#!/usr/bin/env python3

import os
import subprocess
import sys
import time
import venv

from io import FileIO
from threading import Thread


# Variables ############################################################################################################

usage = f"""
{sys.argv[0]} <sub-command> <options>*

    This script will perform various activities related to building this
    package and managing tests, development servers, etc.  It provides the
    follow sub-commands:

        init : initialize the virtual environment for this package in the
            ./usr directory. This includes making a copy of Python, Pip,
            and installing any dependencies specified in requirements.txt.
            It allows the following options:

            --clear : Remove any existing ./usr directory before initialization

        generate : generate HTML/CSS/JS for the site from the raw source files

        server : run a local server which serves up a copy of the website as it
            will be shown on GitHub pages

"""

DATA_FILE = "data.yaml"

command = None
clear = False

project_root = os.path.dirname(os.path.abspath(sys.argv[0]))
docs_dir = os.path.join(project_root, "docs")
src_dir = os.path.join(project_root, "src")
template_dir = os.path.join(src_dir, "templates")
venv_dir = os.path.join(project_root, "usr")
bin_dir = os.path.join(venv_dir, "bin")

activate = os.path.join(bin_dir, "activate")
pip = os.path.join(bin_dir, "pip")
python = os.path.join(bin_dir, "python")
requirements_file = os.path.join(project_root, "requirements.txt")


# Helper Functions #####################################################################################################

def shell(*args, **kwargs):
    kwargs["shell"] = True
    return subprocess.run(*args, **kwargs)


# Command Functions ####################################################################################################

def command_generate():
    os.makedirs(docs_dir, exist_ok=True)
    shell(f"cp -R {src_dir}/images {docs_dir}/")
    shell(f"{python} src/generate_styles.py {src_dir} {docs_dir}")
    shell(f"{python} src/generate.py {template_dir} {src_dir} {docs_dir}")


def command_init():
    builder = venv.EnvBuilder(clear=clear, symlinks=False, with_pip=True)
    builder.create(venv_dir)

    shell(f"{pip} install --upgrade pip")
    shell(f"{pip} install -r {requirements_file}")


def command_python():
    shell(f"{python}")


def command_server():
    server_func = lambda: shell(f"cd {docs_dir} && {python} -m http.server 8080")
    thread = Thread(target=server_func, daemon=True)
    thread.start()

    while True:
        command_generate()
        time.sleep(2)


# Startup Script #######################################################################################################

if __name__ == "__main__":
    if sys.version_info < (3, 5):
        print(f"Python {sys.version} provided, but at least version 3.5 is required.")
        sys.exit(1)

    for arg in sys.argv[1:]:
        if arg == "generate":
            command = command_generate
        elif arg == "init":
            command = command_init
        elif arg == "python":
            command = command_python
        elif arg == "server":
            command = command_server
        elif arg == "--clear":
            clear = True
        else:
            print(f"{usage}\nUnexpected argument: {arg}\n")
            sys.exit(1)

    if command is not None:
        try:
            command()
        except KeyboardInterrupt:
            print("\nCancelled.")
    else:
        print(f"{usage}\nPlease choose a subcommand.\n")