src/grammars.hpp

/*
 * Copyright (C) 2018 CESNET, https://photonics.cesnet.cz/
 * Copyright (C) 2018 FIT CVUT, https://fit.cvut.cz/
 *
 * Written by Václav Kubernát <kubervac@fit.cvut.cz>
 *
*/

#pragma once

#include <boost/spirit/home/x3.hpp>
#include "ast_commands.hpp"
#include "ast_handlers.hpp"
#include "common_parsers.hpp"
#include "leaf_data.hpp"
#include "path_parser.hpp"

/**
 * Returns a parser that generates suggestions based on a Completion set.
 * Usage:
 * const auto suggestSomeStuff = staticSuggestions({"some", "stuff", "yay"});
 *
 * You can use this as a standard parser in a Spirit grammar.
 */
auto staticSuggestions(const std::initializer_list<std::string>& strings)
{
    std::set<Completion> completions;
    std::transform(begin(strings), end(strings), std::inserter(completions, completions.end()),
            [](const auto s) { return Completion{s, " "}; });
    return as<x3::unused_type>[x3::eps[([completions](auto& ctx) {
        auto& parserContext = x3::get<parser_context_tag>(ctx);
        parserContext.m_suggestions = completions;
        parserContext.m_completionIterator = _where(ctx).begin();
    })]];
}

#if BOOST_VERSION <= 107700
namespace boost::spirit::x3::traits {
    // Backport https://github.com/boostorg/spirit/pull/702
    // with instructions from https://github.com/boostorg/spirit/issues/701#issuecomment-946743099
    template <typename... Types, typename T>
    struct variant_find_substitute<boost::variant<Types...>, T>
    {
        using variant_type = boost::variant<Types...>;

        typedef typename variant_type::types types;
        typedef typename mpl::end<types>::type end;

        typedef typename mpl::find<types, T>::type iter_1;

        typedef typename
            mpl::eval_if<
            is_same<iter_1, end>,
            mpl::find_if<types, traits::is_substitute<T, mpl::_1> >,
            mpl::identity<iter_1>
                >::type
                iter;

        typedef typename
            mpl::eval_if<
            is_same<iter, end>,
            mpl::identity<T>,
            mpl::deref<iter>
                >::type
                type;
    };
}
#endif


#if __clang__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Woverloaded-shift-op-parentheses"
#endif

namespace ascii = boost::spirit::x3::ascii;

struct ls_options_table : x3::symbols<LsOption> {
    ls_options_table()
    {
    add
        ("--recursive", LsOption::Recursive);
    }
} const ls_options;

auto const ls = x3::rule<ls_class, ls_>{"ls"} =
    ls_::name >> *(space_separator >> ls_options) >> -(space_separator > (anyPath | (module >> "*")));

auto const cd = x3::rule<cd_class, cd_>{"cd"} =
    cd_::name >> space_separator > cdPath;

#if BOOST_VERSION <= 107700
auto const create = x3::rule<create_class, create_>{"create"} =
    create_::name >> space_separator >
    (x3::eps >> presenceContainerPath |
     x3::eps >> listInstancePath |
     x3::eps >> leafListElementPath);

auto const delete_rule = x3::rule<delete_class, delete_>{"delete_rule"} =
    delete_::name >> space_separator >
    (x3::eps >> presenceContainerPath |
     x3::eps >> listInstancePath |
     x3::eps >> leafListElementPath |
     x3::eps >> writableLeafPath);
#else
auto const create = x3::rule<create_class, create_>{"create"} =
    create_::name >> space_separator > (presenceContainerPath | listInstancePath | leafListElementPath);

auto const delete_rule = x3::rule<delete_class, delete_>{"delete_rule"} =
    delete_::name >> space_separator > (presenceContainerPath | listInstancePath | leafListElementPath | writableLeafPath);
#endif

const auto dsTargetSuggestions = staticSuggestions({"running", "startup", "operational"});

struct ds_target_table : x3::symbols<DatastoreTarget> {
    ds_target_table()
    {
        add
            ("operational", DatastoreTarget::Operational)
            ("startup", DatastoreTarget::Startup)
            ("running", DatastoreTarget::Running);
    }
} const ds_target_table;

auto const get = x3::rule<get_class, get_>{"get"} =
    get_::name
    >> -(space_separator >> "-" > staticSuggestions({"-datastore"}) > "-datastore" > space_separator > dsTargetSuggestions > ds_target_table)
    >> -(space_separator > getPath);

