keelson-gen 0.1.1

// @generated by keelson-gen. DO NOT EDIT.
// Regenerate from the schema instead; hand-written code (hooks included)
// belongs outside this directory.

/// The model marker `threads::table()` hangs off.
#[derive(Debug, Clone, Copy)]
pub struct Threads;
/// One row of `threads`.
#[derive(Debug, Clone, PartialEq)]
pub struct Thread {
    pub id: i32,
    pub title: String,
    pub first_message_id: Option<i32>,
    /// Relations, filled by `preload`/`then_load` mods; empty otherwise.
    pub rel: Rel,
}
/// `threads`' relations.
#[derive(Debug, Clone, PartialEq, Default)]
pub struct Rel {
    /// Belongs-to `messages`, via `threads.first_message_id`.
    pub first_message: Option<Box<super::messages::Message>>,
    /// Has-many `messages`, via `messages.thread_id`.
    pub messages: Vec<super::messages::Message>,
}
impl keelson_exec::FromRow for Thread {
    fn from_row(row: &mut keelson_exec::Row) -> Result<Self, keelson_exec::ExecError> {
        Ok(Thread {
            id: row.take("id")?,
            title: row.take("title")?,
            first_message_id: row.take("first_message_id")?,
            rel: Rel::default(),
        })
    }
}
/// The three-state setter: unset fields stay out of the statement.
#[derive(Debug, Clone, Default)]
pub struct Setter {
    pub id: keelson_models::Set<i32>,
    pub title: keelson_models::Set<String>,
    pub first_message_id: keelson_models::Set<i32>,
}
/// The entry point: `threads::table().query(…)` / `.insert(…)` / ….
pub fn table() -> keelson_models::ModelTable<Threads> {
    keelson_models::ModelTable::new()
}
pub fn id() -> keelson_models::Column<i32> {
    keelson_models::Column::new("threads", "id")
}
pub fn title() -> keelson_models::Column<String> {
    keelson_models::Column::new("threads", "title")
}
pub fn first_message_id() -> keelson_models::Column<i32> {
    keelson_models::Column::new("threads", "first_message_id")
}
#[allow(clippy::type_complexity)]
fn all_columns() -> (
    keelson_models::Column<i32>,
    keelson_models::Column<String>,
    keelson_models::Column<i32>,
) {
    (id(), title(), first_message_id())
}
impl keelson_models::View for Threads {
    type Row = Thread;
    type Select = keelson_psql::SelectQuery;
    fn base_select() -> Self::Select {
        keelson_psql::select((
            keelson_psql::select::columns(all_columns()),
            keelson_psql::select::from(keelson_psql::quote("threads")),
        ))
    }
}
impl keelson_models::Table for Threads {
    type Pk = i32;
    type Setter = Setter;
    type Insert = keelson_psql::InsertQuery;
    type Update = keelson_psql::UpdateQuery;
    type Delete = keelson_psql::DeleteQuery;
    fn insert_query(s: Setter) -> Self::Insert {
        let mut cols: Vec<&'static str> = Vec::new();
        let mut vals: Vec<keelson_core::expr::Expr> = Vec::new();
        s.id.push_into("id", &mut cols, &mut vals);
        s.title.push_into("title", &mut cols, &mut vals);
        s.first_message_id.push_into("first_message_id", &mut cols, &mut vals);
        let mut q = keelson_psql::insert((
            keelson_psql::insert::into(keelson_psql::quote("threads")).columns(cols),
            keelson_psql::insert::returning(all_columns()),
        ));
        if !vals.is_empty() {
            q.apply(keelson_psql::insert::values(vals));
        }
        q
    }
    fn update_query() -> Self::Update {
        keelson_psql::update(keelson_psql::update::table(keelson_psql::quote("threads")))
    }
    fn apply_setter(s: Setter, q: &mut Self::Update) {
        if let Some(v) = s.id.into_expr() {
            q.apply(keelson_psql::update::set_col("id").to(v));
        }
        if let Some(v) = s.title.into_expr() {
            q.apply(keelson_psql::update::set_col("title").to(v));
        }
        if let Some(v) = s.first_message_id.into_expr() {
            q.apply(keelson_psql::update::set_col("first_message_id").to(v));
        }
    }
    fn delete_query() -> Self::Delete {
        keelson_psql::delete(keelson_psql::delete::from(keelson_psql::quote("threads")))
    }
    fn pk(row: &Thread) -> Self::Pk {
        row.id
    }
}
/// Preload mods: the relation joins into the *same* query — no second statement, and deliberately no `.then(…)`. A level below a join has no distinct child set to key on, so a nested path is spelled with `then_load` (see `keelson_models::ThenLoad`).
