nvim-config/lua/user/lsp/handlers.lua

local M = {}

local status_cmp_ok, cmp_nvim_lsp = pcall(require, "cmp_nvim_lsp")
if not status_cmp_ok then
	return
end

M.capabilities = vim.lsp.protocol.make_client_capabilities()
M.capabilities.textDocument.completion.completionItem.snippetSupport = true
M.capabilities = cmp_nvim_lsp.default_capabilities(M.capabilities)
M.capabilities.offsetEncoding = 'utf-16'

M.setup = function()
	local signs = {
		{ name = "DiagnosticSignError", text = "" },
		{ name = "DiagnosticSignWarn", text = "" },
		{ name = "DiagnosticSignHint", text = "" },
		{ name = "DiagnosticSignInfo", text = "" },
	}

	for _, sign in ipairs(signs) do
		vim.fn.sign_define(sign.name, { texthl = sign.name, text = sign.text, numhl = "" })
	end

	local config = {
		virtual_text = false, -- disable virtual text
		signs = {
			active = signs, -- show signs
		},
		update_in_insert = true,
		underline = true,
		severity_sort = true,
		float = {
			focusable = true,
			style = "minimal",
			border = "rounded",
			source = "always",
			header = "",
			prefix = "",
		},
	}

	vim.diagnostic.config(config)

	vim.lsp.handlers["textDocument/hover"] = vim.lsp.with(vim.lsp.handlers.hover, {
		border = "rounded",
	})

	vim.lsp.handlers["textDocument/signatureHelp"] = vim.lsp.with(vim.lsp.handlers.signature_help, {
		border = "rounded",
	})
end

local function lsp_keymaps(bufnr)
	local opts = { noremap = true, silent = true }
	local keymap = vim.api.nvim_buf_set_keymap
	keymap(bufnr, "n", "gD", "<cmd>lua vim.lsp.buf.declaration()<CR>", opts)
	keymap(bufnr, "n", "gd", "<cmd>lua vim.lsp.buf.definition()<CR>", opts)
	keymap(bufnr, "n", "K", "<cmd>lua vim.lsp.buf.hover()<CR>", opts)
	keymap(bufnr, "n", "gI", "<cmd>lua vim.lsp.buf.implementation()<CR>", opts)
	keymap(bufnr, "n", "gr", "<cmd>lua vim.lsp.buf.references()<CR>", opts)
	keymap(bufnr, "n", "gl", "<cmd>lua vim.diagnostic.open_float()<CR>", opts)
	keymap(bufnr, "n", "<leader>lf", "<cmd>lua vim.lsp.buf.format{ async = true }<cr>", opts)
	keymap(bufnr, "n", "<leader>li", "<cmd>LspInfo<cr>", opts)
	keymap(bufnr, "n", "<leader>lI", "<cmd>LspInstallInfo<cr>", opts)
	keymap(bufnr, "n", "<leader>la", "<cmd>lua vim.lsp.buf.code_action()<cr>", opts)
	keymap(bufnr, "n", "<leader>lj", "<cmd>lua vim.diagnostic.goto_next({buffer=0})<cr>", opts)
	keymap(bufnr, "n", "<leader>lk", "<cmd>lua vim.diagnostic.goto_prev({buffer=0})<cr>", opts)
	keymap(bufnr, "n", "<leader>lr", "<cmd>lua vim.lsp.buf.rename()<cr>", opts)
	keymap(bufnr, "n", "<leader>ls", "<cmd>lua vim.lsp.buf.signature_help()<CR>", opts)
	keymap(bufnr, "n", "<leader>lq", "<cmd>lua vim.diagnostic.setloclist()<CR>", opts)
end

M.on_attach = function(client, bufnr)

  if client.name == "omnisharp" then
    client.server_capabilities.semanticTokensProvider = {
      full = vim.empty_dict(),
      legend = {
        tokenModifiers = { "static_symbol" },
        tokenTypes = {
          "comment",
          "excluded_code",
          "identifier",
          "keyword",
          "keyword_control",
          "number",
          "operator",
          "operator_overloaded",
          "preprocessor_keyword",
          "string",
          "whitespace",
          "text",
          "static_symbol",
          "preprocessor_text",
          "punctuation",
          "string_verbatim",
          "string_escape_character",
          "class_name",
          "delegate_name",
          "enum_name",
          "interface_name",
          "module_name",
          "struct_name",
          "type_parameter_name",
          "field_name",
          "enum_member_name",
          "constant_name",
          "local_name",
          "parameter_name",
          "method_name",
          "extension_method_name",
          "property_name",
          "event_name",
          "namespace_name",
          "label_name",
          "xml_doc_comment_attribute_name",
          "xml_doc_comment_attribute_quotes",
          "xml_doc_comment_attribute_value",
          "xml_doc_comment_cdata_section",
          "xml_doc_comment_comment",
          "xml_doc_comment_delimiter",
          "xml_doc_comment_entity_reference",
          "xml_doc_comment_name",
          "xml_doc_comment_processing_instruction",
          "xml_doc_comment_text",
          "xml_literal_attribute_name",
          "xml_literal_attribute_quotes",
          "xml_literal_attribute_value",
          "xml_literal_cdata_section",
          "xml_literal_comment",
          "xml_literal_delimiter",
          "xml_literal_embedded_expression",
          "xml_literal_entity_reference",
          "xml_literal_name",
          "xml_literal_processing_instruction",
          "xml_literal_text",
          "regex_comment",
          "regex_character_class",
          "regex_anchor",
          "regex_quantifier",
          "regex_grouping",
          "regex_alternation",
          "regex_text",
          "regex_self_escaped_character",
          "regex_other_escape",
        },
      },
      range = true,
    }
  end

	lsp_keymaps(bufnr)
	local status_ok, illuminate = pcall(require, "illuminate")
	if not status_ok then
		return
	end
	illuminate.on_attach(client)
end

return M