from abc import ABC, abstractmethod

class logger(ABC):
    def __init__(self):
        pass
    
    @abstractmethod
    def info(self, content):    
        pass

    @abstractmethod
    def warning(self, content):
        pass

    @abstractmethod
    def error(self, content):
        pass

class stdio_logger(logger): 
    def info(self, content):
        print("[INFO]: " + str(content))

    def warning(self, content):
        print("[WARNING]: " + str(content))

    def error(self, content):
        print("[ERROR]: " + str(content))

class dummy_logger(logger):
    def info(self, content):
        pass

    def warning(self, content):
        pass

    def error(self, content):
        pass

class file_logger(logger):
    def __init__(self, file):
        try:
            self.file = open(file, "w")
        except:
            print("Can not open log file: \"" + file + "\"")
            exit(-1)

    def __del__(self):
        self.file.close()

    def info(self, content):
        try:
            self.file.write("[INFO]: " + str(content) + "\n")
        except:
            print("Can not write to log file!")
            exit(-1)

    def warning(self, content): 
        try:
            self.file.write("[WARNING]: " + str(content) + "\n")
        except:
            print("Can not write to log file!")
            exit(-1)

    def error(self, content):   
        try:
            self.file.write("[ERROR]: " + str(content) + "\n")
        except:
            print("Can not write to log file!")
            exit(-1)

class loader:
    _logger = None

    def get():
        if loader._logger is None:
            Exception("Logger bust be set in loader first.")

        return loader._logger

    def set(new_logger):
        if type(new_logger) is not logger:
            Exception("New loader must be instance of logger.")
        
        loader._logger = new_logger

    def __init__(self):
        Exception("Loader is static class.")