// Package miot provides MIoT core client for Xiaomi Home devices.
// mips_client.go — full MIPS (MIoT Pub/Sub) client ported from py-miot/miot_mips.py.
package miot

import (
	"encoding/binary"
	"encoding/json"
	"fmt"
	"math"
	"math/rand"
	"strings"
	"sync"
	"time"

	mqtt "github.com/eclipse/paho.mqtt.golang"

	"xiaomihome/logger"
)

// ============================================================================
// MIPS protocol constants (aligned with Python _MipsClient)
// ============================================================================

const (
	mipsQoS                   = 2
	mipsReconnectIntervalMin  = 10.0  // seconds
	mipsReconnectIntervalMax  = 600.0 // seconds
	mipsSubPatch              = 300
	mipsSubInterval           = 1 // second
	mipsMQTTInterval          = 1 // second
	uint32max                 = 0xFFFFFFFF
	MipsRequestTimeoutDefault = 10000 // milliseconds
)

// ============================================================================
// MIPS message type options (aligned with Python _MipsMsgTypeOptions)
// ============================================================================

const (
	mipsMsgTypeID       = 0
	mipsMsgTypeRetTopic = 1
	mipsMsgTypePayload  = 2
	mipsMsgTypeFrom     = 3
)

// ============================================================================
// MipsMessage — binary message packing/unpacking
// ============================================================================

// MipsMessage represents a packed MIPS protocol message.
// Protocol: each segment is [4-byte length LE][1-byte type][len bytes + 1 null]
type MipsMessage struct {
	Mid      int
	MsgFrom  string
	RetTopic string
	Payload  string
}

// Pack packs a MIPS message into binary format.
// Format: <I (4 bytes len) B (1 byte type)> + data + null terminator
func PackMipsMessage(mid int, payload string, msgFrom, retTopic string) ([]byte, error) {
	if payload == "" {
		return nil, &MIoTMipsError{MIoTError{Code: CodeInvalidParams, Message: "invalid mid or payload"}}
	}

	var buf []byte

	// mid segment
	midBuf := make([]byte, 4)
	binary.LittleEndian.PutUint32(midBuf, uint32(mid))
	buf = append(buf, 0x04, 0x00, 0x00, 0x00) // length = 4
	buf = append(buf, byte(mipsMsgTypeID))
	buf = append(buf, midBuf...)

	// msg_from segment (optional)
	if msgFrom != "" {
		data := []byte(msgFrom)
		seg := buildMipsSegment(mipsMsgTypeFrom, data)
		buf = append(buf, seg...)
	}

	// ret_topic segment (optional)
	if retTopic != "" {
		data := []byte(retTopic)
		seg := buildMipsSegment(mipsMsgTypeRetTopic, data)
		buf = append(buf, seg...)
	}

	// payload segment
	data := []byte(payload)
	seg := buildMipsSegment(mipsMsgTypePayload, data)
	buf = append(buf, seg...)

	return buf, nil
}

// buildMipsSegment builds a single protocol segment.
func buildMipsSegment(msgType int, data []byte) []byte {
	totalLen := len(data) + 1 // +1 for null terminator
	lenBuf := make([]byte, 4)
	binary.LittleEndian.PutUint32(lenBuf, uint32(totalLen))

	var seg []byte
	seg = append(seg, lenBuf...)
	seg = append(seg, byte(msgType))
	seg = append(seg, data...)
	seg = append(seg, 0) // null terminator
	return seg
}

// UnpackMipsMessage unpacks binary data into a MipsMessage.
func UnpackMipsMessage(data []byte) *MipsMessage {
	msg := &MipsMessage{}
	dataLen := len(data)
	pos := 0

	for pos < dataLen {
		if pos+5 > dataLen {
			break
		}
		segLen := int(binary.LittleEndian.Uint32(data[pos : pos+4]))
		segType := int(data[pos+4])
		pos += 5

		if segLen == 0 || pos+segLen > dataLen {
			break
		}
		segData := data[pos : pos+segLen]
		// Strip trailing null
		segData = bytesTrimNull(segData)

		switch segType {
		case mipsMsgTypeID:
			if len(segData) >= 4 {
				msg.Mid = int(binary.LittleEndian.Uint32(segData))
			}
		case mipsMsgTypeRetTopic:
			msg.RetTopic = string(segData)
		case mipsMsgTypePayload:
			msg.Payload = string(segData)
		case mipsMsgTypeFrom:
			msg.MsgFrom = string(segData)
		}
		pos += segLen
	}

	return msg
}

func bytesTrimNull(b []byte) []byte {
	for len(b) > 0 && b[len(b)-1] == 0 {
		b = b[:len(b)-1]
	}
	return b
}

