package iscsit

import "bytes"

func (m *ISCSICommand) loginRespBytes() []byte {
	// rfc7143 11.13
	buf := &bytes.Buffer{}
	// byte 0
	buf.WriteByte(byte(OpLoginResp))
	var b byte
	if m.Transit {
		b |= 0x80
	}
	if m.Cont {
		b |= 0x40
	}
	b |= byte(m.CSG&0xff) << 2
	b |= byte(m.NSG & 0xff)
	// byte 1
	buf.WriteByte(b)

	b = 0
	buf.WriteByte(b)                                     // version-max
	buf.WriteByte(b)                                     // version-active
	buf.WriteByte(b)                                     // ahsLen
	buf.Write(MarshalUint64(uint64(len(m.RawData)))[5:]) // data segment length, no padding
	buf.Write(MarshalUint64(m.ISID)[2:])
	buf.Write(MarshalUint64(uint64(m.TSIH))[6:])
	buf.Write(MarshalUint64(uint64(m.TaskTag))[4:])
	buf.WriteByte(b)
	buf.WriteByte(b)
	buf.WriteByte(b)
	buf.WriteByte(b) // "reserved"
	buf.Write(MarshalUint64(uint64(m.StatSN))[4:])
	buf.Write(MarshalUint64(uint64(m.ExpCmdSN))[4:])
	buf.Write(MarshalUint64(uint64(m.MaxCmdSN))[4:])
	buf.WriteByte(byte(m.StatusClass))
	buf.WriteByte(byte(m.StatusDetail))
	buf.WriteByte(b)
	buf.WriteByte(b) // "reserved"
	var bs [8]byte
	buf.Write(bs[:])
	rd := m.RawData
	for len(rd)%4 != 0 {
		rd = append(rd, 0)
	}
	buf.Write(rd)
	return buf.Bytes()
}

type Stage int

const (
	SecurityNegotiation         Stage = 0
	LoginOperationalNegotiation       = 1
	FullFeaturePhase                  = 3
)

func (s Stage) String() string {
	switch s {
	case SecurityNegotiation:
		return "Security Negotiation"
	case LoginOperationalNegotiation:
		return "Login Operational Negotiation"
	case FullFeaturePhase:
		return "Full Feature Phase"
	}
	return "Unknown Stage"
}