package db

import (
	"context"
	"database/sql"
	"fmt"
	"path/filepath"

	_ "github.com/lib/pq"

	"github.com/volker-raschek/flucky/pkg/types"
	"github.com/volker-raschek/go-logger/pkg/logger"
)

var (
	postgresAssetPath = "pkg/storage/postgres"
)

// Postgres implementation
type Postgres struct {
	dbo     *sql.DB
	flogger logger.Logger
}

// DeleteDevices from the database
func (postgres *Postgres) DeleteDevices(ctx context.Context, deviceIDs ...string) error {
	asset := filepath.Join(postgresAssetPath, "deleteDevice.sql")
	queryBytes, err := Asset(asset)
	if err != nil {
		return fmt.Errorf("Failed to load asset %v: %v", asset, err)
	}
	query := string(queryBytes)

	tx, err := postgres.dbo.BeginTx(ctx, &sql.TxOptions{ReadOnly: false})
	if err != nil {
		return fmt.Errorf("Failed to begin new transaction: %v", err)
	}

	stmt, err := tx.Prepare(query)
	if err != nil {
		return fmt.Errorf("Failed to prepare statement: %v", err)
	}
	defer stmt.Close()

	for _, deviceID := range deviceIDs {
		_, err = stmt.Exec(deviceID)
		if err != nil {
			tx.Rollback()
			return err
		}
	}

	return tx.Commit()
}

// DeleteSensors from the database
func (postgres *Postgres) DeleteSensors(ctx context.Context, sensorIDs ...string) error {
	asset := filepath.Join(postgresAssetPath, "deleteSensor.sql")
	queryBytes, err := Asset(asset)
	if err != nil {
		return fmt.Errorf("Failed to load asset %v: %v", asset, err)
	}
	query := string(queryBytes)

	tx, err := postgres.dbo.BeginTx(ctx, &sql.TxOptions{ReadOnly: false})
	if err != nil {
		return fmt.Errorf("Failed to begin new transaction: %v", err)
	}

	stmt, err := tx.Prepare(query)
	if err != nil {
		return fmt.Errorf("Failed to prepare statement: %v", err)
	}
	defer stmt.Close()

	for _, sensorID := range sensorIDs {
		_, err = stmt.Exec(sensorID)
		if err != nil {
			tx.Rollback()
			return err
		}
	}

	return tx.Commit()
}

// InsertDevices into the database
func (postgres *Postgres) InsertDevices(ctx context.Context, devices ...*types.Device) error {
	asset := filepath.Join(postgresAssetPath, "insertDevice.sql")
	queryBytes, err := Asset(asset)
	if err != nil {
		return fmt.Errorf("Failed to load asset %v: %v", asset, err)
	}
	query := string(queryBytes)

	tx, err := postgres.dbo.BeginTx(ctx, &sql.TxOptions{ReadOnly: false})
	if err != nil {
		return fmt.Errorf("Failed to begin new transaction: %v", err)
	}

	stmt, err := tx.Prepare(query)
	if err != nil {
		return fmt.Errorf("Failed to prepare statement: %v", err)
	}
	defer stmt.Close()

	for _, device := range devices {
		_, err = stmt.Exec(&device.ID, &device.Name, &device.Location, &device.CreationDate)
		if err != nil {
			tx.Rollback()
			return fmt.Errorf("Failed to execute statement: %v", err)
		}
	}

	return tx.Commit()
}

// InsertMeasuredValues into the database
func (postgres *Postgres) InsertMeasuredValues(ctx context.Context, measuredValues ...*types.MeasuredValue) error {
	splittedMeasuredValues := make(map[string][]*types.MeasuredValue, 0)

	for _, measuredValue := range measuredValues {
		if _, ok := splittedMeasuredValues[measuredValue.ValueType]; !ok {
			splittedMeasuredValues[measuredValue.ValueType] = make([]*types.MeasuredValue, 0)
		}
		splittedMeasuredValues[measuredValue.ValueType] = append(splittedMeasuredValues[measuredValue.ValueType], measuredValue)
	}

	tx, err := postgres.dbo.BeginTx(ctx, &sql.TxOptions{ReadOnly: false})
	if err != nil {
		return fmt.Errorf("Failed to begin new transaction: %v", err)
	}

