package ircconn

import (
	"bufio"
	"context"
	"io"
	"log/slog"
	"sync"

	"github.com/valyala/bytebufferpool"
	"tuxpa.in/a/irc/pkg/ircdecoder"
	"tuxpa.in/a/irc/pkg/ircv3"
)

type Conn struct {
	w       io.Writer
	r       io.Reader
	muWrite sync.Mutex
}

func New(w io.Writer, r io.Reader) *Conn {
	return &Conn{
		w: w,
		r: r,
	}
}

// while serve is running, the conn owns the reader.
func Serve(ctx context.Context, r io.Reader, wr ircv3.MessageWriter, h ircv3.Handler) error {
	h.Handle(wr, ircv3.NewEvent(ctx, ircv3.EventTypeCONTROL, ircv3.NewMessage("/EVENT_ON_SERVE")))
	dec := &ircdecoder.Decoder{}
	r = bufio.NewReaderSize(r, 10240)
	for {
		select {
		case <-ctx.Done():
			return ctx.Err()
		default:
		}
		msg := &ircv3.Message{}
		r = io.LimitReader(r, 8191+512)
		err := dec.Decode(r, msg)
		if err != nil {
			return err
		}
		h.Handle(wr, ircv3.NewEvent(ctx, ircv3.EventTypeIRC, msg))
	}
}

type MessageWriter struct {
	R   io.Writer
	Log *slog.Logger
	mu  sync.Mutex
}

func (r *MessageWriter) WriteMessage(msg *ircv3.Message) error {
	b := bytebufferpool.Get()
	defer bytebufferpool.Put(b)
	err := msg.Encode(b)
	if err != nil {
		return err
	}
	if r.Log != nil {
		r.Log.Info("out >", "msg", msg.String())
	}
	b.WriteString("\r\n")
	r.mu.Lock()
	defer r.mu.Unlock()
	_, err = r.R.Write(b.B)
	if err != nil {
		return err
	}
	return nil
}