pub(crate) mod function;
pub(crate) mod module;

use std::sync::Arc;

use ra_syntax::{
    ast::{self, AstNode, FnDefNode},
    TextRange, SmolStr,
};

use crate::{
    db::SyntaxDatabase,
    descriptors::function::{resolve_local_name, FnId, FnScopes},
    descriptors::module::{ModuleId, ModuleTree, ModuleSource, nameres::{ItemMap, InputModuleItems}},
    input::SourceRootId,
    loc2id::IdDatabase,
    syntax_ptr::LocalSyntaxPtr,
    Cancelable,
};

salsa::query_group! {
    pub(crate) trait DescriptorDatabase: SyntaxDatabase + IdDatabase {
        fn fn_scopes(fn_id: FnId) -> Arc<FnScopes> {
            type FnScopesQuery;
            use fn function::imp::fn_scopes;
        }

        fn _input_module_items(source_root_id: SourceRootId, module_id: ModuleId) -> Cancelable<Arc<InputModuleItems>> {
            type InputModuleItemsQuery;
            use fn module::nameres::input_module_items;
        }
        fn _item_map(source_root_id: SourceRootId) -> Cancelable<Arc<ItemMap>> {
            type ItemMapQuery;
            use fn module::nameres::item_map;
        }
        fn _module_tree(source_root_id: SourceRootId) -> Cancelable<Arc<ModuleTree>> {
            type ModuleTreeQuery;
            use fn module::imp::module_tree;
        }
        fn _fn_syntax(fn_id: FnId) -> FnDefNode {
            type FnSyntaxQuery;
            // Don't retain syntax trees in memory
            storage volatile;
            use fn function::imp::fn_syntax;
        }
        fn _submodules(source: ModuleSource) -> Cancelable<Arc<Vec<module::imp::Submodule>>> {
            type SubmodulesQuery;
            use fn module::imp::submodules;
        }
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub(crate) struct Path {
    kind: PathKind,
    segments: Vec<SmolStr>,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) enum PathKind {
    Abs,
    Self_,
    Super,
    Crate,
}

#[derive(Debug)]
pub struct ReferenceDescriptor {
    pub range: TextRange,
    pub name: String,
}

#[derive(Debug)]
pub struct DeclarationDescriptor<'a> {
    pat: ast::BindPat<'a>,
    pub range: TextRange,
}

impl<'a> DeclarationDescriptor<'a> {
    pub fn new(pat: ast::BindPat) -> DeclarationDescriptor {
        let range = pat.syntax().range();

        DeclarationDescriptor { pat, range }
    }

    pub fn find_all_refs(&self) -> Vec<ReferenceDescriptor> {
        let name_ptr = LocalSyntaxPtr::new(self.pat.syntax());

        let fn_def = match self.pat.syntax().ancestors().find_map(ast::FnDef::cast) {
            Some(def) => def,
            None => return Default::default(),
        };

        let fn_scopes = FnScopes::new(fn_def);

        let refs: Vec<_> = fn_def
            .syntax()
            .descendants()
            .filter_map(ast::NameRef::cast)
            .filter(|name_ref| match resolve_local_name(*name_ref, &fn_scopes) {
                None => false,
                Some(entry) => entry.ptr() == name_ptr,
            })
            .map(|name_ref| ReferenceDescriptor {
                name: name_ref.syntax().text().to_string(),
                range: name_ref.syntax().range(),
            })
            .collect();

        refs
    }
}