// VulcanizeDB
// Copyright © 2022 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 file

import (
	"encoding/csv"
	"errors"
	"fmt"
	"math/big"
	"os"
	"path/filepath"
	"strconv"

	"github.com/ethereum/go-ethereum/common"
	"github.com/thoas/go-funk"

	"github.com/cerc-io/plugeth-statediff/indexer/database/metrics"
	"github.com/cerc-io/plugeth-statediff/indexer/ipld"
	"github.com/cerc-io/plugeth-statediff/indexer/models"
	nodeinfo "github.com/cerc-io/plugeth-statediff/indexer/node"
	"github.com/cerc-io/plugeth-statediff/indexer/shared/schema"
	sdtypes "github.com/cerc-io/plugeth-statediff/types"
)

type tableRow struct {
	table  *schema.Table
	values []interface{}
}

type CSVWriter struct {
	// dir containing output files
	dir    string
	isDiff bool

	writers                fileWriters
	watchedAddressesWriter fileWriter

	rows          chan tableRow
	flushChan     chan struct{}
	flushFinished chan struct{}
	quitChan      chan struct{}
	doneChan      chan struct{}
}

type fileWriter struct {
	*csv.Writer
	file *os.File
}

// fileWriters wraps the file writers for each output table
type fileWriters map[string]fileWriter

func newFileWriter(path string) (ret fileWriter, err error) {
	file, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644)
	if err != nil {
		return
	}

	ret = fileWriter{
		Writer: csv.NewWriter(file),
		file:   file,
	}

	return
}

func makeFileWriters(dir string, tables []*schema.Table) (fileWriters, error) {
	writers := fileWriters{}
	for _, tbl := range tables {
		w, err := newFileWriter(TableFilePath(dir, tbl.Name))
		if err != nil {
			return nil, err
		}
		writers[tbl.Name] = w
	}
	return writers, nil
}

func (tx fileWriters) write(tbl *schema.Table, args ...interface{}) error {
	row := tbl.ToCsvRow(args...)
	return tx[tbl.Name].Write(row)
}

func (tx fileWriters) close() error {
	for _, w := range tx {
		err := w.file.Close()
		if err != nil {
			return err
		}
	}
	return nil
}

func (tx fileWriters) flush() error {
	for _, w := range tx {
		w.Flush()
		if err := w.Error(); err != nil {
			return err
		}
	}
	return nil
}

func NewCSVWriter(path string, watchedAddressesFilePath string, diff bool) (*CSVWriter, error) {
	if err := os.MkdirAll(path, 0777); err != nil {
		return nil, fmt.Errorf("unable to create directory '%s': %w", path, err)
	}

	writers, err := makeFileWriters(path, schema.Tables)
	if err != nil {
		return nil, err
	}

	watchedAddressesWriter, err := newFileWriter(watchedAddressesFilePath)
	if err != nil {
		return nil, err
	}

	csvWriter := &CSVWriter{
		writers:                writers,
		watchedAddressesWriter: watchedAddressesWriter,
		dir:                    path,
		isDiff:                 diff,
		rows:                   make(chan tableRow),
		flushChan:              make(chan struct{}),
		flushFinished:          make(chan struct{}),
		quitChan:               make(chan struct{}),
		doneChan:               make(chan struct{}),
	}
	return csvWriter, nil
}

func (csw *CSVWriter) Loop() {
	go func() {
		defer close(csw.doneChan)
		for {
			select {
			case row := <-csw.rows:
				err := csw.writers.write(row.table, row.values...)
				if err != nil {
					panic(fmt.Sprintf("error writing csv buffer: %v", err))
				}
			case <-csw.quitChan:
				if err := csw.writers.flush(); err != nil {
					panic(fmt.Sprintf("error writing csv buffer to file: %v", err))
				}
				return
			case <-csw.flushChan:
				if err := csw.writers.flush(); err != nil {
					panic(fmt.Sprintf("error writing csv buffer to file: %v", err))
				}
				csw.flushFinished <- struct{}{}
			}
		}
	}()
}

// Flush sends a flush signal to the looping process
func (csw *CSVWriter) Flush() {
	csw.flushChan <- struct{}{}
	<-csw.flushFinished
}

func TableFilePath(dir, name string) string { return filepath.Join(dir, name+".csv") }

