#[cfg(feature = "ssr")]
use anyhow::anyhow;

#[cfg(feature = "ssr")]
use argon2::{
    password_hash::{rand_core::OsRng, SaltString},
    Argon2, PasswordHash, PasswordHasher, PasswordVerifier,
};

use derive_more::{derive::Display, From};

#[cfg(feature = "ssr")]
use rand::{distributions::Alphanumeric, Rng};
use serde::{ser::SerializeStruct, Deserialize, Serialize};
use thiserror::Error;

/// A uniquely identifiable blog of blog blog.
#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Deserialize)]
pub struct User {
    id: uuid::Uuid,
    email: EmailAddress,
    #[cfg(feature = "ssr")]
    password: Password,
    verified: Verified,
}

impl User {
    pub fn new(
        id: uuid::Uuid,
        email: EmailAddress,
        #[cfg(feature = "ssr")] password: Password,
        verified: Verified,
    ) -> Self {
        Self {
            id,
            email,
            #[cfg(feature = "ssr")]
            password,
            verified,
        }
    }

    pub fn id(&self) -> &uuid::Uuid {
        &self.id
    }

    pub fn email(&self) -> &EmailAddress {
        &self.email
    }

    #[cfg(feature = "ssr")]
    pub fn password(&self) -> &Password {
        &self.password
    }

    pub fn verified(&self) -> &Verified {
        &self.verified
    }
}

impl Serialize for User {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: serde::Serializer,
    {
        let mut state = serializer.serialize_struct("User", 3)?;
        state.serialize_field("id", &self.id())?;
        state.serialize_field("email", &self.email())?;
        state.serialize_field("verified", &self.verified())?;
        state.end()
    }
}

#[cfg(feature = "ssr")]
#[derive(Clone, Display, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Deserialize)]
#[serde(from = "String")]
pub struct ActivationToken(String);

#[cfg(feature = "ssr")]
impl From<String> for ActivationToken {
    fn from(value: String) -> Self {
        Self(value)
    }
}

#[cfg(feature = "ssr")]
impl From<&str> for ActivationToken {
    fn from(value: &str) -> Self {
        Self(value.to_string())
    }
}

#[cfg(feature = "ssr")]
impl ActivationToken {
    pub fn new() -> Self {
        let token: String = rand::thread_rng()
            .sample_iter(&Alphanumeric)
            .take(11)
            .map(char::from)
            .collect();

        Self(token)
    }
}

#[cfg(feature = "ssr")]
#[derive(Clone, Display, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Deserialize)]
#[serde(from = "String")]
pub struct PasswordResetToken(String);

#[cfg(feature = "ssr")]
impl From<String> for PasswordResetToken {
    fn from(value: String) -> Self {
        Self(value)
    }
}

#[cfg(feature = "ssr")]
impl From<&str> for PasswordResetToken {
    fn from(value: &str) -> Self {
        Self(value.to_string())
    }
}

#[cfg(feature = "ssr")]
impl PasswordResetToken {
    pub fn new() -> Self {
        let token: String = rand::thread_rng()
            .sample_iter(&Alphanumeric)
            .take(24)
            .map(char::from)
            .collect();

        Self(token)
    }
}

#[cfg(feature = "ssr")]
#[derive(Debug, Error)]
pub enum ResetPasswordError {
    #[error("The reset token is no longer valid.")]
    NotFound,
    #[error(transparent)]
    Unknown(#[from] anyhow::Error),
    // to be extended as new error scenarios are introduced
}

#[derive(
    Clone, Copy, Display, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize,
)]
#[serde(from = "bool")]
pub struct Verified(bool);

impl From<bool> for Verified {
    fn from(value: bool) -> Self {
        Self::new(value)
    }
}

impl Verified {
    pub fn new(value: bool) -> Self {
        Self(value)
    }

    pub fn is_verified(&self) -> bool {
        self.0
    }
}

impl From<Verified> for bool {
    fn from(value: Verified) -> Self {
        value.0
    }
}

#[derive(Clone, Display, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
#[serde(try_from = "String")]
/// A valid email address.
pub struct EmailAddress(String);

impl TryFrom<String> for EmailAddress {
    type Error = EmailAddressError;
    fn try_from(value: String) -> Result<Self, Self::Error> {
        Self::new(&value)
    }
}

impl TryFrom<&str> for EmailAddress {
    type Error = EmailAddressError;
    fn try_from(value: &str) -> Result<Self, Self::Error> {
        Self::new(value)
    }
}

#[derive(Clone, Debug, Error)]
#[error("{invalid_email} is not a valid email address")]
pub struct EmailAddressError {
    pub invalid_email: String,
}

impl From<EmailAddressError> for String {
    fn from(value: EmailAddressError) -> Self {
        format!("{}", value)
    }
}

impl EmailAddress {
    pub fn new(raw: &str) -> Result<Self, EmailAddressError> {
        let trimmed = raw.trim();
        Self::validate_email_address(trimmed)?;
        Ok(Self(trimmed.to_string()))
    }

    fn validate_email_address(email: &str) -> Result<(), EmailAddressError> {
        if !email.contains('@') {
            return Err(EmailAddressError {
                invalid_email: email.to_string(),
            });
        }

        if email.contains(' ') {
            return Err(EmailAddressError {
                invalid_email: email.to_string(),
            });
        }

        if email.len() < 3 {
            // a@b is technically valid, a@ or @b is not
            return Err(EmailAddressError {
                invalid_email: email.to_string(),
            });
        }

        use validator::ValidateEmail;
        if !email.validate_email() {
            return Err(EmailAddressError {
                invalid_email: email.to_string(),
            });
        }

