package db

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

	"github.com/Masterminds/semver"

	"github.com/go-flucky/flucky/pkg/types"
	_ "github.com/lib/pq"
)

type Postgres struct {
	dbo *sql.DB
}

func (p *Postgres) Close() error {
	return p.Close()
}

// Schema create or upgrade database schema to the version of the flucky binary
func (p *Postgres) Schema(ctx context.Context, version *semver.Version) error {

	query := "SELECT value FROM info WHERE key='version';"

	stmt, err := p.dbo.PrepareContext(ctx, query)
	if err != nil {

		asset := "pkg/db/sql/psql/schema.sql"
		queryBytes, err := Asset(asset)
		if err != nil {
			return fmt.Errorf("%v: %v", errorGetAsset, err)
		}
		query = string(queryBytes)

		_, err = p.dbo.ExecContext(ctx, query)
		if err != nil {
			return fmt.Errorf("%v: %v", errorStatementExecute, err)
		}

		return nil
	}

	schemaVersion := ""
	row := stmt.QueryRowContext(ctx)
	err = row.Scan(&schemaVersion)
	if err != nil {
		return fmt.Errorf("%v: %v", errorScanRow, err)
	}

	fromVersion, err := semver.NewVersion(schemaVersion)
	if err != nil {
		return fmt.Errorf("Can not create new sematic version from database: %v", err)
	}

	if err := schema(fromVersion, version); err != nil {
		return err
	}

	// The result will be 0 if from == to, -1 if from < to, or +1 if from > to.
	switch fromVersion.Compare(version) {
	case -1:
		return schema(fromVersion, version)
	case 0:
		// fromVersion and toVersion are equal
		return nil
	case 1:
		// fromVersion < toVersion
		return fmt.Errorf("Can not downgrade the database schema. Update the flucky binary")
	}

	return nil

}

func (p *Postgres) DeleteDevices(ctx context.Context, devices []*types.Device) error {
	asset := "pkg/db/sql/psql/deleteDevice.sql"
	queryBytes, err := Asset(asset)
	if err != nil {
		return fmt.Errorf("%v: %v", errorGetAsset, err)
	}
	query := string(queryBytes)

	stmt, err := p.dbo.PrepareContext(ctx, query)
	if err != nil {
		return fmt.Errorf("%v: %v", errorPrepareStatement, err)
	}
	defer stmt.Close()

	for _, device := range devices {
		_, err := stmt.ExecContext(ctx, &device.DeviceID)
		if err != nil {
			return fmt.Errorf("%v: %v", errorStatementExecute, err)
		}
	}

	return nil
}

func (p *Postgres) DeleteSensors(ctx context.Context, sensors []*types.Sensor) error {
	asset := "pkg/db/sql/psql/deleteSensor.sql"
	queryBytes, err := Asset(asset)
	if err != nil {
		return fmt.Errorf("%v: %v", errorGetAsset, err)
	}
	query := string(queryBytes)

	stmt, err := p.dbo.PrepareContext(ctx, query)
	if err != nil {
		return fmt.Errorf("%v: %v", errorPrepareStatement, err)
	}
	defer stmt.Close()

	for _, sensor := range sensors {
		_, err := stmt.ExecContext(ctx, &sensor.SensorID)
		if err != nil {
			return fmt.Errorf("%v: %v", errorStatementExecute, err)
		}
	}

	return nil
}

func (p *Postgres) DeleteMeasuredValues(ctx context.Context, measuredValues []*types.MeasuredValue) error {

	deleteMeasuredValue := func(ctx context.Context, query string, measuredValues []*types.MeasuredValue) error {
		stmt, err := p.dbo.PrepareContext(ctx, query)
		if err != nil {
			return fmt.Errorf("%v: %v", errorPrepareStatement, err)
		}
		defer stmt.Close()

		for _, measuredValue := range measuredValues {
			_, err := stmt.ExecContext(ctx, &measuredValue.ID)
			if err != nil {
				return fmt.Errorf("%v: %v", errorStatementExecute, err)
			}
		}
		return nil
	}

