#!/usr/bin/env python3
""" Script to send SMSes using the Free mobile API
"""
import sys
import logging
import argparse
import readline
import configparser
from itertools import count

import requests


class SMSApiManager:
    """ Class to manage ending SMS notification using Free Mobile API.
    """
    FREE_API_URL = "https://smsapi.free-mobile.fr/sendmsg"
    MAX_LENGTH = 999
    RETURN_CODE = {200: "Message sent",
                   400: "Mandatory parameter is missing",
                   402: "Too many SMS sent in to few time",
                   403: "Service disabled",
                   500: "Server error, please try again later"}
    def __init__(self, conf_file_path):
        self._pass = ""
        self.user_id = ""
        self.read_config(conf_file_path)

    def send_sms(self, msg: str):
        """ Send a SMS to a user using its passphrase and user ID
        Return the response object from requests.
        """
        # Make sure we do not send more than MAX_LENGTH characters
        msg = msg[:self.MAX_LENGTH]
        data = {"user": self.user_id,
                "pass": self._pass,
                "msg": msg}
        res = requests.get(self.FREE_API_URL, params=data)
        logging.info(self.RETURN_CODE[res.status_code])
        return res

    def read_config(self, conf_file_path):
        """ Read and apply the configuration from a config file.
        That config file must have a 'creds' section, and the following options:
        - 'user_id', that contains the user identifier for the API
        - 'passphrase', that contains this user's API key
        """
        conf_parser = configparser.ConfigParser()
        conf_parser.read(conf_file_path)
        self.user_id = conf_parser["creds"]["user_id"]
        self._pass = conf_parser["creds"]["passphrase"]


def parse_args():
    """ Parse the script's command line argument, and return the args object.
    """
    my_parser = argparse.ArgumentParser(description="Script to send a SMS to a person. "
                                                    "The message must be at most "
                                                    f"{SMSApiManager.MAX_LENGTH} characters long.")
    my_parser.add_argument("-c", "--config", help="Path to the config file.",
                           default="secrets.ini")
    my_parser.add_argument("message", nargs="?",
                           help="Message to send to the recipient. If no message is given, "
                                f"read up to {SMSApiManager.MAX_LENGTH} characters from the "
                                "standard input")
    my_parser.add_argument("-i", "--interactive", action="store_true",
                           help="Send messages in interactive mode "
                                "instead of from the command line.")
    return my_parser.parse_args()


def rlinput(prompt, prefill=''):
    """ Prefill the input content with the value of `prefill`
    All credits go to https://stackoverflow.com/a/2533142
    """
    readline.set_startup_hook(lambda: readline.insert_text(prefill))
    try:
        return input(prompt)
    finally:
        readline.set_startup_hook()

def main():
    """ Instantiate an sms_manager, and send SMS
    """
    args = parse_args()
    sms_manager = SMSApiManager(args.config)
    while args.interactive:
        # Interactive mode is enabled, loop indefinetely until user hits Ctrl+C or Ctrl+D
        try:
            message=[]
            for i in count():
                message.append(rlinput(f"What is your message (line {i+1})?: ",
                               prefill=args.message))
                args.message=""
                if not message[i]:
                    break
            res = sms_manager.send_sms(msg='\n'.join(message))
            if res.status_code != 200:
                print("Error while sending the message:")
            print(f"{sms_manager.RETURN_CODE[res.status_code]}")
        except (EOFError, KeyboardInterrupt):
            print("\nBye !")
            break
    else:
        # Else either get message from command line or stdin.
        logging.basicConfig(level=logging.INFO)
        if args.message:
            # Send the requested message
            sms_manager.send_sms(msg=args.message)
        else:
            # Read the message from stdin
            msg = sys.stdin.read(sms_manager.MAX_LENGTH)
            res = sms_manager.send_sms(msg=msg)

if __name__ == "__main__":
    main()