// String returns a debug representation of the message.
func (m *MipsMessage) String() string {
	return fmt.Sprintf("%d, %s, %s, %s", m.Mid, m.MsgFrom, m.RetTopic, m.Payload)
}

// ============================================================================
// MIoTDeviceState — device state enum (aligned with Python MIoTDeviceState)
// ============================================================================

// MIoTDeviceState represents the online/offline state of a device.
type MIoTDeviceState int

const (
	// DeviceStateDisable means the device is disabled.
	DeviceStateDisable MIoTDeviceState = 0
	// DeviceStateOffline means the device is offline.
	DeviceStateOffline MIoTDeviceState = 1
	// DeviceStateOnline means the device is online.
	DeviceStateOnline MIoTDeviceState = 2
)

// String returns the string representation of MIoTDeviceState.
func (s MIoTDeviceState) String() string {
	switch s {
	case DeviceStateDisable:
		return "disable"
	case DeviceStateOffline:
		return "offline"
	case DeviceStateOnline:
		return "online"
	default:
		return "unknown"
	}
}

// ============================================================================
// MipsRequest — pending request tracking
// ============================================================================

// MipsRequest tracks a pending MIPS request with timeout.
type MipsRequest struct {
	Mid        int
	OnReply    func(payload string, ctx interface{})
	OnReplyCtx interface{}
	Timer      *time.Timer
}

// ============================================================================
// MipsBroadcast — subscription tracking
// ============================================================================

// MipsBroadcast represents a subscribed broadcast topic.
type MipsBroadcast struct {
	Topic      string
	Handler    func(topic string, payload string, ctx interface{})
	HandlerCtx interface{}
}

// ============================================================================
// mipsClient — core MIPS client (internal)
// ============================================================================

// mipsClient is the concrete MIPS client using paho MQTT.
type mipsClient struct {
	mu       sync.Mutex
	lgr      logger.Logger
	clientID string
	host     string
	port     int
	username string
	password string
	caFile   string
	certFile string
	keyFile  string

	// MQTT connection
	mqttConn      MQTTClient // interface to paho MQTT
	mqttConnected bool

	// Reconnect
	reconnectActive   bool
	reconnectInterval float64
	reconnectTimer    *time.Timer

	// Subscriptions
	pendingSubs   map[string]int // topic -> retry count
	pendingSubMu  sync.Mutex
	subMu         sync.Mutex
	subscriptions map[string]*MipsBroadcast

	// Requests
	requestMu sync.Mutex
	requests  map[string]*MipsRequest // mid as string -> request
	seedID    int

	// State subscribers
	stateSubMu sync.Mutex
	stateSubs  map[string]func(key string, connected bool)

	// Events
	onConnect    func()
	onDisconnect func(err error)

	// Shutdown
	stopCh chan struct{}
	doneCh chan struct{}
}

// MQTTClient is a small interface for MQTT operations.
// This allows decoupling from the concrete paho MQTT library.
type MQTTClient interface {
	Connect() error
	Disconnect()
	IsConnected() bool
	Subscribe(topic string, qos byte, handler func(topic string, payload []byte)) error
	Unsubscribe(topic string) error
	Publish(topic string, qos byte, payload []byte) error
	SetCredentials(username, password string)
	SetTLS(caFile, certFile, keyFile string) error
}

