package web

import (
	mqtt "github.com/mochi-mqtt/server/v2"

	mqttforwardpkg "meshtastic_mqtt_server/internal/mqttforward"
	storepkg "meshtastic_mqtt_server/internal/store"
)

// MQTTStatusProvider 是 web 层向上层要的"返回当前 mqtt broker 状态"接口；
// 实现一般由 main 包传入（持有真正的 mqtt.Server / 写队列 / 统计器）。
type MQTTStatusProvider interface {
	Status() AdminMQTTStatus
}

// MQTTRuntimeStatus 把 mqtt.Server / 写队列 / 转发统计三个上下文打包成
// 实现 MQTTStatusProvider 的具体类型。供 main 包构造后注入 newRouter。
type MQTTRuntimeStatus struct {
	Server  *mqtt.Server
	Address string
	TLS     bool
	Stats   *mqttforwardpkg.Stats
	DBQueue *storepkg.WriteQueue
}

// AdminMQTTStatus 是 admin 路由 GET /admin/mqtt-status 返回的 JSON 视图。
type AdminMQTTStatus struct {
	Running             bool              `json:"running"`
	Address             string            `json:"address"`
	TLS                 bool              `json:"tls"`
	Version             string            `json:"version"`
	Started             int64             `json:"started"`
	Uptime              int64             `json:"uptime"`
	BytesReceived       int64             `json:"bytes_received"`
	BytesSent           int64             `json:"bytes_sent"`
	ClientsConnected    int64             `json:"clients_connected"`
	ClientsDisconnected int64             `json:"clients_disconnected"`
	ClientsMaximum      int64             `json:"clients_maximum"`
	ClientsTotal        int64             `json:"clients_total"`
	MessagesReceived    int64             `json:"messages_received"`
	MessagesSent        int64             `json:"messages_sent"`
	MessagesDropped     int64             `json:"messages_dropped"`
	DBWriteQueueLength  int               `json:"db_write_queue_length"`
	Retained            int64             `json:"retained"`
	Inflight            int64             `json:"inflight"`
	InflightDropped     int64             `json:"inflight_dropped"`
	Subscriptions       int64             `json:"subscriptions"`
	PacketsReceived     int64             `json:"packets_received"`
	PacketsSent         int64             `json:"packets_sent"`
	Clients             []AdminMQTTClient `json:"clients"`
}

type AdminMQTTClient struct {
	ClientID   string `json:"client_id"`
	Username   string `json:"username"`
	Listener   string `json:"listener"`
	RemoteAddr string `json:"remote_addr"`
	RemoteHost string `json:"remote_host"`
	RemotePort string `json:"remote_port"`
}

// Status 实现 MQTTStatusProvider。
func (m MQTTRuntimeStatus) Status() AdminMQTTStatus {
	if m.Server == nil || m.Server.Info == nil {
		return AdminMQTTStatus{Running: false, Address: m.Address, TLS: m.TLS, DBWriteQueueLength: m.DBQueue.Len()}
	}
	info := m.Server.Info.Clone()
	status := AdminMQTTStatus{
		Running:             true,
		Address:             m.Address,
		TLS:                 m.TLS,
		Version:             info.Version,
		Started:             info.Started,
		Uptime:              info.Uptime,
		BytesReceived:       info.BytesReceived,
		BytesSent:           info.BytesSent,
		ClientsConnected:    info.ClientsConnected,
		ClientsDisconnected: info.ClientsDisconnected,
		ClientsMaximum:      info.ClientsMaximum,
		ClientsTotal:        info.ClientsTotal,
		MessagesReceived:    info.MessagesReceived,
		MessagesSent:        m.Stats.Forwarded(),
		MessagesDropped:     m.Stats.Dropped(),
		DBWriteQueueLength:  m.DBQueue.Len(),
		Retained:            info.Retained,
		Inflight:            info.Inflight,
		InflightDropped:     info.InflightDropped,
		Subscriptions:       info.Subscriptions,
		PacketsReceived:     info.PacketsReceived,
		PacketsSent:         info.PacketsSent,
	}
	for _, client := range m.Server.Clients.GetAll() {
		if client == nil || client.Closed() {
			continue
		}
		info := mqttClientInfo(client)
		status.Clients = append(status.Clients, AdminMQTTClient{
			ClientID:   info.ClientID,
			Username:   info.Username,
			Listener:   info.Listener,
			RemoteAddr: info.RemoteAddr,
			RemoteHost: info.RemoteHost,
			RemotePort: info.RemotePort,
		})
	}
	return status
}

// 简化版客户端信息——只解析展示所需字段，避免依赖 main 包里的辅助。
type mqttClientInfoView struct {
	ClientID   string
	Username   string
	Listener   string
	RemoteAddr string
	RemoteHost string
	RemotePort string
}

func mqttClientInfo(c *mqtt.Client) mqttClientInfoView {
	if c == nil {
		return mqttClientInfoView{}
	}
	info := mqttClientInfoView{
		ClientID:   c.ID,
		Username:   string(c.Properties.Username),
		Listener:   c.Net.Listener,
		RemoteAddr: c.Net.Remote,
	}
	host, port := splitHostPort(c.Net.Remote)
	info.RemoteHost = host
	info.RemotePort = port
	return info
}

func splitHostPort(addr string) (string, string) {
	if addr == "" {
		return "", ""
	}
	// 复用 net.SplitHostPort，但要兼容 "host" 这种没端口的情况。
	for i := len(addr) - 1; i >= 0; i-- {
		if addr[i] == ':' {
			host := addr[:i]
			if len(host) >= 2 && host[0] == '[' && host[len(host)-1] == ']' {
				host = host[1 : len(host)-1]
			}
			return host, addr[i+1:]
		}
	}
	return addr, ""
}