local fn = vim.fn
local api = vim.api

local utils = require("utils")

-- Display a message when the current file is not in utf-8 format.
-- Note that we need to use `unsilent` command here because of this issue:
-- https://github.com/vim/vim/issues/4379
api.nvim_create_autocmd({ "BufRead" }, {
  pattern = "*",
  group = api.nvim_create_augroup("non_utf8_file", { clear = true }),
  callback = function()
    if vim.bo.fileencoding ~= "utf-8" then
      vim.notify("File not in UTF-8 format!", vim.log.levels.WARN, { title = "nvim-config" })
    end
  end,
})

-- highlight yanked region, see `:h lua-highlight`
local yank_group = api.nvim_create_augroup("highlight_yank", { clear = true })
api.nvim_create_autocmd({ "TextYankPost" }, {
  pattern = "*",
  group = yank_group,
  callback = function()
    vim.highlight.on_yank { higroup = "YankColor", timeout = 300 }
  end,
})

api.nvim_create_autocmd({ "CursorMoved" }, {
  pattern = "*",
  group = yank_group,
  callback = function()
    vim.g.current_cursor_pos = vim.fn.getcurpos()
  end,
})

api.nvim_create_autocmd("TextYankPost", {
  pattern = "*",
  group = yank_group,
  callback = function(ev)
    if vim.v.event.operator == 'y' then
      vim.fn.setpos('.', vim.g.current_cursor_pos)
    end
  end,
})

-- Auto-create dir when saving a file, in case some intermediate directory does not exist
api.nvim_create_autocmd({ "BufWritePre" }, {
  pattern = "*",
  group = api.nvim_create_augroup("auto_create_dir", { clear = true }),
  callback = function(ctx)
    local dir = fn.fnamemodify(ctx.file, ":p:h")
    utils.may_create_dir(dir)
  end,
})

-- Automatically reload the file if it is changed outside of Nvim, see https://unix.stackexchange.com/a/383044/221410.
-- It seems that `checktime` does not work in command line. We need to check if we are in command
-- line before executing this command, see also https://vi.stackexchange.com/a/20397/15292 .
api.nvim_create_augroup("auto_read", { clear = true })

api.nvim_create_autocmd({ "FileChangedShellPost" }, {
  pattern = "*",
  group = "auto_read",
  callback = function()
    vim.notify("File changed on disk. Buffer reloaded!", vim.log.levels.WARN, { title = "nvim-config" })
  end,
})

api.nvim_create_autocmd({ "FocusGained", "CursorHold" }, {
  pattern = "*",
  group = "auto_read",
  callback = function()
    if fn.getcmdwintype() == "" then
      vim.cmd("checktime")
    end
  end,
})

-- Resize all windows when we resize the terminal
api.nvim_create_autocmd("VimResized", {
  group = api.nvim_create_augroup("win_autoresize", { clear = true }),
  desc = "autoresize windows on resizing operation",
  command = "wincmd =",
})

local function open_nvim_tree(data)
  -- check if buffer is a directory
  local directory = vim.fn.isdirectory(data.file) == 1

  if not directory then
    return
  end

  -- create a new, empty buffer
  vim.cmd.enew()

  -- wipe the directory buffer
  vim.cmd.bw(data.buf)

  -- open the tree
  require("nvim-tree.api").tree.open()
end

vim.api.nvim_create_autocmd({ "VimEnter" }, { callback = open_nvim_tree })