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

	assetFunc := func(queryFile string) (string, error) {
		queryBytes, err := Asset(queryFile)
		if err != nil {
			return "", fmt.Errorf("%v: %v", errorGetAsset, err)
		}
		return string(queryBytes), nil
	}

	for measuredValueType, sortedMeasuredValues := range sortedMeasuredValueTypes {
		switch measuredValueType {
		case types.MeasuredValueTypeHumidity:
			query, err := assetFunc("pkg/db/sql/psql/deleteHumidity.sql")
			if err != nil {
				return err
			}

			if err := deleteMeasuredValue(ctx, query, sortedMeasuredValues); err != nil {
				return err
			}
		case types.MeasuredValueTypePressure:
			query, err := assetFunc("pkg/db/sql/psql/deletePressure.sql")
			if err != nil {
				return err
			}

			if err := deleteMeasuredValue(ctx, query, sortedMeasuredValues); err != nil {
				return err
			}
		case types.MeasuredValueTypeTemperature:
			query, err := assetFunc("pkg/db/sql/psql/deleteTemperature.sql")
			if err != nil {
				return err
			}

			if err := deleteMeasuredValue(ctx, query, sortedMeasuredValues); err != nil {
				return err
			}
		}
	}

	return nil
}

func (p *Postgres) InsertDevices(ctx context.Context, devices []*types.Device) error {
	asset := "pkg/db/sql/psql/insertDevice.sql"
	queryBytes, err := Asset(asset)
	if err != nil {
		return fmt.Errorf("%v: %v", errorGetAsset, err)
	}
	query := string(queryBytes)

	stmt, err := p.dbo.PrepareContext(ctx, query)
	if err != nil {
		return fmt.Errorf("%v: %v", errorPrepareStatement, err)
	}
	defer stmt.Close()

	for _, device := range devices {
		_, err := stmt.ExecContext(ctx, &device.DeviceID, &device.DeviceName, &device.DeviceLocation, &device.CreationDate)
		if err != nil {
			return fmt.Errorf("%v: %v", errorStatementExecute, err)
		}
	}

	return nil
}

func (p *Postgres) InsertMeasuredValues(ctx context.Context, measuredValues []*types.MeasuredValue) error {

	sortedMeasuredValueTypes := make(map[types.MeasuredValueType][]*types.MeasuredValue)

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

	for measuredValueType, sortedMeasuredValues := range sortedMeasuredValueTypes {
		switch measuredValueType {
		case types.MeasuredValueTypeHumidity:
			if err := p.insertHumidity(ctx, sortedMeasuredValues); err != nil {
				return err
			}
		case types.MeasuredValueTypePressure:
			if err := p.insertPressure(ctx, sortedMeasuredValues); err != nil {
				return err
			}
		case types.MeasuredValueTypeTemperature:
			if err := p.insertTemperature(ctx, sortedMeasuredValues); err != nil {
				return err
			}
		}
	}

	return nil
}

func (p *Postgres) insertHumidity(ctx context.Context, measuredValues []*types.MeasuredValue) error {

	asset := "pkg/db/sql/psql/insertHumidity.sql"
	queryBytes, err := Asset(asset)
	if err != nil {
		return fmt.Errorf("%v: %v", errorGetAsset, err)
	}
	query := string(queryBytes)

	stmt, err := p.dbo.PrepareContext(ctx, query)
	if err != nil {
		return fmt.Errorf("%v: %v", errorPrepareStatement, err)
	}
	defer stmt.Close()

	for _, measuredValue := range measuredValues {

		if measuredValue.ValueType != types.MeasuredValueTypeHumidity {
			continue
		}

		_, err := stmt.ExecContext(ctx, &measuredValue.ID, &measuredValue.Value, &measuredValue.FromDate, &measuredValue.TillDate, &measuredValue.SensorID, &measuredValue.CreationDate, &measuredValue.UpdateDate)
		if err != nil {
			return fmt.Errorf("%v: %v", errorStatementExecute, err)
		}
	}
	return nil
}

