package hue2

import (
	"context"
	"errors"
	"fmt"
	"git.aiterp.net/lucifer/new-server/internal/color"
	"git.aiterp.net/lucifer/new-server/models"
	"golang.org/x/sync/errgroup"
	"log"
	"math"
	"strings"
	"sync"
	"time"
)

type Bridge struct {
	mu          sync.Mutex
	externalID  int
	client      *Client
	needsUpdate chan struct{}
	devices     map[string]models.Device
	resources   map[string]*ResourceData
}

func NewBridge(client *Client) *Bridge {
	return &Bridge{
		client:      client,
		needsUpdate: make(chan struct{}, 4),
		devices:     make(map[string]models.Device, 64),
		resources:   make(map[string]*ResourceData, 256),
	}
}

func (b *Bridge) Run(ctx context.Context, eventCh chan<- models.Event) error {
	log.Println(fmt.Sprintf("[Bridge %d]", b.externalID), "Connecting SSE...")
	sse := b.client.SSE(ctx)

	log.Println(fmt.Sprintf("[Bridge %d]", b.externalID), "Refreshing...")
	err := b.RefreshAll(ctx)
	if err != nil {
		return err
	}
	log.Println(fmt.Sprintf("[Bridge %d]", b.externalID), "Running updates...")
	updated, err := b.MakeCongruent(ctx)
	if err != nil {
		return err
	}
	log.Println(fmt.Sprintf("[Bridge %d]", b.externalID), "Updated", updated, "hue services (startup)")

	lightRefreshTimer := time.NewTicker(time.Second * 5)
	defer lightRefreshTimer.Stop()

	motionTicker := time.NewTicker(time.Second * 10)
	defer motionTicker.Stop()

	absences := make(map[int]time.Time)
	lastPress := make(map[string]time.Time)
	lastUpdate := time.Now()
	needFull := false

	for {
		select {
		case <-ctx.Done():
			return ctx.Err()
		case <-lightRefreshTimer.C:
			if time.Since(lastUpdate) < time.Second*2 {
				continue
			}

			if needFull {
				err := b.RefreshAll(ctx)
				if err != nil {
					return err
				}
			} else {
				err := b.Refresh(ctx, "light")
				if err != nil {
					return err
				}
			}

			updated, err := b.MakeCongruent(ctx)
			if err != nil {
				return err
			}
			if updated > 0 {
				// Force this to cool for 30 seconds unless a manual update occurs.
				if updated > 10 {
					lastUpdate = time.Now().Add(time.Second * 15)
				}

				log.Println(fmt.Sprintf("[Bridge %d]", b.externalID), "Updated", updated, "hue services (regular check)")
			}
		case <-b.needsUpdate:
			lastUpdate = time.Now()

			updated, err := b.MakeCongruent(ctx)
			if err != nil {
				return err
			}
			if updated > 0 {
				log.Println(fmt.Sprintf("[Bridge %d]", b.externalID), "Updated", updated, "hue services (publish)")
			}
		case <-motionTicker.C:
			for id, absenceTime := range absences {
				seconds := int(time.Since(absenceTime).Seconds())
				if seconds < 10 || seconds%60 >= 10 {
					continue
				}

				eventCh <- models.Event{
					Name: models.ENSensorPresenceEnded,
					Payload: map[string]string{
						"deviceId":       fmt.Sprint(id),
						"minutesElapsed": fmt.Sprint(seconds / 60),
						"secondsElapsed": fmt.Sprint(seconds),
						"lastUpdated":    fmt.Sprint(absenceTime.Unix()),
					},
				}
			}
		case data, ok := <-sse:
			if !ok {
				return errors.New("SSE Disconnected")
			}
			b.applyPatches(data.Data)

			updated, err := b.MakeCongruent(ctx)
			if err != nil {
				return err
			}
			if updated > 0 {
				log.Println(fmt.Sprintf("[Bridge %d]", b.externalID), "Updated", updated, "hue services (SSE)")
			}

			for _, patch := range data.Data {
				if patch.Owner == nil {
					continue
				}

				b.mu.Lock()
				if b.resources[patch.Owner.ID] == nil {
					needFull = true
				}
				b.mu.Unlock()

				device, deviceOK := b.devices[patch.Owner.ID]
				if !deviceOK || device.ID == 0 {
					continue
				}

				if patch.Button != nil {
					valid := false
					if patch.Button.LastEvent == "initial_press" || patch.Button.LastEvent == "repeat" {
						valid = true
					} else if patch.Button.LastEvent == "long_release" {
						valid = false
					} else {
						valid = data.CreationTime.Sub(lastPress[patch.ID]) >= time.Second*2
					}

