package common_test

import (
	"context"
	"fmt"
	"io/ioutil"
	"log"
	"math/big"
	"os"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/core/types"
	. "github.com/onsi/ginkgo"
	. "github.com/onsi/gomega"

	vulcCommon "github.com/vulcanize/vulcanizedb/pkg/geth/converters/common"
	"github.com/vulcanize/vulcanizedb/pkg/geth/converters/rpc"
)

type FakeGethClient struct {
	receipts map[string]*types.Receipt
	err      error
}

type TransActionReceiptError struct{}

func (tarErr TransActionReceiptError) Error() string {
	return fmt.Sprintf("transaction receipt error")
}

type TransactionSenderError struct{}

func (tasErr TransactionSenderError) Error() string {
	return fmt.Sprintf("transaction sender error")
}

func NewFakeClient(err error) *FakeGethClient {
	return &FakeGethClient{
		receipts: make(map[string]*types.Receipt),
		err:      err,
	}
}

func (client *FakeGethClient) AddReceipts(receipts []*types.Receipt) {
	for _, receipt := range receipts {
		client.receipts[receipt.TxHash.Hex()] = receipt
	}
}

func (client *FakeGethClient) TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error) {
	if err, ok := client.err.(TransActionReceiptError); ok {
		return &types.Receipt{}, err
	}
	if gasUsed, ok := client.receipts[txHash.Hex()]; ok {
		return gasUsed, nil
	}
	return &types.Receipt{GasUsed: uint64(0)}, nil
}

func (client *FakeGethClient) TransactionSender(ctx context.Context, tx *types.Transaction, block common.Hash, index uint) (common.Address, error) {
	if err, ok := client.err.(TransactionSenderError); ok {
		return common.Address{}, err
	}
	return common.HexToAddress("0x123"), nil
}

var _ = Describe("Conversion of GethBlock to core.Block", func() {

	It("converts basic Block metadata", func() {
		difficulty := big.NewInt(1)
		gasLimit := uint64(100000)
		gasUsed := uint64(100000)
		miner := common.HexToAddress("0x0000000000000000000000000000000000000123")
		extraData, _ := hexutil.Decode("0xe4b883e5bda9e7a59ee4bb99e9b1bc")
		nonce := types.BlockNonce{10}
		number := int64(1)
		time := int64(140000000)

		header := types.Header{
			Difficulty: difficulty,
			GasLimit:   uint64(gasLimit),
			GasUsed:    uint64(gasUsed),
			Extra:      extraData,
			Coinbase:   miner,
			Nonce:      nonce,
			Number:     big.NewInt(number),
			ParentHash: common.Hash{64},
			Time:       big.NewInt(time),
			UncleHash:  common.Hash{128},
		}
		block := types.NewBlock(&header, []*types.Transaction{}, []*types.Header{}, []*types.Receipt{})
		client := &FakeGethClient{}
		transactionConverter := rpc.NewRpcTransactionConverter(client)
		blockConverter := vulcCommon.NewBlockConverter(transactionConverter)

		coreBlock, err := blockConverter.ToCoreBlock(block)

		Expect(err).ToNot(HaveOccurred())
		Expect(coreBlock.Difficulty).To(Equal(difficulty.Int64()))
		Expect(coreBlock.GasLimit).To(Equal(gasLimit))
		Expect(coreBlock.Miner).To(Equal(miner.Hex()))
		Expect(coreBlock.GasUsed).To(Equal(gasUsed))
		Expect(coreBlock.Hash).To(Equal(block.Hash().Hex()))
		Expect(coreBlock.Nonce).To(Equal(hexutil.Encode(header.Nonce[:])))
		Expect(coreBlock.Number).To(Equal(number))
		Expect(coreBlock.ParentHash).To(Equal(block.ParentHash().Hex()))
		Expect(coreBlock.ExtraData).To(Equal(hexutil.Encode(block.Extra())))
		Expect(coreBlock.Size).To(Equal(block.Size().String()))
		Expect(coreBlock.Time).To(Equal(time))
		Expect(coreBlock.UncleHash).To(Equal(block.UncleHash().Hex()))
		Expect(coreBlock.IsFinal).To(BeFalse())
	})

	Describe("The block and uncle rewards calculations", func() {
		It("calculates block rewards for a block", func() {
			transaction := types.NewTransaction(
				uint64(226823),
				common.HexToAddress("0x108fedb097c1dcfed441480170144d8e19bb217f"),
				big.NewInt(1080900090000000000),
				uint64(90000),
				big.NewInt(50000000000),
				[]byte{},
			)
			transactions := []*types.Transaction{transaction}

			txHash := transaction.Hash()
			receipt := types.Receipt{
				TxHash:            txHash,
				GasUsed:           uint64(21000),
				CumulativeGasUsed: uint64(21000),
			}
			receipts := []*types.Receipt{&receipt}

			client := NewFakeClient(nil)
			client.AddReceipts(receipts)

			number := int64(1071819)
			header := types.Header{
				Number: big.NewInt(number),
			}
			uncles := []*types.Header{{Number: big.NewInt(1071817)}, {Number: big.NewInt(1071818)}}
			block := types.NewBlock(&header, transactions, uncles, []*types.Receipt{&receipt})
			transactionConverter := rpc.NewRpcTransactionConverter(client)
			blockConverter := vulcCommon.NewBlockConverter(transactionConverter)

			coreBlock, err := blockConverter.ToCoreBlock(block)

