package etcd

import (
	"fmt"
	"math/rand"
	"net/http"
	"net/http/httptest"
	"net/url"
	"testing"
	"time"

	"github.com/coreos/etcd/config"
	"github.com/coreos/etcd/store"
)

func TestMultipleNodes(t *testing.T) {
	tests := []int{1, 3, 5, 9, 11}

	for _, tt := range tests {
		es, hs := buildCluster(tt, false)
		waitCluster(t, es)
		for i := range es {
			es[len(es)-i-1].Stop()
		}
		for i := range hs {
			hs[len(hs)-i-1].Close()
		}
	}
	afterTest(t)
}

func TestMultipleTLSNodes(t *testing.T) {
	tests := []int{1, 3, 5}

	for _, tt := range tests {
		es, hs := buildCluster(tt, true)
		waitCluster(t, es)
		for i := range es {
			es[len(es)-i-1].Stop()
		}
		for i := range hs {
			hs[len(hs)-i-1].Close()
		}
	}
	afterTest(t)
}

func TestV2Redirect(t *testing.T) {
	es, hs := buildCluster(3, false)
	waitCluster(t, es)
	u := hs[1].URL
	ru := fmt.Sprintf("%s%s", hs[0].URL, "/v2/keys/foo")
	tc := NewTestClient()

	v := url.Values{}
	v.Set("value", "XXX")
	resp, _ := tc.PutForm(fmt.Sprintf("%s%s", u, "/v2/keys/foo"), v)
	if resp.StatusCode != http.StatusTemporaryRedirect {
		t.Errorf("status = %d, want %d", resp.StatusCode, http.StatusTemporaryRedirect)
	}
	location, err := resp.Location()
	if err != nil {
		t.Errorf("want err = %, want nil", err)
	}

	if location.String() != ru {
		t.Errorf("location = %v, want %v", location.String(), ru)
	}

	resp.Body.Close()
	for i := range es {
		es[len(es)-i-1].Stop()
	}
	for i := range hs {
		hs[len(hs)-i-1].Close()
	}
	afterTest(t)
}

func TestAdd(t *testing.T) {
	tests := []int{3, 4, 5, 6}

	for _, tt := range tests {
		es := make([]*Server, tt)
		hs := make([]*httptest.Server, tt)
		for i := 0; i < tt; i++ {
			c := config.New()
			if i > 0 {
				c.Peers = []string{hs[0].URL}
			}
			es[i], hs[i] = initTestServer(c, int64(i), false)
		}

		go es[0].Run()
		waitMode(participantMode, es[0])

		for i := 1; i < tt; i++ {
			id := int64(i)
			for {
				lead := es[0].p.node.Leader()
				if lead == -1 {
					time.Sleep(defaultElection * es[0].tickDuration)
					continue
				}

				err := es[lead].p.add(id, es[id].raftPubAddr, es[id].pubAddr)
				if err == nil {
					break
				}
				switch err {
				case tmpErr:
					time.Sleep(defaultElection * es[0].tickDuration)
				case raftStopErr, stopErr:
					t.Fatalf("#%d on %d: unexpected stop", i, lead)
				default:
					t.Fatal(err)
				}
			}
			go es[i].Run()
			waitMode(participantMode, es[i])

			for j := 0; j <= i; j++ {
				p := fmt.Sprintf("%s/%d", v2machineKVPrefix, id)
				w, err := es[j].p.Watch(p, false, false, 1)
				if err != nil {
					t.Errorf("#%d on %d: %v", i, j, err)
					break
				}
				<-w.EventChan
			}
		}

		for i := range hs {
			es[len(hs)-i-1].Stop()
		}
		for i := range hs {
			hs[len(hs)-i-1].Close()
		}
	}
	afterTest(t)
}

func TestRemove(t *testing.T) {
	tests := []int{3, 4, 5, 6}

	for k, tt := range tests {
		es, hs := buildCluster(tt, false)
		waitCluster(t, es)

		lead, _ := waitLeader(es)
		config := config.NewClusterConfig()
		config.ActiveSize = 0
		if err := es[lead].p.setClusterConfig(config); err != nil {
			t.Fatalf("#%d: setClusterConfig err = %v", k, err)
		}

		// we don't remove the machine from 2-node cluster because it is
		// not 100 percent safe in our raft.
		// TODO(yichengq): improve it later.
		for i := 0; i < tt-2; i++ {
			id := int64(i)
			send := id
			for {
				send++
				if send > int64(tt-1) {
					send = id
				}

				lead := es[send].p.node.Leader()
				if lead == -1 {
					time.Sleep(defaultElection * 5 * time.Millisecond)
					continue
				}

				err := es[lead].p.remove(id)
				if err == nil {
					break
				}
				switch err {
				case tmpErr:
					time.Sleep(defaultElection * 5 * time.Millisecond)
				case raftStopErr, stopErr:
					if lead == id {
						break
					}
				default:
					t.Fatal(err)
				}