					if valid {
						lastPress[patch.ID] = data.CreationTime

						b.mu.Lock()
						owner := b.resources[patch.Owner.ID]
						b.mu.Unlock()
						if owner != nil {
							index := owner.ServiceIndex("button", patch.ID)
							if index != -1 {
								eventCh <- models.Event{
									Name: models.ENButtonPressed,
									Payload: map[string]string{
										"deviceId":       fmt.Sprint(device.ID),
										"hueButtonEvent": patch.Button.LastEvent,
										"buttonIndex":    fmt.Sprint(index),
										"buttonName":     device.ButtonNames[index],
									},
								}
							}
						}
					}
				}
				if patch.Temperature != nil && patch.Temperature.Valid {
					eventCh <- models.Event{
						Name: models.ENSensorTemperature,
						Payload: map[string]string{
							"deviceId":         fmt.Sprint(device.ID),
							"deviceInternalId": patch.Owner.ID,
							"temperature":      fmt.Sprint(patch.Temperature.Temperature),
							"lastUpdated":      fmt.Sprint(data.CreationTime.Unix()),
						},
					}
				}
				if patch.Motion != nil && patch.Motion.Valid {
					if patch.Motion.Motion {
						eventCh <- models.Event{
							Name: models.ENSensorPresenceStarted,
							Payload: map[string]string{
								"deviceId":         fmt.Sprint(device.ID),
								"deviceInternalId": patch.Owner.ID,
							},
						}

						delete(absences, device.ID)
					} else {
						eventCh <- models.Event{
							Name: models.ENSensorPresenceEnded,
							Payload: map[string]string{
								"deviceId":         fmt.Sprint(device.ID),
								"deviceInternalId": device.InternalID,
								"minutesElapsed":   "0",
								"secondsElapsed":   "0",
								"lastUpdated":      fmt.Sprint(data.CreationTime.Unix()),
							},
						}

						absences[device.ID] = data.CreationTime
					}
				}
			}
		}
	}
}

func (b *Bridge) Update(devices ...models.Device) {
	b.mu.Lock()
	for _, device := range devices {
		b.devices[device.InternalID] = device
	}
	b.mu.Unlock()

	select {
	case b.needsUpdate <- struct{}{}:
	default:
	}
}

func (b *Bridge) MakeCongruent(ctx context.Context) (int, error) {
	// Exhaust the channel to avoid more updates.
	exhausted := false
	for !exhausted {
		select {
		case <-b.needsUpdate:
		default:
			exhausted = true
		}
	}

	b.mu.Lock()
	dur := time.Millisecond * 100
	updates := make(map[string]ResourceUpdate)
	for _, device := range b.devices {
		resource := b.resources[device.InternalID]
		if resource == nil {
			continue
		}

		// Update device
		if resource.Metadata.Name != device.Name {
			name := device.Name
			updates["device/"+resource.ID] = ResourceUpdate{
				Name: &name,
			}
		}

		// Update light
		if lightID := resource.ServiceID("light"); lightID != nil {
			light := b.resources[*lightID]
			update := ResourceUpdate{TransitionDuration: &dur}
			changed := false

			lightsOut := light.Power != nil && !device.State.Power
			if !lightsOut {
				if light.ColorTemperature != nil && device.State.Color.IsKelvin() {
					mirek := 1000000 / *device.State.Color.K
					if mirek < light.ColorTemperature.MirekSchema.MirekMinimum {
						mirek = light.ColorTemperature.MirekSchema.MirekMinimum
					}
					if mirek > light.ColorTemperature.MirekSchema.MirekMaximum {
						mirek = light.ColorTemperature.MirekSchema.MirekMaximum
					}
					if light.ColorTemperature.Mirek == nil || mirek != *light.ColorTemperature.Mirek {
						update.Mirek = &mirek
						changed = true
					}
				} else if xyColor, ok := device.State.Color.ToXY(); ok && light.Color != nil {
					xy := light.Color.Gamut.Conform(*xyColor.XY).Round()
					if xy.DistanceTo(light.Color.XY) > 0.0009 || (light.ColorTemperature != nil && light.ColorTemperature.Mirek != nil) {
						update.ColorXY = &xy
						changed = true
					}
				}
				if light.Dimming != nil && math.Abs(light.Dimming.Brightness/100-device.State.Intensity) > 0.02 {
					brightness := math.Abs(math.Min(device.State.Intensity*100, 100))
					update.Brightness = &brightness
					changed = true
				}
			}

			if light.Power != nil && light.Power.On != device.State.Power {
				update.Power = &device.State.Power
				if device.State.Power {
					brightness := math.Abs(math.Min(device.State.Intensity*100, 100))
					update.Brightness = &brightness
				}
				changed = true
			}

