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

import (
	"fmt"
	"reflect"
	"regexp"
	"strings"
	"time"
)

// subDevPattern matches .s\d+ suffix for sub-devices.
var subDevPattern = regexp.MustCompile(`\.s\d+$`)

// ============================================================================
// Device instance management
// ============================================================================

// getOrCreateDevice returns or creates a MIoTDevice instance for the given DID.
// Lazily parses SPEC on first access and caches the result.
func (c *MIoTClient) getOrCreateDevice(did string, info map[string]interface{}) *MIoTDevice {
	c.mu.RLock()
	if dev, ok := c.devices[did]; ok {
		c.mu.RUnlock()
		return dev
	}
	c.mu.RUnlock()

	if c.specParser == nil {
		return nil
	}

	urn, _ := info["urn"].(string)
	model, _ := info["model"].(string)
	if urn == "" && model == "" {
		urn, _ = info["type"].(string)
	}

	spec, err := c.specParser.Parse(urn, model)
	if err != nil {
		c.lgr.Errorf("[MIoTClient] getOrCreateDevice: SPEC parse failed for %s (%s/%s): %v\n", did, urn, model, err)
		return nil
	}

	c.mu.Lock()
	defer c.mu.Unlock()
	// Double-check after acquiring write lock
	if dev, ok := c.devices[did]; ok {
		return dev
	}
	dev := NewMIoTDevice(c, info, spec)
	if c.devices == nil {
		c.devices = make(map[string]*MIoTDevice)
	}
	c.devices[did] = dev
	return dev
}

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

// RefreshDevices refreshes device list from cloud for the given home IDs (nil=all).
// Aligns with Python: __update_devices_from_cloud_async (line 1384).
func (c *MIoTClient) RefreshDevices(homeIDs []string) error {
	if c.http == nil {
		return fmt.Errorf("HTTP client not available")
	}

	// 1. Get full device list from cloud
	result, err := c.http.GetDevices(homeIDs)
	if err != nil {
		return fmt.Errorf("failed to get devices: %v", err)
	}

	devicesRaw, ok := result["devices"].(map[string]map[string]interface{})
	if !ok {
		// Try interface{} cast
		dev, ok := result["devices"].(map[string]interface{})
		if !ok {
			return fmt.Errorf("invalid devices response")
		}
		devicesRaw = make(map[string]map[string]interface{})
		for did, info := range dev {
			if infoMap, ok := info.(map[string]interface{}); ok {
				devicesRaw[did] = infoMap
			}
		}
	}

	c.deviceListMu.Lock()
	defer c.deviceListMu.Unlock()

	// 2. Build processed device maps
	cloudDevices := make(map[string]map[string]interface{})
	sharedDevices := make(map[string]map[string]interface{})
	subDevices := make(map[string]map[string]map[string]interface{}) // parentDID -> subKey -> device

	for did, device := range devicesRaw {
		// Clone device info
		info := make(map[string]interface{})
		for k, v := range device {
			info[k] = v
		}

		// Handle sub-devices: .s\d+ suffix
		match := subDevPattern.FindString(did)
		if match != "" {
			parentDID := strings.TrimSuffix(did, match)
			subKey := strings.TrimPrefix(match, ".")
			if subDevices[parentDID] == nil {
				subDevices[parentDID] = make(map[string]map[string]interface{})
			}
			subDevices[parentDID][subKey] = info
			continue
		}

		// Handle shared devices: owner.userid exists
		if isSharedDevice(info) {
			sharedDevices[did] = info
			continue
		}

		cloudDevices[did] = info
	}

	// Merge sub-devices into parents
	for parentDID, subs := range subDevices {
		if parent, exists := cloudDevices[parentDID]; exists {
			if parent["sub_devices"] == nil {
				parent["sub_devices"] = make(map[string]interface{})
			}
			existingSubs, _ := parent["sub_devices"].(map[string]interface{})
			for subKey, subInfo := range subs {
				existingSubs[subKey] = subInfo
			}
		}
	}

	// 3. Merge shared devices into cloud devices (python treats them the same)
	for did, info := range sharedDevices {
		cloudDevices[did] = info
	}

