// Copyright 2017 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.

package main

import (
	"bufio"
	"encoding/json"
	"fmt"
	"os"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/core/rawdb"
	"github.com/ethereum/go-ethereum/core/state"
	"github.com/ethereum/go-ethereum/core/vm"
	"github.com/ethereum/go-ethereum/eth/tracers/logger"
	"github.com/ethereum/go-ethereum/internal/flags"
	"github.com/ethereum/go-ethereum/tests"
	"github.com/urfave/cli/v2"
)

var (
	forkFlag = &cli.StringFlag{
		Name:     "statetest.fork",
		Usage:    "The hard-fork to run the test against",
		Category: flags.VMCategory,
	}
	idxFlag = &cli.IntFlag{
		Name:     "statetest.index",
		Usage:    "The index of the subtest to run",
		Category: flags.VMCategory,
		Value:    -1, // default to select all subtest indices
	}
	testNameFlag = &cli.StringFlag{
		Name:     "statetest.name",
		Usage:    "The name of the state test to run",
		Category: flags.VMCategory,
	}
)
var stateTestCommand = &cli.Command{
	Action:    stateTestCmd,
	Name:      "statetest",
	Usage:     "Executes the given state tests. Filenames can be fed via standard input (batch mode) or as an argument (one-off execution).",
	ArgsUsage: "<file>",
	Flags: []cli.Flag{
		forkFlag,
		idxFlag,
		testNameFlag,
	},
}

// StatetestResult contains the execution status after running a state test, any
// error that might have occurred and a dump of the final state if requested.
type StatetestResult struct {
	Name       string       `json:"name"`
	Pass       bool         `json:"pass"`
	Root       *common.Hash `json:"stateRoot,omitempty"`
	Fork       string       `json:"fork"`
	Error      string       `json:"error,omitempty"`
	State      *state.Dump  `json:"state,omitempty"`
	BenchStats *execStats   `json:"benchStats,omitempty"`
}

func stateTestCmd(ctx *cli.Context) error {
	// Configure the EVM logger
	config := &logger.Config{
		EnableMemory:     !ctx.Bool(DisableMemoryFlag.Name),
		DisableStack:     ctx.Bool(DisableStackFlag.Name),
		DisableStorage:   ctx.Bool(DisableStorageFlag.Name),
		EnableReturnData: !ctx.Bool(DisableReturnDataFlag.Name),
	}
	var cfg vm.Config
	switch {
	case ctx.Bool(MachineFlag.Name):
		cfg.Tracer = logger.NewJSONLogger(config, os.Stderr)

	case ctx.Bool(DebugFlag.Name):
		cfg.Tracer = logger.NewStructLogger(config).Hooks()
	}
	// Load the test content from the input file
	if len(ctx.Args().First()) != 0 {
		return runStateTest(ctx, ctx.Args().First(), cfg, ctx.Bool(DumpFlag.Name), ctx.Bool(BenchFlag.Name))
	}
	// Read filenames from stdin and execute back-to-back
	scanner := bufio.NewScanner(os.Stdin)
	for scanner.Scan() {
		fname := scanner.Text()
		if len(fname) == 0 {
			return nil
		}
		if err := runStateTest(ctx, fname, cfg, ctx.Bool(DumpFlag.Name), ctx.Bool(BenchFlag.Name)); err != nil {
			return err
		}
	}
	return nil
}

type stateTestCase struct {
	name string
	test tests.StateTest
	st   tests.StateSubtest
}

// collectMatchedSubtests returns test cases which match against provided filtering CLI parameters
func collectMatchedSubtests(ctx *cli.Context, testsByName map[string]tests.StateTest) []stateTestCase {
	var res []stateTestCase
	subtestName := ctx.String(testNameFlag.Name)
	if subtestName != "" {
		if subtest, ok := testsByName[subtestName]; ok {
			testsByName := make(map[string]tests.StateTest)
			testsByName[subtestName] = subtest
		}
	}
	idx := ctx.Int(idxFlag.Name)
	fork := ctx.String(forkFlag.Name)

	for key, test := range testsByName {
		for _, st := range test.Subtests() {
			if idx != -1 && st.Index != idx {
				continue
			}
			if fork != "" && st.Fork != fork {
				continue
			}
			res = append(res, stateTestCase{name: key, st: st, test: test})
		}
	}
	return res
}

// runStateTest loads the state-test given by fname, and executes the test.
func runStateTest(ctx *cli.Context, fname string, cfg vm.Config, dump bool, bench bool) error {
	src, err := os.ReadFile(fname)
	if err != nil {
		return err
	}
	var testsByName map[string]tests.StateTest
	if err := json.Unmarshal(src, &testsByName); err != nil {
		return err
	}

	matchingTests := collectMatchedSubtests(ctx, testsByName)

	// Iterate over all the tests, run them and aggregate the results
	var results []StatetestResult
	for _, test := range matchingTests {
		// Run the test and aggregate the result
		result := &StatetestResult{Name: test.name, Fork: test.st.Fork, Pass: true}
		test.test.Run(test.st, cfg, false, rawdb.HashScheme, func(err error, tstate *tests.StateTestState) {
			var root common.Hash
			if tstate.StateDB != nil {
				root = tstate.StateDB.IntermediateRoot(false)
				result.Root = &root
				fmt.Fprintf(os.Stderr, "{\"stateRoot\": \"%#x\"}\n", root)
				if dump { // Dump any state to aid debugging
					cpy, _ := state.New(root, tstate.StateDB.Database())
					dump := cpy.RawDump(nil)
					result.State = &dump
				}
			}
			if err != nil {
				// Test failed, mark as so
				result.Pass, result.Error = false, err.Error()
			}
		})
		if bench {
			_, stats, _ := timedExec(true, func() ([]byte, uint64, error) {
				_, _, gasUsed, _ := test.test.RunNoVerify(test.st, cfg, false, rawdb.HashScheme)
				return nil, gasUsed, nil
			})
			result.BenchStats = &stats
		}
		results = append(results, *result)
	}
	out, _ := json.MarshalIndent(results, "", "  ")
	fmt.Println(string(out))
	return nil
}