#pragma once

#include <vector>
#include <map>
#include <string>
#include <regex>
#include <tuple>
#include <set>

inline const std::string at_s {"@"};
inline const std::string at2_s { "@@" };
inline const std::string at3_s { "@@@" };
inline const std::string bar_s { "|" };
inline const std::string open_s { R"(\()" };
inline const std::string close_s { R"(\))" };
inline const std::string karg_s { "*" };
inline const std::string read_s { "read" };
inline const std::string eval_s { "eval" };
inline const std::string cond_s { "cond" };
inline const std::string lit_s { "lit" };

inline const std::string hat_s { "^" };

inline const std::string ignore_line_s { "#" };
inline const std::string ignore_begin_s { R"(#\[)" };
inline const std::string ignore_end_s { R"(\]#)" };
inline const std::string ignore_rest_s { "##" };

inline const std::string ws_remove_s { "#-" };
inline const std::string ws_space_s { R"(#\+\d*)" };
inline const std::string ws_newline_s { R"(#/\d*)" };

// const std::string kname = "[a-zA-Z]+[a-zA-Z0-9_.]*";
// const std::string dname = "[a-zA-Z]+[a-zA-Z0-9_]*";

// const std::string k_name = R"([^^@#|\:]+)";
inline const std::string definition_name = R"([a-zA-Z][a-zA-Z0-9_.]*)";
// The name at the START of a definition may carry a comma-separated list of
// targets ("@@table.html,tex"), so its katom runs through commas.  This is
// deliberately looser than the grammar: katomization's job is to delimit
// the katom, and parse_name() in klammer.cpp validates the list, where a
// malformed one can be reported with its location.  The comma stays out of
// definition_name itself -- that pattern also delimits klammer APPLICATIONS,
// option names and "*arg*" variables, where a comma is ordinary writer text.
// "*" is here for the same reason: "@@date.*" declares a klammer for every
// target explicitly, and "*" is a Klammertext special everywhere else.
inline const std::string definition_begin_name = R"([a-zA-Z][a-zA-Z0-9_.,*]*)";


enum class katom_t {
    space,
    word,
    newline,
    text, 
    apply_begin,
    apply_end,
    bar,
    double_bar,
    option_name,
    read_begin,
    eval_begin,
    cond_begin,
    define_begin,
    define_end,
    klammer_definition,
    klammer_instance,
    klammer_override,
    klammer_default,
    karg,
    machine_begin,
    machine_end,
    ignore_line,
    ignore_begin,
    ignore_end,
    ignore_rest,
    ws_remove,
    ws_space,
    ws_newline,
    special,
    nonascii,
    literal_begin,
    literal_end,
    ws_added,
    literal,
    eval_result,
    replaced,
    ignored,
};


class Ktype;

inline std::map<katom_t, std::string> katom_type_names {};
inline std::vector<katom_t> katom_type_list {};

class Ktype {
public:
//    Ktype() = default;
    Ktype(katom_t type, std::string name, std::string pattern, bool use_equal = false)
            : m_type(type),
              m_name(name),
              m_pattern(pattern),
              m_use_equal(use_equal),
              m_rgx(std::regex(pattern)) {
        katom_type_list.push_back(type);
        katom_type_names.insert({m_type, m_name});
    }
    // A description used to be the fourth argument.  A string literal there
    // would now convert to bool and silently set use_equal, so it is refused.
    Ktype(katom_t, std::string, std::string, const char*) = delete;
    bool match(const std::string& s) const {
        return m_use_equal ? s == m_pattern : std::regex_match(s, m_rgx);
    }
    katom_t m_type;
    std::string m_name;
    std::string m_pattern;
    bool m_use_equal;
    std::regex m_rgx;
};

inline const
std::vector<Ktype> katom_types {
    Ktype(katom_t::space, "space", " ", false),
    Ktype(katom_t::word, "word", "[a-zA-Z]+", false),
    Ktype(katom_t::newline, "newline", "\n", false),
    Ktype(katom_t::bar, "bar", "\\|", false),
    Ktype(katom_t::double_bar, "double-bar", "\\|\\|", false),
    Ktype(katom_t::read_begin, "read-begin", at_s+read_s, false),
    Ktype(katom_t::eval_begin, "eval-begin", at_s+eval_s, false),
    Ktype(katom_t::cond_begin, "cond-begin", at_s+cond_s, false),
    Ktype(katom_t::apply_begin, "apply-begin", at_s + definition_name),
    Ktype(katom_t::apply_end, "apply-end", "(" + definition_name + ")?" + at_s),
    Ktype(katom_t::option_name, "option-name", ":" + definition_name),
    Ktype(katom_t::define_begin, "define-begin", at2_s + definition_begin_name),
    Ktype(katom_t::define_end, "define-end", "(" + definition_name + ")?" + at2_s),
    Ktype(katom_t::klammer_default, "klammer-default", "::::"),
    Ktype(katom_t::klammer_override, "klammer-override", ":::"),
    Ktype(katom_t::klammer_definition, "klammer-definition", ":"),
    Ktype(katom_t::klammer_instance, "klammer-instance", "::"),

