package hook

import (
	"encoding/ascii85"
	"errors"
	"tunnel/pkg/netstring"
	"tunnel/pkg/server/env"
	"tunnel/pkg/server/opts"
	"tunnel/pkg/server/queue"
)

type b85Hook struct{}

func (b85Hook) Send(rq, wq queue.Q) error {
	e := netstring.NewEncoder(wq.Writer())

	for b := range rq {
		out := make([]byte, ascii85.MaxEncodedLen(len(b)))
		n := ascii85.Encode(out, b)
		e.Encode(string(out[:n]))
	}

	return nil
}

func (b85Hook) Recv(rq, wq queue.Q) error {
	d := netstring.NewDecoder(rq.Reader())

	for {
		s, err := d.Decode()
		if err != nil {
			return err
		}

		out := make([]byte, 4*len(s))

		if n, m, err := ascii85.Decode(out, []byte(s), true); err != nil {
			return err
		} else if m != len(s) {
			return errors.New("decode fail: partial consumption")
		} else {
			wq <- out[:n]
		}
	}
}

func (h b85Hook) Open(env.Env) (interface{}, error) {
	return h, nil
}

func newB85Hook(opts.Opts, env.Env) (hook, error) {
	return b85Hook{}, nil
}

func init() {
	register("b85", newB85Hook)
}