neovim/runtime/lua/vim/lsp.lua

local api = vim.api
local validate = vim.validate

local lsp = vim._defer_require('vim.lsp', {
  _changetracking = ..., --- @module 'vim.lsp._changetracking'
  _folding_range = ..., --- @module 'vim.lsp._folding_range'
  _snippet_grammar = ..., --- @module 'vim.lsp._snippet_grammar'
  _tagfunc = ..., --- @module 'vim.lsp._tagfunc'
  _watchfiles = ..., --- @module 'vim.lsp._watchfiles'
  buf = ..., --- @module 'vim.lsp.buf'
  client = ..., --- @module 'vim.lsp.client'
  codelens = ..., --- @module 'vim.lsp.codelens'
  completion = ..., --- @module 'vim.lsp.completion'
  diagnostic = ..., --- @module 'vim.lsp.diagnostic'
  handlers = ..., --- @module 'vim.lsp.handlers'
  inlay_hint = ..., --- @module 'vim.lsp.inlay_hint'
  log = ..., --- @module 'vim.lsp.log'
  protocol = ..., --- @module 'vim.lsp.protocol'
  rpc = ..., --- @module 'vim.lsp.rpc'
  semantic_tokens = ..., --- @module 'vim.lsp.semantic_tokens'
  util = ..., --- @module 'vim.lsp.util'
})

local log = lsp.log
local protocol = lsp.protocol
local ms = protocol.Methods
local util = lsp.util
local changetracking = lsp._changetracking

-- Export these directly from rpc.
---@nodoc
lsp.rpc_response_error = lsp.rpc.rpc_response_error

lsp._resolve_to_request = {
  [ms.codeAction_resolve] = ms.textDocument_codeAction,
  [ms.codeLens_resolve] = ms.textDocument_codeLens,
  [ms.documentLink_resolve] = ms.textDocument_documentLink,
  [ms.inlayHint_resolve] = ms.textDocument_inlayHint,
}

-- TODO improve handling of scratch buffers with LSP attached.

---@private
--- Called by the client when trying to call a method that's not
--- supported in any of the servers registered for the current buffer.
---@param method (string) name of the method
function lsp._unsupported_method(method)
  local msg = string.format(
    'method %s is not supported by any of the servers registered for the current buffer',
    method
  )
  log.warn(msg)
  return msg
end

---@private
---@param workspace_folders string|lsp.WorkspaceFolder[]?
---@return lsp.WorkspaceFolder[]?
function lsp._get_workspace_folders(workspace_folders)
  if type(workspace_folders) == 'table' then
    return workspace_folders
  elseif type(workspace_folders) == 'string' then
    return {
      {
        uri = vim.uri_from_fname(workspace_folders),
        name = workspace_folders,
      },
    }
  end
end

local wait_result_reason = { [-1] = 'timeout', [-2] = 'interrupted', [-3] = 'error' }

local format_line_ending = {
  ['unix'] = '\n',
  ['dos'] = '\r\n',
  ['mac'] = '\r',
}

---@private
---@param bufnr (number)
---@return string
function lsp._buf_get_line_ending(bufnr)
  return format_line_ending[vim.bo[bufnr].fileformat] or '\n'
end

-- Tracks all clients created via lsp.start_client
local all_clients = {} --- @type table<integer,vim.lsp.Client>

local client_errors_base = table.maxn(lsp.rpc.client_errors)
local client_errors_offset = 0

local function client_error(name)
  client_errors_offset = client_errors_offset + 1
  local index = client_errors_base + client_errors_offset
  return { [name] = index, [index] = name }
end

--- Error codes to be used with `on_error` from |vim.lsp.start_client|.
--- Can be used to look up the string from a the number or the number
--- from the string.
--- @nodoc
lsp.client_errors = vim.tbl_extend(
  'error',
  lsp.rpc.client_errors,
  client_error('BEFORE_INIT_CALLBACK_ERROR'),
  client_error('ON_INIT_CALLBACK_ERROR'),
  client_error('ON_ATTACH_ERROR'),
  client_error('ON_EXIT_CALLBACK_ERROR')
)

---@private
--- Returns full text of buffer {bufnr} as a string.
---
---@param bufnr (number) Buffer handle, or 0 for current.
---@return string # Buffer text as string.
function lsp._buf_get_full_text(bufnr)
  local line_ending = lsp._buf_get_line_ending(bufnr)
  local text = table.concat(api.nvim_buf_get_lines(bufnr, 0, -1, true), line_ending)
  if vim.bo[bufnr].eol then
    text = text .. line_ending
  end
  return text
end

--- Memoizes a function. On first run, the function return value is saved and
--- immediately returned on subsequent runs. If the function returns a multival,
--- only the first returned value will be memoized and returned. The function will only be run once,
--- even if it has side effects.
---
---@generic T: function
---@param fn (T) Function to run
---@return T
local function once(fn)
  local value --- @type function
  local ran = false
  return function(...)
    if not ran then
      value = fn(...) --- @type function
      ran = true
    end
    return value
  end
end

--- @param client vim.lsp.Client
--- @param config vim.lsp.ClientConfig
--- @return boolean
local function reuse_client_default(client, config)
  if client.name ~= config.name then
    return false
  end

  local config_folders = lsp._get_workspace_folders(config.workspace_folders or config.root_dir)

  if not config_folders or not next(config_folders) then
    -- Reuse if the client was configured with no workspace folders
    local client_config_folders =
      lsp._get_workspace_folders(client.config.workspace_folders or client.config.root_dir)
    return not client_config_folders or not next(client_config_folders)
  end

  for _, config_folder in ipairs(config_folders) do
    local found = false
    for _, client_folder in ipairs(client.workspace_folders or {}) do
      if config_folder.uri == client_folder.uri then
        found = true
        break
      end
    end
    if not found then
      return false
    end
  end

  return true
end

--- Reset defaults set by `set_defaults`.
--- Must only be called if the last client attached to a buffer exits.
local function reset_defaults(bufnr)
  if vim.bo[bufnr].tagfunc == 'v:lua.vim.lsp.tagfunc' then
    vim.bo[bufnr].tagfunc = nil
  end
  if vim.bo[bufnr].omnifunc == 'v:lua.vim.lsp.omnifunc' then
    vim.bo[bufnr].omnifunc = nil
  end
  if vim.bo[bufnr].formatexpr == 'v:lua.vim.lsp.formatexpr()' then
    vim.bo[bufnr].formatexpr = nil
  end
  vim._with({ buf = bufnr }, function()
    local keymap = vim.fn.maparg('K', 'n', false, true)
    if keymap and keymap.callback == vim.lsp.buf.hover and keymap.buffer == 1 then
      vim.keymap.del('n', 'K', { buffer = bufnr })
    end
  end)
end