			Expect(err).ToNot(HaveOccurred())
			Expect(vulcCommon.CalcBlockReward(coreBlock, block.Uncles())).To(Equal(5.31355))
		})

		It("calculates the uncles reward for a block", func() {
			transaction := types.NewTransaction(
				uint64(226823),
				common.HexToAddress("0x108fedb097c1dcfed441480170144d8e19bb217f"),
				big.NewInt(1080900090000000000),
				uint64(90000),
				big.NewInt(50000000000),
				[]byte{})
			transactions := []*types.Transaction{transaction}

			receipt := types.Receipt{
				TxHash:            transaction.Hash(),
				GasUsed:           uint64(21000),
				CumulativeGasUsed: uint64(21000),
			}
			receipts := []*types.Receipt{&receipt}

			header := types.Header{
				Number: big.NewInt(int64(1071819)),
			}
			uncles := []*types.Header{
				{Number: big.NewInt(1071816)},
				{Number: big.NewInt(1071817)},
			}
			block := types.NewBlock(&header, transactions, uncles, receipts)

			client := NewFakeClient(nil)
			client.AddReceipts(receipts)
			transactionConverter := rpc.NewRpcTransactionConverter(client)
			blockConverter := vulcCommon.NewBlockConverter(transactionConverter)

			coreBlock, err := blockConverter.ToCoreBlock(block)

			Expect(err).ToNot(HaveOccurred())
			Expect(vulcCommon.CalcUnclesReward(coreBlock, block.Uncles())).To(Equal(6.875))
		})

		It("decreases the static block reward from 5 to 3 for blocks after block 4,269,999", func() {
			transactionOne := types.NewTransaction(
				uint64(8072),
				common.HexToAddress("0xebd17720aeb7ac5186c5dfa7bafeb0bb14c02551 "),
				big.NewInt(0),
				uint64(500000),
				big.NewInt(42000000000),
				[]byte{},
			)

			transactionTwo := types.NewTransaction(uint64(8071),
				common.HexToAddress("0x3cdab63d764c8c5048ed5e8f0a4e95534ba7e1ea"),
				big.NewInt(0),
				uint64(500000),
				big.NewInt(42000000000),
				[]byte{})

			transactions := []*types.Transaction{transactionOne, transactionTwo}

			receiptOne := types.Receipt{
				TxHash:            transactionOne.Hash(),
				GasUsed:           uint64(297508),
				CumulativeGasUsed: uint64(0),
			}
			receiptTwo := types.Receipt{
				TxHash:            transactionTwo.Hash(),
				GasUsed:           uint64(297508),
				CumulativeGasUsed: uint64(0),
			}
			receipts := []*types.Receipt{&receiptOne, &receiptTwo}

			number := int64(4370055)
			header := types.Header{
				Number: big.NewInt(number),
			}
			var uncles []*types.Header
			block := types.NewBlock(&header, transactions, uncles, receipts)

			client := NewFakeClient(nil)
			client.AddReceipts(receipts)
			transactionConverter := rpc.NewRpcTransactionConverter(client)
			blockConverter := vulcCommon.NewBlockConverter(transactionConverter)

			coreBlock, err := blockConverter.ToCoreBlock(block)

			Expect(err).ToNot(HaveOccurred())
			Expect(vulcCommon.CalcBlockReward(coreBlock, block.Uncles())).To(Equal(3.024990672))
		})
	})

	Describe("the converted transactions", func() {
		It("is empty", func() {
			header := types.Header{}
			block := types.NewBlock(&header, []*types.Transaction{}, []*types.Header{}, []*types.Receipt{})
			client := &FakeGethClient{}
			transactionConverter := rpc.NewRpcTransactionConverter(client)
			blockConverter := vulcCommon.NewBlockConverter(transactionConverter)

			coreBlock, err := blockConverter.ToCoreBlock(block)

			Expect(err).ToNot(HaveOccurred())
			Expect(len(coreBlock.Transactions)).To(Equal(0))
		})

