// Copyright 2018 The dexon-consensus-core Authors
// This file is part of the dexon-consensus-core library.
//
// The dexon-consensus-core library is free software: you can redistribute it
// and/or modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// The dexon-consensus-core library is distributed in the hope that it will be
// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
// General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the dexon-consensus-core library. If not, see
// <http://www.gnu.org/licenses/>.

package core

import (
	"testing"
	"time"

	"github.com/stretchr/testify/suite"

	"github.com/dexon-foundation/dexon-consensus-core/common"
	"github.com/dexon-foundation/dexon-consensus-core/core/types"
)

type slowApp struct {
	sleep                time.Duration
	blockConfirmed       map[common.Hash]struct{}
	stronglyAcked        map[common.Hash]struct{}
	totalOrderingDeliver map[common.Hash]struct{}
	deliverBlock         map[common.Hash]struct{}
	witnessAck           map[common.Hash]struct{}
}

func newSlowApp(sleep time.Duration) *slowApp {
	return &slowApp{
		sleep:                sleep,
		blockConfirmed:       make(map[common.Hash]struct{}),
		stronglyAcked:        make(map[common.Hash]struct{}),
		totalOrderingDeliver: make(map[common.Hash]struct{}),
		deliverBlock:         make(map[common.Hash]struct{}),
		witnessAck:           make(map[common.Hash]struct{}),
	}
}

func (app *slowApp) PreparePayload(_ types.Position) []byte {
	return []byte{}
}

func (app *slowApp) VerifyPayloads(_ []byte) bool {
	return true
}

func (app *slowApp) BlockConfirmed(block *types.Block) {
	time.Sleep(app.sleep)
	app.blockConfirmed[block.Hash] = struct{}{}
}

func (app *slowApp) StronglyAcked(blockHash common.Hash) {
	time.Sleep(app.sleep)
	app.stronglyAcked[blockHash] = struct{}{}
}

func (app *slowApp) TotalOrderingDeliver(blockHashes common.Hashes, early bool) {
	time.Sleep(app.sleep)
	for _, hash := range blockHashes {
		app.totalOrderingDeliver[hash] = struct{}{}
	}
}

func (app *slowApp) DeliverBlock(blockHash common.Hash, timestamp time.Time) {
	time.Sleep(app.sleep)
	app.deliverBlock[blockHash] = struct{}{}
}

func (app *slowApp) WitnessAckDeliver(witnessAck *types.WitnessAck) {
	time.Sleep(app.sleep)
	app.witnessAck[witnessAck.Hash] = struct{}{}
}

type NonBlockingAppTestSuite struct {
	suite.Suite
}

func (s *NonBlockingAppTestSuite) TestNonBlockingApplication() {
	sleep := 50 * time.Millisecond
	app := newSlowApp(sleep)
	nbapp := newNonBlockingApplication(app)
	hashes := make(common.Hashes, 10)
	for idx := range hashes {
		hashes[idx] = common.NewRandomHash()
	}
	now := time.Now().UTC()
	shouldFinish := now.Add(100 * time.Millisecond)

	// Start doing some 'heavy' job.
	for _, hash := range hashes {
		nbapp.BlockConfirmed(&types.Block{Hash: hash})
		nbapp.StronglyAcked(hash)
		nbapp.DeliverBlock(hash, time.Now().UTC())
		nbapp.WitnessAckDeliver(&types.WitnessAck{Hash: hash})
	}
	nbapp.TotalOrderingDeliver(hashes, true)

	// nonBlockingApplication should be non-blocking.
	s.True(shouldFinish.After(time.Now().UTC()))

	nbapp.wait()
	for _, hash := range hashes {
		s.Contains(app.blockConfirmed, hash)
		s.Contains(app.stronglyAcked, hash)
		s.Contains(app.totalOrderingDeliver, hash)
		s.Contains(app.deliverBlock, hash)
		s.Contains(app.witnessAck, hash)
	}
}

func TestNonBlockingApplication(t *testing.T) {
	suite.Run(t, new(NonBlockingAppTestSuite))
}