--- @param code integer
--- @param signal integer
--- @param client_id integer
local function on_client_exit(code, signal, client_id)
  local client = all_clients[client_id]

  vim.schedule(function()
    for bufnr in pairs(client.attached_buffers) do
      if client and client.attached_buffers[bufnr] and api.nvim_buf_is_valid(bufnr) then
        api.nvim_exec_autocmds('LspDetach', {
          buffer = bufnr,
          modeline = false,
          data = { client_id = client_id },
        })
      end

      client.attached_buffers[bufnr] = nil

      if #lsp.get_clients({ bufnr = bufnr, _uninitialized = true }) == 0 then
        reset_defaults(bufnr)
      end
    end

    local namespace = vim.lsp.diagnostic.get_namespace(client_id)
    vim.diagnostic.reset(namespace)
  end)

  local name = client.name or 'unknown'

  -- Schedule the deletion of the client object so that it exists in the execution of LspDetach
  -- autocommands
  vim.schedule(function()
    all_clients[client_id] = nil

    -- Client can be absent if executable starts, but initialize fails
    -- init/attach won't have happened
    if client then
      changetracking.reset(client)
    end
    if code ~= 0 or (signal ~= 0 and signal ~= 15) then
      local msg = string.format(
        'Client %s quit with exit code %s and signal %s. Check log for errors: %s',
        name,
        code,
        signal,
        lsp.get_log_path()
      )
      vim.notify(msg, vim.log.levels.WARN)
    end
  end)
end

--- Creates and initializes a client with the given configuration.
--- @param config vim.lsp.ClientConfig Configuration for the server.
--- @return integer? client_id |vim.lsp.get_client_by_id()| Note: client may not be
---         fully initialized. Use `on_init` to do any actions once
---         the client has been initialized.
--- @return string? # Error message, if any
local function create_and_initialize_client(config)
  local ok, res = pcall(require('vim.lsp.client').create, config)
  if not ok then
    return nil, res --[[@as string]]
  end

  local client = assert(res)

  --- @diagnostic disable-next-line: invisible
  table.insert(client._on_exit_cbs, on_client_exit)

  all_clients[client.id] = client

  client:initialize()

  return client.id, nil
end

--- @class vim.lsp.Config : vim.lsp.ClientConfig
---
--- See `cmd` in [vim.lsp.ClientConfig].
--- @field cmd? string[]|fun(dispatchers: vim.lsp.rpc.Dispatchers): vim.lsp.rpc.PublicClient
---
--- Filetypes the client will attach to, if activated by `vim.lsp.enable()`.
--- If not provided, then the client will attach to all filetypes.
--- @field filetypes? string[]
---
--- Directory markers (.e.g. '.git/') where the LSP server will base its workspaceFolders,
--- rootUri, and rootPath on initialization. Unused if `root_dir` is provided.
--- @field root_markers? string[]
---
--- Directory where the LSP server will base its workspaceFolders, rootUri, and rootPath on
--- initialization. If a function, it accepts a single callback argument which must be called with
--- the value of root_dir to use. The LSP server will not be started until the callback is called.
--- @field root_dir? string|fun(cb:fun(string))
---
--- Predicate used to decide if a client should be re-used. Used on all
--- running clients. The default implementation re-uses a client if name and
--- root_dir matches.
--- @field reuse_client? fun(client: vim.lsp.Client, config: vim.lsp.ClientConfig): boolean

--- Update the configuration for an LSP client.
---
--- Use name '*' to set default configuration for all clients.
---
--- Can also be table-assigned to redefine the configuration for a client.
---
--- Examples:
---
--- - Add a root marker for all clients:
---   ```lua
---      vim.lsp.config('*', {
---          root_markers = { '.git' },
---        })
---        ```
--- - Add additional capabilities to all clients:
---   ```lua
---      vim.lsp.config('*', {
---          capabilities = {
---            textDocument = {
---              semanticTokens = {
---                multilineTokenSupport = true,
---              }
---            }
---          }
---        })
---        ```
--- - (Re-)define the configuration for clangd:
---   ```lua
---      vim.lsp.config.clangd = {
---          cmd = {
---            'clangd',
---            '--clang-tidy',
---            '--background-index',
---            '--offset-encoding=utf-8',
---          },
---          root_markers = { '.clangd', 'compile_commands.json' },
---          filetypes = { 'c', 'cpp' },
---        }
---        ```
--- - Get configuration for luals:
---   ```lua
---      local cfg = vim.lsp.config.luals
---        ```
---
--- @param name string
--- @param cfg vim.lsp.Config
--- @diagnostic disable-next-line:assign-type-mismatch
function lsp.config(name, cfg)
  local _, _ = name, cfg -- ignore unused
  -- dummy proto for docs
end

lsp._enabled_configs = {} --- @type table<string,{resolved_config:vim.lsp.Config?}>

--- If a config in vim.lsp.config() is accessed then the resolved config becomes invalid.
--- @param name string
local function invalidate_enabled_config(name)
  if name == '*' then
    for _, v in pairs(lsp._enabled_configs) do
      v.resolved_config = nil
    end
  elseif lsp._enabled_configs[name] then
    lsp._enabled_configs[name].resolved_config = nil
  end
end

