package raft

import (
	"reflect"
	"testing"
	"time"

	"github.com/coreos/etcd/Godeps/_workspace/src/code.google.com/p/go.net/context"
	"github.com/coreos/etcd/pkg"
	"github.com/coreos/etcd/raft/raftpb"
)

// TestNodeStep ensures that node.Step sends msgProp to propc chan
// and other kinds of messages to recvc chan.
func TestNodeStep(t *testing.T) {
	for i, msgn := range raftpb.MessageType_name {
		n := &node{
			propc: make(chan raftpb.Message, 1),
			recvc: make(chan raftpb.Message, 1),
		}
		msgt := raftpb.MessageType(i)
		n.Step(context.TODO(), raftpb.Message{Type: msgt})
		// Proposal goes to proc chan. Others go to recvc chan.
		if msgt == raftpb.MsgProp {
			select {
			case <-n.propc:
			default:
				t.Errorf("%d: cannot receive %s on propc chan", msgt, msgn)
			}
		} else {
			if msgt == raftpb.MsgBeat || msgt == raftpb.MsgHup {
				select {
				case <-n.recvc:
					t.Errorf("%d: step should ignore %s", msgt, msgn)
				default:
				}
			} else {
				select {
				case <-n.recvc:
				default:
					t.Errorf("%d: cannot receive %s on recvc chan", msgt, msgn)
				}
			}
		}
	}
}

// Cancel and Stop should unblock Step()
func TestNodeStepUnblock(t *testing.T) {
	// a node without buffer to block step
	n := &node{
		propc: make(chan raftpb.Message),
		done:  make(chan struct{}),
	}

	ctx, cancel := context.WithCancel(context.Background())
	stopFunc := func() { close(n.done) }

	tests := []struct {
		unblock func()
		werr    error
	}{
		{stopFunc, ErrStopped},
		{cancel, context.Canceled},
	}

	for i, tt := range tests {
		errc := make(chan error, 1)
		go func() {
			err := n.Step(ctx, raftpb.Message{Type: raftpb.MsgProp})
			errc <- err
		}()
		tt.unblock()
		select {
		case err := <-errc:
			if err != tt.werr {
				t.Errorf("#%d: err = %v, want %v", i, err, tt.werr)
			}
			//clean up side-effect
			if ctx.Err() != nil {
				ctx = context.TODO()
			}
			select {
			case <-n.done:
				n.done = make(chan struct{})
			default:
			}
		case <-time.After(time.Millisecond * 100):
			t.Errorf("#%d: failed to unblock step", i)
		}
	}
}

// TestBlockProposal ensures that node will block proposal when it does not
// know who is the current leader; node will accept proposal when it knows
// who is the current leader.
func TestBlockProposal(t *testing.T) {
	n := newNode()
	r := newRaft(1, []uint64{1}, 10, 1)
	go n.run(r)
	defer n.Stop()

	errc := make(chan error, 1)
	go func() {
		errc <- n.Propose(context.TODO(), []byte("somedata"))
	}()

	pkg.ForceGosched()
	select {
	case err := <-errc:
		t.Errorf("err = %v, want blocking", err)
	default:
	}

	n.Campaign(context.TODO())
	pkg.ForceGosched()
	select {
	case err := <-errc:
		if err != nil {
			t.Errorf("err = %v, want %v", err, nil)
		}
	default:
		t.Errorf("blocking proposal, want unblocking")
	}
}

func TestReadyContainUpdates(t *testing.T) {
	tests := []struct {
		rd       Ready
		wcontain bool
	}{
		{Ready{}, false},
		{Ready{SoftState: &SoftState{Lead: 1}}, true},
		{Ready{HardState: raftpb.HardState{Vote: 1}}, true},
		{Ready{Entries: make([]raftpb.Entry, 1, 1)}, true},
		{Ready{CommittedEntries: make([]raftpb.Entry, 1, 1)}, true},
		{Ready{Messages: make([]raftpb.Message, 1, 1)}, true},
		{Ready{Snapshot: raftpb.Snapshot{Index: 1}}, true},
	}

	for i, tt := range tests {
		if g := tt.rd.containsUpdates(); g != tt.wcontain {
			t.Errorf("#%d: containUpdates = %v, want %v", i, g, tt.wcontain)
		}
	}
}