		It("converts a single transaction", func() {
			gethTransaction := types.NewTransaction(
				uint64(10000), common.Address{1},
				big.NewInt(10),
				uint64(5000),
				big.NewInt(3),
				hexutil.MustDecode("0xf7d8c8830000000000000000000000000000000000000000000000000000000000037788000000000000000000000000000000000000000000000000000000000003bd14"),
			)

			gethReceipt := &types.Receipt{
				Bloom:             types.BytesToBloom(hexutil.MustDecode("0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000")),
				ContractAddress:   common.HexToAddress("x123"),
				CumulativeGasUsed: uint64(7996119),
				GasUsed:           uint64(21000),
				Logs:              []*types.Log{},
				Status:            uint(1),
				TxHash:            gethTransaction.Hash(),
			}

			client := NewFakeClient(nil)
			client.AddReceipts([]*types.Receipt{gethReceipt})

			header := types.Header{}
			block := types.NewBlock(
				&header,
				[]*types.Transaction{gethTransaction},
				[]*types.Header{},
				[]*types.Receipt{gethReceipt},
			)
			transactionConverter := rpc.NewRpcTransactionConverter(client)
			blockConverter := vulcCommon.NewBlockConverter(transactionConverter)

			coreBlock, err := blockConverter.ToCoreBlock(block)

			Expect(err).ToNot(HaveOccurred())
			Expect(len(coreBlock.Transactions)).To(Equal(1))
			coreTransaction := coreBlock.Transactions[0]
			Expect(coreTransaction.Data).To(Equal("0xf7d8c8830000000000000000000000000000000000000000000000000000000000037788000000000000000000000000000000000000000000000000000000000003bd14"))
			Expect(coreTransaction.To).To(Equal(gethTransaction.To().Hex()))
			Expect(coreTransaction.From).To(Equal("0x0000000000000000000000000000000000000123"))
			Expect(coreTransaction.GasLimit).To(Equal(gethTransaction.Gas()))
			Expect(coreTransaction.GasPrice).To(Equal(gethTransaction.GasPrice().Int64()))
			Expect(coreTransaction.Value).To(Equal(gethTransaction.Value().String()))
			Expect(coreTransaction.Nonce).To(Equal(gethTransaction.Nonce()))

			coreReceipt := coreTransaction.Receipt
			expectedReceipt := vulcCommon.ToCoreReceipt(gethReceipt)
			Expect(coreReceipt).To(Equal(expectedReceipt))
		})

		It("has an empty 'To' field when transaction creates a new contract", func() {
			gethTransaction := types.NewContractCreation(
				uint64(10000),
				big.NewInt(10),
				uint64(5000),
				big.NewInt(3),
				[]byte("1234"),
			)

			gethReceipt := &types.Receipt{
				CumulativeGasUsed: uint64(1),
				GasUsed:           uint64(1),
				TxHash:            gethTransaction.Hash(),
				ContractAddress:   common.HexToAddress("0x1023342345"),
			}

			client := NewFakeClient(nil)
			client.AddReceipts([]*types.Receipt{gethReceipt})

			block := types.NewBlock(
				&types.Header{},
				[]*types.Transaction{gethTransaction},
				[]*types.Header{},
				[]*types.Receipt{gethReceipt},
			)
			transactionConverter := rpc.NewRpcTransactionConverter(client)
			blockConverter := vulcCommon.NewBlockConverter(transactionConverter)

			coreBlock, err := blockConverter.ToCoreBlock(block)

			Expect(err).ToNot(HaveOccurred())
			coreTransaction := coreBlock.Transactions[0]
			Expect(coreTransaction.To).To(Equal(""))

			coreReceipt := coreTransaction.Receipt
			expectedReceipt := vulcCommon.ToCoreReceipt(gethReceipt)
			Expect(coreReceipt).To(Equal(expectedReceipt))
		})
	})

	Describe("transaction error handling", func() {
		var gethTransaction *types.Transaction
		var gethReceipt *types.Receipt
		var header *types.Header
		var block *types.Block

		BeforeEach(func() {
			log.SetOutput(ioutil.Discard)
			gethTransaction = types.NewTransaction(
				uint64(0),
				common.Address{},
				big.NewInt(0),
				uint64(0),
				big.NewInt(0),
				[]byte{},
			)
			gethReceipt = &types.Receipt{}
			header = &types.Header{}
			block = types.NewBlock(
				header,
				[]*types.Transaction{gethTransaction},
				[]*types.Header{},
				[]*types.Receipt{gethReceipt},
			)

		})

		AfterEach(func() {
			defer log.SetOutput(os.Stdout)
		})

		It("returns an error when transaction sender call fails", func() {
			client := NewFakeClient(TransactionSenderError{})
			client.AddReceipts([]*types.Receipt{})
			transactionConverter := rpc.NewRpcTransactionConverter(client)
			blockConverter := vulcCommon.NewBlockConverter(transactionConverter)

			_, err := blockConverter.ToCoreBlock(block)

			Expect(err).To(Equal(TransactionSenderError{}))
		})

		It("returns an error when transaction receipt call fails", func() {
			client := NewFakeClient(TransActionReceiptError{})
			client.AddReceipts([]*types.Receipt{})
			transactionConverter := rpc.NewRpcTransactionConverter(client)
			blockConverter := vulcCommon.NewBlockConverter(transactionConverter)

			_, err := blockConverter.ToCoreBlock(block)

			Expect(err).To(Equal(TransActionReceiptError{}))
		})
	})

})