package model

import (
	"errors"
	"strings"
)

type MqttTopic struct {
	DeptId     string
	Domain     string
	DeviceType string
	DeviceID   string
	Resource   string
}

// 从字符串解析成 MqttTopic
func FromStringToMqttTopic(topic string) *MqttTopic {
	parts := strings.Split(topic, "/")
	// 补齐不足的部分
	for len(parts) < 5 {
		parts = append(parts, "")
	}
	return &MqttTopic{
		DeptId:     parts[0],
		Domain:     parts[1],
		DeviceType: parts[2],
		DeviceID:   parts[3],
		Resource:   parts[4],
	}
}

// 从结构体生成 topic 字符串，可用 "+" 表示通配符
func (m *MqttTopic) ToString() string {
	toVal := func(s string) string {
		if s == "" {
			return "+"
		}
		return s
	}
	return strings.Join([]string{
		toVal(m.DeptId),
		toVal(m.Domain),
		toVal(m.DeviceType),
		toVal(m.DeviceID),
		toVal(m.Resource),
	}, "/")
}

// 严格生成 topic，不允许 "+" 或空
func (m *MqttTopic) Build() (string, error) {
	parts := []string{m.DeptId, m.Domain, m.DeviceType, m.DeviceID, m.Resource}
	for _, p := range parts {
		if p == "" || p == "+" {
			return "", errors.New("cannot build strict topic, wildcard exists")
		}
	}
	return strings.Join(parts, "/"), nil
}

// 判断是否为通配符 topic
func (m *MqttTopic) IsWildcard() bool {
	topic := m.ToString()
	return strings.Contains(topic, "+") || strings.Contains(topic, "#")
}