// Copyright (C) 2017-2022 Jonathan Müller and cppast contributors
// SPDX-License-Identifier: MIT

#include "cppast/cpp_member_function.hpp"
#include <iostream>

#include <cxxopts.hpp>

#include <cppast/code_generator.hpp>         // for generate_code()
#include <cppast/cpp_type.hpp>         // for generate_code()
#include <cppast/cpp_entity_kind.hpp>        // for the cpp_entity_kind definition
#include <cppast/cpp_forward_declarable.hpp> // for is_definition()
#include <cppast/cpp_namespace.hpp>          // for cpp_namespace
#include <cppast/libclang_parser.hpp> // for libclang_parser, libclang_compile_config, cpp_entity,...
#include <cppast/visitor.hpp>         // for visit()

std::string CLASS_SUFFIX = "Ext";
std::string FUNC_SUFFIX = "Func";
std::string FUNC_VAR_PREFIX = "m_";

bool is_excluded_synopsis(const cppast::cpp_entity& e, cppast::cpp_access_specifier_kind access)
{
    // exclude privates and those marked for exclusion
    return access == cppast::cpp_private || cppast::has_attribute(e, "documentation::exclude");
}

// print help options
void print_help(const cxxopts::Options& options)
{
    std::cout << options.help({"", "compilation"}) << '\n';
}

// print error message
void print_error(const std::string& msg)
{
    std::cerr << msg << '\n';
}

std::string generate_synopsis(const cppast::cpp_entity& e)
{
    // the generator for the synopsis
    class synopsis_generator final : public cppast::code_generator
    {
    public:
        // get the resulting string
        std::string result()
        {
            return std::move(str_);
        }

    private:
        // whether or not the entity is the main entity that is being documented
        bool is_main_entity(const cppast::cpp_entity& e)
        {
            if (cppast::is_templated(e) || cppast::is_friended(e))
                // need to ask the real entity
                return is_main_entity(e.parent().value());
            else
                return &e == &this->main_entity();
        }

        // get some nicer formatting
        cppast::formatting do_get_formatting() const override
        {
            return cppast::formatting_flags::brace_nl | cppast::formatting_flags::comma_ws
                   | cppast::formatting_flags::operator_ws;
        }

        // calculate generation options
        generation_options do_get_options(const cppast::cpp_entity&         e,
                                          cppast::cpp_access_specifier_kind access) override
        {
            if (!is_main_entity(e))
                // only generation declaration for the non-documented entity
                return cppast::code_generator::declaration;
            else
                // default options
                return {};
        }

        // update indendation level
        void do_indent() override
        {
            ++indent_;
        }
        void do_unindent() override
        {
            if (indent_)
                --indent_;
        }

        // write specified tokens
        // need to change indentation for each newline
        void do_write_token_seq(cppast::string_view tokens) override
        {
            if (was_newline_)
            {
                str_ += std::string(indent_ * 2u, ' ');
                was_newline_ = false;
            }

            str_ += tokens.c_str();
        }

        // write + remember newline
        void do_write_newline() override
        {
            str_ += "\n";
            was_newline_ = true;
        }

        std::string str_;
        unsigned    indent_      = 0;
        bool        was_newline_ = false;
    } generator;
    cppast::generate_code(generator, e);
    return generator.result();
}

// trim from end (in place)
static inline void rtrim(std::string &s) {
    s.erase(std::find_if(s.rbegin(), s.rend(), [](unsigned char ch) {
        return !std::isspace(ch);
    }).base(), s.end());
}

void output_member_function_typedef(std::stringstream& out, const cppast::cpp_entity& e, std::string& current_class) {
    if (e.kind() != cppast::cpp_entity_kind::member_function_t) {
        return;
    }

    auto& mf = static_cast<const cppast::cpp_member_function_base&>(e);
    out << "typedef ";
    out << cppast::to_string(mf.return_type()) << " ";
    out << "(*"<< current_class << mf.name() << FUNC_SUFFIX << ")(const " << current_class << "*" << " self";
    int i = 0;
    for (auto& param : mf.parameters()) {
        if (i == 0) {
            // add comma if there are parameters
            out << ", ";
        }
        out << ( i ? ", " : "" );
        out << cppast::to_string(param.type()) << " " << param.name();
        i++;
    }
    out << ");\n";
}

