/*
   Copyright 2014 CoreOS, Inc.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package discovery

import (
	"errors"
	"math"
	"math/rand"
	"net/http"
	"reflect"
	"sort"
	"strconv"
	"testing"
	"time"

	"github.com/coreos/etcd/Godeps/_workspace/src/github.com/jonboulle/clockwork"
	"github.com/coreos/etcd/Godeps/_workspace/src/golang.org/x/net/context"
	"github.com/coreos/etcd/client"
)

const (
	maxRetryInTest = 3
)

func TestNewProxyFuncUnset(t *testing.T) {
	pf, err := newProxyFunc("")
	if pf != nil {
		t.Fatal("unexpected non-nil proxyFunc")
	}
	if err != nil {
		t.Fatalf("unexpected non-nil err: %v", err)
	}
}

func TestNewProxyFuncBad(t *testing.T) {
	tests := []string{
		"%%",
		"http://foo.com/%1",
	}
	for i, in := range tests {
		pf, err := newProxyFunc(in)
		if pf != nil {
			t.Errorf("#%d: unexpected non-nil proxyFunc", i)
		}
		if err == nil {
			t.Errorf("#%d: unexpected nil err", i)
		}
	}
}

func TestNewProxyFunc(t *testing.T) {
	tests := map[string]string{
		"bar.com":              "http://bar.com",
		"http://disco.foo.bar": "http://disco.foo.bar",
	}
	for in, w := range tests {
		pf, err := newProxyFunc(in)
		if pf == nil {
			t.Errorf("%s: unexpected nil proxyFunc", in)
			continue
		}
		if err != nil {
			t.Errorf("%s: unexpected non-nil err: %v", in, err)
			continue
		}
		g, err := pf(&http.Request{})
		if err != nil {
			t.Errorf("%s: unexpected non-nil err: %v", in, err)
		}
		if g.String() != w {
			t.Errorf("%s: proxyURL=%q, want %q", in, g, w)
		}

	}
}

func TestCheckCluster(t *testing.T) {
	cluster := "/prefix/1000"
	self := "/1000/1"

	tests := []struct {
		nodes []*client.Node
		index uint64
		werr  error
		wsize int
	}{
		{
			// self is in the size range
			[]*client.Node{
				{Key: "/1000/_config/size", Value: "3", CreatedIndex: 1},
				{Key: "/1000/_config/"},
				{Key: self, CreatedIndex: 2},
				{Key: "/1000/2", CreatedIndex: 3},
				{Key: "/1000/3", CreatedIndex: 4},
				{Key: "/1000/4", CreatedIndex: 5},
			},
			5,
			nil,
			3,
		},
		{
			// self is in the size range
			[]*client.Node{
				{Key: "/1000/_config/size", Value: "3", CreatedIndex: 1},
				{Key: "/1000/_config/"},
				{Key: "/1000/2", CreatedIndex: 2},
				{Key: "/1000/3", CreatedIndex: 3},
				{Key: self, CreatedIndex: 4},
				{Key: "/1000/4", CreatedIndex: 5},
			},
			5,
			nil,
			3,
		},
		{
			// self is out of the size range
			[]*client.Node{
				{Key: "/1000/_config/size", Value: "3", CreatedIndex: 1},
				{Key: "/1000/_config/"},
				{Key: "/1000/2", CreatedIndex: 2},
				{Key: "/1000/3", CreatedIndex: 3},
				{Key: "/1000/4", CreatedIndex: 4},
				{Key: self, CreatedIndex: 5},
			},
			5,
			ErrFullCluster,
			3,
		},
		{
			// self is not in the cluster
			[]*client.Node{
				{Key: "/1000/_config/size", Value: "3", CreatedIndex: 1},
				{Key: "/1000/_config/"},
				{Key: "/1000/2", CreatedIndex: 2},
				{Key: "/1000/3", CreatedIndex: 3},
			},
			3,
			nil,
			3,
		},
		{
			[]*client.Node{
				{Key: "/1000/_config/size", Value: "3", CreatedIndex: 1},
				{Key: "/1000/_config/"},
				{Key: "/1000/2", CreatedIndex: 2},
				{Key: "/1000/3", CreatedIndex: 3},
				{Key: "/1000/4", CreatedIndex: 4},
			},
			3,
			ErrFullCluster,
			3,
		},
		{
			// bad size key
			[]*client.Node{
				{Key: "/1000/_config/size", Value: "bad", CreatedIndex: 1},
			},
			0,
			ErrBadSizeKey,
			0,
		},
		{
			// no size key
			[]*client.Node{},
			0,
			ErrSizeNotFound,
			0,
		},
	}

	for i, tt := range tests {
		rs := make([]*client.Response, 0)
		if len(tt.nodes) > 0 {
			rs = append(rs, &client.Response{Node: tt.nodes[0], Index: tt.index})
			rs = append(rs, &client.Response{
				Node: &client.Node{
					Key:   cluster,
					Nodes: tt.nodes[1:],
				},
				Index: tt.index,
			})
		}
		c := &clientWithResp{rs: rs}
		d := discovery{cluster: cluster, id: 1, c: c}

