#!/usr/bin/env python3
"""Notify of drone.io CI pipeline results on Matrix chat.

Requires:

* <https://pypi.org/project/matrix-nio>
* Optional: <https://pypi.org/project/bleach/>
* Optional: <https://pypi.org/project/markdown/>

"""

import argparse
import asyncio
import fnmatch
import json
import logging
import os
import sys
from distutils.util import strtobool
from os.path import exists
from string import Template

from nio import AsyncClient, LoginResponse

PROG = "matrixchat-notify"
CONFIG_FILENAME = f"{PROG}-config.json"
DEFAULT_ALLOWED_ATTRS = {
    "*": ["class"],
    "a": ["href", "title"],
    "abbr": ["title"],
    "acronym": ["title"],
    "img": ["alt", "src"],
}
DEFAULT_ALLOWED_TAGS = {
    "a",
    "abbr",
    "acronym",
    "b",
    "blockquote",
    "code",
    "dd",
    "div",
    "dl",
    "dt",
    "em",
    "h1",
    "h2",
    "h3",
    "h4",
    "h5",
    "h6",
    "i",
    "li",
    "ol",
    "p",
    "span",
    "strong",
    "table",
    "td",
    "th",
    "thead",
    "tr",
    "ul",
}
DEFAULT_HOMESERVER = "https://matrix.org"
DEFAULT_MARKDOWN_EXTENSIONS = "admonition, extra, sane_lists, smarty"
DEFAULT_PASS_ENVIRONMENT = ["DRONE_*"]
DEFAULT_TEMPLATE = "${DRONE_BUILD_STATUS}"
SETTINGS_KEYS = (
    "allowed_tags",
    "allowed_attrs",
    "accesstoken",
    "deviceid",
    "devicename",
    "homeserver",
    "markdown",
    "markdown_extensions",
    "pass_environment",
    "password",
    "roomid",
    "template",
    "userid",
)
log = logging.getLogger(PROG)


def tobool(s):
    try:
        return strtobool(s)
    except ValueError:
        return False


def read_config_from_file_and_env(filename):
    config = {}

    if exists(filename):
        with open(filename) as fp:
            config = json.load(fp)

    for setting in SETTINGS_KEYS:
        val = os.getenv("PLUGIN_" + setting.upper())

        if val is not None:
            config[setting] = val

        if not config.get(setting):
            log.debug(f"Configuration setting '{setting}' not set or empty in config.")

    return config


async def send_notification(config, message):
    token = config.get("accesstoken")
    device_id = config.get("deviceid")
    homeserver = config.get("homeserver", DEFAULT_HOMESERVER)

    client = AsyncClient(homeserver, config["userid"])
    log.debug("Created AsyncClient: %r", client)

    if token and device_id:
        log.debug("Using access token for authentication.")
        client.access_token = token
        client.device_id = device_id
    else:
        log.debug("Trying to log in with password...")
        resp = await client.login(config["password"], device_name=config.get("devicename"))

        # check that we logged in succesfully
        if isinstance(resp, LoginResponse):
            log.debug("Matrix login successful.")
            log.debug("Access token: %s", resp.access_token)
            log.debug("Device ID: %s", resp.device_id)
        else:
            log.error(f"Failed to log in: {resp}")
            await client.close()
            return

    if isinstance(message, dict):
        message.setdefault("msgtype", "m.notice")
        resp = await client.room_send(
            config["roomid"], message_type="m.room.message", content=message
        )
    else:
        resp = await client.room_send(
            config["roomid"],
            message_type="m.room.message",
            content={"msgtype": "m.notice", "body": message},
        )

    log.info(
        "Sent notification message to %s. Response status: %s",
        homeserver,
        resp.transport_response.status,
    )
    await client.close()


def render_message(config):
    pass_environment = config.get("pass_environment", "")

    if not isinstance(pass_environment, list):
        pass_environment = [pass_environment]

    patterns = []
    for value in pass_environment:
        # expand any comma-separetd names/patterns
        if "," in value:
            patterns.extend([p.strip() for p in value.split(",") if p.strip()])
        else:
            patterns.append(value)

