use std::env;

use uuid::Uuid;
use rand::{thread_rng, Rng};
use rand::distributions::Alphanumeric;
use std::iter;
use postgres::transaction::Transaction;

use failure::Error;
use failure::{err_msg, format_err};

use crossbeam_channel::Receiver;
use lettre::smtp::authentication::{Credentials, Mechanism};
use lettre::smtp::ConnectionReuseParameters;
use lettre::smtp::error::Error as MailError;
use lettre::smtp::extension::ClientId;
use lettre::smtp::response::Response;
use lettre::{SendableEmail, SmtpClient, SmtpTransport, Transport};
use lettre_email::Email as LettreEmail;

use account::Account;
use pg::Db;

#[derive(Debug,Clone,Serialize)]
pub struct Email {
    pub id: Uuid,
    pub email: String,
    pub account: Uuid,
    pub confirmed: bool,
}

#[derive(Debug)]
pub enum Mail {
    Recover { email: String, name: String, token: String },
    Confirm { email: String, name: String, token: String },
}

// create link that will set a token
// put msg saying pls reset your password
// redirect to main page cause cbf

fn recover(email: &String, name: &String, token: &String) -> SendableEmail {
    let body = format!("{:},
the link below will recover your account.
please change your password immediately in the account page.
this link will expire in 48 hours or once used.

http://mnml.gg/api/account/recover?recover_token={:}

glhf
--mnml", name, token);

    LettreEmail::builder()
        .from("machines@mnml.gg")
        .to(email.clone())
        .subject("account recovery")
        .text(body)
        .build()
        .unwrap()
        .into()
}

fn confirm(email: &String, name: &String, token: &String) -> SendableEmail {
    let confirm_body = format!("{:},
please click the link below to confirm your email
http://mnml.gg/api/account/email/confirm?confirm_token={:}

glhf
--mnml", name, token);

    LettreEmail::builder()
        .from("machines@mnml.gg")
        .to(email.clone())
        .subject("email confirmation")
        .text(confirm_body)
        .build()
        .unwrap()
        .into()
}

pub fn send_mail(mailer: &mut SmtpTransport, mail: Mail) -> Result<Response, MailError> {
    let msg = match mail {
        Mail::Recover { email, name, token } => recover(&email, &name, &token),
        Mail::Confirm { email, name, token } => confirm(&email, &name, &token),
    };

    mailer.send(msg)
}

pub fn confirm_email(tx: &mut Transaction, account: &Account, confirm_token: String) -> Result<(String, Uuid), Error> {
    let query = "
        UPDATE emails
        SET confirmed = true, updated_at = now()
        WHERE confirm_token = $1
        AND account = $2
        RETURNING id, email, account
    ";

    let result = tx
        .query(query, &[&confirm_token, &account.id])?;

    let row = result.iter().next()
        .ok_or(format_err!("confirm_token not found {:?}", confirm_token))?;

    let _id: Uuid = row.get(0);
    let email: String = row.get(1);
    let account: Uuid = row.get(2);

    return Ok((email, account));
}

pub fn select(db: &Db, email: &String) -> Result<Email, Error> {
    let query = "
        SELECT id, email, account, confirmed
        FROM emails
        WHERE email = $1;
    ";

    let result = db
        .query(query, &[&email])?;

    let row = result.iter().next()
        .ok_or(err_msg("email found"))?;

    let id: Uuid = row.get(0);
    let email: String = row.get(1);
    let account: Uuid = row.get(2);
    let confirmed: bool = row.get(3);

    return Ok(Email { id, email, account, confirmed });
}

pub fn select_account(db: &Db, account: Uuid) -> Result<Option<Email>, Error> {
    let query = "
        SELECT id, email, account, confirmed
        FROM emails
        WHERE account = $1;
    ";

    let result = db
        .query(query, &[&account])?;

    let row = match result.iter().next() {
        Some(r) => r,
        None => return Ok(None),
    };

    let id: Uuid = row.get(0);
    let email: String = row.get(1);
    let account: Uuid = row.get(2);
    let confirmed: bool = row.get(3);

    return Ok(Some(Email { id, email, account, confirmed }));
}

pub fn set_recovery(tx: &mut Transaction, email: &String) -> Result<String, Error> {
    let mut rng = thread_rng();
    let recover_token: String = iter::repeat(())
        .map(|()| rng.sample(Alphanumeric))
        .take(64)
        .collect();

