Crafter.Review/interfaces/Crafter.Review-Text.cppm

// SPDX-License-Identifier: AGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®

export module Crafter.Review:Text;
import std;
import :Json;

// The text, number, URL and path semantics every other partition relies on.
// Where a result reaches a prompt, a reuse key, a shared file or an exit code
// it is decided by these exact rules — Unicode whitespace in Strip(), U+2028
// in SplitLines(), code points in Length(), half-even Round(), FnMatch()'s
// character classes — never by the nearest C++ equivalent. tests/Text checks
// every function against the reference vectors in tests/Text/fixture.
//
// Text is UTF-8 in std::string. Lengths and indices are in code points.
//
// Lower() maps Greek capital sigma to σ everywhere: it never writes the
// final form ς.
export namespace Crafter::Review::Dyn {
    // ---- UTF-8 -------------------------------------------------------------
    // Each maximal subpart of an ill-formed sequence becomes one U+FFFD, the
    // Unicode Standard's recommended practice.
    std::u32string Decode(std::string_view utf8);
    std::string Encode(std::u32string_view text);
    std::string Encode(char32_t c);
    // Well-formed UTF-8: no overlong forms, no surrogates, nothing above
    // U+10FFFF.
    bool IsUtf8(std::string_view bytes);
    // bytes.decode('utf-8', 'replace').
    std::string DecodeReplace(std::string_view bytes);
    // len()
    std::size_t Length(std::string_view text);
    // The code points from start to end: a negative index counts from the
    // end, and both are clipped to the text.
    std::string Slice(std::string_view text, std::int64_t start, std::optional<std::int64_t> end = std::nullopt);

    // ---- characters ----------------------------------------------------------
    bool IsSpace(char32_t c);
    bool IsLineBreak(char32_t c);
    bool IsDecimal(char32_t c);
    // The digit's value, -1 for a character that is not a decimal digit.
    std::int32_t DecimalValue(char32_t c);
    bool IsPrintable(char32_t c);
    // The lowercase ASCII letter `c` matches case-insensitively, or '\0':
    // ASCII letters, and the four code points outside ASCII that fold onto
    // one (İ ı → i, ſ → s, K → k).
    char IgnoreCaseLetter(char32_t c);

    // ---- str methods ----------------------------------------------------------
    // strip()/lstrip()/rstrip(): Unicode whitespace.
    std::string Strip(std::string_view text);
    std::string LStrip(std::string_view text);
    std::string RStrip(std::string_view text);
    // strip(chars): the code points of `chars`.
    std::string Strip(std::string_view text, std::string_view chars);
    std::string LStrip(std::string_view text, std::string_view chars);
    std::string RStrip(std::string_view text, std::string_view chars);
    // split(): runs of Unicode whitespace, no empty pieces.
    std::vector<std::string> Split(std::string_view text);
    // split(sep, maxsplit) / rsplit(sep, maxsplit): every piece, empty ones
    // included; a negative maxSplit splits at every separator.
    std::vector<std::string> Split(std::string_view text, std::string_view separator, std::int64_t maxSplit = -1);
    std::vector<std::string> RSplit(std::string_view text, std::string_view separator, std::int64_t maxSplit = -1);
    // splitlines(keepends): \n, \r, \r\n, \v, \f, \x1c-\x1e, \x85, U+2028,
    // U+2029; no empty piece after a final line break.
    std::vector<std::string> SplitLines(std::string_view text, bool keepEnds = false);
    std::string Lower(std::string_view text);
    std::string Upper(std::string_view text);
    // count(sub): non-overlapping; an empty `sub` counts len() + 1.
    std::size_t Count(std::string_view text, std::string_view sub);
    std::string Replace(std::string_view text, std::string_view from, std::string_view to);
    std::string Join(std::span<const std::string> parts, std::string_view separator);

    // ---- reading text files ----------------------------------------------------
    // A text file, read whole: strict UTF-8 — an invalid byte throws
    // std::runtime_error naming the file and the offset — and universal
    // newlines.
    std::string ReadText(const std::filesystem::path& path);
    // \r\n and a lone \r become \n, as text mode reads them.
    std::string UniversalNewlines(std::string_view text);

    // ---- numbers ------------------------------------------------------------------
    // A float as its shortest digits that round-trip; an exponent below 1e-4
    // and from 1e16 up; ".0" on an integral value; inf, nan.
    std::string FloatRepr(double value);
    // value to `digits` decimals: correctly rounded, half to even on exact
    // ties.
    double Round(double value, std::int32_t digits);
    // value to the nearest integer, half to even.
    std::int64_t RoundToInt(double value);
    // An integer or a float from text: surrounding Unicode whitespace ignored,
    // Unicode decimal digits accepted, single underscores between digits
    // allowed. nullopt for anything else (and, for an integer, beyond 64 bits).
    std::optional<std::int64_t> ParseInt(std::string_view text);
    std::optional<double> ParseFloat(std::string_view text);
    // The ValueError messages for those.
    std::string IntError(std::string_view text);
    std::string FloatError(std::string_view text);

    // ---- repr ----------------------------------------------------------------------
    std::string Repr(std::string_view text);
    // A JSON value printed for a message: objects as {'key': value}, strings
    // quoted, true, false and null as True, False and None.
    std::string ReprValue(const Json& value);

    // ---- shell patterns ---------------------------------------------------------------
    // A shell-style pattern: case-sensitive, `*` crosses `/`, `[!...]` negates,
    // an unclosed `[` is literal and a reversed range matches nothing.
    bool FnMatch(std::string_view name, std::string_view pattern);

    // ---- URLs ---------------------------------------------------------------------------
    struct SplitUrl {
        std::string scheme;
        std::string netloc;
        std::string path;
        std::string query;
        std::string fragment;
        // .hostname: lowercased, nullopt when there is none.
        std::optional<std::string> Hostname() const;
        std::optional<std::string> Username() const;
        std::optional<std::string> Password() const;
        // .port: nullopt for none; std::invalid_argument with a ValueError
        // message for one that is not a number or out of range.
        std::optional<std::int32_t> Port() const;
    };
    // A URL's scheme, netloc, path, query and fragment. Throws
    // std::invalid_argument with a ValueError message for unbalanced or
    // invalid brackets.
    SplitUrl UrlSplit(std::string_view url);
    // unquote(text): %XX sequences decoded as UTF-8, bad bytes replaced.
    std::string Unquote(std::string_view text);

    // ---- natural sort ---------------------------------------------------------------------
    // A name cut into digit runs and the text between them, compared element
    // by element, a digit run by its value.
    struct NaturalKey {
        std::vector<std::variant<std::string, std::int64_t>> parts;
        std::strong_ordering operator<=>(const NaturalKey& other) const = default;
        bool operator==(const NaturalKey& other) const = default;
    };
    NaturalKey Natural(std::string_view name);

    // ---- POSIX paths -----------------------------------------------------------------------
    std::string NormPath(std::string_view path);
    // Against the current directory, lexically: symlinks are not resolved.
    std::string AbsPath(std::string_view path);
    std::string RelPath(std::string_view path, std::string_view start = ".");
    std::string BaseName(std::string_view path);
    std::string DirName(std::string_view path);
    std::string JoinPath(std::string_view a, std::string_view b);

    // ---- errno texts -------------------------------------------------------------------------
    // "[Errno 111] Connection refused": an errno as a message prints it.
    std::string ErrnoText(std::int32_t code);
}