refactor: rewrite python provider in lua

runtime/autoload/provider/python3.vim

@@ -1,45 +1,15 @@
-" The Python3 provider uses a Python3 host to emulate an environment for running
-" python3 plugins. :help provider
-"
-" Associating the plugin with the Python3 host is the first step because
-" plugins will be passed as command-line arguments
-
 if exists('g:loaded_python3_provider')
   finish
 endif
-let [s:prog, s:err] = provider#pythonx#Detect(3)
-let g:loaded_python3_provider = empty(s:prog) ? 1 : 2
-
-function! provider#python3#Prog() abort
-  return s:prog
-endfunction
-
-function! provider#python3#Error() abort
-  return s:err
-endfunction
-
-" The Python3 provider plugin will run in a separate instance of the Python3
-" host.
-call remote#host#RegisterClone('legacy-python3-provider', 'python3')
-call remote#host#RegisterPlugin('legacy-python3-provider', 'script_host.py', [])
 
 function! provider#python3#Call(method, args) abort
-  if s:err != ''
-    return
-  endif
-  if !exists('s:host')
-    let s:rpcrequest = function('rpcrequest')
-
-    " Ensure that we can load the Python3 host before bootstrapping
-    try
-      let s:host = remote#host#Require('legacy-python3-provider')
-    catch
-      let s:err = v:exception
-      echohl WarningMsg
-      echomsg v:exception
-      echohl None
-      return
-    endtry
-  endif
-  return call(s:rpcrequest, insert(insert(a:args, 'python_'.a:method), s:host))
+  return v:lua.require'vim.provider.python'.call(a:method, a:args)
 endfunction
+
+function! provider#python3#Require(host) abort
+  return v:lua.require'vim.provider.python'.require(a:host)
+endfunction
+
+let s:prog = v:lua.require'vim.provider.python'.detect_by_module('neovim')
+let g:loaded_python3_provider = empty(s:prog) ? 1 : 2
+call v:lua.require'vim.provider.python'.start()