// Close satisfies io.Closer
func (csw *CSVWriter) Close() error {
	close(csw.quitChan)
	<-csw.doneChan
	close(csw.rows)
	close(csw.flushChan)
	close(csw.flushFinished)
	return csw.writers.close()
}

func (csw *CSVWriter) upsertNode(node nodeinfo.Info) {
	var values []interface{}
	values = append(values, node.GenesisBlock, node.NetworkID, node.ID, node.ClientName, node.ChainID)
	csw.rows <- tableRow{&schema.TableNodeInfo, values}
}

func (csw *CSVWriter) upsertIPLD(ipld models.IPLDModel) {
	var values []interface{}
	values = append(values, ipld.BlockNumber, ipld.Key, ipld.Data)
	csw.rows <- tableRow{&schema.TableIPLDBlock, values}
}

func (csw *CSVWriter) upsertIPLDDirect(blockNumber, key string, value []byte) {
	csw.upsertIPLD(models.IPLDModel{
		BlockNumber: blockNumber,
		Key:         key,
		Data:        value,
	})
}

func (csw *CSVWriter) upsertIPLDNode(blockNumber string, i ipld.IPLD) {
	csw.upsertIPLD(models.IPLDModel{
		BlockNumber: blockNumber,
		Key:         i.Cid().String(),
		Data:        i.RawData(),
	})
}

func (csw *CSVWriter) upsertHeaderCID(header models.HeaderModel) {
	var values []interface{}
	values = append(values,
		header.BlockNumber,
		header.BlockHash,
		header.ParentHash,
		header.CID,
		header.TotalDifficulty,
		header.NodeIDs,
		header.Reward,
		header.StateRoot,
		header.TxRoot,
		header.RctRoot,
		header.UnclesHash,
		header.Bloom,
		strconv.FormatUint(header.Timestamp, 10),
		header.Coinbase,
		header.Canonical,
		header.WithdrawalsRoot,
	)
	csw.rows <- tableRow{&schema.TableHeader, values}
	metrics.IndexerMetrics.BlocksCounter.Inc(1)
}

func (csw *CSVWriter) upsertUncleCID(uncle models.UncleModel) {
	var values []interface{}
	values = append(values, uncle.BlockNumber, uncle.BlockHash, uncle.HeaderID, uncle.ParentHash, uncle.CID,
		uncle.Reward, uncle.Index)
	csw.rows <- tableRow{&schema.TableUncle, values}
}

func (csw *CSVWriter) upsertTransactionCID(transaction models.TxModel) {
	var values []interface{}
	values = append(values, transaction.BlockNumber, transaction.HeaderID, transaction.TxHash, transaction.CID, transaction.Dst,
		transaction.Src, transaction.Index, transaction.Type, transaction.Value)
	csw.rows <- tableRow{&schema.TableTransaction, values}
	metrics.IndexerMetrics.TransactionsCounter.Inc(1)
}

func (csw *CSVWriter) upsertReceiptCID(rct *models.ReceiptModel) {
	var values []interface{}
	values = append(values, rct.BlockNumber, rct.HeaderID, rct.TxID, rct.CID, rct.Contract,
		rct.PostState, rct.PostStatus)
	csw.rows <- tableRow{&schema.TableReceipt, values}
	metrics.IndexerMetrics.ReceiptsCounter.Inc(1)
}

func (csw *CSVWriter) upsertLogCID(logs []*models.LogsModel) {
	for _, l := range logs {
		var values []interface{}
		values = append(values, l.BlockNumber, l.HeaderID, l.CID, l.ReceiptID, l.Address, l.Index, l.Topic0,
			l.Topic1, l.Topic2, l.Topic3)
		csw.rows <- tableRow{&schema.TableLog, values}
		metrics.IndexerMetrics.LogsCounter.Inc(1)
	}
}

func (csw *CSVWriter) upsertWithdrawalCID(withdrawal models.WithdrawalModel) {
	var values []interface{}
	values = append(values,
		withdrawal.BlockNumber,
		withdrawal.HeaderID,
		withdrawal.CID,
		withdrawal.Index,
		withdrawal.Validator,
		withdrawal.Address,
		withdrawal.Amount,
	)
	csw.rows <- tableRow{&schema.TableWithdrawal, values}
	metrics.IndexerMetrics.WithdrawalsCounter.Inc(1)
}

func (csw *CSVWriter) upsertStateCID(stateNode models.StateNodeModel) {
	balance := stateNode.Balance
	if stateNode.Removed {
		balance = "0"
	}

	var values []interface{}
	values = append(values, stateNode.BlockNumber, stateNode.HeaderID, stateNode.StateKey, stateNode.CID,
		csw.isDiff, balance, strconv.FormatUint(stateNode.Nonce, 10), stateNode.CodeHash, stateNode.StorageRoot, stateNode.Removed)
	csw.rows <- tableRow{&schema.TableStateNode, values}
}

func (csw *CSVWriter) upsertStorageCID(storageCID models.StorageNodeModel) {
	var values []interface{}
	values = append(values, storageCID.BlockNumber, storageCID.HeaderID, storageCID.StateKey, storageCID.StorageKey, storageCID.CID,
		csw.isDiff, storageCID.Value, storageCID.Removed)
	csw.rows <- tableRow{&schema.TableStorageNode, values}
}

