#!/usr/bin/env python3
"""Erstellt einen kombinierten Wetterbericht für den letzten Kalendermonat."""

import os
import smtplib
import tempfile
from collections import defaultdict
from datetime import datetime, timedelta, timezone
from email.mime.image import MIMEImage
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

import matplotlib.dates as mdates
import matplotlib.patches as mpatches
import matplotlib.pyplot as plt
import requests
from dotenv import load_dotenv

load_dotenv()

VERSION = os.getenv("APP_VERSION", "?")

API_BASE_URL = os.getenv("API_BASE_URL", "https://stwwetter.fuerst-stuttgart.de/api")
MAIL_SERVER = os.getenv("MAIL_SERVER")
MAIL_PORT = int(os.getenv("MAIL_PORT", "587"))
MAIL_USER = os.getenv("MAIL_USER")
MAIL_PASSWORD = os.getenv("MAIL_PASSWORD")
MAIL_FROM = os.getenv("MAIL_FROM")
MAIL_TO = [a.strip() for a in os.getenv("MAIL_TO", "").split(",") if a.strip()]
MAIL_SUBJECT = os.getenv("MAIL_SUBJECT", "Wetterbericht letzter Monat")

MONTHS_DE = [
    "Januar", "Februar", "März", "April", "Mai", "Juni",
    "Juli", "August", "September", "Oktober", "November", "Dezember",
]

plt.rcParams.update({
    "figure.facecolor": "#f8f9fa",
    "axes.facecolor": "#ffffff",
    "axes.grid": True,
    "grid.alpha": 0.4,
    "axes.spines.top": False,
    "axes.spines.right": False,
    "font.size": 11,
})


def last_month_range() -> tuple[datetime, datetime, str]:
    today = datetime.now(timezone.utc)
    first_of_this = today.replace(day=1, hour=0, minute=0, second=0, microsecond=0)
    start = (first_of_this - timedelta(days=1)).replace(day=1, hour=0, minute=0, second=0, microsecond=0)
    end = first_of_this  # exklusives Ende: < Juni 1 = komplett Mai
    label = f"{MONTHS_DE[start.month - 1]} {start.year}"
    return start, end, label


def fetch(path: str, params: dict) -> list:
    url = f"{API_BASE_URL}{path}"
    resp = requests.get(url, params=params, timeout=30)
    resp.raise_for_status()
    return resp.json()


def parse_dt(s: str) -> datetime:
    return datetime.fromisoformat(s.replace("Z", "+00:00"))


def _data_temp_minmax(start: datetime, end: datetime):
    data = fetch("/weather/daily-aggregated-range", {
        "start": start.isoformat(), "end": end.isoformat(),
    })
    dates = [parse_dt(d["datetime"]) for d in data]
    t_min = [d["min_temperature"] for d in data]
    t_max = [d["max_temperature"] for d in data]
    return dates, t_min, t_max


def _data_temp_hourly(start: datetime, end: datetime):
    data = fetch("/weather/hourly-aggregated-range", {
        "start": start.isoformat(), "end": end.isoformat(),
    })
    dates = [parse_dt(d["datetime"]) for d in data]
    temps = [d["temperature"] for d in data]
    return dates, temps


def _data_rain_daily(start: datetime, end: datetime):
    data = fetch("/weather/range", {
        "start": start.isoformat(), "end": end.isoformat(), "limit": 50000,
    })
    by_day: dict[str, list[float]] = defaultdict(list)
    for d in data:
        if d.get("rain") is not None:
            by_day[parse_dt(d["datetime"]).strftime("%Y-%m-%d")].append(d["rain"])

    dates, rain = [], []
    for day_key in sorted(by_day):
        vals = by_day[day_key]
        daily = max(vals) - min(vals)
        if daily < 0:
            daily = max(vals)
        dates.append(datetime.fromisoformat(day_key).replace(tzinfo=timezone.utc))
        rain.append(round(daily, 1))
    return dates, rain


def create_combined_chart(start: datetime, end: datetime, label: str) -> bytes:
    dates_mm, t_min, t_max = _data_temp_minmax(start, end)
    dates_h, temps = _data_temp_hourly(start, end)
    dates_r, rain = _data_rain_daily(start, end)

    fig, axes = plt.subplots(3, 1, figsize=(13, 16))
    fig.suptitle(f"Wetterbericht – {label}", fontsize=15, fontweight="bold", y=0.985)

    # --- Chart 1: Tages-Min / Tages-Max ---
    ax = axes[0]
    ax.plot(dates_mm, t_max, color="#e05c2a", linewidth=2, marker="o",
            markersize=4, label="Tages-Maximum")
    ax.plot(dates_mm, t_min, color="#2a7be0", linewidth=2, marker="o",
            markersize=4, label="Tages-Minimum")
    ax.fill_between(dates_mm, t_min, t_max, alpha=0.12, color="#888888")
    ax.set_title("Temperaturverlauf (Tages-Min / Tages-Max)", fontweight="bold", pad=10)
    ax.set_ylabel("Temperatur (°C)")
    ax.set_xlim(start - timedelta(hours=12), end + timedelta(hours=12))
    ax.xaxis.set_major_formatter(mdates.DateFormatter("%d.%m."))
    ax.xaxis.set_major_locator(mdates.DayLocator(interval=3))
    plt.setp(ax.get_xticklabels(), rotation=0, ha="center")
    ax.legend(framealpha=0.8)

