package main

import (
	"encoding/json"
	"image"
	"io/ioutil"
	"log"
	"net/http"
	"path/filepath"
	"text/template"

	"gocv.io/x/gocv"
)

// Server is the main application struct
type Server struct {
	Streams map[string]Stream
}

func (server Server) index(w http.ResponseWriter, r *http.Request) {
	if r.FormValue("URL") == "" {
		indexTemplate, err := template.ParseFiles(filepath.Join("templates", "index.html"))
		if err != nil {
			log.Fatal(err)
		}
		indexTemplate.Execute(w, nil)
		return
	}
	URL := r.FormValue("URL")
	stream, exists := server.Streams[URL]
	if !exists {
		stream = NewStream(URL)
		server.Streams[URL] = stream
		go stream.Update()
	}
	streamTemplate, err := template.ParseFiles(filepath.Join("templates", "stream.html"))

	if err != nil {
		log.Fatal(err)
	}

	streamTemplate.Execute(w, stream)
}

func (server Server) stream(w http.ResponseWriter, r *http.Request) {
	if r.FormValue("URL") == "" {
		return
	}
	w.Header().Set("Content-Type", "image/jpeg")
	URL := r.FormValue("URL")

	stream, exists := server.Streams[URL]
	if !exists {
		return
	}

	mat := stream.GetStreamInstant()

	diff := gocv.NewMat()
	mat.CopyTo(&diff)
	gocv.CvtColor(diff, &diff, gocv.ColorBGRAToGray)
	gocv.GaussianBlur(diff, &diff, image.Point{X: 21, Y: 21}, 0, 0, gocv.BorderReflect)

	go stream.SaveStreamInstant(mat)

	if stream.PreviousInstantPathExists() {
		previous := stream.IMReadPrevious()

		gocv.GaussianBlur(previous, &previous, image.Point{X: 21, Y: 21}, 0, 0, gocv.BorderReflect)

		gocv.AbsDiff(previous, diff, &diff)

		gocv.Threshold(diff, &diff, 25, 255, gocv.ThresholdBinary)
	}

	jpg, err := gocv.IMEncode(".jpg", mat)
	if err != nil {
		log.Fatal("Could not encode Mat to jpg:", URL)
	}
	w.Write(jpg)
}

func main() {
	staticFileServer := http.FileServer(http.Dir("./static"))
	http.Handle("/static/", http.StripPrefix("/static/", staticFileServer))

	server := Server{
		Streams: make(map[string]Stream),
	}
	streams, err := ioutil.ReadDir(GetStreamDirPath())
	if err != nil {
		log.Fatal("Could not read Streamdir")
	}
	for _, streamStoreDir := range streams {
		if !streamStoreDir.IsDir() {
			continue
		}

		streamJSONPath := filepath.Join(GetStreamDirPath(), streamStoreDir.Name(), "stream.json")
		streamJSONFile, _ := ioutil.ReadFile(streamJSONPath)
		stream := Stream{}
		json.Unmarshal([]byte(streamJSONFile), &stream)
		server.Streams[stream.URL] = stream
		go stream.UpdateInterval()
	}

	http.HandleFunc("/", server.index)
	http.HandleFunc("/stream", server.stream)
	log.Fatal(http.ListenAndServe(":8080", nil))
}