--- @nodoc
--- @class vim.lsp.config
--- @field [string] vim.lsp.Config
--- @field package _configs table<string,vim.lsp.Config>
lsp.config = setmetatable({ _configs = {} }, {
  --- @param self vim.lsp.config
  --- @param name string
  --- @return vim.lsp.Config
  __index = function(self, name)
    validate('name', name, 'string')

    local rconfig = lsp._enabled_configs[name] or {}
    self._configs[name] = self._configs[name] or {}

    if not rconfig.resolved_config then
      -- Resolve configs from lsp/*.lua
      -- Calls to vim.lsp.config in lsp/* have a lower precedence than calls from other sites.
      local rtp_config = {} ---@type vim.lsp.Config
      for _, v in ipairs(api.nvim_get_runtime_file(('lsp/%s.lua'):format(name), true)) do
        local config = assert(loadfile(v))() ---@type any?
        if type(config) == 'table' then
          rtp_config = vim.tbl_deep_extend('force', rtp_config, config)
        else
          log.warn(string.format('%s does not return a table, ignoring', v))
        end
      end

      rconfig.resolved_config = vim.tbl_deep_extend(
        'force',
        lsp.config._configs['*'] or {},
        rtp_config,
        lsp.config._configs[name] or {}
      )
      rconfig.resolved_config.name = name
    end

    return rconfig.resolved_config
  end,

  --- @param self vim.lsp.config
  --- @param name string
  --- @param cfg vim.lsp.Config
  __newindex = function(self, name, cfg)
    validate('name', name, 'string')
    validate('cfg', cfg, 'table')
    invalidate_enabled_config(name)
    self._configs[name] = cfg
  end,

  --- @param self vim.lsp.config
  --- @param name string
  --- @param cfg vim.lsp.Config
  __call = function(self, name, cfg)
    validate('name', name, 'string')
    validate('cfg', cfg, 'table')
    invalidate_enabled_config(name)
    self[name] = vim.tbl_deep_extend('force', self._configs[name] or {}, cfg)
  end,
})

local lsp_enable_autocmd_id --- @type integer?

--- @param bufnr integer
local function lsp_enable_callback(bufnr)
  -- Only ever attach to buffers that represent an actual file.
  if vim.bo[bufnr].buftype ~= '' then
    return
  end

  --- @param config vim.lsp.Config
  local function can_start(config)
    if config.filetypes and not vim.tbl_contains(config.filetypes, vim.bo[bufnr].filetype) then
      return false
    elseif type(config.cmd) == 'table' and vim.fn.executable(config.cmd[1]) == 0 then
      return false
    end

    return true
  end

  --- @param config vim.lsp.Config
  local function start(config)
    return vim.lsp.start(config, {
      bufnr = bufnr,
      reuse_client = config.reuse_client,
      _root_markers = config.root_markers,
    })
  end

  for name in vim.spairs(lsp._enabled_configs) do
    local config = lsp.config[name]
    validate('cmd', config.cmd, { 'function', 'table' })
    validate('cmd', config.reuse_client, 'function', true)

    if can_start(config) then
      -- Deepcopy config so changes done in the client
      -- do not propagate back to the enabled configs.
      config = vim.deepcopy(config)

      if type(config.root_dir) == 'function' then
        ---@param root_dir string
        config.root_dir(function(root_dir)
          config.root_dir = root_dir
          vim.schedule(function()
            start(config)
          end)
        end)
      else
        start(config)
      end
    end
  end
end

--- Enable an LSP server to automatically start when opening a buffer.
---
--- Uses configuration defined with `vim.lsp.config`.
---
--- Examples:
---
--- ```lua
---   vim.lsp.enable('clangd')
---
---   vim.lsp.enable({'luals', 'pyright'})
--- ```
---
--- @param name string|string[] Name(s) of client(s) to enable.
--- @param enable? boolean `true|nil` to enable, `false` to disable.
function lsp.enable(name, enable)
  validate('name', name, { 'string', 'table' })

  local names = vim._ensure_list(name) --[[@as string[] ]]
  for _, nm in ipairs(names) do
    if nm == '*' then
      error('Invalid name')
    end
    lsp._enabled_configs[nm] = enable ~= false and {} or nil
  end

  if not next(lsp._enabled_configs) then
    if lsp_enable_autocmd_id then
      api.nvim_del_autocmd(lsp_enable_autocmd_id)
      lsp_enable_autocmd_id = nil
    end
    return
  end

  -- Only ever create autocmd once to reuse computation of config merging.
  lsp_enable_autocmd_id = lsp_enable_autocmd_id
    or api.nvim_create_autocmd('FileType', {
      group = api.nvim_create_augroup('nvim.lsp.enable', {}),
      callback = function(args)
        lsp_enable_callback(args.buf)
      end,
    })
end

--- @class vim.lsp.start.Opts
--- @inlinedoc
---
--- Predicate used to decide if a client should be re-used. Used on all
--- running clients. The default implementation re-uses a client if it has the
--- same name and if the given workspace folders (or root_dir) are all included
--- in the client's workspace folders.
--- @field reuse_client? fun(client: vim.lsp.Client, config: vim.lsp.ClientConfig): boolean
---
--- Buffer handle to attach to if starting or re-using a client (0 for current).
--- @field bufnr? integer
---
--- Whether to attach the client to a buffer (default true).
--- If set to `false`, `reuse_client` and `bufnr` will be ignored.
--- @field attach? boolean
---
--- Suppress error reporting if the LSP server fails to start (default false).
--- @field silent? boolean
---
--- @field package _root_markers? string[]

--- Create a new LSP client and start a language server or reuses an already
--- running client if one is found matching `name` and `root_dir`.
--- Attaches the current buffer to the client.
---
--- Example:
---
--- ```lua
--- vim.lsp.start({
---    name = 'my-server-name',
---    cmd = {'name-of-language-server-executable'},
---    root_dir = vim.fs.root(0, {'pyproject.toml', 'setup.py'}),
--- })
--- ```
---
--- See |vim.lsp.ClientConfig| for all available options. The most important are:
---
--- - `name` arbitrary name for the LSP client. Should be unique per language server.
--- - `cmd` command string[] or function.
--- - `root_dir` path to the project root. By default this is used to decide if an existing client
---   should be re-used. The example above uses |vim.fs.root()| to detect the root by traversing
---   the file system upwards starting from the current directory until either a `pyproject.toml`
---   or `setup.py` file is found.
--- - `workspace_folders` list of `{ uri:string, name: string }` tables specifying the project root
---   folders used by the language server. If `nil` the property is derived from `root_dir` for
---   convenience.
---
--- Language servers use this information to discover metadata like the
--- dependencies of your project and they tend to index the contents within the
--- project folder.
---
---
--- To ensure a language server is only started for languages it can handle,
--- make sure to call |vim.lsp.start()| within a |FileType| autocmd.
--- Either use |:au|, |nvim_create_autocmd()| or put the call in a
--- `ftplugin/<filetype_name>.lua` (See |ftplugin-name|)
---
--- @param config vim.lsp.ClientConfig Configuration for the server.
--- @param opts vim.lsp.start.Opts? Optional keyword arguments.
--- @return integer? client_id
function lsp.start(config, opts)
  opts = opts or {}
  local reuse_client = opts.reuse_client or reuse_client_default
  local bufnr = vim._resolve_bufnr(opts.bufnr)

