#include <tuple>

#include "argv.h"
#include "file.h"
#include "log.h"
#include "machine.h"

using namespace std::string_literals;

fs::path construct_command_pathname(char* command)
{
    // The pseudo source file for command-line string input (-s, kdiag's
    // input): a file IN THE CWD named after the command, so that a relative
    // @read in string input resolves against the directory the user ran the
    // command from -- the string-input analog of "a document's relative
    // names resolve against the document".  The basename matters: the
    // former "<cwd>/<argv[0]>" string concatenation anchored resolution at
    // the BINARY's directory whenever argv[0] was absolute
    // (/usr/local/bin/ktext, a wrapper script), so every relative @read in
    // -s input searched bin/ instead of the cwd.
    return fs::current_path() / fs::path(command).filename();
}

void set_verbose_level(int argc, char* argv[])
{
    //command_name = absolute_pathname(argv[0]);
    command_name = std::string(argv[0]);
    command_pathname = construct_command_pathname(argv[0]);
    //std::cout << "set_verbose_level: " << command_pathname << "\n";

    Argv args {};
    args.opt("v", "'verbosity'", "level", "0", "'verbosity'");
    args.parse(argc, argv, false);
    verbose_level = args.as_verbosity("v");
}

bool show_usage(int argc, char* argv[])
{
    return argc == 1 || (argc == 3 && std::string(argv[1]) == "-v"s);
}

std::string construct_output_filename(
    const std::string& output_dir, const std::string& output_basename, const std::string& target)
{
    std::string result {};
    if (target == "html") {
        result = output_dir + "/" + output_basename + "/index.html";
    } else {
        result = output_dir + "/" + output_basename + "." + target;
    }
    return result;
}

bool only_definitions(std::vector<std::string> filenames)
{
    if (filenames.empty()) return false;
    bool result = true;
    for (auto f : filenames) {
        if (fs::path(f).extension() != ".k") {
            result = false;
            break;
        }
    }
    return result;
}

std::tuple<std::string, std::string, std::string, std::string, bool, bool>
parse_args(
    const std::vector<std::string>& input_filenames, std::string target, std::string output_basename, bool display_only)
{
    // output_dir
    std::string output_target = target;
    std::string output_dir = "";
    std::string ext = extension(output_basename);
    // std::string output_filename = "";
    bool write_files = true;
    if (target.empty() && output_basename.empty()) {
        output_target = "any";
    }
    if (output_basename == "-") {
        write_files = false;
    } else if (!output_basename.empty()) {
        output_dir = file_directory(output_basename);
        output_basename = file_basename(output_basename);
    } else if (!input_filenames.empty()) {
        // No -o: output goes next to the input file ("" -- an input with no
        // directory component -- resolves to cwd below).
        output_dir = file_directory(input_filenames[0]);
        output_basename = file_basename(input_filenames[0]);
    }
    output_dir = absolute_pathname(output_dir);
        
    if (output_target.empty()) {
        target = ext;
    }

    std::string output_filename =
        construct_output_filename(output_dir, output_basename, target);

    if (output_basename.empty() && input_filenames.empty()) {
        display_only = true;
    } else if (only_definitions(input_filenames)) {
        display_only = true;
    }

    std::vector<std::pair<std::string,std::string>> vars = {
        {"Output target", output_target},
        {"Output directory", output_dir},
        {"Output basename", output_basename},
        {"Output filename", output_filename},
        {"Write file", write_files ? "true" : "false"}};

    int verbose = 1;
    for (auto [label, value] : vars) {
        if (label == "Output filename") {
            //verbose = 2;
        }
        (void)K::log(int(verbose), label + ":", value);
    }
    return {output_target, output_dir, output_basename, output_filename, write_files, display_only};
}


void load_klammersets(Machine& machine, const strings_t& symbols)
{
    // "none" is the absence of a klammerset, not the name of one, so it says
    // nothing about what should be loaded ALONGSIDE it: written first it would
    // silently discard the rest of the list, written last it would be looked up
    // as a symbol and reported missing.  Both readings are wrong, so neither is
    // guessed at -- "none" is accepted only alone.
    if (is_in("none"s, symbols) && symbols.size() > 1) {
        throw Klammerset_error(
            "The klammerset \"none\" cannot be combined with other klammersets: "
            "it means that none is loaded. Give \"none\" alone, or name only the "
            "klammersets to load.",
            Locator::none());
    }
    if (symbols.empty()) {
        // Which klammerset was loaded, and from where, is a DERIVED value: the
        // user wrote no --klammersets at all and got the SKS from
        // $KLAMMERTEXT_HOME.  Only the symbol branch below reported its
        // resolution, so the commonest case -- the default -- said nothing.
        std::string sks = machine.m_state.value("KLAMMERTEXT_HOME") + "/sks/sks.k";
        (void)K::log(1, "Klammerset (default): " + sks);
        machine.read(fs::path(sks));
    } else if (symbols[0] == "none") {
        (void)K::log(1, "Klammersets: none");
    } else {
        // The whitespace-delimited words in symbols must be klammerset symbols:
        for (const auto& symbol : symbols) {
            // Same guard as ":requires" (Machine::load_klammerset_files): a set
            // named twice on the command line is loaded once.
            if (machine.m_klammersets.has(symbol)) {
                (void)K::log(1, "Klammerset \"" + symbol + "\": already loaded, skipped");
                continue;
            }
            std::string klammerset_filename = resolve_klammerset_symbol(
                symbol, machine.m_state.value("K_input_dir"), Locator::none()).string();
            // Symbol -> file is the search path's answer, and the search
            // path has three stages with shadowing: the file it landed on is
            // exactly what a user cannot read off "--klammersets x".
            (void)K::log(1, "Klammerset \"" + symbol + "\": " + klammerset_filename);
            machine.read(fs::path(klammerset_filename));
        }
    }
}
