd.Stderr = stderr

		err = cmd.Start()
		if err != nil {
			return err
		}
		pid := cmd.Process.Pid

		fmt.Printf("Started daemon %d, pid = %d\n", i, pid)
		err = ioutil.WriteFile(path.Join(dir, "daemon.pid"), []byte(fmt.Sprint(pid)), 0666)
		if err != nil {
			return err
		}

		// Make sure node 0 is up before starting the rest so
		// bootstrapping works properly
		cfg, err := serial.Load(path.Join(IpfsDirN(i), "config"))
		if err != nil {
			return err
		}

		maddr := ma.StringCast(cfg.Addresses.API)
		_, addr, err := manet.DialArgs(maddr)
		if err != nil {
			return err
		}

		addrs = append(addrs, addr)

		err = waitOnAPI(cfg.Identity.PeerID, i)
		if err != nil {
			return err
		}
	}
	if waitall {
		for i := 0; i < n; i++ {
			err := waitOnSwarmPeers(i)
			if err != nil {
				return err
			}
		}

	}
	return nil
}

func waitOnAPI(peerid string, nnum int) error {
	for i := 0; i < 50; i++ {
		err := tryAPICheck(peerid, nnum)
		if err == nil {
			return nil
		}
		time.Sleep(time.Millisecond * 200)
	}
	return fmt.Errorf("node %d failed to come online in given time period", nnum)
}

func getNodesAPIAddr(nnum int) (string, error) {
	addrb, err := ioutil.ReadFile(path.Join(IpfsDirN(nnum), "api"))
	if err != nil {
		return "", err
	}

	maddr, err := ma.NewMultiaddr(string(addrb))
	if err != nil {
		fmt.Println("error parsing multiaddr: ", err)
		return "", err
	}

	_, addr, err := manet.DialArgs(maddr)
	if err != nil {
		fmt.Println("error on multiaddr dialargs: ", err)
		return "", err
	}
	return addr, nil
}

func tryAPICheck(peerid string, nnum int) error {
	addr, err := getNodesAPIAddr(nnum)
	if err != nil {
		return err
	}

	resp, err := http.Get("http://" + addr + "/api/v0/id")
	if err != nil {
		return err
	}

	out := make(map[string]interface{})
	err = json.NewDecoder(resp.Body).Decode(&out)
	if err != nil {
		return fmt.Errorf("liveness check failed: %s", err)
	}

	id, ok := out["ID"]
	if !ok {
		return fmt.Errorf("liveness check failed: ID field not present in output")
	}

	idstr := id.(string)
	if idstr != peerid {
		return fmt.Errorf("liveness check failed: unexpected peer at endpoint")
	}

	return nil
}

func waitOnSwarmPeers(nnum int) error {
	addr, err := getNodesAPIAddr(nnum)
	if err != nil {
		return err
	}

	for i := 0; i < 50; i++ {
		resp, err := http.Get("http://" + addr + "/api/v0/swarm/peers")
		if err == nil {
			out := make(map[string]interface{})
			err := json.NewDecoder(resp.Body).Decode(&out)
			if err != nil {
				return fmt.Errorf("liveness check failed: %s", err)
			}

			peers := out["Strings"].([]interface{})
			if len(peers) == 0 {
				time.Sleep(time.Millisecond * 200)
				continue
			}

			return nil
		}
		time.Sleep(time.Millisecond * 200)
	}
	return fmt.Errorf("node at %s failed to bootstrap in given time period", addr)
}

// GetPeerID reads the config of node 'n' and returns its peer ID
func GetPeerID(n int) (string, error) {
	cfg, err := serial.Load(path.Join(IpfsDirN(n), "config"))
	if err != nil {
		return "", err
	}
	return cfg.Identity.PeerID, nil
}

// IpfsShell sets up environment variables for a new shell to more easily
// control the given daemon
func IpfsShell(n int) error {
	shell := os.Getenv("SHELL")
	if shell == "" {
		return fmt.Errorf("couldnt find shell!")
	}

	dir := IpfsDirN(n)
	nenvs := []string{"IPFS_PATH=" + dir}

	nnodes := GetNumNodes()
	for i := 0; i < nnodes; i++ {
		peerid, err := GetPeerID(i)
		if err != nil {
			return err
		}
		nenvs = append(nenvs, fmt.Sprintf("NODE%d=%s", i, peerid))
	}
	nenvs = append(os.Environ(), nenvs...)

	return syscall.Exec(shell, []string{shell}, nenvs)
}

func ConnectNodes(from, to int) error {
	if from == to {
		// skip connecting to self..
		return nil
	}
	fmt.Printf("connecting %d -> %d\n", from, to)
	cmd := exec.Command("ipfs", "id", "-f", "<addrs>")
	cmd.Env = []string{"IPFS_PATH=" + IpfsDirN(to)}
	out, err := cmd.Output()
	if err != nil {
		fmt.Println("ERR: ", string(out))
		return err
	}
	addr := strings.Split(string(out), "\n")[0]

	connectcmd := exec.Command("ipfs", "swarm", "connect", addr)
	connectcmd.Env = []string{"IPFS_PATH=" + IpfsDirN(from)}
	out, err = connectcmd.CombinedOutput()
	if err != nil {
		fmt.Println(string(out))
		return err
	}
	return nil
}

