// VulcanizeDB
// Copyright © 2018 Vulcanize

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program 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 Affero General Public License for more details.

// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"log"
	"os"
	"time"

	"github.com/spf13/cobra"

	"github.com/vulcanize/vulcanizedb/pkg/core"
	"github.com/vulcanize/vulcanizedb/pkg/datastore"
	"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres/repositories"
	"github.com/vulcanize/vulcanizedb/pkg/history"
	"github.com/vulcanize/vulcanizedb/utils"
)

// syncCmd represents the sync command
var syncCmd = &cobra.Command{
	Use:   "sync",
	Short: "Syncs VulcanizeDB with local ethereum node",
	Long: `Syncs VulcanizeDB with local ethereum node. Populates
Postgres with blocks, transactions, receipts, and logs.

./vulcanizedb sync --starting-block-number 0 --config public.toml

Expects ethereum node to be running and requires a .toml config:

  [database]
  name = "vulcanize_public"
  hostname = "localhost"
  port = 5432

  [client]
  ipcPath = "/Users/user/Library/Ethereum/geth.ipc"
`,
	Run: func(cmd *cobra.Command, args []string) {
		sync()
	},
}

const (
	pollingInterval  = 7 * time.Second
	validationWindow = 15
)

func init() {
	rootCmd.AddCommand(syncCmd)

	syncCmd.Flags().Int64VarP(&startingBlockNumber, "starting-block-number", "s", 0, "Block number to start syncing from")
}

func backFillAllBlocks(blockchain core.BlockChain, blockRepository datastore.BlockRepository, missingBlocksPopulated chan int, startingBlockNumber int64) {
	missingBlocksPopulated <- history.PopulateMissingBlocks(blockchain, blockRepository, startingBlockNumber)
}

func sync() {
	ticker := time.NewTicker(pollingInterval)
	defer ticker.Stop()

	blockChain := getBlockChain()

	lastBlock := blockChain.LastBlock().Int64()
	if lastBlock == 0 {
		log.Fatal("geth initial: state sync not finished")
	}
	if startingBlockNumber > lastBlock {
		log.Fatal("starting block number > current block number")
	}

	db := utils.LoadPostgres(databaseConfig, blockChain.Node())
	blockRepository := repositories.NewBlockRepository(&db)
	validator := history.NewBlockValidator(blockChain, blockRepository, validationWindow)
	missingBlocksPopulated := make(chan int)
	go backFillAllBlocks(blockChain, blockRepository, missingBlocksPopulated, startingBlockNumber)

	for {
		select {
		case <-ticker.C:
			window := validator.ValidateBlocks()
			window.Log(os.Stdout)
		case <-missingBlocksPopulated:
			go backFillAllBlocks(blockChain, blockRepository, missingBlocksPopulated, startingBlockNumber)
		}
	}
}