local function auto(event, opts)
  a.nvim_create_autocmd(event, opts)
end

a.nvim_create_augroup('bufcheck', {clear = true})

auto('TextYankPost', { -- highlight yanks
  group = 'bufcheck',
  pattern = '*',
  desc = 'Highlight on yank.',
  callback = function()
    vim.highlight.on_yank{ timeout = 250 }
  end
})

auto('FileType', { -- start git messages in insert mode
  group = 'bufcheck',
  pattern = { 'gitcommit', 'gitrebase', },
  desc = 'Start git messages in insert mode.',
  command = 'startinsert | 1'
})

auto('BufRead', { -- return to last place
  pattern = '*',
  command = [[call setpos(".", getpos("'\""))]],
  desc = 'Return to the last place the buffer was closed in.',
})

auto('TermOpen', { -- start terminal in insert mode
  group    = 'bufcheck',
  pattern  = '*',
  desc     = 'Start terminal in insert mode.',
  callback = function()
    vim.cmd('startinsert | set winfixheight')
    o.winfixheight = true
    o.cmdheight = 0
  end
})

auto('TermClose', { -- close terminal buffers after shell dies
  group    = 'bufcheck',
  pattern  = 'term://*',
  desc     = 'Close terminal after shell dies.',
  callback = function()
    vim.cmd('call nvim_input("<CR>")')
    o.cmdheight = 1
  end
})

auto('InsertEnter', { -- toggle things when entering insert mode
  group = 'bufcheck',
  desc  = 'Turn things on insert mode.',
  callback = function()
    o.colorcolumn = { 80 }
  end
})

auto('InsertLeave', { -- toggle things when exiting insert mode
  group = 'bufcheck',
  desc  = 'Turn things off insert mode.',
  callback = function()
    o.colorcolumn = { 0 }
  end
})

auto('BufWritePre', { -- make dirs when they don't exist
  pattern = '*',
  group = vim.api.nvim_create_augroup('auto_create_dir', { clear = true }),
  desc = 'Basically mkdir -p.',
  callback = function(ctx)
    local dir = vim.fn.fnamemodify(ctx.file, ':p:h')
    vim.fn.mkdir(dir, 'p')
  end
})