use crate::structs::PrivateMessageView;
use diesel::{
  debug_query,
  pg::Pg,
  result::Error,
  BoolExpressionMethods,
  ExpressionMethods,
  JoinOnDsl,
  QueryDsl,
};
use diesel_async::RunQueryDsl;
use lemmy_db_schema::{
  newtypes::{PersonId, PrivateMessageId},
  schema::{person, private_message},
  source::{
    person::{Person, PersonSafe},
    private_message::PrivateMessage,
  },
  traits::{ToSafe, ViewToVec},
  utils::{get_conn, limit_and_offset, DbPool},
};
use tracing::debug;
use typed_builder::TypedBuilder;

type PrivateMessageViewTuple = (PrivateMessage, PersonSafe, PersonSafe);

impl PrivateMessageView {
  pub async fn read(pool: &DbPool, private_message_id: PrivateMessageId) -> Result<Self, Error> {
    let conn = &mut get_conn(pool).await?;
    let person_alias_1 = diesel::alias!(person as person1);

    let (private_message, creator, recipient) = private_message::table
      .find(private_message_id)
      .inner_join(person::table.on(private_message::creator_id.eq(person::id)))
      .inner_join(
        person_alias_1.on(private_message::recipient_id.eq(person_alias_1.field(person::id))),
      )
      .order_by(private_message::published.desc())
      .select((
        private_message::all_columns,
        Person::safe_columns_tuple(),
        person_alias_1.fields(Person::safe_columns_tuple()),
      ))
      .first::<PrivateMessageViewTuple>(conn)
      .await?;

    Ok(PrivateMessageView {
      private_message,
      creator,
      recipient,
    })
  }

  /// Gets the number of unread messages
  pub async fn get_unread_messages(pool: &DbPool, my_person_id: PersonId) -> Result<i64, Error> {
    use diesel::dsl::count;
    let conn = &mut get_conn(pool).await?;
    private_message::table
      .filter(private_message::read.eq(false))
      .filter(private_message::recipient_id.eq(my_person_id))
      .filter(private_message::deleted.eq(false))
      .select(count(private_message::id))
      .first::<i64>(conn)
      .await
  }
}

#[derive(TypedBuilder)]
#[builder(field_defaults(default))]
pub struct PrivateMessageQuery<'a> {
  #[builder(!default)]
  pool: &'a DbPool,
  #[builder(!default)]
  recipient_id: PersonId,
  unread_only: Option<bool>,
  page: Option<i64>,
  limit: Option<i64>,
}

impl<'a> PrivateMessageQuery<'a> {
  pub async fn list(self) -> Result<Vec<PrivateMessageView>, Error> {
    let conn = &mut get_conn(self.pool).await?;
    let person_alias_1 = diesel::alias!(person as person1);

    let mut query = private_message::table
      .inner_join(person::table.on(private_message::creator_id.eq(person::id)))
      .inner_join(
        person_alias_1.on(private_message::recipient_id.eq(person_alias_1.field(person::id))),
      )
      .select((
        private_message::all_columns,
        Person::safe_columns_tuple(),
        person_alias_1.fields(Person::safe_columns_tuple()),
      ))
      .into_boxed();

    // If its unread, I only want the ones to me
    if self.unread_only.unwrap_or(false) {
      query = query
        .filter(private_message::read.eq(false))
        .filter(private_message::recipient_id.eq(self.recipient_id));
    }
    // Otherwise, I want the ALL view to show both sent and received
    else {
      query = query.filter(
        private_message::recipient_id
          .eq(self.recipient_id)
          .or(private_message::creator_id.eq(self.recipient_id)),
      )
    }

    let (limit, offset) = limit_and_offset(self.page, self.limit)?;

    query = query
      .filter(private_message::deleted.eq(false))
      .limit(limit)
      .offset(offset)
      .order_by(private_message::published.desc());

    debug!(
      "Private Message View Query: {:?}",
      debug_query::<Pg, _>(&query)
    );

    let res = query.load::<PrivateMessageViewTuple>(conn).await?;

    Ok(PrivateMessageView::from_tuple_to_vec(res))
  }
}

impl ViewToVec for PrivateMessageView {
  type DbTuple = PrivateMessageViewTuple;
  fn from_tuple_to_vec(items: Vec<Self::DbTuple>) -> Vec<Self> {
    items
      .into_iter()
      .map(|a| Self {
        private_message: a.0,
        creator: a.1,
        recipient: a.2,
      })
      .collect::<Vec<Self>>()
  }
}