package main

import (
	"log"
	"os"
	"path"

	"github.com/fsnotify/fsnotify"
	"github.com/mkideal/cli"
)

func stop() {
	log.Println("Have a nice day.")
	// TODO: Make the error code optional (as a parameter)
	os.Exit(1)
}

func waitAndExecuteCommandsFromDevice() {
	// TODO: Establish connection to the device
	// TODO: Wait for action loop
	// TODO: Execute action
	// TODO: Wait for action loop ...
}

func watchForConfigChanges(configFile string) {
	watcher, err := fsnotify.NewWatcher()
	if err != nil {
		log.Fatal(err)
	}
	defer watcher.Close()

	done := make(chan bool)
	go func() {
		for {
			select {
			case event := <-watcher.Events:
				// The file is changed. This is the only event we are interested
				// in. If the file is renamed, removed or something else, we drop
				// an error to the user.
				if event.Op&fsnotify.Write == fsnotify.Write {
					log.Println("Reload the config file ...")
					// TODO: Parse the config file
					// TODO: Handle errors in the config file
					// TODO: Write a mapping for the mapping of the keys to the binary format the avr wants.
					// TODO: Establish a connection to the device
					// TODO: Transfer the new key mappings
					// TODO: Close the connection?
				}

				if event.Op&fsnotify.Rename == fsnotify.Rename ||
					event.Op&fsnotify.Remove == fsnotify.Remove {
					log.Println("The configuration file is renamed or removed. We cant do any further changes without the config file. So create the file or rename it back and restart the agent.")
					stop()
				}
			case err := <-watcher.Errors:
				log.Println("We have the following problem with the configuration file: ", err)
				log.Println("Try the fix this problem by yourself and restart the agent.")
				stop()
			}
		}
	}()

	err = watcher.Add(configFile)
	if err != nil {
		log.Fatal("Can't find the configuration file. Please create one.")
	}
	<-done
}

type argT struct {
	cli.Helper
	ConfigFile string `cli:"c,config" usage:"specify a keymap config file"`
}

func main() {
	configPath, _ := os.Getwd()
	configFile := path.Join(configPath, "keymap.conf")

	cli.Run(&argT{}, func(ctx *cli.Context) error {
		args := ctx.Argv().(*argT)
		if args.ConfigFile != "" {
			configFile = args.ConfigFile
		}

		if !args.Help {
			// Start up the application
			log.Println("Using the configuration file", configFile)
			watchForConfigChanges(configFile)
			waitAndExecuteCommandsFromDevice()

			stop()
		}

		return nil
	})
}