use lettre::smtp::authentication::Credentials;
use lettre::smtp::ConnectionReuseParameters;
use lettre::{ClientSecurity, ClientTlsParameters, SmtpClient, SmtpTransport, Transport};
use lettre_email::EmailBuilder;
use native_tls::{Protocol, TlsConnector};

use crate::api::EmptyResult;
use crate::auth::{encode_jwt, generate_invite_claims};
use crate::config::MailConfig;
use crate::error::Error;
use crate::CONFIG;

fn mailer(config: &MailConfig) -> SmtpTransport {
    let client_security = if config.smtp_ssl {
        let tls = TlsConnector::builder()
            .min_protocol_version(Some(Protocol::Tlsv11))
            .build()
            .unwrap();

        ClientSecurity::Required(ClientTlsParameters::new(config.smtp_host.clone(), tls))
    } else {
        ClientSecurity::None
    };

    let smtp_client = SmtpClient::new((config.smtp_host.as_str(), config.smtp_port), client_security).unwrap();

    let smtp_client = match (&config.smtp_username, &config.smtp_password) {
        (Some(user), Some(pass)) => smtp_client.credentials(Credentials::new(user.clone(), pass.clone())),
        _ => smtp_client,
    };

    smtp_client
        .smtp_utf8(true)
        .connection_reuse(ConnectionReuseParameters::NoReuse)
        .transport()
}

fn get_text(template_name: &'static str, data: serde_json::Value) -> Result<(String, String), Error> {
    let text = CONFIG.render_template(template_name, &data)?;
    let mut text_split = text.split("<!---------------->");

    let subject = match text_split.next() {
        Some(s) => s.trim().to_string(),
        None => err!("Template doesn't contain subject"),
    };

    let body = match text_split.next() {
        Some(s) => s.trim().to_string(),
        None => err!("Template doesn't contain body"),
    };

    Ok((subject, body))
}

pub fn send_password_hint(address: &str, hint: Option<String>, config: &MailConfig) -> EmptyResult {
    let template_name = if hint.is_some() {
        "email/pw_hint_some"
    } else {
        "email/pw_hint_none"
    };

    let (subject, body) = get_text(template_name, json!({ "hint": hint }))?;

    send_email(&address, &subject, &body, &config)
}

pub fn send_invite(
    address: &str,
    uuid: &str,
    org_id: Option<String>,
    org_user_id: Option<String>,
    org_name: &str,
    invited_by_email: Option<String>,
    config: &MailConfig,
) -> EmptyResult {
    let claims = generate_invite_claims(
        uuid.to_string(),
        String::from(address),
        org_id.clone(),
        org_user_id.clone(),
        invited_by_email.clone(),
    );
    let invite_token = encode_jwt(&claims);

    let (subject, body) = get_text(
        "email/send_org_invite",
        json!({
            "url": CONFIG.domain(),
            "org_id": org_id.unwrap_or("_".to_string()),
            "org_user_id": org_user_id.unwrap_or("_".to_string()),
            "email": address,
            "org_name": org_name,
            "token": invite_token,
        }),
    )?;

    send_email(&address, &subject, &body, &config)
}

pub fn send_invite_accepted(new_user_email: &str, address: &str, org_name: &str, config: &MailConfig) -> EmptyResult {
    let (subject, body) = get_text(
        "email/invite_accepted",
        json!({
            "url": CONFIG.domain(),
            "email": new_user_email,
            "org_name": org_name,
        }),
    )?;

    send_email(&address, &subject, &body, &config)
}

pub fn send_invite_confirmed(address: &str, org_name: &str, config: &MailConfig) -> EmptyResult {
    let (subject, body) = get_text(
        "email/invite_confirmed",
        json!({
            "url": CONFIG.domain(),
            "org_name": org_name,
        }),
    )?;

    send_email(&address, &subject, &body, &config)
}

fn send_email(address: &str, subject: &str, body: &str, config: &MailConfig) -> EmptyResult {
    let email = EmailBuilder::new()
        .to(address)
        .from((config.smtp_from.clone(), config.smtp_from_name.clone()))
        .subject(subject)
        .header(("Content-Type", "text/html"))
        .body(body)
        .build()
        .map_err(|e| Error::new("Error building email", e.to_string()))?;

    mailer(config)
        .send(email.into())
        .map_err(|e| Error::new("Error sending email", e.to_string()))
        .and(Ok(()))
}