// 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 core

import (
	"testing"
	"time"

	"github.com/XinFinOrg/XDPoSChain/consensus/ethash"
	"github.com/XinFinOrg/XDPoSChain/core/rawdb"
	"github.com/XinFinOrg/XDPoSChain/core/types"
	"github.com/XinFinOrg/XDPoSChain/core/vm"
	"github.com/XinFinOrg/XDPoSChain/params"
)

// Tests that simple header verification works, for both good and bad blocks.
func TestHeaderVerification(t *testing.T) {
	// Create a simple chain to verify
	var (
		testdb    = rawdb.NewMemoryDatabase()
		gspec     = &Genesis{Config: params.TestChainConfig}
		genesis   = gspec.MustCommit(testdb)
		blocks, _ = GenerateChain(gspec.Config, genesis, ethash.NewFaker(), testdb, 8, nil)
	)
	headers := make([]*types.Header, len(blocks))
	for i, block := range blocks {
		headers[i] = block.Header()
	}
	// Run the header checker for blocks one-by-one, checking for both valid and invalid nonces
	chain, err := NewBlockChain(testdb, nil, gspec, ethash.NewFaker(), vm.Config{})
	defer chain.Stop()
	if err != nil {
		t.Fatal(err)
	}

	for i := 0; i < len(blocks); i++ {
		for j, valid := range []bool{true, false} {
			var results <-chan error
			if valid {
				engine := ethash.NewFaker()
				_, results = engine.VerifyHeaders(chain, []*types.Header{headers[i]}, []bool{true})
			} else {
				engine := ethash.NewFakeFailer(headers[i].Number.Uint64())
				_, results = engine.VerifyHeaders(chain, []*types.Header{headers[i]}, []bool{true})
			}
			// Wait for the verification result
			select {
			case result := <-results:
				if (result == nil) != valid {
					t.Errorf("test %d.%d: validity mismatch: have %v, want %v", i, j, result, valid)
				}
			case <-time.After(time.Second):
				t.Fatalf("test %d.%d: verification timeout", i, j)
			}
			// Make sure no more data is returned
			select {
			case result := <-results:
				t.Fatalf("test %d.%d: unexpected result returned: %v", i, j, result)
			case <-time.After(25 * time.Millisecond):
			}
		}
		chain.InsertChain(blocks[i : i+1])
	}
}