// Package clickhouse writes batches of telemetry readings to ClickHouse.
package clickhouse

import (
	"context"
	"crypto/tls"
	"fmt"

	ch "github.com/ClickHouse/clickhouse-go/v2"
	"github.com/ClickHouse/clickhouse-go/v2/lib/driver"

	"git.cactoz.su/cacto/home_automatization/services/ingest-service/internal/telemetry"
)

type Config struct {
	Addr     string
	Database string
	Username string
	Password string
	UseTLS   bool
}

type Store struct {
	conn driver.Conn
}

func Connect(ctx context.Context, cfg Config) (*Store, error) {
	opts := &ch.Options{
		Addr: []string{cfg.Addr},
		Auth: ch.Auth{
			Database: cfg.Database,
			Username: cfg.Username,
			Password: cfg.Password,
		},
	}
	if cfg.UseTLS {
		opts.TLS = &tls.Config{}
	}

	conn, err := ch.Open(opts)
	if err != nil {
		return nil, fmt.Errorf("open clickhouse connection: %w", err)
	}
	if err := conn.Ping(ctx); err != nil {
		return nil, fmt.Errorf("ping clickhouse: %w", err)
	}
	return &Store{conn: conn}, nil
}

func (s *Store) Close() error {
	return s.conn.Close()
}

// InsertBatch writes readings to the telemetry table in a single INSERT.
func (s *Store) InsertBatch(ctx context.Context, readings []telemetry.Reading) error {
	if len(readings) == 0 {
		return nil
	}

	batch, err := s.conn.PrepareBatch(ctx, "INSERT INTO telemetry (device_id, zone_id, sensor_type, value, recorded_at, received_at)")
	if err != nil {
		return fmt.Errorf("prepare batch: %w", err)
	}
	defer batch.Close()

	for _, r := range readings {
		if err := batch.Append(r.DeviceID, r.ZoneID, r.SensorType, r.Value, r.RecordedAt, r.ReceivedAt); err != nil {
			return fmt.Errorf("append reading for device %s: %w", r.DeviceID, err)
		}
	}

	if err := batch.Send(); err != nil {
		return fmt.Errorf("send batch: %w", err)
	}
	return nil
}