nvim/lua/plugins/lsp.lua

-- LSP settings.
--  This function gets run when an LSP connects to a particular buffer.
local on_attach = function(_, bufnr)
  -- NOTE: Remember that lua is a real programming language, and as such it is possible
  -- to define small helper and utility functions so you don't have to repeat yourself
  -- many times.
  --
  -- In this case, we create a function that lets us more easily define mappings specific
  -- for LSP related items. It sets the mode, buffer and description for us each time.
  local nmap = function(keys, func, desc)
    if desc then
      desc = 'LSP: ' .. desc
    end

    vim.keymap.set('n', keys, func, { buffer = bufnr, desc = desc })
  end

  local delayed_format = function()
    vim.lsp.buf.format({ timeout_ms = 2000 })
  end

  nmap('<leader>rn', vim.lsp.buf.rename, '[R]e[n]ame')
  nmap('<leader>ca', vim.lsp.buf.code_action, '[C]ode [A]ction')
  nmap('<leader>ff', delayed_format, '[F]ormat')

  nmap('gd', vim.lsp.buf.definition, '[G]oto [D]efinition')
  nmap('gr', require('telescope.builtin').lsp_references, '[G]oto [R]eferences')
  nmap('gI', vim.lsp.buf.implementation, '[G]oto [I]mplementation')
  nmap('<leader>D', vim.lsp.buf.type_definition, 'Type [D]efinition')
  nmap('<leader>ds', require('telescope.builtin').lsp_document_symbols, '[D]ocument [S]ymbols')
  nmap('<leader>ws', require('telescope.builtin').lsp_dynamic_workspace_symbols, '[W]orkspace [S]ymbols')

  -- See `:help K` for why this keymap
  nmap('K', vim.lsp.buf.hover, 'Hover Documentation')
  nmap('<C-k>', vim.lsp.buf.signature_help, 'Signature Documentation')

  -- Lesser used LSP functionality
  nmap('gD', vim.lsp.buf.declaration, '[G]oto [D]eclaration')
  nmap('<leader>wa', vim.lsp.buf.add_workspace_folder, '[W]orkspace [A]dd Folder')
  nmap('<leader>wr', vim.lsp.buf.remove_workspace_folder, '[W]orkspace [R]emove Folder')
  nmap('<leader>wl', function()
    print(vim.inspect(vim.lsp.buf.list_workspace_folders()))
  end, '[W]orkspace [L]ist Folders')

  -- Create a command `:Format` local to the LSP buffer
  vim.api.nvim_buf_create_user_command(bufnr, 'Format', function(_)
    vim.lsp.buf.format()
  end, { desc = 'Format current buffer with LSP' })
end

return {
  { -- LSP Configuration & Plugins
    'neovim/nvim-lspconfig',
    dependencies = {
      -- Automatically install LSPs to stdpath for neovim
      'williamboman/mason.nvim',
      'williamboman/mason-lspconfig.nvim',

      -- Useful status updates for LSP
      { 'j-hui/fidget.nvim', opts = {} },

      -- Additional lua configuration, makes nvim stuff amazing!
      'folke/neodev.nvim',
    },

    config = function ()
      local servers = {
        -- clangd = {},
        -- gopls = {},
        marksman = {},
        pyright = {},
        tsserver = {},
        solc = {},

        rust_analyzer = {
          checkOnSave = {
            allFeatures = true,
            overrideCommand = {
              'cargo', 'clippy', '--workspace', '--message-format=json',
              '--all-targets', '--all-features'
            }
          }
        },
        lua_ls = {
          Lua = {
            workspace = { checkThirdParty = false },
            telemetry = { enable = false },
          },
        },
      }

      -- Setup neovim lua configuration
      require('neodev').setup()

      -- nvim-cmp supports additional completion capabilities, so broadcast that to servers
      local capabilities = vim.lsp.protocol.make_client_capabilities()
      capabilities = require('cmp_nvim_lsp').default_capabilities(capabilities)

      -- Setup mason so it can manage external tooling
      require('mason').setup()

      -- Ensure the servers above are installed
      local mason_lspconfig = require 'mason-lspconfig'

      mason_lspconfig.setup {
        ensure_installed = vim.tbl_keys(servers),
      }

      mason_lspconfig.setup_handlers {
        function(server_name)
          require('lspconfig')[server_name].setup {
            capabilities = capabilities,
            on_attach = on_attach,
            settings = servers[server_name],
          }
        end,
      }
    end
  },

  { -- inject lsp formatting, diagonstics etc
    'jose-elias-alvarez/null-ls.nvim',

    dependencies = { 'nvim-lua/plenary.nvim' },

    config = function ()
      local null_ls = require("null-ls")

      null_ls.setup({
        sources = {
          -- general
          null_ls.builtins.code_actions.gitsigns,
          -- python
          -- null_ls.builtins.diagnostics.pylint,
          null_ls.builtins.formatting.black,
          null_ls.builtins.formatting.isort,
          -- typescript
          null_ls.builtins.formatting.prettier,
          -- rust
          -- null_ls.builtins.formatting.rustfmt,
        },
      })
    end
  }
}