mod client;
mod command;
mod util;

use std::sync::Arc;

use clap::ValueEnum;
use client::{EmailMessenger, EmailMessengerError, Store};
use derive_more::Display;
use email_address::EmailAddress;
use serde::{Deserialize, Serialize};
use sqlx::FromRow;
use strum_macros::{EnumString, EnumVariantNames};
use time::OffsetDateTime;
use url::Url;
use util::get_oauth_identity_data;
use uuid::Uuid;

const SESSION_SIZE_BYTES: usize = 32;
const SESSION_DURATION: i64 = 60 /* seconds*/ * 60 /* minutes */ * 24 /* hours */ * 360 /* days */;
const EMAIL_VALIDATION_DURATION: i64 = 60 /* seconds*/ * 15 /* minutes */;
const VALIDATION_CODE_SIZE: usize = 6;

const INTERNAL_ERR_MSG: &str = "It seems an invariant was borked or something non-deterministic happened. Please file a bug with secd.";

#[derive(sqlx::FromRow, Debug, Serialize)]
pub struct ApiKey {
    pub public_key: String,
    pub private_key: String,
}

#[derive(sqlx::FromRow, Debug, Serialize)]
pub struct Authorization {
    session: Session,
}

#[derive(sqlx::FromRow, Debug, Serialize)]
pub struct Identity {
    #[sqlx(rename = "identity_public_id")]
    id: Uuid,
    #[serde(skip_serializing_if = "Option::is_none")]
    data: Option<String>,
    created_at: OffsetDateTime,
    #[serde(skip_serializing_if = "Option::is_none")]
    deleted_at: Option<OffsetDateTime>,
}

#[derive(sqlx::FromRow, Debug, Serialize)]
pub struct Session {
    #[sqlx(rename = "identity_public_id")]
    pub identity_id: IdentityId,
    #[serde(skip_serializing_if = "Option::is_none")]
    #[sqlx(default)]
    pub secret: Option<SessionSecret>,
    #[serde(with = "time::serde::timestamp")]
    pub created_at: OffsetDateTime,
    #[serde(with = "time::serde::timestamp")]
    pub expires_at: OffsetDateTime,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub revoked_at: Option<OffsetDateTime>,
}

#[async_trait::async_trait]
trait Validation {
    fn expired(&self) -> bool;
    fn is_validated(&self) -> bool;
    async fn find_associated_identities(
        &self,
        store: Arc<dyn Store + Send + Sync>,
    ) -> anyhow::Result<Option<Identity>>;
    async fn validate(
        &mut self,
        i: &Identity,
        store: Arc<dyn Store + Send + Sync>,
    ) -> anyhow::Result<()>;
}

#[async_trait::async_trait]
impl Validation for EmailValidation {
    fn expired(&self) -> bool {
        let now = OffsetDateTime::now_utc();
        self.expired_at < now
            || self.revoked_at.map(|t| t < now).unwrap_or(false)
            || self.deleted_at.map(|t| t < now).unwrap_or(false)
    }
    fn is_validated(&self) -> bool {
        self.validated_at
            .map(|t| t >= OffsetDateTime::now_utc())
            .unwrap_or(false)
    }
    async fn find_associated_identities(
        &self,
        store: Arc<dyn Store + Send + Sync>,
    ) -> anyhow::Result<Option<Identity>> {
        store.find_identity(None, Some(&self.email_address)).await
    }
    async fn validate(
        &mut self,
        i: &Identity,
        store: Arc<dyn Store + Send + Sync>,
    ) -> anyhow::Result<()> {
        self.identity_id = Some(i.id);
        self.validated_at = Some(OffsetDateTime::now_utc());
        store.write_email_validation(&self).await?;
        Ok(())
    }
}