	// 4. Diff: compare cloudDevices with current deviceListCloud
	changed := false

	// Detect additions and updates
	for did, info := range cloudDevices {
		oldInfo, exists := c.deviceListCloud[did]
		if !exists {
			// New device
			c.deviceListCloud[did] = info
			if cacheInfo, cacheExists := c.deviceListCache[did]; cacheExists {
				// Update existing cache entry
				for k, v := range info {
					cacheInfo[k] = v
				}
			} else {
				c.deviceListCache[did] = cloneMap(info)
			}
			c.lgr.Debugf("[MIoTClient] Device added: %s (%v)\n", did, info["name"])
			changed = true
		} else {
			// 检测并同步所有变更字段（name/model/nickname 等）
			for k, v := range info {
				if oldV, ok := oldInfo[k]; !ok || !reflect.DeepEqual(oldV, v) {
					oldInfo[k] = v
					changed = true
				}
			}
			c.deviceListCloud[did] = oldInfo
			if cacheInfo, ok := c.deviceListCache[did]; ok {
				for k, v := range info {
					cacheInfo[k] = v
				}
			}
		}
	}

	// Detect deletions
	for did := range c.deviceListCloud {
		if _, exists := cloudDevices[did]; !exists {
			delete(c.deviceListCloud, did)
			if cacheInfo, ok := c.deviceListCache[did]; ok {
				cacheInfo["online"] = false
				cacheInfo["push_available"] = false
			}
			c.lgr.Infof("[MIoTClient] Device removed from cloud: %s\n", did)
			changed = true
		}
	}

	// 4. Aggregate three sources: cloud + gateway + lan
	for did := range c.deviceListCache {
		c.aggregateDeviceState(did)
	}

	// 5. Update subscription routing
	for did := range cloudDevices {
		c.updateDeviceMsgSub(did)
	}

	// 6. Save device list to storage
	if c.storage != nil {
		deviceListForStorage := make(map[string]interface{})
		for did, info := range c.deviceListCache {
			deviceListForStorage[did] = info
		}
		deviceKey := fmt.Sprintf("%s_%s", c.uid, c.cloudServer)
		if err := c.storage.Save("miot_devices", deviceKey, deviceListForStorage); err != nil {
			c.lgr.Warnf("[MIoTClient] Warning: failed to save devices: %v\n", err)
		}
	}

	// 7. Notify device list changed
	if changed {
		c.ShowDevicesChangedNotify()
	}

	c.lgr.Infof("[MIoTClient] Devices refreshed: cloud=%d, cache=%d\n", len(cloudDevices), len(c.deviceListCache))
	return nil
}

// ============================================================================
// Helper functions for device list management
// ============================================================================

// getConnectType extracts the connect_type from device info.
// Returns 0 if not found.
func getConnectType(info map[string]interface{}) int {
	if ct, ok := info["connect_type"].(float64); ok {
		return int(ct)
	}
	return 0
}

// getOnline extracts the online status from device info.
func getOnline(info map[string]interface{}) bool {
	if online, ok := info["online"].(bool); ok {
		return online
	}
	return false
}

// isSharedDevice checks if a device has an owner with a userid (shared device).
func isSharedDevice(info map[string]interface{}) bool {
	owner, ok := info["owner"].(map[string]interface{})
	if !ok || owner == nil {
		return false
	}
	_, hasUserID := owner["userid"]
	return hasUserID
}

// cloneMap performs a shallow clone of a map.
func cloneMap(src map[string]interface{}) map[string]interface{} {
	dst := make(map[string]interface{}, len(src))
	for k, v := range src {
		dst[k] = v
	}
	return dst
}

// aggregateDeviceState merges cloud/gateway/lan state for a device into cache.
// Aligns with Python: __check_device_state.
func (c *MIoTClient) aggregateDeviceState(did string) {
	// NOTE: caller must hold c.deviceListMu

	cacheInfo, cacheExists := c.deviceListCache[did]
	if !cacheExists {
		return
	}

	// OR 聚合：任一来源显式 online=true → 在线；
	// 否则任一来源显式 online=false → 离线；
	// 否则（无来源提供 online 字段）→ 保留缓存旧值，缓存也没有则默认在线。
	online := false
	explicitTrue := false
	explicitFalse := false

	sources := []map[string]interface{}{
		c.deviceListCloud[did],
		c.deviceListGateway[did],
		c.deviceListLan[did],
	}
	for _, info := range sources {
		if o, ok := info["online"].(bool); ok {
			if o {
				explicitTrue = true
			} else {
				explicitFalse = true
			}
		} else if _, exists := info["online"]; exists {
			c.lgr.Debugf("[MIoTClient] %s online type mismatch: %v (%T)\n", did, info["online"], info["online"])
		}
	}