auto const set = x3::rule<set_class, set_>{"set"} =
    set_::name >> space_separator > writableLeafPath > space_separator > leaf_data;

auto const commit = x3::rule<commit_class, commit_>{"commit"} =
    commit_::name >> x3::attr(commit_());

auto const discard = x3::rule<discard_class, discard_>{"discard"} =
    discard_::name >> x3::attr(discard_());

struct command_names_table : x3::symbols<decltype(help_::m_cmd)> {
    command_names_table()
    {
        boost::mpl::for_each<CommandTypes, boost::type<boost::mpl::_>>([this](auto cmd) {
            add(commandNamesVisitor(cmd), decltype(help_::m_cmd)(cmd));
        });
    }
} const command_names;

auto const createCommandSuggestions = x3::rule<createCommandSuggestions_class, x3::unused_type>{"createCommandSuggestions"} =
    x3::eps;

auto const help = x3::rule<help_class, help_>{"help"} =
    help_::name > createCommandSuggestions >> -command_names;

struct datastore_symbol_table : x3::symbols<Datastore> {
    datastore_symbol_table()
    {
        add
            ("running", Datastore::Running)
            ("startup", Datastore::Startup);
    }
} const datastore;

const auto copy_source = x3::rule<class source, Datastore>{"source datastore"} = datastore;
const auto copy_destination = x3::rule<class source, Datastore>{"destination datastore"} = datastore;

const auto datastoreSuggestions = staticSuggestions({"running", "startup"});

struct copy_args : x3::parser<copy_args> {
    using attribute_type = copy_;
    template <typename It, typename Ctx, typename RCtx>
    bool parse(It& begin, It end, Ctx const& ctx, RCtx& rctx, copy_& attr) const
    {
        auto& parserContext = x3::get<parser_context_tag>(ctx);
        auto iterBeforeDestination = begin;
        auto save_iter = x3::eps[([&iterBeforeDestination](auto& ctx) { iterBeforeDestination = _where(ctx).begin(); })];
        auto grammar = datastoreSuggestions > copy_source > space_separator > datastoreSuggestions > save_iter > copy_destination;

        try {
            grammar.parse(begin, end, ctx, rctx, attr);
        } catch (x3::expectation_failure<It>& ex) {
            using namespace std::string_literals;
            parserContext.m_errorMsg = "Expected "s + ex.which() + " here:";
            throw;
        }

        if (attr.m_source == attr.m_destination) {
            begin = iterBeforeDestination; // Restoring the iterator here makes the error caret point to the second datastore
            parserContext.m_errorMsg = "Source datastore and destination datastore can't be the same.";
            return false;
        }

        return true;
    }
} const copy_args;

auto const copy = x3::rule<copy_class, copy_>{"copy"} =
    copy_::name > space_separator > copy_args;

auto const describe = x3::rule<describe_class, describe_>{"describe"} =
    describe_::name >> space_separator > anyPath;

struct move_mode_table : x3::symbols<MoveMode> {
    move_mode_table()
    {
        add
            ("after", MoveMode::After)
            ("before", MoveMode::Before)
            ("begin", MoveMode::Begin)
            ("end", MoveMode::End);
    }
} const move_mode_table;

struct move_absolute_table : x3::symbols<yang::move::Absolute> {
    move_absolute_table()
    {
        add
            ("begin", yang::move::Absolute::Begin)
            ("end", yang::move::Absolute::End);
    }
} const move_absolute_table;

struct move_relative_table : x3::symbols<yang::move::Relative::Position> {
    move_relative_table()
    {
        add
            ("before", yang::move::Relative::Position::Before)
            ("after", yang::move::Relative::Position::After);
    }
} const move_relative_table;

struct move_args : x3::parser<move_args> {
    using attribute_type = move_;
    template <typename It, typename Ctx, typename RCtx>
    bool parse(It& begin, It end, Ctx const& ctx, RCtx& rctx, move_& attr) const
    {
        ParserContext& parserContext = x3::get<parser_context_tag>(ctx);
        dataPath_ movePath;
#if BOOST_VERSION <= 107700
        auto movePathGrammar = x3::eps >> listInstancePath | x3::eps >> leafListElementPath;
#else
        auto movePathGrammar = listInstancePath | leafListElementPath;
#endif
        auto res = movePathGrammar.parse(begin, end, ctx, rctx, attr.m_source);
        if (!res) {
            parserContext.m_errorMsg = "Expected source path here:";
            return false;
        }

