path: root/runtime/lua/vim/lsp/completion.lua

--- @brief
--- The `vim.lsp.completion` module enables insert-mode completion driven by an LSP server. Call
--- `enable()` to make it available through Nvim builtin completion (via the |CompleteDone| event).
--- Specify `autotrigger=true` to activate "auto-completion" when you type any of the server-defined
--- `triggerCharacters`. Use CTRL-Y to select an item from the completion menu. |complete_CTRL-Y|
---
--- Example: activate LSP-driven auto-completion:
--- ```lua
--- -- Works best if 'completeopt' has "noselect".
--- -- Use CTRL-Y to select an item. |complete_CTRL-Y|
--- vim.cmd[[set completeopt+=menuone,noselect,popup]]
--- vim.lsp.start({
---   name = 'ts_ls',
---   cmd = …,
---   on_attach = function(client, bufnr)
---     vim.lsp.completion.enable(true, client.id, bufnr, {
---       autotrigger = true,
---       convert = function(item)
---         return { abbr = item.label:gsub('%b()', '') }
---       end,
---     })
---   end,
--- })
--- ```
---
--- [lsp-autocompletion]()
---
--- The LSP `triggerCharacters` field decides when to trigger autocompletion. If you want to trigger
--- on EVERY keypress you can either:
--- - Extend `client.server_capabilities.completionProvider.triggerCharacters` on `LspAttach`,
---   before you call `vim.lsp.completion.enable(… {autotrigger=true})`. See the |lsp-attach| example.
--- - Call `vim.lsp.completion.get()` from an |InsertCharPre| autocommand.

local M = {}

local api = vim.api
local lsp = vim.lsp
local protocol = lsp.protocol

local rtt_ms = 50.0
local ns_to_ms = 0.000001

--- @alias vim.lsp.CompletionResult lsp.CompletionList | lsp.CompletionItem[]

-- TODO(mariasolos): Remove this declaration once we figure out a better way to handle
-- literal/anonymous types (see https://github.com/neovim/neovim/pull/27542/files#r1495259331).
--- @nodoc
--- @class lsp.ItemDefaults
--- @field editRange lsp.Range | { insert: lsp.Range, replace: lsp.Range } | nil
--- @field insertTextFormat lsp.InsertTextFormat?
--- @field insertTextMode lsp.InsertTextMode?
--- @field data any

--- @nodoc
--- @class vim.lsp.completion.BufHandle
--- @field clients table<integer, vim.lsp.Client>
--- @field triggers table<string, vim.lsp.Client[]>
--- @field convert? fun(item: lsp.CompletionItem): table

--- @type table<integer, vim.lsp.completion.BufHandle>
local buf_handles = {}

--- @nodoc
--- @class vim.lsp.completion.Context
local Context = {
  cursor = nil, --- @type [integer, integer]?
  last_request_time = nil, --- @type integer?
  pending_requests = {}, --- @type function[]
  isIncomplete = false,
  -- Handles "completionItem/resolve".
  resolve_handler = nil, --- @type CompletionResolver?
}

--- @nodoc
function Context:cancel_pending()
  for _, cancel in ipairs(self.pending_requests) do
    cancel()
  end

  self.pending_requests = {}
end

--- @nodoc
function Context:reset()
  -- Note that the cursor isn't reset here, it needs to survive a `CompleteDone` event.
  self.isIncomplete = false
  self.last_request_time = nil
  self:cancel_pending()
  if self.resolve_handler then
    self.resolve_handler:cleanup()
    self.resolve_handler = nil
  end
end

--- @type uv.uv_timer_t?
local completion_timer = nil

--- @return uv.uv_timer_t
local function new_timer()
  return (assert(vim.uv.new_timer()))
end

local function reset_timer()
  if completion_timer then
    completion_timer:stop()
    completion_timer:close()
  end

  completion_timer = nil
end

--- @param window integer
--- @param warmup integer
--- @return fun(sample: integer): integer
local function exp_avg(window, warmup)
  local count = 0
  local sum = 0
  local value = 0.0

  return function(sample)
    if count < warmup then
      count = count + 1
      sum = sum + sample
      value = sum / count
    else
      local factor = 2.0 / (window + 1)
      value = value * (1 - factor) + sample * factor
    end
    return value
  end
end
local compute_new_average = exp_avg(10, 10)

--- Calculates the adaptive debounce time based on the elapsed time since the last request.
---
--- @param last_request_time integer?
--- @param current_rtt_ms number
--- @return integer
local function adaptive_debounce(last_request_time, current_rtt_ms)
  if not last_request_time then
    return current_rtt_ms
  end
  local ms_since_request = (vim.uv.hrtime() - last_request_time) * ns_to_ms
  return math.max((ms_since_request - current_rtt_ms) * -1, 0)
end

--- @param flag string
--- @return boolean
local function has_completeopt(flag)
  return vim.list_contains(vim.opt.completeopt:get(), flag)
end

--- @param input string Unparsed snippet
--- @return string # Parsed snippet if successful, else returns its input
local function parse_snippet(input)
  local ok, parsed = pcall(function()
    return lsp._snippet_grammar.parse(input)
  end)
  return ok and tostring(parsed) or input
end

--- @param item lsp.CompletionItem
local function apply_snippet(item)
  if item.textEdit then
    vim.snippet.expand(item.textEdit.newText)
  elseif item.insertText then
    vim.snippet.expand(item.insertText)
  end
end

--- Returns text that should be inserted when a selecting completion item. The
--- precedence is as follows: textEdit.newText > insertText > label
---
--- See https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textDocument_completion
---
--- @param item lsp.CompletionItem
--- @param prefix string
--- @param match fun(text: string, prefix: string):boolean
--- @return string
local function get_completion_word(item, prefix, match)
  if item.insertTextFormat == protocol.InsertTextFormat.Snippet then