// SPDX-FileCopyrightText: 2024 Aravinth Manivannan <realaravinth@batsense.net>
//
// SPDX-License-Identifier: AGPL-3.0-or-later

use async_trait::async_trait;
use cqrs_es::persist::GenericQuery;
use cqrs_es::persist::{PersistenceError, ViewContext, ViewRepository};
use cqrs_es::{EventEnvelope, Query, View};
use serde::{Deserialize, Serialize};
use uuid::Uuid;

use super::errors::*;
use super::DBOutPostgresAdapter;
use crate::identity::application::services::events::UserEvent;
use crate::identity::domain::aggregate::User;
use crate::utils::parse_aggregate_id::parse_aggregate_id;

pub const NEW_USER_NON_UUID: &str = "new_user_non_uuid-asdfa";

// The view for a User query, for a standard http application this should
// be designed to reflect the response dto that will be returned to a user.
#[derive(Debug, Default, Serialize, Deserialize)]
pub struct UserView {
    first_name: String,
    last_name: String,
    user_id: Uuid,
    email: String,
    hashed_password: String,
    is_admin: bool,
    is_verified: bool,
    deleted: bool,
}

// This updates the view with events as they are committed.
// The logic should be minimal here, e.g., don't calculate the account balance,
// design the events to carry the balance information instead.
impl View<User> for UserView {
    fn update(&mut self, event: &EventEnvelope<User>) {
        match &event.payload {
            UserEvent::UserRegistered(val) => {
                self.email = val.email().into();
                self.hashed_password = val.hashed_password().into();
                self.is_admin = val.is_admin().to_owned();
                self.is_verified = val.is_verified().to_owned();
                self.deleted = false;
                self.first_name = val.first_name().into();
                self.last_name = val.last_name().into();
                self.user_id = *val.user_id();
            }
            UserEvent::UserDeleted => self.deleted = true,
            UserEvent::Loggedin(_) => (),
            UserEvent::PasswordUpdated(_) => (),
            UserEvent::EmailUpdated(val) => {
                self.email = val.new_email().into();
            }
            UserEvent::UserVerified => {
                self.is_verified = true;
            }
            UserEvent::UserPromotedToAdmin(_) => {
                self.is_admin = true;
            }
            UserEvent::VerificationEmailResent => (),
        }
    }
}

#[async_trait]
impl ViewRepository<UserView, User> for DBOutPostgresAdapter {
    async fn load(&self, user_id: &str) -> Result<Option<UserView>, PersistenceError> {
        let user_id = match parse_aggregate_id(user_id, NEW_USER_NON_UUID)? {
            Some((val, _)) => return Ok(Some(val)),
            None => Uuid::parse_str(user_id).unwrap(),
        };

        let res = sqlx::query_as!(
            UserView,
            "SELECT 
                first_name, last_name, user_id, email, hashed_password, is_admin, is_verified, deleted
             FROM
                user_query
            WHERE
                user_id = $1;",
            user_id
        )
        .fetch_one(&self.pool)
        .await
        .map_err(PostgresAggregateError::from)?;
        Ok(Some(res))
    }

    async fn load_with_context(
        &self,
        user_id: &str,
    ) -> Result<Option<(UserView, ViewContext)>, PersistenceError> {
        let user_id = match parse_aggregate_id(user_id, NEW_USER_NON_UUID)? {
            Some(val) => return Ok(Some(val)),
            None => Uuid::parse_str(user_id).unwrap(),
        };

        let res = sqlx::query_as!(
            UserView,
            "SELECT 
                first_name, last_name, user_id, email, hashed_password, is_admin, is_verified, deleted
             FROM
                user_query
            WHERE
                user_id = $1;",
            user_id
        )
        .fetch_one(&self.pool)
        .await
        .map_err(PostgresAggregateError::from)?;

        struct Context {
            version: i64,
            user_id: String,
        }

        let ctx = sqlx::query_as!(
            Context,
            "SELECT 
                user_id, version
             FROM
                user_query
            WHERE
                user_id = $1;",
            user_id
        )
        .fetch_one(&self.pool)
        .await
        .map_err(PostgresAggregateError::from)?;

        let view_context = ViewContext::new(ctx.user_id.to_string(), ctx.version);
        Ok(Some((res, view_context)))
    }

    async fn update_view(
        &self,
        view: UserView,
        context: ViewContext,
    ) -> Result<(), PersistenceError> {
        match context.version {
            0 => {
                let version = context.version + 1;
                sqlx::query!(
                    "INSERT INTO user_query (
                        version, first_name, last_name, email,
                        hashed_password, is_admin, is_verified, deleted, user_id
                    ) VALUES (
                        $1, $2, $3, $4, $5, $6, $7, $8, $9
                    );",
                    version,
                    view.first_name,
                    view.last_name,
                    view.email,
                    view.hashed_password,
                    view.is_admin,
                    view.is_verified,
                    view.deleted,
                    view.user_id,
                )
                .execute(&self.pool)
                .await
                .map_err(PostgresAggregateError::from)?;
            }
            _ => {
                let version = context.version + 1;
                sqlx::query!(
                    "UPDATE
                        user_query
                    SET
                        user_id = $1, version = $2, first_name = $3, email = $4,
                        hashed_password = $5, is_admin = $6, is_verified = $7, deleted = $8,
                        last_name=$9;",
                    view.user_id,
                    version,
                    view.first_name,
                    view.email,
                    view.hashed_password,
                    view.is_admin,
                    view.is_verified,
                    view.deleted,
                    view.last_name,
                )
                .execute(&self.pool)
                .await
                .map_err(PostgresAggregateError::from)?;
            }
        }

        Ok(())
    }
}

pub struct SimpleLoggingQuery {}

// Our simplest query, this is great for debugging but absolutely useless in production.
// This query just pretty prints the events as they are processed.
#[async_trait]
impl Query<User> for SimpleLoggingQuery {
    async fn dispatch(&self, aggregate_id: &str, events: &[EventEnvelope<User>]) {
        for event in events {
            let payload = serde_json::to_string_pretty(&event.payload).unwrap();
            println!("{}-{}\n{}", aggregate_id, event.sequence, payload);
        }
    }
}

// Our second query, this one will be handled with Postgres `GenericQuery`
// which will serialize and persist our view after it is updated. It also
// provides a `load` method to deserialize the view on request.
pub type UserQuery = GenericQuery<DBOutPostgresAdapter, UserView, User>;