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

return {
  'neovim/nvim-lspconfig',
  event = { 'BufReadPre', 'BufNewFile' },
  dependencies = {
    -- Mason core
    { 'williamboman/mason.nvim', build = ':MasonUpdate', cmd = 'Mason', config = true },
    'williamboman/mason-lspconfig.nvim',
    'WhoIsSethDaniel/mason-tool-installer.nvim',

    -- Lua dev
    { 'folke/neodev.nvim', ft = 'lua', config = true },

    -- LSP UI & UX
    { 'j-hui/fidget.nvim', opts = {}, event = 'LspAttach' },
    { 'ray-x/lsp_signature.nvim', event = 'LspAttach' },

    -- Python venv selector
    {
      'linux-cultist/venv-selector.nvim',
      ft = 'python',
      opts = { auto_activate = true },
      config = true,
    },

    -- JSON Schema support
    { 'b0o/schemastore.nvim', ft = { 'json', 'yaml' } },
  },

  config = function()
    require('neodev').setup()

    -- Enhanced capabilities for LSP servers
    local capabilities = vim.lsp.protocol.make_client_capabilities()
    local has_cmp, cmp_nvim_lsp = pcall(require, 'cmp_nvim_lsp')
    if has_cmp then
      capabilities = cmp_nvim_lsp.default_capabilities(capabilities)
    end
    capabilities.offsetEncoding = { 'utf-8' }

    -- Disable dynamicRegistration to silence yamlls warning
    capabilities.workspace = capabilities.workspace or {}
    capabilities.workspace.didChangeConfiguration = capabilities.workspace.didChangeConfiguration or {}
    capabilities.workspace.didChangeConfiguration.dynamicRegistration = false

    local function path_exists(p)
      return p and p ~= '' and vim.uv.fs_stat(p) ~= nil
    end

    local function mason_bin(name)
      local p = vim.fs.joinpath(vim.fn.stdpath('data'), 'mason', 'bin', name)
      if path_exists(p) then
        return p
      end
      return name
    end

    local function julia_bin()
      local home = vim.env.HOME or ''
      local candidates = {
        vim.fn.exepath('julia'),
        vim.fs.joinpath(home, '.juliaup', 'bin', 'julia'),
        '/opt/homebrew/bin/julia',
        '/usr/local/bin/julia',
      }
      for _, p in ipairs(candidates) do
        if path_exists(p) then
          return p
        end
      end
      return 'julia'
    end

    -- Servers that should provide formatting
    local format_enabled_servers = {
      bashls = true,
      clangd = true,
      gopls = true,
      html = true,
      htmx = true,
      jsonls = true,
      lua_ls = true,
      marksman = true,
      pyright = true,
      ruff = true,
      rust_analyzer = true,
      taplo = true,
      texlab = true,
      yamlls = true,
      zls = true,
    }

    -- Default on_attach function
    local on_attach = function(client, bufnr)
      -- Enable formatting only for supported servers
      if not format_enabled_servers[client.name] then
        client.server_capabilities.documentFormattingProvider = false
        client.server_capabilities.documentRangeFormattingProvider = false
      end

      vim.bo[bufnr].omnifunc = 'v:lua.vim.lsp.omnifunc'

      -- LSP signature help
      require('lsp_signature').on_attach({
        hint_enable = false,
        handler_opts = { border = 'rounded' },
      }, bufnr)

      -- Keymap helper
      local function map(keys, func, desc, modes)
        modes = modes or 'n'
        vim.keymap.set(modes, keys, func, {
          buffer = bufnr,
          desc = desc and 'LSP: ' .. desc or nil,
        })
      end

      -- Lazy-load Telescope for LSP
      local function telescope_builtin(name)
        return function(...)
          require('lazy').load({ plugins = { 'telescope.nvim' } })
          return require('telescope.builtin')[name](...)
        end
      end

      -- Navigation
      map('gd', telescope_builtin('lsp_definitions'), '[G]oto [D]efinition')
      map('gD', vim.lsp.buf.declaration, '[G]oto [D]eclaration')
      map('gr', telescope_builtin('lsp_references'), '[G]oto [R]eferences')
      map('gI', telescope_builtin('lsp_implementations'), '[G]oto [I]mplementation')
      map('<leader>lT', telescope_builtin('lsp_type_definitions'), '[T]ype Definition')
      map('<leader>ls', telescope_builtin('lsp_document_symbols'), '[D]ocument [S]ymbols')
      map('<leader>lS', telescope_builtin('lsp_dynamic_workspace_symbols'), '[W]orkspace [S]ymbols')

      -- Diagnostics
      map('<leader>ld', vim.diagnostic.open_float, 'Show line [E]rrors')
      map('[d', vim.diagnostic.get_prev, 'Previous Diagnostic')
      map(']d', vim.diagnostic.get_next, 'Next Diagnostic')

      -- Code Actions & Refactoring
      map('<leader>lr', vim.lsp.buf.rename, 'Rename')
      map('<leader>la', vim.lsp.buf.code_action, 'Code Action', { 'n', 'v' })