	// General insert function
	insert := func(tx *sql.Tx, asset string, measuredValues []*types.MeasuredValue) error {
		queryBytes, err := Asset(asset)
		if err != nil {
			return fmt.Errorf("Failed to load asset %v: %v", asset, err)
		}
		query := string(queryBytes)

		stmt, err := tx.Prepare(query)
		if err != nil {
			return fmt.Errorf("Failed to prepare statement: %v", err)
		}
		defer stmt.Close()

		for _, measuredValue := range measuredValues {
			_, err := stmt.Exec(&measuredValue.ID, &measuredValue.Value, &measuredValue.SensorID, &measuredValue.CreationDate)
			if err != nil {
				return fmt.Errorf("Failed to execute statement: %v", err)
			}
		}

		return nil
	}

	for measuredValueType, measuredValues := range splittedMeasuredValues {
		var asset string

		switch measuredValueType {
		case "humidity":
			asset = filepath.Join(postgresAssetPath, "insertHumidity.sql")
		case "pressure":
			asset = filepath.Join(postgresAssetPath, "insertPressure.sql")
		case "temperature":
			asset = filepath.Join(postgresAssetPath, "insertTemperature.sql")
		default:
			tx.Rollback()
			return fmt.Errorf("Measured value type %v not supported", measuredValueType)
		}

		err := insert(tx, asset, measuredValues)
		if err != nil {
			tx.Rollback()
			return err
		}
	}

	return tx.Commit()
}

// InsertSensors into the database
func (postgres *Postgres) InsertSensors(ctx context.Context, sensors ...*types.Sensor) error {
	asset := filepath.Join(postgresAssetPath, "insertSensor.sql")
	queryBytes, err := Asset(asset)
	if err != nil {
		return fmt.Errorf("Failed to load asset %v: %v", asset, err)
	}
	query := string(queryBytes)

	tx, err := postgres.dbo.BeginTx(ctx, &sql.TxOptions{ReadOnly: false})
	if err != nil {
		return fmt.Errorf("Failed to begin new transaction: %v", err)
	}

	stmt, err := tx.Prepare(query)
	if err != nil {
		return fmt.Errorf("Failed to prepare statement: %v", err)
	}
	defer stmt.Close()

	for _, sensor := range sensors {
		_, err = stmt.Exec(&sensor.ID, &sensor.Name, &sensor.Location, &sensor.WireID, &sensor.I2CBus, &sensor.I2CAddress, &sensor.GPIONumber, &sensor.Model, &sensor.Enabled, &sensor.DeviceID, &sensor.CreationDate)
		if err != nil {
			tx.Rollback()
			return fmt.Errorf("Failed to execute statement: %v", err)
		}
	}

	return tx.Commit()
}

// SelectDevice from database
func (postgres *Postgres) SelectDevice(ctx context.Context, id string) (*types.Device, error) {
	asset := filepath.Join(postgresAssetPath, "selectDevice.sql")
	queryBytes, err := Asset(asset)
	if err != nil {
		return nil, fmt.Errorf("Failed to load asset %v: %v", asset, err)
	}
	query := string(queryBytes)

	tx, err := postgres.dbo.BeginTx(ctx, &sql.TxOptions{ReadOnly: true})
	if err != nil {
		return nil, fmt.Errorf("Failed to begin new transaction: %v", err)
	}

	stmt, err := tx.Prepare(query)
	if err != nil {
		return nil, fmt.Errorf("Failed to prepare statement: %v", err)
	}
	defer stmt.Close()

	row := stmt.QueryRow(id)

	device := new(types.Device)
	err = row.Scan(&device.ID, &device.Name, &device.Location, &device.CreationDate)
	if err != nil {
		return nil, fmt.Errorf("Failed to scan row: %v", err)
	}

	err = tx.Commit()
	if err != nil {
		return nil, fmt.Errorf("Failed to commit transaction: %v", err)
	}

	return device, nil
}

// SelectDevices from the database
func (postgres *Postgres) SelectDevices(ctx context.Context) ([]*types.Device, error) {
	asset := filepath.Join(postgresAssetPath, "selectDevices.sql")
	queryBytes, err := Asset(asset)
	if err != nil {
		return nil, fmt.Errorf("Failed to load asset %v: %v", asset, err)
	}
	query := string(queryBytes)