  if not config.root_dir and opts._root_markers then
    config = vim.deepcopy(config)
    config.root_dir = vim.fs.root(bufnr, opts._root_markers)
  end

  for _, client in pairs(all_clients) do
    if reuse_client(client, config) then
      if opts.attach == false then
        return client.id
      end

      if lsp.buf_attach_client(bufnr, client.id) then
        return client.id
      end
      return
    end
  end

  local client_id, err = create_and_initialize_client(config)
  if err then
    if not opts.silent then
      vim.notify(err, vim.log.levels.WARN)
    end
    return
  end

  if opts.attach == false then
    return client_id
  end

  if client_id and lsp.buf_attach_client(bufnr, client_id) then
    return client_id
  end
end

--- Consumes the latest progress messages from all clients and formats them as a string.
--- Empty if there are no clients or if no new messages
---
---@return string
function lsp.status()
  local percentage = nil
  local messages = {} --- @type string[]
  for _, client in ipairs(vim.lsp.get_clients()) do
    --- @diagnostic disable-next-line:no-unknown
    for progress in client.progress do
      --- @cast progress {token: lsp.ProgressToken, value: lsp.LSPAny}
      local value = progress.value
      if type(value) == 'table' and value.kind then
        local message = value.message and (value.title .. ': ' .. value.message) or value.title
        messages[#messages + 1] = message
        if value.percentage then
          percentage = math.max(percentage or 0, value.percentage)
        end
      end
      -- else: Doesn't look like work done progress and can be in any format
      -- Just ignore it as there is no sensible way to display it
    end
  end
  local message = table.concat(messages, ', ')
  if percentage then
    return string.format('%3d%%: %s', percentage, message)
  end
  return message
end

-- Determines whether the given option can be set by `set_defaults`.
---@param bufnr integer
---@param option string
---@return boolean
local function is_empty_or_default(bufnr, option)
  if vim.bo[bufnr][option] == '' then
    return true
  end

  local info = api.nvim_get_option_info2(option, { buf = bufnr })
  ---@param e vim.fn.getscriptinfo.ret
  local scriptinfo = vim.tbl_filter(function(e)
    return e.sid == info.last_set_sid
  end, vim.fn.getscriptinfo())

  if #scriptinfo ~= 1 then
    return false
  end

  return vim.startswith(scriptinfo[1].name, vim.fn.expand('$VIMRUNTIME'))
end

---@private
---@param client vim.lsp.Client
---@param bufnr integer
function lsp._set_defaults(client, bufnr)
  if
    client:supports_method(ms.textDocument_definition) and is_empty_or_default(bufnr, 'tagfunc')
  then
    vim.bo[bufnr].tagfunc = 'v:lua.vim.lsp.tagfunc'
  end
  if
    client:supports_method(ms.textDocument_completion) and is_empty_or_default(bufnr, 'omnifunc')
  then
    vim.bo[bufnr].omnifunc = 'v:lua.vim.lsp.omnifunc'
  end
  if
    client:supports_method(ms.textDocument_rangeFormatting)
    and is_empty_or_default(bufnr, 'formatprg')
    and is_empty_or_default(bufnr, 'formatexpr')
  then
    vim.bo[bufnr].formatexpr = 'v:lua.vim.lsp.formatexpr()'
  end
  vim._with({ buf = bufnr }, function()
    if
      client:supports_method(ms.textDocument_hover)
      and is_empty_or_default(bufnr, 'keywordprg')
      and vim.fn.maparg('K', 'n', false, false) == ''
    then
      vim.keymap.set('n', 'K', function()
        vim.lsp.buf.hover()
      end, { buffer = bufnr, desc = 'vim.lsp.buf.hover()' })
    end
  end)
  if client:supports_method(ms.textDocument_diagnostic) then
    lsp.diagnostic._enable(bufnr)
  end
end

--- @deprecated
--- Starts and initializes a client with the given configuration.
--- @param config vim.lsp.ClientConfig Configuration for the server.
--- @return integer? client_id |vim.lsp.get_client_by_id()| Note: client may not be
---         fully initialized. Use `on_init` to do any actions once
---         the client has been initialized.
--- @return string? # Error message, if any
function lsp.start_client(config)
  vim.deprecate('vim.lsp.start_client()', 'vim.lsp.start()', '0.13')
  return create_and_initialize_client(config)
end

---Buffer lifecycle handler for textDocument/didSave
--- @param bufnr integer
local function text_document_did_save_handler(bufnr)
  bufnr = vim._resolve_bufnr(bufnr)
  local uri = vim.uri_from_bufnr(bufnr)
  local text = once(lsp._buf_get_full_text)
  for _, client in ipairs(lsp.get_clients({ bufnr = bufnr })) do
    local name = api.nvim_buf_get_name(bufnr)
    local old_name = changetracking._get_and_set_name(client, bufnr, name)
    if old_name and name ~= old_name then
      client:notify(ms.textDocument_didClose, {
        textDocument = {
          uri = vim.uri_from_fname(old_name),
        },
      })
      client:notify(ms.textDocument_didOpen, {
        textDocument = {
          version = 0,
          uri = uri,
          languageId = client.get_language_id(bufnr, vim.bo[bufnr].filetype),
          text = lsp._buf_get_full_text(bufnr),
        },
      })
      util.buf_versions[bufnr] = 0
    end
    local save_capability = vim.tbl_get(client.server_capabilities, 'textDocumentSync', 'save')
    if save_capability then
      local included_text --- @type string?
      if type(save_capability) == 'table' and save_capability.includeText then
        included_text = text(bufnr)
      end
      client:notify(ms.textDocument_didSave, {
        textDocument = {
          uri = uri,
        },
        text = included_text,
      })
    end
  end
end