#[async_trait::async_trait]
impl Validation for OauthValidation {
    fn expired(&self) -> bool {
        let now = OffsetDateTime::now_utc();
        self.revoked_at.map(|t| t < now).unwrap_or(false)
            || self.deleted_at.map(|t| t < now).unwrap_or(false)
    }
    fn is_validated(&self) -> bool {
        self.validated_at
            .map(|t| t >= OffsetDateTime::now_utc())
            .unwrap_or(false)
    }
    async fn find_associated_identities(
        &self,
        store: Arc<dyn Store + Send + Sync>,
    ) -> anyhow::Result<Option<Identity>> {
        let oauth_identity = get_oauth_identity_data(&self).await?;

        let identity = store
            .find_identity(None, oauth_identity.email.as_deref())
            .await?;

        let now = OffsetDateTime::now_utc();
        if let Some(email) = oauth_identity.email.clone() {
            let identity = identity.unwrap_or(Identity {
                id: Uuid::new_v4(),
                data: None,
                created_at: OffsetDateTime::now_utc(),
                deleted_at: None,
            });
            store.write_identity(&identity).await?;
            store.write_email(&email).await?;
            store
                .write_email_validation(&EmailValidation {
                    id: Some(Uuid::new_v4()),
                    identity_id: Some(identity.id),
                    email_address: email,
                    code: None,
                    is_oauth_derived: true,
                    created_at: now,
                    expired_at: now,
                    validated_at: Some(now),
                    revoked_at: None,
                    deleted_at: None,
                })
                .await?;
            Ok(Some(identity))
        } else {
            Ok(identity)
        }
    }
    async fn validate(
        &mut self,
        i: &Identity,
        store: Arc<dyn Store + Send + Sync>,
    ) -> anyhow::Result<()> {
        self.identity_id = Some(i.id);
        self.validated_at = Some(OffsetDateTime::now_utc());
        store.write_oauth_validation(&self).await?;
        Ok(())
    }
}

#[derive(Debug, EnumString)]
pub enum ValidationType {
    Email,
    Oauth,
}

#[derive(sqlx::FromRow, Debug)]
pub struct EmailValidation {
    #[sqlx(rename = "email_validation_public_id")]
    id: Option<Uuid>,
    #[sqlx(rename = "identity_public_id")]
    identity_id: Option<IdentityId>,
    #[sqlx(rename = "address")]
    email_address: String,
    code: Option<String>,
    is_oauth_derived: bool,
    created_at: OffsetDateTime,
    expired_at: OffsetDateTime,
    validated_at: Option<OffsetDateTime>,
    revoked_at: Option<OffsetDateTime>,
    deleted_at: Option<OffsetDateTime>,
}

#[derive(Debug)]
pub struct OauthValidation {
    id: Option<Uuid>,
    identity_id: Option<IdentityId>,
    oauth_provider: OauthProvider,
    access_token: Option<String>,
    raw_response: Option<String>,
    created_at: OffsetDateTime,
    validated_at: Option<OffsetDateTime>,
    revoked_at: Option<OffsetDateTime>,
    deleted_at: Option<OffsetDateTime>,
}

#[derive(Debug, Clone)]
pub struct OauthProvider {
    pub name: OauthProviderName,
    pub flow: Option<String>,
    pub base_url: Url,
    pub response: OauthResponseType,
    pub default_scope: String,
    pub client_id: String,
    pub client_secret: String,
    pub redirect_url: Url,
    pub created_at: OffsetDateTime,
    pub deleted_at: Option<OffsetDateTime>,
}

#[derive(Debug, Display, Clone, Copy, ValueEnum, EnumString)]
pub enum OauthResponseType {
    Code,
    IdToken,
    None,
    Token,
}

// TODO: feature gate ValueEnum since it's only needed for iam builds
#[derive(Copy, Display, Clone, Debug, ValueEnum, EnumString)]
pub enum OauthProviderName {
    Amazon,
    Apple,
    Dropbox,
    Facebook,
    Github,
    Gitlab,
    Google,
    Instagram,
    LinkedIn,
    Microsoft,
    Paypal,
    Reddit,
    Spotify,
    Strava,
    Stripe,
    Twitch,
    Twitter,
    WeChat,
}

