// SPDX-License-Identifier: GPL-3.0-or-later
// SPDX-FileCopyrightText: 2025 ai-ad4 and the FreePDFEditor contributors
//
// SubsetGrowth.h — Spike C (§14 step 6): grow an existing embedded subset
// font with a new glyph using hb-subset, and verify the result.
//
// The scenario: a PDF page embeds a subset font containing only the glyphs
// originally used (say "Hello"). The user types "Ω" — that glyph is not in
// the subset. Per §4.2 resolution ladder step 1, we grow the subset from
// the installed full font (DejaVu Sans here) using hb-subset and embed the
// new subset. This spike proves the growth works and the result is a valid
// font with the new glyph and a correct cmap.

#ifndef FREEPDFEDITOR_SPIKE_C_SUBSETGROWTH_H
#define FREEPDFEDITOR_SPIKE_C_SUBSETGROWTH_H

#include <cstddef>
#include <string>
#include <vector>

namespace freepdfeditor::spike::c {

struct GrowthResult {
    bool ok = false;
    std::string error;
    std::size_t original_glyph_count = 0;  // glyphs in the initial subset
    std::size_t grown_glyph_count = 0;     // glyphs after adding the new char
    std::size_t original_font_bytes = 0;
    std::size_t grown_font_bytes = 0;
    bool new_glyph_present = false;        // does the grown subset contain U+03A9?
    bool new_glyph_renders = false;        // can FreeType load its outline?
    std::string original_subset_tag;       // e.g. "AAAAAA+"
    std::string grown_subset_tag;
};

// Run the subset-growth scenario:
//  1. Build an initial subset of `font_path` containing the glyphs for
//     "Hello" (the "originally embedded" subset).
//  2. Grow it by adding U+03A9 (GREEK CAPITAL LETTER OMEGA) — the character
//     the user typed that wasn't in the original subset.
//  3. Verify the grown subset: it must contain the new glyph, have a correct
//     cmap mapping U+03A9 → a glyph id, and FreeType must be able to load
//     that glyph's outline (it renders).
GrowthResult grow_subset(const std::string& font_path);

} // namespace freepdfeditor::spike::c

#endif // FREEPDFEDITOR_SPIKE_C_SUBSETGROWTH_H