package main

import (
  "github.com/fsnotify/fsnotify"
  "flag"
  "log"
  "os"
  "encoding/json"
  "time"
  "path/filepath"
)

type Cert struct {
  PrivateKey string
  PublicKey string
  Owner string
}

type Config struct {
  Source Cert
  Target Cert
  Reload string
  WatchDelay string
  watcher *fsnotify.Watcher
  delay_time time.Duration
}

func LoadConfig(path string) Config {
  var config Config

  config_data, err := os.ReadFile(path)
  if err != nil {
    log.Fatal("invalid config path %s: %v", path, err)
  }

  err = json.Unmarshal(config_data, &config)
  if err != nil {
    log.Fatal(err, "json format error")
  }

  config.delay_time, err = time.ParseDuration(config.WatchDelay)
  if err != nil {
    log.Fatalf("can't parse watch_delay setting %s: %v", config.WatchDelay, err)
  }

  return config
}

func ParseOpts() Config {
  var config_file string

  flag.StringVar(&config_file, "config", "cert-bouncer.json", ".json config to use.")
  flag.Parse()

  return LoadConfig(config_file)
}

func (cfg *Config) SyncCerts() {
  log.Println("SYNC CERTS CALLED");
}

func (cfg *Config) HandleEvents() {
  doit := time.NewTimer(cfg.delay_time)
  doit.Stop()

  for { 
    select {
    case event, ok := <-cfg.watcher.Events:
      if !ok {
        return
      }

      log.Println("EVENT", event)

      if event.Name == cfg.Source.PrivateKey {
        doit.Reset(cfg.delay_time)
      }
    case <-doit.C:
      cfg.SyncCerts()
    case err, ok := <-cfg.watcher.Errors:
      if !ok {
        return
      }

      log.Println("failed to watch", err)
    }
  }
}

func (cfg *Config) WatchFiles() {
  var err error

  cfg.watcher, err = fsnotify.NewWatcher()
  if err != nil {
    log.Fatal(err, "Can't watch files.")
  }
  defer cfg.watcher.Close()

  go cfg.HandleEvents()

  cfg.Source.PrivateKey, err = filepath.Abs(cfg.Source.PrivateKey)
  if err != nil {
    log.Fatalf("can't convert %s to absolut path: %v",
      cfg.Source.PrivateKey, err)
  }

  err = cfg.watcher.Add(cfg.Source.PrivateKey)
  if err != nil {
    log.Fatalf("can't watch %s: %v", err, cfg.Source.PrivateKey)
  }

  <-make(chan struct{})
}

func main() {
  config := ParseOpts()
  config.WatchFiles()
}