package l2db

import (
	"fmt"
	"time"

	ethCommon "github.com/ethereum/go-ethereum/common"
	"github.com/gobuffalo/packr/v2"
	"github.com/hermeznetwork/hermez-node/common"
	"github.com/hermeznetwork/hermez-node/db"
	"github.com/jmoiron/sqlx"

	//nolint:errcheck // driver for postgres DB
	_ "github.com/lib/pq"
	migrate "github.com/rubenv/sql-migrate"
	"github.com/russross/meddler"
)

// TODO(Edu): Check DB consistency while there's concurrent use from Coordinator/TxSelector & API

// L2DB stores L2 txs and authorization registers received by the coordinator and keeps them until they are no longer relevant
// due to them being forged or invalid after a safety period
type L2DB struct {
	db           *sqlx.DB
	safetyPeriod common.BatchNum
	ttl          time.Duration
	maxTxs       uint32
}

// NewL2DB creates a L2DB.
// To create it, it's needed postgres configuration, safety period expressed in batches,
// maxTxs that the DB should have and TTL (time to live) for pending txs.
func NewL2DB(
	port int, host, user, password, dbname string,
	safetyPeriod common.BatchNum,
	maxTxs uint32,
	TTL time.Duration,
) (*L2DB, error) {
	// init meddler
	db.InitMeddler()
	meddler.Default = meddler.PostgreSQL
	// Stablish DB connection
	psqlconn := fmt.Sprintf("host=%s port=%d user=%s password=%s dbname=%s sslmode=disable", host, port, user, password, dbname)
	db, err := sqlx.Connect("postgres", psqlconn)
	if err != nil {
		return nil, err
	}

	// Run DB migrations
	migrations := &migrate.PackrMigrationSource{
		Box: packr.New("history-migrations", "./migrations"),
	}
	if _, err := migrate.Exec(db.DB, "postgres", migrations, migrate.Up); err != nil {
		return nil, err
	}

	return &L2DB{
		db:           db,
		safetyPeriod: safetyPeriod,
		ttl:          TTL,
		maxTxs:       maxTxs,
	}, nil
}

// DB returns a pointer to the L2DB.db. This method should be used only for
// internal testing purposes.
func (l2db *L2DB) DB() *sqlx.DB {
	return l2db.db
}

// AddAccountCreationAuth inserts an account creation authorization into the DB
func (l2db *L2DB) AddAccountCreationAuth(auth *common.AccountCreationAuth) error {
	return meddler.Insert(l2db.db, "account_creation_auth", auth)
}

// GetAccountCreationAuth returns an account creation authorization into the DB
func (l2db *L2DB) GetAccountCreationAuth(addr ethCommon.Address) (*common.AccountCreationAuth, error) {
	auth := new(common.AccountCreationAuth)
	return auth, meddler.QueryRow(
		l2db.db, auth,
		"SELECT * FROM account_creation_auth WHERE eth_addr = $1;",
		addr,
	)
}

// AddTx inserts a tx into the L2DB
func (l2db *L2DB) AddTx(tx *common.PoolL2Tx) error {
	return meddler.Insert(l2db.db, "tx_pool", tx)
}

// GetTx return the specified Tx
func (l2db *L2DB) GetTx(txID common.TxID) (*common.PoolL2Tx, error) {
	tx := new(common.PoolL2Tx)
	return tx, meddler.QueryRow(
		l2db.db, tx,
		"SELECT * FROM tx_pool WHERE tx_id = $1;",
		txID,
	)
}

// GetPendingTxs return all the pending txs of the L2DB
func (l2db *L2DB) GetPendingTxs() ([]*common.PoolL2Tx, error) {
	var txs []*common.PoolL2Tx
	err := meddler.QueryAll(
		l2db.db, &txs,
		"SELECT * FROM tx_pool WHERE state = $1",
		common.PoolL2TxStatePending,
	)
	return txs, err
}

// StartForging updates the state of the transactions that will begin the forging process.
// The state of the txs referenced by txIDs will be changed from Pending -> Forging
func (l2db *L2DB) StartForging(txIDs []common.TxID, batchNum common.BatchNum) error {
	query, args, err := sqlx.In(
		`UPDATE tx_pool
		SET state = ?, batch_num = ?
		WHERE state = ? AND tx_id IN (?);`,
		common.PoolL2TxStateForging,
		batchNum,
		common.PoolL2TxStatePending,
		txIDs,
	)
	if err != nil {
		return err
	}
	query = l2db.db.Rebind(query)
	_, err = l2db.db.Exec(query, args...)
	return err
}

// DoneForging updates the state of the transactions that have been forged
// so the state of the txs referenced by txIDs will be changed from Forging -> Forged
func (l2db *L2DB) DoneForging(txIDs []common.TxID, batchNum common.BatchNum) error {
	query, args, err := sqlx.In(
		`UPDATE tx_pool
		SET state = ?, batch_num = ?
		WHERE state = ? AND tx_id IN (?);`,
		common.PoolL2TxStateForged,
		batchNum,
		common.PoolL2TxStateForging,
		txIDs,
	)
	if err != nil {
		return err
	}
	query = l2db.db.Rebind(query)
	_, err = l2db.db.Exec(query, args...)
	return err
}