---@param bufnr integer resolved buffer
---@param client vim.lsp.Client
local function buf_detach_client(bufnr, client)
  api.nvim_exec_autocmds('LspDetach', {
    buffer = bufnr,
    modeline = false,
    data = { client_id = client.id },
  })

  changetracking.reset_buf(client, bufnr)

  if client:supports_method(ms.textDocument_didClose) then
    local uri = vim.uri_from_bufnr(bufnr)
    local params = { textDocument = { uri = uri } }
    client:notify(ms.textDocument_didClose, params)
  end

  client.attached_buffers[bufnr] = nil

  local namespace = lsp.diagnostic.get_namespace(client.id)
  vim.diagnostic.reset(namespace, bufnr)
end

--- @type table<integer,true>
local attached_buffers = {}

--- @param bufnr integer
local function buf_attach(bufnr)
  if attached_buffers[bufnr] then
    return
  end
  attached_buffers[bufnr] = true

  local uri = vim.uri_from_bufnr(bufnr)
  local augroup = ('nvim.lsp.b_%d_save'):format(bufnr)
  local group = api.nvim_create_augroup(augroup, { clear = true })
  api.nvim_create_autocmd('BufWritePre', {
    group = group,
    buffer = bufnr,
    desc = 'vim.lsp: textDocument/willSave',
    callback = function(ctx)
      for _, client in ipairs(lsp.get_clients({ bufnr = ctx.buf })) do
        local params = {
          textDocument = {
            uri = uri,
          },
          reason = protocol.TextDocumentSaveReason.Manual, ---@type integer
        }
        if client:supports_method(ms.textDocument_willSave) then
          client:notify(ms.textDocument_willSave, params)
        end
        if client:supports_method(ms.textDocument_willSaveWaitUntil) then
          local result, err =
            client:request_sync(ms.textDocument_willSaveWaitUntil, params, 1000, ctx.buf)
          if result and result.result then
            util.apply_text_edits(result.result, ctx.buf, client.offset_encoding)
          elseif err then
            log.error(vim.inspect(err))
          end
        end
      end
    end,
  })
  api.nvim_create_autocmd('BufWritePost', {
    group = group,
    buffer = bufnr,
    desc = 'vim.lsp: textDocument/didSave handler',
    callback = function(ctx)
      text_document_did_save_handler(ctx.buf)
    end,
  })
  -- First time, so attach and set up stuff.
  api.nvim_buf_attach(bufnr, false, {
    on_lines = function(_, _, changedtick, firstline, lastline, new_lastline)
      if #lsp.get_clients({ bufnr = bufnr }) == 0 then
        -- detach if there are no clients
        return #lsp.get_clients({ bufnr = bufnr, _uninitialized = true }) == 0
      end
      util.buf_versions[bufnr] = changedtick
      changetracking.send_changes(bufnr, firstline, lastline, new_lastline)
    end,

    on_reload = function()
      local clients = lsp.get_clients({ bufnr = bufnr })
      local params = { textDocument = { uri = uri } }
      for _, client in ipairs(clients) do
        changetracking.reset_buf(client, bufnr)
        if client:supports_method(ms.textDocument_didClose) then
          client:notify(ms.textDocument_didClose, params)
        end
      end
      for _, client in ipairs(clients) do
        client:_text_document_did_open_handler(bufnr)
      end
    end,

    on_detach = function()
      local clients = lsp.get_clients({ bufnr = bufnr, _uninitialized = true })
      for _, client in ipairs(clients) do
        buf_detach_client(bufnr, client)
      end
      attached_buffers[bufnr] = nil
      util.buf_versions[bufnr] = nil
    end,

    -- TODO if we know all of the potential clients ahead of time, then we
    -- could conditionally set this.
    --      utf_sizes = size_index > 1;
    utf_sizes = true,
  })
end

--- Implements the `textDocument/did…` notifications required to track a buffer
--- for any language server.
---
--- Without calling this, the server won't be notified of changes to a buffer.
---
---@param bufnr (integer) Buffer handle, or 0 for current
---@param client_id (integer) Client id
---@return boolean success `true` if client was attached successfully; `false` otherwise
function lsp.buf_attach_client(bufnr, client_id)
  validate('bufnr', bufnr, 'number', true)
  validate('client_id', client_id, 'number')
  bufnr = vim._resolve_bufnr(bufnr)
  if not api.nvim_buf_is_loaded(bufnr) then
    log.warn(string.format('buf_attach_client called on unloaded buffer (id: %d): ', bufnr))
    return false
  end

  local client = lsp.get_client_by_id(client_id)
  if not client then
    return false
  end

  buf_attach(bufnr)

  if client.attached_buffers[bufnr] then
    return true
  end

  client.attached_buffers[bufnr] = true

  -- This is our first time attaching this client to this buffer.
  -- Send didOpen for the client if it is initialized. If it isn't initialized
  -- then it will send didOpen on initialize.
  if client.initialized then
    client:on_attach(bufnr)
  end
  return true
end

--- Detaches client from the specified buffer.
--- Note: While the server is notified that the text document (buffer)
--- was closed, it is still able to send notifications should it ignore this notification.
---
---@param bufnr integer Buffer handle, or 0 for current
---@param client_id integer Client id
function lsp.buf_detach_client(bufnr, client_id)
  validate('bufnr', bufnr, 'number', true)
  validate('client_id', client_id, 'number')
  bufnr = vim._resolve_bufnr(bufnr)

  local client = all_clients[client_id]
  if not client or not client.attached_buffers[bufnr] then
    vim.notify(
      string.format(
        'Buffer (id: %d) is not attached to client (id: %d). Cannot detach.',
        bufnr,
        client_id
      )
    )
    return
  else
    buf_detach_client(bufnr, client)
  end
end

--- Checks if a buffer is attached for a particular client.
---
---@param bufnr (integer) Buffer handle, or 0 for current
---@param client_id (integer) the client id
function lsp.buf_is_attached(bufnr, client_id)
  return lsp.get_clients({ bufnr = bufnr, id = client_id, _uninitialized = true })[1] ~= nil
end

