package cmd

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

	ind "github.com/cerc-io/plugeth-statediff/indexer"
	"github.com/cerc-io/plugeth-statediff/utils/log"
	"github.com/ethereum/go-ethereum/params"
	"github.com/ethereum/go-ethereum/trie"
	"github.com/spf13/viper"

	sd "github.com/vulcanize/eth-statediff-service/pkg"
)

type blockRange [2]uint64

func createStateDiffService() *sd.Service {
	// load some necessary params
	logWithCommand.Info("Loading statediff service parameters")
	mode := viper.GetString("leveldb.mode")
	path := viper.GetString("leveldb.path")
	ancientPath := viper.GetString("leveldb.ancient")
	url := viper.GetString("leveldb.url")

	if mode == "local" {
		if path == "" || ancientPath == "" {
			logWithCommand.Fatal("Require a valid eth LevelDB primary datastore path and ancient datastore path")
		}
	} else if mode == "remote" {
		if url == "" {
			logWithCommand.Fatal("Require a valid RPC url for accessing LevelDB")
		}
	} else {
		logWithCommand.Fatal("Invalid mode provided for LevelDB access")
	}

	nodeInfo := getEthNodeInfo()

	var chainConf *params.ChainConfig
	var err error
	chainConfigPath := viper.GetString("ethereum.chainConfig")
	chainConf, err = LoadConfig(chainConfigPath)
	if err != nil {
		logWithCommand.Fatal(err)
	}

	// create LevelDB reader
	logWithCommand.Info("Creating LevelDB reader")
	readerConf := sd.LvLDBReaderConfig{
		TrieConfig: &trie.Config{
			Cache:     viper.GetInt("cache.trie"),
			Journal:   "",
			Preimages: false,
		},
		ChainConfig: chainConf,
		Mode:        mode,
		Path:        path,
		AncientPath: ancientPath,
		Url:         url,
		DBCacheSize: viper.GetInt("cache.database"),
	}
	lvlDBReader, err := sd.NewLvlDBReader(readerConf)
	if err != nil {
		logWithCommand.Fatal(err)
	}

	// create statediff service
	logWithCommand.Info("Setting up database")
	conf, err := getConfig(nodeInfo)
	if err != nil {
		logWithCommand.Fatal(err)
	}
	logWithCommand.Info("Creating statediff indexer")
	_, indexer, err := ind.NewStateDiffIndexer(context.Background(), chainConf, nodeInfo, conf)
	if err != nil {
		logWithCommand.Fatal(err)
	}
	logWithCommand.Info("Creating statediff service")
	sdConf := sd.ServiceConfig{
		ServiceWorkers:  viper.GetUint("statediff.serviceWorkers"),
		TrieWorkers:     viper.GetUint("statediff.trieWorkers"),
		WorkerQueueSize: viper.GetUint("statediff.workerQueueSize"),
	}
	return sd.NewStateDiffService(lvlDBReader, indexer, sdConf)
}

// LoadConfig loads chain config from json file
func LoadConfig(chainConfigPath string) (*params.ChainConfig, error) {
	file, err := os.Open(chainConfigPath)
	if err != nil {
		log.Error(fmt.Sprintf("Failed to read chain config file: %v", err))

		return nil, err
	}
	defer file.Close()

	chainConfig := new(params.ChainConfig)
	if err := json.NewDecoder(file).Decode(chainConfig); err != nil {
		log.Error(fmt.Sprintf("invalid chain config file: %v", err))

		return nil, err
	}

	log.Info(fmt.Sprintf("Using chain config from %s file. Content %+v", chainConfigPath, chainConfig))

	return chainConfig, nil
}