package metrics

import (
	"net/http"

	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promhttp"
	"github.com/zeromicro/go-zero/core/logx"
)

const namespace = "muyu"
const subsystem = "inventory"

// ---- Business Counters ----

var ProductCreatedTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
	Namespace: namespace, Subsystem: subsystem,
	Name: "product_created_total",
	Help: "Total number of products created.",
}, []string{"tenant_id", "product_name", "spec", "color"})

var ProductDeletedTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
	Namespace: namespace, Subsystem: subsystem,
	Name: "product_deleted_total",
	Help: "Total number of products deleted (soft delete).",
}, []string{"tenant_id"})

var ImportOperationsTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
	Namespace: namespace, Subsystem: subsystem,
	Name: "import_operations_total",
	Help: "Total number of import operations executed.",
}, []string{"tenant_id", "operator"})

var ImportProductsTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
	Namespace: namespace, Subsystem: subsystem,
	Name: "import_products_total",
	Help: "Total number of products processed during imports.",
}, []string{"tenant_id", "result"})

var InboundLengthMetersTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
	Namespace: namespace, Subsystem: subsystem,
	Name: "inbound_length_meters_total",
	Help: "Total length (meters) of fabric added to inventory.",
}, []string{"tenant_id", "product_name", "color", "operation"})

var InboundBoltsTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
	Namespace: namespace, Subsystem: subsystem,
	Name: "inbound_bolts_total",
	Help: "Total number of bolt records added to inventory.",
}, []string{"tenant_id", "operation"})

var PansSavedTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
	Namespace: namespace, Subsystem: subsystem,
	Name: "pans_saved_total",
	Help: "Total number of pan-save operations.",
}, []string{"tenant_id", "product_id"})

var StockCheckCreatedTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
	Namespace: namespace, Subsystem: subsystem,
	Name: "stock_check_created_total",
	Help: "Total number of stock check records created.",
}, []string{"tenant_id"})

var StockCheckConfirmedTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
	Namespace: namespace, Subsystem: subsystem,
	Name: "stock_check_confirmed_total",
	Help: "Total number of stock checks confirmed.",
}, []string{"tenant_id"})

var StockAdjustCreatedTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
	Namespace: namespace, Subsystem: subsystem,
	Name: "stock_adjust_created_total",
	Help: "Total number of stock adjustments created.",
}, []string{"tenant_id", "reason"})

var StockAdjustApprovedTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
	Namespace: namespace, Subsystem: subsystem,
	Name: "stock_adjust_approved_total",
	Help: "Total number of stock adjustments approved/rejected.",
}, []string{"tenant_id", "action"})

var StockAdjustQuantityMeters = prometheus.NewCounterVec(prometheus.CounterOpts{
	Namespace: namespace, Subsystem: subsystem,
	Name: "stock_adjust_quantity_meters_total",
	Help: "Total adjusted quantity in meters (absolute value, split by direction).",
}, []string{"tenant_id", "direction"})

// ---- Histograms ----

var ImportBatchSize = prometheus.NewHistogramVec(prometheus.HistogramOpts{
	Namespace: namespace, Subsystem: subsystem,
	Name:    "import_batch_size",
	Help:    "Number of products per import operation.",
	Buckets: []float64{1, 5, 10, 50, 100, 200, 500, 1000},
}, []string{"tenant_id"})

// ---- RPC Operational Metrics ----

var RPCDurationSeconds = prometheus.NewHistogramVec(prometheus.HistogramOpts{
	Namespace: namespace, Subsystem: subsystem,
	Name:    "rpc_duration_seconds",
	Help:    "Duration of RPC calls in seconds.",
	Buckets: prometheus.DefBuckets,
}, []string{"method"})

var RPCRequestsTotal = prometheus.NewCounterVec(prometheus.CounterOpts{
	Namespace: namespace, Subsystem: subsystem,
	Name: "rpc_requests_total",
	Help: "Total number of RPC requests.",
}, []string{"method", "code"})

func init() {
	prometheus.MustRegister(
		ProductCreatedTotal,
		ProductDeletedTotal,
		ImportOperationsTotal,
		ImportProductsTotal,
		InboundLengthMetersTotal,
		InboundBoltsTotal,
		PansSavedTotal,
		StockCheckCreatedTotal,
		StockCheckConfirmedTotal,
		StockAdjustCreatedTotal,
		StockAdjustApprovedTotal,
		StockAdjustQuantityMeters,
		ImportBatchSize,
		RPCDurationSeconds,
		RPCRequestsTotal,
	)
}

func StartHTTP(addr string) {
	mux := http.NewServeMux()
	mux.Handle("/metrics", promhttp.Handler())
	go func() {
		logx.Infof("prometheus metrics listening on %s", addr)
		if err := http.ListenAndServe(addr, mux); err != nil {
			logx.Errorf("prometheus http server error: %v", err)
		}
	}()
}