package scene

import (
	"context"
	"git.aiterp.net/lucifer/new-server/app/config"
	"git.aiterp.net/lucifer/new-server/models"
	"log"
	"sync"
	"time"
)

type Manager struct {
	mu          sync.Mutex
	allocations map[int]*Scene
	devices     map[int]*models.Device
	scenes      []*Scene

	notifyCh chan struct{}
}

func (mgr *Manager) UpdateDevice(ctx context.Context, device *models.Device, data *models.Scene) error {
	mgr.mu.Lock()
	defer mgr.mu.Unlock()

	scene, err := mgr.findScene(ctx, device.SceneAssignments, data)
	if err != nil {
		return err
	}

	if mgr.allocations[device.ID] != nil && mgr.allocations[device.ID] != scene {
		mgr.allocations[device.ID].RemoveDevice(*device)
	}

	if mgr.allocations[device.ID] != scene {
		if mgr.allocations == nil {
			mgr.allocations = make(map[int]*Scene, 8)
		}

		mgr.allocations[device.ID] = scene

		if scene != nil {
			scene.due = true
		}
	}

	if scene != nil {
		scene.UpsertDevice(*device)

		if mgr.devices == nil {
			mgr.devices = make(map[int]*models.Device)
		}
		mgr.devices[device.ID] = device
	} else {
		config.PublishChannel <- []models.Device{*device}
	}

	if mgr.notifyCh != nil {
		close(mgr.notifyCh)
		mgr.notifyCh = nil
	}

	return nil
}

func (mgr *Manager) UpdateScene(data *models.Scene) {
	mgr.mu.Lock()
	for _, scene := range mgr.scenes {
		if scene.data.ID == data.ID {
			scene.UpdateScene(scene.data)
		}
	}
	mgr.mu.Unlock()
}

func (mgr *Manager) FilterUnassigned(devices []models.Device) []models.Device {
	mgr.mu.Lock()
	defer mgr.mu.Unlock()

	res := make([]models.Device, 0, len(devices))
	for _, device := range devices {
		if mgr.allocations[device.ID] == nil {
			res = append(res, device)
		}
	}

	return res
}

func (mgr *Manager) Run(ctx context.Context) {
	devices, err := config.DeviceRepository().FetchByReference(ctx, models.RKAll, "")
	if err == nil {
		for _, device := range devices {
			_ = mgr.UpdateDevice(ctx, &device, nil)
		}
	}

	ticker := time.NewTicker(time.Millisecond * 101)
	defer ticker.Stop()

	mgr.mu.Lock()
	mgr.notifyCh = make(chan struct{})
	mgr.mu.Unlock()

	for {
		mgr.mu.Lock()
		if mgr.notifyCh == nil {
			mgr.notifyCh = make(chan struct{})
		}
		notifyCh := mgr.notifyCh
		mgr.mu.Unlock()

		select {
		case <-ticker.C:
		case <-notifyCh:
		case <-ctx.Done():
			return
		}

		timeout, cancel := context.WithTimeout(ctx, time.Millisecond*100)

		var updates []models.Device
		mgr.mu.Lock()
		for _, device := range mgr.devices {
			if device == nil {
				continue
			}

			if mgr.reScene(timeout, device) {
				updates = append(updates, *device)
			}
		}

		for _, scene := range mgr.scenes {
			if scene.Due() {
				scene.Run()
			}

			updates = append(updates, scene.Flush()...)
		}
		mgr.mu.Unlock()

		cancel()

		if len(updates) > 0 {
			log.Println("Updating", len(updates), "devices")
			config.PublishChannel <- updates
		}
	}
}

func (mgr *Manager) reScene(ctx context.Context, device *models.Device) bool {
	scene, err := mgr.findScene(ctx, device.SceneAssignments, nil)
	if err != nil {
		return false
	}

	if mgr.allocations[device.ID] != nil && mgr.allocations[device.ID] != scene {
		mgr.allocations[device.ID].RemoveDevice(*device)
	}
	if mgr.allocations[device.ID] != scene {
		if mgr.allocations == nil {
			mgr.allocations = make(map[int]*Scene, 8)
		}

		mgr.allocations[device.ID] = scene

		if scene == nil {
			return true
		}

		mgr.allocations[device.ID].UpsertDevice(*device)
	}

	return false
}

func (mgr *Manager) findScene(ctx context.Context, assignments []models.DeviceSceneAssignment, data *models.Scene) (*Scene, error) {
	if len(assignments) == 0 {
		return nil, nil
	}

	var selected *models.DeviceSceneAssignment
	for _, assignment := range assignments {
		pos := int64(time.Since(assignment.StartTime) / time.Millisecond)
		if assignment.DurationMS == 0 || (pos >= -1 && pos < assignment.DurationMS) {
			selected = &assignment
		}
	}
	if selected == nil {
		return nil, nil
	}

	for _, scene := range mgr.scenes {
		if scene.group == selected.Group && scene.startTime.Equal(selected.StartTime) && selected.DurationMS == scene.duration.Milliseconds() {
			return scene, nil
		}
	}

	if data == nil {
		for i := range mgr.scenes {
			if mgr.scenes[i].data.ID == selected.SceneID {
				data = &mgr.scenes[i].data
				break
			}
		}
	}

	if data == nil {
		var err error
		data, err = config.SceneRepository().Find(ctx, selected.SceneID)
		if err != nil {
			return nil, err
		}
	}

	scene := &Scene{
		startTime: selected.StartTime,
		duration:  time.Duration(selected.DurationMS) * time.Millisecond,
		lastRun:   0,
		due:       true,
		group:     selected.Group,
		data:      *data,
		roleList:  make([][]models.Device, len(data.Roles)),
		deviceMap: make(map[int]*models.Device, 8),
		roleMap:   make(map[int]int, 8),
		changes:   make(map[int]models.NewDeviceState, 8),
	}

	mgr.scenes = append(mgr.scenes, scene)

	return scene, nil
}

var globalManager = &Manager{}

func GlobalManager() *Manager {
	return globalManager
}