func (p *Postgres) insertPressure(ctx context.Context, measuredValues []*types.MeasuredValue) error {

	asset := "pkg/db/sql/psql/insertPressure.sql"
	queryBytes, err := Asset(asset)
	if err != nil {
		return fmt.Errorf("%v: %v", errorGetAsset, err)
	}
	query := string(queryBytes)

	stmt, err := p.dbo.PrepareContext(ctx, query)
	if err != nil {
		return fmt.Errorf("%v: %v", errorPrepareStatement, err)
	}
	defer stmt.Close()

	for _, measuredValue := range measuredValues {

		if measuredValue.ValueType != types.MeasuredValueTypePressure {
			continue
		}

		_, err := stmt.ExecContext(ctx, &measuredValue.ID, &measuredValue.Value, &measuredValue.FromDate, &measuredValue.TillDate, &measuredValue.SensorID, &measuredValue.CreationDate, &measuredValue.UpdateDate)
		if err != nil {
			return fmt.Errorf("%v: %v", errorStatementExecute, err)
		}
	}
	return nil
}

func (p *Postgres) insertTemperature(ctx context.Context, measuredValues []*types.MeasuredValue) error {

	asset := "pkg/db/sql/psql/insertTemperature.sql"
	queryBytes, err := Asset(asset)
	if err != nil {
		return fmt.Errorf("%v: %v", errorGetAsset, err)
	}
	query := string(queryBytes)

	stmt, err := p.dbo.PrepareContext(ctx, query)
	if err != nil {
		return fmt.Errorf("%v: %v", errorPrepareStatement, err)
	}
	defer stmt.Close()

	for _, measuredValue := range measuredValues {

		if measuredValue.ValueType != types.MeasuredValueTypeTemperature {
			continue
		}

		_, err := stmt.ExecContext(ctx, &measuredValue.ID, &measuredValue.Value, &measuredValue.FromDate, &measuredValue.TillDate, &measuredValue.SensorID, &measuredValue.CreationDate, &measuredValue.UpdateDate)
		if err != nil {
			return fmt.Errorf("%v: %v", errorStatementExecute, err)
		}
	}
	return nil
}

func (p *Postgres) InsertSensors(ctx context.Context, sensors []*types.Sensor) error {

	asset := "pkg/db/sql/psql/insertSensor.sql"
	queryBytes, err := Asset(asset)
	if err != nil {
		return fmt.Errorf("%v: %v", errorGetAsset, err)
	}
	query := string(queryBytes)

	stmt, err := p.dbo.PrepareContext(ctx, query)
	if err != nil {
		return fmt.Errorf("%v: %v", errorPrepareStatement, err)
	}
	defer stmt.Close()

	for _, sensor := range sensors {

		_, err := stmt.ExecContext(ctx, &sensor.SensorID, &sensor.SensorName, &sensor.SensorLocation, &sensor.WireID, &sensor.I2CBus, &sensor.I2CAddress, &sensor.GPIONumber, &sensor.SensorModel, &sensor.SensorEnabled, &sensor.DeviceID, &sensor.CreationDate)
		if err != nil {
			return fmt.Errorf("%v: %v", errorStatementExecute, err)
		}
	}
	return nil
}

func (p *Postgres) SelectDeviceByID(ctx context.Context, id string) (*types.Device, error) {
	asset := "pkg/db/sql/psql/selectDeviceByID.sql"
	queryBytes, err := Asset(asset)
	if err != nil {
		return nil, fmt.Errorf("%v: %v", errorGetAsset, err)
	}
	query := string(queryBytes)

