// Package miot provides MIoT core client for Xiaomi Home devices.
// It's a Golang port of MIoTClient from xiaomihome-py/miot/.
package miot

import (
	"encoding/json"
	"fmt"
)

// ============================================================================
// Subscription management (aligned with Python miot_client.py)
// ============================================================================

// SubProp subscribes to device property changes.
// Aligns with Python: sub_prop method.
// did: device ID
// handler: callback function called when property changes
// siid, piid: property identifiers
// Returns: subscription ID for unsubscribing.
func (c *MIoTClient) SubProp(did string, handler func(map[string]interface{}, interface{}), siid, piid int) string {
	c.mu.Lock()

	// Build topic with wildcard for 0 values
	topic := buildPropTopic(did, siid, piid)
	subID := fmt.Sprintf("%p", handler)
	c.subTree.Sub(topic, handler, nil)

	c.lgr.Debugf("[MIoTClient] Subscribed to property: %s (topic=%s, subID=%s)\n", did, topic, subID)

	c.mu.Unlock()

	// siid=0 && piid=0 为通配符订阅，展开为设备所有可读属性逐条刷新
	if siid == 0 && piid == 0 {
		c.RefreshDeviceAllProps(did)
	} else {
		c.RequestRefreshProp(did, siid, piid)
	}

	return subID
}

// UnsubProp unsubscribes from device property changes.
// Aligns with Python: unsub_prop method.
func (c *MIoTClient) UnsubProp(did string, subID string) {
	c.mu.Lock()
	defer c.mu.Unlock()

	// Remove from subTree by subID
	c.subTree.Unsub(subID)

	// Check if there are any remaining subscriptions for this device
	// TODO: Implement proper tracking of per-device subscription count
	// For now, just log

	c.lgr.Debugf("[MIoTClient] Unsubscribed from property: %s (subID=%s)\n", did, subID)
}

// SubEvent subscribes to device events.
// Aligns with Python: sub_event method.
// did: device ID
// handler: callback function called when event occurs
// siid, eiid: event identifiers
// Returns: subscription ID for unsubscribing.
func (c *MIoTClient) SubEvent(did string, handler func(map[string]interface{}, interface{}), siid, eiid int) string {
	c.mu.Lock()
	defer c.mu.Unlock()

	topic := buildEventTopic(did, siid, eiid)
	subID := fmt.Sprintf("%p", handler)
	c.subTree.Sub(topic, handler, nil)

	c.lgr.Debugf("[MIoTClient] Subscribed to event: %s (topic=%s, subID=%s)\n", did, topic, subID)

	return subID
}

// UnsubEvent unsubscribes from device events.
// Aligns with Python: unsub_event method.
func (c *MIoTClient) UnsubEvent(did string, subID string) {
	c.mu.Lock()
	defer c.mu.Unlock()

	// Remove from subTree by subID
	c.subTree.Unsub(subID)

	c.lgr.Debugf("[MIoTClient] Unsubscribed from event: %s (subID=%s)\n", did, subID)
}

// updateDeviceMsgSub updates device message subscription.
// Aligns with Python: __update_device_msg_sub.
// Determines the best subscription source (gateway > LAN > cloud) and switches if needed.
func (c *MIoTClient) updateDeviceMsgSub(did string) {
	c.mu.Lock()
	defer c.mu.Unlock()

	// Read device state from three sources
	cloudOnline := false
	gwOnline := false
	gwPushAvailable := false
	lanOnline := false
	lanPushAvailable := false
	gwGroupID := ""

	if dev, ok := c.deviceListCloud[did]; ok {
		if o, ok := dev["online"].(bool); ok {
			cloudOnline = o
		}
	}
	if dev, ok := c.deviceListGateway[did]; ok {
		if o, ok := dev["online"].(bool); ok {
			gwOnline = o
		}
		if p, ok := dev["push_available"].(bool); ok {
			gwPushAvailable = p
		}
		gwGroupID, _ = dev["group_id"].(string)
	}
	if dev, ok := c.deviceListLan[did]; ok {
		if o, ok := dev["online"].(bool); ok {
			lanOnline = o
		}
		if p, ok := dev["push_available"].(bool); ok {
			lanPushAvailable = p
		}
	}