    let query = "
        UPDATE emails
        SET recover_token = $1, recover_token_expiry = now() + interval '2 days'
        WHERE email = $2
        AND confirmed = true
        RETURNING id, email, account
    ";

    let result = tx
        .query(query, &[&recover_token, &email])?;

    let row = result.iter().next()
        .ok_or(format_err!("no confirmed email found {:?}", email))?;

    let _id: Uuid = row.get(0);
    let _email: String = row.get(1);
    let _account: Uuid = row.get(2);

    return Ok(recover_token);
}

pub fn get_recovery(tx: &mut Transaction, recover_token: &String) -> Result<Email, Error> {
    // set a new token when recovering to prevent multiple access
    let mut rng = thread_rng();
    let new_token: String = iter::repeat(())
        .map(|()| rng.sample(Alphanumeric))
        .take(64)
        .collect();

    let query = "
        UPDATE emails
        SET recover_token = $1, recover_token_expiry = now()
        WHERE recover_token = $2
        AND recover_token_expiry > now()
        AND confirmed = true
        RETURNING id, email, account, confirmed;
    ";

    let result = tx
        .query(query, &[&new_token, &recover_token])?;

    let row = result.iter().next()
        .ok_or(err_msg("no confirmed email found"))?;

    let id: Uuid = row.get(0);
    let email: String = row.get(1);
    let account: Uuid = row.get(2);
    let confirmed: bool = row.get(3);

    return Ok(Email { id, email, account, confirmed });
}

pub fn set(tx: &mut Transaction, account: Uuid, email: &String) -> Result<(Uuid, String), Error> {
    let id = Uuid::new_v4();

    let mut rng = thread_rng();
    let confirm_token: String = iter::repeat(())
        .map(|()| rng.sample(Alphanumeric))
        .take(64)
        .collect();

    let recover_token: String = iter::repeat(())
        .map(|()| rng.sample(Alphanumeric))
        .take(64)
        .collect();

    let insert_query = "
        INSERT INTO emails (id, account, email, confirm_token, confirmed, recover_token)
        VALUES ($1, $2, $3, $4, false, $5)
        RETURNING id;
    ";

    let update_query = "
        UPDATE emails
        SET email = $1, confirm_token = $2, confirmed = false, recover_token = $3
        WHERE account = $4
        RETURNING id;
    ";

    let result = match tx.query(insert_query, &[&id, &account, &email, &confirm_token, &recover_token]) {
        Ok(r) => r,
        // email update probably
        Err(_) => {
            match tx.query(update_query, &[&email, &confirm_token, &recover_token, &account]) {
                Ok(r) => r,
                Err(e) => {
                    warn!("{:?}", e);
                    return Err(err_msg("no email set"));
                },
            }
        }
    };

    match result.iter().next() {
        Some(row) => row,
        None => return Err(err_msg("no email set")),
    };

    return Ok((id, confirm_token));
}

pub fn listen(rx: Receiver<Mail>) -> SmtpTransport {
    let sender = env::var("MAIL_ADDRESS")
        .expect("MAIL_ADDRESS must be set");

    let password = env::var("MAIL_PASSWORD")
        .expect("MAIL_PASSWORD must be set");

    let domain = env::var("MAIL_DOMAIN")
        .expect("MAIL_DOMAIN must be set");

    let mut mailer = SmtpClient::new_simple("smtp.gmail.com").unwrap()
        .hello_name(ClientId::Domain(domain))
        .credentials(Credentials::new(sender, password))
        .smtp_utf8(true)
        .authentication_mechanism(Mechanism::Plain)
        .connection_reuse(ConnectionReuseParameters::ReuseUnlimited)
        .transport();

    info!("mail connected");

    // loop {
    //     match rx.recv() {
    //         Ok(m) => match send_mail(&mut mailer, m) {
    //             Ok(r) => info!("{:?}", r),
    //             Err(e) => warn!("{:?}", e),
    //         },
    //         Err(e) => {
    //             error!("{:?}", e);
    //             panic!("mail thread cannot continue");
    //         },
    //     };
    // }

    // Explicitly close the SMTP transaction as we enabled connection reuse
    // mailer.close();
    return mailer;
}