use log::info;
use rocket::form::{Form, FromForm};
use rocket::http::{Cookie, CookieJar, Status};
use rocket::request::{self, FlashMessage, FromRequest, Request};
use rocket::response::{Flash, Redirect};
use rocket::serde::{
    json::{Json, Value},
    Deserialize, Serialize,
};
use rocket::{get, post, Config};
use rocket_dyn_templates::Template;

use peach_lib::error::PeachError;
use peach_lib::password_utils;

use crate::error::PeachWebError;
use crate::utils::{build_json_response, TemplateOrRedirect};

// HELPERS AND STRUCTS FOR AUTHENTICATION WITH COOKIES

pub const AUTH_COOKIE_KEY: &str = "peachweb_auth";
pub const ADMIN_USERNAME: &str = "admin";

/// Note: Currently we use an empty struct for the Authenticated request guard
/// because there is only one user to be authenticated, and no data needs to be stored here.
/// In a multi-user authentication scheme, we would store the user_id in this struct,
/// and retrieve the correct user via the user_id stored in the cookie.
pub struct Authenticated;

#[derive(Debug)]
pub enum LoginError {
    UserNotLoggedIn,
}

/// Request guard which returns an empty Authenticated struct from the request
/// if and only if the user has a cookie which proves they are authenticated with peach-web.
///
/// Note that cookies.get_private uses encryption, which means that this private cookie
/// cannot be inspected, tampered with, or manufactured by clients.
#[rocket::async_trait]
impl<'r> FromRequest<'r> for Authenticated {
    type Error = LoginError;

    async fn from_request(req: &'r Request<'_>) -> request::Outcome<Self, Self::Error> {
        // check for `disable_auth` config value; set to `false` if unset
        // can be set via the `ROCKET_DISABLE_AUTH` environment variable
        //  - env var, if set, takes precedence over value defined in `Rocket.toml`
        let authentication_is_disabled: bool = match Config::figment().find_value("disable_auth") {
            // deserialize the boolean value; set to `false` if an error is encountered
            Ok(value) => value.deserialize().unwrap_or(false),
            Err(_) => false,
        };
        if authentication_is_disabled {
            let auth = Authenticated {};
            request::Outcome::Success(auth)
        } else {
            let authenticated = req
                .cookies()
                .get_private(AUTH_COOKIE_KEY)
                .and_then(|cookie| cookie.value().parse().ok())
                .map(|_value: String| Authenticated {});
            match authenticated {
                Some(auth) => request::Outcome::Success(auth),
                None => request::Outcome::Failure((Status::Forbidden, LoginError::UserNotLoggedIn)),
            }
        }
    }
}

// HELPERS AND ROUTES FOR /login

#[derive(Debug, Serialize)]
pub struct LoginContext {
    pub back: Option<String>,
    pub flash_name: Option<String>,
    pub flash_msg: Option<String>,
    pub title: Option<String>,
}

impl LoginContext {
    pub fn build() -> LoginContext {
        LoginContext {
            back: None,
            flash_name: None,
            flash_msg: None,
            title: None,
        }
    }
}

#[get("/login")]
pub fn login(flash: Option<FlashMessage>) -> Template {
    let mut context = LoginContext::build();
    context.back = Some("/".to_string());
    context.title = Some("Login".to_string());
    // check to see if there is a flash message to display
    if let Some(flash) = flash {
        // add flash message contents to the context object
        context.flash_name = Some(flash.kind().to_string());
        context.flash_msg = Some(flash.message().to_string());
    };
    Template::render("login", &context)
}

#[derive(Debug, Deserialize, FromForm)]
pub struct LoginForm {
    pub username: String,
    pub password: String,
}

/// Takes in a LoginForm and returns Ok(()) if username and password
/// are correct to authenticate with peach-web.
///
/// Note: currently there is only one user, and the username should always
/// be "admin".
pub fn verify_login_form(login_form: LoginForm) -> Result<(), PeachError> {
    password_utils::verify_password(&login_form.password)
}

#[post("/login", data = "<login_form>")]
pub fn login_post(login_form: Form<LoginForm>, cookies: &CookieJar<'_>) -> TemplateOrRedirect {
    let result = verify_login_form(login_form.into_inner());
    match result {
        Ok(_) => {
            // if successful login, add a cookie indicating the user is authenticated
            // and redirect to home page
            // NOTE: since we currently have just one user, the value of the cookie
            // is just admin (this is arbitrary).
            // If we had multiple users, we could put the user_id here.
            cookies.add_private(Cookie::new(AUTH_COOKIE_KEY, ADMIN_USERNAME));
            TemplateOrRedirect::Redirect(Redirect::to("/"))
        }
        Err(_) => {
            // if unsuccessful login, render /login page again
            let mut context = LoginContext::build();
            context.back = Some("/".to_string());
            context.title = Some("Login".to_string());
            context.flash_name = Some("error".to_string());
            let flash_msg = "Invalid password".to_string();
            context.flash_msg = Some(flash_msg);
            TemplateOrRedirect::Template(Template::render("login", &context))
        }
    }
}

