// Package iotmock implements a simulated IoT device provider for development and testing.
// It provides 8 virtual smart home devices with realistic behavior including
// sensor fluctuation and operation history tracking.
package iotmock

import (
	"context"
	"fmt"
	"math/rand"
	"sync"
	"time"

	"git.yeij.top/AskaEth/Cyrene_v2/internal/plugin"
)

// Plugin implements the IoTProvider interface with 8 simulated devices.
type Plugin struct {
	devices map[string]*plugin.Device
	subs    []chan plugin.DeviceEvent
	mu      sync.RWMutex
	stopCh  chan struct{}
	stopped bool
}

// New creates a new iot-mock plugin with 8 pre-configured devices.
func New() *Plugin {
	return &Plugin{
		devices: map[string]*plugin.Device{
			"light-livingroom": {
				ID: "light-livingroom", Name: "客厅灯", Type: plugin.DeviceLight,
				State: map[string]any{"power": false, "brightness": 80, "color": "warm_white"},
				Online: true,
			},
			"light-bedroom": {
				ID: "light-bedroom", Name: "卧室灯", Type: plugin.DeviceLight,
				State: map[string]any{"power": false, "brightness": 60, "color": "warm_white"},
				Online: true,
			},
			"ac-livingroom": {
				ID: "ac-livingroom", Name: "客厅空调", Type: plugin.DeviceAC,
				State: map[string]any{"power": false, "temperature": 26, "mode": "cool"},
				Online: true,
			},
			"ac-bedroom": {
				ID: "ac-bedroom", Name: "卧室空调", Type: plugin.DeviceAC,
				State: map[string]any{"power": false, "temperature": 25, "mode": "cool"},
				Online: true,
			},
			"curtain-livingroom": {
				ID: "curtain-livingroom", Name: "客厅窗帘", Type: plugin.DeviceCurtain,
				State: map[string]any{"power": false, "position": 0},
				Online: true,
			},
			"sensor-temperature": {
				ID: "sensor-temperature", Name: "温度传感器", Type: plugin.DeviceSensor,
				State: map[string]any{"temperature": 25.0, "unit": "celsius"},
				Online: true,
			},
			"sensor-humidity": {
				ID: "sensor-humidity", Name: "湿度传感器", Type: plugin.DeviceSensor,
				State: map[string]any{"humidity": 55.0, "unit": "percent"},
				Online: true,
			},
			"lock-door": {
				ID: "lock-door", Name: "智能门锁", Type: plugin.DeviceLock,
				State: map[string]any{"locked": true, "battery": 85},
				Online: true,
			},
		},
		subs:   make([]chan plugin.DeviceEvent, 0),
		stopCh: make(chan struct{}),
	}
}

// --- Plugin interface ---

func (p *Plugin) Name() string        { return "iot-mock" }
func (p *Plugin) Version() string     { return "1.0.0" }
func (p *Plugin) Description() string { return "模拟8个智能家居设备，仅供开发测试使用" }
func (p *Plugin) Enabled() bool       { return true }

func (p *Plugin) Init(_ context.Context, _ plugin.PluginConfig) error {
	// Start sensor fluctuation goroutine
	go p.fluctuateSensors()
	return nil
}

func (p *Plugin) Close() error {
	p.mu.Lock()
	defer p.mu.Unlock()
	if p.stopped {
		return nil
	}
	p.stopped = true
	close(p.stopCh)
	for _, ch := range p.subs {
		close(ch)
	}
	p.subs = nil
	return nil
}

// --- IoTProvider interface ---

func (p *Plugin) ListDevices(_ context.Context) ([]plugin.Device, error) {
	p.mu.RLock()
	defer p.mu.RUnlock()

	result := make([]plugin.Device, 0, len(p.devices))
	for _, d := range p.devices {
		// Return a copy to prevent external mutation
		clone := *d
		clone.State = make(map[string]any, len(d.State))
		for k, v := range d.State {
			clone.State[k] = v
		}
		result = append(result, clone)
	}
	return result, nil
}

func (p *Plugin) GetDevice(_ context.Context, id string) (*plugin.Device, error) {
	p.mu.RLock()
	defer p.mu.RUnlock()

	d, ok := p.devices[id]
	if !ok {
		return nil, fmt.Errorf("device %s not found", id)
	}
	clone := *d
	clone.State = make(map[string]any, len(d.State))
	for k, v := range d.State {
		clone.State[k] = v
	}
	return &clone, nil
}

func (p *Plugin) SetDevice(_ context.Context, id, field string, value any) error {
	p.mu.Lock()
	defer p.mu.Unlock()

	d, ok := p.devices[id]
	if !ok {
		return fmt.Errorf("device %s not found", id)
	}

	oldValue := d.State[field]
	d.State[field] = value

	event := plugin.DeviceEvent{
		DeviceID:  id,
		Field:     field,
		OldValue:  oldValue,
		NewValue:  value,
		Timestamp: time.Now().Unix(),
	}
	d.History = append(d.History, event)
	// Keep only last 20 history events
	if len(d.History) > 20 {
		d.History = d.History[len(d.History)-20:]
	}

	// Broadcast to subscribers
	p.broadcast(event)

	return nil
}

func (p *Plugin) ToggleDevice(_ context.Context, id string) error {
	p.mu.RLock()
	d, ok := p.devices[id]
	p.mu.RUnlock()
	if !ok {
		return fmt.Errorf("device %s not found", id)
	}

	currentPower, _ := d.State["power"].(bool)
	return p.SetDevice(context.Background(), id, "power", !currentPower)
}

func (p *Plugin) SubscribeChanges(_ context.Context) (<-chan plugin.DeviceEvent, error) {
	p.mu.Lock()
	defer p.mu.Unlock()

	ch := make(chan plugin.DeviceEvent, 32)
	p.subs = append(p.subs, ch)
	return ch, nil
}

// --- Internal ---

func (p *Plugin) broadcast(event plugin.DeviceEvent) {
	for _, ch := range p.subs {
		select {
		case ch <- event:
		default:
			// Subscriber is too slow, drop event
		}
	}
}

// fluctuateSensors simulates temperature and humidity changes every 30 seconds.
func (p *Plugin) fluctuateSensors() {
	ticker := time.NewTicker(30 * time.Second)
	defer ticker.Stop()

	for {
		select {
		case <-p.stopCh:
			return
		case <-ticker.C:
			// Fluctuate temperature sensor: ±0.2°C
			p.fluctuateDeviceField("sensor-temperature", "temperature", 0.2)

			// Fluctuate humidity sensor: ±1%
			p.fluctuateDeviceField("sensor-humidity", "humidity", 1.0)
		}
	}
}

func (p *Plugin) fluctuateDeviceField(deviceID, field string, maxDelta float64) {
	p.mu.Lock()
	d, ok := p.devices[deviceID]
	if !ok {
		p.mu.Unlock()
		return
	}

	current, ok := d.State[field].(float64)
	if !ok {
		p.mu.Unlock()
		return
	}

	delta := (rand.Float64()*2 - 1) * maxDelta
	newVal := current + delta
	// Round to 1 decimal place
	newVal = float64(int(newVal*10)) / 10

	oldVal := d.State[field]
	d.State[field] = newVal
	p.mu.Unlock()

	p.mu.RLock()
	event := plugin.DeviceEvent{
		DeviceID:  deviceID,
		Field:     field,
		OldValue:  oldVal,
		NewValue:  newVal,
		Timestamp: time.Now().Unix(),
	}
	p.mu.RUnlock()

	p.broadcast(event)
}