/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

package notify

import (
	"fmt"
	"strings"

	"git.st8l.com/luxolus/kdnotify/schema/notify/prio"
	"git.st8l.com/luxolus/kdnotify/schema/notify/state"
	"git.st8l.com/luxolus/kdnotify/schema/notify/ty"
)

// Keepalived VRRP notify message
type VrrpMessage struct {
	Message
}

// Parse the given line of text into a VrrpMessage if possible,
// erroring out if not.
func ParseVrrp(line string) (VrrpMessage, error) {
	msg, err := ParseMessage(line)
	if err != nil {
		return VrrpMessage{}, fmt.Errorf("unable parse message from '%s': %w", line, err)
	}

	vrrp, err := NewVrrp(msg)
	if err != nil {
		return vrrp, fmt.Errorf("unable parse vrrp from '%s': %w", line, err)
	}

	return vrrp, nil
}

// Upgrade a Message into a VrrpMessage that is guaranteed to be a valid VRRP message
func NewVrrp(m Message) (VrrpMessage, error) {
	var v VrrpMessage

	if !m.Type.IsVRRP() {
		return v, fmt.Errorf("'%s' is not a valid VRRP message type", m.Type.String())
	}

	if m.State == state.UNKNOWN {
		return v, fmt.Errorf("unknown VRRP message state")
	}

	v.Type = m.Type
	v.Instance = m.Instance
	v.State = m.State
	v.Priority = m.Priority

	return v, nil
}

// Keepalived notify message
type Message struct {
	Type     ty.Type
	Instance string
	State    state.State
	Priority prio.Priority
}

// Create a new Message from its components
func New(t ty.Type, instance string, s state.State, p prio.Priority) Message {
	return Message{
		Type:     t,
		Instance: instance,
		State:    s,
		Priority: p,
	}
}

// Parse a line into a Message, erroring out if the line format is invalid
func ParseMessage(line string) (Message, error) {
	var m Message

	line = strings.TrimSpace(line)
	// $TYPE $INSTANCE $STATE $PRIORITY $REST...
	pt := strings.SplitN(line, " ", 5)
	l := len(pt)

	// Priority is optional
	if l < 3 {
		return m, fmt.Errorf("unable to parse message from '%s': not enough fields", line)
	}

	m.Type = ty.ParseType(pt[0])
	m.Instance = pt[1]
	m.State = state.ParseState(pt[2])
	if l > 3 {
		m.Priority = prio.ParsePriority(pt[3])
	}

	return m, nil
}