			if changed {
				updates["light/"+light.ID] = update
			}
		}
	}

	if len(updates) > 0 {
		// Optimistically apply the updates to the states, so that the driver assumes they are set until
		// proven otherwise by the SSE client.
		newResources := make(map[string]*ResourceData, len(b.resources))
		for key, value := range b.resources {
			newResources[key] = value
		}
		for key, update := range updates {
			id := strings.SplitN(key, "/", 2)[1]
			newResources[id] = newResources[id].WithUpdate(update)
		}
		b.resources = newResources
	}
	b.mu.Unlock()

	if len(updates) == 0 {
		return 0, nil
	}

	eg, ctx := errgroup.WithContext(ctx)
	for key := range updates {
		update := updates[key]
		split := strings.SplitN(key, "/", 2)
		link := ResourceLink{Kind: split[0], ID: split[1]}

		eg.Go(func() error {
			return b.client.UpdateResource(ctx, link, update)
		})
	}

	err := eg.Wait()
	if err != nil {
		// Try to restore light states.
		_ = b.Refresh(ctx, "light")

		return len(updates), err
	}

	return len(updates), nil
}

func (b *Bridge) GenerateDevices() []models.Device {
	b.mu.Lock()
	resources := b.resources
	b.mu.Unlock()

	devices := make([]models.Device, 0, 16)
	for _, resource := range resources {
		if resource.Type != "device" || strings.HasPrefix(resource.Metadata.Archetype, "bridge") {
			continue
		}

		device := models.Device{
			BridgeID:   b.externalID,
			InternalID: resource.ID,
			Name:       resource.Metadata.Name,
			DriverProperties: map[string]interface{}{
				"archetype": resource.Metadata.Archetype,
				"name":      resource.ProductData.ProductName,
				"product":   resource.ProductData,
				"legacyId":  resource.LegacyID,
			},
		}

		// Set icon
		if resource.ProductData.ProductName == "Hue dimmer switch" {
			device.Icon = "switch"
		} else if resource.ProductData.ProductName == "Hue motion sensor" {
			device.Icon = "sensor"
		} else {
			device.Icon = "lightbulb"
		}

		buttonCount := 0
		for _, ptr := range resource.Services {
			switch ptr.Kind {
			case "device_power":
				{
					device.DriverProperties["battery"] = resources[ptr.ID].PowerState
				}
			case "button":
				{
					buttonCount += 1
				}
			case "zigbee_connectivity":
				{
					device.DriverProperties["zigbee"] = resources[ptr.ID].Status
				}
			case "motion":
				{
					device.Capabilities = append(device.Capabilities, models.DCPresence)
				}
			case "temperature":
				{
					device.Capabilities = append(device.Capabilities, models.DCTemperatureSensor)
				}
			case "light":
				{
					light := resources[ptr.ID]

					if light.Power != nil {
						device.State.Power = light.Power.On
						device.Capabilities = append(device.Capabilities, models.DCPower)
					}
					if light.Dimming != nil {
						device.State.Intensity = light.Dimming.Brightness / 100
						device.Capabilities = append(device.Capabilities, models.DCIntensity)
					}
					if light.ColorTemperature != nil {
						if light.ColorTemperature.Mirek != nil {
							device.State.Color.SetK(1000000 / *light.ColorTemperature.Mirek)
						}
						device.Capabilities = append(device.Capabilities, models.DCColorKelvin)
						device.DriverProperties["maxTemperature"] = 1000000 / light.ColorTemperature.MirekSchema.MirekMinimum
						device.DriverProperties["minTemperature"] = 1000000 / light.ColorTemperature.MirekSchema.MirekMaximum
					}
					if light.Color != nil {
						if device.State.Color.IsEmpty() {
							device.State.Color = color.Color{
								XY: &light.Color.XY,
							}
						}
						device.DriverProperties["colorGamut"] = light.Color.Gamut
						device.DriverProperties["colorGamutType"] = light.Color.GamutType
						device.Capabilities = append(device.Capabilities, models.DCColorHS, models.DCColorXY)
					}
				}
			}
		}
		if buttonCount == 4 {
			device.ButtonNames = []string{"On", "DimUp", "DimDown", "Off"}
		} else if buttonCount == 1 {
			device.ButtonNames = []string{"Button"}
		} else {
			for n := 1; n <= buttonCount; n++ {
				device.ButtonNames = append(device.ButtonNames, fmt.Sprint("Button", n))
			}
		}

		devices = append(devices, device)
	}

	return devices
}

func (b *Bridge) Refresh(ctx context.Context, kind string) error {
	if kind == "device" {
		// Device refresh requires the full deal as services are taken for granted.
		return b.RefreshAll(ctx)
	}