// LoadWatchedAddresses loads watched addresses from a file
func (csw *CSVWriter) loadWatchedAddresses() ([]common.Address, error) {
	watchedAddressesFilePath := csw.watchedAddressesWriter.file.Name()
	// load csv rows from watched addresses file
	rows, err := loadWatchedAddressesRows(watchedAddressesFilePath)
	if err != nil {
		return nil, err
	}

	// extract addresses from the csv rows
	watchedAddresses := funk.Map(rows, func(row []string) common.Address {
		// first column is for address in eth_meta.watched_addresses
		addressString := row[0]

		return common.HexToAddress(addressString)
	}).([]common.Address)

	return watchedAddresses, nil
}

// InsertWatchedAddresses inserts the given addresses in a file
func (csw *CSVWriter) insertWatchedAddresses(args []sdtypes.WatchAddressArg, currentBlockNumber *big.Int) error {
	// load csv rows from watched addresses file
	watchedAddresses, err := csw.loadWatchedAddresses()
	if err != nil {
		return err
	}

	// append rows for new addresses to existing csv file
	for _, arg := range args {
		// ignore if already watched
		if funk.Contains(watchedAddresses, common.HexToAddress(arg.Address)) {
			continue
		}

		var values []interface{}
		values = append(values, arg.Address, strconv.FormatUint(arg.CreatedAt, 10), currentBlockNumber.String(), "0")
		row := schema.TableWatchedAddresses.ToCsvRow(values...)

		// writing directly instead of using rows channel as it needs to be flushed immediately
		err = csw.watchedAddressesWriter.Write(row)
		if err != nil {
			return err
		}
	}

	// watched addresses need to be flushed immediately to the file to keep them in sync with in-memory watched addresses
	csw.watchedAddressesWriter.Flush()
	err = csw.watchedAddressesWriter.Error()
	if err != nil {
		return err
	}

	return nil
}

// RemoveWatchedAddresses removes the given watched addresses from a file
func (csw *CSVWriter) removeWatchedAddresses(args []sdtypes.WatchAddressArg) error {
	// load csv rows from watched addresses file
	watchedAddressesFilePath := csw.watchedAddressesWriter.file.Name()
	rows, err := loadWatchedAddressesRows(watchedAddressesFilePath)
	if err != nil {
		return err
	}

	// get rid of rows having addresses to be removed
	filteredRows := funk.Filter(rows, func(row []string) bool {
		return !funk.Contains(args, func(arg sdtypes.WatchAddressArg) bool {
			// Compare first column in table for address
			return arg.Address == row[0]
		})
	}).([][]string)

	return dumpWatchedAddressesRows(csw.watchedAddressesWriter, filteredRows)
}

// SetWatchedAddresses clears and inserts the given addresses in a file
func (csw *CSVWriter) setWatchedAddresses(args []sdtypes.WatchAddressArg, currentBlockNumber *big.Int) error {
	var rows [][]string
	for _, arg := range args {
		row := schema.TableWatchedAddresses.ToCsvRow(arg.Address, strconv.FormatUint(arg.CreatedAt, 10), currentBlockNumber.String(), "0")
		rows = append(rows, row)
	}

	return dumpWatchedAddressesRows(csw.watchedAddressesWriter, rows)
}

// loadCSVWatchedAddresses loads csv rows from the given file
func loadWatchedAddressesRows(filePath string) ([][]string, error) {
	file, err := os.Open(filePath)
	if err != nil {
		if errors.Is(err, os.ErrNotExist) {
			return [][]string{}, nil
		}

		return nil, fmt.Errorf("error opening watched addresses file: %w", err)
	}

	defer file.Close()
	reader := csv.NewReader(file)

	return reader.ReadAll()
}

// dumpWatchedAddressesRows dumps csv rows to the given file
func dumpWatchedAddressesRows(watchedAddressesWriter fileWriter, filteredRows [][]string) error {
	file := watchedAddressesWriter.file
	file.Close()

	file, err := os.Create(file.Name())
	if err != nil {
		return fmt.Errorf("error creating watched addresses file: %w", err)
	}

	watchedAddressesWriter.Writer = csv.NewWriter(file)
	watchedAddressesWriter.file = file

	for _, row := range filteredRows {
		watchedAddressesWriter.Write(row)
	}

	watchedAddressesWriter.Flush()

	return nil
}