pub mod preload {
    /// Same-query `LEFT JOIN` preload of the to-one `first_message`.
    pub fn first_message() -> impl keelson_core::Mod<
        keelson_models::ModelSelect<super::Threads>,
    > {
        keelson_core::mod_fn(|q: &mut keelson_models::ModelSelect<super::Threads>| {
            use keelson_psql::Chain as _;
            use keelson_psql::Mod as _;
            (
                keelson_psql::select::left_join(keelson_psql::quote("messages"))
                    .on(
                        keelson_psql::quote(("messages", "id"))
                            .eq(keelson_psql::quote(("threads", "first_message_id"))),
                    ),
                keelson_psql::select::preload_columns((
                    keelson_psql::quote(("messages", "id")).as_("first_message.id"),
                    keelson_psql::quote(("messages", "thread_id"))
                        .as_("first_message.thread_id"),
                    keelson_psql::quote(("messages", "body")).as_("first_message.body"),
                )),
            )
                .apply(q);
            q.add_mapper_mod(
                keelson_models::mapper_mod(|row, parent: &mut super::Thread| {
                    parent.rel.first_message = first_message_from_preload(row)?
                        .map(Box::new);
                    Ok(())
                }),
            );
        })
    }
    /// Decode the prefixed columns; the joined key column decides a `LEFT JOIN` miss.
    pub fn first_message_from_preload(
        row: &mut keelson_exec::Row,
    ) -> Result<Option<super::super::messages::Message>, keelson_exec::ExecError> {
        if matches!(
            row.value("first_message.id"), None | Some(keelson_psql::Value::Null)
        ) {
            return Ok(None);
        }
        Ok(
            Some(super::super::messages::Message {
                id: row.take("first_message.id")?,
                thread_id: row.take("first_message.thread_id")?,
                body: row.take("first_message.body")?,
                rel: super::super::messages::Rel::default(),
            }),
        )
    }
}
/// Then-load mods: one keyed, batched query per level of a load path — `then_load::a().then(b::then_load::c())` is two levels, two queries, checked by the compiler.
pub mod then_load {
    /// Load each row's `first_message` (to-one), one keyed query per batch of keys — `.then(…)` hangs the next level of the path off this one.
    pub fn first_message() -> keelson_models::ThenLoad<
        super::Threads,
        super::super::messages::Messages,
        i32,
    > {
        keelson_models::ThenLoad::new(
            |rows: &[super::Thread]| {
                rows.iter().filter_map(|r| r.first_message_id).collect()
            },
            |keys, q| keelson_core::Mod::apply(
                super::super::messages::id().in_(keys),
                q,
            ),
            |rows: &mut [super::Thread], related| {
                keelson_models::attach_to_one(
                    rows,
                    related,
                    |r| r.first_message_id,
                    |c| Some(c.id),
                    |r, c| {
                        r.rel.first_message = c.map(Box::new);
                    },
                );
            },
        )
    }
    /// Load each row's `messages` (to-many), one keyed query per batch of keys — `.then(…)` hangs the next level of the path off this one.
    pub fn messages() -> keelson_models::ThenLoad<
        super::Threads,
        super::super::messages::Messages,
        i32,
    > {
        keelson_models::ThenLoad::new(
            |rows: &[super::Thread]| rows.iter().map(|r| r.id).collect(),
            |keys, q| keelson_core::Mod::apply(
                super::super::messages::thread_id().in_(keys),
                q,
            ),
            |rows: &mut [super::Thread], related| {
                keelson_models::attach_to_many(
                    rows,
                    related,
                    |r| r.id,
                    |c| c.thread_id,
                    |r, cs| {
                        r.rel.messages = cs;
                    },
                );
            },
        )
    }
}