package middleware

import (
	"encoding/json"
	"net/http"
)

func Auth(expectedClientID, expectedAPIKey string, next http.HandlerFunc) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		clientID := r.Header.Get("Client-Id")
		apiKey := r.Header.Get("Api-Key")

		if clientID == "" || apiKey == "" {
			writeError(w, 401, "missing credentials: Client-Id and Api-Key headers are required")
			return
		}

		if expectedClientID != "" && clientID != expectedClientID {
			writeError(w, 403, "invalid client id")
			return
		}
		if expectedAPIKey != "" && apiKey != expectedAPIKey {
			writeError(w, 403, "invalid api key")
			return
		}

		next(w, r)
	}
}

func writeError(w http.ResponseWriter, code int, msg string) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(code)
	json.NewEncoder(w).Encode(map[string]any{
		"code":    code,
		"message": msg,
	})
}