// Command he-dydns updates Hurricane Electric dynamic DNS entries.
package main

import (
	"fmt"
	"log"
	"os"
	"os/signal"
	"strings"
	"syscall"
	"time"

	"git.aehoo.net/alphard/he-dydns/internal/config"
	"git.aehoo.net/alphard/he-dydns/internal/updater"
)

func main() {
	log.SetFlags(log.LstdFlags)

	daemon := false
	configPath := ""

	args := os.Args[1:]
	for i := 0; i < len(args); i++ {
		arg := args[i]
		switch {
		case arg == "daemon":
			daemon = true
		case arg == "-h" || arg == "--help" || arg == "help":
			usage()
			return
		case arg == "--config" || arg == "-config":
			i++
			if i >= len(args) {
				fmt.Fprintf(os.Stderr, "%s requires a path argument\n", arg)
				usage()
				os.Exit(2)
			}
			configPath = args[i]
		case strings.HasPrefix(arg, "--config="):
			configPath = strings.TrimPrefix(arg, "--config=")
		case strings.HasPrefix(arg, "-config="):
			configPath = strings.TrimPrefix(arg, "-config=")
		default:
			fmt.Fprintf(os.Stderr, "unknown argument: %s\n", arg)
			usage()
			os.Exit(2)
		}
	}

	if configPath == "" {
		var err error
		configPath, err = config.DefaultPath()
		if err != nil {
			log.Fatalf("fatal: %v", err)
		}
	}

	cfg, err := config.Load(configPath)
	if err != nil {
		log.Fatalf("fatal: %v", err)
	}

	runErr := updater.Run(cfg)
	if runErr != nil {
		log.Printf("update pass completed with errors: %v", runErr)
	}

	if !daemon {
		if runErr != nil {
			os.Exit(1)
		}
		return
	}

	interval := time.Duration(cfg.IntervalMinutes) * time.Minute
	log.Printf("entering daemon mode, updating every %d minute(s)", cfg.IntervalMinutes)

	ticker := time.NewTicker(interval)
	defer ticker.Stop()

	sigCh := make(chan os.Signal, 1)
	signal.Notify(sigCh, os.Interrupt, syscall.SIGTERM)

	for {
		select {
		case <-ticker.C:
			if err := updater.Run(cfg); err != nil {
				log.Printf("update pass completed with errors: %v", err)
			}
		case sig := <-sigCh:
			log.Printf("received %s, shutting down", sig)
			return
		}
	}
}

func usage() {
	defaultPath := "~/.config/he-dydns/config.toml"
	if p, err := config.DefaultPath(); err == nil {
		defaultPath = p
	}

	fmt.Fprintln(os.Stderr, "usage: he-dydns [--config path] [daemon]")
	fmt.Fprintf(os.Stderr, "  --config path  load configuration from path instead of %s\n", defaultPath)
	fmt.Fprintln(os.Stderr, "  (no args)      run one update pass and exit")
	fmt.Fprintln(os.Stderr, "  daemon         run one update pass, then repeat on the configured interval")
}