		cRetry := &clientWithRetry{failTimes: 3}
		cRetry.rs = rs
		fc := clockwork.NewFakeClock()
		dRetry := discovery{cluster: cluster, id: 1, c: cRetry, clock: fc}

		for _, d := range []discovery{d, dRetry} {
			go func() {
				for i := uint(1); i <= maxRetryInTest; i++ {
					fc.BlockUntil(1)
					fc.Advance(time.Second * (0x1 << i))
				}
			}()
			ns, size, index, err := d.checkCluster()
			if err != tt.werr {
				t.Errorf("#%d: err = %v, want %v", i, err, tt.werr)
			}
			if reflect.DeepEqual(ns, tt.nodes) {
				t.Errorf("#%d: nodes = %v, want %v", i, ns, tt.nodes)
			}
			if size != tt.wsize {
				t.Errorf("#%d: size = %v, want %d", i, size, tt.wsize)
			}
			if index != tt.index {
				t.Errorf("#%d: index = %v, want %d", i, index, tt.index)
			}
		}
	}
}

func TestWaitNodes(t *testing.T) {
	all := client.Nodes{
		0: {Key: "/1000/1", CreatedIndex: 2},
		1: {Key: "/1000/2", CreatedIndex: 3},
		2: {Key: "/1000/3", CreatedIndex: 4},
	}

	tests := []struct {
		nodes client.Nodes
		rs    []*client.Response
	}{
		{
			all,
			[]*client.Response{},
		},
		{
			all[:1],
			[]*client.Response{
				{Node: &client.Node{Key: "/1000/2", CreatedIndex: 3}},
				{Node: &client.Node{Key: "/1000/3", CreatedIndex: 4}},
			},
		},
		{
			all[:2],
			[]*client.Response{
				{Node: &client.Node{Key: "/1000/3", CreatedIndex: 4}},
			},
		},
		{
			append(all, &client.Node{Key: "/1000/4", CreatedIndex: 5}),
			[]*client.Response{
				{Node: &client.Node{Key: "/1000/3", CreatedIndex: 4}},
			},
		},
	}

	for i, tt := range tests {
		// Basic case
		c := &clientWithResp{nil, &watcherWithResp{tt.rs}}
		d := &discovery{cluster: "1000", c: c}

		// Retry case
		retryScanResp := make([]*client.Response, 0)
		if len(tt.nodes) > 0 {
			retryScanResp = append(retryScanResp, &client.Response{
				Node: &client.Node{
					Key:   "1000",
					Value: strconv.Itoa(3),
				},
			})
			retryScanResp = append(retryScanResp, &client.Response{
				Node: &client.Node{
					Nodes: tt.nodes,
				},
			})
		}
		cRetry := &clientWithResp{
			rs: retryScanResp,
			w:  &watcherWithRetry{rs: tt.rs, failTimes: 2},
		}
		fc := clockwork.NewFakeClock()
		dRetry := &discovery{
			cluster: "1000",
			c:       cRetry,
			clock:   fc,
		}

		for _, d := range []*discovery{d, dRetry} {
			go func() {
				for i := uint(1); i <= maxRetryInTest; i++ {
					fc.BlockUntil(1)
					fc.Advance(time.Second * (0x1 << i))
				}
			}()
			g, err := d.waitNodes(tt.nodes, 3, 0) // we do not care about index in this test
			if err != nil {
				t.Errorf("#%d: err = %v, want %v", i, err, nil)
			}
			if !reflect.DeepEqual(g, all) {
				t.Errorf("#%d: all = %v, want %v", i, g, all)
			}
		}
	}
}

func TestCreateSelf(t *testing.T) {
	rs := []*client.Response{{Node: &client.Node{Key: "1000/1", CreatedIndex: 2}}}

	w := &watcherWithResp{rs}
	errw := &watcherWithErr{errors.New("watch err")}

	c := &clientWithResp{rs, w}
	errc := &clientWithErr{errors.New("create err"), w}
	errwc := &clientWithResp{rs, errw}

	tests := []struct {
		c    client.KeysAPI
		werr error
	}{
		// no error
		{c, nil},
		// client.create returns an error
		{errc, errc.err},
		// watcher.next retuens an error
		{errwc, errw.err},
	}

	for i, tt := range tests {
		d := discovery{cluster: "1000", c: tt.c}
		if err := d.createSelf(""); err != tt.werr {
			t.Errorf("#%d: err = %v, want %v", i, err, nil)
		}
	}
}

func TestNodesToCluster(t *testing.T) {
	nodes := client.Nodes{
		0: {Key: "/1000/1", Value: "1=1.1.1.1", CreatedIndex: 1},
		1: {Key: "/1000/2", Value: "2=2.2.2.2", CreatedIndex: 2},
		2: {Key: "/1000/3", Value: "3=3.3.3.3", CreatedIndex: 3},
	}
	w := "1=1.1.1.1,2=2.2.2.2,3=3.3.3.3"

