% Font family registry with on-demand local/global loading.
% Public interface:
%   \FontRegisterFamily{ id=..., local={...}, global={...}, ... }
%   \UseFont{id}[local|global]

\RequirePackage{expl3}
\RequirePackage{xparse}

\ExplSyntaxOn

\prop_new:N \g__font_family_local_prop
\prop_new:N \g__font_family_global_prop
\prop_new:N \g__font_family_default_prop
\prop_new:N \g__font_family_loaded_prop
\prop_new:N \g__font_family_range_profile_prop
\prop_new:N \g__font_family_global_route_prop
\prop_new:N \g__font_range_profile_keys_prop
\prop_new:N \g__font_range_key_blocks_prop
\prop_new:N \g__font_range_key_owner_prop
\prop_new:N \g__font_range_key_chain_prop

\tl_new:N \l__font_family_id_tl
\tl_new:N \l__font_family_local_tl
\tl_new:N \l__font_family_global_tl
\tl_new:N \l__font_family_default_mode_tl
\tl_new:N \l__font_family_range_profile_tl
\tl_new:N \l__font_family_global_route_tl
\tl_new:N \l__font_family_owned_range_keys_tl
\tl_new:N \l__font_family_owned_unicode_blocks_tl
\tl_new:N \l__font_family_flat_decl_tl

\cs_new_protected:Npn \__font_family_reset:
  {
    \tl_clear:N \l__font_family_id_tl
    \tl_clear:N \l__font_family_local_tl
    \tl_clear:N \l__font_family_global_tl
    \tl_clear:N \l__font_family_default_mode_tl
    \tl_clear:N \l__font_family_range_profile_tl
    \tl_clear:N \l__font_family_global_route_tl
    \tl_clear:N \l__font_family_flat_decl_tl
  }

\cs_new_protected:Npn \__font_family_flat_append:nn #1#2
  {
    \tl_if_blank:nF {#2}
      { \tl_put_right:Nn \l__font_family_flat_decl_tl { #1 = {#2}, } }
  }