// newMipsClient creates a new mipsClient (internal).
func newMipsClient(clientID, host string, port int, username, password, caFile, certFile, keyFile string) *mipsClient {
	c := &mipsClient{
		clientID:        clientID,
		host:            host,
		port:            port,
		username:        username,
		password:        password,
		caFile:          caFile,
		certFile:        certFile,
		keyFile:         keyFile,
		lgr:             logger.Default(),
		seedID:          rand.Intn(uint32max),
		pendingSubs:     make(map[string]int),
		subscriptions:   make(map[string]*MipsBroadcast),
		requests:        make(map[string]*MipsRequest),
		stateSubs:       make(map[string]func(key string, connected bool)),
		reconnectActive: true,
		stopCh:          make(chan struct{}),
		doneCh:          make(chan struct{}),
	}
	return c
}

// SetLogger sets a custom logger for mipsClient.
func (c *mipsClient) SetLogger(l logger.Logger) { c.lgr = l }

// connect starts the MQTT connection.
func (c *mipsClient) connect(mqttClient MQTTClient) error {
	c.mu.Lock()
	c.mqttConn = mqttClient
	c.mu.Unlock()

	if err := c.mqttConn.Connect(); err != nil {
		return fmt.Errorf("mqtt connect: %w", err)
	}

	c.mu.Lock()
	c.mqttConnected = true
	c.reconnectActive = true
	c.reconnectInterval = 0
	c.mu.Unlock()

	// Notify connect callbacks
	if c.onConnect != nil {
		c.onConnect()
	}

	// Notify state subscribers
	c.notifyStateSubs(true)

	return nil
}

// disconnect stops the MQTT connection.
func (c *mipsClient) disconnect() {
	c.mu.Lock()
	c.reconnectActive = false
	if c.reconnectTimer != nil {
		c.reconnectTimer.Stop()
		c.reconnectTimer = nil
	}
	c.mu.Unlock()

	if c.mqttConn != nil {
		c.mqttConn.Disconnect()
		c.mu.Lock()
		c.mqttConnected = false
		c.mu.Unlock()

		// Notify disconnect
		if c.onDisconnect != nil {
			c.onDisconnect(nil)
		}
		c.notifyStateSubs(false)
	}
}

// isConnected returns the current connection state.
func (c *mipsClient) isConnected() bool {
	c.mu.Lock()
	defer c.mu.Unlock()
	if c.mqttConn == nil {
		return false
	}
	return c.mqttConn.IsConnected() && c.mqttConnected
}

// subscribe adds a subscription to a topic.
func (c *mipsClient) subscribe(topic string, handler func(topic string, payload string, ctx interface{}), ctx interface{}) error {
	c.subMu.Lock()
	defer c.subMu.Unlock()

	if c.subscriptions[topic] != nil {
		c.lgr.Debugf("[mips] re-register subscription: %s", topic)
	}
	c.subscriptions[topic] = &MipsBroadcast{
		Topic:      topic,
		Handler:    handler,
		HandlerCtx: ctx,
	}

	// Add to pending subs for actual MQTT subscribe
	c.pendingSubMu.Lock()
	c.pendingSubs[topic] = 0
	c.pendingSubMu.Unlock()

	go c.flushPendingSubs()
	return nil
}

// unsubscribe removes a subscription.
func (c *mipsClient) unsubscribe(topic string) error {
	c.subMu.Lock()
	delete(c.subscriptions, topic)
	c.subMu.Unlock()

	if c.mqttConn != nil && c.mqttConn.IsConnected() {
		if err := c.mqttConn.Unsubscribe(topic); err != nil {
			c.lgr.Debugf("[mips] unsubscribe error %s: %v", topic, err)
		}
	}
	return nil
}

// publish sends a message on a topic.
func (c *mipsClient) publish(topic string, payload []byte) error {
	if c.mqttConn == nil || !c.mqttConn.IsConnected() {
		return fmt.Errorf("mips publish when not connected: %s", topic)
	}
	return c.mqttConn.Publish(topic, byte(mipsQoS), payload)
}

// subState subscribes to connection state changes.
func (c *mipsClient) subState(key string, handler func(key string, connected bool)) {
	c.stateSubMu.Lock()
	c.stateSubs[key] = handler
	c.stateSubMu.Unlock()
}

// unsubState unsubscribes from connection state changes.
func (c *mipsClient) unsubState(key string) {
	c.stateSubMu.Lock()
	delete(c.stateSubs, key)
	c.stateSubMu.Unlock()
}

