package mqtt

import (
	"encoding/json"
	"fmt"
	"log"

	"git.k7n.net/mats/go-telldus/pkg/datastore"
	"git.k7n.net/mats/go-telldus/pkg/telldus"
)

// HADevice represents a device in Home Assistant MQTT discovery
type HADevice struct {
	Identifiers  []string `json:"identifiers"`
	Name         string   `json:"name"`
	Manufacturer string   `json:"manufacturer"`
	Model        string   `json:"model,omitempty"`
}

// SwitchDiscovery represents Home Assistant MQTT switch discovery config
// Reference: https://www.home-assistant.io/integrations/switch.mqtt/
type SwitchDiscovery struct {
	Name              string   `json:"name"`
	CommandTopic      string   `json:"command_topic"`
	StateTopic        string   `json:"state_topic"`
	UniqueID          string   `json:"unique_id"`
	Device            HADevice `json:"device"`
	PayloadOn         string   `json:"payload_on,omitempty"`
	PayloadOff        string   `json:"payload_off,omitempty"`
	StateOn           string   `json:"state_on,omitempty"`
	StateOff          string   `json:"state_off,omitempty"`
	OptimisticMode    bool     `json:"optimistic,omitempty"`
	Qos               int      `json:"qos,omitempty"`
	Retain            bool     `json:"retain,omitempty"`
	AvailabilityTopic string   `json:"availability_topic,omitempty"`
}

// SensorDiscovery represents Home Assistant MQTT sensor discovery config
// Reference: https://www.home-assistant.io/integrations/sensor.mqtt/
type SensorDiscovery struct {
	Name              string   `json:"name"`
	StateTopic        string   `json:"state_topic"`
	UniqueID          string   `json:"unique_id"`
	Device            HADevice `json:"device"`
	UnitOfMeasurement string   `json:"unit_of_measurement,omitempty"`
	DeviceClass       string   `json:"device_class,omitempty"`
	StateClass        string   `json:"state_class,omitempty"`
	ValueTemplate     string   `json:"value_template,omitempty"`
	Qos               int      `json:"qos,omitempty"`
	AvailabilityTopic string   `json:"availability_topic,omitempty"`
}

// PublishAllDiscovery publishes Home Assistant discovery messages for all devices and sensors
func (c *Client) PublishAllDiscovery() error {
	if err := c.publishDeviceDiscovery(); err != nil {
		return err
	}
	if err := c.publishSensorDiscovery(); err != nil {
		return err
	}
	return nil
}

// publishDeviceDiscovery publishes discovery for all devices
func (c *Client) publishDeviceDiscovery() error {
	for device := range c.store.ListDevices() {
		if err := c.PublishDeviceDiscovery(device.ID); err != nil {
			log.Printf("Error publishing discovery for device %d: %v", device.ID, err)
		}
	}
	return nil
}

// PublishDeviceDiscovery publishes Home Assistant discovery for a single device
func (c *Client) PublishDeviceDiscovery(deviceID int) error {
	device, err := c.store.GetDevice(deviceID)
	if err != nil {
		return fmt.Errorf("device %d not found: %w", deviceID, err)
	}

	discovery := SwitchDiscovery{
		Name:         device.Name,
		CommandTopic: fmt.Sprintf("telldus/device/%d/set", deviceID),
		StateTopic:   fmt.Sprintf("telldus/device/%d/state", deviceID),
		UniqueID:     device.UniqueID,
		PayloadOn:    "ON",
		PayloadOff:   "OFF",
		StateOn:      "ON",
		StateOff:     "OFF",
		Device: HADevice{
			Identifiers:  []string{fmt.Sprintf("telldus_%d", deviceID)},
			Name:         device.Name,
			Manufacturer: "Telldus",
			Model:        fmt.Sprintf("%s %s", device.Protocol, device.Model),
		},
	}

	payload, err := json.Marshal(discovery)
	if err != nil {
		return fmt.Errorf("failed to marshal discovery: %w", err)
	}

	topic := fmt.Sprintf("homeassistant/switch/%s/config", device.UniqueID)
	c.client.Publish(topic, 0, true, payload)
	return nil
}

