package config

import (
	"context"
	"fmt"
	"os"
	"path/filepath"
	"regexp"

	"time"

	"github.com/volker-raschek/flucky/pkg/internal/format"
	"github.com/volker-raschek/flucky/pkg/storage"

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

var (
	validUUID = regexp.MustCompile("^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$")
)

// Config represent the configuration
type Config struct {
	Device          *types.Device   `json:"device"`
	Sensors         []*types.Sensor `json:"sensors"`
	StorageEndpoint string          `json:"storage_endpoint"`
}

// AddSensor add a new sensor
func (cnf *Config) AddSensor(sensor *types.Sensor) error {

	// Verify that a device is configured
	if cnf.Device == nil {
		return fmt.Errorf("No device configured")
	}

	// Define a new UUID if the current UUID is invalid
	if !validUUID.MatchString(sensor.ID) {
		sensor.ID = uuid.NewV4().String()
	}

	// Verify that the sensor has a valid name
	if len(sensor.Name) <= 0 {
		return fmt.Errorf("No sensor name defined")
	}

	// check if sensor name and sensor uuid already exists
	for _, cnfSensor := range cnf.Sensors {
		if cnfSensor.Name == sensor.Name ||
			cnfSensor.ID == sensor.ID {
			return fmt.Errorf("Sensor with same name or id already exist")
		}

		if cnfSensor.WireID != nil &&
			sensor.WireID != nil &&
			*cnfSensor.WireID == *sensor.WireID {
			return fmt.Errorf("Sensor with same wire id already exist")
		}
	}

	// check if sensor has a valid tick time
	if _, err := time.ParseDuration(sensor.TickDuration); err != nil {
		return fmt.Errorf("Failed to parse tick duration: %v", err)
	}

	// check if sensor has a valid device id
	if sensor.DeviceID != cnf.Device.ID {
		sensor.DeviceID = cnf.Device.ID
	}

	// overwrite creation date
	sensor.CreationDate = format.FormatedTime()

	// check if wire socket is available
	if sensor.WireID != nil {
		socketPath := filepath.Join("/sys/bus/w1/devices", *sensor.WireID, "/w1_slave")
		if _, err := os.Stat(socketPath); os.IsNotExist(err) {
			return fmt.Errorf("Wire socket not found: %v", socketPath)
		}
	}

	cnf.Sensors = append(cnf.Sensors, sensor)

	return nil
}

// DisableSensor disables a sensor by its name or its unique UUID
func (cnf *Config) DisableSensor(name string) error {
	found := false

	for _, sensor := range cnf.Sensors {

		// disable sensor matched after name
		if !validUUID.MatchString(name) &&
			sensor.Name == name {
			sensor.Enabled = false
			found = true
			break
		}

		// remove machted uuid
		if validUUID.MatchString(name) &&
			sensor.ID == name {
			sensor.Enabled = false
			found = true
			break
		}
	}

	if !found {
		return fmt.Errorf("Can not found sensor %v", name)
	}

	return nil
}

// EnableSensor enables a sensor by its name or its unique UUID
func (cnf *Config) EnableSensor(name string) error {
	found := false

	for _, sensor := range cnf.Sensors {

		// disable sensor matched after name
		if !validUUID.MatchString(name) &&
			sensor.Name == name {
			sensor.Enabled = true
			found = true
			break
		}

		// remove machted uuid
		if validUUID.MatchString(name) &&
			sensor.ID == name {
			sensor.Enabled = true
			found = true
			break
		}
	}

	if !found {
		return fmt.Errorf("Can not found sensor %v", name)
	}

	return nil
}

// GetSensorByID returns a sensor matched by his id. If no sensor has this id,
// the function returns nil
func (cnf *Config) GetSensorByID(id string) *types.Sensor {
	for _, sensor := range cnf.Sensors {
		if sensor.ID == id {
			return sensor
		}
	}
	return nil
}

// RemoveSensor deletes a sensor by its name or its unique UUID, If definitive
// is set to true, the sensor will not only be removed in the configuration file
// but also in the backend.
func (cnf *Config) RemoveSensor(name string, definitive bool) error {

	backend, err := storage.New(cnf.StorageEndpoint, nil)
	if err != nil {
		return err
	}

	for i, sensor := range cnf.Sensors {
		// remove machted name
		if !validUUID.MatchString(name) &&
			sensor.Name == name {
			cnf.Sensors = append(cnf.Sensors[:i], cnf.Sensors[i+1:]...)

			if definitive {
				err = backend.RemoveSensorByName(context.Background(), name)
				if err != nil {
					return err
				}
			}

			return nil
		}
		// remove machted uuid
		if validUUID.MatchString(name) &&
			sensor.ID == name {
			cnf.Sensors = append(cnf.Sensors[:i], cnf.Sensors[i+1:]...)

			if definitive {
				err = backend.RemoveSensorByID(context.Background(), name)
				if err != nil {
					return err
				}
			}

			return nil
		}
	}
	return fmt.Errorf("Can not find sensor %v", name)
}

// RenameSensor renamed a sensor
func (cnf *Config) RenameSensor(oldName string, newName string) error {
	for _, cnfSensor := range cnf.Sensors {
		if cnfSensor.Name == oldName {
			cnfSensor.Name = newName
			return nil
		}
	}
	return fmt.Errorf("No sensor %v found", oldName)
}