func TestNode(t *testing.T) {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	cc := raftpb.ConfChange{Type: raftpb.ConfChangeAddNode, NodeID: 1}
	ccdata, err := cc.Marshal()
	if err != nil {
		t.Fatalf("unexpected marshal error: %v", err)
	}
	wants := []Ready{
		{
			SoftState: &SoftState{Lead: 1, Nodes: []uint64{1}, RemovedNodes: []uint64{}, RaftState: StateLeader},
			HardState: raftpb.HardState{Term: 1, Commit: 2},
			Entries: []raftpb.Entry{
				{},
				{Type: raftpb.EntryConfChange, Term: 1, Index: 1, Data: ccdata},
				{Term: 1, Index: 2},
			},
			CommittedEntries: []raftpb.Entry{
				{Type: raftpb.EntryConfChange, Term: 1, Index: 1, Data: ccdata},
				{Term: 1, Index: 2},
			},
		},
		{
			HardState:        raftpb.HardState{Term: 1, Commit: 3},
			Entries:          []raftpb.Entry{{Term: 1, Index: 3, Data: []byte("foo")}},
			CommittedEntries: []raftpb.Entry{{Term: 1, Index: 3, Data: []byte("foo")}},
		},
	}

	n := StartNode(1, []Peer{{ID: 1}}, 10, 1)
	n.ApplyConfChange(cc)
	n.Campaign(ctx)
	if g := <-n.Ready(); !reflect.DeepEqual(g, wants[0]) {
		t.Errorf("#%d: g = %+v,\n             w   %+v", 1, g, wants[0])
	}

	n.Propose(ctx, []byte("foo"))
	if g := <-n.Ready(); !reflect.DeepEqual(g, wants[1]) {
		t.Errorf("#%d: g = %+v,\n             w   %+v", 2, g, wants[1])
	}

	select {
	case rd := <-n.Ready():
		t.Errorf("unexpected Ready: %+v", rd)
	default:
	}
}

func TestNodeRestart(t *testing.T) {
	entries := []raftpb.Entry{
		{},
		{Term: 1, Index: 1},
		{Term: 1, Index: 2, Data: []byte("foo")},
	}
	st := raftpb.HardState{Term: 1, Commit: 1}

	want := Ready{
		HardState: emptyState,
		// commit upto index commit index in st
		CommittedEntries: entries[1 : st.Commit+1],
	}

	n := RestartNode(1, 10, 1, nil, st, entries)
	if g := <-n.Ready(); !reflect.DeepEqual(g, want) {
		t.Errorf("g = %+v,\n             w   %+v", g, want)
	}

	select {
	case rd := <-n.Ready():
		t.Errorf("unexpected Ready: %+v", rd)
	default:
	}
}

// TestCompacts ensures Node.Compact creates a correct raft snapshot and compacts
// the raft log (call raft.compact)
func TestNodeCompact(t *testing.T) {
	ctx := context.Background()
	n := newNode()
	r := newRaft(1, []uint64{1}, 10, 1)
	go n.run(r)

	n.Campaign(ctx)
	n.Propose(ctx, []byte("foo"))

	w := raftpb.Snapshot{
		Term:         1,
		Index:        2, // one nop + one proposal
		Data:         []byte("a snapshot"),
		Nodes:        []uint64{1},
		RemovedNodes: []uint64{},
	}

	pkg.ForceGosched()
	select {
	case <-n.Ready():
	default:
		t.Fatalf("unexpected proposal failure: unable to commit entry")
	}

	n.Compact(w.Index, w.Nodes, w.Data)
	pkg.ForceGosched()
	select {
	case rd := <-n.Ready():
		if !reflect.DeepEqual(rd.Snapshot, w) {
			t.Errorf("snap = %+v, want %+v", rd.Snapshot, w)
		}
	default:
		t.Fatalf("unexpected compact failure: unable to create a snapshot")
	}
	pkg.ForceGosched()
	// TODO: this test the run updates the snapi correctly... should be tested
	// separately with other kinds of updates
	select {
	case <-n.Ready():
		t.Fatalf("unexpected more ready")
	default:
	}
	n.Stop()

	if r.raftLog.offset != w.Index {
		t.Errorf("log.offset = %d, want %d", r.raftLog.offset, w.Index)
	}
}

func TestSoftStateEqual(t *testing.T) {
	tests := []struct {
		st *SoftState
		we bool
	}{
		{&SoftState{}, true},
		{&SoftState{Lead: 1}, false},
		{&SoftState{RaftState: StateLeader}, false},
		{&SoftState{ShouldStop: true}, false},
		{&SoftState{Nodes: []uint64{1, 2}}, false},
		{&SoftState{RemovedNodes: []uint64{1, 2}}, false},
	}
	for i, tt := range tests {
		if g := tt.st.equal(&SoftState{}); g != tt.we {
			t.Errorf("#%d, equal = %v, want %v", i, g, tt.we)
		}
	}
}

func TestIsHardStateEqual(t *testing.T) {
	tests := []struct {
		st raftpb.HardState
		we bool
	}{
		{emptyState, true},
		{raftpb.HardState{Vote: 1}, false},
		{raftpb.HardState{Commit: 1}, false},
		{raftpb.HardState{Term: 1}, false},
	}

	for i, tt := range tests {
		if isHardStateEqual(tt.st, emptyState) != tt.we {
			t.Errorf("#%d, equal = %v, want %v", i, isHardStateEqual(tt.st, emptyState), tt.we)
		}
	}
}