package db

import (
	"context"
	"database/sql"
	"fmt"
	"net/url"
	"os"
	"path/filepath"
	"strings"

	"git.cryptic.systems/volker.raschek/flucky/pkg/types"
	"git.cryptic.systems/volker.raschek/go-logger"
)

// Database is a general interface for a database backend like postgres, oracle
// or sqlite
type Database interface {
	Close() error
	DeleteDevices(ctx context.Context, deviceIDs ...string) error
	DeleteSensors(ctx context.Context, sensorIDs ...string) error
	InsertDevices(ctx context.Context, devices ...*types.Device) error
	InsertMeasuredValues(ctx context.Context, measuredValues ...*types.MeasuredValue) error
	InsertSensors(ctx context.Context, sensors ...*types.Sensor) error
	Scheme(ctx context.Context) error
	SelectDevice(ctx context.Context, deviceID string) (*types.Device, error)
	SelectDevices(ctx context.Context) ([]*types.Device, error)
	SelectHumidity(ctx context.Context, id string) (*types.MeasuredValue, error)
	SelectHumidities(ctx context.Context) ([]*types.MeasuredValue, error)
	SelectPressure(ctx context.Context, id string) (*types.MeasuredValue, error)
	SelectPressures(ctx context.Context) ([]*types.MeasuredValue, error)
	SelectSensor(ctx context.Context, sensorID string) (*types.Sensor, error)
	SelectSensors(ctx context.Context) ([]*types.Sensor, error)
	SelectTemperature(ctx context.Context, id string) (*types.MeasuredValue, error)
	SelectTemperatures(ctx context.Context) ([]*types.MeasuredValue, error)
	UpdateDevices(ctx context.Context, devices ...*types.Device) error
	UpdateSensors(ctx context.Context, sensors ...*types.Sensor) error
}

// New returns a new database backend interface
func New(dsnURL *url.URL, flogger logger.Logger) (Database, error) {

	// Check of nil pointer
	for _, parameter := range []interface{}{
		dsnURL,
		flogger,
	} {
		if parameter == nil {
			return nil, fmt.Errorf("Parameter does not be nil")
		}
	}

	// Load Queryfiles
	queries := make(map[string]string, 0)
	for _, asset := range AssetNames() {

		if !strings.Contains(asset, dsnURL.Scheme) {
			continue
		}

		body, err := Asset(asset)
		if err != nil {
			return nil, err
		}

		queryFile := filepath.Base(asset)

		queries[queryFile] = string(body)
	}

	var (
		database Database
		err      error
	)

	switch dsnURL.Scheme {
	case "postgres":

		// postgres://[user]:[password]@[host]:[port]/[path]?[query]
		newDBO, err := sql.Open(dsnURL.Scheme, dsnURL.String())
		if err != nil {
			return nil, err
		}

		database = &Postgres{
			dbo:     newDBO,
			flogger: flogger,
			queries: queries,
		}

	case "sqlite3":

		// Create directory where the db file will be created if not exists.
		if _, err := os.Stat(filepath.Dir(dsnURL.Path)); os.IsNotExist(err) {
			err := os.MkdirAll(filepath.Dir(dsnURL.Path), 0755)
			if err != nil {
				return nil, err
			}
		}

		// sqlite3:///[path]?[query]    flucky dsn
		// file:///[path]?[query]       sql-lib dsn
		newDBO, err := sql.Open(dsnURL.Scheme, fmt.Sprintf("file://%v?%v", dsnURL.Path, dsnURL.RawQuery))
		if err != nil {
			return nil, err
		}

		database = &SQLite{
			dbo:     newDBO,
			flogger: flogger,
			queries: queries,
		}
	default:
		return nil, fmt.Errorf("Unsupported database scheme: %v", dsnURL.Scheme)
	}

	// Initialize database scheme if not exists
	err = database.Scheme(context.Background())
	if err != nil {
		return nil, err
	}

	return database, nil
}