void output_member_function(std::stringstream& out, const cppast::cpp_entity& e, std::string& prefix, std::string& base_class, std::string& current_class) {
    if (e.kind() != cppast::cpp_entity_kind::member_function_t) return;

    auto& mf = static_cast<const cppast::cpp_member_function_base&>(e);
    int j = 0;
    for (auto& param : mf.parameters()) {
        if (param.name().empty()) {
            param.set_name("param" + std::to_string(j));
        }
        j++;
    }

    std::string method_stub = generate_synopsis(e);
    rtrim(method_stub);
    method_stub.pop_back(); // get rid of semicolon

    std::string mvar_name = FUNC_VAR_PREFIX + mf.name();
    std::string func_type = current_class + mf.name() + FUNC_SUFFIX;
    std::stringstream all_params_stream;

    int i = 0;
    for (auto& param : mf.parameters()) {
        all_params_stream << ( i ? ", " : "" );
        all_params_stream << param.name();
        i++;
    }
    std::string all_params = all_params_stream.str();

    // generate class var
    out << prefix << func_type << " " << mvar_name << ";\n";
    // TODO: Generate class var accessors (Get and Set)
    // Maybe don't need to?

    bool is_override = cppast::is_overriding(mf.virtual_info());
    // generate method
    out << prefix << method_stub;
    if (method_stub.find("override") == std::string::npos || !is_override) {
        out << " override";
    }
    out << "\n";
    out << prefix << "{\n";
    out << prefix << prefix;

    std::string ret_type = cppast::to_string(mf.return_type());
    bool is_void = ret_type == "void";

    // call super
    if (!is_void) {
        out << ret_type << " res = ";
    }
    out << base_class << "::" << mf.name() << "(" << all_params << ");\n";
    out << prefix << prefix;

    out << "if (" << mvar_name << "){\n";
    out << prefix << prefix << prefix;
    out << "return ";
    if (i > 0) {
        out << mvar_name << "(this, " << all_params << ");\n";
    }
    else {
        out << mvar_name << "(this);\n";
    }
    out << prefix << prefix;
    out << "}\n"; // endif
    if (!is_void) {
        out << prefix << prefix;
        out << "else {\n";
        out << prefix << prefix << prefix;
        out << "return res;\n";
        out << prefix << prefix;
        out << "}\n";

    }

    out << prefix << "}\n";
}

// prints the AST of a file
void print_ast(std::ostream& out, const cppast::cpp_file& file)
{
    // print file name
    std::cerr << "AST for '" << file.name() << "':\n";
    out << "#include <wx/wx.h>\n#include <wx/vidmode.h>\n\n";
    std::string prefix; // the current prefix string
    std::string current_class; // the current class
    std::string base_class; // the current base class

    std::stringstream forward_decls;
    std::stringstream class_stream;

    // - Forward declare the class
    // - typedef all of the virtual methods with class as first arg
    // - declare the class with a postfix (class wxAppC: public wxApp)
    // - output variable and virtual method override
    //   check function pointer for null, then call it
    //
    cppast::visit(file,
        [](const cppast::cpp_entity& e, cppast::cpp_access_specifier_kind access) {
            // only visit non-templated class definitions
            return (!cppast::is_templated(e) &&
                    access != cppast::cpp_private &&
                    (
                     (e.kind() == cppast::cpp_entity_kind::class_t && cppast::is_definition(e)) ||
                     (e.kind() == cppast::cpp_entity_kind::member_function_t && static_cast<const cppast::cpp_member_function_base&>(e).is_virtual()) ||
                     (e.kind() == cppast::cpp_entity_kind::constructor_t) ||
                     (e.kind() == cppast::cpp_entity_kind::destructor_t && static_cast<const cppast::cpp_destructor&>(e).is_virtual()) ||
                     e.kind() == cppast::cpp_entity_kind::base_class_t
                    )
                   );
        },

