from pathlib import Path

from importing import load_module
from task import Task
from utils import printable_exception


class Module:

    def __init__(self, fname, entry):
        fname = Path(fname)
        self.fname = fname
        self.entry = entry
        self.name = fname.stem.replace("-", "_")
        self.mtime = self.get_mtime()
        self.mod = self.func = self.task = None


    def start(self):
        if not self.func:
            raise MissingEntryFunctionError

        self.task = task = Task(self.func, self.name)
        task.start()
        return task


    def kill(self):
        if self.task:
            self.task.kill()

    @property
    def is_running(self):
        if self.task:
            return self.task.is_running


    def load(self):
        try:
            self.mod = mod = load_module(self.name, self.fname)
        except Exception as e:
            raise ModuleLoadError(printable_exception(e)) from e

        try:
            self.func = getattr(mod, self.entry)
        except AttributeError as e:
            raise MissingEntryFunctionError from e


    def file_exists(self):
        return self.fname.is_file()

    def has_changed(self):
        return self.mtime != self.get_mtime()

    def get_mtime(self):
        try:
            return self.fname.stat().st_mtime
        except FileNotFoundError:
            pass

    def __str__(self):
        return f"{self.fname} -> {self.name} ({self.mtime})"



class ModuleLoadError(Exception):
    pass

class MissingEntryFunctionError(Exception):
    pass