// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum 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 go-ethereum 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 go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package ethclient

import (
	"context"
	"errors"
	"fmt"
	"math/big"
	"reflect"
	"testing"
	"time"

	"github.com/ethereum/go-ethereum"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/consensus/ethash"
	"github.com/ethereum/go-ethereum/core"
	"github.com/ethereum/go-ethereum/core/rawdb"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/ethereum/go-ethereum/eth"
	"github.com/ethereum/go-ethereum/node"
	"github.com/ethereum/go-ethereum/params"
)

// Verify that Client implements the ethereum interfaces.
var (
	_ = ethereum.ChainReader(&Client{})
	_ = ethereum.TransactionReader(&Client{})
	_ = ethereum.ChainStateReader(&Client{})
	_ = ethereum.ChainSyncReader(&Client{})
	_ = ethereum.ContractCaller(&Client{})
	_ = ethereum.GasEstimator(&Client{})
	_ = ethereum.GasPricer(&Client{})
	_ = ethereum.LogFilterer(&Client{})
	_ = ethereum.PendingStateReader(&Client{})
	// _ = ethereum.PendingStateEventer(&Client{})
	_ = ethereum.PendingContractCaller(&Client{})
)

func TestToFilterArg(t *testing.T) {
	blockHashErr := fmt.Errorf("cannot specify both BlockHash and FromBlock/ToBlock")
	addresses := []common.Address{
		common.HexToAddress("0xD36722ADeC3EdCB29c8e7b5a47f352D701393462"),
	}
	blockHash := common.HexToHash(
		"0xeb94bb7d78b73657a9d7a99792413f50c0a45c51fc62bdcb08a53f18e9a2b4eb",
	)

	for _, testCase := range []struct {
		name   string
		input  ethereum.FilterQuery
		output interface{}
		err    error
	}{
		{
			"without BlockHash",
			ethereum.FilterQuery{
				Addresses: addresses,
				FromBlock: big.NewInt(1),
				ToBlock:   big.NewInt(2),
				Topics:    [][]common.Hash{},
			},
			map[string]interface{}{
				"address":   addresses,
				"fromBlock": "0x1",
				"toBlock":   "0x2",
				"topics":    [][]common.Hash{},
			},
			nil,
		},
		{
			"with nil fromBlock and nil toBlock",
			ethereum.FilterQuery{
				Addresses: addresses,
				Topics:    [][]common.Hash{},
			},
			map[string]interface{}{
				"address":   addresses,
				"fromBlock": "0x0",
				"toBlock":   "latest",
				"topics":    [][]common.Hash{},
			},
			nil,
		},
		{
			"with negative fromBlock and negative toBlock",
			ethereum.FilterQuery{
				Addresses: addresses,
				FromBlock: big.NewInt(-1),
				ToBlock:   big.NewInt(-1),
				Topics:    [][]common.Hash{},
			},
			map[string]interface{}{
				"address":   addresses,
				"fromBlock": "pending",
				"toBlock":   "pending",
				"topics":    [][]common.Hash{},
			},
			nil,
		},
		{
			"with blockhash",
			ethereum.FilterQuery{
				Addresses: addresses,
				BlockHash: &blockHash,
				Topics:    [][]common.Hash{},
			},
			map[string]interface{}{
				"address":   addresses,
				"blockHash": blockHash,
				"topics":    [][]common.Hash{},
			},
			nil,
		},
		{
			"with blockhash and from block",
			ethereum.FilterQuery{
				Addresses: addresses,
				BlockHash: &blockHash,
				FromBlock: big.NewInt(1),
				Topics:    [][]common.Hash{},
			},
			nil,
			blockHashErr,
		},
		{
			"with blockhash and to block",
			ethereum.FilterQuery{
				Addresses: addresses,
				BlockHash: &blockHash,
				ToBlock:   big.NewInt(1),
				Topics:    [][]common.Hash{},
			},
			nil,
			blockHashErr,
		},
		{
			"with blockhash and both from / to block",
			ethereum.FilterQuery{
				Addresses: addresses,
				BlockHash: &blockHash,
				FromBlock: big.NewInt(1),
				ToBlock:   big.NewInt(2),
				Topics:    [][]common.Hash{},
			},
			nil,
			blockHashErr,
		},
	} {
		t.Run(testCase.name, func(t *testing.T) {
			output, err := toFilterArg(testCase.input)
			if (testCase.err == nil) != (err == nil) {
				t.Fatalf("expected error %v but got %v", testCase.err, err)
			}
			if testCase.err != nil {
				if testCase.err.Error() != err.Error() {
					t.Fatalf("expected error %v but got %v", testCase.err, err)
				}
			} else if !reflect.DeepEqual(testCase.output, output) {
				t.Fatalf("expected filter arg %v but got %v", testCase.output, output)
			}
		})
	}
}

var (
	testKey, _  = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
	testAddr    = crypto.PubkeyToAddress(testKey.PublicKey)
	testBalance = big.NewInt(2e10)
)

func newTestBackend(t *testing.T) (*node.Node, []*types.Block) {
	// Generate test chain.
	genesis, blocks := generateTestChain()

