pub mod auth;
mod client;
mod util;

use client::{
    email::{EmailMessenger, EmailMessengerError, LocalMailer},
    spice::{Spice, SpiceError},
    store::{
        sql_db::{PgClient, SqliteClient},
        Store, StoreError,
    },
};
use email_address::EmailAddress;
use log::{error, info};
use serde::{Deserialize, Serialize};
use serde_with::{serde_as, DisplayFromStr};
use std::{env::var, str::FromStr, sync::Arc};
use strum_macros::{Display, EnumString, EnumVariantNames};
use time::OffsetDateTime;
use url::Url;
use uuid::Uuid;

pub const ENV_AUTH_STORE_CONN_STRING: &str = "SECD_AUTH_STORE_CONN_STRING";
pub const ENV_EMAIL_MESSENGER: &str = "SECD_EMAIL_MESSENGER";
pub const ENV_EMAIL_MESSENGER_CLIENT_ID: &str = "SECD_EMAIL_MESSENGER_CLIENT_ID";
pub const ENV_EMAIL_MESSENGER_CLIENT_SECRET: &str = "SECD_EMAIL_MESSENGER_CLIENT_SECRET";
pub const ENV_SPICE_SECRET: &str = "SECD_SPICE_SECRET";
pub const ENV_SPICE_SERVER: &str = "SECD_SPICE_SERVER";

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 ADDRESSS_VALIDATION_CODE_SIZE: u8 = 6;
const ADDRESS_VALIDATION_ALLOWS_ATTEMPTS: u8 = 5;
const ADDRESS_VALIDATION_IDENTITY_SURJECTION: bool = true;

pub type AddressId = Uuid;
pub type AddressValidationId = Uuid;
pub type CredentialId = Uuid;
pub type IdentityId = Uuid;
pub type MotifId = Uuid;
pub type PhoneNumber = String;
pub type RefId = Uuid;
pub type SessionToken = String;

#[derive(Debug, derive_more::Display, thiserror::Error)]
pub enum SecdError {
    AddressValidationFailed,
    AddressValidationSessionExchangeFailed,
    AddressValidationExpiredOrConsumed,

    TooManyIdentities,
    IdentityNotFound,

    EmailMessengerError(#[from] EmailMessengerError),
    InvalidEmaillAddress(#[from] email_address::Error),

    FailedToProvideSessionIdentity(String),
    InvalidSession,

    StoreError(#[from] StoreError),
    StoreInitFailure(String),

    FailedToDecodeInput(#[from] hex::FromHexError),

    AuthorizationNotSupported(String),
    SpiceClient(#[from] SpiceError),
    Todo,
}

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

#[derive(Display, Debug, Serialize, Deserialize, EnumString, EnumVariantNames)]
#[strum(ascii_case_insensitive)]
pub enum AuthStore {
    Sqlite { conn: String },
    Postgres { conn: String },
    Redis { conn: String },
}

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

#[serde_with::skip_serializing_none]
#[derive(Debug, Serialize)]
pub struct Address {
    id: AddressId,
    t: AddressType,
    #[serde(with = "time::serde::timestamp")]
    created_at: OffsetDateTime,
}

#[serde_as]
#[serde_with::skip_serializing_none]
#[derive(Debug, Serialize)]
pub struct AddressValidation {
    pub id: AddressValidationId,
    pub identity_id: Option<IdentityId>,
    pub address: Address,
    pub method: AddressValidationMethod,
    #[serde(with = "time::serde::timestamp")]
    pub created_at: OffsetDateTime,
    #[serde(with = "time::serde::timestamp")]
    pub expires_at: OffsetDateTime,
    #[serde(with = "time::serde::timestamp::option")]
    pub revoked_at: Option<OffsetDateTime>,
    #[serde(with = "time::serde::timestamp::option")]
    pub validated_at: Option<OffsetDateTime>,
    pub attempts: i32,
    #[serde_as(as = "serde_with::hex::Hex")]
    hashed_token: Vec<u8>,
    #[serde_as(as = "serde_with::hex::Hex")]
    hashed_code: Vec<u8>,
}

#[derive(Debug, Display, Serialize, EnumString)]
pub enum AddressValidationMethod {
    Email,
    Sms,
    Oauth,
}

#[derive(Debug, Display, Serialize, EnumString)]
pub enum AddressType {
    Email { email_address: Option<EmailAddress> },
    Sms { phone_number: Option<PhoneNumber> },
}