    env_names = tuple(os.environ)
    filtered_names = set()

    for pattern in patterns:
        filtered_names.update(fnmatch.filter(env_names, pattern))

    context = {name: os.environ[name] for name in tuple(filtered_names)}
    template = config.get("template", DEFAULT_TEMPLATE)
    return Template(template).safe_substitute(context)


def render_markdown(message, config):
    import bleach
    import markdown

    allowed_attrs = config.get("allowed_attrs", DEFAULT_ALLOWED_ATTRS)
    allowed_tags = config.get("allowed_tags", DEFAULT_ALLOWED_TAGS)
    extensions = config.get("markdown_extensions", DEFAULT_MARKDOWN_EXTENSIONS)

    if isinstance(allowed_attrs, str):
        allowed_attrs = [attr.strip() for attr in allowed_attrs.split(",") if attr.strip()]

    if isinstance(allowed_tags, str):
        allowed_tags = [tag.strip() for tag in allowed_tags.split(",") if tag.strip()]

    if isinstance(extensions, str):
        extensions = [ext.strip() for ext in extensions.split(",") if ext.strip()]

    try:
        md = markdown.Markdown(extensions=extensions)
    except (AttributeError, ImportError, TypeError) as exc:
        log.error("Could not instantiate Markdown formatter: %s", exc)
        return message

    return {
        "formatted_body": bleach.clean(
            md.convert(message), tags=allowed_tags, attributes=allowed_attrs, strip=True
        ),
        "body": message,
        "format": "org.matrix.custom.html",
    }


def main(args=None):
    ap = argparse.ArgumentParser(prog=PROG, description=__doc__.splitlines()[0])
    ap.add_argument(
        "-c",
        "--config",
        metavar="PATH",
        default=CONFIG_FILENAME,
        help="Configuration file path (default: '%(default)s')",
    )
    ap.add_argument(
        "-d",
        "--dry-run",
        action="store_true",
        help="Don't send notification message, only print it.",
    )
    ap.add_argument(
        "-e",
        "--pass-environment",
        nargs="*",
        help=(
            "Comma-separated white-list of environment variable names or name patterns. Only "
            "environment variables matching any of  the given names or patterns will be available "
            "as valid placeholders in the message template. "
            "Accepts shell glob patterns and may be passed more than once (default: 'DRONE_*')."
        ),
    )
    ap.add_argument(
        "-m",
        "--render-markdown",
        action="store_true",
        help="Message is in Markdown format and will be rendered to HTML.",
    )
    ap.add_argument(
        "-v",
        "--verbose",
        action="store_true",
        help="Enable debug level logging.",
    )

    args = ap.parse_args(args)

    logging.basicConfig(
        level="DEBUG" if args.verbose else os.environ.get("PLUGIN_LOG_LEVEL", "INFO").upper(),
        format=os.environ.get("PLUGIN_LOG_FORMAT", "%(levelname)s: %(message)s"),
    )

    try:
        config = read_config_from_file_and_env(args.config)
    except Exception as exc:
        return f"Could not parse configuration: {exc}"

    if args.pass_environment is not None:
        # Security feature: if any environment names/patterns are passed via -e|--pass-environment
        # options, they completely replace any given via the config or environment.
        config["pass_environment"] = args.pass_environment

    if "pass_environment" not in config:
        config["pass_environment"] = DEFAULT_PASS_ENVIRONMENT

    message = render_message(config)

    if tobool(config.get("markdown")) or args.render_markdown:
        log.debug("Rendering markdown message to HTML.")
        try:
            message = render_markdown(message, config)
        except:  ## noqa
            log.exception("Failed to render message with markdown.")

    if not args.dry_run:
        if not config.get("userid"):
            return "userid not found in configuration."

        if not config.get("roomid"):
            return "roomid not found in configuration."

        if not config.get("password") and not config.get("accesstoken"):
            return "No password or accesstoken found in configuration."

        try:
            log.debug("Sending notification to Matrix chat...")
            asyncio.run(send_notification(config, message))
        except KeyboardInterrupt:
            log.info("Interrupted.")
    else:
        print(message)


if __name__ == "__main__":
    sys.exit(main() or 0)