	// Priority: gateway(online+push_available) > LAN(online+push_available) > cloud(online)
	newSource := "none"
	if gwOnline && gwPushAvailable {
		newSource = gwGroupID // gateway source = groupID
	} else if lanOnline && lanPushAvailable {
		newSource = "lan"
	} else if cloudOnline {
		newSource = "cloud"
	}

	oldSource, existed := c.subSourceList[did]
	if !existed {
		oldSource = "none"
	}

	// No change
	if oldSource == newSource {
		return
	}

	// Source changed: unsubscribe from old, subscribe to new
	if oldSource != "none" {
		c.unsubFromSource(oldSource, did)
	}
	if newSource != "none" {
		c.subFromSource(newSource, did)
	}

	// Update subscription source
	c.subSourceList[did] = newSource

	c.lgr.Infof("[MIoTClient] updateDeviceMsgSub: %s source %s → %s (gw=%v/%v, lan=%v/%v, cloud=%v)\n",
		did, oldSource, newSource, gwOnline, gwPushAvailable, lanOnline, lanPushAvailable, cloudOnline)
}

// unsubFromSource unsubscribes device messages from a given source.
func (c *MIoTClient) unsubFromSource(source, did string) {
	switch source {
	case "cloud":
		if c.mipsCloud != nil {
			c.mipsCloud.Unsubscribe(fmt.Sprintf("device/%s/up/properties_changed/#", did))
			c.mipsCloud.Unsubscribe(fmt.Sprintf("device/%s/up/event_occured/#", did))
			c.mipsCloud.Unsubscribe(fmt.Sprintf("device/%s/state/#", did))
		}
	case "lan":
		if c.miotLan != nil {
			lan, ok := c.miotLan.(*MIoTLan)
			if ok {
				lan.UnsubProp(did, 0, 0)
				lan.UnsubEvent(did, 0, 0)
			}
		}
	default:
		// Gateway: source is the groupID
		if mips, exists := c.mipsLocal[source]; exists {
			mips.Unsubscribe(fmt.Sprintf("device/%s/up/properties_changed/#", did))
			mips.Unsubscribe(fmt.Sprintf("device/%s/up/event_occured/#", did))
			mips.Unsubscribe(fmt.Sprintf("device/%s/state/#", did))
		}
	}
}

// subFromSource subscribes device messages from a given source.
func (c *MIoTClient) subFromSource(source, did string) {
	switch source {
	case "cloud":
		if c.mipsCloud != nil {
			c.subscribeDeviceMessages(c.mipsCloud, did)
		}
	case "lan":
		if c.miotLan != nil {
			lan, ok := c.miotLan.(*MIoTLan)
			if ok {
				lan.SubProp(did, nil, 0, 0, nil)
				lan.SubEvent(did, nil, 0, 0, nil)
			}
		}
	default:
		// Gateway: source is the groupID
		if mips, exists := c.mipsLocal[source]; exists {
			c.subscribeDeviceMessagesOnLocal(mips, did)
		}
	}
}

// subscribeDeviceMessagesOnLocal subscribes to device messages from a local MIPS client.
func (c *MIoTClient) subscribeDeviceMessagesOnLocal(client *MipsLocalClient, did string) {
	propTopic := fmt.Sprintf("device/%s/up/properties_changed/#", did)
	client.Subscribe(propTopic, func(topic string, payload []byte) {
		c.handleMIPSMessage(did, payload)
	})

	eventTopic := fmt.Sprintf("device/%s/up/event_occured/#", did)
	client.Subscribe(eventTopic, func(topic string, payload []byte) {
		c.handleMIPSMessage(did, payload)
	})

	stateTopic := fmt.Sprintf("device/%s/state/#", did)
	client.Subscribe(stateTopic, func(topic string, payload []byte) {
		c.handleMIPSStateMessage(did, payload)
	})
}

// subscribeDeviceMessages subscribes to device property/event/state messages.
func (c *MIoTClient) subscribeDeviceMessages(client *MipsCloudClient, did string) {
	// Subscribe to property changes
	propTopic := fmt.Sprintf("device/%s/up/properties_changed/#", did)
	client.Subscribe(propTopic, func(topic string, payload []byte) {
		c.handleMIPSMessage(did, payload)
	})

