# http://lua.org
# ‾‾‾‾‾‾‾‾‾‾‾‾‾‾

# require commenting.kak

# Detection
# ‾‾‾‾‾‾‾‾‾

hook global BufSetOption mimetype=text/x-lua %{
    set buffer filetype lua
}

hook global BufCreate .*[.](lua) %{
    set buffer mimetype text/x-lua
}

# Highlighters
# ‾‾‾‾‾‾‾‾‾‾‾‾

addhl -group / regions -default code lua \
    string  '"' (?<!\\)(\\\\)*"       '' \
    string  "'" (?<!\\)(\\\\)*'       '' \
    comment '--' '$'                  '' \
    comment '\Q--[[' ']]'             '' \

addhl -group /lua/string fill string

addhl -group /lua/comment fill comment

addhl -group /lua/code regex \<(and|break|do|else|elseif|end|false|for|function|goto|if|in|local|nil|not|or|repeat|return|then|true|until|while)\> 0:keyword

# Commands
# ‾‾‾‾‾‾‾‾

def -hidden _lua_filter_around_selections %{
    eval -draft -itersel %{
        exec <a-x>
        # remove trailing white spaces
        try %{ exec -draft s \h + $ <ret> d }
    }
}

def -hidden _lua_indent_on_char %{
    eval -draft -itersel %{
        # align end structure to start
        try %{ exec -draft <a-x> <a-k> ^ \h * end $ <ret> <a-\;> <a-?> ^ \h * (for|function|if|while) <ret> s \A | \Z <ret> \' <a-&> }
        # align _else_ statements to previous _if_
        try %{ exec -draft <a-x> <a-k> ^ \h * else (if) ? $ <ret> <a-\;> <a-?> ^ \h * if <ret> s \A | \Z <ret> \' <a-&> }
    }
}

def -hidden _lua_indent_on_new_line %{
    eval -draft -itersel %{
        # preserve previous line indent
        try %{ exec -draft K <a-&> }
        # filter previous line
        try %{ exec -draft k : _lua_filter_around_selections <ret> }
        # copy -- comment prefix and following white spaces
        try %{ exec -draft k x s ^ \h * \K -- \h * <ret> y j p }
        # indent after start structure
        try %{ exec -draft k x <a-k> ^ \h * (else|elseif|for|function|if|while) \b <ret> j <a-gt> }
        # wisely add end structure
        eval -save-regs x %{
            try %{ exec -draft k x s ^ \h + <ret> \" x y } catch %{ reg x '' }
            try %{ exec -draft k x <a-k> ^ <c-r> x (for|function|if|while) <ret> j <a-a> i X <a-\;> K <a-K> ^ <c-r> x (for|function|if|while) . * \n <c-r> x end $ <ret> j x y p j a end <esc> <a-lt> }
        }
    }
}

# Initialization
# ‾‾‾‾‾‾‾‾‾‾‾‾‾‾

hook global WinSetOption filetype=lua %{
    addhl ref lua

    hook window InsertEnd  .* -group lua-hooks  _lua_filter_around_selections
    hook window InsertChar .* -group lua-indent _lua_indent_on_char
    hook window InsertChar \n -group lua-indent _lua_indent_on_new_line

    set window comment_line_chars '--'
    set window comment_selection_chars '\Q--[[:]]'
}

hook global WinSetOption filetype=(?!lua).* %{
    rmhl lua
    rmhooks window lua-indent
    rmhooks window lua-hooks
}