package main

import (
	"bufio"
	"crypto/tls"
	"os"
	"sync"

	"go.lindenii.runxiyu.org/lindenii-common/scfg"
)

var config struct {
	Server_name string            `scfg:"server_name"`
	Routes      map[string]string `scfg:"routes"`
	TLS         struct {
		Cert string `scfg:"cert"`
		Key  string `scfg:"key"`
	} `scfg:"tls"`
	_tls_config *tls.Config
}
var config_mutex sync.RWMutex

func load_config(path string) error {
	config_file, err := os.Open(path)
	if err != nil {
		return err
	}
	decoder := scfg.NewDecoder(bufio.NewReader(config_file))
	if func() error {
		config_mutex.Lock()
		defer config_mutex.Unlock()
		err = decoder.Decode(&config)
		if err != nil {
			return err
		}
		cer, err := tls.LoadX509KeyPair(config.TLS.Cert, config.TLS.Key)
		if err != nil {
			return err
		}
		config._tls_config = &tls.Config{
			Certificates: []tls.Certificate{cer},
			MinVersion: tls.VersionTLS13,
		}
		return nil
	}() != nil {
		return err
	}
	return nil
}

// config_fetch_one fetches one value from the configuration.
//
// Consequtive calls do not guarantee a consistent snapshot of the
// configuration. Use config_consistent_run in these cases.
func config_fetch_one[T any](x *T) T {
	config_mutex.RLock()
	defer config_mutex.RUnlock()
	return *x
}

// config_consistent_run runs the supplied function with a consistent snapshot
// of the configuration.
func config_consistent_run(f func()) {
	config_mutex.RLock()
	defer config_mutex.RUnlock()
	f()
}