			}

			waitMode(standbyMode, es[i])
		}

		for i := range es {
			es[len(hs)-i-1].Stop()
		}
		for i := range hs {
			hs[len(hs)-i-1].Close()
		}
	}
	afterTest(t)
	// ensure that no goroutines are running
	TestGoroutinesRunning(t)
}

func TestBecomeStandby(t *testing.T) {
	size := 5
	round := 1

	for j := 0; j < round; j++ {
		es, hs := buildCluster(size, false)
		waitCluster(t, es)

		lead, _ := waitActiveLeader(es)
		i := rand.Intn(size)
		// cluster only demotes follower
		if int64(i) == lead {
			i = (i + 1) % size
		}
		id := int64(i)

		config := config.NewClusterConfig()
		config.SyncInterval = 1000

		config.ActiveSize = size - 1
		if err := es[lead].p.setClusterConfig(config); err != nil {
			t.Fatalf("#%d: setClusterConfig err = %v", i, err)
		}
		if err := es[lead].p.remove(id); err != nil {
			t.Fatalf("#%d: remove err = %v", i, err)
		}

		waitMode(standbyMode, es[i])

		for k := 0; k < 4; k++ {
			if es[i].s.leader != noneId {
				break
			}
			time.Sleep(20 * time.Millisecond)
		}
		if g := es[i].s.leader; g != lead {
			t.Errorf("#%d: lead = %d, want %d", i, g, lead)
		}

		for i := range hs {
			es[len(hs)-i-1].Stop()
		}
		for i := range hs {
			hs[len(hs)-i-1].Close()
		}
	}
	afterTest(t)
}

// TODO(yichengq): cannot handle previous msgDenial correctly now
func TestModeSwitch(t *testing.T) {
	t.Skip("not passed")
	size := 5
	round := 3

	for i := 0; i < size; i++ {
		es, hs := buildCluster(size, false)
		waitCluster(t, es)

		config := config.NewClusterConfig()
		config.SyncInterval = 0
		id := int64(i)
		for j := 0; j < round; j++ {
			lead, _ := waitActiveLeader(es)
			// cluster only demotes follower
			if lead == id {
				continue
			}

			config.ActiveSize = size - 1
			if err := es[lead].p.setClusterConfig(config); err != nil {
				t.Fatalf("#%d: setClusterConfig err = %v", i, err)
			}
			if err := es[lead].p.remove(id); err != nil {
				t.Fatalf("#%d: remove err = %v", i, err)
			}

			waitMode(standbyMode, es[i])

			for k := 0; k < 4; k++ {
				if es[i].s.leader != noneId {
					break
				}
				time.Sleep(20 * time.Millisecond)
			}
			if g := es[i].s.leader; g != lead {
				t.Errorf("#%d: lead = %d, want %d", i, g, lead)
			}

			config.ActiveSize = size
			if err := es[lead].p.setClusterConfig(config); err != nil {
				t.Fatalf("#%d: setClusterConfig err = %v", i, err)
			}

			waitMode(participantMode, es[i])

			if err := checkParticipant(i, es); err != nil {
				t.Errorf("#%d: check alive err = %v", i, err)
			}
		}

		for i := range hs {
			es[len(hs)-i-1].Stop()
		}
		for i := range hs {
			hs[len(hs)-i-1].Close()
		}
	}
	afterTest(t)
}

func buildCluster(number int, tls bool) ([]*Server, []*httptest.Server) {
	bootstrapper := 0
	es := make([]*Server, number)
	hs := make([]*httptest.Server, number)
	var seed string

	for i := range es {
		c := config.New()
		if seed != "" {
			c.Peers = []string{seed}
		}
		es[i], hs[i] = initTestServer(c, int64(i), tls)

		if i == bootstrapper {
			seed = hs[i].URL
		} else {
			// wait for the previous configuration change to be committed
			// or this configuration request might be dropped
			w, err := es[0].p.Watch(v2machineKVPrefix, true, false, uint64(i))
			if err != nil {
				panic(err)
			}
			<-w.EventChan
		}
		go es[i].Run()
		waitMode(participantMode, es[i])
	}
	return es, hs
}

func initTestServer(c *config.Config, id int64, tls bool) (e *Server, h *httptest.Server) {
	e = New(c, id)
	e.SetTick(time.Millisecond * 5)
	m := http.NewServeMux()
	m.Handle("/", e)
	m.Handle("/raft", e.RaftHandler())
	m.Handle("/raft/", e.RaftHandler())

	if tls {
		h = httptest.NewTLSServer(m)
	} else {
		h = httptest.NewServer(m)
	}

	e.raftPubAddr = h.URL
	e.pubAddr = h.URL
	return
}

func waitCluster(t *testing.T, es []*Server) {
	n := len(es)
	for i, e := range es {
		var index uint64
		for k := 0; k < n; k++ {
			index++
			w, err := e.p.Watch(v2machineKVPrefix, true, false, index)
			if err != nil {
				panic(err)
			}
			v := <-w.EventChan
			// join command may appear several times due to retry
			// when timeout
			if k > 0 {
				pw := fmt.Sprintf("%s/%d", v2machineKVPrefix, k-1)
				if v.Node.Key == pw {
					continue
				}
			}
			ww := fmt.Sprintf("%s/%d", v2machineKVPrefix, k)
			if v.Node.Key != ww {
				t.Errorf("#%d path = %v, want %v", i, v.Node.Key, ww)
			}
		}
	}
}

func waitMode(mode int64, e *Server) {
	for {
		if e.mode.Get() == mode {
			return
		}
		time.Sleep(10 * time.Millisecond)
	}
}

// checkParticipant checks the i-th server works well as participant.
func checkParticipant(i int, es []*Server) error {
	lead, _ := waitActiveLeader(es)
	key := fmt.Sprintf("/%d", rand.Int31())
	ev, err := es[lead].p.Set(key, false, "bar", store.Permanent)
	if err != nil {
		return err
	}

	w, err := es[i].p.Watch(key, false, false, ev.Index())
	if err != nil {
		return err
	}
	select {
	case <-w.EventChan:
	case <-time.After(8 * defaultHeartbeat * es[i].tickDuration):
		return fmt.Errorf("watch timeout")
	}
	return nil
}