//! HIR for trait definitions.

use std::sync::Arc;

use ra_syntax::ast::{self, NameOwner};

use crate::{Function, Const, TypeAlias, Name, DefDatabase, Trait, ids::LocationCtx, name::AsName};

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct TraitData {
    name: Option<Name>,
    items: Vec<TraitItem>,
}

impl TraitData {
    pub(crate) fn trait_data_query(db: &impl DefDatabase, tr: Trait) -> Arc<TraitData> {
        let (file_id, node) = tr.source(db);
        let name = node.name().map(|n| n.as_name());
        let module = tr.module(db);
        let ctx = LocationCtx::new(db, module, file_id);
        let items = if let Some(item_list) = node.item_list() {
            item_list
                .impl_items()
                .map(|item_node| match item_node.kind() {
                    ast::ImplItemKind::FnDef(it) => Function { id: ctx.to_def(it) }.into(),
                    ast::ImplItemKind::ConstDef(it) => Const { id: ctx.to_def(it) }.into(),
                    ast::ImplItemKind::TypeAliasDef(it) => TypeAlias { id: ctx.to_def(it) }.into(),
                })
                .collect()
        } else {
            Vec::new()
        };
        Arc::new(TraitData { name, items })
    }

    pub(crate) fn name(&self) -> &Option<Name> {
        &self.name
    }

    pub(crate) fn items(&self) -> &[TraitItem] {
        &self.items
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum TraitItem {
    Function(Function),
    Const(Const),
    TypeAlias(TypeAlias),
    // Existential
}
impl_froms!(TraitItem: Function, Const, TypeAlias);