use std::str::FromStr;

use crate::{
    client::{
        email::{EmailValidationMessage, Sendable},
        store::{
            AddressLens, AddressValidationLens, IdentityLens, SessionLens, Storable, StoreError,
        },
    },
    util, Address, AddressType, AddressValidation, AddressValidationId, AddressValidationMethod,
    Credential, CredentialType, Identity, PhoneNumber, Secd, SecdError, Session, SessionToken,
    ADDRESSS_VALIDATION_CODE_SIZE, ADDRESS_VALIDATION_ALLOWS_ATTEMPTS,
    ADDRESS_VALIDATION_IDENTITY_SURJECTION, EMAIL_VALIDATION_DURATION,
};
use email_address::EmailAddress;
use log::warn;
use rand::Rng;
use time::{Duration, OffsetDateTime};
use uuid::Uuid;

impl Secd {
    pub async fn validate_email(
        &self,
        email_address: &str,
        identity_id: Option<Uuid>,
    ) -> Result<AddressValidation, SecdError> {
        let email_address = EmailAddress::from_str(email_address)?;
        // record address (idempotent operation)
        let mut address = Address {
            id: Uuid::new_v4(),
            t: AddressType::Email {
                email_address: Some(email_address.clone()),
            },
            created_at: OffsetDateTime::now_utc(),
        };

        if let Err(StoreError::IdempotentCheckAlreadyExists) =
            address.write(self.store.clone()).await
        {
            address = Address::find(
                self.store.clone(),
                &AddressLens {
                    id: None,
                    t: Some(&AddressType::Email {
                        email_address: Some(email_address.clone()),
                    }),
                },
            )
            .await?
            .into_iter()
            .next()
            .ok_or(SecdError::AddressValidationFailed)?;
        }

        let secret = hex::encode(rand::thread_rng().gen::<[u8; 32]>());
        let code: String = vec![0; ADDRESSS_VALIDATION_CODE_SIZE as usize]
            .into_iter()
            .map(|_| char::from_digit(rand::thread_rng().gen_range(0..=9), 10).unwrap())
            .collect();

        let mut validation = AddressValidation {
            id: Uuid::new_v4(),
            identity_id,
            address,
            method: AddressValidationMethod::Email,
            created_at: OffsetDateTime::now_utc(),
            expires_at: OffsetDateTime::now_utc()
                .checked_add(Duration::new(EMAIL_VALIDATION_DURATION, 0))
                .ok_or(SecdError::Todo)?,
            revoked_at: None,
            validated_at: None,
            attempts: 0,
            hashed_token: util::hash(&secret.as_bytes()),
            hashed_code: util::hash(&code.as_bytes()),
        };

        validation.write(self.store.clone()).await?;

        let msg =EmailValidationMessage {
            recipient: email_address.clone(),
            subject: "Confirm Your Email".into(),
            body: format!("This is an email validation message. Click this link [{:?}?s={}] or use the code [{}]", validation.id, secret, code),
        };

        match msg.send().await {
            Ok(_) => { /* TODO: Write down the message*/ }
            Err(e) => {
                validation.revoked_at = Some(OffsetDateTime::now_utc());
                validation.write(self.store.clone()).await?;
                return Err(SecdError::EmailMessengerError(e));
            }
        }

        Ok(validation)
    }
    pub async fn validate_sms(
        &self,
        phone_number: &PhoneNumber,
    ) -> Result<AddressValidation, SecdError> {
        todo!()
    }
    pub async fn complete_address_validation(
        &self,
        validation_id: &AddressValidationId,
        plaintext_token: Option<String>,
        plaintext_code: Option<String>,
    ) -> Result<Session, SecdError> {
        let mut validation = AddressValidation::find(
            self.store.clone(),
            &AddressValidationLens {
                id: Some(validation_id),
            },
        )
        .await?
        .into_iter()
        .next()
        .ok_or(SecdError::AddressValidationFailed)?;

        if validation.validated_at.is_some() {
            return Err(SecdError::AddressValidationExpiredOrConsumed);
        }

        validation.attempts += 1;
        if validation.attempts > ADDRESS_VALIDATION_ALLOWS_ATTEMPTS as i32 {
            warn!(
                "validation failed: Too many validation attempts were tried for validation {:?}",
                validation.id
            );
            validation.write(self.store.clone()).await?;
            return Err(SecdError::AddressValidationExpiredOrConsumed);
        }

        let hashed_token = plaintext_token.map(|s| util::hash(s.as_bytes()));
        let hashed_code = plaintext_code.map(|c| util::hash(c.as_bytes()));