	stmt, err := p.dbo.PrepareContext(ctx, query)
	if err != nil {
		return nil, fmt.Errorf("%v: %v", errorPrepareStatement, err)
	}

	row := stmt.QueryRowContext(ctx, id)
	if row == nil {
		return nil, errorRowNotFound
	}

	device := new(types.Device)
	err = row.Scan(&device.DeviceID, &device.DeviceName, &device.DeviceLocation, &device.CreationDate)
	if err != nil {
		return nil, fmt.Errorf("%v: %v", errorScanRow, err)
	}

	return device, nil
}

func (p *Postgres) SelectMeasuredValuesByIDAndType(ctx context.Context, id string, valueType types.MeasuredValueType) (*types.MeasuredValue, error) {
	switch valueType {
	case types.MeasuredValueTypeHumidity:
		return p.SelectHumidityByID(ctx, id)
	case types.MeasuredValueTypePressure:
		return p.SelectPressureByID(ctx, id)
	case types.MeasuredValueTypeTemperature:
		return p.SelectTemperatureByID(ctx, id)
	default:
		return nil, fmt.Errorf("%v: %v", errorUnknownMeasuredValueType, valueType)
	}
}

func (p *Postgres) SelectHumidities(ctx context.Context) ([]*types.MeasuredValue, error) {
	queryFile := "pkg/db/sql/psql/selectHumidities.sql"
	measuredValues, err := p.selectMeasuredValues(ctx, types.MeasuredValueTypeHumidity, queryFile, nil)
	if err != nil {
		return nil, err
	}
	return measuredValues, nil
}

func (p *Postgres) SelectHumidityByID(ctx context.Context, id string) (*types.MeasuredValue, error) {
	queryFile := "pkg/db/sql/psql/selectHumidityByID.sql"
	args := []interface{}{id}
	measuredValues, err := p.selectMeasuredValues(ctx, types.MeasuredValueTypeHumidity, queryFile, args)
	if err != nil {
		return nil, err
	}

	if len(measuredValues) == 0 {
		return nil, fmt.Errorf("%v: %v", errorRowNotFound, id)
	}

	return measuredValues[0], nil
}

func (p *Postgres) SelectPressures(ctx context.Context) ([]*types.MeasuredValue, error) {
	queryFile := "pkg/db/sql/psql/selectPressures.sql"
	measuredValues, err := p.selectMeasuredValues(ctx, types.MeasuredValueTypePressure, queryFile, nil)
	if err != nil {
		return nil, err
	}
	return measuredValues, nil
}

func (p *Postgres) SelectPressureByID(ctx context.Context, id string) (*types.MeasuredValue, error) {
	queryFile := "pkg/db/sql/psql/selectPressureByID.sql"
	args := []interface{}{id}
	measuredValues, err := p.selectMeasuredValues(ctx, types.MeasuredValueTypePressure, queryFile, args)
	if err != nil {
		return nil, err
	}

	if len(measuredValues) == 0 {
		return nil, fmt.Errorf("%v: %v", errorRowNotFound, id)
	}

	return measuredValues[0], nil
}

func (p *Postgres) SelectSensorByID(ctx context.Context, id string) (*types.Sensor, error) {
	asset := "pkg/db/sql/psql/selectSensorByID.sql"
	queryBytes, err := Asset(asset)
	if err != nil {
		return nil, fmt.Errorf("%v: %v", errorGetAsset, err)
	}
	query := string(queryBytes)

	stmt, err := p.dbo.PrepareContext(ctx, query)
	if err != nil {
		return nil, fmt.Errorf("%v: %v", errorPrepareStatement, err)
	}

	row := stmt.QueryRowContext(ctx, id)
	if row == nil {
		return nil, errorRowNotFound
	}

	sensor := new(types.Sensor)
	err = row.Scan(&sensor.SensorID, &sensor.SensorName, &sensor.SensorLocation, &sensor.WireID, &sensor.I2CBus, &sensor.I2CAddress, &sensor.GPIONumber, &sensor.SensorModel, &sensor.SensorEnabled, &sensor.DeviceID, &sensor.CreationDate)
	if err != nil {
		return nil, fmt.Errorf("%v: %v", errorScanRow, err)
	}

