import os
import sys
import traceback
import smtplib
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

import db

BASE_URL = os.environ["BASE_URL"]

def send_email(subject: str, body: str, recipient: str):
  pass

email_env_vars = [
  "EMAIL_HOST",
  "EMAIL_PORT",
  "EMAIL_HOST_USER",
  "EMAIL_HOST_PASSWORD",
  "EMAIL_USE_TLS",
  "EMAIL_MESSAGE_FROM",
]

email_enabled = any(var in os.environ for var in email_env_vars)
if email_enabled:
  for var in email_env_vars:
    if var not in os.environ:
      raise Exception(f"Some EMAIL_ variables are set but {var} is not set")

  email_host = os.environ["EMAIL_HOST"]
  email_port = int(os.environ["EMAIL_PORT"])
  email_host_user = os.environ["EMAIL_HOST_USER"]
  email_host_password = os.environ["EMAIL_HOST_PASSWORD"]
  email_use_tls = os.environ["EMAIL_USE_TLS"].lower() in ["true", "1", "yes"]
  email_message_from = os.environ["EMAIL_MESSAGE_FROM"]
  email_headers_raw = os.environ.get("EMAIL_HEADERS", "")
  email_headers: dict[str, str] = {}
  for header in email_headers_raw.split(","):
    if not header:
      continue
    key, value = header.split("=", 1)
    email_headers[key] = value

  print(f"SMTP email client enabled using email host {email_host}")

  def _actual_send_email(subject: str, body: str, recipient: str):
    if not email_enabled:
      return

    msg = MIMEMultipart()
    msg['From'] = email_message_from
    msg['To'] = recipient
    msg['Subject'] = subject
    msg.attach(MIMEText(body, 'plain'))
    msg.add_header("Content-Type", "text/plain; charset=utf-8")
    for key, value in email_headers.items():
      msg.add_header(key, value)

    with smtplib.SMTP(email_host, email_port) as server:
      if email_use_tls:
        server.starttls()

      server.login(email_host_user, email_host_password)
      server.send_message(msg)

  send_email = _actual_send_email
else:
  print("SMTP email client not enabled")

def send_participation_email(poll_id: str, voter_name: str):
  poll = db.get_poll(poll_id)
  if not poll or poll.author_email is None or poll.author_email.strip() == "":
    return

  print(f"Sending participation email to {poll.author_email}")
  try:
    send_email(
      subject=f"{voter_name} participated in your poll \"{poll.title}\"",
      body=f"{voter_name} participated in your diddle \"{poll.title}\".\n\n"
            f"View the results at {BASE_URL}/poll/{poll.id}\n"
            f"Manage your diddle at {BASE_URL}/manage/{poll.manage_code}\n"
            "You will be notified by email when someone participates.",
      recipient=poll.author_email,
    )
  except Exception as e:
    traceback.print_exc(file=sys.stderr)
    print(f"Failed to send participation email to {poll.author_email}", file=sys.stderr)

def send_poll_created_email(poll_id: str):
  poll = db.get_poll(poll_id)
  if not poll or poll.author_email is None or poll.author_email.strip() == "":
    return

  print(f"Sending poll created email to {poll.author_email}")
  try:
    send_email(
      subject=f"You created a new diddle \"{poll.title}\"",
      body=f"Manage your diddle at {BASE_URL}/manage/{poll.manage_code}\n"
            "You will be notified by email when someone participates.",
      recipient=poll.author_email,
    )
  except Exception as e:
    traceback.print_exc(file=sys.stderr)
    print(f"Failed to send poll created email to {poll.author_email}", file=sys.stderr)