#!/usr/bin/env python3

"""Get current weather condition and forecast for Polybar."""

import requests
import logging
import argparse
import sys
import os
import subprocess
import time
from systemd import journal

logger = logging.getLogger("weather")


def get_location():
    """Return current location as latitude/longitude tuple."""
    logger.debug("query MaxMind for location")
    r = requests.get(
        "https://geoip.maxmind.com/geoip/v2.1/city/me",
        headers={"referer": "https://www.maxmind.com/en/locate-my-ip-address"},
        timeout=10,
    )
    r.raise_for_status()
    data = r.json()
    logger.debug("current location data: %s", data)
    location = (data.get("city") or data["country"])["names"]["en"]
    logger.info(f"current location: {location}")
    return ((data["location"]["latitude"], data["location"]["longitude"]), location)


def get_weather(latitude, longitude):
    """Return data from met.no."""
    logger.debug("query met.no for %s, %s", latitude, longitude)
    r = requests.get(
        "https://api.met.no/weatherapi/locationforecast/2.0/complete.json",
        params={
            "lat": f"{latitude:.4f}",
            "lon": f"{longitude:.4f}",
        },
        headers={
            "user-agent": "WeatherWidget https://github.com/vincentbernat/i3wm-configuration"
        },
        timeout=10,
    )
    r.raise_for_status()
    data = r.json()
    logger.debug("weather data: %s", data)
    return data


def format_icon(symbol_code):
    """Translate met.no icon to Font Awesome."""
    # See https://github.com/metno/weathericons/blob/main/weather/legend.csv
    symbol_code = symbol_code.removeprefix("light")
    symbol_code = symbol_code.removeprefix("heavy")
    if symbol_code.startswith("ss"):
        symbol_code = symbol_code[1:]
    icon = {
        "clearsky_day": "\uf00d",
        "clearsky_night": "\uf02e",
        "cloudy": "\uf013",
        "fair_day": "\uf002",
        "fair_night": "\uf086",
        "fog": "\uf014",
        "partlycloudy_day": "\uf002",
        "partlycloudy_night": "\uf086",
        "rain": "\uf019",
        "rainandthunder": "\uf01e",
        "rainshowers_day": "\uf009",
        "rainshowers_night": "\uf037",
        "rainshowersandthunder_day": "\uf010",
        "rainshowersandthunder_night": "\uf03b",
        "sleet": "\uf0b5",
        "sleetandthunder": "\uf01d",
        "sleetshowers_day": "\uf0b2",
        "sleetshowers_night": "\uf0b3",
        "sleetshowersandthunder_day": "\uf068",
        "sleetshowersandthunder_night": "\uf069",
        "snow": "\uf01b",
        "snowandthunder": "\uf06b",
        "snowshowers_day": "\uf009",
        "snowshowers_night": "\uf038",
        "snowshowersandthunder_day": "\uf06b",
        "snowshowersandthunder_night": "\uf06c",
    }.get(symbol_code, "?")
    logger.debug("symbol %s translated to %s (\\u%04x)", symbol_code, icon, ord(icon))
    output = ["%{Tx}", icon, "%{T-}"]
    return "".join(output)


def update_status(status, output):
    """Update current status."""
    # Write it to file
    with open(output, "w") as f:
        f.write(status)

    # Send it to polybar
    subprocess.run(["polybar-msg", "action", f"#weather.send.{status}"])


if __name__ == "__main__":
    # Parse
    description = sys.modules[__name__].__doc__
    parser = argparse.ArgumentParser(description=description)
    parser.add_argument(
        "--debug",
        "-d",
        action="store_true",
        default=False,
        help="enable debugging",
    )
    parser.add_argument(
        "--font-index", default=4, type=int, help="Polybar font 1-index"
    )
    parser.add_argument(
        "--output",
        default=f"{os.environ['XDG_RUNTIME_DIR']}/i3/weather.txt",
        help="Output destination",
    )
    parser.add_argument(
        "--online-timeout",
        default=30,
        type=int,
        help="Wait up to TIMEOUT minutes to be online",
    )
    options = parser.parse_args()

    # Logging
    root = logging.getLogger("")
    root.setLevel(logging.WARNING)
    logger.setLevel(options.debug and logging.DEBUG or logging.INFO)
    if sys.stderr.isatty():
        ch = logging.StreamHandler()
        ch.setFormatter(logging.Formatter("%(levelname)s: %(message)s"))
        root.addHandler(ch)
    else:
        root.addHandler(journal.JournalHandler(SYSLOG_IDENTIFIER=logger.name))

    try:
        # Get location
        while True:
            try:
                location, city = get_location()
                break
            except (requests.exceptions.ConnectionError, requests.exceptions.Timeout):
                # Wait to be online
                logger.info("not online, waiting")
                update_status("", options.output)
                time.sleep(5)
                process = subprocess.run(
                    ["nm-online", "-q", "-t", str(options.online_timeout * 60)]
                )
                if process.returncode != 0:
                    logger.warning("not online, exiting")
                    sys.exit(1)

        # Grab current weather and daily forecast
        weather = get_weather(*location)
        weather = weather["properties"]["timeseries"]

        # Compute min/max temperatures for the forecast. We use the next 24
        # hours. So we use 18 entries.
        mintemp = min(
            d["data"]["next_6_hours"]["details"]["air_temperature_min"]
            for d in weather[:18]
        )
        maxtemp = max(
            d["data"]["next_6_hours"]["details"]["air_temperature_max"]
            for d in weather[:18]
        )

        # Format output
        conditions = [
            # Current conditions: use the symbol for the next hour and the
            # instant temperature
            format_icon(weather[0]["data"]["next_1_hours"]["summary"]["symbol_code"]),
            "{}°C".format(
                round(weather[0]["data"]["instant"]["details"]["air_temperature"])
            ),
            # Forecast: use the symbol for the next 6 hours and the period after
            format_icon(weather[0]["data"]["next_6_hours"]["summary"]["symbol_code"])
            + format_icon(weather[6]["data"]["next_6_hours"]["summary"]["symbol_code"]),
            # And the temperature range computed for the next 24 hours
            "{}—{}°C".format(round(mintemp), round(maxtemp)),
        ]
        city = city.replace("%", "%%")
        conditions.insert(0, f"%{{F#bbb}}{city}%{{F-}}")
        output = " ".join(conditions).replace("%{Tx}", "%%{T%d}" % options.font_index)
        logger.debug("output: %s", output)

        update_status(output, options.output)

    except Exception as e:
        logger.exception("%s", e)
        sys.exit(1)
    sys.exit(0)