nvim/lua/my-lsp.lua

local nvim_lsp = require('lspconfig')

-- enable snippet support
local capabilities = vim.lsp.protocol.make_client_capabilities()
capabilities.textDocument.completion.completionItem.snippetSupport = true
capabilities.textDocument.completion.completionItem.resolveSupport = {
  properties = {
    'documentation',
    'detail',
    'additionalTextEdits',
  }
}

-- Use an on_attach function to only map the following keys
-- after the language server attaches to the current buffer
local on_attach = function(client, bufnr)
	local function buf_set_keymap(...) vim.api.nvim_buf_set_keymap(bufnr, ...) end
	local function buf_set_option(...) vim.api.nvim_buf_set_option(bufnr, ...) end

	--Enable completion triggered by <c-x><c-o>
	buf_set_option('omnifunc', 'v:lua.vim.lsp.omnifunc')

	-- Mappings.
	local opts = { noremap=true, silent=true }

	-- See `:help vim.lsp.*` for documentation on any of the below functions
	buf_set_keymap('n', 'gD', '<Cmd>lua vim.lsp.buf.declaration()<CR>', opts)
	buf_set_keymap('n', 'gd', '<Cmd>lua vim.lsp.buf.definition()<CR>', opts)
	buf_set_keymap('n', 'K', '<Cmd>lua vim.lsp.buf.hover()<CR>', opts)
	buf_set_keymap('v', 'K', '<Cmd>lua vim.lsp.buf.hover()<CR>', opts)
	buf_set_keymap('n', 'gi', '<cmd>lua vim.lsp.buf.implementation()<CR>', opts)
	buf_set_keymap('n', '<C-k>', '<cmd>lua vim.lsp.buf.signature_help()<CR>', opts)
	buf_set_keymap('n', '<Leader>D', '<cmd>lua vim.lsp.buf.type_definition()<CR>', opts)
	buf_set_keymap('n', '<Leader>rn', '<cmd>lua vim.lsp.buf.rename()<CR>', opts)
	buf_set_keymap('n', '<M-a>', '<cmd>lua vim.lsp.buf.code_action()<CR>', opts)
	buf_set_keymap('n', 'gr', '<cmd>lua vim.lsp.buf.references()<CR>', opts)
	buf_set_keymap('n', '<M-e>', '<cmd>lua vim.diagnostic.open_float()<CR>', opts)
	buf_set_keymap('n', '[d', '<cmd>lua vim.lsp.diagnostic.goto_prev()<CR>', opts)
	buf_set_keymap('n', ']d', '<cmd>lua vim.lsp.diagnostic.goto_next()<CR>', opts)
	buf_set_keymap('n', '<M-q>', '<cmd>lua vim.lsp.diagnostic.set_loclist()<CR>', opts)
	buf_set_keymap("n", "<Leader>f", "<cmd>lua vim.lsp.buf.formatting()<CR>", opts)
	--require'completion'.on_attach(client, bufnr)
end


require'lspinstall'.setup() -- important

local servers = require'lspinstall'.installed_servers()
for _, server in pairs(servers) do
  require'lspconfig'[server].setup{
    on_attach = on_attach,
    capabilities = capabilities,
  }
end


metals_config = require("metals").bare_config()
metals_config.init_options.statusBarProvider = "on"
metals_config.settings = { showImplicitArguments = true }
metals_config.on_attach = on_attach

vim.cmd [[augroup lsp]]
vim.cmd [[au!]]
vim.cmd [[au FileType scala,sbt lua require("metals").initialize_or_attach(metals_config)]]
vim.cmd [[augroup end]]

-- Use a loop to conveniently call 'setup' on multiple servers and
-- map buffer local keybindings when the language server attaches
local servers = { "lemminx" }
for _, lsp in ipairs(servers) do
	nvim_lsp[lsp].setup {
		on_attach = on_attach,
		capabilities = capabilities,
		flags = {
			debounce_text_changes = 150,
		}
	}
end

vim.lsp.handlers["textDocument/publishDiagnostics"] = vim.lsp.with(
	vim.lsp.diagnostic.on_publish_diagnostics, {
		virtual_text = false,
		underline = true,
		signs = true,
	}
)

vim.cmd [[autocmd CursorHoldI * silent! lua vim.lsp.buf.signature_help()]]
vim.cmd [[autocmd CursorHold * lua vim.diagnostic.open_float({max_width = 100, focusable = false})]]