// Copyright 2015 The etcd Authors
//
// 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 tracker

import (
	"testing"
)

func TestProgressString(t *testing.T) {
	ins := NewInflights(1)
	ins.Add(123)
	pr := &Progress{
		Match:           1,
		Next:            2,
		State:           StateSnapshot,
		PendingSnapshot: 123,
		RecentActive:    false,
		ProbeSent:       true,
		IsLearner:       true,
		Inflights:       ins,
	}
	const exp = `StateSnapshot match=1 next=2 learner paused pendingSnap=123 inactive inflight=1[full]`
	if act := pr.String(); act != exp {
		t.Errorf("exp: %s\nact: %s", exp, act)
	}
}

func TestProgressIsPaused(t *testing.T) {
	tests := []struct {
		state  StateType
		paused bool

		w bool
	}{
		{StateProbe, false, false},
		{StateProbe, true, true},
		{StateReplicate, false, false},
		{StateReplicate, true, false},
		{StateSnapshot, false, true},
		{StateSnapshot, true, true},
	}
	for i, tt := range tests {
		p := &Progress{
			State:     tt.state,
			ProbeSent: tt.paused,
			Inflights: NewInflights(256),
		}
		if g := p.IsPaused(); g != tt.w {
			t.Errorf("#%d: paused= %t, want %t", i, g, tt.w)
		}
	}
}

// TestProgressResume ensures that MaybeUpdate and MaybeDecrTo will reset
// ProbeSent.
func TestProgressResume(t *testing.T) {
	p := &Progress{
		Next:      2,
		ProbeSent: true,
	}
	p.MaybeDecrTo(1, 1)
	if p.ProbeSent {
		t.Errorf("paused= %v, want false", p.ProbeSent)
	}
	p.ProbeSent = true
	p.MaybeUpdate(2)
	if p.ProbeSent {
		t.Errorf("paused= %v, want false", p.ProbeSent)
	}
}

func TestProgressBecomeProbe(t *testing.T) {
	match := uint64(1)
	tests := []struct {
		p     *Progress
		wnext uint64
	}{
		{
			&Progress{State: StateReplicate, Match: match, Next: 5, Inflights: NewInflights(256)},
			2,
		},
		{
			// snapshot finish
			&Progress{State: StateSnapshot, Match: match, Next: 5, PendingSnapshot: 10, Inflights: NewInflights(256)},
			11,
		},
		{
			// snapshot failure
			&Progress{State: StateSnapshot, Match: match, Next: 5, PendingSnapshot: 0, Inflights: NewInflights(256)},
			2,
		},
	}
	for i, tt := range tests {
		tt.p.BecomeProbe()
		if tt.p.State != StateProbe {
			t.Errorf("#%d: state = %s, want %s", i, tt.p.State, StateProbe)
		}
		if tt.p.Match != match {
			t.Errorf("#%d: match = %d, want %d", i, tt.p.Match, match)
		}
		if tt.p.Next != tt.wnext {
			t.Errorf("#%d: next = %d, want %d", i, tt.p.Next, tt.wnext)
		}
	}
}

func TestProgressBecomeReplicate(t *testing.T) {
	p := &Progress{State: StateProbe, Match: 1, Next: 5, Inflights: NewInflights(256)}
	p.BecomeReplicate()

	if p.State != StateReplicate {
		t.Errorf("state = %s, want %s", p.State, StateReplicate)
	}
	if p.Match != 1 {
		t.Errorf("match = %d, want 1", p.Match)
	}
	if w := p.Match + 1; p.Next != w {
		t.Errorf("next = %d, want %d", p.Next, w)
	}
}

func TestProgressBecomeSnapshot(t *testing.T) {
	p := &Progress{State: StateProbe, Match: 1, Next: 5, Inflights: NewInflights(256)}
	p.BecomeSnapshot(10)

	if p.State != StateSnapshot {
		t.Errorf("state = %s, want %s", p.State, StateSnapshot)
	}
	if p.Match != 1 {
		t.Errorf("match = %d, want 1", p.Match)
	}
	if p.PendingSnapshot != 10 {
		t.Errorf("pendingSnapshot = %d, want 10", p.PendingSnapshot)
	}
}

func TestProgressUpdate(t *testing.T) {
	prevM, prevN := uint64(3), uint64(5)
	tests := []struct {
		update uint64

		wm  uint64
		wn  uint64
		wok bool
	}{
		{prevM - 1, prevM, prevN, false},        // do not decrease match, next
		{prevM, prevM, prevN, false},            // do not decrease next
		{prevM + 1, prevM + 1, prevN, true},     // increase match, do not decrease next
		{prevM + 2, prevM + 2, prevN + 1, true}, // increase match, next
	}
	for i, tt := range tests {
		p := &Progress{
			Match: prevM,
			Next:  prevN,
		}
		ok := p.MaybeUpdate(tt.update)
		if ok != tt.wok {
			t.Errorf("#%d: ok= %v, want %v", i, ok, tt.wok)
		}
		if p.Match != tt.wm {
			t.Errorf("#%d: match= %d, want %d", i, p.Match, tt.wm)
		}
		if p.Next != tt.wn {
			t.Errorf("#%d: next= %d, want %d", i, p.Next, tt.wn)
		}
	}
}

func TestProgressMaybeDecr(t *testing.T) {
	tests := []struct {
		state    StateType
		m        uint64
		n        uint64
		rejected uint64
		last     uint64

		w  bool
		wn uint64
	}{
		{
			// state replicate and rejected is not greater than match
			StateReplicate, 5, 10, 5, 5, false, 10,
		},
		{
			// state replicate and rejected is not greater than match
			StateReplicate, 5, 10, 4, 4, false, 10,
		},
		{
			// state replicate and rejected is greater than match
			// directly decrease to match+1
			StateReplicate, 5, 10, 9, 9, true, 6,
		},
		{
			// next-1 != rejected is always false
			StateProbe, 0, 0, 0, 0, false, 0,
		},
		{
			// next-1 != rejected is always false
			StateProbe, 0, 10, 5, 5, false, 10,
		},
		{
			// next>1 = decremented by 1
			StateProbe, 0, 10, 9, 9, true, 9,
		},
		{
			// next>1 = decremented by 1
			StateProbe, 0, 2, 1, 1, true, 1,
		},
		{
			// next<=1 = reset to 1
			StateProbe, 0, 1, 0, 0, true, 1,
		},
		{
			// decrease to min(rejected, last+1)
			StateProbe, 0, 10, 9, 2, true, 3,
		},
		{
			// rejected < 1, reset to 1
			StateProbe, 0, 10, 9, 0, true, 1,
		},
	}
	for i, tt := range tests {
		p := &Progress{
			State: tt.state,
			Match: tt.m,
			Next:  tt.n,
		}
		if g := p.MaybeDecrTo(tt.rejected, tt.last); g != tt.w {
			t.Errorf("#%d: maybeDecrTo= %t, want %t", i, g, tt.w)
		}
		if gm := p.Match; gm != tt.m {
			t.Errorf("#%d: match= %d, want %d", i, gm, tt.m)
		}
		if gn := p.Next; gn != tt.wn {
			t.Errorf("#%d: next= %d, want %d", i, gn, tt.wn)
		}
	}
}