// vim: shiftwidth=4 tabstop=4 noexpandtab

package main

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

type Camera struct {
	statemachine Machine
}

func NewCamera() Camera {
	return Camera{
		statemachine: Machine{
			name: "camera",
			initial: "idle",
			states: StateMap{
				"idle": MachineState{
					on: TransitionMap{
						"take_single_picture": MachineTransition{
							to: "single_picture",
						},
					},
				},
				"single_picture": MachineState{
					on: TransitionMap{
						"single_picture_taken": MachineTransition{
							to: "idle",
						},
					},
				},
			},
			api: make(chan string),
			state_listeners: make([]*(chan string), 0),
			hook: runCameraHooks,
		},
	}
}

func runCameraHooks(last string, next string, m *Machine) {
	if last == "idle" && next == "single_picture" {
		go singlePicture(m)
	}
}

func singlePicture(m *Machine) {

	// create command
	var cmd *exec.Cmd
	if !config.Flag.Debug {
		cmd = exec.Command("/usr/bin/python3", "/usr/lib/python3.9/site-packages/birdscan/")
	} else {  // debug mode
		pwd,err := os.Getwd()
		if err != nil {
			log.Fatal(err)
		}
		repoDir := filepath.Dir(pwd)
		log.Printf("Repository path is assumed to be = '%s'", repoDir)
		pythonPackage := repoDir + "/python/birdscan"
		cmd = exec.Command("/usr/bin/python3", pythonPackage, "--debug")
	}

	// connect stdout of python process
	stdout,err := cmd.StdoutPipe()
	if err != nil {
		log.Print(err)
	}
	defer stdout.Close()

	// run command
	err = cmd.Start()
	if err != nil {
		log.Print(err)
	}

	scanner := bufio.NewScanner(stdout)
	for scanner.Scan() {
		text := scanner.Text()
		log.Printf("Python returned '%s'", text)
		if text == "ok" {
			break
		}
	}

	err = cmd.Wait()  // wait until command execution and io is complete
	if err != nil {
		log.Print(err)
	}

	// process result
	m.SendEvent("single_picture_taken")
}

func (cam *Camera) run() {
	cam.statemachine.Run()
}

// read until '\n'
func readLine(buff *[]byte, ) {

}