	// Subscribe to events
	eventTopic := fmt.Sprintf("device/%s/up/event_occured/#", did)
	client.Subscribe(eventTopic, func(topic string, payload []byte) {
		c.handleMIPSMessage(did, payload)
	})

	// Subscribe to state changes
	stateTopic := fmt.Sprintf("device/%s/state/#", did)
	client.Subscribe(stateTopic, func(topic string, payload []byte) {
		c.handleMIPSStateMessage(did, payload)
	})
}

// handleMIPSMessage handles MIPS property/event messages.
func (c *MIoTClient) handleMIPSMessage(did string, payload []byte) {
	// First try: direct JSON (cloud MIPS push messages are plain JSON)
	var params map[string]interface{}
	if err := json.Unmarshal(payload, &params); err == nil && len(params) > 0 {
		c.dispatchMIPSMessage(did, params)
		return
	}

	// Fallback: binary MIPS protocol (used by gateway mipsLocal)
	msg := UnpackMipsMessage(payload)
	if msg == nil || msg.Payload == "" {
		c.lgr.Debugf("[MIoTClient] handleMIPSMessage: empty or invalid payload for %s (%d bytes)\n", did, len(payload))
		return
	}

	// Parse JSON from unpacked payload
	if err := json.Unmarshal([]byte(msg.Payload), &params); err != nil {
		c.lgr.Errorf("[MIoTClient] handleMIPSMessage: JSON parse error for %s: %v\n", did, err)
		return
	}

	c.dispatchMIPSMessage(did, params)
}

// dispatchMIPSMessage dispatches parsed MIPS params to OnPropMsg or OnEventMsg.
func (c *MIoTClient) dispatchMIPSMessage(did string, params map[string]interface{}) {
	// Determine if it's a property or event message
	if inner, ok := params["params"].(map[string]interface{}); ok {
		// Cloud MIPS format: {"params": {"did":"...", "siid":..., "piid":..., "value":...}}
		if _, hasEiid := inner["eiid"]; hasEiid {
			c.OnEventMsg(params, nil)
		} else {
			c.OnPropMsg(params, nil)
		}
	} else if _, ok := params["siid"]; ok {
		// Direct format: {"did":"...", "siid":..., "piid":..., "value":...}
		c.OnPropMsg(params, nil)
	} else if _, ok := params["eiid"]; ok {
		c.OnEventMsg(params, nil)
	} else {
		c.lgr.Debugf("[MIoTClient] handleMIPSMessage: unknown message format for %s: %v\n", did, params)
	}
}

// handleMIPSStateMessage handles MIPS state messages (online/offline).
func (c *MIoTClient) handleMIPSStateMessage(did string, payload []byte) {
	// First try: direct JSON
	var params map[string]interface{}
	if err := json.Unmarshal(payload, &params); err != nil || len(params) == 0 {
		// Fallback: binary MIPS protocol
		msg := UnpackMipsMessage(payload)
		if msg == nil || msg.Payload == "" {
			c.lgr.Debugf("[MIoTClient] handleMIPSStateMessage: empty payload for %s (%d bytes)\n", did, len(payload))
			return
		}
		if err := json.Unmarshal([]byte(msg.Payload), &params); err != nil {
			c.lgr.Errorf("[MIoTClient] handleMIPSStateMessage: JSON parse error for %s: %v\n", did, err)
			return
		}
	}

	// Extract state fields
	state := make(map[string]interface{})

	// Online/offline from typical state formats
	if online, ok := params["online"].(bool); ok {
		state["online"] = online
	} else if status, ok := params["status"].(string); ok {
		state["online"] = status == "online"
	}

	// Push availability
	if push, ok := params["push_available"].(bool); ok {
		state["push_available"] = push
	}

	if len(state) == 0 {
		c.lgr.Debugf("[MIoTClient] handleMIPSStateMessage: no state info in payload for %s: %v\n", did, params)
		return
	}

	// Call OnDeviceStateChanged to update cache and notify subscribers
	c.OnDeviceStateChanged(did, state)
}

// ============================================================================
// MQTT message handling (aligned with Python miot_client.py)
// ============================================================================

// OnPropMsg handles MIPS property messages.
// Aligns with Python: __on_prop_msg.
func (c *MIoTClient) OnPropMsg(params map[string]interface{}, ctx interface{}) {
	// 1. Parse params
	var did string
	var siid, piid int
	var value interface{}