// notifyStateSubs notifies all state subscribers.
func (c *mipsClient) notifyStateSubs(connected bool) {
	c.stateSubMu.Lock()
	subs := make(map[string]func(key string, connected bool), len(c.stateSubs))
	for k, v := range c.stateSubs {
		subs[k] = v
	}
	c.stateSubMu.Unlock()

	for key, handler := range subs {
		if handler != nil {
			handler(key, connected)
		}
	}
}

// onMQTTConnect is called when the MQTT client connects.
func (c *mipsClient) onMQTTConnect() {
	c.mu.Lock()
	c.mqttConnected = true
	c.reconnectInterval = 0 // reset backoff
	c.mu.Unlock()

	// Resubscribe all topics
	c.subMu.Lock()
	topics := make([]string, 0, len(c.subscriptions))
	for topic := range c.subscriptions {
		topics = append(topics, topic)
	}
	c.subMu.Unlock()

	for _, topic := range topics {
		c.pendingSubMu.Lock()
		c.pendingSubs[topic] = 0
		c.pendingSubMu.Unlock()
	}
	go c.flushPendingSubs()
}

// onMQTTDisconnect is called when the MQTT client disconnects.
func (c *mipsClient) onMQTTDisconnect() {
	c.mu.Lock()
	c.mqttConnected = false
	// Clear pending subs
	c.pendingSubMu.Lock()
	c.pendingSubs = make(map[string]int)
	c.pendingSubMu.Unlock()
	c.mu.Unlock()

	// Try reconnect
	c.tryReconnect(false)
}

// onMQTTMessage handles an incoming MQTT message.
func (c *mipsClient) onMQTTMessage(topic string, payload []byte) {
	payloadStr := string(payload)

	// Try exact match first
	c.subMu.Lock()
	bc, ok := c.subscriptions[topic]
	c.subMu.Unlock()

	if ok && bc != nil && bc.Handler != nil {
		bc.Handler(topic, payloadStr, bc.HandlerCtx)
		return
	}

	// Wildcard match: check subscriptions ending with # or +
	for subTopic, bc := range c.copySubs() {
		if bc == nil || bc.Handler == nil {
			continue
		}
		if matchWildcard(subTopic, topic) {
			bc.Handler(topic, payloadStr, bc.HandlerCtx)
		}
	}
}

// copySubs returns a copy of subscriptions for safe wildcard iteration.
func (c *mipsClient) copySubs() map[string]*MipsBroadcast {
	c.subMu.Lock()
	defer c.subMu.Unlock()
	result := make(map[string]*MipsBroadcast, len(c.subscriptions))
	for k, v := range c.subscriptions {
		result[k] = v
	}
	return result
}

// matchWildcard checks if a topic matches a subscription pattern containing # or +.
func matchWildcard(pattern, topic string) bool {
	// Remove trailing /# from pattern and check prefix
	if strings.HasSuffix(pattern, "/#") {
		prefix := strings.TrimSuffix(pattern, "/#")
		return strings.HasPrefix(topic, prefix+"/") || topic == prefix
	}
	return pattern == topic
}

// flushPendingSubs processes pending subscriptions in batches.
// Aligns with Python: __mips_sub_internal_pending_handler.
func (c *mipsClient) flushPendingSubs() {
	if c.mqttConn == nil || !c.mqttConn.IsConnected() {
		return
	}

	c.pendingSubMu.Lock()
	subbed := 0
	for topic, count := range c.pendingSubs {
		if subbed >= mipsSubPatch {
			break
		}
		if count > 3 {
			delete(c.pendingSubs, topic)
			c.lgr.Debugf("[mips] retry sub exceeded: %s", topic)
			continue
		}
		subbed++

		if err := c.mqttConn.Subscribe(topic, byte(mipsQoS), func(t string, p []byte) {
			c.onMQTTMessage(t, p)
		}); err == nil {
			delete(c.pendingSubs, topic)
			c.lgr.Debugf("[mips] sub success: %s", topic)
		} else {
			c.pendingSubs[topic] = count + 1
			c.lgr.Debugf("[mips] retry sub %d: %s %v", count, topic, err)
		}
	}

	hasMore := len(c.pendingSubs) > 0
	c.pendingSubMu.Unlock()

	if hasMore {
		time.Sleep(time.Duration(mipsSubInterval) * time.Second)
		c.flushPendingSubs()
	}
}

