// Copyright 2015 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 tests

import (
	"bytes"
	"fmt"
	"io"
	"math/big"
	"strconv"
	"testing"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/math"
	"github.com/ethereum/go-ethereum/core/state"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/core/vm"
	"github.com/ethereum/go-ethereum/ethdb"
	"github.com/ethereum/go-ethereum/log"
	"github.com/ethereum/go-ethereum/params"
)

func RunVmTestWithReader(r io.Reader, skipTests []string) error {
	tests := make(map[string]VmTest)
	err := readJson(r, &tests)
	if err != nil {
		return err
	}

	if err != nil {
		return err
	}

	if err := runVmTests(tests, skipTests); err != nil {
		return err
	}

	return nil
}

type bconf struct {
	name    string
	precomp bool
	jit     bool
}

func BenchVmTest(p string, conf bconf, b *testing.B) error {
	tests := make(map[string]VmTest)
	err := readJsonFile(p, &tests)
	if err != nil {
		return err
	}

	test, ok := tests[conf.name]
	if !ok {
		return fmt.Errorf("test not found: %s", conf.name)
	}

	env := make(map[string]string)
	env["currentCoinbase"] = test.Env.CurrentCoinbase
	env["currentDifficulty"] = test.Env.CurrentDifficulty
	env["currentGasLimit"] = test.Env.CurrentGasLimit
	env["currentNumber"] = test.Env.CurrentNumber
	env["previousHash"] = test.Env.PreviousHash
	if n, ok := test.Env.CurrentTimestamp.(float64); ok {
		env["currentTimestamp"] = strconv.Itoa(int(n))
	} else {
		env["currentTimestamp"] = test.Env.CurrentTimestamp.(string)
	}

	/*
		if conf.precomp {
			program := vm.NewProgram(test.code)
			err := vm.AttachProgram(program)
			if err != nil {
				return err
			}
		}
	*/

	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		benchVmTest(test, env, b)
	}

	return nil
}

func benchVmTest(test VmTest, env map[string]string, b *testing.B) {
	b.StopTimer()
	db, _ := ethdb.NewMemDatabase()
	statedb := makePreState(db, test.Pre)
	b.StartTimer()

	RunVm(statedb, env, test.Exec)
}

func RunVmTest(p string, skipTests []string) error {
	tests := make(map[string]VmTest)
	err := readJsonFile(p, &tests)
	if err != nil {
		return err
	}

	if err := runVmTests(tests, skipTests); err != nil {
		return err
	}

	return nil
}

func runVmTests(tests map[string]VmTest, skipTests []string) error {
	skipTest := make(map[string]bool, len(skipTests))
	for _, name := range skipTests {
		skipTest[name] = true
	}

	for name, test := range tests {
		if skipTest[name] /*|| name != "exp0"*/ {
			log.Info(fmt.Sprint("Skipping VM test", name))
			continue
		}

		if err := runVmTest(test); err != nil {
			return fmt.Errorf("%s %s", name, err.Error())
		}

		log.Info(fmt.Sprint("VM test passed: ", name))
		//fmt.Println(string(statedb.Dump()))
	}
	return nil
}

func runVmTest(test VmTest) error {
	db, _ := ethdb.NewMemDatabase()
	statedb := makePreState(db, test.Pre)

	// XXX Yeah, yeah...
	env := make(map[string]string)
	env["currentCoinbase"] = test.Env.CurrentCoinbase
	env["currentDifficulty"] = test.Env.CurrentDifficulty
	env["currentGasLimit"] = test.Env.CurrentGasLimit
	env["currentNumber"] = test.Env.CurrentNumber
	env["previousHash"] = test.Env.PreviousHash
	if n, ok := test.Env.CurrentTimestamp.(float64); ok {
		env["currentTimestamp"] = strconv.Itoa(int(n))
	} else {
		env["currentTimestamp"] = test.Env.CurrentTimestamp.(string)
	}

	var (
		ret  []byte
		gas  *big.Int
		err  error
		logs []*types.Log
	)

	ret, logs, gas, err = RunVm(statedb, env, test.Exec)

	// Compare expected and actual return
	rexp := common.FromHex(test.Out)
	if !bytes.Equal(rexp, ret) {
		return fmt.Errorf("return failed. Expected %x, got %x\n", rexp, ret)
	}

	// Check gas usage
	if len(test.Gas) == 0 && err == nil {
		return fmt.Errorf("gas unspecified, indicating an error. VM returned (incorrectly) successful")
	} else {
		gexp := math.MustParseBig256(test.Gas)
		if gexp.Cmp(gas) != 0 {
			return fmt.Errorf("gas failed. Expected %v, got %v\n", gexp, gas)
		}
	}

	// check post state
	for address, account := range test.Post {
		accountAddr := common.HexToAddress(address)
		if !statedb.Exist(accountAddr) {
			continue
		}
		for addr, value := range account.Storage {
			v := statedb.GetState(accountAddr, common.HexToHash(addr))
			vexp := common.HexToHash(value)
			if v != vexp {
				return fmt.Errorf("(%x: %s) storage failed. Expected %x, got %x (%v %v)\n", addr[:4], addr, vexp, v, vexp.Big(), v.Big())
			}
		}
	}

	// check logs
	if len(test.Logs) > 0 {
		lerr := checkLogs(test.Logs, logs)
		if lerr != nil {
			return lerr
		}
	}

	return nil
}

func RunVm(statedb *state.StateDB, env, exec map[string]string) ([]byte, []*types.Log, *big.Int, error) {
	chainConfig := &params.ChainConfig{
		HomesteadBlock: params.MainNetHomesteadBlock,
		DAOForkBlock:   params.MainNetDAOForkBlock,
		DAOForkSupport: true,
	}
	var (
		to    = common.HexToAddress(exec["address"])
		from  = common.HexToAddress(exec["caller"])
		data  = common.FromHex(exec["data"])
		gas   = math.MustParseBig256(exec["gas"])
		value = math.MustParseBig256(exec["value"])
	)
	caller := statedb.GetOrNewStateObject(from)
	vm.PrecompiledContracts = make(map[common.Address]vm.PrecompiledContract)

	environment, _ := NewEVMEnvironment(true, chainConfig, statedb, env, exec)
	ret, g, err := environment.Call(caller, to, data, gas.Uint64(), value)
	return ret, statedb.Logs(), new(big.Int).SetUint64(g), err
}