        // Try absolute move first.
        res = (space_separator >> move_absolute_table).parse(begin, end, ctx, rctx, attr.m_destination);
        if (res) {
            // Absolute move parsing succeeded, we don't need to parse anything else.
            return true;
        }

        // If absolute move didn't succeed, try relative.
        attr.m_destination = yang::move::Relative{};
        res = (space_separator >> move_relative_table).parse(begin, end, ctx, rctx, std::get<yang::move::Relative>(attr.m_destination).m_position);

        if (!res) {
            parserContext.m_errorMsg = "Expected a move position (begin, end, before, after) here:";
            return false;
        }

        if (std::holds_alternative<leafListElement_>(attr.m_source.m_nodes.back().m_suffix)) {
            leaf_data_ value;
            res = (space_separator >> leaf_data).parse(begin, end, ctx, rctx, value);
            if (res) {
                std::get<yang::move::Relative>(attr.m_destination).m_path = {{".", value}};
            }
        } else {
            ListInstance listInstance;
            // The source list instance will be stored inside the parser context path.
            // The source list instance will be full data path (with keys included).
            // However, m_tmpListPath is supposed to store a path with a list without the keys.
            // So, I pop the last listElement_ (which has the keys) and put in a list_ (which doesn't have the keys).
            // Example: /mod:cont/protocols[name='ftp'] gets turned into /mod:cont/protocols
            parserContext.m_tmpListPath = parserContext.currentDataPath();
            parserContext.m_tmpListPath.m_nodes.pop_back();
            auto list = list_{std::get<listElement_>(attr.m_source.m_nodes.back().m_suffix).m_name};
            parserContext.m_tmpListPath.m_nodes.emplace_back(attr.m_source.m_nodes.back().m_prefix, list);

            res = (space_separator >> listSuffix).parse(begin, end, ctx, rctx, listInstance);
            if (res) {
                std::get<yang::move::Relative>(attr.m_destination).m_path = listInstance;
            }
        }

        if (!res) {
            parserContext.m_errorMsg = "Expected a destination here:";
        }

        return res;
    }
} const move_args;

auto const move = x3::rule<move_class, move_>{"move"} =
    move_::name >> space_separator >> move_args;

struct format_table : x3::symbols<DataFormat> {
    format_table()
    {
        add
            ("xml", DataFormat::Xml)
            ("json", DataFormat::Json);
    }
} const format_table;

struct dump_args : x3::parser<dump_args> {
    using attribute_type = dump_;
    template <typename It, typename Ctx, typename RCtx>
    bool parse(It& begin, It end, Ctx const& ctx, RCtx& rctx, dump_& attr) const
    {
        ParserContext& parserContext = x3::get<parser_context_tag>(ctx);
        parserContext.m_suggestions = {{"xml"}, {"json"}};
        parserContext.m_completionIterator = begin;
        auto res = format_table.parse(begin, end, ctx, rctx, attr);
        if (!res) {
            parserContext.m_errorMsg = "Expected a data format (xml, json) here:";
        }
        return res;
    }
} const dump_args;

auto const prepare = x3::rule<prepare_class, prepare_>{"prepare"} =
    prepare_::name > space_separator > as<dataPath_>[RpcActionPath<AllowInput::Yes>{}];

auto const exec = x3::rule<exec_class, exec_>{"exec"} =
    exec_::name > -(space_separator > -as<dataPath_>[RpcActionPath<AllowInput::No>{}]);

auto const switch_rule = x3::rule<switch_class, switch_>{"switch"} =
    switch_::name > space_separator > dsTargetSuggestions > ds_target_table;

auto const cancel = x3::rule<cancel_class, cancel_>{"cancel"} =
    cancel_::name >> x3::attr(cancel_{});

auto const dump = x3::rule<dump_class, dump_>{"dump"} =
    dump_::name > space_separator >> dump_args;

auto const quit = x3::rule<quit_class, quit_>{"quit"} =
    quit_::name >> x3::attr(quit_{});

auto const command = x3::rule<command_class, command_>{"command"} =
#if BOOST_VERSION <= 107800
    x3::eps >>
#endif
    -space_separator >> createCommandSuggestions >> x3::expect[cd | copy | create | delete_rule | set | commit | get | ls | discard | describe | help | move | dump | prepare | exec | cancel | switch_rule | quit] >> -space_separator;

#if __clang__
#pragma GCC diagnostic pop
#endif