import hashlib
import hmac
import json
import os
import subprocess
import threading

import flask

HOST = os.getenv("WEBHOOK_HOST", "0.0.0.0")
PORT = os.getenv("WEBHOOK_PORT", 6000)

CONFIG_FILE = os.getenv("CONFIG_FILE", "./test/config.json")

app = flask.Flask(__name__)


class HttpError(Exception):
    def __init__(self, status, msg):
        self.status = status
        self.msg = msg


def _load_config():
    with open(CONFIG_FILE) as f:
        return json.load(f)


@app.route("/<user>/<repo>/deploy", methods=['POST'])
def deploy(user, repo):
    try:
        response = _deploy(user, repo)
        status = 200
    except HttpError as e:
        response = e.msg
        status = e.status
    except Exception:
        response = "Internal Error"
        status = 500
        raise
    return flask.Response(response, status=status)


def _deploy(user, repo):
    payload = flask.request.json
    repo_full_name = payload['repository']['full_name']

    if repo_full_name != '/'.join([user, repo]):
        raise HttpError(400, "Endpoint doesn't match repository")

    config = _load_config().get(user, {}).get(repo)
    if not config:
        raise HttpError(400, f"Configuration not found for {user}/{repo}")

    secret = config['secret'].encode('utf-8')
    signature = hmac.new(secret, flask.request.data, hashlib.sha256).hexdigest()
    h_signature = flask.request.headers.get('X-Gitea-Signature')

    if h_signature != signature:
        raise HttpError(403, "Unauthorized: Signatures don't match")

    th = threading.Thread(target=_deploy_script, kwargs=dict(config=config))
    th.setDaemon(True)
    th.start()

    return "OK"


def _deploy_script(config):
    print("Running deploy script ...")
    cmd = [config['deploy_script']]
    subprocess.call(cmd, env=config.get('env'))
    print("Deployed!")


def run():
    app.run(host=HOST, port=PORT, debug=True)


if __name__ == '__main__':
    run()