--- Gets a client by id, or nil if the id is invalid.
--- The returned client may not yet be fully initialized.
---
---@param client_id integer client id
---
---@return (nil|vim.lsp.Client) client rpc object
function lsp.get_client_by_id(client_id)
  return all_clients[client_id]
end

--- Returns list of buffers attached to client_id.
---
---@param client_id integer client id
---@return integer[] buffers list of buffer ids
function lsp.get_buffers_by_client_id(client_id)
  local client = all_clients[client_id]
  return client and vim.tbl_keys(client.attached_buffers) or {}
end

--- Stops a client(s).
---
--- You can also use the `stop()` function on a |vim.lsp.Client| object.
--- To stop all clients:
---
--- ```lua
--- vim.lsp.stop_client(vim.lsp.get_clients())
--- ```
---
--- By default asks the server to shutdown, unless stop was requested
--- already for this client, then force-shutdown is attempted.
---
---@param client_id integer|integer[]|vim.lsp.Client[] id, list of id's, or list of |vim.lsp.Client| objects
---@param force? boolean shutdown forcefully
function lsp.stop_client(client_id, force)
  --- @type integer[]|vim.lsp.Client[]
  local ids = type(client_id) == 'table' and client_id or { client_id }
  for _, id in ipairs(ids) do
    if type(id) == 'table' then
      if id.stop then
        id:stop(force)
      end
    else
      --- @cast id -vim.lsp.Client
      local client = all_clients[id]
      if client then
        client:stop(force)
      end
    end
  end
end

--- Key-value pairs used to filter the returned clients.
--- @class vim.lsp.get_clients.Filter
--- @inlinedoc
---
--- Only return clients with the given id
--- @field id? integer
---
--- Only return clients attached to this buffer
--- @field bufnr? integer
---
--- Only return clients with the given name
--- @field name? string
---
--- Only return clients supporting the given method
--- @field method? string
---
--- Also return uninitialized clients.
--- @field package _uninitialized? boolean

--- Get active clients.
---
---@param filter? vim.lsp.get_clients.Filter
---@return vim.lsp.Client[]: List of |vim.lsp.Client| objects
function lsp.get_clients(filter)
  validate('filter', filter, 'table', true)

  filter = filter or {}

  local clients = {} --- @type vim.lsp.Client[]

  local bufnr = filter.bufnr and vim._resolve_bufnr(filter.bufnr)

  for _, client in pairs(all_clients) do
    if
      client
      and (filter.id == nil or client.id == filter.id)
      and (filter.bufnr == nil or client.attached_buffers[bufnr])
      and (filter.name == nil or client.name == filter.name)
      and (filter.method == nil or client:supports_method(filter.method, filter.bufnr))
      and (filter._uninitialized or client.initialized)
    then
      clients[#clients + 1] = client
    end
  end
  return clients
end

---@private
---@deprecated
function lsp.get_active_clients(filter)
  vim.deprecate('vim.lsp.get_active_clients()', 'vim.lsp.get_clients()', '0.12')
  return lsp.get_clients(filter)
end

api.nvim_create_autocmd('VimLeavePre', {
  desc = 'vim.lsp: exit handler',
  callback = function()
    local active_clients = lsp.get_clients()
    log.info('exit_handler', active_clients)
    for _, client in pairs(all_clients) do
      client:stop()
    end

    local timeouts = {} --- @type table<integer,integer>
    local max_timeout = 0
    local send_kill = false

    for client_id, client in pairs(active_clients) do
      local timeout = client.flags.exit_timeout
      if timeout then
        send_kill = true
        timeouts[client_id] = timeout
        max_timeout = math.max(timeout, max_timeout)
      end
    end

    local poll_time = 50

    local function check_clients_closed()
      for client_id, timeout in pairs(timeouts) do
        timeouts[client_id] = timeout - poll_time
      end

      for client_id, _ in pairs(active_clients) do
        if timeouts[client_id] ~= nil and timeouts[client_id] > 0 then
          return false
        end
      end
      return true
    end

    if send_kill then
      if not vim.wait(max_timeout, check_clients_closed, poll_time) then
        for client_id, client in pairs(active_clients) do
          if timeouts[client_id] ~= nil then
            client:stop(true)
          end
        end
      end
    end
  end,
})

---@private
--- Sends an async request for all active clients attached to the
--- buffer.
---
---@param bufnr (integer) Buffer handle, or 0 for current.
---@param method (string) LSP method name
---@param params? table|(fun(client: vim.lsp.Client, bufnr: integer): table?) Parameters to send to the server
---@param handler? lsp.Handler See |lsp-handler|
---       If nil, follows resolution strategy defined in |lsp-handler-configuration|
---@param on_unsupported? fun()
---       The function to call when the buffer has no clients that support the given method.
---       Defaults to an `ERROR` level notification.
---@return table<integer, integer> client_request_ids Map of client-id:request-id pairs
---for all successful requests.
---@return function _cancel_all_requests Function which can be used to
---cancel all the requests. You could instead
---iterate all clients and call their `cancel_request()` methods.
function lsp.buf_request(bufnr, method, params, handler, on_unsupported)
  validate('bufnr', bufnr, 'number', true)
  validate('method', method, 'string')
  validate('handler', handler, 'function', true)
  validate('on_unsupported', on_unsupported, 'function', true)

  bufnr = vim._resolve_bufnr(bufnr)
  local method_supported = false
  local clients = lsp.get_clients({ bufnr = bufnr })
  local client_request_ids = {} --- @type table<integer,integer>
  for _, client in ipairs(clients) do
    if client:supports_method(method, bufnr) then
      method_supported = true

      local cparams = type(params) == 'function' and params(client, bufnr) or params --[[@as table?]]
      local request_success, request_id = client:request(method, cparams, handler, bufnr)
      -- This could only fail if the client shut down in the time since we looked
      -- it up and we did the request, which should be rare.
      if request_success then
        client_request_ids[client.id] = request_id
      end
    end
  end

