// Copyright 2019 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 fourbyte

import (
	"fmt"
	"io/ioutil"
	"strings"
	"testing"

	"github.com/ethereum/go-ethereum/accounts/abi"
	"github.com/ethereum/go-ethereum/common"
)

// Tests that all the selectors contained in the 4byte database are valid.
func TestEmbeddedDatabase(t *testing.T) {
	db, err := New()
	if err != nil {
		t.Fatal(err)
	}
	for id, selector := range db.embedded {
		abistring, err := parseSelector(selector)
		if err != nil {
			t.Errorf("Failed to convert selector to ABI: %v", err)
			continue
		}
		abistruct, err := abi.JSON(strings.NewReader(string(abistring)))
		if err != nil {
			t.Errorf("Failed to parse ABI: %v", err)
			continue
		}
		m, err := abistruct.MethodById(common.Hex2Bytes(id))
		if err != nil {
			t.Errorf("Failed to get method by id (%s): %v", id, err)
			continue
		}
		if m.Sig != selector {
			t.Errorf("Selector mismatch: have %v, want %v", m.Sig, selector)
		}
	}
}

// Tests that custom 4byte datasets can be handled too.
func TestCustomDatabase(t *testing.T) {
	// Create a new custom 4byte database with no embedded component
	tmpdir, err := ioutil.TempDir("", "signer-4byte-test")
	if err != nil {
		t.Fatal(err)
	}
	filename := fmt.Sprintf("%s/4byte_custom.json", tmpdir)

	db, err := NewWithFile(filename)
	if err != nil {
		t.Fatal(err)
	}
	db.embedded = make(map[string]string)

	// Ensure the database is empty, insert and verify
	calldata := common.Hex2Bytes("a52c101edeadbeef")
	if _, err = db.Selector(calldata); err == nil {
		t.Fatalf("Should not find a match on empty database")
	}
	if err = db.AddSelector("send(uint256)", calldata); err != nil {
		t.Fatalf("Failed to save file: %v", err)
	}
	if _, err = db.Selector(calldata); err != nil {
		t.Fatalf("Failed to find a match for abi signature: %v", err)
	}
	// Check that the file as persisted to disk by creating a new instance
	db2, err := NewFromFile(filename)
	if err != nil {
		t.Fatalf("Failed to create new abidb: %v", err)
	}
	if _, err = db2.Selector(calldata); err != nil {
		t.Fatalf("Failed to find a match for persisted abi signature: %v", err)
	}
}