// Package metrics 定义 Prometheus 监控指标。
package metrics

import (
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promauto"
)

var (
	// SearchTotal 按 provider 统计搜索请求总数。
	SearchTotal = promauto.NewCounterVec(
		prometheus.CounterOpts{
			Name: "bowen_search_total",
			Help: "Total search requests by provider.",
		},
		[]string{"provider"},
	)

	// SearchDuration 搜索请求耗时直方图。
	SearchDuration = promauto.NewHistogram(
		prometheus.HistogramOpts{
			Name:    "bowen_search_duration_seconds",
			Help:    "Search request duration in seconds.",
			Buckets: prometheus.DefBuckets,
		},
	)

	// SearchErrors 按原因统计搜索错误。
	SearchErrors = promauto.NewCounterVec(
		prometheus.CounterOpts{
			Name: "bowen_search_errors_total",
			Help: "Search errors by reason.",
		},
		[]string{"reason"},
	)

	// CacheHits 缓存命中总数。
	CacheHits = promauto.NewCounter(
		prometheus.CounterOpts{
			Name: "bowen_cache_hits_total",
			Help: "Total cache hits.",
		},
	)

	// CacheMisses 缓存未命中总数。
	CacheMisses = promauto.NewCounter(
		prometheus.CounterOpts{
			Name: "bowen_cache_misses_total",
			Help: "Total cache misses.",
		},
	)

	// CacheHitsL2 Redis 二级缓存命中数。
	CacheHitsL2 = promauto.NewCounter(
		prometheus.CounterOpts{
			Name: "bowen_cache_hits_l2_total",
			Help: "L2 (Redis) cache hits.",
		},
	)

	// ActiveKeys 各 provider 的活跃密钥数。
	ActiveKeys = promauto.NewGaugeVec(
		prometheus.GaugeOpts{
			Name: "bowen_active_keys",
			Help: "Number of active API keys by provider.",
		},
		[]string{"provider"},
	)
)