\keys_define:nn { font/family }
  {
    id           .tl_set:N = \l__font_family_id_tl,
    local        .tl_set:N = \l__font_family_local_tl,
    global       .tl_set:N = \l__font_family_global_tl,
    defaultmode  .tl_set:N = \l__font_family_default_mode_tl,
    rangeprofile .tl_set:N = \l__font_family_range_profile_tl,
    globalroute  .tl_set:N = \l__font_family_global_route_tl,
    command      .code:n = { \__font_family_flat_append:nn { command } {#1} },
    name         .code:n = { \__font_family_flat_append:nn { name } {#1} },
    path         .code:n = { \__font_family_flat_append:nn { path } {#1} },
    regular      .code:n = { \__font_family_flat_append:nn { regular } {#1} },
    bold         .code:n = { \__font_family_flat_append:nn { bold } {#1} },
    italic       .code:n = { \__font_family_flat_append:nn { italic } {#1} },
    bolditalic   .code:n = { \__font_family_flat_append:nn { bolditalic } {#1} },
    sans         .code:n = { \__font_family_flat_append:nn { sans } {#1} },
    sansbold     .code:n = { \__font_family_flat_append:nn { sansbold } {#1} },
    sansitalic   .code:n = { \__font_family_flat_append:nn { sansitalic } {#1} },
    sansbolditalic .code:n = { \__font_family_flat_append:nn { sansbolditalic } {#1} },
    mono         .code:n = { \__font_family_flat_append:nn { mono } {#1} },
    monobold     .code:n = { \__font_family_flat_append:nn { monobold } {#1} },
    script       .code:n = { \__font_family_flat_append:nn { script } {#1} },
    language     .code:n = { \__font_family_flat_append:nn { language } {#1} },
    scriptclass  .code:n = { \__font_family_flat_append:nn { scriptclass } {#1} },
    inlineaxis   .code:n = { \__font_family_flat_append:nn { inlineaxis } {#1} },
    inlinedirection .code:n = { \__font_family_flat_append:nn { inlinedirection } {#1} },
    blockprogression .code:n = { \__font_family_flat_append:nn { blockprogression } {#1} },
    preservespaces .code:n = { \__font_family_flat_append:nn { preservespaces } {#1} },
    inlinebehavior .code:n = { \__font_family_flat_append:nn { inlinebehavior } {#1} },
    layout       .code:n = { \__font_family_flat_append:nn { layout } {#1} },
    verticalstrategy .code:n = { \__font_family_flat_append:nn { verticalstrategy } {#1} },
    verticalrotation .code:n = { \__font_family_flat_append:nn { verticalrotation } {#1} },
    verticalorigin .code:n = { \__font_family_flat_append:nn { verticalorigin } {#1} },
    verticaltopcorrection .code:n = { \__font_family_flat_append:nn { verticaltopcorrection } {#1} },
    features     .code:n = { \__font_family_flat_append:nn { features } {#1} },
    cjkfallback  .code:n = { \__font_family_flat_append:nn { cjkfallback } {#1} },
    cjkfallbacks .code:n = { \__font_family_flat_append:nn { cjkfallback } {#1} },
    backend      .code:n = { \__font_family_flat_append:nn { backend } {#1} },
    fallbackmode .code:n = { \__font_family_flat_append:nn { fallbackmode } {#1} },
    specialmodule .code:n = { \__font_family_flat_append:nn { specialmodule } {#1} },
    specialbuilder .code:n = { \__font_family_flat_append:nn { specialbuilder } {#1} },
    externalcommand .code:n = { \__font_family_flat_append:nn { externalcommand } {#1} },
    externalengine .code:n = { \__font_family_flat_append:nn { externalengine } {#1} },
    externalrendercommand .code:n = { \__font_family_flat_append:nn { externalrendercommand } {#1} },
    externalclusterwise .code:n = { \__font_family_flat_append:nn { externalclusterwise } {#1} },
  }

\cs_new_protected:Npn \__font_family_validate_mode:n #1 { }

\NewDocumentCommand{\DeclareUnicodeBlock}{mmm}
  { \__font_declare_unicode_block:nnn {#1} {#2} {#3} }

\NewDocumentCommand{\DeclareRangeKey}{mm}
  { \prop_gput:Nnn \g__font_range_key_blocks_prop {#1} {#2} }

\NewDocumentCommand{\DeclareRangeCodepointKey}{mmm}
  {
    \__font_declare_unicode_block:nnn {#1-codepoints} {#2} {#3}
    \prop_gput:Nnn \g__font_range_key_blocks_prop {#1} {#1-codepoints}
  }

\NewDocumentCommand{\DeclareRangeProfile}{mm}
  { \prop_gput:Nnn \g__font_range_profile_keys_prop {#1} {#2} }

\NewDocumentCommand{\FontRegisterFamily}{m}
  {
    \__font_family_reset:
    \keys_set:nn { font/family } {#1}

    \tl_if_blank:VTF \l__font_family_id_tl
      {
        \PackageError{font-family-registry}
          {Missing~id~field}
          {Set~id~=...~when~registering~a~font~family.}
      }
      { }

    \tl_if_blank:VTF \l__font_family_default_mode_tl
      { \tl_set:Nn \l__font_family_default_mode_tl { local } }
      { }

    \__font_family_validate_mode:n { \tl_use:N \l__font_family_default_mode_tl }

    \prop_put:NVV \g__font_family_default_prop \l__font_family_id_tl \l__font_family_default_mode_tl

    \tl_if_blank:VTF \l__font_family_local_tl
      {
        \tl_if_blank:VF \l__font_family_flat_decl_tl
          { \tl_set:NV \l__font_family_local_tl \l__font_family_flat_decl_tl }
      }
      { }

    \tl_if_blank:VTF \l__font_family_range_profile_tl
      { }
      { \prop_put:NVV \g__font_family_range_profile_prop \l__font_family_id_tl \l__font_family_range_profile_tl }