// sendRequest sends a MIPS request and waits for a reply.
func (c *mipsClient) sendRequest(topic string, payload string, timeout time.Duration) (string, error) {
	mid := c.nextMid()
	replyCh := make(chan string, 1)

	req := &MipsRequest{
		Mid: mid,
		OnReply: func(payload string, ctx interface{}) {
			select {
			case ctx.(chan string) <- payload:
			default:
			}
		},
		OnReplyCtx: replyCh,
	}

	c.requestMu.Lock()
	c.requests[fmt.Sprintf("%d", mid)] = req
	c.requestMu.Unlock()

	// Build packed message
	packed, err := PackMipsMessage(mid, payload, "", topic)
	if err != nil {
		c.requestMu.Lock()
		delete(c.requests, fmt.Sprintf("%d", mid))
		c.requestMu.Unlock()
		return "", err
	}

	if err := c.publish(topic, packed); err != nil {
		c.requestMu.Lock()
		delete(c.requests, fmt.Sprintf("%d", mid))
		c.requestMu.Unlock()
		return "", err
	}

	// Wait for reply or timeout
	select {
	case reply := <-replyCh:
		return reply, nil
	case <-time.After(timeout):
		c.requestMu.Lock()
		delete(c.requests, fmt.Sprintf("%d", mid))
		c.requestMu.Unlock()
		return `{"error":{"code":-10006,"message":"timeout"}}`, nil
	}
}

// handleReply processes a reply from mips.
func (c *mipsClient) handleReply(mid int, payload string) {
	key := fmt.Sprintf("%d", mid)
	c.requestMu.Lock()
	req, ok := c.requests[key]
	if ok {
		delete(c.requests, key)
	}
	c.requestMu.Unlock()

	if req != nil && req.OnReply != nil {
		req.OnReply(payload, req.OnReplyCtx)
	}
}

// nextMid generates the next MIPS message ID.
func (c *mipsClient) nextMid() int {
	c.mu.Lock()
	mid := c.seedID
	c.seedID = int((c.seedID + 1) % uint32max)
	c.mu.Unlock()
	return mid
}

// tryReconnect schedules a reconnection attempt with exponential backoff.
func (c *mipsClient) tryReconnect(immediate bool) {
	c.mu.Lock()
	if !c.reconnectActive {
		c.mu.Unlock()
		return
	}

	if c.reconnectTimer != nil {
		c.reconnectTimer.Stop()
	}

	var interval time.Duration
	if !immediate {
		if c.reconnectInterval < mipsReconnectIntervalMin {
			c.reconnectInterval = mipsReconnectIntervalMin
		} else {
			c.reconnectInterval = math.Min(c.reconnectInterval*2, mipsReconnectIntervalMax)
		}
		interval = time.Duration(c.reconnectInterval) * time.Second
		c.lgr.Debugf("[mips] reconnect after %v", interval)
	}

	c.reconnectTimer = time.AfterFunc(interval, func() {
		if c.mqttConn != nil {
			if err := c.mqttConn.Connect(); err != nil {
				c.lgr.Debugf("[mips] reconnect failed: %v", err)
				c.tryReconnect(false)
			}
		}
	})
	c.mu.Unlock()
}

// ============================================================================
// MipsCloudClient — cloud MIPS client (public API)
// ============================================================================

// MipsCloudClient wraps the MIPS client for cloud connections.
type MipsCloudClient struct {
	client *mipsClient
	onConn func()
	onDisc func(error)
}

// SubState subscribes to MIPS cloud connection state changes.
// key is a unique subscriber identifier (e.g. "{uid}-{cloudServer}").
func (c *MipsCloudClient) SubState(key string, handler func(key string, connected bool)) {
	c.client.subState(key, handler)
}

// UnsubState unsubscribes from MIPS cloud connection state changes.
func (c *MipsCloudClient) UnsubState(key string) {
	c.client.unsubState(key)
}

