package main

import (
	"fmt"
	"github.com/fsnotify/fsnotify"
	"gopkg.in/yaml.v2"
	"io/ioutil"
	"log"
	"os"
	//	"time"
)

// parse a request file and return a SCORSHmessage
func parseRequest(fname string, msg *spoolMsg) error {

	debug.log("[parseRequest] message at start: %s\n", msg)

	data, err := ioutil.ReadFile(fname)
	if err != nil {
		log.Printf("Unable to open file: %s\n", fname)
		return SCORSHerr(errNoFile)
	}

	debug.log("[parseRequest] file contains: \n%s\n", data)

	debug.log("[parseRequest] reading message from file: %s\n", fname)

	err = yaml.Unmarshal([]byte(data), msg)
	if err != nil {
		return fmt.Errorf("Error parsing message: %s", err)
	}
	debug.log("[parseRequest] got message: %s\n", msg)
	return nil
}

func spooler(watcher *fsnotify.Watcher, master chan spoolMsg) {

	log.Println("Spooler started correctly")

	for {
		select {
		case event := <-watcher.Events:
			// Here we manage genuine events from fsnotify. We catch the
			// "Write" event, which should happen only when the file is
			// created
			if event.Op == fsnotify.Write {
				var msg spoolMsg
				debug.log("[spooler] new file %s detected\n", event.Name)
				err := parseRequest(event.Name, &msg)
				if err != nil {
					log.Printf("Invalid packet received. [%s]\n", err)
				}
				debug.log("[spooler] read message: %s\n", msg)
				msg.Path = event.Name
				master <- msg
			}
		case err := <-watcher.Errors:
			// here we manage event errors
			log.Println("[spooler] error: ", err)
		case msg := <-master:
			// Here we receive messages from the master about files to be
			// removed
			log.Printf("[spooler] received deletion request for: %s\n", msg.Path)
			err := os.Remove(msg.Path)
			if err != nil {
				log.Printf("[spooler] error removing file: %s\n", err)
			} else {
				log.Printf("[spooler] file %s successfully removed\n", msg.Path)
			}
		}
	}
}

func startSpooler(master *master) error {

	watcher, err := fsnotify.NewWatcher()

	if err != nil {
		return fmt.Errorf("error creating watcher: %s", err)
	}

	err = watcher.Add(master.Spooldir)
	if err != nil {
		return fmt.Errorf("error adding folder: %s", err)
	}

	go spooler(watcher, master.Spooler)

	return nil
}