      -- Documentation
      map('K', vim.lsp.buf.hover, 'Hover Documentation')
      map('<C-k>', vim.lsp.buf.signature_help, 'Signature Documentation')

      -- Document highlight
      if client.server_capabilities.documentHighlightProvider then
        local highlight_group = vim.api.nvim_create_augroup('lsp_document_highlight', { clear = true })
        local visual_bg = vim.fn.synIDattr(vim.fn.hlID('Visual'), 'bg') or '#3e4452'

        vim.api.nvim_set_hl(0, 'LspReferenceText', { bg = visual_bg })
        vim.api.nvim_set_hl(0, 'LspReferenceRead', { bg = visual_bg })
        vim.api.nvim_set_hl(0, 'LspReferenceWrite', { bg = visual_bg })
        vim.o.updatetime = math.max(vim.o.updatetime, 500)

        local function toggle_lsp_highlight(enable)
          if enable then
            vim.api.nvim_create_autocmd('CursorHold', {
              group = highlight_group,
              buffer = bufnr,
              callback = function()
                if client and client.server_capabilities.documentHighlightProvider then
                  vim.lsp.buf.document_highlight()
                end
              end,
            })
            vim.api.nvim_create_autocmd('CursorMoved', {
              group = highlight_group,
              buffer = bufnr,
              callback = vim.lsp.buf.clear_references,
            })
          else
            vim.api.nvim_clear_autocmds({ group = highlight_group, buffer = bufnr })
            vim.lsp.buf.clear_references()
          end
        end

        vim.api.nvim_buf_create_user_command(bufnr, 'LspToggleHighlight', function()
          local enabled = vim.b.lsp_highlight_enabled or false
          toggle_lsp_highlight(not enabled)
          vim.b.lsp_highlight_enabled = not enabled
          print('LSP document highlights ' .. (enabled and 'disabled' or 'enabled'))
        end, {})

        toggle_lsp_highlight(true)
      end
    end

    -- Default LSP configuration
    local default_config = {
      capabilities = capabilities,
      on_attach = on_attach,
      autostart = true,
    }

    local julia_cmd = julia_bin()
    local julia_ls_project = vim.fn.expand('~/.julia/environments/nvim-lsp')

    -- Server-specific configurations
    local servers = {
      bashls = {
        filetypes = { 'sh', 'bash', 'zsh' },
      },

      html = {
        filetypes = { 'html', 'htmldjango' },
        init_options = {
          configurationSection = { 'html', 'css', 'javascript' },
          embeddedLanguages = {
            css = true,
            javascript = true,
          },
        },
      },

      htmx = {
        cmd = { 'htmx-lsp' },
        filetypes = { 'html', 'htmx' },
      },

      gopls = {
        settings = {
          gopls = {
            gofumpt = true,
            staticcheck = true,
            completeUnimported = true,
            usePlaceholders = true,
            analyses = { unusedparams = true },
          },
        },
      },

      clangd = {
        cmd = {
          'clangd',
          '--background-index',
          '--clang-tidy',
          '--header-insertion=iwyu',
          '--completion-style=detailed',
          '--header-insertion-decorators',
          '--query-driver=/usr/bin/clang,/usr/bin/clang++',
          '--enable-config',
        },
        settings = {
          formatting = true,
          inlayHints = {
            designators = true,
            enabled = true,
            parameterNames = true,
            deducedTypes = true,
          },
        },
        filetypes = { 'c', 'cpp', 'objc', 'objcpp', 'h', 'hpp', 'hxx' },
      },

      marksman = {
        filetypes = { 'markdown' },
        settings = {
          marksman = {
            extensions = { 'mdx' },
          },
        },
      },

      jsonls = {
        cmd = { 'vscode-json-language-server', '--stdio' },
        settings = {
          json = {
            validate = { enable = true },
          },
        },
      },

      julials = {
        filetypes = { 'julia' },
        cmd = {
          julia_cmd,
          '--project=' .. julia_ls_project,
          '--startup-file=no',
          '--history-file=no',
          '-e',
          [[
      using Logging
      using LanguageServer
      using SymbolServer

      global_logger(ConsoleLogger(stderr, Logging.Warn))

      function project_path()
        try
          return LanguageServer.find_project_path(pwd())
        catch
          return pwd()
        end
      end

      depot_path = get(ENV, "JULIA_DEPOT_PATH", "")

      server = LanguageServer.LanguageServerInstance(
        stdin,
        stdout,
        something(project_path(), pwd()),
        depot_path,
      )

      server.runlinter = true
      run(server)
    ]],
        },
        settings = {
          julia = {
            lint = {
              run = true,
            },
          },
        },
        on_attach = function(client, bufnr)
          on_attach(client, bufnr)
          -- Julia must never format via LSP
          client.server_capabilities.documentFormattingProvider = false
          client.server_capabilities.documentRangeFormattingProvider = false
        end,
      },

      pyright = {
        settings = {
          python = {
            analysis = {
              autoSearchPaths = true,
              diagnosticMode = 'workspace',
              useLibraryCodeForTypes = true,
              typeCheckingMode = 'none',
              reportGeneralTypeIssues = false,
            },
          },
        },
      },

