nvim/lua/custom/plugins/lsp-config.lua

return { -- LSP Configuration & Plugins
  'neovim/nvim-lspconfig',
  dependencies = {
    -- Automatically install LSPs and related tools to stdpath for Neovim
    { 'williamboman/mason.nvim', config = true }, -- NOTE: Must be loaded before dependants
    'williamboman/mason-lspconfig.nvim',
    'WhoIsSethDaniel/mason-tool-installer.nvim',

    -- Useful status updates for LSP.
    -- NOTE: `opts = {}` is the same as calling `require('fidget').setup({})`
    -- { 'j-hui/fidget.nvim', opts = {} },

    -- `neodev` configures Lua LSP for your Neovim config, runtime and plugins
    -- used for completion, annotations and signatures of Neovim apis
    { 'folke/lazydev.nvim', opts = {} },
  },
  config = function()
    -- Brief aside: **What is LSP?**
    --
    -- LSP is an initialism you've probably heard, but might not understand what it is.
    --
    -- LSP stands for Language Server Protocol. It's a protocol that helps editors
    -- and language tooling communicate in a standardized fashion.
    --
    -- In general, you have a "server" which is some tool built to understand a particular
    -- language (such as `gopls`, `lua_ls`, `rust_analyzer`, etc.). These Language Servers
    -- (sometimes called LSP servers, but that's kind of like ATM Machine) are standalone
    -- processes that communicate with some "client" - in this case, Neovim!
    --
    -- LSP provides Neovim with features like:
    --  - Go to definition
    --  - Find references
    --  - Autocompletion
    --  - Symbol Search
    --  - and more!
    --
    -- Thus, Language Servers are external tools that must be installed separately from
    -- Neovim. This is where `mason` and related plugins come into play.
    --
    -- If you're wondering about lsp vs treesitter, you can check out the wonderfully
    -- and elegantly composed help section, `:help lsp-vs-treesitter`

    --  This function gets run when an LSP attaches to a particular buffer.
    --    That is to say, every time a new file is opened that is associated with
    --    an lsp (for example, opening `main.rs` is associated with `rust_analyzer`) this
    --    function will be executed to configure the current buffer
    vim.api.nvim_create_autocmd('LspAttach', {
      group = vim.api.nvim_create_augroup('kickstart-lsp-attach', { clear = true }),
      callback = function(event)
        -- 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.
        --
        -- 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 map = function(keys, func, desc)
          vim.keymap.set('n', keys, func, { buffer = event.buf, desc = 'LSP: ' .. desc })
        end

        -- Jump to the definition of the word under your cursor.
        --  This is where a variable was first declared, or where a function is defined, etc.
        --  To jump back, press <C-t>.
        map('gd', require('telescope.builtin').lsp_definitions, '[G]oto [D]efinition')

        -- Find references for the word under your cursor.
        map('gr', require('telescope.builtin').lsp_references, '[G]oto [R]eferences')

        -- Jump to the implementation of the word under your cursor.
        --  Useful when your language has ways of declaring types without an actual implementation.
        map('gI', require('telescope.builtin').lsp_implementations, '[G]oto [I]mplementation')

        -- Jump to the type of the word under your cursor.
        --  Useful when you're not sure what type a variable is and you want to see
        --  the definition of its *type*, not where it was *defined*.
        map('<leader>D', require('telescope.builtin').lsp_type_definitions, 'Type [D]efinition')

        -- Fuzzy find all the symbols in your current document.
        --  Symbols are things like variables, functions, types, etc.
        map('<leader>ds', require('telescope.builtin').lsp_document_symbols, '[D]ocument [S]ymbols')

        -- Fuzzy find all the symbols in your current workspace.
        --  Similar to document symbols, except searches over your entire project.
        map('<leader>ws', require('telescope.builtin').lsp_dynamic_workspace_symbols, '[W]orkspace [S]ymbols')

        -- Rename the variable under your cursor.
        --  Most Language Servers support renaming across files, etc.
        map('<leader>rn', vim.lsp.buf.rename, '[R]e[n]ame')

        -- Execute a code action, usually your cursor needs to be on top of an error
        -- or a suggestion from your LSP for this to activate.
        map('<leader>ca', vim.lsp.buf.code_action, '[C]ode [A]ction')

        -- Opens a popup that displays documentation about the word under your cursor
        --  See `:help K` for why this keymap.
        map('K', vim.lsp.buf.hover, 'Hover Documentation')

        -- WARN: This is not Goto Definition, this is Goto Declaration.
        --  For example, in C this would take you to the header.
        map('gD', vim.lsp.buf.declaration, '[G]oto [D]eclaration')

        -- The following two autocommands are used to highlight references of the
        -- word under your cursor when your cursor rests there for a little while.
        --    See `:help CursorHold` for information about when this is executed
        --
        -- When you move your cursor, the highlights will be cleared (the second autocommand).
        local client = vim.lsp.get_client_by_id(event.data.client_id)
        if client and client.server_capabilities.documentHighlightProvider then
          local highlight_augroup = vim.api.nvim_create_augroup('kickstart-lsp-highlight', { clear = false })
          vim.api.nvim_create_autocmd({ 'CursorHold', 'CursorHoldI' }, {
            buffer = event.buf,
            group = highlight_augroup,
            callback = vim.lsp.buf.document_highlight,
          })

          vim.api.nvim_create_autocmd({ 'CursorMoved', 'CursorMovedI' }, {
            buffer = event.buf,
            group = highlight_augroup,
            callback = vim.lsp.buf.clear_references,
          })

          vim.api.nvim_create_autocmd('LspDetach', {
            group = vim.api.nvim_create_augroup('kickstart-lsp-detach', { clear = true }),
            callback = function(event2)
              vim.lsp.buf.clear_references()
              vim.api.nvim_clear_autocmds { group = 'kickstart-lsp-highlight', buffer = event2.buf }
            end,
          })
        end