#[derive(Display, Debug, Serialize, Deserialize, EnumString, EnumVariantNames)]
#[strum(ascii_case_insensitive)]
pub enum AuthStore {
    Sqlite,
    Postgres,
    MySql,
    Mongo,
    Dynamo,
    Redis,
}

#[derive(Display, Debug, Serialize, Deserialize, EnumString, EnumVariantNames)]
#[strum(ascii_case_insensitive)]
pub enum AuthEmail {
    LocalStub,
    Ses,
    Mailgun,
    Sendgrid,
}

pub type IdentityId = Uuid;
pub type SessionSecret = String;
pub type SessionSecretHash = String;
pub type ValidationRequestId = Uuid;
pub type ValidationSecretCode = String;
pub type OauthRedirectAuthUrl = Url;

#[derive(Debug, derive_more::Display, thiserror::Error)]
pub enum SecdError {
    EmailSendError(#[from] EmailMessengerError),
    EmailValidationExpiryOverflow,
    EmailValidationRequestError,
    OauthValidationRequestError,
    IdentityIdShouldExistInvariant,
    InitializationFailure(sqlx::Error),
    InvalidCode,
    InvalidEmailAddress,
    InputValidation(String),
    InternalError(String),
    NotImplemented(String),
    SessionExpiryOverflow,
    Unauthenticated,
    Todo,
}

pub struct Secd {
    store: Arc<dyn Store + Send + Sync + 'static>,
    email_messenger: Arc<dyn EmailMessenger + Send + Sync + 'static>,
}

impl Secd {
    /// get_identity
    ///
    /// Return all information associated with the identity id.
    pub async fn get_identity(&self, identity: IdentityId) -> Result<Identity, SecdError> {
        unimplemented!()
    }
    /// get_authorization
    ///
    /// Return the authorization for this session. If the session is
    /// invalid, expired or otherwise unauthenticated, an error will
    /// be returned.
    pub async fn get_authorization(
        &self,
        secret: SessionSecret,
    ) -> Result<Authorization, SecdError> {
        match self.store.read_session(&secret).await {
            Ok(session)
                if session.expires_at > OffsetDateTime::now_utc()
                    || session.revoked_at > Some(OffsetDateTime::now_utc()) =>
            {
                Ok(Authorization { session })
            }
            Ok(_) => Err(SecdError::Unauthenticated),
            Err(_e) => Err(SecdError::Todo),
        }
    }
    /// revoke_session
    ///
    /// Revokes a session such that it may no longer be used to authenticate
    /// the associated identity.
    pub async fn revoke_session(&self, secret_hash: SessionSecretHash) -> Result<(), SecdError> {
        unimplemented!()
    }
    /// revoke_identity
    ///
    /// Soft delete an identity such that all associated resources are
    /// deleted as well.
    ///
    /// NOTE: This operation cannot be undone. Although it may not be undone
    /// a separate call to delete_identity is required to cleanup necessary
    /// resources.
    ///
    /// You may configure secd to periodically clean all revoked
    /// identities and associated resources with AUTOCLEAN_REVOKED.
    pub async fn revoke_identity(&self, identity_id: IdentityId) -> Result<(), SecdError> {
        unimplemented!()
    }
    /// delete_identity
    ///
    /// Delete an identity and all associated resources (e.g. session,
    /// authorization structures, etc...). This is a hard delete and permanently
    /// removes all stored information.
    ///
    /// NOTE: An identity _must_ be revoked before it can be deleted. Otherwise,
    /// secd will return an error.
    pub async fn delete_identity(&self, identity_id: IdentityId) -> Result<(), SecdError> {
        unimplemented!()
    }

    // register service
    // register service_action(service_id, action)
    // list services
    // list service actions

    // create permission
    // create group (name, identities)
    // create role (name, permissios)
    // list group
    // list role
    // list permission
    // describe group
    // describe role
    // describe permission
    // add_identity_to_group
    // remove_identity_from_group
    // add_permission_to_role
    // remove_permission_from_role
    // attach_role_to_group
    // attach_permission_to_group (just creates single role and attaches it)
}