	resources, err := b.client.Resources(ctx, kind)
	if err != nil {
		return err
	}

	b.mu.Lock()
	oldResources := b.resources
	b.mu.Unlock()

	newResources := make(map[string]*ResourceData, len(b.resources))
	for key, value := range oldResources {
		if value.Type != kind {
			newResources[key] = value
		}
	}
	for i := range resources {
		resource := resources[i]
		newResources[resource.ID] = &resource
	}

	b.mu.Lock()
	b.resources = newResources
	b.mu.Unlock()

	return nil
}

func (b *Bridge) RefreshAll(ctx context.Context) error {
	allResources, err := b.client.AllResources(ctx)
	if err != nil {
		return err
	}

	resources := make(map[string]*ResourceData, len(allResources))
	for i := range allResources {
		resource := allResources[i]
		resources[resource.ID] = &resource
	}

	b.mu.Lock()
	b.resources = resources
	b.mu.Unlock()

	return nil
}

func (b *Bridge) applyPatches(patches []ResourceData) {
	b.mu.Lock()
	newResources := make(map[string]*ResourceData, len(b.resources))
	for key, value := range b.resources {
		newResources[key] = value
	}
	b.mu.Unlock()

	for _, patch := range patches {
		if res := newResources[patch.ID]; res != nil {
			resCopy := *res

			if patch.Power != nil && resCopy.Power != nil {
				cp := *resCopy.Power
				resCopy.Power = &cp
				resCopy.Power.On = patch.Power.On
			}
			if patch.Color != nil && resCopy.Color != nil {
				cp := *resCopy.Color
				resCopy.Color = &cp
				resCopy.Color.XY = patch.Color.XY

				if resCopy.ColorTemperature != nil {
					cp2 := *resCopy.ColorTemperature
					resCopy.ColorTemperature = &cp2
					resCopy.ColorTemperature.Mirek = nil
				}
			}
			if patch.ColorTemperature != nil && resCopy.ColorTemperature != nil {
				cp := *resCopy.ColorTemperature
				resCopy.ColorTemperature = &cp
				resCopy.ColorTemperature.Mirek = patch.ColorTemperature.Mirek
			}
			if patch.Dimming != nil && resCopy.Dimming != nil {
				cp := *resCopy.Dimming
				resCopy.Dimming = &cp
				resCopy.Dimming.Brightness = patch.Dimming.Brightness
			}
			if patch.Dynamics != nil {
				resCopy.Dynamics = patch.Dynamics
			}
			if patch.Alert != nil {
				resCopy.Alert = patch.Alert
			}
			if patch.PowerState != nil {
				resCopy.PowerState = patch.PowerState
			}
			if patch.Temperature != nil {
				resCopy.Temperature = patch.Temperature
			}
			if patch.Status != nil {
				resCopy.Status = patch.Status
			}
			resCopy.Metadata.Name = patch.Metadata.Name

			newResources[patch.ID] = &resCopy
		}
	}

	b.mu.Lock()
	b.resources = newResources
	b.mu.Unlock()
}

func (b *Bridge) SearchDevices(ctx context.Context, timeout time.Duration) ([]models.Device, error) {
	// Record the current state.
	b.mu.Lock()
	before := b.resources
	b.mu.Unlock()

	// Spend half the time waiting for devices
	// TODO: Wait for v2 endpoint
	err := b.client.LegacyDiscover(ctx, "sensors")
	if err != nil {
		return nil, err
	}
	select {
	case <-time.After(timeout / 1):
	case <-ctx.Done():
		return nil, ctx.Err()
	}

	// Spend half the time waiting for lights
	// TODO: Wait for v2 endpoint
	err = b.client.LegacyDiscover(ctx, "lights")
	if err != nil {
		return nil, err
	}
	select {
	case <-time.After(timeout / 1):
	case <-ctx.Done():
		return nil, ctx.Err()
	}

	// Perform a full refresh.
	err = b.RefreshAll(ctx)
	if err != nil {
		return nil, err
	}

	// Check for new devices
	devices := b.GenerateDevices()
	newDevices := make([]models.Device, 0)
	for _, device := range devices {
		if before[device.InternalID] == nil {
			newDevices = append(newDevices, device)
		}
	}

	// Return said devices.
	return newDevices, nil
}

func (b *Bridge) Forget(ctx context.Context, device models.Device) error {
	b.mu.Lock()
	resource := b.resources[device.InternalID]
	b.mu.Unlock()

	if resource == nil {
		return errors.New("resource not found")
	}

	return b.client.DeleteResource(ctx, ResourceLink{
		ID:   device.InternalID,
		Kind: "device",
	})
}