package main

import (
	"crypto/rand"
	"encoding/base64"
	"fmt"
	"log"
	"net/http"
	"runtime"

	"github.com/google/uuid"
	"golang.org/x/crypto/argon2"
)

func main() {
	// Ensure we use all available cores for maximum performance
	numCPU := runtime.NumCPU()
	runtime.GOMAXPROCS(numCPU)
	log.Printf("Server starting with %d CPU cores available", numCPU)

	// Setup routes
	http.HandleFunc("/", benchmarkHandler)

	// Start server
	log.Println("Benchmark API server listening on :5001")
	if err := http.ListenAndServe(":5001", nil); err != nil {
		log.Fatalf("Server failed to start: %v", err)
	}
}

func benchmarkHandler(w http.ResponseWriter, r *http.Request) {
	// Generate a new UUID for this request
	id := uuid.New()

	// Generate a random salt
	salt := make([]byte, 16)
	if _, err := rand.Read(salt); err != nil {
		http.Error(w, "Failed to generate salt", http.StatusInternalServerError)
		return
	}

	// Run expensive Argon2id hashing operation
	// Parameters chosen to be computationally expensive
	// - time: 3 iterations (higher values increase computation time)
	// - memory: 64 MB (higher values increase memory usage)
	// - threads: 4 (adjust based on testing, too high might cause contention)
	// - key length: 32 bytes
	hash := argon2.IDKey([]byte(id.String()), salt, 3, 64*1024, 4, 32)
	hashStr := base64.StdEncoding.EncodeToString(hash)

	// Return the result
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)
	fmt.Fprintf(w, `{"uuid":"%s","hash":"%s"}`, id, hashStr)
}