# builtins
import os
import datetime
import uuid

# third-party
import click
import flask
import OpenSSL as openssl

# internals
from application import app

import util
import database
import admin

# utility functions

def show_model(value):

    if value is None:
        return None
    return value.__name__

# cli endpoints (i.e. commands and groups)

@app.cli.command()
def install():

    models = []

    for cls in database.Model.__class_descendants__.values():

        if not cls in app.models_abstract:
            models.append(cls)

    with click.progressbar(models, label="Creating tables…", item_show_func=show_model) as models:
        for cls in sorted(models, key=lambda x: x.__class_created__):
            cls.create_table()

@app.cli.command()
def cron():

    with click.progressbar(app.cron_functions, label="Running cron functions:", item_show_func=lambda f:f.__name__ if f else '') as cron_functions:

        for func in cron_functions:
            try:
                func()
            except Exception as e:
                click.secho(f"Cron function {func} failed to run: {str(e)}", fg='red')

cli_user = flask.cli.AppGroup('user')

@cli_user.command('list')
def user_list():

    for user in admin.User.select():

        click.secho(user.name, bold=True)

        stmt = admin.ClientCert.select().where(admin.ClientCert.user == user)
        count = len(stmt)

        for i, cert in enumerate(stmt):
            if i == (count - 1):
                char_list = '└'
            else:
                char_list = '├'
            click.echo(f"{char_list} {cert.name}: " +click.style(cert.fingerprint, fg='green'))

@cli_user.command('create')
@click.argument('name')
@click.argument('password')
def user_create(name, password):

    try:
        user = admin.User.register(name, password)

    except Exception as e:
        click.secho("Could not create user, exception was as follows:", fg='red')
        click.echo(str(e))
    else:
        click.secho(f"Created user '{name}' (#{user.id}).", fg='green')

@cli_user.command('edit')
@click.argument('name')
def user_edit(name):

    try:
        user = admin.User.load(name)

    except admin.User.DoesNotExist:
        click.secho(f"User '{name}' does not exist!", fg='red')
        raise click.Abort()

    password = click.prompt("New password", hide_input=True, confirmation_prompt=True)
    click.echo(f"pw: {password}")

    if user.update_password(password):
        click.secho(f"Password for user '{name}' successfully updated.", fg='green')
    else:
        click.secho(f"Could not update password.", fg='red')

@cli_user.command('delete')
@click.argument('name')
@click.option('--yes', is_flag=True, prompt='Really delete user?')
def user_delete(name, yes):

    if not yes:
        click.secho("No opt-in, doing nothing.", fg='yellow')
        raise click.Abort()

    try:
        user = admin.User.load(name)

    except admin.User.DoesNotExist:
        click.secho(f"User '{name}' does not exist!", fg='red')
        raise click.Abort()

    if user.delete_instance():
        click.secho(f"Successfully deleted user '{name}'.", fg='green')
    else:
        click.secho(f"Could not delete user '{name}'.", fg='red')

cli_clientcert = flask.cli.AppGroup('clientcert')

@cli_clientcert.command('create')
@click.argument('username')
@click.argument('certname')
#@click.option('--not-after', default=None) # probably requires datetime?
def cert_create(username, certname):

    try:
        user = admin.User.load(username)

    except admin.User.DoesNotExist:
        click.secho(f"User '{username}' does not exist", fg='red')
        raise click.Abort()


    not_after = datetime.datetime.utcnow() + app.config['CLIENTCERT_MAX_LIFETIME']

    try:
        pkcs12 = user.gen_keypair_and_clientcert(certname, not_after)

    except Exception:

        if app.debug:
            raise

        click.secho("Client certificate creation failed.", fg='red')
        raise click.Abort()

    passphrase = util.random_string_light()

    filename = f'{username}-{certname}.p12'
    fd = open(filename, 'wb')
    fd.write(pkcs12.export(passphrase=passphrase))
    fd.close()

    cert_info = admin.ClientCert()
    cert_info.user = user
    cert_info.name = certname
    cert_info.fingerprint = pkcs12.get_certificate().digest('sha512').replace(b':', b'')
    cert_info.save(force_insert=True)

    click.secho(f"Bundled keypair and cert saved as '{filename}'.", fg='green')
    click.echo("Passphrase: " + click.style(passphrase, bold=True, fg='yellow', bg='black'))

