// Copyright 2019 Vulcanize
//
// 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 fetcher_test

import (
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/rpc"
	"github.com/ethereum/go-ethereum/statediff"
	. "github.com/onsi/ginkgo"
	. "github.com/onsi/gomega"
	"github.com/vulcanize/vulcanizedb/libraries/shared/fetcher"
	"github.com/vulcanize/vulcanizedb/libraries/shared/storage/utils"
	"github.com/vulcanize/vulcanizedb/libraries/shared/test_data"
	"github.com/vulcanize/vulcanizedb/pkg/fakes"
)

type MockStoragediffStreamer struct {
	subscribeError error
	PassedPayloadChan chan statediff.Payload
	streamPayloads []statediff.Payload
}

func (streamer *MockStoragediffStreamer) Stream(statediffPayloadChan chan statediff.Payload) (*rpc.ClientSubscription, error) {
	clientSubscription := rpc.ClientSubscription{}
	streamer.PassedPayloadChan = statediffPayloadChan

	go func() {
		for _, payload := range streamer.streamPayloads {
			streamer.PassedPayloadChan <- payload
		}
	}()

	return &clientSubscription, streamer.subscribeError
}

func (streamer *MockStoragediffStreamer) SetSubscribeError(err error) {
	streamer.subscribeError = err
}

func (streamer *MockStoragediffStreamer) SetPayloads(payloads []statediff.Payload) {
	streamer.streamPayloads = payloads
}

var _ = Describe("Geth RPC Storage Fetcher", func() {
	var streamer MockStoragediffStreamer
	var statediffPayloadChan chan statediff.Payload
	var statediffFetcher fetcher.GethRpcStorageFetcher
	var storagediffRowChan chan utils.StorageDiffRow
	var errorChan chan error


	BeforeEach(func() {
		streamer = MockStoragediffStreamer{}
		statediffPayloadChan = make(chan statediff.Payload, 1)
		statediffFetcher = fetcher.NewGethRpcStorageFetcher(&streamer, statediffPayloadChan)
		storagediffRowChan = make(chan utils.StorageDiffRow)
		errorChan = make(chan error)
	})

	It("adds errors to error channel if the RPC subscription fails ", func(done Done) {
		streamer.SetSubscribeError(fakes.FakeError)

		go statediffFetcher.FetchStorageDiffs(storagediffRowChan, errorChan)

		Expect(<-errorChan).To(MatchError(fakes.FakeError))
		close(done)
	})

	It("streams StatediffPayloads from a Geth RPC subscription", func(done Done) {
		streamer.SetPayloads([]statediff.Payload{test_data.MockStatediffPayload})

		go statediffFetcher.FetchStorageDiffs(storagediffRowChan, errorChan)

		streamedPayload := <-statediffPayloadChan
		Expect(streamedPayload).To(Equal(test_data.MockStatediffPayload))
		Expect(streamer.PassedPayloadChan).To(Equal(statediffPayloadChan))
		close(done)
	})

	It("adds parsed statediff payloads to the rows channel", func(done Done) {
		streamer.SetPayloads([]statediff.Payload{test_data.MockStatediffPayload})

		go statediffFetcher.FetchStorageDiffs(storagediffRowChan, errorChan)

		height := test_data.BlockNumber
		intHeight := int(height.Int64())
		expectedStorageDiffRow := utils.StorageDiffRow{
			//this is not the contract address, but the keccak 256 of the address
			Contract:     common.BytesToAddress(test_data.ContractLeafKey[:]),
			BlockHash:    common.HexToHash("0xfa40fbe2d98d98b3363a778d52f2bcd29d6790b9b3f3cab2b167fd12d3550f73"),
			BlockHeight:  intHeight,
			StorageKey:   common.BytesToHash(test_data.StorageKey),
			StorageValue: common.BytesToHash(test_data.StorageValue),
		}
		anotherExpectedStorageDiffRow := utils.StorageDiffRow{
			//this is not the contract address, but the keccak 256 of the address
			Contract:     common.BytesToAddress(test_data.AnotherContractLeafKey[:]),
			BlockHash:    common.HexToHash("0xfa40fbe2d98d98b3363a778d52f2bcd29d6790b9b3f3cab2b167fd12d3550f73"),
			BlockHeight:  intHeight,
			StorageKey:   common.BytesToHash(test_data.StorageKey),
			StorageValue: common.BytesToHash(test_data.StorageValue),
		}
		Expect(<-storagediffRowChan).To(Equal(expectedStorageDiffRow))
		Expect(<-storagediffRowChan).To(Equal(anotherExpectedStorageDiffRow))

		close(done)
	})

	It("adds errors to error channel if parsing the diff fails", func(done Done) {
		badStatediffPayload := statediff.Payload{}
		streamer.SetPayloads([]statediff.Payload{badStatediffPayload})

		go statediffFetcher.FetchStorageDiffs(storagediffRowChan, errorChan)

		Expect(<-errorChan).To(MatchError("EOF"))

		close(done)
	})
})