// HELPERS AND ROUTES FOR /logout

#[get("/logout")]
pub fn logout(cookies: &CookieJar<'_>) -> Flash<Redirect> {
    // logout authenticated user
    info!("Attempting deauthentication of user.");
    cookies.remove_private(Cookie::named(AUTH_COOKIE_KEY));
    Flash::success(Redirect::to("/login"), "Logged out")
}

// HELPERS AND ROUTES FOR /reset_password

#[derive(Debug, Deserialize, FromForm)]
pub struct ResetPasswordForm {
    pub temporary_password: String,
    pub new_password1: String,
    pub new_password2: String,
}

#[derive(Debug, Serialize)]
pub struct ResetPasswordContext {
    pub back: Option<String>,
    pub title: Option<String>,
    pub flash_name: Option<String>,
    pub flash_msg: Option<String>,
}

impl ResetPasswordContext {
    pub fn build() -> ResetPasswordContext {
        ResetPasswordContext {
            back: None,
            title: None,
            flash_name: None,
            flash_msg: None,
        }
    }
}

#[derive(Debug, Serialize)]
pub struct ChangePasswordContext {
    pub back: Option<String>,
    pub title: Option<String>,
    pub flash_name: Option<String>,
    pub flash_msg: Option<String>,
}

impl ChangePasswordContext {
    pub fn build() -> ChangePasswordContext {
        ChangePasswordContext {
            back: None,
            title: None,
            flash_name: None,
            flash_msg: None,
        }
    }
}

/// Verify, validate and save the submitted password. This function is publicly exposed for users who have forgotten their password.
pub fn save_reset_password_form(password_form: ResetPasswordForm) -> Result<(), PeachWebError> {
    info!(
        "reset password!: {} {} {}",
        password_form.temporary_password, password_form.new_password1, password_form.new_password2
    );
    password_utils::verify_temporary_password(&password_form.temporary_password)?;
    // if the previous line did not throw an error, then the secret_link is correct
    password_utils::validate_new_passwords(
        &password_form.new_password1,
        &password_form.new_password2,
    )?;
    // if the previous line did not throw an error, then the new password is valid
    password_utils::set_new_password(&password_form.new_password1)?;
    Ok(())
}

/// Password reset request handler. This route is used by a user who is not logged in
/// and is specifically for users who have forgotten their password.
#[get("/reset_password")]
pub fn reset_password(flash: Option<FlashMessage>) -> Template {
    let mut context = ResetPasswordContext::build();
    context.back = Some("/".to_string());
    context.title = Some("Reset Password".to_string());
    // check to see if there is a flash message to display
    if let Some(flash) = flash {
        // add flash message contents to the context object
        context.flash_name = Some(flash.kind().to_string());
        context.flash_msg = Some(flash.message().to_string());
    };
    Template::render("settings/admin/reset_password", &context)
}

/// Password reset form request handler. This route is used by a user who is not logged in
/// and is specifically for users who have forgotten their password.
#[post("/reset_password", data = "<reset_password_form>")]
pub fn reset_password_post(reset_password_form: Form<ResetPasswordForm>) -> Template {
    let result = save_reset_password_form(reset_password_form.into_inner());
    match result {
        Ok(_) => {
            let mut context = ChangePasswordContext::build();
            context.back = Some("/".to_string());
            context.title = Some("Reset Password".to_string());
            context.flash_name = Some("success".to_string());
            let flash_msg = "New password is now saved. Return home to login".to_string();
            context.flash_msg = Some(flash_msg);
            Template::render("settings/admin/reset_password", &context)
        }
        Err(err) => {
            let mut context = ChangePasswordContext::build();
            // set back icon link to network route
            context.back = Some("/".to_string());
            context.title = Some("Reset Password".to_string());
            context.flash_name = Some("error".to_string());
            context.flash_msg = Some(format!("Failed to reset password: {}", err));
            Template::render("settings/admin/reset_password", &context)
        }
    }
}

/// JSON password reset form request handler. This route is used by a user who is not logged in
/// and is specifically for users who have forgotten their password.
#[post("/reset_password", data = "<reset_password_form>")]
pub fn reset_password_form_endpoint(reset_password_form: Json<ResetPasswordForm>) -> Value {
    let result = save_reset_password_form(reset_password_form.into_inner());
    match result {
        Ok(_) => {
            let status = "success".to_string();
            let msg = "New password is now saved. Return home to login.".to_string();
            build_json_response(status, None, Some(msg))
        }
        Err(err) => {
            let status = "error".to_string();
            let msg = format!("{}", err);
            build_json_response(status, None, Some(msg))
        }
    }
}

// HELPERS AND ROUTES FOR /send_password_reset

#[derive(Debug, Serialize)]
pub struct SendPasswordResetContext {
    pub back: Option<String>,
    pub title: Option<String>,
    pub flash_name: Option<String>,
    pub flash_msg: Option<String>,
}

impl SendPasswordResetContext {
    pub fn build() -> SendPasswordResetContext {
        SendPasswordResetContext {
            back: None,
            title: None,
            flash_name: None,
            flash_msg: None,
        }
    }
}

