" vim-im-switch-select.vim - 智能记忆输入法状态 (使用 im-select)
" Author:       Gavin Chan
" Modified by:  codefalling, enhanced with smart IM state memory
" Version:      2.0.0
" Description:  记住退出 Insert 模式时的输入法状态，下次进入时自动恢复
"               使用 im-select 而不是 fcitx-remote 切换输入法
" ---------------------------------------------------------------------
" Load Once:
if exists('g:imselect_loaded')
  finish
endif

if &ttimeoutlen <= 0 || &ttimeoutlen > 50
    set ttimeoutlen=50
endif

if (has("win32") || has("win95") || has("win64") || has("win16"))
  " Windows 下不要载入
  finish
endif
if exists('$SSH_TTY')
  finish
endif
if !executable("im-select")
  finish
endif
let s:imselect_cmd = exepath('im-select')
let s:keepcpo = &cpo
let g:imselect_loaded = 1
set cpo&vim

" ---------------------------------------------------------------------
" 全局变量：记住上次 Insert 模式的输入法名称
let g:imselect_last_insert_im_name = ''

" 英文和中文输入法的 ID（可以通过 im-select 获取）
if !exists('g:imselect_english_im')
    let g:imselect_english_im = 'com.apple.keylayout.ABC'
endif

if !exists('g:imselect_chinese_im')
    let g:imselect_chinese_im = 'com.apple.inputmethod.SCIM.ITABC'
endif

" ---------------------------------------------------------------------
" Functions:

function! IMSelectCurrentIM() abort
  return substitute(system(shellescape(s:imselect_cmd) . ' 2>/dev/null'), '[\r\n]', '', 'g')
endfunction

function! IMSelectSwitch(im) abort
  if has('job')
    silent! call job_start([s:imselect_cmd, a:im], {'out_io': 'null', 'err_io': 'null'})
  else
    silent! call system(shellescape(s:imselect_cmd) . ' ' . shellescape(a:im) . ' >/dev/null 2>&1 &')
  endif
endfunction

function! IMSelectStart() abort
  call IMSelectSwitch(g:imselect_english_im)
endfunction

function! IMSelectEnsureTarget(timer) abort
  if g:imselect_last_insert_im_name != ''
    call IMSelectSwitch(g:imselect_last_insert_im_name)
  endif
endfunction

" 离开 Insert 模式前：保存当前输入法名称
function! IMSelectRemember() abort
  let current_im = IMSelectCurrentIM()
  if current_im != ''
    let g:imselect_last_insert_im_name = current_im
  endif
endfunction

" 离开 Insert 模式：切换到英文
function! IMSelect2en() abort
  call IMSelectSwitch(g:imselect_english_im)
endfunction

" 恢复 Insert 模式输入法
function! IMSelectRestore(timer) abort
  if g:imselect_last_insert_im_name == ''
    let g:imselect_last_insert_im_name = g:imselect_chinese_im
  endif
  call IMSelectSwitch(g:imselect_last_insert_im_name)
  call timer_start(200, function('IMSelectEnsureTarget'))
endfunction

" 进入 Insert 模式：延迟恢复保存的输入法
function! IMSelect2zh() abort
  call timer_start(80, function('IMSelectRestore'))
endfunction
" ---------------------------------------------------------------------
" Autocmds:

" 绑定自动命令
function! BindIMSelectAu()
  augroup IMSelect
   autocmd!
   " 离开 Insert 模式前：先保存输入法状态
   autocmd InsertLeavePre * call IMSelectRemember()
   " 离开 Insert 模式：切换到英文
   autocmd InsertLeave * call IMSelect2en()
   " 进入 Insert 模式：恢复上次的输入法状态
   autocmd InsertEnter * call IMSelect2zh()
   " Vim 启动后：切换到英文
   autocmd VimEnter * call timer_start(100, {-> IMSelectStart()})
  augroup END
endfunction

function! UnBindIMSelectAu()
  augroup IMSelect
   autocmd!
  augroup END
endfunction

call BindIMSelectAu()

" 多光标支持：在选择多个光标前后的处理
function! IMSelect_multiple_cursors_before()
  call UnBindIMSelectAu()
endfunction

function! IMSelect_multiple_cursors_after()
  call IMSelect2en()
  call BindIMSelectAu()
endfunction

" ---------------------------------------------------------------------
" Restoration And Modelines:
let &cpo=s:keepcpo
unlet s:keepcpo

let g:imselect_loaded = 1

" vim:fdm=expr:fde=getline(v\:lnum-1)=~'\\v"\\s*-{20,}'?'>1'\:1