Make a genesis block

main.go

// Copyright 2019 cruzbit developers
// Use of this source code is governed by a MIT-style license that can be found in the LICENSE file.

package main

import (
	"encoding/base64"
	"encoding/hex"
	"encoding/json"
	"flag"
	"fmt"
	"log"
	"math/rand"
	"time"

	. "github.com/cruzbit/cruzbit"
	"golang.org/x/crypto/ed25519"
)

// Generate a genesis block
func main() {
	rand.Seed(time.Now().UnixNano())

	memoPtr := flag.String("memo", "", "A memo to include in the genesis block's coinbase memo field")
	pubKeyPtr := flag.String("pubkey", "", "A public key to include in the genesis block's coinbase output")
	flag.Parse()

	if len(*memoPtr) == 0 {
		log.Fatal("Memo required for genesis block")
	}

	if len(*pubKeyPtr) == 0 {
		log.Fatal("Public key required for genesis block")
	}

	pubKeyBytes, err := base64.StdEncoding.DecodeString(*pubKeyPtr)
	if err != nil {
		log.Fatal(err)
	}
	pubKey := ed25519.PublicKey(pubKeyBytes)

	// create the coinbase
	tx := NewTransaction(nil, pubKey, INITIAL_COINBASE_REWARD, 0, 0, 0, 0, *memoPtr)

	// create the block
	targetBytes, err := hex.DecodeString(INITIAL_TARGET)
	if err != nil {
		log.Fatal(err)
	}
	var target BlockID
	copy(target[:], targetBytes)
	block, err := NewBlock(BlockID{}, 0, target, BlockID{}, []*Transaction{tx})
	if err != nil {
		log.Fatal(err)
	}

	// mine it
	targetInt := block.Header.Target.GetBigInt()
	ticker := time.NewTicker(30 * time.Second)
done:
	for {
		select {
		case <-ticker.C:
			block.Header.Time = time.Now().Unix()
		default:
			// keep hashing until proof-of-work is satisfied
			idInt := block.Header.IDFast()
			if idInt.Cmp(targetInt) <= 0 {
				break done
			}
			block.Header.Nonce += 1
			if block.Header.Nonce > MAX_NUMBER {
				block.Header.Nonce = 0
			}
		}
	}

	blockJson, err := json.Marshal(block)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Printf("%s\n", blockJson)
}