    # --- Chart 2: Stundenmittel ---
    ax = axes[1]
    ax.plot(dates_h, temps, color="#2a7be0", linewidth=1.5, label="Stundenmittel")
    ax.set_title("Temperaturverlauf (Stundenmittel)", fontweight="bold", pad=10)
    ax.set_ylabel("Temperatur (°C)")
    ax.set_xlim(start - timedelta(hours=12), end + timedelta(hours=12))
    ax.xaxis.set_major_formatter(mdates.DateFormatter("%d.%m."))
    ax.xaxis.set_major_locator(mdates.DayLocator(interval=3))
    plt.setp(ax.get_xticklabels(), rotation=0, ha="center")
    ax.legend(framealpha=0.8)

    # --- Chart 3: Niederschlag ---
    ax = axes[2]
    colors = ["#2a7be0" if r > 0 else "#ccddee" for r in rain]
    ax.bar(dates_r, rain, color=colors, width=0.7, label="Niederschlag")
    total = sum(rain)
    ax.set_title(f"Niederschlag pro Tag  (Summe: {total:.1f} mm)",
                 fontweight="bold", pad=10)
    ax.set_ylabel("Niederschlag (mm)")
    ax.set_xlim(start - timedelta(hours=12), end + timedelta(hours=12))
    ax.xaxis.set_major_formatter(mdates.DateFormatter("%d.%m."))
    ax.xaxis.set_major_locator(mdates.DayLocator(interval=3))
    plt.setp(ax.get_xticklabels(), rotation=0, ha="center")
    ax.legend(framealpha=0.8)

    fig.tight_layout(rect=[0.015, 0.055, 0.985, 0.975])

    # Rahmen um die gesamte Figure
    border = mpatches.FancyBboxPatch(
        (0.008, 0.008), 0.984, 0.984,
        boxstyle="square,pad=0",
        linewidth=2, edgecolor="#999999", facecolor="none",
        transform=fig.transFigure, clip_on=False,
    )
    fig.add_artist(border)

    # Footer: links E-Mail, Mitte Watermark, rechts Version + Datum
    footer_y = 0.030
    footer_kw = dict(va="center", fontsize=9, color="#999999",
                     transform=fig.transFigure)
    build_date = datetime.now(timezone.utc).strftime("%d.%m.%Y")
    fig.text(0.022, footer_y, "mailto:rexfue@gmail.com",
             ha="left", **footer_kw)
    fig.text(0.5, footer_y, "Wetterstation der Sternwarte Welzheim",
             ha="center", **footer_kw)
    fig.text(0.978, footer_y, f"V {VERSION}  ·  {build_date}",
             ha="right", **footer_kw)

    with tempfile.NamedTemporaryFile(suffix=".png", delete=False) as f:
        fig.savefig(f.name, dpi=150, bbox_inches="tight")
        path = f.name
    plt.close(fig)
    with open(path, "rb") as f:
        data = f.read()
    os.unlink(path)
    return data


def send_email(png: bytes, label: str) -> None:
    if not all([MAIL_SERVER, MAIL_USER, MAIL_PASSWORD, MAIL_FROM, MAIL_TO]):
        print("E-Mail-Konfiguration unvollständig – Mail wird nicht gesendet.")
        return

    # multipart/related: HTML + CID-Bild werden als Einheit behandelt
    related = MIMEMultipart("related")

    msg = MIMEMultipart("mixed")
    msg["Subject"] = f"{MAIL_SUBJECT} – {label}"
    msg["From"] = MAIL_FROM
    msg["To"] = ", ".join(MAIL_TO)
    msg.attach(related)

    body = MIMEText(
        f"<html><body>"
        f"<h2>Wetterbericht – {label}</h2>"
        f'<img src="cid:chart@weather" style="max-width:100%;"/>'
        f"</body></html>",
        "html",
    )
    related.attach(body)

    img = MIMEImage(png, name="wetterbericht.png")
    img.add_header("Content-ID", "<chart@weather>")
    img.add_header("Content-Disposition", "inline", filename="wetterbericht.png")
    related.attach(img)

    with smtplib.SMTP(MAIL_SERVER, MAIL_PORT) as smtp:
        smtp.ehlo()
        smtp.starttls()
        smtp.login(MAIL_USER, MAIL_PASSWORD)
        smtp.send_message(msg)

    print(f"Mail gesendet an: {', '.join(MAIL_TO)}")


def main() -> None:
    start, end, label = last_month_range()
    print(f"Hole Wetterdaten für {label} ({start.date()} – {end.date()}) …")

    png = create_combined_chart(start, end, label)

    os.makedirs("images", exist_ok=True)
    path = os.path.join("images", "wetterbericht.png")
    with open(path, "wb") as f:
        f.write(png)
    print(f"Diagramm erstellt → {path}")

    send_email(png, label)


if __name__ == "__main__":
    main()