func parseRange(s string) ([]int, error) {
	if strings.HasPrefix(s, "[") && strings.HasSuffix(s, "]") {
		ranges := strings.Split(s[1:len(s)-1], ",")
		var out []int
		for _, r := range ranges {
			rng, err := expandDashRange(r)
			if err != nil {
				return nil, err
			}

			out = append(out, rng...)
		}
		return out, nil
	} else {
		i, err := strconv.Atoi(s)
		if err != nil {
			return nil, err
		}

		return []int{i}, nil
	}
}

func expandDashRange(s string) ([]int, error) {
	parts := strings.Split(s, "-")
	if len(parts) == 0 {
		i, err := strconv.Atoi(s)
		if err != nil {
			return nil, err
		}
		return []int{i}, nil
	}
	low, err := strconv.Atoi(parts[0])
	if err != nil {
		return nil, err
	}

	hi, err := strconv.Atoi(parts[1])
	if err != nil {
		return nil, err
	}

	var out []int
	for i := low; i <= hi; i++ {
		out = append(out, i)
	}
	return out, nil
}

func GetAttr(attr string, node int) (string, error) {
	switch attr {
	case "id":
		return GetPeerID(node)
	default:
		return "", errors.New("unrecognized attribute")
	}
}

var helptext = `Ipfs Testbed

Commands:
  init 
      creates and initializes 'n' repos

    Options:
      -n=[number of nodes]
      -f - force overwriting of existing nodes
      -bootstrap - select bootstrapping style for cluster
        choices: star, none

  start 
      starts up all testbed nodes

    Options:
      -wait - wait until daemons are fully initialized
  stop 
      kills all testbed nodes
  restart
      kills, then restarts all testbed nodes

  shell [n]
      execs your shell with environment variables set as follows:
          IPFS_PATH - set to testbed node n's IPFS_PATH
          NODE[x] - set to the peer ID of node x

  get [attribute] [node]
    get an attribute of the given node
    currently supports: "id"

Env Vars:

IPTB_ROOT:
  Used to specify the directory that nodes will be created in.
`

func handleErr(s string, err error) {
	if err != nil {
		fmt.Fprintln(os.Stderr, s, err)
		os.Exit(1)
	}
}

func main() {
	cfg := new(initCfg)
	kingpin.Flag("n", "number of ipfs nodes to initialize").Short('n').IntVar(&cfg.Count)
	kingpin.Flag("port", "port to start allocations from").Default("4002").Short('p').IntVar(&cfg.PortStart)
	kingpin.Flag("force", "force initialization (overwrite existing configs)").Short('f').BoolVar(&cfg.Force)
	kingpin.Flag("mdns", "turn on mdns for nodes").BoolVar(&cfg.Mdns)
	kingpin.Flag("bootstrap", "select bootstrapping style for cluster").Default("star").StringVar(&cfg.Bootstrap)
	kingpin.Flag("utp", "use utp for addresses").BoolVar(&cfg.Utp)

	wait := kingpin.Flag("wait", "wait for nodes to come fully online before exiting").Bool()

	var args []string
	kingpin.Arg("args", "arguments").StringsVar(&args)
	kingpin.Parse()

	switch args[0] {
	case "init":
		if cfg.Count == 0 {
			fmt.Printf("please specify number of nodes: '%s init -n 10'\n", os.Args[0])
			os.Exit(1)
		}
		err := IpfsInit(cfg)
		handleErr("ipfs init err: ", err)
	case "start":
		err := IpfsStart(*wait)
		handleErr("ipfs start err: ", err)
	case "stop", "kill":
		if len(args) > 1 {
			i, err := strconv.Atoi(args[1])
			if err != nil {
				fmt.Println("failed to parse node number: ", err)
				os.Exit(1)
			}
			err = KillNode(i)
			if err != nil {
				fmt.Println("failed to kill node: ", err)
			}
			return
		}
		err := IpfsKillAll()
		handleErr("ipfs kill err: ", err)
	case "restart":
		err := IpfsKillAll()
		handleErr("ipfs kill err: ", err)

		err = IpfsStart(*wait)
		handleErr("ipfs start err: ", err)
	case "shell":
		if len(args) < 2 {
			fmt.Println("please specify which node you want a shell for")
			os.Exit(1)
		}
		n, err := strconv.Atoi(args[1])
		handleErr("parse err: ", err)

		err = IpfsShell(n)
		handleErr("ipfs shell err: ", err)
	case "connect":
		if len(args) < 3 {
			fmt.Println("iptb connect [node] [node]")
			os.Exit(1)
		}

		from, err := parseRange(args[1])
		if err != nil {
			fmt.Printf("failed to parse: %s\n", err)
			return
		}

		to, err := parseRange(args[2])
		if err != nil {
			fmt.Printf("failed to parse: %s\n", err)
			return
		}

		for _, f := range from {
			for _, t := range to {
				err = ConnectNodes(f, t)
				if err != nil {
					fmt.Printf("failed to connect: %s\n", err)
					return
				}
			}
		}

	case "get":
		if len(args) < 3 {
			fmt.Println("iptb get [attr] [node]")
			os.Exit(1)
		}
		attr := args[1]
		num, err := strconv.Atoi(args[2])
		handleErr("error parsing node number: ", err)

		val, err := GetAttr(attr, num)
		handleErr("error getting attribute: ", err)
		fmt.Println(val)
	default:
		kingpin.Usage()
		fmt.Println(helptext)
		os.Exit(1)
	}
}