        [&](const cppast::cpp_entity& e, cppast::visitor_info info) {
            if (info.event == cppast::visitor_info::container_entity_enter) {
                if (e.kind() == cppast::cpp_entity_kind::class_t) {
                    base_class = e.name();
                    current_class = e.name() + CLASS_SUFFIX;
                    forward_decls << "class " << current_class << ";\n";

                    class_stream << "class " << current_class << ": public " << base_class;
                    class_stream << "\n{\n";
                    class_stream << "public:\n";
                }
                /* else if (e.kind() == cppast::cpp_entity_kind::member_function_t) { */
                    
                /* } */
                prefix += "  ";
            }
            else if (info.event == cppast::visitor_info::container_entity_exit)
            {
                // we have visited all children of a container,
                // remove prefix
                prefix.pop_back();
                prefix.pop_back();
                if (e.kind() == cppast::cpp_entity_kind::class_t) {
                    class_stream << prefix << "};\n\n";
                }
            }
            else
            {
                if (e.kind() == cppast::cpp_entity_kind::member_function_t) {
                    auto& mf = static_cast<const cppast::cpp_member_function_base&>(e);
                    int j = 0;
                    for (auto& param : mf.parameters()) {
                        if (param.name().empty()) {
                            param.set_name("param" + std::to_string(j));
                        }
                        j++;
                    }

                    output_member_function_typedef(forward_decls, e, current_class);
                    output_member_function(class_stream, e, prefix, base_class, current_class);
                }
            }

            return true;
    });
    out << forward_decls.str() << "\n";
    out << class_stream.str();

}

// parse a file
std::unique_ptr<cppast::cpp_file> parse_file(const cppast::libclang_compile_config& config,
                                             const cppast::diagnostic_logger&       logger,
                                             const std::string& filename, bool fatal_error)
{
    // the entity index is used to resolve cross references in the AST
    // we don't need that, so it will not be needed afterwards
    cppast::cpp_entity_index idx;
    // the parser is used to parse the entity
    // there can be multiple parser implementations
    cppast::libclang_parser parser(type_safe::ref(logger));
    // parse the file
    auto file = parser.parse(idx, filename, config);
    if (fatal_error && parser.error())
        return nullptr;
    return file;
}

int main(int argc, char* argv[])
try
{
    cxxopts::Options option_list("cppast",
                                 "cppast - The commandline interface to the cppast library.\n");
    // clang-format off
    option_list.add_options()
        ("h,help", "display this help and exit")
        ("version", "display version information and exit")
        ("v,verbose", "be verbose when parsing")
        ("fatal_errors", "abort program when a parser error occurs, instead of doing error correction")
        ("file", "the file that is being parsed (last positional argument)",
         cxxopts::value<std::string>());
    option_list.add_options("compilation")
        ("database_dir", "set the directory where a 'compile_commands.json' file is located containing build information",
        cxxopts::value<std::string>())
        ("database_file", "set the file name whose configuration will be used regardless of the current file name",
        cxxopts::value<std::string>())
        ("std", "set the C++ standard (c++98, c++03, c++11, c++14, c++1z (experimental), c++17, c++2a, c++20)",
         cxxopts::value<std::string>()->default_value(cppast::to_string(cppast::cpp_standard::cpp_latest)))
        ("I,include_directory", "add directory to include search path",
         cxxopts::value<std::vector<std::string>>())
        ("D,macro_definition", "define a macro on the command line",
         cxxopts::value<std::vector<std::string>>())
        ("U,macro_undefinition", "undefine a macro on the command line",
         cxxopts::value<std::vector<std::string>>())
        ("f,feature", "enable a custom feature (-fXX flag)",
         cxxopts::value<std::vector<std::string>>())
        ("gnu_extensions", "enable GNU extensions (equivalent to -std=gnu++XX)")
        ("msvc_extensions", "enable MSVC extensions (equivalent to -fms-extensions)")
        ("msvc_compatibility", "enable MSVC compatibility (equivalent to -fms-compatibility)")
        ("fast_preprocessing", "enable fast preprocessing, be careful, this breaks if you e.g. redefine macros in the same file!")
        ("remove_comments_in_macro", "whether or not comments generated by macro are kept, enable if you run into errors");
    // clang-format on
    option_list.parse_positional("file");

