// vim: shiftwidth=4 tabstop=4 noexpandtab

package main

import (
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"net"
	"net/textproto"
	"bufio"
)

type IpcServer struct {
	connections map[string]net.Conn
	listener net.Listener
}

func NewIpcServer() IpcServer {
	return IpcServer{
		connections: make(map[string]net.Conn),
	}
}

func (ipc *IpcServer) Run(ipcSocket string) {
	log.Println("Running IPC server")
	var err error
	ipc.listener,err = net.Listen("unix", ipcSocket)
	if err != nil {
		log.Fatal(err)
	}
	for {
		connection,err := ipc.listener.Accept()
		if err != nil {
			log.Print(err)
		}
		bufioreader := bufio.NewReader(connection)
		tpreader := textproto.NewReader(bufioreader)
		line,err := tpreader.ReadLine()
		log.Printf("IPC: '%s'", line)
		ipc.connections[line] = connection
		go ipc.HandleConnection(line)
	}
}

func (ipc *IpcServer) HandleConnection(connection string) {
	for {
		msg := ipc.ReadLineFrom(connection)
		if msg != "" {
			log.Printf("Got IPC message '%s' from '%s'", msg, connection)
			if connection == "picamera" {
				camera.statemachine.SendEvent(msg)
			}
		}
	}
}

func (ipc *IpcServer) WriteLineTo(connection string, line string) {
	conn := ipc.connections[connection]
	_,err := conn.Write([]byte(line))
	if err != nil {
		log.Print(err)
	}
}

func (ipc *IpcServer) ReadLineFrom(connection string) string {
	conn := ipc.connections[connection]
	bufioreader := bufio.NewReader(conn)
	tpreader := textproto.NewReader(bufioreader)
	line,_ := tpreader.ReadLine()
	return line
}

func (ipc *IpcServer) Cleanup() {
	log.Println("Releasing IPC socket ...")
	for _,connection := range ipc.connections {
		connection.Close()
	}
	ipc.listener.Close()
}

func PicameraSubprocess(ipcSocket string) {
	var cmd *exec.Cmd
	if config.Flag.Debug {
		pwd,err := os.Getwd()
		if err != nil {
			log.Fatal(err)
		}
		repoDir := filepath.Dir(pwd)
		pythonPackage := repoDir + "/python/birdscan"
		cmd = exec.Command("python3", pythonPackage, "--debug", "-s", ipcSocket)
	} else {
		cmd = exec.Command("python3", "/usr/lib/python3.9/site-packages/birdscan/", "-s", ipcSocket)
	}
	log.Println("Starting picamera service")
	err := cmd.Run()
	log.Println("picamera service terminated!")
	if err != nil {
		log.Print(err)
	}
}