        let mut warn_msg = None;
        match (hashed_token, hashed_code) {
            (None, None) => {
                warn_msg = Some("neither token nor hash was provided during the address validation session exchange");
            }
            (Some(t), None) => {
                if validation.hashed_token != t {
                    warn_msg =
                        Some("the provided token does not match the address validation token");
                }
            }
            (None, Some(c)) => {
                if validation.hashed_code != c {
                    warn_msg = Some("the provided code does not match the address validation code");
                }
            }
            (Some(t), Some(c)) => {
                if validation.hashed_token != t || validation.hashed_code != c {
                    warn_msg = Some("the provided token and code must both match the address validation token and code");
                }
            }
        };

        if let Some(msg) = warn_msg {
            warn!("validation failed: {}", msg);
            validation.write(self.store.clone()).await?;
            return Err(SecdError::AddressValidationSessionExchangeFailed);
        }

        let identity = Identity::find(
            self.store.clone(),
            &IdentityLens {
                id: None,
                address_type: Some(&validation.address.t),
                validated_address: Some(true),
                session_token_hash: None,
            },
        )
        .await?;

        if !ADDRESS_VALIDATION_IDENTITY_SURJECTION && identity.len() > 1 {
            warn!("validation failed: identity validation surjection disallowed");
            validation.write(self.store.clone()).await?;
            return Err(SecdError::TooManyIdentities);
        }

        let mut identity = identity.into_iter().next();
        if identity.is_none() {
            let i = Identity {
                id: Uuid::new_v4(),
                address_validations: vec![],
                credentials: vec![],
                rules: vec![],
                metadata: None,
                created_at: OffsetDateTime::now_utc(),
                deleted_at: None,
            };
            i.write(self.store.clone()).await?;
            identity = Some(i);
        }

        assert!(identity.is_some());

        // If the validation was attached to another identity, unless surjection is allowed, it cannot be recorded.
        if !ADDRESS_VALIDATION_IDENTITY_SURJECTION
            && validation.identity_id.is_some()
            && identity.as_ref().map(|i| i.id) != validation.identity_id
        {
            warn!("validation failed: identity validation surjection is disallowed, but found existing identity for another account");
            validation.write(self.store.clone()).await?;
            return Err(SecdError::TooManyIdentities);
        }

        validation.identity_id = identity.map(|i| i.id);
        validation.validated_at = Some(OffsetDateTime::now_utc());
        validation.write(self.store.clone()).await?;

        let session = Session::new(validation.identity_id.expect("unreachable d3ded289-72eb-4a42-a37d-f5c9c697cc61 [assert(identity.is_some()) prevents this]"))?;
        session.write(self.store.clone()).await?;

        Ok(session)
    }
    pub async fn create_credential(
        &self,
        t: CredentialType,
        key: String,
        value: Option<String>,
    ) -> Result<Credential, SecdError> {
        todo!()
    }

    pub async fn validate_credential(
        &self,
        t: CredentialType,
        key: String,
        value: Option<String>,
    ) -> Result<Session, SecdError> {
        todo!()
    }

    pub async fn get_session(&self, t: &SessionToken) -> Result<Session, SecdError> {
        let token = hex::decode(t)?;
        let mut session = Session::find(
            self.store.clone(),
            &SessionLens {
                token_hash: Some(&util::hash(&token)),
                identity_id: None,
            },
        )
        .await?;
        assert!(session.len() <= 1, "get session failed: multiple sessions found for a single token. This is very _very_ bad.");

        if session.is_empty() {
            return Err(SecdError::InvalidSession);
        } else {
            let mut session = session.swap_remove(0);
            session.token = token;
            Ok(session)
        }
    }

    pub async fn get_identity(&self, i: &SessionToken) -> Result<Identity, SecdError> {
        let token_hash = util::hash(&hex::decode(i)?);
        let mut i = Identity::find(
            self.store.clone(),
            &IdentityLens {
                id: None,
                address_type: None,
                validated_address: None,
                session_token_hash: Some(token_hash),
            },
        )
        .await?;

        assert!(
            i.len() <= 1,
            "The provided id refers to more than one identity. This is very _very_ bad."
        );

        if i.is_empty() {
            return Err(SecdError::IdentityNotFound);
        } else {
            Ok(i.swap_remove(0))
        }
    }

    pub async fn revoke_session(&self, session: &mut Session) -> Result<(), SecdError> {
        session.revoked_at = Some(OffsetDateTime::now_utc());
        session.write(self.store.clone()).await?;
        Ok(())
    }
}