if vim.g.loaded_guicursor then
  return
end

vim.g.loaded_guicursor = true

local mode_lookup = {
  normal = "n-v",
  insert = "i-c-ci-ve",
  replace = "r-cr",
  operator = "o",
  showmatch = "sm",
}

local type_lookup = {
  block = "block",
  vertical = "ver",
  horizontal = "hor",
}

local function validate(mode, opts)
  vim.validate("mode", mode, function(v)
    return vim.tbl_contains({ "normal", "insert", "replace", "operator", "showmatch" }, v)
  end, "valid mode")
  vim.validate("opts", opts, function(v)
    vim.validate("type", v.type, function(t)
      return vim.tbl_contains({ "block", "vertical", "horizontal" }, t)
    end, "valid type")
    if v.type ~= "block" then
      vim.validate("size", v.size, function(s)
        return type(s) == "number"
      end, "valid size with type ~= block")
    end

    vim.validate("animate", v.animate, function(anim)
      vim.validate("wait", anim.wait, "number")
      vim.validate("on", anim.on, "number")
      vim.validate("off", anim.off, "number")
      return true
    end, true, "valid animation")

    return true
  end, "valid opts")
end

vim.once(function()
  if not vim.g.guicursor_config or vim.tbl_isempty(vim.g.guicursor_config) then
    return
  end

  local guicursorset = vim
    .iter(pairs(vim.g.guicursor_config))
    :map(function(mode, opts)
      validate(mode, opts)

      local s = string.format(
        "%s:%s",
        mode_lookup[mode],
        opts.type ~= "block" and string.format("%s%d", type_lookup[opts.type], opts.size) or type_lookup[opts.type]
      )

      if opts.animate then
        local anim = opts.animate
        local anim_str = string.format("blinkwait%d-blinkon%d-blinkoff%d", anim.wait, anim.on, anim.off)
        s = s .. "-" .. anim_str
      end

      return s
    end)
    :totable()

  vim.opt.guicursor = table.concat(guicursorset, ",") .. ",a:Cursor/lCursor"
end)