        -- The following autocommand is used to enable inlay hints in your
        -- code, if the language server you are using supports them
        --
        -- This may be unwanted, since they displace some of your code
        if client and client.server_capabilities.inlayHintProvider and vim.lsp.inlay_hint then
          map('<leader>th', function()
            vim.lsp.inlay_hint.enable(not vim.lsp.inlay_hint.is_enabled())
          end, '[T]oggle Inlay [H]ints')
        end
      end,
    })

    -- LSP servers and clients are able to communicate to each other what features they support.
    --  By default, Neovim doesn't support everything that is in the LSP specification.
    --  When you add nvim-cmp, luasnip, etc. Neovim now has *more* capabilities.
    --  So, we create new capabilities with nvim cmp, and then broadcast that to the servers.
    local capabilities = vim.lsp.protocol.make_client_capabilities()
    capabilities = vim.tbl_deep_extend('force', capabilities, require('cmp_nvim_lsp').default_capabilities())

    -- Enable the following language servers
    --  Feel free to add/remove any LSPs that you want here. They will automatically be installed.
    --
    --  Add any additional override configuration in the following tables. Available keys are:
    --  - cmd (table): Override the default command used to start the server
    --  - filetypes (table): Override the default list of associated filetypes for the server
    --  - capabilities (table): Override fields in capabilities. Can be used to disable certain LSP features.
    --  - settings (table): Override the default settings passed when initializing the server.
    --        For example, to see the options for `lua_ls`, you could go to: https://luals.github.io/wiki/settings/
    local lspconfig = require 'lspconfig'
    local root_patterns = { 'CMakeLists.txt', '.git' }
    local servers = {
      clangd = {
        -- tell clangd where to find compile_commands.json
        cmd = {
          'clangd',
          '--background-index',
          '--clang-tidy',
          '--compile-commands-dir=build', -- <-- point at the build folder
        },
        root_dir = lspconfig.util.root_pattern(unpack(root_patterns)),
        -- clangd auto-detects filetypes c/cpp/etc.
      },
      arduino_language_server = {
        -- point at the binary (Mason puts it on your PATH)
        cmd = {
          'arduino-language-server',
          '-cli',
          'arduino-cli',
          '-cli-config',
          os.getenv 'HOME' .. '/.arduino15/arduino-cli.yaml',
          '-fqbn',
          'arduino:avr:uno', -- <- replace with your board’s FQBN
          '--verbose',
        },
        filetypes = { 'arduino', 'ino', 'pde' },
        root_dir = function(fname)
          return lspconfig.util.root_pattern('*.ino', '.git')(fname) or vim.loop.cwd()
        end,
        settings = {}, -- no extra settings for now
      },
      gopls = {},
      pyrefly = {},
      --pyright = {},
      rust_analyzer = {},
      markdownlint = {},
      -- ... etc. See `:help lspconfig-all` for a list of all the pre-configured LSPs
      --
      -- Some languages (like typescript) have entire language plugins that can be useful:
      --    https://github.com/pmizio/typescript-tools.nvim
      --
      -- But for many setups, the LSP (`tsserver`) will work just fine
      ts_ls = {},
      --

      lua_ls = {
        -- cmd = {...},
        -- filetypes = { ...},
        -- capabilities = {},
        settings = {
          Lua = {
            completion = {
              callSnippet = 'Replace',
            },
            -- You can toggle below to ignore Lua_LS's noisy `missing-fields` warnings
            diagnostics = { disable = { 'missing-fields' } },
          },
        },
      },
    }

    -- Ensure the servers and tools above are installed
    --  To check the current status of installed tools and/or manually install
    --  other tools, you can run
    --    :Mason
    --
    --  You can press `g?` for help in this menu.
    require('mason').setup()

    -- You can add other tools here that you want Mason to install
    -- for you, so that they are available from within Neovim.
    local ensure_installed = vim.tbl_keys(servers or {})
    vim.list_extend(ensure_installed, {
      -- Lua
      'stylua',
      -- TS / JS
      'html-lsp',
      'css-lsp',
      'prettier',
      'prettierd',
      'typescript-language-server',
      -- Python
      'ruff',
      'pyrefly',
      --'pyright',
      -- C
      'clangd',
      -- markdown
      'marksman',
      'markdownlint',
      -- json
      'json-lsp',
    })

    require('mason-tool-installer').setup { ensure_installed = ensure_installed }

    require('mason-lspconfig').setup {
      ensure_installed = servers,
      automatic_installation = true,
      handlers = {
        function(server_name)
          local server = servers[server_name] or {}

          -- This handles overriding only values explicitly passed
          -- by the server configuration above. Useful when disabling
          -- certain features of an LSP (for example, turning off formatting for tsserver)
          server.capabilities = vim.tbl_deep_extend('force', {}, capabilities, server.capabilities or {})
          require('lspconfig')[server_name].setup(server)
        end,
      },
    }
  end,
}