    Ktype(katom_t::karg, "klammer-arg", "\\*" + definition_name +"\\*"),
    Ktype(katom_t::machine_begin, "machine-begin", at3_s + definition_name),
    Ktype(katom_t::machine_end, "machine-end", "(" + definition_name + ")?" + at3_s),
    Ktype(katom_t::ignore_begin, "ignore-begin", ignore_begin_s),
    Ktype(katom_t::ignore_end, "ignore-end", ignore_end_s),
    Ktype(katom_t::ignore_rest, "ignore-rest", ignore_rest_s),
    Ktype(katom_t::ignore_line, "ignore-line", ignore_line_s),
    Ktype(katom_t::ws_remove, "ws-remove", ws_remove_s),
    Ktype(katom_t::ws_space, "ws-space", ws_space_s),
    Ktype(katom_t::ws_newline, "ws-newline", ws_newline_s),
    Ktype(katom_t::special, "special-char", R"(\^[@|#^:*])"),
    //Ktype(katom_t::nonascii, "non-ascii-char", R"(\^\w(?:.|\^))", "Non-ASCII character"),
    // The second alternative is the "^...^" delimited form: a code point
    // (^263A^, 4-6 hex digits) OR a mnemonic (^s^, ^oe^).  Its character
    // class is [A-Za-z0-9], not [A-Fa-f0-9], because a mnemonic is not
    // hex: "^oe^" matched NEITHER alternative and so was not a katom at
    // all, fell through to the "non-diacritic non-ascii" rewrite rule,
    // which pads it with whitespace and hands back the same single word --
    // and make_katoms_from_word() then recursed on the identical string
    // until the stack died (SIGSEGV, no message).  The two entries that
    // appeared to work, ^ae^ and ^AE^, did so only because "ae" happens to
    // be hex digits; they were being katomized as CODE POINTS and rendered
    // correctly only because encode() runs process_extended_latin() before
    // process_unicode_codepoint().  Which of the two a form means is
    // decided there, by the tables, not here -- katomization's job is only to
    // recognize the shape.  A shape that resolves to no character at all is
    // a located error, raised at the end of encode().
    Ktype(katom_t::nonascii, "non-ascii-char", R"((\^(\w(?:.|\^)))|(\^[A-Za-z0-9]{1,6}\^))"),

    // Ktype(katom_t::word, "word", R"([a-z][a-z0-9_]*)", "Lower-case letters, numbers, or underscore"),
    // Ktype(katom_t::text, "text",

    Ktype(katom_t::literal_begin, "literal-begin", R"(\^')"),
    Ktype(katom_t::literal_end, "literal-end", R"('\^)"),
    Ktype(katom_t::text, "text", R"([^^@#|]+)"), // spaces, @, #, |, or ^, 

    Ktype(katom_t::ws_added, "ws-added", "<space> or \\n"),
    Ktype(katom_t::literal, "literal", ""),
    Ktype(katom_t::eval_result, "eval-result", ""),
    
    Ktype(katom_t::replaced, "replaced", ""),
    Ktype(katom_t::ignored, "ignored", ""),
//    Ktype(katom_t::undefined, "undefined", "", "Undefined pattern")
};


// The human-facing description of the katom types, and the ONLY one: class
// Ktype above holds what the program needs (type, name, regex), this holds
// what a reader is told, and katom_t joins them.  The pattern and the
// description are Klammertext, rendered by katom_descriptions() in
// ref/reflect.cpp (kdesc --katoms; a Handbook chapter).  A title is
// Klammertext too, without styling -- the generator styles every title alike.
//
// The ORDER is the display order, from what every author meets to what only
// a programmer does, and it is also the order of the katom_t enumerators:
// the table's Index column is the enum value, which is the subscript kdiag
// prints.  tst/ktype_test.cpp asserts both halves of the tie -- every type
// in katom_types described exactly once, and the indices increasing.
struct Katom_type_description {
    katom_t m_type;
    std::string m_pattern;
    std::string m_description;
};

struct Katom_type_group {
    std::string m_title;
    std::vector<Katom_type_description> m_types;
};