// UpdateAccessToken updates the MQTT password (access token) and reconnects.
// Aligns with Python: __update_mips_access_token.
func (c *MipsCloudClient) UpdateAccessToken(accessToken string) {
	c.client.mu.Lock()
	c.client.password = accessToken
	wasConnected := c.client.mqttConnected
	c.client.mu.Unlock()

	if wasConnected {
		c.Disconnect()
		c.Connect()
	}
}

// NewMipsCloudClient creates a new MipsCloudClient.
// broker format: "ssl://cn-ha.mqtt.io.mi.com:8883"
func NewMipsCloudClient(broker, clientID, username, password string) *MipsCloudClient {
	host, port := parseMQTTBroker(broker)
	c := &MipsCloudClient{
		client: newMipsClient(clientID, host, port, username, password, "", "", ""),
	}
	return c
}

// parseMQTTBroker parses a broker URL like "ssl://host:port".
func parseMQTTBroker(broker string) (string, int) {
	// Strip protocol prefix
	url := broker
	if strings.HasPrefix(url, "ssl://") {
		url = url[6:]
	} else if strings.HasPrefix(url, "tcp://") {
		url = url[6:]
	}

	host := url
	port := 8883
	if idx := strings.LastIndex(url, ":"); idx >= 0 {
		host = url[:idx]
		fmt.Sscanf(url[idx+1:], "%d", &port)
	}
	return host, port
}

// Connect connects to the cloud MQTT broker.
func (c *MipsCloudClient) Connect() error {
	mqClient := newPahoMQTTClient(c.client.clientID, c.client.host, c.client.port,
		c.client.username, c.client.password, "", "", "")
	mqClient.onConnect = c.client.onMQTTConnect
	mqClient.onDisconnect = c.client.onMQTTDisconnect
	mqClient.onMessage = c.client.onMQTTMessage

	c.client.onConnect = func() {
		if c.onConn != nil {
			c.onConn()
		}
	}
	c.client.onDisconnect = func(err error) {
		if c.onDisc != nil {
			c.onDisc(err)
		}
	}

	return c.client.connect(mqClient)
}

// Disconnect disconnects from the MQTT broker.
func (c *MipsCloudClient) Disconnect() {
	c.client.disconnect()
}

// IsConnected returns true if connected.
func (c *MipsCloudClient) IsConnected() bool {
	return c.client.isConnected()
}

// Subscribe subscribes to a topic with a handler.
func (c *MipsCloudClient) Subscribe(topic string, handler func(string, []byte)) error {
	return c.client.subscribe(topic, func(_ string, payload string, _ interface{}) {
		handler(topic, []byte(payload))
	}, nil)
}

// Unsubscribe unsubscribes from a topic.
func (c *MipsCloudClient) Unsubscribe(topic string) error {
	return c.client.unsubscribe(topic)
}

// Publish publishes a message to a topic.
func (c *MipsCloudClient) Publish(topic, payload string) error {
	return c.client.publish(topic, []byte(payload))
}

// SubMipsState registers a handler for MIPS state changes.
func (c *MipsCloudClient) SubMipsState(handler func(string, interface{})) {
	c.onConn = func() {
		handler("connected", nil)
	}
	c.onDisc = func(err error) {
		handler("disconnected", err)
	}
}

// GetDevList sends a get_dev_list request through MIPS.
func (c *MipsCloudClient) GetDevList(payload string, timeout time.Duration) (string, error) {
	return c.client.sendRequest("get_dev_list", payload, timeout)
}

// ============================================================================
// MipsLocalClient — local MIPS client (public API)
// ============================================================================

// MipsLocalClient wraps the MIPS client for local connections.
type MipsLocalClient struct {
	client *mipsClient
	did    string
	// GroupID is the home group ID this client belongs to.
	GroupID string
	// OnDevListChanged is called when the gateway's device list changes.
	OnDevListChanged func()
}

// NewMipsLocalClient creates a new MipsLocalClient.
func NewMipsLocalClient(did, host string, port int, caFile, certFile, keyFile string) *MipsLocalClient {
	return &MipsLocalClient{
		client: newMipsClient(did, host, port, "", "", caFile, certFile, keyFile),
		did:    did,
	}
}

