use hir::{DefWithBody, HasSource, ModuleSource};
use ra_db::{FileId, SourceDatabase};
use ra_syntax::{AstNode, TextRange};

use crate::{
    db::RootDatabase,
    name_kind::{Declaration, NameKind},
};

pub struct SearchScope {
    pub scope: Vec<(FileId, Option<TextRange>)>,
}

impl Declaration {
    pub fn scope(self, db: &RootDatabase) -> Option<SearchScope> {
        let module_src = self.container.definition_source(db);
        let file_id = module_src.file_id.original_file(db);

        if let NameKind::Pat((def, _)) = self.item {
            let range = match def {
                DefWithBody::Function(f) => f.source(db).ast.syntax().text_range(),
                DefWithBody::Const(c) => c.source(db).ast.syntax().text_range(),
                DefWithBody::Static(s) => s.source(db).ast.syntax().text_range(),
            };
            return Some(SearchScope { scope: vec![(file_id, Some(range))] });
        }

        if let Some(vis) = self.visibility {
            let source_root_id = db.file_source_root(file_id);
            let source_root = db.source_root(source_root_id);
            let mut files = source_root.walk().map(|id| (id.into(), None)).collect::<Vec<_>>();

            if vis.syntax().text() == "pub(crate)" {
                return Some(SearchScope { scope: files });
            }
            if vis.syntax().text() == "pub" {
                let krate = self.container.krate(db).unwrap();
                let crate_graph = db.crate_graph();

                for crate_id in crate_graph.iter() {
                    let mut crate_deps = crate_graph.dependencies(crate_id);

                    if crate_deps.any(|dep| dep.crate_id() == krate.crate_id()) {
                        let root_file = crate_graph.crate_root(crate_id);
                        let source_root_id = db.file_source_root(root_file);
                        let source_root = db.source_root(source_root_id);
                        files.extend(source_root.walk().map(|id| (id.into(), None)));
                    }
                }

                return Some(SearchScope { scope: files });
            }
            // FIXME: extend to "pub(super)" and "pub(in path)" cases,
            // then remove `Option`
            return None;
        }

        let range = match module_src.ast {
            ModuleSource::Module(m) => Some(m.syntax().text_range()),
            ModuleSource::SourceFile(_) => None,
        };
        Some(SearchScope { scope: vec![(file_id, range)] })
    }
}