inline const
std::vector<Katom_type_group> katom_type_groups {
    {"Plain text", {
        {katom_t::space,              "@symb-space",                                     "One space character"},
        {katom_t::word,               "@symb only-letters @",                            "Text only containing letters"},
        {katom_t::newline,            "\\n",                                             "One newline character"},
        {katom_t::text,               "@symb no-special-chars @",                        "No special characters, whitespace, or an initial colon"}}},
    {"Klammer application", {
        {katom_t::apply_begin,        "^@ #- @symb-name",                                "Beginning of a klammer call"},
        {katom_t::apply_end,          "^@ @ri-or @symb-name #- ^@",                      "End of a klammer call"},
        {katom_t::bar,                "^|",                                              "Bar character used as positional argument separator"},
        {katom_t::double_bar,         "^|^|",                                            "Separator for compound positional arguments"},
        {katom_t::option_name,        ": #- @symb-name",                                 "Name of an optional argument"},
        {katom_t::read_begin,         "@t ^@read @",                                     "Beginning of the file input klammer"},
        {katom_t::eval_begin,         "@t ^@eval @",                                     "Beginning of the evaluation klammer"},
        {katom_t::cond_begin,         "@t ^@cond @",                                     "Beginning of the conditional (if/then/else) klammer"}}},
    {"Klammer definition", {
        {katom_t::define_begin,       "^@^@ #- @symb-name",                              "Beginning of a klammer definition"},
        {katom_t::define_end,         "^@^@ @ri-or @symb-name #- ^@^@",                  "End of a klammer definition"},
        {katom_t::klammer_definition, ":",                                               "Klammer definition, including parameters"},
        {katom_t::klammer_instance,   "::",                                              "Klammer definition using previously defined parameters"},
        {katom_t::klammer_override,   ":::",                                             "Override existing klammer definition"},
        {katom_t::klammer_default,    "::::",                                            "Define klammer default value for possible override"},
        {katom_t::karg,               "* #- @symb-name #- *",                            "Klammer argument in klammer body definition"}}},
    {"System commands", {
        {katom_t::machine_begin,      "^@^@^@ #- @symb-name",                            "Beginning of a system command"},
        {katom_t::machine_end,        "^@^@^@ @ri-or @symb-name #- ^@^@^@",             "End of a system command"}}},
    {"Text removal and whitespace", {
        {katom_t::ignore_line,        "^#",                                              "Remove all text to the first newline, inclusive"},
        {katom_t::ignore_begin,       "^#[",                                             "Beginning of text to remove"},
        {katom_t::ignore_end,         "]^#",                                             "End of text to remove"},
        {katom_t::ignore_rest,        "^#^#",                                            "Remove all text to the end of file or string"},
        {katom_t::ws_remove,          "^#-",                                             "Remove all whitespace at this point"},
        {katom_t::ws_space,           "^#+ @ri-or ^#+ #- @symb-n",                       "Remove all whitespace, leaving @symb-n spaces (default: 1)"},
        {katom_t::ws_newline,         "^#/ @ri-or ^#/ #- @symb-n",                       "Remove all whitespace, leaving @symb-n newlines (default: 1)"}}},
    {"Special characters and literal text", {
        {katom_t::special,            "^@,  ^|, ^#, ^:, @ri-or ^^",                      "Klammertext special character treated as regular text"},
        {katom_t::nonascii,           "^^ #- @symb-code @ri-or ^^ #- @symb-code #- ^^",  "Non-ASCII character"},
        {katom_t::literal_begin,      "^^ #- '",                                         "Begin unprocessed text"},
        {katom_t::literal_end,        "'#- ^^",                                          "End unprocessed text"}}},
    {"Types assigned during processing", {
        {katom_t::ws_added,           "@symb-space @ri-or \\n",                          "Added whitespace characters from @t ^#+ @ and @t ^#/ @"},
        {katom_t::literal,            "@symb any-text @",                                "Literal katom (type changed by @t ^^ #- '...'#- ^^ @ #- )"},
        {katom_t::eval_result,        "@symb any-text @",                                "Katom produced by @t ^@eval @ klammer"},
        {katom_t::replaced,           "@symb any-text @",                                "A katom replaced by definitions or klammers"},
        {katom_t::ignored,            "@symb any-text @",                                "A katom ignored by the action of a text-removal katom"}}}
};

inline const
std::set<katom_t> printable_katom_types {
    katom_t::word,
    katom_t::space,
    katom_t::newline,
    katom_t::literal,
    katom_t::ws_added
};

inline const
std::set<katom_t> open_level {
    katom_t::literal_begin,
    katom_t::read_begin,
    katom_t::eval_begin,
    katom_t::cond_begin,
    katom_t::apply_begin,
    katom_t::define_begin,
    katom_t::machine_begin,
    katom_t::ignore_begin
};

inline const
std::set<katom_t> close_level {
    katom_t::literal_end,
    katom_t::apply_end,
    katom_t::apply_end,
    katom_t::apply_end,
    katom_t::apply_end,
    katom_t::define_end,
    katom_t::machine_end,
    katom_t::ignore_end
};

inline
std::map<katom_t, katom_t> katom_spans {
    { katom_t::literal_begin, katom_t::literal_end },
    { katom_t::read_begin, katom_t::apply_end },
    { katom_t::eval_begin, katom_t::apply_end },
    { katom_t::cond_begin, katom_t::apply_end },
    { katom_t::apply_begin, katom_t::apply_end },
    { katom_t::define_begin, katom_t::define_end },
    { katom_t::machine_begin, katom_t::machine_end },
    { katom_t::ignore_begin, katom_t::ignore_end }
};


bool is_active(katom_t t);
bool is_printable(katom_t type);

bool is_deftype(katom_t type);

const Ktype& type_to_katom_instance(katom_t type);
std::string type_to_name(katom_t type);