// Connect connects to the local MQTT broker.
func (c *MipsLocalClient) Connect() error {
	mqClient := newPahoMQTTClient(c.client.clientID, c.client.host, c.client.port,
		"", "", c.client.caFile, c.client.certFile, c.client.keyFile)
	mqClient.onConnect = c.client.onMQTTConnect
	mqClient.onDisconnect = c.client.onMQTTDisconnect
	mqClient.onMessage = func(topic string, payload []byte) {
		// Try unpacking as MIPS message first
		msg := UnpackMipsMessage(payload)
		if msg != nil && msg.Mid != 0 {
			c.client.handleReply(msg.Mid, msg.Payload)
		}
		// Also pass to generic handler
		c.client.onMQTTMessage(topic, payload)
	}
	return c.client.connect(mqClient)
}

// Disconnect disconnects from the local MQTT broker.
func (c *MipsLocalClient) Disconnect() {
	c.client.disconnect()
}

// IsConnected returns true if connected.
func (c *MipsLocalClient) IsConnected() bool {
	return c.client.isConnected()
}

// Subscribe subscribes to a topic.
func (c *MipsLocalClient) Subscribe(topic string, handler func(string, []byte)) error {
	return c.client.subscribe(topic, func(_ string, payload string, _ interface{}) {
		handler(topic, []byte(payload))
	}, nil)
}

// Unsubscribe unsubscribes from a topic.
func (c *MipsLocalClient) Unsubscribe(topic string) error {
	return c.client.unsubscribe(topic)
}

// GetDevList returns the device list from the gateway.
func (c *MipsLocalClient) GetDevList(payload string, timeout time.Duration) (string, error) {
	return c.client.sendRequest("getDevList", payload, timeout)
}

// GetProps fetches property values from the gateway via MIPS request.
// params is a JSON-encoded string of property parameters.
func (c *MipsLocalClient) GetProps(params []PropParam, timeout time.Duration) ([]PropResult, error) {
	batch := make([]map[string]interface{}, len(params))
	for i, p := range params {
		batch[i] = map[string]interface{}{
			"did":  p.DID,
			"siid": float64(p.Siid),
			"piid": float64(p.Piid),
		}
	}
	payloadBytes, _ := json.Marshal(map[string]interface{}{
		"method": "properties/get",
		"params": batch,
	})
	payload, err := c.client.sendRequest("properties/get", string(payloadBytes), timeout)
	if err != nil {
		return nil, err
	}
	// Parse response
	var result struct {
		Result []PropResult `json:"result"`
	}
	if err := json.Unmarshal([]byte(payload), &result); err != nil {
		return nil, fmt.Errorf("parse gateway props response: %w", err)
	}
	return result.Result, nil
}

// SubState subscribes to MIPS local connection state changes.
func (c *MipsLocalClient) SubState(key string, handler func(key string, connected bool)) {
	c.client.subState(key, handler)
}

// UnsubState unsubscribes from MIPS local connection state changes.
func (c *MipsLocalClient) UnsubState(key string) {
	c.client.unsubState(key)
}

// DID returns the device ID.
func (c *MipsLocalClient) DID() string {
	return c.did
}

// ============================================================================
// MipsDeviceState — device state tracking
// ============================================================================

// MipsDeviceState represents the state of a device's MIPS connection.
type MipsDeviceState struct {
	DID     string
	Online  bool
	Source  string
	Handler func(string, interface{})
}

// NewMipsDeviceState creates a new MipsDeviceState.
func NewMipsDeviceState(did string, online bool, source string) *MipsDeviceState {
	return &MipsDeviceState{
		DID:    did,
		Online: online,
		Source: source,
	}
}

// ============================================================================
// Paho MQTT Client adapter
// ============================================================================

