use std::{sync::mpsc::Sender, time::SystemTime};

use crate::{
    db::{insert_new_user, DbPool, NewUserEntity, UserEntity},
    models::{ApiResponse, AppError, Session},
    requests::AppState,
    services::{
        self, auth_token::generate_new_user_token, hash_password, CachePool,
        UserConfirmationMessage,
    },
};
use axum::{
    debug_handler,
    extract::State,
    response::{IntoResponse, Response},
    Json,
};
use http::StatusCode;
use pasetors::{keys::SymmetricKey, version4::V4};
use tracing::debug;

use super::models::{UserRegistrationRequest, UserRegistrationResponse};

#[debug_handler]
pub async fn user_registration_post_handler(
    State(state): State<AppState>,
    Json(request): Json<UserRegistrationRequest>,
) -> Result<Response, AppError> {
    let env = state.env();

    register_new_user_request(
        request,
        state.db_pool(),
        state.cache_pool(),
        env.token_key(),
        env.send_verification_email(),
        env.email_sender(),
    )
    .await
}

async fn register_new_user_request(
    body: UserRegistrationRequest,
    db_pool: &DbPool,
    cache_pool: &CachePool,
    signing_key: &SymmetricKey<V4>,
    send_verification_email: bool,
    email_sender: &Sender<UserConfirmationMessage>,
) -> Result<Response, AppError> {
    debug!(?body, send_verification_email);

    let UserRegistrationRequest {
        username,
        password,
        email,
        name,
    } = body;

    let hashed_password = hash_password(password);

    let new_user = NewUserEntity {
        username: username.clone(),
        password: hashed_password.to_string(),
        email,
        name,
    };

    let UserEntity {
        id: user_id,
        name,
        email,
        ..
    } = insert_new_user(db_pool, new_user).await.map_err(|err| {
        if err.is_duplicate_record() {
            AppError::duplicate_record(
                "There is already an account associated with this username or email address.",
            )
        } else {
            err
        }
    })?;

    let (verification_token, token_id, expires_at) = generate_new_user_token(signing_key, user_id);

    let new_user_session = Session {
        user_id,
        username,
        created_at: SystemTime::now(),
        expires_at,
    };

    let expires_in = expires_at.duration_since(SystemTime::now()).unwrap();
    services::user_session::store_user_session(
        cache_pool,
        token_id,
        new_user_session,
        Some(expires_in),
    )
    .await?;

    let response_body = if send_verification_email {
        let new_user_confirmation_message = UserConfirmationMessage {
            email,
            name,
            verification_token: verification_token.clone(),
        };

        let _ = email_sender
            .send(new_user_confirmation_message)
            .inspect_err(|err| {
                eprintln!("Got the rollowing error while sending across the channel: {err}");
            });

        UserRegistrationResponse {
            id: user_id,
            expires_at,
            verification_token: None,
        }
    } else {
        UserRegistrationResponse {
            id: user_id,
            expires_at,
            verification_token: Some(verification_token),
        }
    };

    let response = (
        StatusCode::CREATED,
        ApiResponse::new(response_body).into_json_response(),
    );

    Ok(response.into_response())
}