package monitoring

import (
	"time"

	"github.com/prometheus/client_golang/prometheus"
)

// MetricsCollector 提供更简洁的指标收集API
type MetricsCollector struct {
	writeTotal           prometheus.Counter
	queryTotal           prometheus.Counter
	writeLatency         prometheus.Histogram
	queryLatency         prometheus.Histogram
	activeConnections    prometheus.Gauge
	dataPointsCount      prometheus.Gauge
	persistenceLatency   prometheus.Histogram
	persistenceErrors    prometheus.Counter
	messagingLatency     prometheus.Histogram
	messagingErrors      prometheus.Counter
	websocketConnections prometheus.Gauge
}

// NewMetricsCollector 创建一个新的指标收集器
func NewMetricsCollector() *MetricsCollector {
	return &MetricsCollector{
		writeTotal: prometheus.NewCounter(prometheus.CounterOpts{
			Name: "gotidb_write_total",
			Help: "Total number of write operations",
		}),
		queryTotal: prometheus.NewCounter(prometheus.CounterOpts{
			Name: "gotidb_query_total",
			Help: "Total number of query operations",
		}),
		writeLatency: prometheus.NewHistogram(prometheus.HistogramOpts{
			Name:    "gotidb_write_latency_seconds",
			Help:    "Write operation latency in seconds",
			Buckets: prometheus.DefBuckets,
		}),
		queryLatency: prometheus.NewHistogram(prometheus.HistogramOpts{
			Name:    "gotidb_query_latency_seconds",
			Help:    "Query operation latency in seconds",
			Buckets: prometheus.DefBuckets,
		}),
		activeConnections: prometheus.NewGauge(prometheus.GaugeOpts{
			Name: "gotidb_active_connections",
			Help: "Number of active connections",
		}),
		dataPointsCount: prometheus.NewGauge(prometheus.GaugeOpts{
			Name: "gotidb_data_points_count",
			Help: "Number of data points in the database",
		}),
		persistenceLatency: prometheus.NewHistogram(prometheus.HistogramOpts{
			Name:    "gotidb_persistence_latency_seconds",
			Help:    "Persistence operation latency in seconds",
			Buckets: prometheus.DefBuckets,
		}),
		persistenceErrors: prometheus.NewCounter(prometheus.CounterOpts{
			Name: "gotidb_persistence_errors_total",
			Help: "Total number of persistence errors",
		}),
		messagingLatency: prometheus.NewHistogram(prometheus.HistogramOpts{
			Name:    "gotidb_messaging_latency_seconds",
			Help:    "Messaging operation latency in seconds",
			Buckets: prometheus.DefBuckets,
		}),
		messagingErrors: prometheus.NewCounter(prometheus.CounterOpts{
			Name: "gotidb_messaging_errors_total",
			Help: "Total number of messaging errors",
		}),
		websocketConnections: prometheus.NewGauge(prometheus.GaugeOpts{
			Name: "gotidb_websocket_connections",
			Help: "Number of active WebSocket connections",
		}),
	}
}

// RecordWrite 记录写入操作及其延迟
func (c *MetricsCollector) RecordWrite(duration time.Duration) {
	c.writeTotal.Inc()
	c.writeLatency.Observe(duration.Seconds())
}

// RecordQuery 记录查询操作及其延迟
func (c *MetricsCollector) RecordQuery(duration time.Duration) {
	c.queryTotal.Inc()
	c.queryLatency.Observe(duration.Seconds())
}

// IncActiveConnections 增加活跃连接数
func (c *MetricsCollector) IncActiveConnections() {
	c.activeConnections.Inc()
}

// DecActiveConnections 减少活跃连接数
func (c *MetricsCollector) DecActiveConnections() {
	c.activeConnections.Dec()
}

// SetDataPointsCount 设置数据点数量
func (c *MetricsCollector) SetDataPointsCount(count float64) {
	c.dataPointsCount.Set(count)
}

// RecordPersistence 记录持久化操作及其延迟
func (c *MetricsCollector) RecordPersistence(duration time.Duration, err error) {
	c.persistenceLatency.Observe(duration.Seconds())
	if err != nil {
		c.persistenceErrors.Inc()
	}
}

// RecordMessaging 记录消息操作及其延迟
func (c *MetricsCollector) RecordMessaging(duration time.Duration, err error) {
	c.messagingLatency.Observe(duration.Seconds())
	if err != nil {
		c.messagingErrors.Inc()
	}
}

// IncWebSocketConnections 增加WebSocket连接数
func (c *MetricsCollector) IncWebSocketConnections() {
	c.websocketConnections.Inc()
}

// DecWebSocketConnections 减少WebSocket连接数
func (c *MetricsCollector) DecWebSocketConnections() {
	c.websocketConnections.Dec()
}

// Describe 实现prometheus.Collector接口
func (c *MetricsCollector) Describe(ch chan<- *prometheus.Desc) {
	c.writeTotal.Describe(ch)
	c.queryTotal.Describe(ch)
	c.writeLatency.Describe(ch)
	c.queryLatency.Describe(ch)
	c.activeConnections.Describe(ch)
	c.dataPointsCount.Describe(ch)
	c.persistenceLatency.Describe(ch)
	c.persistenceErrors.Describe(ch)
	c.messagingLatency.Describe(ch)
	c.messagingErrors.Describe(ch)
	c.websocketConnections.Describe(ch)
}

// Collect 实现prometheus.Collector接口
func (c *MetricsCollector) Collect(ch chan<- prometheus.Metric) {
	c.writeTotal.Collect(ch)
	c.queryTotal.Collect(ch)
	c.writeLatency.Collect(ch)
	c.queryLatency.Collect(ch)
	c.activeConnections.Collect(ch)
	c.dataPointsCount.Collect(ch)
	c.persistenceLatency.Collect(ch)
	c.persistenceErrors.Collect(ch)
	c.messagingLatency.Collect(ch)
	c.messagingErrors.Collect(ch)
	c.websocketConnections.Collect(ch)
}