package hue

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"git.aiterp.net/lucifer/new-server/models"
	"golang.org/x/sync/errgroup"
	"io"
	"net"
	"net/http"
	"strings"
	"sync"
	"time"
)

type Bridge struct {
	mu             sync.Mutex
	host           string
	token          string
	externalID     int
	lightStates    []*hueLightState
	sensorStates   []*hueSensorState
	syncingPublish uint32
}

func (b *Bridge) Refresh(ctx context.Context) error {
	lightMap, err := b.getLights(ctx)
	if err != nil {
		return err
	}

	b.mu.Lock()
	for index, light := range lightMap {
		var state *hueLightState
		for _, existingState := range b.lightStates {
			if existingState.index == index {
				state = existingState
			}
		}

		if state == nil {
			state = &hueLightState{
				index:      index,
				uniqueID:   light.Uniqueid,
				externalID: -1,
				info:       light,
			}

			b.lightStates = append(b.lightStates, state)
		} else {
			if light.Uniqueid != state.uniqueID {
				state.uniqueID = light.Uniqueid
				state.externalID = -1
			}
		}

		state.CheckStaleness(light.State)
	}
	b.mu.Unlock()

	sensorMap, err := b.getSensors(ctx)
	if err != nil {
		return err
	}

	b.mu.Lock()
	for index, sensor := range sensorMap {
		var state *hueSensorState
		for _, existingState := range b.sensorStates {
			if existingState.index == index {
				state = existingState
			}
		}

		if state == nil {
			state = &hueSensorState{
				index:            index,
				uniqueID:         sensor.UniqueID,
				externalID:       -1,
				presenceCooldown: -2,
			}

			b.sensorStates = append(b.sensorStates, state)
		} else {
			if sensor.UniqueID != state.uniqueID {
				state.uniqueID = sensor.UniqueID
				state.externalID = -1
			}
		}
	}
	b.mu.Unlock()

	return nil
}

func (b *Bridge) SyncStale(ctx context.Context) error {
	indices := make([]int, 0, 4)
	inputs := make([]LightStateInput, 0, 4)

	eg, ctx := errgroup.WithContext(ctx)

	b.mu.Lock()
	for _, state := range b.lightStates {
		if !state.stale {
			continue
		}

		indices = append(indices, state.index)
		inputs = append(inputs, state.input)
	}
	b.mu.Unlock()

	if len(inputs) == 0 {
		return nil
	}

	for i, input := range inputs {
		iCopy := i
		index := indices[i]
		inputCopy := input

		eg.Go(func() error {
			err := b.putLightState(ctx, index, inputCopy)
			if err != nil {
				return err
			}

			b.lightStates[iCopy].stale = false

			return nil
		})
	}

	return eg.Wait()
}

func (b *Bridge) SyncSensors(ctx context.Context) ([]models.Event, error) {
	sensorMap, err := b.getSensors(ctx)
	if err != nil {
		return nil, err
	}

	var events []models.Event

	b.mu.Lock()
	for idx, sensorData := range sensorMap {
		for _, state := range b.sensorStates {
			if idx == state.index {
				event := state.Update(sensorData)
				if event != nil {
					events = append(events, *event)
				}

				break
			}
		}
	}
	b.mu.Unlock()

	return events, nil
}

func (b *Bridge) StartDiscovery(ctx context.Context, model string) error {
	return b.post(ctx, model, nil, nil)
}

func (b *Bridge) putLightState(ctx context.Context, index int, input LightStateInput) error {
	return b.put(ctx, fmt.Sprintf("lights/%d/state", index), input, nil)
}

func (b *Bridge) getToken(ctx context.Context) (string, error) {
	result := make([]CreateUserResponse, 0, 1)
	err := b.post(ctx, "", CreateUserInput{DeviceType: "git.aiterp.net/lucifer"}, &result)
	if err != nil {
		return "", err
	}

	if len(result) == 0 || result[0].Error != nil {
		return "", errLinkButtonNotPressed
	}
	if result[0].Success == nil {
		return "", models.ErrUnexpectedResponse
	}

	return result[0].Success.Username, nil
}

func (b *Bridge) getLights(ctx context.Context) (map[int]LightData, error) {
	result := make(map[int]LightData, 16)
	err := b.get(ctx, "lights", &result)
	if err != nil {
		return nil, err
	}

	return result, nil
}

func (b *Bridge) getSensors(ctx context.Context) (map[int]SensorData, error) {
	result := make(map[int]SensorData, 16)
	err := b.get(ctx, "sensors", &result)
	if err != nil {
		return nil, err
	}

	return result, nil
}

func (b *Bridge) get(ctx context.Context, resource string, target interface{}) error {
	if b.token != "" {
		resource = b.token + "/" + resource
	}

	req, err := http.NewRequest("GET", fmt.Sprintf("http://%s/api/%s", b.host, resource), nil)
	if err != nil {
		return err
	}

	res, err := httpClient.Do(req.WithContext(ctx))
	if err != nil {
		return err
	}
	defer res.Body.Close()

	return json.NewDecoder(res.Body).Decode(target)
}

func (b *Bridge) post(ctx context.Context, resource string, body interface{}, target interface{}) error {
	rb, err := reqBody(body)
	if err != nil {
		return err
	}

	if b.token != "" {
		resource = b.token + "/" + resource
	}

	req, err := http.NewRequest("POST", fmt.Sprintf("http://%s/api/%s", b.host, resource), rb)
	if err != nil {
		return err
	}

	res, err := httpClient.Do(req.WithContext(ctx))
	if err != nil {
		return err
	}
	defer res.Body.Close()

	if target == nil {
		return nil
	}

	return json.NewDecoder(res.Body).Decode(target)
}

func (b *Bridge) put(ctx context.Context, resource string, body interface{}, target interface{}) error {
	rb, err := reqBody(body)
	if err != nil {
		return err
	}

	if b.token != "" {
		resource = b.token + "/" + resource
	}

	req, err := http.NewRequest("PUT", fmt.Sprintf("http://%s/api/%s", b.host, resource), rb)
	if err != nil {
		return err
	}

	res, err := httpClient.Do(req.WithContext(ctx))
	if err != nil {
		return err
	}
	defer res.Body.Close()

	if target == nil {
		return nil
	}

	return json.NewDecoder(res.Body).Decode(target)
}

func reqBody(body interface{}) (io.Reader, error) {
	if body == nil {
		return nil, nil
	}

	switch v := body.(type) {
	case []byte:
		return bytes.NewReader(v), nil
	case string:
		return strings.NewReader(v), nil
	case io.Reader:
		return v, nil
	default:
		jsonData, err := json.Marshal(v)
		if err != nil {
			return nil, err
		}

		return bytes.NewReader(jsonData), nil
	}
}

var httpClient = &http.Client{
	Transport: &http.Transport{
		Proxy: http.ProxyFromEnvironment,
		DialContext: (&net.Dialer{
			Timeout:   30 * time.Second,
			KeepAlive: 30 * time.Second,
		}).DialContext,
		MaxIdleConns:        256,
		MaxIdleConnsPerHost: 16,
		IdleConnTimeout:     10 * time.Minute,
	},
	Timeout: time.Minute,
}