dots/.config/nvim/lua/rin/lsp/init.lua

-- TODO: show function signature help on hover
-- web, vimtex

-- Mappings.
-- See `:help vim.diagnostic.*` for documentation on any of the below functions
local opts = { noremap = true, silent = true }
vim.keymap.set('n', '<space>e', vim.diagnostic.open_float, opts)
vim.keymap.set('n', '[d', vim.diagnostic.goto_prev, opts)
vim.keymap.set('n', ']d', vim.diagnostic.goto_next, opts)
vim.keymap.set('n', '<space>q', vim.diagnostic.setloclist, opts)

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

    -- Mappings.
    -- See `:help vim.lsp.*` for documentation on any of the below functions
    local bufopts = { noremap = true, silent = true, buffer = bufnr }
    vim.keymap.set('n', 'gD', vim.lsp.buf.declaration, bufopts)
    vim.keymap.set('n', 'gd', vim.lsp.buf.definition, bufopts)
    vim.keymap.set('n', 'K', vim.lsp.buf.hover, bufopts)
    vim.keymap.set('n', 'gi', vim.lsp.buf.implementation, bufopts)
    vim.keymap.set('n', '<C-k>', vim.lsp.buf.signature_help, bufopts)
    vim.keymap.set('n', '<space>wa', vim.lsp.buf.add_workspace_folder, bufopts)
    vim.keymap.set('n', '<space>wr', vim.lsp.buf.remove_workspace_folder, bufopts)
    vim.keymap.set('n', '<space>wl', function()
        print(vim.inspect(vim.lsp.buf.list_workspace_folders()))
    end, bufopts)
    vim.keymap.set('n', '<space>D', vim.lsp.buf.type_definition, bufopts)
    vim.keymap.set('n', '<space>rn', vim.lsp.buf.rename, bufopts)
    vim.keymap.set('n', '<space>ca', vim.lsp.buf.code_action, bufopts)
    vim.keymap.set('n', 'gr', vim.lsp.buf.references, bufopts)
    vim.keymap.set('n', '<space>f', vim.lsp.buf.formatting, bufopts)
end

local lsp_flags = {
    -- This is the default in Nvim 0.7+
    debounce_text_changes = 150,
}

local servers = { 'tsserver', 'rust_analyzer', 'clangd', 'sumneko_lua' }
local lspconfig = require('lspconfig')

lspconfig['sumneko_lua'].setup {
    on_attach = on_attach,
    flags = lsp_flags,
    settings = {
        Lua = {
            runtime = {
                -- Tell the language server which version of Lua you're using (most likely LuaJIT in the case of Neovim)
                version = 'LuaJIT',
            },
            diagnostics = {
                -- Get the language server to recognize the `vim` global
                globals = { 'vim' },
            },
            workspace = {
                -- Make the server aware of Neovim runtime files
                library = vim.api.nvim_get_runtime_file("", true),
            },
            -- Do not send telemetry data containing a randomized but unique identifier
            telemetry = {
                enable = false,
            },
        },
    },
}

local capabilities = vim.lsp.protocol.make_client_capabilities()
capabilities = require('cmp_nvim_lsp').update_capabilities(capabilities)
for _, lsp in ipairs(servers) do
    lspconfig[lsp].setup {
        on_attach = on_attach,
        flags = lsp_flags,
        capabilities = capabilities,
    }
end

local luasnip = require 'luasnip'
local cmp = require 'cmp'
cmp.setup {
    snippet = {
        expand = function(args)
            luasnip.lsp_expand(args.body)
        end,
    },
    mapping = cmp.mapping.preset.insert({
        ['<C-d>'] = cmp.mapping.scroll_docs(-4),
        ['<C-f>'] = cmp.mapping.scroll_docs(4),
        ['<C-Space>'] = cmp.mapping.complete(),
        ['<CR>'] = cmp.mapping.confirm {
            behavior = cmp.ConfirmBehavior.Replace,
            select = true,
        },
        ['<Tab>'] = cmp.mapping(function(fallback)
            if cmp.visible() then
                cmp.select_next_item()
            elseif luasnip.expand_or_jumpable() then
                luasnip.expand_or_jump()
            else
                fallback()
            end
        end, { 'i', 's' }),
        ['<S-Tab>'] = cmp.mapping(function(fallback)
            if cmp.visible() then
                cmp.select_prev_item()
            elseif luasnip.jumpable(-1) then
                luasnip.jump(-1)
            else
                fallback()
            end
        end, { 'i', 's' }),
    }),
    sources = {
        { name = 'nvim_lsp' },
        { name = 'luasnip' },
    },
}