	// Start Ethereum service.
	var ethservice *eth.Ethereum
	n, err := node.New(&node.Config{})
	n.Register(func(ctx *node.ServiceContext) (node.Service, error) {
		config := &eth.Config{Genesis: genesis}
		config.Ethash.PowMode = ethash.ModeFake
		ethservice, err = eth.New(ctx, config)
		return ethservice, err
	})

	// Import the test chain.
	if err := n.Start(); err != nil {
		t.Fatalf("can't start test node: %v", err)
	}
	if _, err := ethservice.BlockChain().InsertChain(blocks[1:]); err != nil {
		t.Fatalf("can't import test blocks: %v", err)
	}
	return n, blocks
}

func generateTestChain() (*core.Genesis, []*types.Block) {
	db := rawdb.NewMemoryDatabase()
	config := params.AllEthashProtocolChanges
	genesis := &core.Genesis{
		Config:    config,
		Alloc:     core.GenesisAlloc{testAddr: {Balance: testBalance}},
		ExtraData: []byte("test genesis"),
		Timestamp: 9000,
	}
	generate := func(i int, g *core.BlockGen) {
		g.OffsetTime(5)
		g.SetExtra([]byte("test"))
	}
	gblock := genesis.ToBlock(db)
	engine := ethash.NewFaker()
	blocks, _ := core.GenerateChain(config, gblock, engine, db, 1, generate)
	blocks = append([]*types.Block{gblock}, blocks...)
	return genesis, blocks
}

func TestHeader(t *testing.T) {
	backend, chain := newTestBackend(t)
	client, _ := backend.Attach()
	defer backend.Stop()
	defer client.Close()

	tests := map[string]struct {
		block   *big.Int
		want    *types.Header
		wantErr error
	}{
		"genesis": {
			block: big.NewInt(0),
			want:  chain[0].Header(),
		},
		"first_block": {
			block: big.NewInt(1),
			want:  chain[1].Header(),
		},
		"future_block": {
			block: big.NewInt(1000000000),
			want:  nil,
		},
	}
	for name, tt := range tests {
		t.Run(name, func(t *testing.T) {
			ec := NewClient(client)
			ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
			defer cancel()

			got, err := ec.HeaderByNumber(ctx, tt.block)
			if tt.wantErr != nil && (err == nil || err.Error() != tt.wantErr.Error()) {
				t.Fatalf("HeaderByNumber(%v) error = %q, want %q", tt.block, err, tt.wantErr)
			}
			if got != nil && got.Number.Sign() == 0 {
				got.Number = big.NewInt(0) // hack to make DeepEqual work
			}
			if !reflect.DeepEqual(got, tt.want) {
				t.Fatalf("HeaderByNumber(%v)\n   = %v\nwant %v", tt.block, got, tt.want)
			}
		})
	}
}

func TestBalanceAt(t *testing.T) {
	backend, _ := newTestBackend(t)
	client, _ := backend.Attach()
	defer backend.Stop()
	defer client.Close()

	tests := map[string]struct {
		account common.Address
		block   *big.Int
		want    *big.Int
		wantErr error
	}{
		"valid_account": {
			account: testAddr,
			block:   big.NewInt(1),
			want:    testBalance,
		},
		"non_existent_account": {
			account: common.Address{1},
			block:   big.NewInt(1),
			want:    big.NewInt(0),
		},
		"future_block": {
			account: testAddr,
			block:   big.NewInt(1000000000),
			want:    big.NewInt(0),
			wantErr: errors.New("header not found"),
		},
	}
	for name, tt := range tests {
		t.Run(name, func(t *testing.T) {
			ec := NewClient(client)
			ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
			defer cancel()

			got, err := ec.BalanceAt(ctx, tt.account, tt.block)
			if tt.wantErr != nil && (err == nil || err.Error() != tt.wantErr.Error()) {
				t.Fatalf("BalanceAt(%x, %v) error = %q, want %q", tt.account, tt.block, err, tt.wantErr)
			}
			if got.Cmp(tt.want) != 0 {
				t.Fatalf("BalanceAt(%x, %v) = %v, want %v", tt.account, tt.block, got, tt.want)
			}
		})
	}
}

func TestTransactionInBlockInterrupted(t *testing.T) {
	backend, _ := newTestBackend(t)
	client, _ := backend.Attach()
	defer backend.Stop()
	defer client.Close()

	ec := NewClient(client)
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	tx, err := ec.TransactionInBlock(ctx, common.Hash{1}, 1)
	if tx != nil {
		t.Fatal("transaction should be nil")
	}
	if err == nil {
		t.Fatal("error should not be nil")
	}
}

func TestChainID(t *testing.T) {
	backend, _ := newTestBackend(t)
	client, _ := backend.Attach()
	defer backend.Stop()
	defer client.Close()
	ec := NewClient(client)

	id, err := ec.ChainID(context.Background())
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	if id == nil || id.Cmp(params.AllEthashProtocolChanges.ChainID) != 0 {
		t.Fatalf("ChainID returned wrong number: %+v", id)
	}
}