// InvalidateTxs updates the state of the transactions that are invalid.
// The state of the txs referenced by txIDs will be changed from * -> Invalid
func (l2db *L2DB) InvalidateTxs(txIDs []common.TxID, batchNum common.BatchNum) error {
	query, args, err := sqlx.In(
		`UPDATE tx_pool
		SET state = ?, batch_num = ?
		WHERE tx_id IN (?);`,
		common.PoolL2TxStateInvalid,
		batchNum,
		txIDs,
	)
	if err != nil {
		return err
	}
	query = l2db.db.Rebind(query)
	_, err = l2db.db.Exec(query, args...)
	return err
}

// CheckNonces invalidate txs with nonces that are smaller or equal than their respective accounts nonces.
// The state of the affected txs will be changed from Pending -> Invalid
func (l2db *L2DB) CheckNonces(updatedAccounts []common.Account, batchNum common.BatchNum) error {
	txn, err := l2db.db.Begin()
	if err != nil {
		return err
	}
	defer func() {
		// Rollback the transaction if there was an error.
		if err != nil {
			err = txn.Rollback()
		}
	}()
	for i := 0; i < len(updatedAccounts); i++ {
		_, err = txn.Exec(
			`UPDATE tx_pool
			SET state = $1, batch_num = $2
			WHERE state = $3 AND from_idx = $4 AND nonce <= $5;`,
			common.PoolL2TxStateInvalid,
			batchNum,
			common.PoolL2TxStatePending,
			updatedAccounts[i].Idx,
			updatedAccounts[i].Nonce,
		)
		if err != nil {
			return err
		}
	}
	return txn.Commit()
}

// UpdateTxValue updates the absolute fee and value of txs given a token list that include their price in USD
func (l2db *L2DB) UpdateTxValue(tokens []common.Token) error {
	// WARNING: this is very slow and should be optimized
	txn, err := l2db.db.Begin()
	if err != nil {
		return err
	}
	defer func() {
		// Rollback the transaction if there was an error.
		if err != nil {
			err = txn.Rollback()
		}
	}()
	now := time.Now()
	for i := 0; i < len(tokens); i++ {
		_, err = txn.Exec(
			`UPDATE tx_pool
			SET usd_update = $1, value_usd = amount_f * $2, fee_usd = $2 * amount_f * CASE
				WHEN fee = 0 THEN 0	
				WHEN fee >= 1 AND fee <= 32 THEN POWER(10,-24+(fee::float/2))	
				WHEN fee >= 33 AND fee <= 223 THEN POWER(10,-8+(0.041666666666667*(fee::float-32)))	
				WHEN fee >= 224 AND fee <= 255 THEN POWER(10,fee-224) END
			WHERE token_id = $3;`,
			now,
			tokens[i].USD,
			tokens[i].TokenID,
		)
		if err != nil {
			return err
		}
	}
	return txn.Commit()
}

// Reorg updates the state of txs that were updated in a batch that has been discarted due to a blockchain reorg.
// The state of the affected txs can change form Forged -> Pending or from Invalid -> Pending
func (l2db *L2DB) Reorg(lastValidBatch common.BatchNum) error {
	_, err := l2db.db.Exec(
		`UPDATE tx_pool SET batch_num = NULL, state = $1 
		WHERE (state = $2 OR state = $3) AND batch_num > $4`,
		common.PoolL2TxStatePending,
		common.PoolL2TxStateForged,
		common.PoolL2TxStateInvalid,
		lastValidBatch,
	)
	return err
}

// Purge deletes transactions that have been forged or marked as invalid for longer than the safety period
// it also deletes txs that has been in the L2DB for longer than the ttl if maxTxs has been exceeded
func (l2db *L2DB) Purge(currentBatchNum common.BatchNum) error {
	txn, err := l2db.db.Begin()
	if err != nil {
		return err
	}
	defer func() {
		// Rollback the transaction if there was an error.
		if err != nil {
			err = txn.Rollback()
		}
	}()
	// Delete pending txs that have been in the pool after the TTL if maxTxs is reached
	now := time.Now().UTC().Unix()
	_, err = txn.Exec(
		`DELETE FROM tx_pool WHERE (SELECT count(*) FROM tx_pool) > $1 AND timestamp < $2`,
		l2db.maxTxs,
		time.Unix(now-int64(l2db.ttl.Seconds()), 0),
	)
	if err != nil {
		return err
	}
	// Delete txs that have been marked as forged / invalid after the safety period
	_, err = txn.Exec(
		`DELETE FROM tx_pool 
		WHERE batch_num < $1 AND (state = $2 OR state = $3)`,
		currentBatchNum-l2db.safetyPeriod,
		common.PoolL2TxStateForged,
		common.PoolL2TxStateInvalid,
	)
	if err != nil {
		return err
	}
	return txn.Commit()
}

// Close frees the resources used by the L2DB
func (l2db *L2DB) Close() error {
	return l2db.db.Close()
}