	// Check if wrapped in params.params (cloud MIPS format)
	if inner, ok := params["params"].(map[string]interface{}); ok {
		if d, ok := inner["did"].(string); ok {
			did = d
		}
		if s, ok := inner["siid"].(float64); ok {
			siid = int(s)
		}
		if p, ok := inner["piid"].(float64); ok {
			piid = int(p)
		}
		value = inner["value"]
	} else {
		if d, ok := params["did"].(string); ok {
			did = d
		}
		if s, ok := params["siid"].(float64); ok {
			siid = int(s)
		}
		if p, ok := params["piid"].(float64); ok {
			piid = int(p)
		}
		value = params["value"]
	}

	if did == "" {
		c.lgr.Debugf("[MIoTClient] OnPropMsg: missing did in params=%v\n", params)
		return
	}

	// 2. Match subscription and dispatch to handlers
	topic := fmt.Sprintf("%s/p/%d/%d", did, siid, piid)
	entries := c.subTree.Match(topic)

	for _, entry := range entries {
		// Call handler asynchronously
		go entry.Handler(map[string]interface{}{
			"did":   did,
			"siid":  siid,
			"piid":  piid,
			"value": value,
		}, entry.Ctx)
	}
}

// OnEventMsg handles MIPS event messages.
// Aligns with Python: __on_event_msg.
func (c *MIoTClient) OnEventMsg(params map[string]interface{}, ctx interface{}) {
	// 1. Parse params
	var did string
	var siid, eiid int
	var value interface{}

	if inner, ok := params["params"].(map[string]interface{}); ok {
		if d, ok := inner["did"].(string); ok {
			did = d
		}
		if s, ok := inner["siid"].(float64); ok {
			siid = int(s)
		}
		if e, ok := inner["eiid"].(float64); ok {
			eiid = int(e)
		}
		value = inner["value"]
	} else {
		if d, ok := params["did"].(string); ok {
			did = d
		}
		if s, ok := params["siid"].(float64); ok {
			siid = int(s)
		}
		if e, ok := params["eiid"].(float64); ok {
			eiid = int(e)
		}
		value = params["value"]
	}

	if did == "" {
		c.lgr.Debugf("[MIoTClient] OnEventMsg: missing did in params=%v\n", params)
		return
	}

	// 2. Match subscription and dispatch to handlers
	topic := fmt.Sprintf("%s/e/%d/%d", did, siid, eiid)
	entries := c.subTree.Match(topic)

	for _, entry := range entries {
		// Call handler asynchronously
		go entry.Handler(map[string]interface{}{
			"did":   did,
			"siid":  siid,
			"eiid":  eiid,
			"value": value,
		}, entry.Ctx)
	}
}

// checkDeviceState checks and updates device state from multiple sources.
// Aligns with Python: __check_device_state.
// NOTE: Caller must hold c.deviceListMu (read or write lock).
func (c *MIoTClient) checkDeviceState(did string) bool {
	// Check cloud state
	if dev, ok := c.deviceListCloud[did]; ok {
		if online, ok := dev["online"].(bool); ok && online {
			return true
		}
	}

	// Check gateway state
	if dev, ok := c.deviceListGateway[did]; ok {
		if online, ok := dev["online"].(bool); ok && online {
			return true
		}
	}

	// Check LAN state
	if dev, ok := c.deviceListLan[did]; ok {
		if online, ok := dev["online"].(bool); ok && online {
			return true
		}
	}

	return false
}

// buildPropTopic builds a subscription topic, converting 0 to + wildcard.
// siid=0 → match any siid; piid=0 → match any piid.
func buildPropTopic(did string, siid, piid int) string {
	s := "+"
	p := "+"
	if siid != 0 {
		s = fmt.Sprintf("%d", siid)
	}
	if piid != 0 {
		p = fmt.Sprintf("%d", piid)
	}
	return fmt.Sprintf("%s/p/%s/%s", did, s, p)
}

func buildEventTopic(did string, siid, eiid int) string {
	s := "+"
	e := "+"
	if siid != 0 {
		s = fmt.Sprintf("%d", siid)
	}
	if eiid != 0 {
		e = fmt.Sprintf("%d", eiid)
	}
	return fmt.Sprintf("%s/e/%s/%s", did, s, e)
}