    auto options = option_list.parse(argc, argv);
    if (options.count("help"))
        print_help(option_list);
    else if (options.count("version"))
    {
        std::cout << "cppast version " << CPPAST_VERSION_STRING << "\n";
        std::cout << "Copyright (C) Jonathan Müller 2017-2019 <jonathanmueller.dev@gmail.com>\n";
        std::cout << '\n';
        std::cout << "Using libclang version " << CPPAST_CLANG_VERSION_STRING << '\n';
    }
    else if (!options.count("file") || options["file"].as<std::string>().empty())
    {
        print_error("missing file argument");
        return 1;
    }
    else
    {
        // the compile config stores compilation flags
        cppast::libclang_compile_config config;
        if (options.count("database_dir"))
        {
            cppast::libclang_compilation_database database(
                options["database_dir"].as<std::string>());
            if (options.count("database_file"))
                config
                    = cppast::libclang_compile_config(database,
                                                      options["database_file"].as<std::string>());
            else
                config
                    = cppast::libclang_compile_config(database, options["file"].as<std::string>());
        }

        if (options.count("verbose"))
            config.write_preprocessed(true);

        if (options.count("fast_preprocessing"))
            config.fast_preprocessing(true);

        if (options.count("remove_comments_in_macro"))
            config.remove_comments_in_macro(true);

        if (options.count("include_directory"))
            for (auto& include : options["include_directory"].as<std::vector<std::string>>())
                config.add_include_dir(include);
        if (options.count("macro_definition"))
            for (auto& macro : options["macro_definition"].as<std::vector<std::string>>())
            {
                auto equal = macro.find('=');
                auto name  = macro.substr(0, equal);
                if (equal == std::string::npos)
                    config.define_macro(std::move(name), "");
                else
                {
                    auto def = macro.substr(equal + 1u);
                    config.define_macro(std::move(name), std::move(def));
                }
            }
        if (options.count("macro_undefinition"))
            for (auto& name : options["macro_undefinition"].as<std::vector<std::string>>())
                config.undefine_macro(name);
        if (options.count("feature"))
            for (auto& name : options["feature"].as<std::vector<std::string>>())
                config.enable_feature(name);

        // the compile_flags are generic flags
        cppast::compile_flags flags;
        if (options.count("gnu_extensions"))
            flags |= cppast::compile_flag::gnu_extensions;
        if (options.count("msvc_extensions"))
            flags |= cppast::compile_flag::ms_extensions;
        if (options.count("msvc_compatibility"))
            flags |= cppast::compile_flag::ms_compatibility;

        if (options["std"].as<std::string>() == "c++98")
            config.set_flags(cppast::cpp_standard::cpp_98, flags);
        else if (options["std"].as<std::string>() == "c++03")
            config.set_flags(cppast::cpp_standard::cpp_03, flags);
        else if (options["std"].as<std::string>() == "c++11")
            config.set_flags(cppast::cpp_standard::cpp_11, flags);
        else if (options["std"].as<std::string>() == "c++14")
            config.set_flags(cppast::cpp_standard::cpp_14, flags);
        else if (options["std"].as<std::string>() == "c++1z")
            config.set_flags(cppast::cpp_standard::cpp_1z, flags);
        else if (options["std"].as<std::string>() == "c++17")
            config.set_flags(cppast::cpp_standard::cpp_17, flags);
        else if (options["std"].as<std::string>() == "c++2a")
            config.set_flags(cppast::cpp_standard::cpp_2a, flags);
        else if (options["std"].as<std::string>() == "c++20")
            config.set_flags(cppast::cpp_standard::cpp_20, flags);
        else
        {
            print_error("invalid value '" + options["std"].as<std::string>() + "' for std flag");
            return 1;
        }

        // the logger is used to print diagnostics
        cppast::stderr_diagnostic_logger logger;
        if (options.count("verbose"))
            logger.set_verbose(true);

        auto file = parse_file(config, logger, options["file"].as<std::string>(),
                               options.count("fatal_errors") == 1);
        if (!file)
            return 2;
        print_ast(std::cout, *file);
    }
}
catch (const cppast::libclang_error& ex)
{
    print_error(std::string("[fatal parsing error] ") + ex.what());
    return 2;
}