nvim/lua/plugins/lsp.lua

-- lua/plugins/lsp.lua
-- Language Server Protocol: mason + nvim-lspconfig + lazydev + fidget

return {
  {
    -- Lua LSP annotations for Neovim API
    'folke/lazydev.nvim',
    ft = 'lua',
    opts = {
      library = {
        { path = '${3rd}/luv/library', words = { 'vim%.uv' } },
      },
    },
  },

  {
    'neovim/nvim-lspconfig',
    dependencies = {
      { 'mason-org/mason.nvim', opts = {} },
      'mason-org/mason-lspconfig.nvim',
      'WhoIsSethDaniel/mason-tool-installer.nvim',
      { 'j-hui/fidget.nvim', opts = {} },
      'saghen/blink.cmp',
    },
    config = function()
      -- Keymaps attached per-buffer when an LSP connects
      vim.api.nvim_create_autocmd('LspAttach', {
        group = vim.api.nvim_create_augroup('user-lsp-attach', { clear = true }),
        callback = function(event)
          local map = function(keys, func, desc, mode)
            vim.keymap.set(mode or 'n', keys, func, { buffer = event.buf, desc = 'LSP: ' .. desc })
          end

          local tb = require 'telescope.builtin'
          map('grn',  vim.lsp.buf.rename,          '[R]e[n]ame')
          map('gra',  vim.lsp.buf.code_action,     '[G]oto Code [A]ction', { 'n', 'x' })
          map('grr',  tb.lsp_references,           '[G]oto [R]eferences')
          map('gri',  tb.lsp_implementations,      '[G]oto [I]mplementation')
          map('grd',  tb.lsp_definitions,          '[G]oto [D]efinition')
          map('grD',  vim.lsp.buf.declaration,     '[G]oto [D]eclaration')
          map('gO',   tb.lsp_document_symbols,     'Open Document Symbols')
          map('gW',   tb.lsp_dynamic_workspace_symbols, 'Open Workspace Symbols')
          map('grt',  tb.lsp_type_definitions,     '[G]oto [T]ype Definition')

          -- Compat helper for 0.10 vs 0.11
          local function client_supports(client, method, bufnr)
            if vim.fn.has 'nvim-0.11' == 1 then
              return client:supports_method(method, bufnr)
            else
              return client.supports_method(method, { bufnr = bufnr })
            end
          end

          local client = vim.lsp.get_client_by_id(event.data.client_id)

          -- Document highlight on CursorHold
          if client and client_supports(client, vim.lsp.protocol.Methods.textDocument_documentHighlight, event.buf) then
            local hl_group = vim.api.nvim_create_augroup('user-lsp-highlight', { clear = false })
            vim.api.nvim_create_autocmd({ 'CursorHold', 'CursorHoldI' }, {
              buffer = event.buf, group = hl_group, callback = vim.lsp.buf.document_highlight,
            })
            vim.api.nvim_create_autocmd({ 'CursorMoved', 'CursorMovedI' }, {
              buffer = event.buf, group = hl_group, callback = vim.lsp.buf.clear_references,
            })
            vim.api.nvim_create_autocmd('LspDetach', {
              group = vim.api.nvim_create_augroup('user-lsp-detach', { clear = true }),
              callback = function(ev)
                vim.lsp.buf.clear_references()
                vim.api.nvim_clear_autocmds { group = 'user-lsp-highlight', buffer = ev.buf }
              end,
            })
          end

          -- Inlay hints toggle
          if client and client_supports(client, vim.lsp.protocol.Methods.textDocument_inlayHint, event.buf) then
            map('<leader>th', function()
              vim.lsp.inlay_hint.enable(not vim.lsp.inlay_hint.is_enabled { bufnr = event.buf })
            end, '[T]oggle Inlay [H]ints')
          end
        end,
      })

      -- Diagnostics appearance
      vim.diagnostic.config {
        severity_sort = true,
        float  = { border = 'rounded', source = 'if_many' },
        underline = { severity = vim.diagnostic.severity.ERROR },
        signs  = vim.g.have_nerd_font and {
          text = {
            [vim.diagnostic.severity.ERROR] = '󰅚 ',
            [vim.diagnostic.severity.WARN]  = '󰀪 ',
            [vim.diagnostic.severity.INFO]  = '󰋽 ',
            [vim.diagnostic.severity.HINT]  = '󰌶 ',
          },
        } or {},
        virtual_text = {
          source  = 'if_many',
          spacing = 2,
          format  = function(d) return d.message end,
        },
      }

      -- Capabilities enhanced by blink.cmp
      local capabilities = require('blink.cmp').get_lsp_capabilities()

      -- Language servers to install and configure
      -- Add more servers here as needed; see `:help lspconfig-all`
      local servers = {
        lua_ls = {
          settings = {
            Lua = {
              completion = { callSnippet = 'Replace' },
            },
          },
        },
      }

      local ensure_installed = vim.tbl_keys(servers)
      vim.list_extend(ensure_installed, { 'stylua' })
      require('mason-tool-installer').setup { ensure_installed = ensure_installed }

      require('mason-lspconfig').setup {
        ensure_installed = {},
        automatic_installation = false,
        handlers = {
          function(server_name)
            local server = servers[server_name] or {}
            server.capabilities = vim.tbl_deep_extend('force', {}, capabilities, server.capabilities or {})
            require('lspconfig')[server_name].setup(server)
          end,
        },
      }
    end,
  },
}