package dispatcher

import "log"
import "time"
import "os"
import "fmt"
import "net/url"
import "udi/mqtt"
import "udi/config"
import "udi/counter"
import "udi/handlers/handler"
import "udi/handlers/ttn"
import "udi/handlers/iot"
import "udi/handlers/pv"
import "udi/handlers/mbgw3"
import "udi/handlers/sver"
import "udi/handlers/svej"
import "udi/handlers/dt1t"
import "udi/handlers/locative"
import "udi/handlers/prepared"
import "udi/handlers/z2m"


var handlerMap map[string]handler.Handler = make(map[string]handler.Handler)
var archiverChannel chan handler.MessageT = make(chan handler.MessageT, 100)

func InitDispatcher() {
  log.Printf("Dispatcher initializing")
  go archiver()

  for _, mapping := range config.Config.TopicMappings {
    // log.Printf("Trying to initialize %s", mapping)

    var factory interface{}
    switch mapping.Handler {
    case "TTN":
      factory = ttn.New
    case "IoT":
      factory = iot.New
    case "PV":
      factory = pv.New
    case "MBGW3":
      factory = mbgw3.New
    case "SVER":
      factory = sver.New
    case "SVEJ":
      factory = svej.New
    case "DT1T":
      factory = dt1t.New
    case "Locative":
      factory = locative.New
    case "PREP":
      factory = prepared.New
    case "Z2M":
      factory = z2m.New
    default:
      factory = nil
      log.Printf("No handler %s found, ignore mapping", mapping.Handler)
    }

    fn, ok := factory.(func(string, config.HandlerConfigT) handler.Handler)
    if ! ok {
      log.Println("Typ Assertion failed")
      break
    }
    handler := fn(mapping.Id, mapping.Config)
    handlerMap[mapping.Id] = handler
  }

  //log.Printf("handlerMap: %s", handlerMap)
}

func storeMessage(filename string, item handler.MessageT) {
  file, err := os.OpenFile(filename, os.O_APPEND | os.O_CREATE | os.O_WRONLY, 0644)
  if err != nil {
    log.Printf("Unable to open archiving file %s, message is not archived: %s", filename, err)
    counter.F("Archived")
    return
  }
  defer file.Close()
  archivingString := fmt.Sprintf("%s - %s - %s\n", item.Timestamp.Format("2006-01-02 15:04:05"), item.Topic, item.Payload)
  _, err = file.WriteString(string(archivingString) + "\n")
  if err != nil {
    log.Printf("Unable to write message, message is not archived: %s", err)
    counter.F("Archived")
    return
  }
  //log.Println("Successfully archived message")
  counter.S("Archived")
}

func archiver() {
  archivingRootDir := config.Config.Archiver.Dir
  var lastArchivingDir string

  for {
    select {
    case message := <- archiverChannel:
      currentDateStr := message.Timestamp.Format("2006/01/02/15")
      currentArchivingDir := archivingRootDir + "/" + currentDateStr
      if currentArchivingDir != lastArchivingDir {
        err := os.MkdirAll(currentArchivingDir, 0755)
        if err != nil {
          log.Printf("Unable to create archiving dir %s: %s", currentArchivingDir, err)
          counter.F("Archived")
        }
        lastArchivingDir = currentArchivingDir
        //log.Printf("Archiving dir %s created", currentArchivingDir)
      }
      archivingFilename := fmt.Sprintf("%s/%s", currentArchivingDir, url.PathEscape(message.Topic))
      storeMessage(archivingFilename, message)
    }
  }
}

func InputDispatcher() {
  for {
    select {
    case mqttMessage := <- mqtt.InputChannel:
      //log.Printf("Message arrived in inputDispatcher, topic: %s\n", mqttMessage.Topic)
      message := handler.MessageT { time.Now(), mqttMessage.Topic, string(mqttMessage.Payload) }
      archiverChannel <- message
      handleMessage(message)
    }
  }
}

func handleMessage(message handler.MessageT) {
  for _, mapping := range config.Config.TopicMappings {
    // log.Printf("Testing %s -> %s", mapping.Topics, mapping.Handler)
    for _, subscribedTopic := range mapping.Topics {
      // log.Printf("Testing %s in %s", message.Topic, subscribedTopic)
      if mqtt.TopicMatchesSubscription(message.Topic, subscribedTopic) {
        //log.Printf("Handle message in handler %s", mapping.Id)
        handler, exists := handlerMap[mapping.Id]
        if exists {
          handler.Handle(message)
          counter.S("Dispatched")
          return
        } else {
          log.Printf("Handler %s not found, message %s is lost", mapping.Id, message)
          counter.F("Dispatched")
        }
      }
    }
  }
  log.Printf("No match for topic %s, message %s is lost", message.Topic, message)
  counter.F("Dispatched")
}