      ruff = {
        filetypes = { 'python' },
        on_init = function()
          vim.api.nvim_create_autocmd('LspAttach', {
            group = vim.api.nvim_create_augroup('lsp_attach_disable_ruff_hover', { clear = true }),
            callback = function(args)
              local client = vim.lsp.get_client_by_id(args.data.client_id)
              if client and client.name == 'ruff' then
                -- Disable Ruff hover
                client.server_capabilities.hoverProvider = false
              end
            end,
            desc = 'LSP: Disable hover capability from Ruff',
          })
        end,
      },

      rust_analyzer = {
        settings = {
          ['rust-analyzer'] = {
            imports = { granularity = { group = 'module' }, prefix = 'self' },
            cargo = { buildScripts = { enable = true } },
            procMacro = { enable = true },
            checkOnSave = { command = 'clippy' },
          },
        },
      },

      taplo = {
        filetypes = { 'toml' },
      },

      yamlls = {
        settings = {
          yaml = {
            schemaStore = { enable = true },
            validate = true,
          },
        },
      },

      texlab = {
        filetypes = { 'tex', 'plaintex', 'bib', 'cls', 'sty' },
        settings = {
          texlab = {
            build = {
              onSave = false,
            },
            diagnostics = {
              ignoredPatterns = {
                '^Overfull \\\\hbox',
                '^Underfull \\\\hbox',
                '^Package.*Warning',
              },
            },
            auxDirectory = 'output',
          },
        },
      },

      lua_ls = {
        cmd = { mason_bin('lua-language-server') },
        settings = {
          Lua = {
            workspace = { checkThirdParty = false },
            telemetry = { enable = false },
            diagnostics = { globals = { 'vim' } },
          },
        },
      },

      sqls = {
        filetypes = { 'sql', 'mysql', 'plsql', 'postgresql' },
        settings = {
          sql = {
            connections = {
              {
                driver = 'sqlite3',
                dataSourceName = 'file::memory:?cache=shared',
              },
            },
          },
        },
        on_init = function(client)
          local root_dir = client.config.root_dir or vim.fn.getcwd()
          local db_files = vim.fn.globpath(root_dir, '*.db', false, true)
          vim.list_extend(db_files, vim.fn.globpath(root_dir, '*.sqlite', false, true))

          if #db_files > 0 then
            local connections = {}
            for _, path in ipairs(db_files) do
              table.insert(connections, {
                driver = 'sqlite3',
                dataSourceName = vim.fn.fnamemodify(path, ':p'),
              })
            end
            client.config.settings.sql.connections = connections
            client.notify('workspace/didChangeConfiguration', { settings = client.config.settings })
          end
        end,
      },

      zls = {
        filetypes = { 'zig' },
      },
    }

    -- Use Mason to ensure servers are installed
    local ensure_installed = vim.tbl_keys(servers)
    ensure_installed = vim.tbl_filter(function(name)
      return name ~= 'julials'
    end, ensure_installed)

    require('mason-lspconfig').setup({
      ensure_installed = ensure_installed,
      automatic_enable = false,
    })

    local function get_lspconfig_defaults(server_name)
      local ok, cfg = pcall(require, 'lspconfig.configs.' .. server_name)
      if ok and cfg and cfg.default_config then
        local defaults = vim.deepcopy(cfg.default_config)
        if type(defaults.root_dir) == 'function' then
          local orig_root_dir = defaults.root_dir
          defaults.root_dir = function(bufnr, on_dir)
            local fname = bufnr
            if type(bufnr) == 'number' then
              fname = vim.api.nvim_buf_get_name(bufnr)
              if fname == '' or type(fname) ~= 'string' or fname:match('^%w+://') then
                fname = vim.fn.getcwd()
              end
            end

            local root = orig_root_dir(fname)
            if type(on_dir) == 'function' then
              on_dir(root)
              return
            end
            return root
          end
        end
        return defaults
      end
      return {}
    end

    -- Setup and enable LSP servers
    for server_name, config in pairs(servers) do
      if config then
        local lspconfig_defaults = get_lspconfig_defaults(server_name)

        -- Merge default config with server-specific config
        local merged_config = vim.tbl_deep_extend('force', lspconfig_defaults, default_config, config)

        -- Configure and enable the server
        vim.lsp.config(server_name, merged_config)
        vim.lsp.enable(server_name)
      end
    end

    -- Diagnostics configuration
    vim.diagnostic.config({
      underline = true,
      severity_sort = true,
      signs = {
        text = {
          [vim.diagnostic.severity.ERROR] = 'E',
          [vim.diagnostic.severity.WARN] = 'W',
          [vim.diagnostic.severity.HINT] = 'H',
          [vim.diagnostic.severity.INFO] = 'I',
        },
        linehl = {
          [vim.diagnostic.severity.ERROR] = 'ErrorMsg',
        },
        numhl = {
          [vim.diagnostic.severity.WARN] = 'WarningMsg',
        },
      },
      virtual_text = { spacing = 2, prefix = '●' },
      float = { source = 'if_many', border = 'rounded' },
    })
  end,
}