	switch {
	case explicitTrue:
		online = true
	case explicitFalse:
		online = false
	default:
		if oldOnline, ok := cacheInfo["online"].(bool); ok {
			online = oldOnline
		} else {
			online = true // 云列表里有但没 online 字段，假设在线
		}
		c.lgr.Debugf("[MIoTClient] %s no online field from cloud/gw/lan, fallback online=%v (cache=%v)\n",
			did, online, cacheInfo["online"])
	}

	cacheInfo["online"] = online
}

// LoadDevices loads devices from cache or cloud.
// Aligns with Python: __load_cache_device_async.
func (c *MIoTClient) LoadDevices() error {
	// Try to load from cache first
	if err := c.loadCacheDevice(); err != nil {
		c.lgr.Errorf("[MIoTClient] Failed to load from cache: %v\n", err)
	}

	// Then refresh from cloud
	return c.RefreshDevices(c.homeIDs)
}

// GetDeviceInfo returns device metadata for a given DID.
// Returns nil if device not found.
// Aligns with Python: device_list.get(did).
func (c *MIoTClient) GetDeviceInfo(did string) map[string]interface{} {
	c.deviceListMu.RLock()
	defer c.deviceListMu.RUnlock()

	if info, ok := c.deviceListCache[did]; ok {
		return info
	}

	return nil
}

// GetDeviceInfos returns all device metadata.
// Aligns with Python: device_list property.
func (c *MIoTClient) GetDeviceInfos() map[string]map[string]interface{} {
	c.deviceListMu.RLock()
	defer c.deviceListMu.RUnlock()

	// Return a copy
	result := make(map[string]map[string]interface{})
	for did, info := range c.deviceListCache {
		result[did] = info
	}

	return result
}

// ScheduleRefreshDevices schedules a device refresh after delay.
// Aligns with Python: __request_refresh_cloud_devices.
func (c *MIoTClient) ScheduleRefreshDevices(delay time.Duration) {
	c.mu.Lock()
	defer c.mu.Unlock()

	// Cancel previous timer if exists
	if c.refreshCloudDevicesTimer != nil {
		c.refreshCloudDevicesTimer.Stop()
	}

	c.refreshCloudDevicesTimer = time.AfterFunc(delay, func() {
		c.lgr.Infof("[MIoTClient] Refreshing devices...\n")
		if err := c.RefreshDevices(c.homeIDs); err != nil {
			c.lgr.Errorf("[MIoTClient] Refresh failed, will retry: %v\n", err)
			// Retry after 60s
			c.ScheduleRefreshDevices(RefreshCloudDevicesRetryDelay * time.Millisecond)
		}
	})

	c.lgr.Infof("[MIoTClient] Device refresh scheduled in %v\n", delay)
}

// Start starts the MIoTClient and schedules initial device load.
// Aligns with Python: init_async called at startup.
func (c *MIoTClient) Start() error {
	// Initialize
	if err := c.Init(); err != nil {
		return err
	}

	// Schedule initial device load (delayed, aligns with REFRESH_CLOUD_DEVICES_DELAY=6 in Python)
	c.ScheduleRefreshDevices(RefreshCloudDevicesDelay * time.Millisecond)

	c.lgr.Infof("[MIoTClient] Started\n")
	return nil
}

// Stop stops the MIoTClient and all timers.
func (c *MIoTClient) Stop() error {
	return c.Deinit()
}

// ============================================================================
// Device state change handling (aligned with Python miot_client.py)
// ============================================================================

// OnDeviceStateChanged handles device state changes.
// Aligns with Python: __on_cloud_device_state_changed.
func (c *MIoTClient) OnDeviceStateChanged(did string, state interface{}) {
	c.deviceListMu.Lock()
	defer c.deviceListMu.Unlock()

	stateMap, ok := state.(map[string]interface{})
	if !ok {
		return
	}

	// Update or create entry in deviceListCloud (the source triggering this callback)
	if dev, ok := c.deviceListCloud[did]; ok {
		for k, v := range stateMap {
			dev[k] = v
		}
	} else if _, ok := stateMap["online"]; ok {
		c.deviceListCloud[did] = cloneMap(stateMap)
	}

	// Aggregate from three sources before updating cache
	c.aggregateDeviceState(did)

	// Propagate to subDeviceState subscribers
	if handler, ok := c.subDeviceState[did]; ok {
		go handler.Handler(did, state)
	}
}