    \tl_if_blank:VTF \l__font_family_global_route_tl
      { \tl_set:Nn \l__font_family_global_route_tl { fontspec-range } }
      { }
    \prop_put:NVV \g__font_family_global_route_prop \l__font_family_id_tl \l__font_family_global_route_tl

    \tl_if_blank:VTF \l__font_family_local_tl
      { }
      { \prop_put:NVV \g__font_family_local_prop \l__font_family_id_tl \l__font_family_local_tl }

    \tl_if_blank:VTF \l__font_family_global_tl
      { }
      { \prop_put:NVV \g__font_family_global_prop \l__font_family_id_tl \l__font_family_global_tl }
  }

\cs_new_protected:Npn \__font_family_use_declaration:nnn #1#2#3
  {
    \prop_if_in:NnTF \g__font_family_loaded_prop { #1 / #2 }
      { }
      {
        \tl_set:Nx \l_tmpb_tl { scope = #2, familyid = #1, \exp_not:n {#3} }
        \exp_args:NV \FontDeclare \l_tmpb_tl
        \prop_put:Nnn \g__font_family_loaded_prop { #1 / #2 } { loaded }
      }
  }

\cs_generate_variant:Nn \__font_family_use_declaration:nnn { nnV }
\cs_generate_variant:Nn \__font_family_use_loader:nn { nV }

\cs_new_protected:Npn \__font_family_append_range_chain:nn #1#2
  {
    \prop_get:NnNTF \g__font_range_key_chain_prop {#2} \l_tmpa_tl
      {
        \exp_args:NV \clist_if_in:nnF \l_tmpa_tl {#1}
          {
            \tl_put_right:Nn \l_tmpa_tl { , #1 }
            \prop_gput:NnV \g__font_range_key_chain_prop {#2} \l_tmpa_tl
          }
      }
      { \prop_gput:Nnn \g__font_range_key_chain_prop {#2} {#1} }
  }

\cs_new_protected:Npn \__font_family_add_owned_range_key:nn #1#2
  {
    \tl_if_blank:nF {#2}
      {
        \__font_family_append_range_chain:nn {#1} {#2}
        \prop_if_in:NnTF \g__font_range_key_owner_prop {#2}
          { }
          {
            \prop_gput:Nnn \g__font_range_key_owner_prop {#2} {#1}
            \tl_if_blank:VTF \l__font_family_owned_range_keys_tl
              { \tl_set:Nn \l__font_family_owned_range_keys_tl {#2} }
              { \tl_put_right:Nn \l__font_family_owned_range_keys_tl { , #2 } }
            \prop_get:NnNT \g__font_range_key_blocks_prop {#2} \l_tmpa_tl
              {
                \tl_if_blank:VTF \l__font_family_owned_unicode_blocks_tl
                  { \tl_set:NV \l__font_family_owned_unicode_blocks_tl \l_tmpa_tl }
                  { \tl_put_right:Nx \l__font_family_owned_unicode_blocks_tl { , \exp_not:V \l_tmpa_tl } }
              }
          }
      }
  }

\cs_new_protected:Npn \__font_family_claim_profile:n #1
  {
    \tl_clear:N \l__font_family_owned_range_keys_tl
    \tl_clear:N \l__font_family_owned_unicode_blocks_tl
    \prop_get:NnNTF \g__font_family_range_profile_prop {#1} \l_tmpa_tl
      { }
      {
        \prop_if_in:NnTF \g__font_range_profile_keys_prop {#1}
          { \tl_set:Nn \l_tmpa_tl {#1} }
          { \tl_clear:N \l_tmpa_tl }
      }
    \tl_if_blank:VF \l_tmpa_tl
      {
        \exp_args:NV \clist_map_inline:nn \l_tmpa_tl
          {
            \prop_get:NnNTF \g__font_range_profile_keys_prop {##1} \l_tmpb_tl
              {
                \exp_args:NV \clist_map_inline:nn \l_tmpb_tl
                  { \__font_family_add_owned_range_key:nn {#1} {####1} }
              }
              { \__font_family_add_owned_range_key:nn {#1} {##1} }
          }
      }
  }