	tx, err := postgres.dbo.BeginTx(ctx, &sql.TxOptions{ReadOnly: true})
	if err != nil {
		return nil, fmt.Errorf("Failed to begin new transaction: %v", err)
	}

	stmt, err := tx.Prepare(query)
	if err != nil {
		return nil, fmt.Errorf("Failed to prepare statement: %v", err)
	}
	defer stmt.Close()

	rows, err := stmt.Query()
	if err != nil {
		return nil, fmt.Errorf("Failed to query statement: %v", err)
	}

	devices := make([]*types.Device, 0)
	for rows.Next() {
		device := new(types.Device)
		err = rows.Scan(&device.ID, &device.Name, &device.Location, &device.CreationDate)
		if err != nil {
			return nil, fmt.Errorf("Failed to scan row: %v", err)
		}
		devices = append(devices, device)
	}

	err = tx.Commit()
	if err != nil {
		return nil, fmt.Errorf("Failed to commit transaction: %v", err)
	}

	return devices, nil
}

// SelectSensor from database
func (postgres *Postgres) SelectSensor(ctx context.Context, id string) (*types.Sensor, error) {
	asset := filepath.Join(postgresAssetPath, "selectSensor.sql")
	queryBytes, err := Asset(asset)
	if err != nil {
		return nil, fmt.Errorf("Failed to load asset %v: %v", asset, err)
	}
	query := string(queryBytes)

	tx, err := postgres.dbo.BeginTx(ctx, &sql.TxOptions{ReadOnly: true})
	if err != nil {
		return nil, fmt.Errorf("Failed to begin new transaction: %v", err)
	}

	stmt, err := tx.Prepare(query)
	if err != nil {
		return nil, fmt.Errorf("Failed to prepare statement: %v", err)
	}
	defer stmt.Close()

	row := stmt.QueryRow(id)

	sensor := new(types.Sensor)
	err = row.Scan(&sensor.ID, &sensor.Name, &sensor.Location, &sensor.WireID, &sensor.I2CBus, &sensor.I2CAddress, &sensor.GPIONumber, &sensor.Model, &sensor.Enabled, &sensor.DeviceID, &sensor.CreationDate)
	if err != nil {
		return nil, fmt.Errorf("Failed to scan row: %v", err)
	}

	err = tx.Commit()
	if err != nil {
		return nil, fmt.Errorf("Failed to commit transaction: %v", err)
	}

	return sensor, nil
}

// SelectSensors from the database
func (postgres *Postgres) SelectSensors(ctx context.Context) ([]*types.Sensor, error) {
	asset := filepath.Join(postgresAssetPath, "selectSensors.sql")
	queryBytes, err := Asset(asset)
	if err != nil {
		return nil, fmt.Errorf("Failed to load asset %v: %v", asset, err)
	}
	query := string(queryBytes)

	tx, err := postgres.dbo.BeginTx(ctx, &sql.TxOptions{ReadOnly: true})
	if err != nil {
		return nil, fmt.Errorf("Failed to begin new transaction: %v", err)
	}

	stmt, err := tx.Prepare(query)
	if err != nil {
		return nil, fmt.Errorf("Failed to prepare statement: %v", err)
	}
	defer stmt.Close()

	rows, err := stmt.Query()
	if err != nil {
		return nil, fmt.Errorf("Failed to query statement: %v", err)
	}

	sensors := make([]*types.Sensor, 0)
	for rows.Next() {
		sensor := new(types.Sensor)
		err = rows.Scan(&sensor.ID, &sensor.Name, &sensor.Location, &sensor.WireID, &sensor.I2CBus, &sensor.I2CAddress, &sensor.GPIONumber, &sensor.Model, &sensor.Enabled, &sensor.DeviceID, &sensor.CreationDate)
		if err != nil {
			return nil, fmt.Errorf("Failed to scan row: %v", err)
		}
		sensors = append(sensors, sensor)
	}

	err = tx.Commit()
	if err != nil {
		return nil, fmt.Errorf("Failed to commit transaction: %v", err)
	}

	return sensors, nil
}

// UpdateDevices updates a device in the database
func (postgres *Postgres) UpdateDevices(ctx context.Context, devices ...*types.Device) error {
	return nil
}

// UpdateSensors updates a sensor in the database
func (postgres *Postgres) UpdateSensors(ctx context.Context, sensor ...*types.Sensor) error {
	return nil
}