package transport

import (
	"context"
	"database/sql"
	"strings"
)

type ProcessedMessageIDsCache struct {
	db *sql.DB
}

func NewProcessedMessageIDsCache(db *sql.DB) *ProcessedMessageIDsCache {
	return &ProcessedMessageIDsCache{db: db}
}

func (c *ProcessedMessageIDsCache) Clear() error {
	_, err := c.db.Exec("DELETE FROM transport_message_cache")
	return err
}

func (c *ProcessedMessageIDsCache) Hits(ids []string) (map[string]bool, error) {
	hits := make(map[string]bool)
	idsArgs := make([]interface{}, 0, len(ids))
	for _, id := range ids {
		idsArgs = append(idsArgs, id)
	}

	inVector := strings.Repeat("?, ", len(ids)-1) + "?"
	query := "SELECT id FROM transport_message_cache WHERE id IN (" + inVector + ")" // nolint: gosec

	rows, err := c.db.Query(query, idsArgs...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	for rows.Next() {
		var id string
		err := rows.Scan(&id)
		if err != nil {
			return nil, err
		}
		hits[id] = true
	}

	return hits, nil
}

func (c *ProcessedMessageIDsCache) Add(ids []string, timestamp uint64) (err error) {
	var tx *sql.Tx
	tx, err = c.db.BeginTx(context.Background(), &sql.TxOptions{})
	if err != nil {
		return
	}

	defer func() {
		if err == nil {
			err = tx.Commit()
			return
		}
		// don't shadow original error
		_ = tx.Rollback()
	}()

	for _, id := range ids {

		var stmt *sql.Stmt
		stmt, err = tx.Prepare(`INSERT INTO transport_message_cache(id,timestamp) VALUES (?, ?)`)
		if err != nil {
			return
		}

		_, err = stmt.Exec(id, timestamp)
		if err != nil {
			return
		}
	}

	return
}

func (c *ProcessedMessageIDsCache) Clean(timestamp uint64) error {
	_, err := c.db.Exec(`DELETE FROM transport_message_cache WHERE timestamp < ?`, timestamp)
	return err
}