  -- if has client but no clients support the given method, notify the user
  if next(clients) and not method_supported then
    if on_unsupported == nil then
      vim.notify(lsp._unsupported_method(method), vim.log.levels.ERROR)
    else
      on_unsupported()
    end
    vim.cmd.redraw()
    return {}, function() end
  end

  local function _cancel_all_requests()
    for client_id, request_id in pairs(client_request_ids) do
      local client = all_clients[client_id]
      client:cancel_request(request_id)
    end
  end

  return client_request_ids, _cancel_all_requests
end

--- Sends an async request for all active clients attached to the buffer and executes the `handler`
--- callback with the combined result.
---
---@param bufnr (integer) Buffer handle, or 0 for current.
---@param method (string) LSP method name
---@param params? table|(fun(client: vim.lsp.Client, bufnr: integer): table?) Parameters to send to the server.
---               Can also be passed as a function that returns the params table for cases where
---               parameters are specific to the client.
---@param handler lsp.MultiHandler (function)
--- Handler called after all requests are completed. Server results are passed as
--- a `client_id:result` map.
---@return function cancel Function that cancels all requests.
function lsp.buf_request_all(bufnr, method, params, handler)
  local results = {} --- @type table<integer,{err: lsp.ResponseError?, result: any}>
  local remaining --- @type integer?

  local _, cancel = lsp.buf_request(bufnr, method, params, function(err, result, ctx, config)
    if not remaining then
      -- Calculate as late as possible in case a client is removed during the request
      remaining = #lsp.get_clients({ bufnr = bufnr, method = method })
    end

    -- The error key is deprecated and will be removed in 0.13
    results[ctx.client_id] = { err = err, error = err, result = result }
    remaining = remaining - 1

    if remaining == 0 then
      handler(results, ctx, config)
    end
  end)

  return cancel
end

--- Sends a request to all server and waits for the response of all of them.
---
--- Calls |vim.lsp.buf_request_all()| but blocks Nvim while awaiting the result.
--- Parameters are the same as |vim.lsp.buf_request_all()| but the result is
--- different. Waits a maximum of {timeout_ms}.
---
---@param bufnr integer Buffer handle, or 0 for current.
---@param method string LSP method name
---@param params table? Parameters to send to the server
---@param timeout_ms integer? Maximum time in milliseconds to wait for a result.
---                           (default: `1000`)
---@return table<integer, {error: lsp.ResponseError?, result: any}>? result Map of client_id:request_result.
---@return string? err On timeout, cancel, or error, `err` is a string describing the failure reason, and `result` is nil.
function lsp.buf_request_sync(bufnr, method, params, timeout_ms)
  local request_results ---@type table

  local cancel = lsp.buf_request_all(bufnr, method, params, function(it)
    request_results = it
  end)

  local wait_result, reason = vim.wait(timeout_ms or 1000, function()
    return request_results ~= nil
  end, 10)

  if not wait_result then
    cancel()
    return nil, wait_result_reason[reason]
  end

  return request_results
end

--- Send a notification to a server
---@param bufnr (integer|nil) The number of the buffer
---@param method (string) Name of the request method
---@param params (any) Arguments to send to the server
---
---@return boolean success true if any client returns true; false otherwise
function lsp.buf_notify(bufnr, method, params)
  validate('bufnr', bufnr, 'number', true)
  validate('method', method, 'string')
  local resp = false
  for _, client in ipairs(lsp.get_clients({ bufnr = bufnr })) do
    if client.rpc.notify(method, params) then
      resp = true
    end
  end
  return resp
end

--- Implements 'omnifunc' compatible LSP completion.
---
---@see |complete-functions|
---@see |complete-items|
---@see |CompleteDone|
---
---@param findstart integer 0 or 1, decides behavior
---@param base integer findstart=0, text to match against
---
---@return integer|table Decided by {findstart}:
--- - findstart=0: column where the completion starts, or -2 or -3
--- - findstart=1: list of matches (actually just calls |complete()|)
function lsp.omnifunc(findstart, base)
  return vim.lsp.completion._omnifunc(findstart, base)
end

--- @class vim.lsp.formatexpr.Opts
--- @inlinedoc
---
--- The timeout period for the formatting request.
--- (default: 500ms).
--- @field timeout_ms integer

--- Provides an interface between the built-in client and a `formatexpr` function.
---
--- Currently only supports a single client. This can be set via
--- `setlocal formatexpr=v:lua.vim.lsp.formatexpr()` or (more typically) in `on_attach`
--- via `vim.bo[bufnr].formatexpr = 'v:lua.vim.lsp.formatexpr(#{timeout_ms:250})'`.
---
---@param opts? vim.lsp.formatexpr.Opts
function lsp.formatexpr(opts)
  opts = opts or {}
  local timeout_ms = opts.timeout_ms or 500

  if vim.list_contains({ 'i', 'R', 'ic', 'ix' }, vim.fn.mode()) then
    -- `formatexpr` is also called when exceeding `textwidth` in insert mode
    -- fall back to internal formatting
    return 1
  end

  local start_lnum = vim.v.lnum
  local end_lnum = start_lnum + vim.v.count - 1

  if start_lnum <= 0 or end_lnum <= 0 then
    return 0
  end
  local bufnr = api.nvim_get_current_buf()
  for _, client in pairs(lsp.get_clients({ bufnr = bufnr })) do
    if client:supports_method(ms.textDocument_rangeFormatting) then
      local params = util.make_formatting_params()
      local end_line = vim.fn.getline(end_lnum) --[[@as string]]
      local end_col = vim.str_utfindex(end_line, client.offset_encoding)
      --- @cast params +lsp.DocumentRangeFormattingParams
      params.range = {
        start = {
          line = start_lnum - 1,
          character = 0,
        },
        ['end'] = {
          line = end_lnum - 1,
          character = end_col,
        },
      }
      local response =
        client:request_sync(ms.textDocument_rangeFormatting, params, timeout_ms, bufnr)
      if response and response.result then
        lsp.util.apply_text_edits(response.result, bufnr, client.offset_encoding)
        return 0
      end
    end
  end

