use nanorand::{Rng, WyRand};
use sha3::{Digest, Sha3_256};

use crate::{config_manager, error::PeachError, sbot_client};

/// Returns Ok(()) if the supplied password is correct,
/// and returns Err if the supplied password is incorrect.
pub fn verify_password(password: &str) -> Result<(), PeachError> {
    let real_admin_password_hash = config_manager::get_admin_password_hash()?;
    let password_hash = hash_password(&password.to_string());
    if real_admin_password_hash == password_hash {
        Ok(())
    } else {
        Err(PeachError::PasswordIncorrect)
    }
}

/// Checks if the given passwords are valid, and returns Ok() if they are and
/// a PeachError otherwise.
/// Currently this just checks that the passwords are the same,
/// but could be extended to test if they are strong enough.
pub fn validate_new_passwords(new_password1: &str, new_password2: &str) -> Result<(), PeachError> {
    if new_password1 == new_password2 {
        Ok(())
    } else {
        Err(PeachError::PasswordMismatch)
    }
}

/// Sets a new password for the admin user
pub fn set_new_password(new_password: &str) -> Result<(), PeachError> {
    let new_password_hash = hash_password(&new_password.to_string());
    config_manager::set_admin_password_hash(&new_password_hash)?;

    Ok(())
}

/// Creates a hash from a password string
pub fn hash_password(password: &str) -> String {
    let mut hasher = Sha3_256::new();
    // write input message
    hasher.update(password);
    // read hash digest
    let result = hasher.finalize();
    // convert `u8` to `String`
    result[0].to_string()
}

/// Sets a new temporary password for the admin user
/// which can be used to reset the permanent password
pub fn set_new_temporary_password(new_password: &str) -> Result<(), PeachError> {
    let new_password_hash = hash_password(&new_password.to_string());
    config_manager::set_temporary_password_hash(&new_password_hash)?;

    Ok(())
}

/// Returns Ok(()) if the supplied temp_password is correct,
/// and returns Err if the supplied temp_password is incorrect
pub fn verify_temporary_password(password: &str) -> Result<(), PeachError> {
    let temporary_admin_password_hash = config_manager::get_temporary_password_hash()?;
    let password_hash = hash_password(&password.to_string());
    if temporary_admin_password_hash == password_hash {
        Ok(())
    } else {
        Err(PeachError::PasswordIncorrect)
    }
}

/// Generates a temporary password and sends it via ssb dm
/// to the ssb id configured to be the admin of the peachcloud device
pub fn send_password_reset() -> Result<(), PeachError> {
    // initialise random number generator
    let mut rng = WyRand::new();
    // generate a new password of random numbers
    let temporary_password = rng.generate::<u64>().to_string();
    // save this string as a new temporary password
    set_new_temporary_password(&temporary_password)?;
    let domain = config_manager::get_peachcloud_domain()?;

    // then send temporary password as a private ssb message to admin
    let mut msg = format!(
        "Your new temporary password is: {}

If you are on the same WiFi network as your PeachCloud device you can reset your password \
using this link: http://peach.local/reset_password",
        temporary_password
    );
    // if there is an external domain, then include remote link in message
    // otherwise dont include it
    let remote_link = match domain {
        Some(domain) => {
            format!(
                "\n\nOr if you are on a different WiFi network, you can reset your password \
            using the the following link: {}/reset_password",
                domain
            )
        }
        None => "".to_string(),
    };
    msg += &remote_link;
    // finally send the message to the admins
    let peach_config = config_manager::load_peach_config()?;
    for ssb_admin_id in peach_config.ssb_admin_ids {
        sbot_client::private_message(&msg, &ssb_admin_id)?;
    }
    Ok(())
}