package zwavejs

import (
	"context"
	"database/sql"
	"encoding/json"
	"errors"
	"fmt"
	"net"
	"sync"
	"time"

	"github.com/failsafe-go/failsafe-go"
	"github.com/failsafe-go/failsafe-go/retrypolicy"
	"github.com/google/uuid"
	"github.com/gorilla/websocket"
	"github.com/sirupsen/logrus"

	"git.janky.solutions/finn/lockserver/db"
)

type Client struct {
	Server string

	conn          *websocket.Conn
	callbacks     map[string]chan Result
	callbacksLock sync.Mutex
}

func New(server string) (*Client, error) {
	c := &Client{
		Server:    server,
		callbacks: make(map[string]chan Result),
	}
	return c, nil
}

func (c *Client) DialAndListen(ctx context.Context) {
	// Retry on ErrConnecting up to 3 times with a 1 second delay between attempts
	connectRetryPolicy := retrypolicy.Builder[*websocket.Conn]().
		WithBackoff(time.Second, time.Minute).
		Build()

	for {
		logrus.WithField("server", c.Server).Info("connecting to zwave-js server")
		conn, err := failsafe.Get(func() (*websocket.Conn, error) {
			conn, _, err := websocket.DefaultDialer.DialContext(ctx, c.Server, nil)
			return conn, err
		}, connectRetryPolicy)
		if err != nil {
			logrus.WithError(err).Fatal("error connecting to zwavejs server")
		}
		c.conn = conn
		logrus.Info("connected to zwave-js server")

		if err := c.listen(ctx); err != nil {
			if errors.Is(err, net.ErrClosed) {
				return
			}

			logrus.WithError(err).Error("error communicating with zwavejs server")
			time.Sleep(time.Second * 5)
			continue
		}
		_ = c.conn.Close()
	}
}

func (c *Client) listen(ctx context.Context) error {
	for {
		var msg IncomingMessage
		// err := c.conn.ReadJSON(&msg)
		// if err != nil {
		// 	return err
		// }

		_, rawmsg, err := c.conn.ReadMessage()
		if err != nil {
			return err
		}

		if err = json.Unmarshal(rawmsg, &msg); err != nil {
			return err
		}

		logrus.WithField("type", msg.Type).Debug("received message from zwave-js")

		switch msg.Type {
		case "version":
			if err := c.conn.WriteJSON(OutgoingMessage{Command: CommandStartListening}); err != nil {
				return err
			}

		case "result":
			if msg.MessageID == "" {
				if err := syncState(ctx, *msg.Result); err != nil {
					return fmt.Errorf("error syncing state from zwavejs server: %v", err)
				}
			} else {
				c.handleCallback(msg.MessageID, *msg.Result)
			}

		case "event":
			if err := handleEvent(ctx, *msg.Event); err != nil {
				logrus.WithError(err).Error("error handling event")
			}

		default:
			logrus.WithField("type", msg.Type).Warn("received unexpected message type from zwave-js server")
		}
	}
}

func (c *Client) Shutdown() error {
	return c.conn.Close()
}

func syncState(ctx context.Context, result Result) error {
	queries, dbc, err := db.Get()
	if err != nil {
		return err
	}
	defer dbc.Close()

	for _, node := range result.State.Nodes {
		slots := make(map[int]db.LockCodeSlot)
		lockID := int64(-1)
		for _, value := range node.Values {
			if value.CommandClass != CommandClassUserCode {
				continue
			}

			slotNumber := value.PropertyKey.Int

			lockID = int64(node.NodeID)

			slot := slots[slotNumber] // check if there's an existing entry
			slot.Slot = int64(slotNumber)

			switch Property(value.PropertyName.String) {
			case PropertyUserCode:
				slot.Code = value.Value.String
			case PropertyUserIDStatus:
				slot.Enabled = value.Value.Int > 0
			}

			slots[slotNumber] = slot
		}

		if len(slots) == 0 || lockID < 0 {
			continue
		}

		lock, err := queries.GetLockByDeviceID(ctx, lockID)
		if err != nil {
			if errors.Is(err, sql.ErrNoRows) {
				lock, err = queries.CreateLock(ctx, lockID)
			}

			if err != nil {
				return err
			}
		}

		for _, slot := range slots {
			err := queries.UpsertCodeSlot(ctx, db.UpsertCodeSlotParams{
				Lock:    lock.ID,
				Code:    slot.Code,
				Slot:    slot.Slot,
				Enabled: slot.Enabled,
			})
			if err != nil {
				return fmt.Errorf("error upserting slot: %v", err)
			}
		}
	}

	return nil
}

func handleEvent(ctx context.Context, event Event) error {
	if event.Source != EventSourceNode || event.Event != EventTypeNotification {
		return nil
	}

	queries, dbc, err := db.Get()
	if err != nil {
		return err
	}
	defer dbc.Close()

	lock, err := queries.GetLockByDeviceID(ctx, int64(event.NodeID))
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return nil
		}
		return fmt.Errorf("error getting lock: %v", err)
	}

	code := sql.NullInt64{}
	if event.Parameters.UserID > 0 {
		slot, err := queries.GetLockCodeBySlot(ctx, db.GetLockCodeBySlotParams{
			Lock: lock.ID,
			Slot: int64(event.Parameters.UserID),
		})
		if err != nil {
			return fmt.Errorf("error getting code slot: %v", err)
		}
		code = sql.NullInt64{
			Int64: slot.ID,
			Valid: true,
		}
	}

	err = queries.AddLogEntry(ctx, db.AddLogEntryParams{
		Lock:  lock.ID,
		Code:  code,
		State: event.NotificationLabel,
	})
	if err != nil {
		return fmt.Errorf("error adding log entry: %v", err)
	}

	logrus.WithFields(logrus.Fields{
		"lock":  lock.ID,
		"code":  code,
		"state": event.NotificationLabel,
	}).Debug("processed lock event")

	return nil
}

func (c *Client) handleCallback(messageID string, result Result) error {
	c.callbacksLock.Lock()
	defer c.callbacksLock.Unlock()

	cb, ok := c.callbacks[messageID]
	if !ok {
		logrus.WithField("message_id", messageID).Warn("got response to a message we didn't send")
		return nil
	}

	// TODO: set a timeout
	cb <- result
	return nil
}

func (c *Client) sendMessage(message OutgoingMessageIface) (Result, error) {
	messageID := uuid.New().String()
	message.SetMessageID(messageID)

	ch := make(chan Result)

	c.callbacksLock.Lock()
	c.callbacks[messageID] = ch
	c.callbacksLock.Unlock()

	if err := c.conn.WriteJSON(message); err != nil {
		return Result{}, err
	}

	result := <-ch

	close(ch)

	c.callbacksLock.Lock()
	delete(c.callbacks, messageID)
	c.callbacksLock.Unlock()

	return result, nil
}

func (c *Client) SetNodeValue(ctx context.Context, nodeID int, valueID NodeValue, value AnyType) error {
	msg := NodeSetValueMessage{
		OutgoingMessage: OutgoingMessage{Command: CommandNodeSetValue},
		NodeID:          nodeID,
		ValueID:         valueID,
		Value:           value,
	}
	result, err := c.sendMessage(&msg)
	if err != nil {
		return err
	}

	if !result.Success {
		return errors.New("non-successful response from zwave-js server")
	}

	return nil
}