import io
import smtplib
import ssl
from email.message import EmailMessage
from itsdangerous import URLSafeTimedSerializer
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
from config import Config

from pathlib import Path
from weasyprint import HTML


def generate_pdf_from_html(html_string, output_path, base_url=None):
    output_path = Path(output_path)
    output_path.parent.mkdir(parents=True, exist_ok=True)
    HTML(string=html_string, base_url=base_url).write_pdf(str(output_path))
    return output_path


serializer = URLSafeTimedSerializer(Config.SECRET_KEY)


def generate_activation_token(email):
    return serializer.dumps(email, salt='account-activation')



def verify_activation_token(token, max_age=86400):
    return serializer.loads(token, salt='account-activation', max_age=max_age)



def send_mail(to_address, subject, body):
    msg = EmailMessage()
    msg['Subject'] = subject
    msg['From'] = Config.MAIL_SENDER
    msg['To'] = to_address
    msg.set_content(body)

    # SMTPS
    if Config.SMTP_PORT == 465:
        context = ssl.create_default_context()
        with smtplib.SMTP_SSL(Config.SMTP_SERVER, Config.SMTP_PORT, context=context) as server:
            if Config.SMTP_USERNAME:
                server.login(Config.SMTP_USERNAME, Config.SMTP_PASSWORD)
            server.send_message(msg)
        return

    # Normales SMTP, z. B. Port 25
    with smtplib.SMTP(Config.SMTP_SERVER, Config.SMTP_PORT) as server:
        server.ehlo()

        if Config.MAIL_USE_TLS:
            server.starttls(context=ssl.create_default_context())
            server.ehlo()

        if Config.SMTP_USERNAME and Config.SMTP_USERNAME.strip():
            server.login(Config.SMTP_USERNAME, Config.SMTP_PASSWORD)

        server.send_message(msg)



def create_assessment_chart(labels, yes_counts, output_path):
    fig, ax = plt.subplots(figsize=(11, 5))
    x_values = list(range(len(labels)))

    ax.plot(x_values, yes_counts, marker='o')

    for x, y in zip(x_values, yes_counts):
        if y >= 7:
            color = 'green'
        elif y >= 4:
            color = 'orange'
        else:
            color = 'red'
        ax.scatter([x], [y], color=color, s=120)

    ax.set_xticks(x_values)
    ax.set_xticklabels(labels, rotation=20, ha='right')
    ax.set_ylim(0, 8)
    ax.set_ylabel('Anzahl JA-Antworten')
    ax.set_xlabel('Themen')
    ax.set_title('Assessment-Ergebnis')
    ax.grid(True, axis='y', alpha=0.3)
    fig.tight_layout()
    fig.savefig(output_path, dpi=150)
    plt.close(fig)



def create_chart_bytes(labels, yes_counts):
    buffer = io.BytesIO()
    fig, ax = plt.subplots(figsize=(11, 5))
    x_values = list(range(len(labels)))
    ax.plot(x_values, yes_counts, marker='o')
    for x, y in zip(x_values, yes_counts):
        if y >= 7:
            color = 'green'
        elif y >= 4:
            color = 'orange'
        else:
            color = 'red'
        ax.scatter([x], [y], color=color, s=120)
    ax.set_xticks(x_values)
    ax.set_xticklabels(labels, rotation=20, ha='right')
    ax.set_ylim(0, 8)
    ax.set_ylabel('Anzahl JA-Antworten')
    ax.set_xlabel('Themen')
    ax.set_title('Assessment-Ergebnis')
    ax.grid(True, axis='y', alpha=0.3)
    fig.tight_layout()
    fig.savefig(buffer, format='png', dpi=150)
    plt.close(fig)
    buffer.seek(0)
    return buffer