package osc

import (
	"bytes"
	"fmt"
	"net"
	"strings"
	"sync"
)

type Value struct {
	Type  byte
	Float float32
	Int   int32
	Bool  bool
	Str   string
}

type Handler func(address string, args []Value) error

type Server struct {
	addr     string
	conn     *net.UDPConn
	handlers map[string]Handler
	mu       sync.RWMutex
}

func NewServer(host string, port int) *Server {
	return &Server{
		addr:     fmt.Sprintf("%s:%d", host, port),
		handlers: map[string]Handler{},
	}
}

func (s *Server) Map(param string, h Handler) { s.handlers["/avatar/parameters/"+param] = h }
func (s *Server) Close() error                { if s.conn != nil { return s.conn.Close() }; return nil }

func (s *Server) Serve() error {
	addr, err := net.ResolveUDPAddr("udp", s.addr)
	if err != nil {
		return err
	}
	conn, err := net.ListenUDP("udp", addr)
	if err != nil {
		return err
	}
	s.conn = conn
	buf := make([]byte, 2048)
	for {
		n, _, err := conn.ReadFromUDP(buf)
		if err != nil {
			return err
		}
		a, v, err := parseMessage(buf[:n])
		if err != nil {
			continue
		}
		s.mu.RLock()
		h := s.handlers[a]
		s.mu.RUnlock()
		if h != nil {
			_ = h(a, v)
		}
	}
}

func parseMessage(b []byte) (string, []Value, error) {
	parts := bytes.SplitN(b, []byte{0}, 2)
	if len(parts) == 0 {
		return "", nil, fmt.Errorf("invalid osc")
	}
	address := string(parts[0])
	if !strings.HasPrefix(address, "/") {
		return "", nil, fmt.Errorf("invalid address")
	}
	return address, nil, nil
}