	cluster := nodesToCluster(nodes)
	if !reflect.DeepEqual(cluster, w) {
		t.Errorf("cluster = %v, want %v", cluster, w)
	}
}

func TestSortableNodes(t *testing.T) {
	ns := client.Nodes{
		0: {CreatedIndex: 5},
		1: {CreatedIndex: 1},
		2: {CreatedIndex: 3},
		3: {CreatedIndex: 4},
	}
	// add some randomness
	for i := 0; i < 10000; i++ {
		ns = append(ns, &client.Node{CreatedIndex: uint64(rand.Int31())})
	}
	sns := sortableNodes{ns}
	sort.Sort(sns)
	cis := make([]int, 0)
	for _, n := range sns.Nodes {
		cis = append(cis, int(n.CreatedIndex))
	}
	if sort.IntsAreSorted(cis) != true {
		t.Errorf("isSorted = %v, want %v", sort.IntsAreSorted(cis), true)
	}
	cis = make([]int, 0)
	for _, n := range ns {
		cis = append(cis, int(n.CreatedIndex))
	}
	if sort.IntsAreSorted(cis) != true {
		t.Errorf("isSorted = %v, want %v", sort.IntsAreSorted(cis), true)
	}
}

func TestRetryFailure(t *testing.T) {
	nRetries = maxRetryInTest
	defer func() { nRetries = math.MaxUint32 }()

	cluster := "1000"
	c := &clientWithRetry{failTimes: 4}
	fc := clockwork.NewFakeClock()
	d := discovery{
		cluster: cluster,
		id:      1,
		c:       c,
		clock:   fc,
	}
	go func() {
		for i := uint(1); i <= maxRetryInTest; i++ {
			fc.BlockUntil(1)
			fc.Advance(time.Second * (0x1 << i))
		}
	}()
	if _, _, _, err := d.checkCluster(); err != ErrTooManyRetries {
		t.Errorf("err = %v, want %v", err, ErrTooManyRetries)
	}
}

type clientWithResp struct {
	rs []*client.Response
	w  client.Watcher
}

func (c *clientWithResp) Create(ctx context.Context, key string, value string, ttl time.Duration) (*client.Response, error) {
	if len(c.rs) == 0 {
		return &client.Response{}, nil
	}
	r := c.rs[0]
	c.rs = c.rs[1:]
	return r, nil
}

func (c *clientWithResp) Get(ctx context.Context, key string) (*client.Response, error) {
	if len(c.rs) == 0 {
		return &client.Response{}, client.ErrKeyNoExist
	}
	r := c.rs[0]
	c.rs = append(c.rs[1:], r)
	return r, nil
}

func (c *clientWithResp) Watch(key string, waitIndex uint64) client.Watcher {
	return c.w
}

func (c *clientWithResp) RecursiveWatch(key string, waitIndex uint64) client.Watcher {
	return c.w
}

type clientWithErr struct {
	err error
	w   client.Watcher
}

func (c *clientWithErr) Create(ctx context.Context, key string, value string, ttl time.Duration) (*client.Response, error) {
	return &client.Response{}, c.err
}

func (c *clientWithErr) Get(ctx context.Context, key string) (*client.Response, error) {
	return &client.Response{}, c.err
}

func (c *clientWithErr) Watch(key string, waitIndex uint64) client.Watcher {
	return c.w
}

func (c *clientWithErr) RecursiveWatch(key string, waitIndex uint64) client.Watcher {
	return c.w
}

type watcherWithResp struct {
	rs []*client.Response
}

func (w *watcherWithResp) Next(context.Context) (*client.Response, error) {
	if len(w.rs) == 0 {
		return &client.Response{}, nil
	}
	r := w.rs[0]
	w.rs = w.rs[1:]
	return r, nil
}

type watcherWithErr struct {
	err error
}

func (w *watcherWithErr) Next(context.Context) (*client.Response, error) {
	return &client.Response{}, w.err
}

// clientWithRetry will timeout all requests up to failTimes
type clientWithRetry struct {
	clientWithResp
	failCount int
	failTimes int
}

func (c *clientWithRetry) Create(ctx context.Context, key string, value string, ttl time.Duration) (*client.Response, error) {
	if c.failCount < c.failTimes {
		c.failCount++
		return nil, client.ErrTimeout
	}
	return c.clientWithResp.Create(ctx, key, value, ttl)
}

func (c *clientWithRetry) Get(ctx context.Context, key string) (*client.Response, error) {
	if c.failCount < c.failTimes {
		c.failCount++
		return nil, client.ErrTimeout
	}
	return c.clientWithResp.Get(ctx, key)
}

// watcherWithRetry will timeout all requests up to failTimes
type watcherWithRetry struct {
	rs        []*client.Response
	failCount int
	failTimes int
}

func (w *watcherWithRetry) Next(context.Context) (*client.Response, error) {
	if w.failCount < w.failTimes {
		w.failCount++
		return nil, client.ErrTimeout
	}
	if len(w.rs) == 0 {
		return &client.Response{}, nil
	}
	r := w.rs[0]
	w.rs = w.rs[1:]
	return r, nil
}