package guardianextension

import (
	"encoding/hex"
	"encoding/json"
	"os"

	"github.com/caddyserver/caddy/v2/caddyconfig/httpcaddyfile"
	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
	"github.com/twmb/murmur3"
)

// LoadData loads the map from a JSON file.
func (handler *GuardianCacheHandler) LoadData() error {
	file, err := os.Open(handler.DataFile)
	if err != nil {
		return err
	}
	defer file.Close()

	decoder := json.NewDecoder(file)
	return decoder.Decode(&handler.data)
}

// parseCaddyfile creates a new GuardianCacheHandler instance and initializes it by parsing the Caddyfile configuration.
// This function is used by Caddy to load the GuardianCacheHandler module from the Caddyfile. It's called once during init.
func parseCaddyfile(helper httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error) {
	handler := new(GuardianCacheHandler)
	err := handler.UnmarshalCaddyfile(helper.Dispenser)
	return handler, err
}

// questionHash generates a 32-byte hash string from the provided question string using the MurmurHash3 algorithm.
// The hash is encoded as a hexadecimal string and returned.
//
// Benchmarks
// cpu: Intel(R) Core(TM) i7-10750H CPU @ 2.60GHz
// BenchmarkStringSum128WithPreGeneratedData-12             6135975               179.3 ns/op
// BenchmarkSprintfWithPreGeneratedData-12                  6602058               179.9 ns/op
// BenchmarkStrconvWithPreGeneratedData-12                 10127676               123.0 ns/op
// BenchmarkBytesBufferWithPreGeneratedData-12              7616581               156.3 ns/op
// BenchmarkEncodingHexWithPreGeneratedData-12             18349746                64.95 ns/op  <----
func questionHash(question string) string {
	h1, h2 := murmur3.StringSum128(question)
	hash := hex.EncodeToString([]byte{
		byte(h1 >> 56), byte(h1 >> 48), byte(h1 >> 40), byte(h1 >> 32),
		byte(h1 >> 24), byte(h1 >> 16), byte(h1 >> 8), byte(h1),
		byte(h2 >> 56), byte(h2 >> 48), byte(h2 >> 40), byte(h2 >> 32),
		byte(h2 >> 24), byte(h2 >> 16), byte(h2 >> 8), byte(h2),
	})
	// caddy.Log().Named("guardianextension").Sugar().Debugf("questionHash: %s -> %s", question, hash)
	return hash
}