// Copyright (C) 2017 Jonathan Müller <jonathanmueller.dev@gmail.com>
// This file is subject to the license terms in the LICENSE file
// found in the top-level directory of this distribution.

#include "parse_functions.hpp"

#include <cppast/cpp_namespace.hpp>
#include <type_safe/deferred_construction.hpp>

#include "libclang_visitor.hpp"

using namespace cppast;

namespace
{
    cpp_namespace::builder make_ns_builder(const detail::parse_context& context,
                                           const CXCursor&              cur)
    {
        detail::cxtokenizer    tokenizer(context.tu, context.file, cur);
        detail::cxtoken_stream stream(tokenizer, cur);
        // [inline] namespace [<attribute>] <identifier> {

        auto is_inline = false;
        if (skip_if(stream, "inline"))
            is_inline = true;

        skip(stream, "namespace");
        skip_attribute(stream);

        // <identifier> {
        // or when anonymous: {
        if (detail::skip_if(stream, "{"))
            return cpp_namespace::builder("", is_inline);

        auto& name = stream.get().value();
        skip_attribute(stream);
        skip(stream, "{");
        return cpp_namespace::builder(name.c_str(), is_inline);
    }
}

std::unique_ptr<cpp_entity> detail::parse_cpp_namespace(const detail::parse_context& context,
                                                        const CXCursor&              cur)
{
    DEBUG_ASSERT(cur.kind == CXCursor_Namespace, detail::assert_handler{});

    auto builder = make_ns_builder(context, cur);
    context.comments.match(builder.get(), cur);
    detail::visit_children(cur, [&](const CXCursor& cur) {
        auto entity = parse_entity(context, cur);
        if (entity)
            builder.add_child(std::move(entity));
    });
    return builder.finish(*context.idx, get_entity_id(cur));
}

namespace
{
    cpp_entity_id parse_ns_target_cursor(const CXCursor& cur)
    {
        cpp_entity_id result("");
        detail::visit_children(cur,
                               [&](const CXCursor& child) {
                                   auto referenced = clang_getCursorReferenced(child);
                                   auto kind       = clang_getCursorKind(referenced);
                                   if (kind == CXCursor_Namespace)
                                       result = detail::get_entity_id(referenced);
                                   else if (kind == CXCursor_NamespaceAlias)
                                       // get target of namespace alias instead
                                       result = parse_ns_target_cursor(referenced);
                                   else
                                       DEBUG_UNREACHABLE(detail::parse_error_handler{}, cur,
                                                         "unexpected target for namespace "
                                                         "alias/using directive");
                               },
                               true);
        return result;
    }
}

std::unique_ptr<cpp_entity> detail::parse_cpp_namespace_alias(const detail::parse_context& context,
                                                              const CXCursor&              cur)
{
    DEBUG_ASSERT(cur.kind == CXCursor_NamespaceAlias, detail::assert_handler{});

    detail::cxtokenizer    tokenizer(context.tu, context.file, cur);
    detail::cxtoken_stream stream(tokenizer, cur);

    // namespace <identifier> = <nested identifier>;
    detail::skip(stream, "namespace");
    auto name = stream.get().c_str();
    detail::skip(stream, "=");

    // <nested identifier>;
    std::string target_name;
    while (!stream.done() && !detail::skip_if(stream, ";"))
        target_name += stream.get().c_str();

    auto target = cpp_namespace_ref(parse_ns_target_cursor(cur), std::move(target_name));
    auto result = cpp_namespace_alias::build(*context.idx, get_entity_id(cur), std::move(name),
                                             std::move(target));
    context.comments.match(*result, cur);
    return std::move(result);
}

std::unique_ptr<cpp_entity> detail::parse_cpp_using_directive(const detail::parse_context& context,
                                                              const CXCursor&              cur)
{
    DEBUG_ASSERT(cur.kind == CXCursor_UsingDirective, detail::assert_handler{});

    detail::cxtokenizer    tokenizer(context.tu, context.file, cur);
    detail::cxtoken_stream stream(tokenizer, cur);

    // using namespace <nested identifier>;
    detail::skip(stream, "using");
    detail::skip(stream, "namespace");

    // <nested identifier>;
    std::string target_name;
    while (!stream.done() && !detail::skip_if(stream, ";"))
        target_name += stream.get().c_str();

    auto target = cpp_namespace_ref(parse_ns_target_cursor(cur), std::move(target_name));
    auto result = cpp_using_directive::build(target);
    context.comments.match(*result, cur);
    return std::move(result);
}

namespace
{
    cpp_entity_ref parse_entity_target_cursor(const CXCursor& cur, std::string name)
    {
        type_safe::deferred_construction<cpp_entity_ref> result;
        detail::visit_children(cur,
                               [&](const CXCursor& child) {
                                   if (result)
                                       return;

                                   switch (clang_getCursorKind(child))
                                   {
                                   case CXCursor_TypeRef:
                                   case CXCursor_TemplateRef:
                                   case CXCursor_MemberRef:
                                   case CXCursor_VariableRef:
                                   case CXCursor_DeclRefExpr:
                                   {
                                       auto referenced = clang_getCursorReferenced(child);
                                       result = cpp_entity_ref(detail::get_entity_id(referenced),
                                                               std::move(name));
                                       break;
                                   }

                                   case CXCursor_OverloadedDeclRef:
                                   {
                                       auto size = clang_getNumOverloadedDecls(child);
                                       DEBUG_ASSERT(size >= 1u, detail::parse_error_handler{}, cur,
                                                    "no target for using declaration");
                                       std::vector<cpp_entity_id> ids;
                                       for (auto i = 0u; i != size; ++i)
                                           ids.push_back(detail::get_entity_id(
                                               clang_getOverloadedDecl(child, i)));
                                       result = cpp_entity_ref(std::move(ids), std::move(name));
                                       break;
                                   }

                                   case CXCursor_NamespaceRef:
                                       break; // wait for children

                                   default:
                                       DEBUG_UNREACHABLE(detail::parse_error_handler{}, cur,
                                                         "unexpected target for using declaration");
                                   }

                               },
                               true);
        return result.value();
    }
}

std::unique_ptr<cpp_entity> detail::parse_cpp_using_declaration(
    const detail::parse_context& context, const CXCursor& cur)
{
    DEBUG_ASSERT(cur.kind == CXCursor_UsingDeclaration, detail::assert_handler{});

    detail::cxtokenizer    tokenizer(context.tu, context.file, cur);
    detail::cxtoken_stream stream(tokenizer, cur);

    // using <nested identifier>;
    detail::skip(stream, "using");

    // <nested identifier>;
    std::string target_name;
    while (!stream.done() && !detail::skip_if(stream, ";"))
        target_name += stream.get().c_str();

    auto target = parse_entity_target_cursor(cur, std::move(target_name));
    auto result = cpp_using_declaration::build(std::move(target));
    context.comments.match(*result, cur);
    return std::move(result);
}