        Ok(())
    }
}

#[cfg(feature = "ssr")]
#[derive(Clone, Display, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Deserialize)]
#[serde(try_from = "String")]
/// A valid password.
pub struct Password {
    hashed_password: String,
}

#[cfg(feature = "ssr")]
impl TryFrom<String> for Password {
    type Error = PasswordError;
    fn try_from(value: String) -> Result<Self, Self::Error> {
        Self::new(&value)
    }
}

#[cfg(feature = "ssr")]
impl TryFrom<&str> for Password {
    type Error = PasswordError;
    fn try_from(value: &str) -> Result<Self, Self::Error> {
        Self::new(value)
    }
}

#[cfg(feature = "ssr")]
impl Password {
    pub fn new(password: &str) -> Result<Self, PasswordError> {
        // password restrictions
        if password.len() < 6 {
            return Err(PasswordError::TooShort);
        }

        // Do we need to protect people from being stupid?

        let salt = SaltString::generate(&mut OsRng);
        let hashed_password = Argon2::default()
            .hash_password(password.as_bytes(), &salt)
            .map_err(|e| PasswordError::Unknown(anyhow!(e)))?
            .to_string();

        Ok(Self { hashed_password })
    }

    pub fn new_hashed(hashed_password: &str) -> Self {
        Self {
            hashed_password: hashed_password.to_string(),
        }
    }

    pub fn verify(&self, password: &str) -> Result<(), anyhow::Error> {
        let hash = PasswordHash::new(&self.hashed_password).map_err(|e| anyhow!(e))?;
        Argon2::default()
            .verify_password(password.as_bytes(), &hash)
            .map_err(|e| anyhow!(e))
    }
}

#[cfg(feature = "ssr")]
#[derive(Debug, Error)]
pub enum PasswordError {
    #[error("Password must be at least 6 characters long.")]
    TooShort,
    #[error(transparent)]
    Unknown(#[from] anyhow::Error),
    // to be extended as new error scenarios are introduced
}

#[cfg(feature = "ssr")]
/// The fields required by the domain to create a [User].
#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, From)]
pub struct CreateUserRequest {
    email: EmailAddress,
    password: Password,
}

#[cfg(feature = "ssr")]
impl CreateUserRequest {
    pub fn new(email: EmailAddress, password: Password) -> Self {
        Self { email, password }
    }

    pub fn email(&self) -> &EmailAddress {
        &self.email
    }

    pub fn password(&self) -> &Password {
        &self.password
    }
}

#[cfg(feature = "ssr")]
#[derive(Debug, Error)]
pub enum CreateUserError {
    #[error("User with email {email} already exists")]
    Duplicate { email: EmailAddress },
    #[error(transparent)]
    Unknown(#[from] anyhow::Error),
    // to be extended as new error scenarios are introduced
}

#[cfg(feature = "ssr")]
/// The fields required by the domain to create a [User].
#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, From)]
pub struct UserLoginRequest {
    email: EmailAddress,
    password: String,
}

#[cfg(feature = "ssr")]
impl UserLoginRequest {
    pub fn new(email: EmailAddress, password: String) -> Self {
        Self { email, password }
    }

    pub fn email(&self) -> &EmailAddress {
        &self.email
    }

    pub fn password(&self) -> &str {
        &self.password
    }
}

#[cfg(feature = "ssr")]
pub struct UpdateUserRequest {
    email: Option<EmailAddress>,
    password: Option<Password>,
    verified: Option<Verified>,
}

#[cfg(feature = "ssr")]
impl UpdateUserRequest {
    pub fn new() -> Self {
        Self {
            email: None,
            password: None,
            verified: None,
        }
    }

    pub fn email(&self) -> Option<&EmailAddress> {
        self.email.as_ref()
    }

    pub fn set_email(mut self, email: EmailAddress) -> Self {
        self.email = Some(email);
        self
    }

    pub fn set_password(mut self, password: Password) -> Self {
        self.password = Some(password);
        self
    }

    pub fn password(&self) -> Option<&Password> {
        self.password.as_ref()
    }

    pub fn set_verified(mut self, verified: Verified) -> Self {
        self.verified = Some(verified);
        self
    }

    pub fn verified(&self) -> Option<&Verified> {
        self.verified.as_ref()
    }
}

#[cfg(feature = "ssr")]
#[derive(Debug, Error)]
pub enum UpdateUserError {
    #[error("User with email {email} already exists")]
    Duplicate { email: EmailAddress },
    #[error(transparent)]
    Unknown(#[from] anyhow::Error),
    // to be extended as new error scenarios are introduced
}

#[cfg(feature = "ssr")]
#[derive(Debug, Error)]
pub enum DeleteUserError {
    #[error("User with id {id} not found")]
    NotFound { id: uuid::Uuid },
    #[error(transparent)]
    Unknown(#[from] anyhow::Error),
    // to be extended as new error scenarios are introduced
}

#[cfg(feature = "ssr")]
#[derive(Debug, Error)]
pub enum ActivateUserError {
    #[error("Token {token} is invalid")]
    NotFound { token: ActivationToken },
    #[error(transparent)]
    Unknown(#[from] anyhow::Error),
    // to be extended as new error scenarios are introduced
}

#[cfg(feature = "ssr")]
#[derive(Debug, Error)]
pub enum UserLoginError {
    #[error("User with email {email} not found")]
    NotFound { email: EmailAddress },
    #[error("User with email {email} not verified")]
    NotActive { email: EmailAddress },
    #[error(transparent)]
    Unknown(#[from] anyhow::Error),
    // to be extended as new error scenarios are introduced
}