package network

import (
	"testing"
	"time"

	"github.com/nspcc-dev/neo-go/internal/fakechain"
	"github.com/nspcc-dev/neo-go/pkg/core/block"
	"github.com/stretchr/testify/assert"
	"go.uber.org/zap/zaptest"
)

func TestBlockQueue(t *testing.T) {
	chain := fakechain.NewFakeChain()
	// notice, it's not yet running
	bq := newBlockQueue(0, chain, zaptest.NewLogger(t), nil)
	blocks := make([]*block.Block, 11)
	for i := 1; i < 11; i++ {
		blocks[i] = &block.Block{Header: block.Header{Index: uint32(i)}}
	}
	// not the ones expected currently
	for i := 3; i < 5; i++ {
		assert.NoError(t, bq.putBlock(blocks[i]))
	}
	last, capLeft := bq.lastQueued()
	assert.Equal(t, uint32(0), last)
	assert.Equal(t, blockCacheSize-2, capLeft)
	// nothing should be put into the blockchain
	assert.Equal(t, uint32(0), chain.BlockHeight())
	assert.Equal(t, 2, bq.length())
	// now added the expected ones (with duplicates)
	for i := 1; i < 5; i++ {
		assert.NoError(t, bq.putBlock(blocks[i]))
	}
	// but they're still not put into the blockchain, because bq isn't running
	last, capLeft = bq.lastQueued()
	assert.Equal(t, uint32(4), last)
	assert.Equal(t, blockCacheSize-4, capLeft)
	assert.Equal(t, uint32(0), chain.BlockHeight())
	assert.Equal(t, 4, bq.length())
	// block with too big index is dropped
	assert.NoError(t, bq.putBlock(&block.Block{Header: block.Header{Index: bq.chain.BlockHeight() + blockCacheSize + 1}}))
	assert.Equal(t, 4, bq.length())
	go bq.run()
	// run() is asynchronous, so we need some kind of timeout anyway and this is the simplest one
	assert.Eventually(t, func() bool { return chain.BlockHeight() == 4 }, 4*time.Second, 100*time.Millisecond)
	last, capLeft = bq.lastQueued()
	assert.Equal(t, uint32(4), last)
	assert.Equal(t, blockCacheSize, capLeft)
	assert.Equal(t, 0, bq.length())
	assert.Equal(t, uint32(4), chain.BlockHeight())
	// put some old blocks
	for i := 1; i < 5; i++ {
		assert.NoError(t, bq.putBlock(blocks[i]))
	}
	last, capLeft = bq.lastQueued()
	assert.Equal(t, uint32(4), last)
	assert.Equal(t, blockCacheSize, capLeft)
	assert.Equal(t, 0, bq.length())
	assert.Equal(t, uint32(4), chain.BlockHeight())
	// unexpected blocks with run() active
	assert.NoError(t, bq.putBlock(blocks[8]))
	assert.Equal(t, 1, bq.length())
	assert.Equal(t, uint32(4), chain.BlockHeight())
	assert.NoError(t, bq.putBlock(blocks[7]))
	assert.Equal(t, 2, bq.length())
	assert.Equal(t, uint32(4), chain.BlockHeight())
	// sparse put
	assert.NoError(t, bq.putBlock(blocks[10]))
	assert.Equal(t, 3, bq.length())
	assert.Equal(t, uint32(4), chain.BlockHeight())
	assert.NoError(t, bq.putBlock(blocks[6]))
	assert.NoError(t, bq.putBlock(blocks[5]))
	// run() is asynchronous, so we need some kind of timeout anyway and this is the simplest one
	assert.Eventually(t, func() bool { return chain.BlockHeight() == 8 }, 4*time.Second, 100*time.Millisecond)
	last, capLeft = bq.lastQueued()
	assert.Equal(t, uint32(8), last)
	assert.Equal(t, blockCacheSize-1, capLeft)
	assert.Equal(t, 1, bq.length())
	assert.Equal(t, uint32(8), chain.BlockHeight())
	bq.discard()
	assert.Equal(t, 0, bq.length())
}

// length wraps len access for tests to make them thread-safe.
func (bq *blockQueue) length() int {
	bq.queueLock.Lock()
	defer bq.queueLock.Unlock()
	return bq.len
}