from queue import Queue
from threading import Thread
from threading import Event
from time import sleep
import sane
from PIL import Image
import sys
import os
import select
import cv2
import subprocess

def is_there_line():
    # Check if there is any data available to be read from stdin
    if select.select([sys.stdin], [], [], 0)[0]:
        # Read the next line from stdin
        return sys.stdin.readline().rstrip('\n')
    else:
        return None

class Message:
    def __init__(self, message, payload):
        self.message = message
        self.payload = payload

def interface_thread(i, o):
    queue = []
    processing = []
    scanned = []
    scanners = []
    print("<{}>$ ".format(os.getcwd()), end="")
    sys.stdout.flush()
    while True:
        line = is_there_line()
        if line:
            # parse the line of input
            splitted = line.split(' ')
            if splitted[0] == "queue":
                if splitted[1] == "add":
                    if splitted[2]:
                        if splitted[2][0] != "/":
                            enqueued = os.path.join(os.getcwd(), splitted[2])
                        else:
                            enqueued = splitted[2]
                        queue.append(enqueued)
                        print("queued file {}".format(enqueued))
                    else:
                        print("specify a file!")
            elif splitted[0] == "send":
                print("sending {} to scanner for scanning".format(queue[0]))
                payload = {
                        'save_location': queue.pop(0),
                }
                message = Message("scan_request", payload)
                o.put(message)
            elif splitted[0] == "cd":
                try:
                    os.chdir(splitted[1])
                except IndexError:
                    os.chdir("/home/usr")
            elif splitted[0] == "mkdir":
                os.mkdir(splitted[1])
            elif splitted[0] == "ls":
                files = os.listdir()
                print(files)
            elif splitted[0] == "feh":
                subprocess.Popen(["feh", splitted[1]])
            elif splitted[0] == "scannerlist":
                o.put(Message("list_scanners", None))
                data = i.get()
                if data.message == "list_scanners_resp":
                    scanners = data.payload["scanner_names"]
                for x in scanners:
                    print(x)
                i.task_done()
            elif splitted[0] == "setscanner":
                payload = {
                        "scanner_name": splitted[1],
                }
                message = Message("set_scanner", payload)
                o.put(message)
            elif splitted[0] == "sendpredef":
                o.put(Message("sendpredef", None))
            elif splitted[0] == "help":
                print("""help: commands -
queue:
    add: add an item to the queue
send: send the first item on the queue to be scanned
cd: change directories
mkdir: make a directory
ls: list files in directory
feh: open image viewer
scannerlist: list scanners connected
setscanner: set the scanner as the selected scanner
sendpredef: set the scanner to some predefined settings""")

            print("<{}>$ ".format(os.getcwd()), end="")
            sys.stdout.flush()


def scanner_backend(i, o):
    sane.init()
    scanner = None
    while True:
        # Get some data
        data = i.get()
        if data.message == "scan_request":
            save_location = data.payload['save_location']
            if scanner:
                print("recieved scan_request with {}".format(save_location))
            else:
                print("configure a scanner first")
                i.task_done()
                continue

            image = scanner.scan()
            image.save(data.payload["save_location"])

            i.task_done()
        elif data.message == "list_scanners":
            devs = sane.get_devices()
            payload = {
                    'scanner_names': [x[0] for x in devs],
            }
            message = Message("list_scanners_resp", payload)
            o.put(message)
            i.task_done()
        elif data.message == "set_scanner":
            scanner = sane.open(data.payload["scanner_name"])
            i.task_done()
        elif data.message == "sendpredef":
            # configure the scanner in these predefined ways
            scanner.resolution = 200
            scanner.br_x = 320
            scanner.br_y = 320
            scanner.calibration_cache = 1
            i.task_done()

# Create the shared queue and launch both threads
def main():
    interface_queue, scanner_queue = Queue(), Queue()
    threads = [
            Thread(target=interface_thread, args=(interface_queue, scanner_queue)),
            Thread(target=scanner_backend, args=(scanner_queue, interface_queue)),
    ]
    [ i.start() for i in threads ]

if __name__ == "__main__":
    main()