/// Page for users who have forgotten their password.
/// This route is used by a user who is not logged in
/// to initiate the sending of a new password reset.
#[get("/forgot_password")]
pub fn forgot_password_page(flash: Option<FlashMessage>) -> Template {
    let mut context = SendPasswordResetContext::build();
    context.back = Some("/".to_string());
    context.title = Some("Send Password Reset".to_string());
    // check to see if there is a flash message to display
    if let Some(flash) = flash {
        // add flash message contents to the context object
        context.flash_name = Some(flash.kind().to_string());
        context.flash_msg = Some(flash.message().to_string());
    };
    Template::render("settings/admin/forgot_password", &context)
}

/// Send password reset request handler. This route is used by a user who is not logged in
/// and is specifically for users who have forgotten their password. A successful request results
/// in a Scuttlebutt private message being sent to the account of the device admin.
#[post("/send_password_reset")]
pub fn send_password_reset_post() -> Template {
    info!("++ send password reset post");
    let result = password_utils::send_password_reset();
    match result {
        Ok(_) => {
            let mut context = ChangePasswordContext::build();
            context.back = Some("/".to_string());
            context.title = Some("Send Password Reset".to_string());
            context.flash_name = Some("success".to_string());
            let flash_msg =
                "A password reset link has been sent to the admin of this device".to_string();
            context.flash_msg = Some(flash_msg);
            Template::render("settings/admin/forgot_password", &context)
        }
        Err(err) => {
            let mut context = ChangePasswordContext::build();
            context.back = Some("/".to_string());
            context.title = Some("Send Password Reset".to_string());
            context.flash_name = Some("error".to_string());
            context.flash_msg = Some(format!("Failed to send password reset link: {}", err));
            Template::render("settings/admin/forgot_password", &context)
        }
    }
}

// HELPERS AND ROUTES FOR /settings/change_password

#[derive(Debug, Deserialize, FromForm)]
pub struct PasswordForm {
    pub old_password: String,
    pub new_password1: String,
    pub new_password2: String,
}

/// Password save form request handler. This function is for use by a user who is already logged in to change their password.
pub fn save_password_form(password_form: PasswordForm) -> Result<(), PeachWebError> {
    info!(
        "change password!: {} {} {}",
        password_form.old_password, password_form.new_password1, password_form.new_password2
    );
    password_utils::verify_password(&password_form.old_password)?;
    // if the previous line did not throw an error, then the old password is correct
    password_utils::validate_new_passwords(
        &password_form.new_password1,
        &password_form.new_password2,
    )?;
    // if the previous line did not throw an error, then the new password is valid
    password_utils::set_new_password(&password_form.new_password1)?;
    Ok(())
}

/// Change password request handler. This is used by a user who is already logged in.
#[get("/change_password")]
pub fn change_password(flash: Option<FlashMessage>, _auth: Authenticated) -> Template {
    let mut context = ChangePasswordContext::build();
    // set back icon link to network route
    context.back = Some("/settings/admin".to_string());
    context.title = Some("Change Password".to_string());
    // check to see if there is a flash message to display
    if let Some(flash) = flash {
        // add flash message contents to the context object
        context.flash_name = Some(flash.kind().to_string());
        context.flash_msg = Some(flash.message().to_string());
    };
    Template::render("settings/admin/change_password", &context)
}

/// Change password form request handler. This route is used by a user who is already logged in.
#[post("/change_password", data = "<password_form>")]
pub fn change_password_post(password_form: Form<PasswordForm>, _auth: Authenticated) -> Template {
    let result = save_password_form(password_form.into_inner());
    match result {
        Ok(_) => {
            let mut context = ChangePasswordContext::build();
            // set back icon link to network route
            context.back = Some("/settings/admin".to_string());
            context.title = Some("Change Password".to_string());
            context.flash_name = Some("success".to_string());
            context.flash_msg = Some("New password is now saved".to_string());
            // template_dir is set in Rocket.toml
            Template::render("settings/admin/change_password", &context)
        }
        Err(err) => {
            let mut context = ChangePasswordContext::build();
            // set back icon link to network route
            context.back = Some("/settings/admin".to_string());
            context.title = Some("Change Password".to_string());
            context.flash_name = Some("error".to_string());
            context.flash_msg = Some(format!("Failed to save new password: {}", err));
            Template::render("settings/admin/change_password", &context)
        }
    }
}

/// JSON change password form request handler.
#[post("/change_password", data = "<password_form>")]
pub fn save_password_form_endpoint(
    password_form: Json<PasswordForm>,
    _auth: Authenticated,
) -> Value {
    let result = save_password_form(password_form.into_inner());
    match result {
        Ok(_) => {
            let status = "success".to_string();
            let msg = "Your password was successfully changed".to_string();
            build_json_response(status, None, Some(msg))
        }
        Err(err) => {
            let status = "error".to_string();
            let msg = format!("{}", err);
            build_json_response(status, None, Some(msg))
        }
    }
}