// pahoMQTTClient adapts paho.mqtt.golang to our MQTTClient interface.
type pahoMQTTClient struct {
	clientID string
	host     string
	port     int
	username string
	password string
	caFile   string
	certFile string
	keyFile  string

	lgr logger.Logger

	onConnect    func()
	onDisconnect func()
	onMessage    func(topic string, payload []byte)

	client    mqtt.Client
	connected bool
}

func newPahoMQTTClient(clientID, host string, port int, username, password, caFile, certFile, keyFile string) *pahoMQTTClient {
	c := &pahoMQTTClient{
		clientID: clientID,
		host:     host,
		port:     port,
		username: username,
		password: password,
		caFile:   caFile,
		certFile: certFile,
		keyFile:  keyFile,
		lgr:      logger.Default(),
	}
	return c
}

// SetLogger sets a custom logger for pahoMQTTClient.
func (p *pahoMQTTClient) SetLogger(l logger.Logger) { p.lgr = l }

func (p *pahoMQTTClient) Connect() error {
	opts := mqtt.NewClientOptions()
	opts.AddBroker(fmt.Sprintf("ssl://%s:%d", p.host, p.port))
	opts.SetClientID(p.clientID)
	opts.SetUsername(p.username)
	opts.SetPassword(p.password)
	opts.SetKeepAlive(time.Duration(MIHOME_MQTT_KEEPALIVE) * time.Second)
	opts.SetAutoReconnect(false)
	opts.SetCleanSession(true)

	opts.OnConnect = func(c mqtt.Client) {
		p.lgr.Debugf("[mips] MQTT connected to %s:%d", p.host, p.port)
		p.connected = true
		if p.onConnect != nil {
			p.onConnect()
		}
	}

	opts.OnConnectionLost = func(c mqtt.Client, err error) {
		p.lgr.Debugf("[mips] MQTT connection lost: %v", err)
		p.connected = false
		if p.onDisconnect != nil {
			p.onDisconnect()
		}
	}

	opts.DefaultPublishHandler = func(c mqtt.Client, msg mqtt.Message) {
		p.lgr.Debugf("[mips] MQTT message: %s (%d bytes) data:%s", msg.Topic(), len(msg.Payload()), string(msg.Payload()))
		if p.onMessage != nil {
			p.onMessage(msg.Topic(), msg.Payload())
		}
	}

	p.client = mqtt.NewClient(opts)
	token := p.client.Connect()
	if token.Wait() && token.Error() != nil {
		return token.Error()
	}

	p.lgr.Debugf("[mips] MQTT connected to %s:%d as %s", p.host, p.port, p.clientID)
	return nil
}

func (p *pahoMQTTClient) Disconnect() {
	if p.client != nil && p.client.IsConnected() {
		p.client.Disconnect(250)
	}
	p.connected = false
	if p.onDisconnect != nil {
		p.onDisconnect()
	}
}

func (p *pahoMQTTClient) IsConnected() bool {
	return p.connected
}

func (p *pahoMQTTClient) Subscribe(topic string, qos byte, handler func(topic string, payload []byte)) error {
	if p.client == nil || !p.client.IsConnected() {
		return fmt.Errorf("not connected")
	}

	// Use DefaultPublishHandler for message delivery (set in Connect).
	// Don't set a per-subscription callback to avoid double-firing with DefaultPublishHandler.
	token := p.client.Subscribe(topic, qos, nil)
	if token.Wait() && token.Error() != nil {
		return token.Error()
	}
	return nil
}

func (p *pahoMQTTClient) Unsubscribe(topic string) error {
	if p.client == nil || !p.client.IsConnected() {
		return fmt.Errorf("not connected")
	}

	token := p.client.Unsubscribe(topic)
	if token.Wait() && token.Error() != nil {
		return token.Error()
	}
	p.lgr.Debugf("[mips] unsub success: %s", topic)
	return nil
}

func (p *pahoMQTTClient) Publish(topic string, qos byte, payload []byte) error {
	if p.client == nil || !p.client.IsConnected() {
		return fmt.Errorf("not connected")
	}

	token := p.client.Publish(topic, qos, false, payload)
	if token.Wait() && token.Error() != nil {
		return token.Error()
	}
	return nil
}

func (p *pahoMQTTClient) SetCredentials(username, password string) {
	p.username = username
	p.password = password
}

func (p *pahoMQTTClient) SetTLS(caFile, certFile, keyFile string) error {
	p.caFile = caFile
	p.certFile = certFile
	p.keyFile = keyFile
	return nil
}