"""OpenMeteo API client — live weather data, no API key required."""

import httpx

BASE_URL = "https://api.open-meteo.com/v1/forecast"

# United hub coordinates
HUB_COORDS: dict[str, tuple[float, float]] = {
    "ORD": (41.9742, -87.9073),  # Chicago O'Hare
    "EWR": (40.6895, -74.1745),  # Newark
    "IAH": (29.9902, -95.3368),  # Houston Intercontinental
    "SFO": (37.6213, -122.3790),  # San Francisco
    "DEN": (39.8561, -104.6737),  # Denver
    "LAX": (33.9425, -118.4081),  # Los Angeles
    "IAD": (38.9531, -77.4565),  # Washington Dulles
}

# WMO weather interpretation codes
WMO_CODES: dict[int, str] = {
    0: "Clear sky",
    1: "Mainly clear",
    2: "Partly cloudy",
    3: "Overcast",
    45: "Fog",
    48: "Depositing rime fog",
    51: "Light drizzle",
    53: "Moderate drizzle",
    55: "Dense drizzle",
    61: "Slight rain",
    63: "Moderate rain",
    65: "Heavy rain",
    71: "Slight snow",
    73: "Moderate snow",
    75: "Heavy snow",
    77: "Snow grains",
    80: "Slight rain showers",
    81: "Moderate rain showers",
    82: "Violent rain showers",
    85: "Slight snow showers",
    86: "Heavy snow showers",
    95: "Thunderstorm",
    96: "Thunderstorm with slight hail",
    99: "Thunderstorm with heavy hail",
}

SIGNIFICANT_CODES = {45, 48, 65, 75, 82, 86, 95, 96, 99}


def _interpolate_waypoints(
    origin: tuple[float, float], dest: tuple[float, float], n: int = 2
) -> list[tuple[float, float]]:
    """Generate n intermediate waypoints along a great-circle approximation."""
    points = []
    for i in range(1, n + 1):
        frac = i / (n + 1)
        lat = origin[0] + frac * (dest[0] - origin[0])
        lon = origin[1] + frac * (dest[1] - origin[1])
        points.append((round(lat, 4), round(lon, 4)))
    return points


def _interpret_weather(code: int) -> dict:
    return {
        "code": code,
        "condition": WMO_CODES.get(code, f"Unknown ({code})"),
        "is_significant": code in SIGNIFICANT_CODES,
    }


async def fetch_weather_at_point(
    lat: float, lon: float, client: httpx.AsyncClient
) -> dict:
    """Fetch current weather at a single point."""
    params = {
        "latitude": lat,
        "longitude": lon,
        "current": "temperature_2m,wind_speed_10m,wind_direction_10m,weather_code,visibility,precipitation",
        "timezone": "UTC",
    }
    resp = await client.get(BASE_URL, params=params)
    resp.raise_for_status()
    data = resp.json()
    current = data["current"]
    weather = _interpret_weather(current["weather_code"])
    return {
        "latitude": lat,
        "longitude": lon,
        "temperature_c": current["temperature_2m"],
        "wind_speed_kmh": current["wind_speed_10m"],
        "wind_direction_deg": current["wind_direction_10m"],
        "visibility_m": current.get("visibility"),
        "precipitation_mm": current.get("precipitation", 0),
        "weather": weather,
    }


async def get_weather_along_route(origin: str, destination: str) -> dict:
    """Fetch weather at origin, destination, and en-route waypoints."""
    origin_coords = HUB_COORDS.get(origin.upper())
    dest_coords = HUB_COORDS.get(destination.upper())

    if not origin_coords or not dest_coords:
        return {
            "error": f"Unknown airport code. Known: {', '.join(HUB_COORDS.keys())}",
            "origin": origin,
            "destination": destination,
        }

    waypoints = _interpolate_waypoints(origin_coords, dest_coords)
    all_points = [
        ("origin", origin.upper(), origin_coords),
        *[(f"waypoint_{i+1}", f"WP{i+1}", wp) for i, wp in enumerate(waypoints)],
        ("destination", destination.upper(), dest_coords),
    ]

    results = {}
    significant_events = []

    async with httpx.AsyncClient(timeout=10.0) as client:
        for label, name, (lat, lon) in all_points:
            try:
                weather = await fetch_weather_at_point(lat, lon, client)
                weather["label"] = label
                weather["name"] = name
                results[label] = weather
                if weather["weather"]["is_significant"]:
                    significant_events.append(
                        {
                            "location": name,
                            "condition": weather["weather"]["condition"],
                            "code": weather["weather"]["code"],
                        }
                    )
            except Exception as e:
                results[label] = {"label": label, "name": name, "error": str(e)}

    return {
        "origin": origin.upper(),
        "destination": destination.upper(),
        "waypoints": results,
        "significant_events": significant_events,
        "source": "openmeteo_live",
    }


async def get_weather_forecast_hubs() -> dict:
    """Fetch 4-hour forecast for all United hubs."""
    hubs = ["ORD", "EWR", "IAH", "SFO", "DEN"]
    results = {}

    async with httpx.AsyncClient(timeout=10.0) as client:
        for hub in hubs:
            lat, lon = HUB_COORDS[hub]
            params = {
                "latitude": lat,
                "longitude": lon,
                "hourly": "temperature_2m,wind_speed_10m,weather_code,visibility,precipitation_probability",
                "forecast_hours": 4,
                "timezone": "UTC",
            }
            try:
                resp = await client.get(BASE_URL, params=params)
                resp.raise_for_status()
                data = resp.json()
                hourly = data["hourly"]

                hours = []
                risk_flag = False
                for i in range(len(hourly["time"])):
                    code = hourly["weather_code"][i]
                    weather = _interpret_weather(code)
                    if weather["is_significant"]:
                        risk_flag = True
                    hours.append(
                        {
                            "time": hourly["time"][i],
                            "temperature_c": hourly["temperature_2m"][i],
                            "wind_speed_kmh": hourly["wind_speed_10m"][i],
                            "weather": weather,
                            "visibility_m": hourly.get("visibility", [None])[i]
                            if "visibility" in hourly
                            else None,
                            "precipitation_probability": hourly[
                                "precipitation_probability"
                            ][i],
                        }
                    )

                results[hub] = {
                    "hub": hub,
                    "forecast": hours,
                    "risk_flag": risk_flag,
                }
            except Exception as e:
                results[hub] = {"hub": hub, "error": str(e)}

    return {"hubs": results, "source": "openmeteo_live"}