// publishSensorDiscovery publishes discovery for all sensors
func (c *Client) publishSensorDiscovery() error {
	var protocol, model string
	var id, dataTypes int
	ret := telldus.Sensor(&protocol, &model, &id, &dataTypes)

	for ret == 0 {
		sensor, err := c.store.GetSensorByIdentity(protocol, model, id)
		if err != nil || sensor.Hidden {
			log.Printf("Sensor %s %s %d not in DB or hidden, skipping", protocol, model, id)
			ret = telldus.Sensor(&protocol, &model, &id, &dataTypes)
			continue
		}

		if err := c.publishSensorDiscoveryForSensor(sensor, dataTypes); err != nil {
			log.Printf("Error publishing discovery for sensor %s %s %d: %v", protocol, model, id, err)
		}

		ret = telldus.Sensor(&protocol, &model, &id, &dataTypes)
	}
	return nil
}

// PublishSensorDiscovery publishes Home Assistant discovery for a single sensor
func (c *Client) PublishSensorDiscovery(protocol, model string, id int) error {
	sensor, err := c.store.GetSensorByIdentity(protocol, model, id)
	if err != nil {
		return fmt.Errorf("sensor %s %s %d not found: %w", protocol, model, id, err)
	}

	// Get current data types from telldus
	var p, m string
	var sensorID, dataTypes int
	ret := telldus.Sensor(&p, &m, &sensorID, &dataTypes)

	// Find matching sensor
	for ret == 0 {
		if p == protocol && m == model && sensorID == id {
			return c.publishSensorDiscoveryForSensor(sensor, dataTypes)
		}
		ret = telldus.Sensor(&p, &m, &sensorID, &dataTypes)
	}

	return fmt.Errorf("sensor %s %s %d not found in telldus", protocol, model, id)
}

// publishSensorDiscoveryForSensor publishes discovery messages for a sensor's data types
func (c *Client) publishSensorDiscoveryForSensor(sensor *datastore.Sensor, dataTypes int) error {
	sensorDevice := HADevice{
		Identifiers:  []string{fmt.Sprintf("telldus_sensor_%s_%s_%d", sensor.Protocol, sensor.Model, sensor.ID)},
		Name:         sensor.Name,
		Manufacturer: "Telldus",
		Model:        fmt.Sprintf("%s %s", sensor.Protocol, sensor.Model),
	}

	if dataTypes&telldus.DataTypeTemperature != 0 && sensor.TemperatureUniqueID != "" {
		discovery := SensorDiscovery{
			Name:              fmt.Sprintf("%s Temperature", sensor.Name),
			StateTopic:        fmt.Sprintf("telldus/sensor/%s/%s/%d/temperature", sensor.Protocol, sensor.Model, sensor.ID),
			UniqueID:          sensor.TemperatureUniqueID,
			UnitOfMeasurement: "°C",
			DeviceClass:       "temperature",
			StateClass:        "measurement",
			Device:            sensorDevice,
		}

		payload, err := json.Marshal(discovery)
		if err != nil {
			return fmt.Errorf("failed to marshal temperature discovery: %w", err)
		}

		topic := fmt.Sprintf("homeassistant/sensor/%s/config", sensor.TemperatureUniqueID)
		c.client.Publish(topic, 0, true, payload)
	}

	if dataTypes&telldus.DataTypeHumidity != 0 && sensor.HumidityUniqueID != "" {
		discovery := SensorDiscovery{
			Name:              fmt.Sprintf("%s Humidity", sensor.Name),
			StateTopic:        fmt.Sprintf("telldus/sensor/%s/%s/%d/humidity", sensor.Protocol, sensor.Model, sensor.ID),
			UniqueID:          sensor.HumidityUniqueID,
			UnitOfMeasurement: "%",
			DeviceClass:       "humidity",
			StateClass:        "measurement",
			Device:            sensorDevice,
		}

		payload, err := json.Marshal(discovery)
		if err != nil {
			return fmt.Errorf("failed to marshal humidity discovery: %w", err)
		}

		topic := fmt.Sprintf("homeassistant/sensor/%s/config", sensor.HumidityUniqueID)
		c.client.Publish(topic, 0, true, payload)
	}

	return nil
}