package imapx

import (
	"net"
	"time"
)

// idleReadTimeout bounds how long a connection may go WITHOUT receiving any
// bytes from the server before the read is aborted. It is an *idle* timeout,
// not a total deadline: every successful read pushes it forward, so a slow but
// live transfer never trips it — only a genuinely dead/mute socket does. This
// is what stops an account from wedging in "running" forever when a server
// accepts a command (e.g. a large FETCH) and then goes silent.
var idleReadTimeout = 60 * time.Second

// idleConn wraps a net.Conn and arms a fresh read deadline before every Read.
// It lives beneath any TLS layer (the raw TCP conn), so the deadline governs
// the actual blocking network read regardless of encryption.
type idleConn struct {
	net.Conn
	timeout time.Duration
}

func (c *idleConn) Read(b []byte) (int, error) {
	if c.timeout > 0 {
		// Ignore the error: a closed conn will surface it from Read below.
		_ = c.Conn.SetReadDeadline(time.Now().Add(c.timeout))
	}
	return c.Conn.Read(b)
}