platform/linux/font.c

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#if defined(__linux__) || defined(__FreeBSD__) || defined(__OpenBSD__)
#include <ascii-chat/platform/font.h>
#include <ascii-chat/font.h>
#include <ascii-chat/log/log.h>
#ifndef USE_MUSL
#include <fontconfig/fontconfig.h>
#endif
#include <string.h>
#include <sys/stat.h>
#include <stddef.h>
 
// Fallback font name for fontconfig when a requested font is not found.
// DejaVu Sans Mono ships with the vast majority of distros.
static const char *k_fallback = "DejaVu Sans Mono";
 
static bool is_absolute_path(const char *s) {
  return s && s[0] == '/';
}
static bool file_exists(const char *p) {
  struct stat st;
  return stat(p, &st) == 0;
}
 
#ifndef USE_MUSL
static asciichat_error_t resolve_via_fontconfig(const char *name, char *out, size_t sz) {
  FcConfig *fc = FcInitLoadConfigAndFonts();
  FcPattern *pat = FcNameParse((const FcChar8 *)name);
  if (!pat)
    return SET_ERRNO(ERROR_INVALID_PARAM, "platform_font_resolve: bad name '%s'", name);
 
  FcConfigSubstitute(fc, pat, FcMatchPattern);
  FcDefaultSubstitute(pat);
 
  FcResult result;
  FcPattern *match = FcFontMatch(fc, pat, &result);
  FcPatternDestroy(pat);
 
  if (!match || result != FcResultMatch)
    return SET_ERRNO(ERROR_NOT_FOUND, "platform_font_resolve: no font matching '%s'", name);
 
  FcChar8 *file = NULL;
  if (FcPatternGetString(match, FC_FILE, 0, &file) != FcResultMatch || !file) {
    FcPatternDestroy(match);
    return SET_ERRNO(ERROR_NOT_FOUND, "platform_font_resolve: fontconfig matched but no file");
  }
  snprintf(out, sz, "%s", (const char *)file);
  log_debug("platform_font_resolve: '%s' → %s", name, out);
  FcPatternDestroy(match);
  return ASCIICHAT_OK;
}
#endif
 
asciichat_error_t platform_font_resolve(const char *spec, char *out, size_t out_size, bool *out_is_path,
                                        const uint8_t **out_font_data, size_t *out_font_data_size) {
  // If no font is specified, use the bundled default font (DejaVu Sans Mono) for render-file output.
  // This ensures render-file always has a suitable fallback font available.
  const char *eff = (spec && spec[0]) ? spec : "default";
 
  if (out_font_data)
    *out_font_data = NULL;
  if (out_font_data_size)
    *out_font_data_size = 0;
 
  if (is_absolute_path(eff)) {
    snprintf(out, out_size, "%s", eff);
    *out_is_path = true;
    return file_exists(out) ? ASCIICHAT_OK : SET_ERRNO(ERROR_NOT_FOUND, "render-font: not found: %s", out);
  }
 
  // Check for bundled font names ("matrix" or "default")
  if (strcmp(eff, "matrix") == 0) {
    if (out_font_data)
      *out_font_data = g_font_matrix_resurrected;
    if (out_font_data_size)
      *out_font_data_size = g_font_matrix_resurrected_size;
    snprintf(out, out_size, "matrix");
    *out_is_path = false;
    log_info("platform_font_resolve: USING MATRIX FONT - g_font_matrix_resurrected=%p (size=%zu), g_font_default=%p "
             "(size=%zu)",
             (void *)g_font_matrix_resurrected, g_font_matrix_resurrected_size, (void *)g_font_default,
             g_font_default_size);
    return ASCIICHAT_OK;
  }
 
  if (strcmp(eff, "default") == 0) {
    if (out_font_data)
      *out_font_data = g_font_default;
    if (out_font_data_size)
      *out_font_data_size = g_font_default_size;
    snprintf(out, out_size, "default");
    *out_is_path = false;
    log_info("platform_font_resolve: USING DEFAULT FONT - g_font_default=%p (size=%zu), g_font_matrix_resurrected=%p "
             "(size=%zu)",
             (void *)g_font_default, g_font_default_size, (void *)g_font_matrix_resurrected,
             g_font_matrix_resurrected_size);
    return ASCIICHAT_OK;
  }
 
#ifndef USE_MUSL
  *out_is_path = true;
  asciichat_error_t err = resolve_via_fontconfig(eff, out, out_size);
  if (err != ASCIICHAT_OK && strcmp(eff, k_fallback) != 0) {
    log_warn("platform_font_resolve: '%s' not found, trying '%s'", eff, k_fallback);
    err = resolve_via_fontconfig(k_fallback, out, out_size);
  }
 
  // Fallback chain: system fonts → bundled default font
  if (err != ASCIICHAT_OK) {
    log_warn("platform_font_resolve: system font resolution failed, using bundled default font");
    if (out_font_data)
      *out_font_data = g_font_default;
    if (out_font_data_size)
      *out_font_data_size = g_font_default_size;
    out[0] = '\0';
    *out_is_path = false;
    err = ASCIICHAT_OK;
  }
 
  return err;
#else
  // musl static builds: fontconfig not available, use bundled default font
  log_debug("platform_font_resolve: using bundled default font (musl build, no fontconfig)");
  if (out_font_data)
    *out_font_data = g_font_default;
  if (out_font_data_size)
    *out_font_data_size = g_font_default_size;
  out[0] = '\0';
  *out_is_path = false;
  return ASCIICHAT_OK;
#endif
}
#endif