#!/usr/bin/env python3
import requests
import subprocess
import sys
import os
import argparse
import shlex


def launch(command, data):
    if isinstance(command, str):
        command = [command]
    elif isinstance(command, tuple):
        command = list(command)
    elif not isinstance(command, list):
        raise ValueError("`command` must be `list`, `tuple`, or `str`")

    return subprocess.run(command, input=data)


def yn(question, options="yn"):
    options = options.lower()

    options_display = f"[{'/'.join(options)}]"
    full_question = f"{question} {options_display} "

    response = "WILL NEVER OCCUR IN OPTIONS"
    while not response in options:
        response = input(full_question).lower().strip()[0]

    return response


parser = argparse.ArgumentParser(
    description="Securely run a script from the Internet"
)
parser.add_argument("url", help="URL of the script")
parser.add_argument(
    "-i",
    "--interpreter",
    help="Choose interpreter to use (default: `bash`)",
    default="bash",
)
group = parser.add_mutually_exclusive_group()
group.add_argument(
    "-p",
    "--pager",
    help="Choose pager to use (default: `less`)",
    default="less",
)
group.add_argument(
    "-s",
    "--skip-pager",
    action="store_true",
    help="Skip pager and confirmation; run script immediately",
)
group.add_argument(
    "-q",
    "--quiet",
    action="store_true",
    help="Skip pager and confirmation; run script immediately; do not print anything",
)
args = parser.parse_args()
url = args.url
pager = shlex.split(args.pager)
interpreter = shlex.split(args.interpreter)

while True:
    if not args.quiet:
        print(f"Downloading `{url}`...")

    response = requests.get(url, allow_redirects=False)

    if response.status_code == 200:
        content = response.content
        break

    else:
        try:
            print(f"{response.status_code} {response.reason} (redirect to `{response.headers['location']}`)")
            if yn("Do you want to follow this redirect?") == 'y':
                url = response.headers['location']
            else:
                print("Not redirecting.")
                sys.exit(0)
        except KeyError:
            print(f"Download failed: {response.status_code} {response.reason}")
            sys.exit(0)

if not args.quiet:
    print("Download successful.")
    print("=" * os.get_terminal_size().columns)

if args.skip_pager or args.quiet:
    launch(interpreter, content)
else:
    launch(pager, content)

    response = yn("Do you want to run this script?")
    if response == "y":
        print("=" * os.get_terminal_size().columns)
        launch(interpreter, content)
    else:
        print("=" * os.get_terminal_size().columns)
        print("Script not run.")