#[derive(Debug, Serialize)]
pub struct Credential {
    pub id: CredentialId,
    pub identity_id: IdentityId,
    pub t: CredentialType,
}

#[serde_as]
#[derive(Debug, Serialize)]
pub enum CredentialType {
    Passphrase {
        key: String,
        value: String,
    },
    Oicd {
        value: String,
    },
    OneTimeCodes {
        codes: Vec<String>,
    },
    Totp {
        #[serde_as(as = "DisplayFromStr")]
        url: Url,
        code: String,
    },
    WebAuthn {
        value: String,
    },
}

#[serde_with::skip_serializing_none]
#[derive(Debug, Serialize)]
pub struct Identity {
    pub id: IdentityId,
    pub address_validations: Vec<AddressValidation>,
    pub credentials: Vec<Credential>,
    pub rules: Vec<String>, // TODO: rules for (e.g. mfa reqs)
    pub metadata: Option<String>,
    #[serde(with = "time::serde::timestamp")]
    pub created_at: OffsetDateTime,
    #[serde(with = "time::serde::timestamp::option")]
    pub deleted_at: Option<OffsetDateTime>,
}

#[serde_as]
#[serde_with::skip_serializing_none]
#[derive(Debug, Serialize)]
pub struct Session {
    pub identity_id: IdentityId,
    #[serde_as(as = "serde_with::hex::Hex")]
    #[serde(skip_serializing_if = "Vec::is_empty")]
    pub token: Vec<u8>,
    #[serde(with = "time::serde::timestamp")]
    pub created_at: OffsetDateTime,
    #[serde(with = "time::serde::timestamp")]
    pub expired_at: OffsetDateTime,
    #[serde(with = "time::serde::timestamp::option")]
    pub revoked_at: Option<OffsetDateTime>,
}

impl Secd {
    /// init
    ///
    /// Initialize SecD with the specified configuration, established the necessary
    /// constraints, persistance stores, and options.
    pub async fn init(z_schema: Option<&str>) -> Result<Self, SecdError> {
        let auth_store = AuthStore::from(var(ENV_AUTH_STORE_CONN_STRING).ok());
        let email_messenger = AuthEmailMessenger::from_str(
            &var(ENV_EMAIL_MESSENGER).unwrap_or(AuthEmailMessenger::Local.to_string()),
        )
        .expect("unreachable f4ad0f48-0812-427f-b477-0f9c67bb69c5");
        let email_messenger_client_id = var(ENV_EMAIL_MESSENGER_CLIENT_ID).ok();
        let email_messenger_client_secret = var(ENV_EMAIL_MESSENGER_CLIENT_SECRET).ok();

        info!("starting client with auth_store: {:?}", auth_store);
        info!("starting client with email_messenger: {:?}", auth_store);

        let store = match auth_store {
            AuthStore::Sqlite { conn } => {
                if z_schema.is_some() {
                    return Err(SecdError::AuthorizationNotSupported(
                        "sqlite is currently unsupported".into(),
                    ));
                }

                SqliteClient::new(
                    sqlx::sqlite::SqlitePoolOptions::new()
                        .connect(&conn)
                        .await
                        .map_err(|e| {
                            SecdError::StoreInitFailure(format!("failed to init sqlite: {}", e))
                        })?,
                )
                .await
            }
            AuthStore::Postgres { conn } => {
                PgClient::new(
                    sqlx::postgres::PgPoolOptions::new()
                        .connect(&conn)
                        .await
                        .map_err(|e| {
                            SecdError::StoreInitFailure(format!("failed to init sqlite: {}", e))
                        })?,
                )
                .await
            }
            rest @ _ => {
                error!(
                    "requested an AuthStore which has not yet been implemented: {:?}",
                    rest
                );
                unimplemented!()
            }
        };

        let email_sender = match email_messenger {
            AuthEmailMessenger::Local => LocalMailer {},
            _ => unimplemented!(),
        };

        let spice = match z_schema {
            Some(schema) => {
                let c: Arc<Spice> = Arc::new(Spice::new().await);
                c.write_schema(schema)
                    .await
                    .expect("failed to write authorization schema".into());
                Some(c)
            }
            None => None,
        };

        Ok(Secd {
            store,
            email_messenger: Arc::new(email_sender),
            spice,
        })
    }
}