	return sensor, nil
}

func (p *Postgres) SelectTemperatures(ctx context.Context) ([]*types.MeasuredValue, error) {
	queryFile := "pkg/db/sql/psql/selectTemperatures.sql"
	measuredValues, err := p.selectMeasuredValues(ctx, types.MeasuredValueTypeTemperature, queryFile, nil)
	if err != nil {
		return nil, err
	}
	return measuredValues, nil
}

func (p *Postgres) SelectTemperatureByID(ctx context.Context, id string) (*types.MeasuredValue, error) {
	queryFile := "pkg/db/sql/psql/selectTemperatureByID.sql"
	args := []interface{}{id}
	measuredValues, err := p.selectMeasuredValues(ctx, types.MeasuredValueTypeTemperature, queryFile, args)
	if err != nil {
		return nil, err
	}

	if len(measuredValues) == 0 {
		return nil, fmt.Errorf("%v: %v", errorRowNotFound, id)
	}

	return measuredValues[0], nil
}

func (p *Postgres) selectMeasuredValues(ctx context.Context, measuredValueType types.MeasuredValueType, queryFile string, queryArgs []interface{}) ([]*types.MeasuredValue, error) {
	queryBytes, err := Asset(queryFile)
	if err != nil {
		return nil, fmt.Errorf("%v: %v", errorGetAsset, err)
	}
	query := string(queryBytes)

	stmt, err := p.dbo.PrepareContext(ctx, query)
	if err != nil {
		return nil, fmt.Errorf("%v: %v", errorPrepareStatement, err)
	}

	rows, err := stmt.QueryContext(ctx, queryArgs...)
	if err != nil {
		return nil, fmt.Errorf("%v: %v", errorStatementQuery, err)
	}

	measuredValues := make([]*types.MeasuredValue, 0)
	for rows.Next() {
		measuredValue := new(types.MeasuredValue)
		measuredValue.ValueType = measuredValueType
		rows.Scan(&measuredValue.ID, &measuredValue.Value, &measuredValue.FromDate, &measuredValue.TillDate, &measuredValue.SensorID, &measuredValue.CreationDate, &measuredValue.UpdateDate)
		measuredValues = append(measuredValues, measuredValue)
	}

	return measuredValues, nil
}

func (p *Postgres) UpdateDevices(ctx context.Context, devices []*types.Device) error {
	return nil
}

func (p *Postgres) UpdateMeasuredValues(ctx context.Context, measuredValues []*types.MeasuredValue) error {
	return nil
}

func (p *Postgres) UpdateSensors(ctx context.Context, sensots []*types.Sensor) error {
	return nil
}

func schema(fromVersion *semver.Version, toVersion *semver.Version) error {

	sqlAssetFiles, err := parseAssetDir("pkg/db/sql/psql/schema")
	if err != nil {
		return fmt.Errorf("Can not restore sql files: %v", err)
	}

	for _, sqlAssetFile := range sqlAssetFiles {

    version := strings.Replace()

		sqlSchemaInformations := &schemaInformation{
			Version: filepath.Split()
			Asset:   sqlAssetFile,
		}

	}

	return nil
}

func parseAssetDir(dir string) ([]string, error) {
	assetFiles, err := AssetDir(dir)
	if err != nil {
		return nil, fmt.Errorf("Can not load asset directory %v: %v", dir, err)
	}

	goldenAssetFiles := assetFiles

	for i, assetFile := range assetFiles {
		if strings.HasPrefix(assetFile, "/") {
			// is directory- SKIP
			goldenAssetFiles = append(goldenAssetFiles[:i], goldenAssetFiles[i+1:]...)
		}
	}

	return goldenAssetFiles, nil
}