package server

import (
	"context"
	"fmt"
	"net/http"
	"time"

	"github.com/modelcontextprotocol/go-sdk/mcp"
	log "github.com/nacorid/logger"
	"github.com/nacorid/naco-api/internal/utils"
)

type MetricsMiddleware struct {
	requestsBucket utils.RollingStats
	totalRequests  utils.Counter
}

func NewMetricsHook() *MetricsMiddleware {
	return &MetricsMiddleware{
		requestsBucket: *utils.NewRollingStats(60, 1*time.Second),
		totalRequests:  *utils.NewCounter(),
	}
}

func (mh *MetricsMiddleware) OnCall(next mcp.MethodHandler) mcp.MethodHandler {
	return func(ctx context.Context, method string, request mcp.Request) (mcp.Result, error) {
		if method == "tools/call" {
			start := time.Now()
			mh.requestsBucket.Increment()
			mh.totalRequests.Increment()
			result, err := next(ctx, method, request)
			duration := fmt.Sprintf("%.2fms", float64(time.Since(start))/float64(time.Millisecond))
			log.DebugWithContext(ctx, "MetricsMiddleware: MCP Handler", "duration", duration)
			return result, err
		}
		return next(ctx, method, request)
	}
}

func (mh *MetricsMiddleware) OnCallHTTP(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		start := time.Now()
		mh.requestsBucket.Increment()
		mh.totalRequests.Increment()
		next.ServeHTTP(w, r)
		duration := fmt.Sprintf("%.2fms", float64(time.Since(start))/float64(time.Millisecond))
		log.DebugWithContext(r.Context(), "MetricsMiddleware: HTTP Handler", "duration", duration)
	})
}

func (mh *MetricsMiddleware) GetRPS() float64 {
	return mh.requestsBucket.GetRPS()
}

func (mh *MetricsMiddleware) GetTotalRequests() int64 {
	return mh.totalRequests.Get()
}