\cs_new_protected:Npn \__font_family_use_range_key_global:nn #1#2
  {
    \prop_if_in:NnF \g__font_range_key_owner_prop {#2}
      {
        \__font_family_append_range_chain:nn {#1} {#2}
        \prop_gput:Nnn \g__font_range_key_owner_prop {#2} {#1}
        \prop_get:NnNT \g__font_range_key_blocks_prop {#2} \l_tmpa_tl
          {
            \prop_if_in:NnF \g__font_family_loaded_prop { #1 / auto-range / #2 }
              {
                \prop_get:NnNTF \g__font_family_global_prop {#1} \l_tmpb_tl
                  {
                    \tl_set:Nx \l_tmpc_tl
                      {
                        scope = global, familyid = #1,
                        \exp_not:V \l_tmpb_tl
                        , unicodeblocks = { \exp_not:V \l_tmpa_tl }
                      }
                    \exp_args:NV \FontDeclare \l_tmpc_tl
                    \prop_put:Nnn \g__font_family_loaded_prop { #1 / auto-range / #2 } { loaded }
                  }
                  {
                    \PackageWarning{font-family-registry}
                      {Family~`#1'~cannot~provide~range~`#2'~because~it~has~no~global~declaration}
                  }
              }
          }
      }
  }

\cs_new_protected:Npn \__font_family_apply_auto_companions:n #1
  {
    \str_if_eq:nnT {#1} { tangut }
      {
        \__font_family_use_range_key_global:nn { shanggu } { cjk-punctuation }
      }
  }

\cs_new_protected:Npn \__font_family_use_auto_global:n #1
  {
    \prop_get:NnNTF \g__font_family_global_route_prop {#1} \l_tmpa_tl
      { }
      { \tl_set:Nn \l_tmpa_tl { fontspec-range } }
    \str_if_eq:VnTF \l_tmpa_tl { none }
      {
        \tl_clear:N \l__font_family_owned_range_keys_tl
        \tl_clear:N \l__font_family_owned_unicode_blocks_tl
      }
      {
        \__font_family_claim_profile:n {#1}
        \tl_if_blank:VF \l__font_family_owned_unicode_blocks_tl
          {
            \prop_if_in:NnF \g__font_family_loaded_prop { #1 / auto-global }
              {
                \prop_get:NnNTF \g__font_family_global_prop {#1} \l_tmpa_tl
                  {
                    \tl_set:Nx \l_tmpb_tl
                      {
                        scope = global, familyid = #1,
                        \exp_not:V \l_tmpa_tl
                        , unicodeblocks = { \exp_not:V \l__font_family_owned_unicode_blocks_tl }
                      }
                    \exp_args:NV \FontDeclare \l_tmpb_tl
                    \prop_put:Nnn \g__font_family_loaded_prop { #1 / auto-global } { loaded }
                  }
                  {
                    \prop_get:NnNT \g__font_family_local_prop {#1} \l_tmpa_tl
                      {
                        \tl_set:Nx \l_tmpb_tl
                          {
                            scope = global, familyid = #1,
                            \exp_not:V \l_tmpa_tl
                            , name = { #1 _global }
                            , unicodeblocks = { \exp_not:V \l__font_family_owned_unicode_blocks_tl }
                          }
                        \exp_args:NV \FontDeclare \l_tmpb_tl
                        \prop_put:Nnn \g__font_family_loaded_prop { #1 / auto-global } { loaded }
                      }
                  }
              }
          }
      }
  }