@cli_clientcert.command('assign')
@click.argument('username')
@click.argument('certname')
@click.argument('fingerprint')
def cert_assign(username, certname, fingerprint):

    try:
        user = admin.User.load(username)

    except admin.User.DoesNotExist:
        click.secho(f"User '{username}' does not exist", fg='red')
        raise click.Abort()

    cert_info = admin.ClientCert()
    cert_info.user = user
    cert_info.name = certname
    cert_info.fingerprint = fingerprint

    if cert_info.save():
        click.secho(f"Assigned certificate fingerprint to user '{username}'.", fg='green')
    else:
        click.secho("Could not assign fingerprint.", fg='red')

@cli_clientcert.command('revoke')
@click.argument('username')
@click.argument('certname')
def cert_revoke(username, certname):

    # TODO: CRL - add entry and host the CRL itself somewhere

    try:
        user = admin.User.load(username)

    except admin.User.DoesNotExist:
        click.secho(f"User '{username}' does not exist", fg='red')
        raise click.Abort()

    try:
        cert_info = admin.ClientCert().get((admin.ClientCert.user == user) & (admin.ClientCert.name == certname))

    except admin.ClientCert.DoesNotExist:
        click.secho(f"Client certificate '{certname}' for user '{username}' does not exist.", fg='red')
        raise click.Abort()

    if cert_info.delete_instance():
        click.secho(f"Successfully deleted assignment of certificate '{certname}' to user '{username}'.", fg='green')
    else:
        click.secho(f"Could not delete client certificate assignment.", fg='red')

cli_ca = flask.cli.AppGroup('ca')

@cli_ca.command('create')
@click.option('--lifetime', prompt="How long should this CA live (in seconds, 0 means infinite)?", default=0)
def ca_create(lifetime):

    if os.path.exists('ca'):
        click.secho("Directory 'ca' already exists, move or delete it and re-run.", fg='red')
        raise click.Abort()

    click.echo("Generating keypair…")

    keypair = openssl.crypto.PKey()
    keypair.generate_key(openssl.crypto.TYPE_RSA, app.config['CLIENTCERT_KEYLENGTH'])

    click.echo("Generating certificate…")

    cert = openssl.crypto.X509()
    cert.set_serial_number(uuid.uuid4().int) # random uuid, mathmatically ~guaranteed to be unique
    issuer = cert.get_issuer()
    issuer.commonName = app.config['SITE_NAME']
    issuer.C = 'AQ'
    issuer.L = 'Free Nation Of Radiant Dissent'
    issuer.O = 'Erisian Liberation Front'
    issuer.OU = 'Cyber Confusion Center'
    cert.set_subject(issuer)
    cert.set_pubkey(keypair)
    cert.gmtime_adj_notBefore(0)

    if lifetime == 0:
        cert.set_notAfter(b'99991231235959Z') # "indefinitely valid" as defined in RFC 5280 4.1.2.5.

    else:
        cert.gmtime_adj_notAfter(lifetime)

    extensions = [
        openssl.crypto.X509Extension(b'basicConstraints', True, b'CA:TRUE, pathlen:0'),
        openssl.crypto.X509Extension(b'keyUsage', True, b'digitalSignature, keyEncipherment, dataEncipherment, keyAgreement, keyCertSign, cRLSign'),
    ]

    cert.add_extensions(extensions)

    # sign cert with private key
    cert.sign(keypair, "sha512")

    click.echo("Creating directory…")
    os.mkdir('ca')

    click.echo("Saving certificate…")
    cert_pem = openssl.crypto.dump_certificate(openssl.crypto.FILETYPE_PEM, cert)

    fd = open(os.path.join('ca', 'cert.pem'), 'w')
    fd.write(cert_pem.decode('ascii'))
    fd.close()
    del fd

    click.echo("Saving keypair…")
    key_pem = openssl.crypto.dump_privatekey(openssl.crypto.FILETYPE_PEM, keypair)

    fd = open(os.path.join('ca', 'key.pem'), 'w')
    fd.write(key_pem.decode('ascii'))
    fd.close()
    del fd

    click.secho("All done!", fg='green')

cli_user.add_command(cli_clientcert)
app.cli.add_command(cli_user)

app.cli.add_command(cli_ca)