package v1

import (
	"context"
	"strconv"
	"strings"
	"sync"

	"forge.cadoles.com/cadoles/go-emlid/reach/client/protocol"
	"forge.cadoles.com/cadoles/go-emlid/reach/client/protocol/v1/model"
	"forge.cadoles.com/cadoles/go-emlid/reach/client/socketio"
	"github.com/pkg/errors"
)

type Operations struct {
	addr   string
	client *socketio.Client
	mutex  sync.RWMutex
}

// Close implements protocol.Operations.
func (o *Operations) Close(ctx context.Context) error {
	o.mutex.Lock()
	defer o.mutex.Unlock()

	if o.client == nil {
		return nil
	}

	o.client.Close()

	return nil
}

const (
	// EventBrowserConnected is emitted after the initial connection to the
	// ReachView endpoint
	eventBrowserConnected = "browser connected"
)

// Connect implements protocol.Operations.
func (o *Operations) Connect(ctx context.Context) error {
	o.mutex.Lock()
	defer o.mutex.Unlock()

	if o.client != nil {
		o.client.Close()
	}

	endpoint, err := socketio.EndpointFromHAddr(o.addr)
	if err != nil {
		return errors.WithStack(err)
	}

	client := socketio.NewClient(endpoint)

	if err := client.Connect(); err != nil {
		return errors.WithStack(err)
	}

	// Notifies the ReachView endpoint of a new connection.
	// See misc/reachview/update_main.js line 297
	payload := map[string]string{
		"data": "I'm connected",
	}
	if err := client.Emit(eventBrowserConnected, payload); err != nil {
		return errors.WithStack(err)
	}

	o.client = client

	return nil
}

// Emit implements protocol.Operations.
func (o *Operations) Emit(ctx context.Context, mType string, message any) error {
	o.mutex.RLock()
	defer o.mutex.RUnlock()

	if o.client == nil || !o.client.Alive() {
		return errors.WithStack(protocol.ErrClosed)
	}

	if err := o.client.Emit(mType, message); err != nil {
		return errors.WithStack(err)
	}

	return nil
}

// On implements protocol.Operations.
func (o *Operations) On(ctx context.Context, event string) (chan any, error) {
	o.mutex.RLock()
	defer o.mutex.RUnlock()

	if o.client == nil || !o.client.Alive() {
		return nil, errors.WithStack(protocol.ErrClosed)
	}

	out := make(chan any)
	closer := new(sync.Once)

	handler := func(ch *socketio.Channel, data any) {
		select {
		case <-ctx.Done():
			closer.Do(func() {
				o.mutex.RLock()
				defer o.mutex.RUnlock()

				ch.Close()
				close(out)

				if o.client == nil {
					return
				}
			})

			return
		default:
			out <- data
		}
	}

	if err := o.client.On(event, handler); err != nil {
		return nil, errors.WithStack(err)
	}

	return out, nil
}

// Alive implements protocol.Operations.
func (o *Operations) Alive(ctx context.Context) (bool, error) {
	o.mutex.RLock()
	defer o.mutex.RUnlock()

	if o.client == nil || !o.client.Alive() {
		return false, errors.WithStack(protocol.ErrClosed)
	}

	return o.client.Alive(), nil
}

// Configuration implements protocol.Operations.
func (o *Operations) Configuration(ctx context.Context) (any, error) {
	config, err := o.RequestConfiguration(ctx)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	return config, nil
}

const (
	eventReboot = "reboot"
)

// Reboot implements protocol.Operations.
func (o *Operations) Reboot(ctx context.Context) error {
	o.mutex.RLock()
	defer o.mutex.RUnlock()

	if o.client == nil || !o.client.Alive() {
		return errors.WithStack(protocol.ErrClosed)
	}

	var err error
	var wg sync.WaitGroup

	var once sync.Once

	done := func() {
		o.client.Off(socketio.OnDisconnection)
		wg.Done()
	}

	wg.Add(1)

	go func() {
		<-ctx.Done()
		err = ctx.Err()
		once.Do(done)
	}()

	err = o.client.On(socketio.OnDisconnection, func(h *socketio.Channel, data any) {
		once.Do(done)
	})
	if err != nil {
		return errors.Wrapf(err, "error while binding to '%s' event", socketio.OnDisconnection)
	}

	if err = o.client.Emit(eventReboot, nil); err != nil {
		return err
	}

	wg.Wait()

	return err
}

const (
	// ConfigurationApplySuccess -
	configurationApplySuccess = "success"
	// ConfigurationApplyFailed -
	configurationApplyFailed = "failed"
)

// SetBase implements protocol.Operations.
func (o *Operations) SetBase(ctx context.Context, funcs ...protocol.SetBaseOptionFunc) error {
	opts := protocol.NewSetBaseOptions(funcs...)

	var lat string
	if opts.Latitude != nil {
		lat = strconv.FormatFloat(*opts.Latitude, 'f', -1, 64)
	}

	var lon string
	if opts.Longitude != nil {
		lon = strconv.FormatFloat(*opts.Longitude, 'f', -1, 64)
	}

	var alt string
	if opts.Height != nil {
		alt = strconv.FormatFloat(*opts.Height, 'f', -1, 64)
	}

	var antennaHeight string
	if opts.AntennaOffset != nil {
		antennaHeight = strconv.FormatFloat(*opts.AntennaOffset, 'f', -1, 64)
	}

	config := &model.Configuration{
		BaseMode: &model.BaseMode{
			BaseCoordinates: &model.BaseCoordinates{
				Accumulation: model.String("1"),
				Coordinates: []*string{
					model.String(lat),
					model.String(lon),
					model.String(alt),
				},
				AntennaOffset: &model.AntennaOffset{
					East:  model.String("0"),
					North: model.String("0"),
					Up:    model.String(antennaHeight),
				},
				Format: model.BaseCoordinatesFormatLLH,
				Mode:   model.BaseCoordinatesModeManual,
			},
		},
	}

	result, _, err := o.ApplyConfiguration(ctx, config)
	if err != nil {
		return errors.New("configuration update failed")
	}

	if result != configurationApplySuccess {
		return errors.New("configuration update failed")
	}

	return nil
}

const (
	eventGetReachViewVersion     = "get reachview version"
	eventReachViewVersionResults = "current reachview version"
)

type reachViewVersion struct {
	Version string `json:"version"`
	Stable  bool   `json:"bool"`
}

// Version implements protocol.Operations.
func (o *Operations) Version(ctx context.Context) (string, bool, error) {
	res := &reachViewVersion{}
	if err := o.ReqResp(ctx, eventGetReachViewVersion, nil, eventReachViewVersionResults, res); err != nil {
		return "", false, err
	}

	return strings.TrimSpace(res.Version), res.Stable, nil
}

var _ protocol.Operations = &Operations{}