\cs_new_protected:Npn \__font_family_use_auto:n #1
  {
    \prop_if_in:NnTF \g__font_family_default_prop {#1}
      {
        \prop_if_in:NnT \g__font_family_local_prop {#1}
          {
            \prop_get:NnN \g__font_family_local_prop {#1} \l_tmpa_tl
            \__font_family_use_declaration:nnV {#1} { local } \l_tmpa_tl
          }
        \prop_get:NnN \g__font_family_default_prop {#1} \l_tmpa_tl
        \str_if_eq:VnT \l_tmpa_tl { global }
          {
            \prop_if_in:NnT \g__font_family_global_prop {#1}
              {
                \prop_get:NnN \g__font_family_global_prop {#1} \l_tmpb_tl
                \__font_family_use_declaration:nnV {#1} { global } \l_tmpb_tl
              }
          }
        \__font_family_use_auto_global:n {#1}
        \__font_family_apply_auto_companions:n {#1}
        \tl_if_blank:VT \l__font_family_owned_unicode_blocks_tl
          {
            \str_if_eq:VnF \l_tmpa_tl { global }
              {
                \prop_if_in:NnT \g__font_family_global_prop {#1}
                  {
                    \prop_get:NnN \g__font_family_global_prop {#1} \l_tmpb_tl
                    \__font_family_use_declaration:nnV {#1} { global } \l_tmpb_tl
                  }
              }
          }
      }
      {
        \PackageError{font-family-registry}
          {Unknown~font~family~id}
          {Register~family~`#1'~with~\string\FontRegisterFamily\ first.}
      }
  }

\cs_new_protected:Npn \__font_family_use_loader:nn #1#2
  {
    \str_if_eq:nnTF {#2} { local }
      {
        \prop_if_in:NnTF \g__font_family_local_prop {#1}
          {
            \prop_get:NnN \g__font_family_local_prop {#1} \l_tmpa_tl
            \__font_family_use_declaration:nnV {#1} { local } \l_tmpa_tl
          }
          {
            \PackageError{font-family-registry}
              {Unknown~font~family~mode}
              {Family~`#1'~does~not~provide~mode~`local'.}
          }
      }
      {
        \str_if_eq:nnTF {#2} { global }
          {
            \prop_if_in:NnTF \g__font_family_global_prop {#1}
              {
                \prop_get:NnN \g__font_family_global_prop {#1} \l_tmpa_tl
                \__font_family_use_declaration:nnV {#1} { global } \l_tmpa_tl
              }
              {
                \prop_if_in:NnTF \g__font_family_default_prop {#1}
                  {
                    \__font_family_use_auto_global:n {#1}
                    \tl_if_blank:VT \l__font_family_owned_unicode_blocks_tl
                      {
                        \PackageError{font-family-registry}
                          {Font~family~has~no~global~mode}
                          {Family~`#1'~does~not~provide~a~global~block~or~rangeprofile.}
                      }
                  }
                  {
                    \PackageError{font-family-registry}
                      {Unknown~font~family~id}
                      {Register~family~`#1'~with~\string\FontRegisterFamily\ first.}
                  }
              }
          }
          {
            \PackageError{font-family-registry}
              {Unknown~font~family~mode}
              {Use~local~or~global.}
          }
      }
  }

\cs_new_protected:Npn \__font_family_use_default:n #1
  { \__font_family_use_auto:n {#1} }

\cs_new_protected:Npn \NextFontFamilyLoadedTF #1#2#3
  {
    \prop_if_in:NnTF \g__font_family_loaded_prop { #1 / local }
      {#2}
      {
        \prop_if_in:NnTF \g__font_family_loaded_prop { #1 / global }
          {#2}
          {
            \prop_if_in:NnTF \g__font_family_loaded_prop { #1 / auto-global }
              {#2}
              {#3}
          }
      }
  }

\NewDocumentCommand{\UseFont}{m O{}}
  {
    \tl_if_blank:nTF {#2}
      { \__font_family_use_default:n {#1} }
      { \__font_family_use_loader:nn {#1} {#2} }
  }

\NewDocumentCommand{\UseFonts}{m O{}}
  { \clist_map_inline:nn {#1} { \UseFont{##1}[#2] } }

\ExplSyntaxOff