use anyhow::Context;
use lettre::{AsyncSendmailTransport, AsyncSmtpTransport, AsyncTransport, Message, Tokio1Executor};
use std::env;
use url::Url;

pub enum Mailer {
    Smtp(AsyncSmtpTransport<Tokio1Executor>),
    Sendmail(AsyncSendmailTransport<Tokio1Executor>),
}

impl Mailer {
    pub async fn send(&self, msg: Message) -> anyhow::Result<()> {
        match self {
            Mailer::Smtp(m) => {
                m.send(msg).await.context("SMTP send failed")?;
                Ok(())
            }
            Mailer::Sendmail(m) => {
                m.send(msg).await.context("sendmail send failed")?;
                Ok(())
            }
        }
    }
}

pub fn build_mailer_from_env() -> anyhow::Result<Mailer> {
    let raw = env::var("PDS_EMAIL_SMTP_URL")
        .context("PDS_EMAIL_SMTP_URL is not set in your pds.env file")?;

    let url = Url::parse(&raw).context("PDS_EMAIL_SMTP_URL is not a valid URL")?;

    let use_sendmail = url.scheme() == "sendmail"
        || url
            .query_pairs()
            .any(|(k, v)| k == "sendmail" && v == "true");

    if use_sendmail {
        Ok(Mailer::Sendmail(
            AsyncSendmailTransport::<Tokio1Executor>::new(),
        ))
    } else {
        Ok(Mailer::Smtp(
            AsyncSmtpTransport::<Tokio1Executor>::from_url(raw.as_str())?.build(),
        ))
    }
}