package main

import (
	"fmt"
	"io"
	"log"
	"net"
	"sync"
	"time"
)

type PacketWithData struct {
	MessageType uint16
	Added       time.Time
	Consumed    bool
	Data        []byte
}

type PacketQueue struct {
	mu         sync.RWMutex
	Packets    []PacketWithData
	connection net.Conn
}

func NewPacketQueue(connection net.Conn) *PacketQueue {

	queue := &PacketQueue{
		Packets:    make([]PacketWithData, 0),
		connection: connection,
	}
	go func() {
		defer connection.Close()
		for {
			messageType, data, err := ReceivePacket(queue.connection)
			ts := time.Now()
			if err != nil {
				log.Printf("Error receiving packet: %v\n", err)
				if err == io.EOF {
					return
				}

				//return
			}

			queue.mu.Lock()

			l := make([]PacketWithData, 0, len(queue.Packets))

			for _, packet := range queue.Packets {
				if !packet.Consumed {
					l = append(l, packet)
				}
			}

			queue.Packets = append(l, PacketWithData{
				MessageType: messageType,
				Added:       ts,
				Data:        data,
			})
			queue.mu.Unlock()
			packetsReceived.Inc()
			packetQueue.Set(float64(len(queue.Packets)))
		}
	}()
	return queue
}

func (p *PacketQueue) Expect(messageType uint16, timeToWait time.Duration) (*PacketWithData, error) {
	start := time.Now().Add(-time.Millisecond)

	for {
		if time.Since(start) > timeToWait {
			return nil, fmt.Errorf("timeout waiting for message type %d", messageType)
		}
		p.mu.RLock()
		for _, packet := range p.Packets {
			if packet.MessageType == messageType && packet.Added.After(start) {
				packet.Consumed = true
				p.mu.RUnlock()
				return &packet, nil
			}
		}
		p.mu.RUnlock()
		time.Sleep(time.Millisecond * 2)
	}
}