map = vim.api.nvim_set_keymap

function escape_keycode(keycode)
    return vim.api.nvim_replace_termcodes(keycode, true, true, true)
end

local function check_back_space()
  local col = vim.fn.col(".") - 1
  return col <= 0 or vim.fn.getline("."):sub(col, col):match("%s")
end

function tab_completion()
  if vim.fn.pumvisible() > 0 then
    return escape_keycode("<C-n>")
  end

  if check_back_space() then
    return escape_keycode("<TAB>")
  end

  return vim.fn["coc#refresh"]()
end

function shift_tab_completion()
    if vim.fn.pumvisible() > 0 then
        return escape_keycode("<C-p>")
    else
        return escape_keycode("<C-h>")
    end
end

function cr_completion()
    if vim.fn.pumvisible() > 0 then
        return vim.fn["coc#_select_confirm"]()
    else
        return escape_keycode("<CR>")
    end
end

-- Getting stuck in ~~vim~~ terminal
map("t", "<Esc>", "<C-\\><C-n>", {})
map("n", "fzf", ":FZF<CR>", { silent = true })

-- Quick cursor movement
map("n", "<C-Down>", "5j", { noremap = true })
map("n", "<C-Up>", "5k", { noremap = true })

-- Quick pasting/yoinking to system register
map("n", "+y", "\"+y", { noremap = true })
map("n", "+p", "\"+p", { noremap = true })
map("n", "+d", "\"+d", { noremap = true })

map("n", "*y", "\"*y", { noremap = true })
map("n", "*p", "\"*p", { noremap = true })
map("n", "*d", "\"*d", { noremap = true })

map("i", "<TAB>", "v:lua.tab_completion()", { expr = true })
map("i", "<S-TAB>", "v:lua.shift_tab_completion()", { expr = true })
map("i", "<CR>", "v:lua.cr_completion()", { expr = true })

-- symbol renaming
map("n", "-n", "<Plug>(coc-rename)", { silent = true })
-- apply AutoFix to problem on current line
map("n", "-f", "<Plug>(coc-fix-current)", { silent = true })
-- open action dialog
map("n", "-a", ":CocAction<CR>", { silent = true })

-- GoTo code navigation.
map("n", "gd", "<Plug>(coc-definition)", { silent = true })
map("n", "gy", "<Plug>(coc-type-definition)", { silent = true })
map("n", "gi", "<Plug>(coc-implementation)", { silent = true })
map("n", "gr", "<Plug>(coc-references)", { silent = true })

-- Use K to show documentation in preview window.
map("n", "K", ":call CocActionAsync(\'doHover\')<CR>", { silent = true })

-- use space o to show symbols
map("n", "<space>o", ":CocList -I symbols<CR>", { silent = true })

-- format code
map("n", "-r", ":call CocActionAsync(\'format\')<CR>", { silent = true })

-- Use <c-space> to trigger completion.
map("i", "<c-space>", "coc#refresh()", { silent = true, expr = true })

-- Use -d to jump to next diagnostic
map("n", "-d", "<Plug>(coc-diagnostic-next)", { silent = true })

-- Use -o to show outline
map("n", "-o", ":CocList outline<CR>", { silent = true })