  -- do not run builtin formatter.
  return 0
end

--- Provides an interface between the built-in client and 'tagfunc'.
---
--- When used with normal mode commands (e.g. |CTRL-]|) this will invoke
--- the "textDocument/definition" LSP method to find the tag under the cursor.
--- Otherwise, uses "workspace/symbol". If no results are returned from
--- any LSP servers, falls back to using built-in tags.
---
---@param pattern string Pattern used to find a workspace symbol
---@param flags string See |tag-function|
---
---@return table[] tags A list of matching tags
function lsp.tagfunc(pattern, flags)
  return vim.lsp._tagfunc(pattern, flags)
end

--- Provides an interface between the built-in client and a `foldexpr` function.
---
--- To use, check for the "textDocument/foldingRange" capability in an
--- |LspAttach| autocommand. Example:
---
--- ```lua
--- vim.api.nvim_create_autocmd('LspAttach', {
---   callback = function(args)
---     local client = vim.lsp.get_client_by_id(args.data.client_id)
---     if client:supports_method('textDocument/foldingRange') then
---       local win = vim.api.nvim_get_current_win()
---       vim.wo[win][0].foldmethod = 'expr'
---       vim.wo[win][0].foldexpr = 'v:lua.vim.lsp.foldexpr()'
---     end
---   end,
--- })
--- ```
---
---@param lnum integer line number
function lsp.foldexpr(lnum)
  return vim.lsp._folding_range.foldexpr(lnum)
end

--- Close all {kind} of folds in the the window with {winid}.
---
--- To automatically fold imports when opening a file, you can use an autocmd:
---
--- ```lua
--- vim.api.nvim_create_autocmd('LspNotify', {
---   callback = function(args)
---     if args.data.method == 'textDocument/didOpen' then
---       vim.lsp.foldclose('imports', vim.fn.bufwinid(args.buf))
---     end
---   end,
--- })
--- ```
---
---@param kind lsp.FoldingRangeKind Kind to close, one of "comment", "imports" or "region".
---@param winid? integer Defaults to the current window.
function lsp.foldclose(kind, winid)
  return vim.lsp._folding_range.foldclose(kind, winid)
end

--- Provides a `foldtext` function that shows the `collapsedText` retrieved,
--- defaults to the first folded line if `collapsedText` is not provided.
function lsp.foldtext()
  return vim.lsp._folding_range.foldtext()
end

---Checks whether a client is stopped.
---
---@param client_id (integer)
---@return boolean stopped true if client is stopped, false otherwise.
function lsp.client_is_stopped(client_id)
  assert(client_id, 'missing client_id param')
  return not all_clients[client_id]
end

--- Gets a map of client_id:client pairs for the given buffer, where each value
--- is a |vim.lsp.Client| object.
---
---@param bufnr (integer|nil): Buffer handle, or 0 for current
---@return table result is table of (client_id, client) pairs
---@deprecated Use |vim.lsp.get_clients()| instead.
function lsp.buf_get_clients(bufnr)
  vim.deprecate('vim.lsp.buf_get_clients()', 'vim.lsp.get_clients()', '0.12')
  local result = {} --- @type table<integer,vim.lsp.Client>
  for _, client in ipairs(lsp.get_clients({ bufnr = vim._resolve_bufnr(bufnr) })) do
    result[client.id] = client
  end
  return result
end

--- Log level dictionary with reverse lookup as well.
---
--- Can be used to lookup the number from the name or the
--- name from the number.
--- Levels by name: "TRACE", "DEBUG", "INFO", "WARN", "ERROR", "OFF"
--- Level numbers begin with "TRACE" at 0
--- @nodoc
lsp.log_levels = log.levels

--- Sets the global log level for LSP logging.
---
--- Levels by name: "TRACE", "DEBUG", "INFO", "WARN", "ERROR", "OFF"
---
--- Level numbers begin with "TRACE" at 0
---
--- Use `lsp.log_levels` for reverse lookup.
---
---@see |vim.lsp.log_levels|
---
---@param level (integer|string) the case insensitive level name or number
function lsp.set_log_level(level)
  if type(level) == 'string' or type(level) == 'number' then
    log.set_level(level)
  else
    error(string.format('Invalid log level: %q', level))
  end
end

--- Gets the path of the logfile used by the LSP client.
---@return string path to log file
function lsp.get_log_path()
  return log.get_filename()
end

---@private
--- Invokes a function for each LSP client attached to a buffer.
---
---@param bufnr integer Buffer number
---@param fn function Function to run on each client attached to buffer
---                   {bufnr}. The function takes the client, client ID, and
---                   buffer number as arguments.
---@deprecated use lsp.get_clients({ bufnr = bufnr }) with regular loop
function lsp.for_each_buffer_client(bufnr, fn)
  vim.deprecate(
    'vim.lsp.for_each_buffer_client()',
    'lsp.get_clients({ bufnr = bufnr }) with regular loop',
    '0.12'
  )
  bufnr = vim._resolve_bufnr(bufnr)

  for _, client in pairs(lsp.get_clients({ bufnr = bufnr })) do
    fn(client, client.id, bufnr)
  end
end

--- @deprecated
--- Function to manage overriding defaults for LSP handlers.
---@param handler (lsp.Handler) See |lsp-handler|
---@param override_config (table) Table containing the keys to override behavior of the {handler}
function lsp.with(handler, override_config)
  return function(err, result, ctx, config)
    return handler(err, result, ctx, vim.tbl_deep_extend('force', config or {}, override_config))
  end
end

--- Registry for client side commands.
--- This is an extension point for plugins to handle custom commands which are
--- not part of the core language server protocol specification.
---
--- The registry is a table where the key is a unique command name,
--- and the value is a function which is called if any LSP action
--- (code action, code lenses, ...) triggers the command.
---
--- If an LSP response contains a command for which no matching entry is
--- available in this registry, the command will be executed via the LSP server
--- using `workspace/executeCommand`.
---
--- The first argument to the function will be the `Command`:
---   Command
---     title: String
---     command: String
---     arguments?: any[]
---
--- The second argument is the `ctx` of |lsp-handler|
--- @type table<string,function>
lsp.commands = setmetatable({}, {
  __newindex = function(tbl, key, value)
    assert(type(key) == 'string', 'The key for commands in `vim.lsp.commands` must be a string')
    assert(type(value) == 'function', 'Command added to `vim.lsp.commands` must be a function')
    rawset(tbl, key, value)
  end,
})

return lsp