use rustc_feature::AttributeType;

use super::prelude::*;

pub(crate) struct CrateNameParser;

impl<S: Stage> SingleAttributeParser<S> for CrateNameParser {
    const PATH: &[Symbol] = &[sym::crate_name];
    const ATTRIBUTE_ORDER: AttributeOrder = AttributeOrder::KeepOutermost;
    const ON_DUPLICATE: OnDuplicate<S> = OnDuplicate::WarnButFutureError;
    const TEMPLATE: AttributeTemplate = template!(NameValueStr: "name");
    const TYPE: AttributeType = AttributeType::CrateLevel;

    // FIXME: crate name is allowed on all targets and ignored,
    //        even though it should only be valid on crates of course
    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(ALL_TARGETS);

    fn convert(cx: &mut AcceptContext<'_, '_, S>, args: &ArgParser<'_>) -> Option<AttributeKind> {
        let ArgParser::NameValue(n) = args else {
            cx.expected_name_value(cx.attr_span, None);
            return None;
        };

        let Some(name) = n.value_as_str() else {
            cx.expected_string_literal(n.value_span, Some(n.value_as_lit()));
            return None;
        };

        Some(AttributeKind::CrateName {
            name,
            name_span: n.value_span,
            attr_span: cx.attr_span,
            style: cx.attr_style,
        })
    }
}