patch 9.1.0354: runtime(uci): No support for uci file types

Problem:  runtime(uci): No support for uci file types
          (Wu, Zhenyu)
Solution: include basic uci ftplugin and syntax plugins
          (Colin Caine)

closes: #14575

Co-authored-by: Wu, Zhenyu <wuzhenyu@ustc.edu>
Signed-off-by: Colin Caine <complaints@cmcaine.co.uk>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/autoload/dist/ft.vim b/runtime/autoload/dist/ft.vim
index 05f1611..4e7d517 100644
--- a/runtime/autoload/dist/ft.vim
+++ b/runtime/autoload/dist/ft.vim
@@ -1298,5 +1298,21 @@
   endif
 enddef
 
+export def Detect_UCI_statements(): bool
+  # Match a config or package statement at the start of the line.
+  const config_or_package_statement = '^\s*\(\(c\|config\)\|\(p\|package\)\)\s\+\S'
+  # Match a line that is either all blank or blank followed by a comment
+  const comment_or_blank = '^\s*\(#.*\)\?$'
+
+  # Return true iff the file has a config or package statement near the
+  # top of the file and all preceding lines were comments or blank.
+  return getline(1) =~# config_or_package_statement
+  \   || getline(1) =~# comment_or_blank
+  \      && (   getline(2) =~# config_or_package_statement
+  \          || getline(2) =~# comment_or_blank
+  \             && getline(3) =~# config_or_package_statement
+  \         )
+enddef
+
 # Uncomment this line to check for compilation errors early
 # defcompile
diff --git a/runtime/filetype.vim b/runtime/filetype.vim
index 4a877f7..c7fc331 100644
--- a/runtime/filetype.vim
+++ b/runtime/filetype.vim
@@ -3030,6 +3030,12 @@
 " Universal Scene Description
 au BufNewFile,BufRead *.usda,*.usd		setf usd
 
+" UCI
+" UCI files are normally in /etc/config, but that might be mounted over sshfs or similar, so we match more loosely.
+" There was some concern[1] that this pattern would match too much, so now we check the file content as well.
+" [1]: https://github.com/vim/vim/pull/14385#discussion_r1558878741
+au BufNewFile,BufRead */etc/config/*		if dist#ft#Detect_UCI_statements() | call s:StarSetf('uci') | endif
+
 " VHDL
 au BufNewFile,BufRead *.vhdl_[0-9]*		call s:StarSetf('vhdl')
 
diff --git a/runtime/ftplugin/uci.vim b/runtime/ftplugin/uci.vim
new file mode 100644
index 0000000..984dab6
--- /dev/null
+++ b/runtime/ftplugin/uci.vim
@@ -0,0 +1,21 @@
+" Vim ftplugin file
+" Language:	OpenWrt Unified Configuration Interface
+" Maintainer:	Colin Caine <complaints@cmcaine.co.uk>
+" Upstream:	https://github.com/cmcaine/vim-uci
+" Last Change:	2024 Apr 17
+"
+" For more information on uci, see https://openwrt.org/docs/guide-user/base-system/uci
+
+if exists("b:did_ftplugin")
+  finish
+endif
+let b:did_ftplugin = 1
+
+" UCI files are indented with tabs.
+setl noexpandtab
+setl shiftwidth=0
+setl softtabstop=0
+
+setl commentstring=#\ %s
+
+let b:undo_ftplugin = "setlocal et< cms< sts< sw<"
diff --git a/runtime/syntax/uci.vim b/runtime/syntax/uci.vim
new file mode 100644
index 0000000..fdf5bfd
--- /dev/null
+++ b/runtime/syntax/uci.vim
@@ -0,0 +1,33 @@
+" Vim syntax file
+" Language:	OpenWrt Unified Configuration Interface
+" Maintainer:	Colin Caine <complaints@cmcaine.co.uk>
+" Upstream:	https://github.com/cmcaine/vim-uci
+" Last Change:	2021 Sep 19
+"
+" For more information on uci, see https://openwrt.org/docs/guide-user/base-system/uci
+
+if exists("b:current_syntax")
+    finish
+endif
+
+" Fancy zero-width non-capturing look-behind to see what the last word was.
+" Would be really nice if there was some less obscure or more efficient way to
+" do this.
+syntax match uciOptionName '\%(\%(option\|list\)\s\+\)\@<=\S*'
+syntax match uciConfigName '\%(\%(package\|config\)\s\+\)\@<=\S*'
+syntax keyword uciConfigDec package config nextgroup=uciConfigName skipwhite
+syntax keyword uciOptionType option list nextgroup=uciOptionName skipwhite
+
+" Standard matches.
+syntax match uciComment "#.*$"
+syntax region uciString start=+"+ end=+"+ skip=+\\"+
+syntax region uciString start=+'+ end=+'+ skip=+\\'+
+
+highlight default link uciConfigName Identifier
+highlight default link uciOptionName Constant
+highlight default link uciConfigDec Statement
+highlight default link uciOptionType Type
+highlight default link uciComment Comment
+highlight default link uciString Normal
+
+let b:current_syntax = "uci"