feat: add llm translation service

README.md

@@ -91,7 +91,7 @@ use {
 ```lua
 require('comment-translate').setup({
   target_language = 'ja',  -- Target language (default: auto-detected from system locale, fallback 'en')
-  translate_service = 'google',  -- Currently only 'google' is supported
+  translate_service = 'google',  -- 'google' or 'llm'
   hover = {
     enabled = true,  -- Enable hover translation
     delay = 500,  -- Additional delay (ms) after CursorHold before showing hover
@@ -109,6 +109,14 @@ require('comment-translate').setup({
     comment = true,  -- Include comments as translation targets
     string = true,  -- Include strings as translation targets
   },
+  llm = {
+    provider = 'openai',  -- 'openai' | 'anthropic' | 'gemini' | 'ollama'
+    api_key = nil,  -- Required except provider='ollama' (can also use provider-specific env vars)
+    model = 'gpt-5.2',
+    endpoint = nil,  -- Optional custom endpoint (default depends on provider)
+    system_prompt = nil,  -- Optional custom system prompt
+    timeout = 20,  -- curl max-time in seconds
+  },
   keymaps = {
     hover = '<leader>th',  -- Hover translation
     hover_manual = '<leader>tc',  -- Manual hover trigger (when auto is disabled)
@@ -122,6 +130,52 @@ require('comment-translate').setup({
 
 * **target_language**: Automatically detected from system locale (`LANG`, `LANGUAGE`, `LC_ALL`) or Vim language settings. Falls back to `'en'` if detection fails.
 * **hover.delay**: Applied after the `CursorHold` event. Total delay is `updatetime` (Neovim option) plus `hover.delay`.
+* **translate_service = 'llm'**: Supports `openai`, `anthropic`, `gemini`, and `ollama`.
+* **API key env vars**:
+  * `openai`: `OPENAI_API_KEY`
+  * `anthropic`: `ANTHROPIC_API_KEY`
+  * `gemini`: `GEMINI_API_KEY`
+  * `ollama`: API key not required
+
+### LLM Translation Example
+
+```lua
+require('comment-translate').setup({
+  translate_service = 'llm',
+  target_language = 'ja',
+  llm = {
+    provider = 'openai',
+    api_key = vim.env.OPENAI_API_KEY, -- or a literal key string
+    model = 'gpt-5.2',
+  },
+})
+```
+
+### Provider Examples
+
+```lua
+-- Anthropic
+llm = {
+  provider = 'anthropic',
+  model = 'claude-sonnet-4-0',
+  api_key = vim.env.ANTHROPIC_API_KEY,
+}
+
+-- Gemini
+llm = {
+  provider = 'gemini',
+  model = 'gemini-2.5-flash',
+  api_key = vim.env.GEMINI_API_KEY,
+}
+
+-- Ollama (local)
+llm = {
+  provider = 'ollama',
+  model = 'translategemma:4b',
+  endpoint = 'http://localhost:11434/api/chat', -- optional (default shown)
+}
+
+```
 
 ## Commands
 
@@ -137,7 +191,7 @@ require('comment-translate').setup({
 
 This plugin prioritizes transparency. To provide real-time translation, text is sent to an external translation service.
 
-* **External transmission**: Translation uses the unofficial Google Translate HTTP endpoint (`translate.googleapis.com`) via `curl`.
+* **External transmission**: Translation sends text to the configured external service (`google` or `llm`) via `curl`.
 * **What is sent**: The selected text or detected comment/string content. If it contains **personal data**, **credentials**, **internal code**, or other sensitive information, it may be transmitted outside your environment.
 * **Cache behavior**: The built-in cache is **in-memory only**. No files are written by the plugin, and the cache is cleared when Neovim exits.
 * **Control**: Automatic hover translation can be disabled, and all translation features are user-controlled.
@@ -177,6 +231,12 @@ make fmt
 make fmt-check
 ```
 
+* Run tests:
+
+```sh
+make test
+```
+
 ## License
 
 MIT

doc/comment-translate.txt

@@ -14,17 +14,17 @@ REQUIREMENTS                                    *comment-translate-requirements*
 - nvim-treesitter (recommended)
 - curl command (for translation API)
 - Internet connection
-- Translation uses the unofficial Google Translate HTTP endpoint via curl.
-  Network policy changes (proxy/firewall) or upstream API changes may break
-  translation; inform users in restricted environments.
+- Translation uses the configured external service (`google` or `llm`) via
+  curl. Network policy changes (proxy/firewall) or upstream API changes may
+  break translation; inform users in restricted environments.
 
 PRIVACY / DATA HANDLING                          *comment-translate-privacy*
 
 {comment-translate.nvim} sends the text you translate (comments, strings, or
 visual selections) to an external translation service over the network.
 
-- External transmission: Translation uses the unofficial Google Translate HTTP
-  endpoint (translate.googleapis.com) via curl.
+- External transmission: Translation sends text to the configured external
+  service (`google` or `llm`) via curl.
 - What is sent: The target text content itself. If it contains personal data,
   credentials, internal code, or other sensitive information, it may be sent
   outside your environment.
@@ -106,9 +106,39 @@ Options:
     Default: System locale or 'en'
 
 *comment-translate.translate_service*
-    Translation service to use: currently only 'google' is available.
+    Translation service to use: 'google' or 'llm'.
     Default: 'google'
 
+*comment-translate.llm.provider*
+    LLM provider when translate_service = 'llm'.
+    Supported: 'openai', 'anthropic', 'gemini', 'ollama'
+    Default: 'openai'
+
+*comment-translate.llm.api_key*
+    API key for LLM translation service.
+    Required for all providers except 'ollama'.
+    Environment variable fallback:
+      - openai: OPENAI_API_KEY
+      - anthropic: ANTHROPIC_API_KEY
+      - gemini: GEMINI_API_KEY
+    Default: nil
+
+*comment-translate.llm.model*
+    Model name for LLM translation.
+    Default: 'gpt-5.2'
+
+*comment-translate.llm.endpoint*
+    Optional endpoint override. If nil, provider-specific defaults are used.
+    Default: nil
+
+*comment-translate.llm.system_prompt*
+    Optional system prompt for translation behavior.
+    Default: nil (plugin uses internal prompt)
+
+*comment-translate.llm.timeout*
+    HTTP timeout (seconds) used by curl for LLM translation requests.
+    Default: 20
+
 *comment-translate.hover.enabled*
     Enable automatic hover translation.
     Default: true

lua/comment-translate/config.lua

@@ -6,6 +6,7 @@
 ---@field cache CommentTranslateCacheConfig
 ---@field max_length number
 ---@field targets CommentTranslateTargetsConfig
+---@field llm CommentTranslateLLMConfig
 
 ---@class CommentTranslateHoverConfig
 ---@field enabled boolean
@@ -23,13 +24,31 @@
 ---@field comment boolean
 ---@field string boolean
 
+---@class CommentTranslateLLMConfig
+---@field provider string
+---@field api_key string?
+---@field model string
+---@field endpoint string?
+---@field system_prompt string?
+---@field timeout number
+
 ---@class CommentTranslateKeymapsConfig
 ---@field hover? string|false
 ---@field hover_manual? string|false Keymap for manual hover when auto-hover is disabled
 ---@field replace? string|false
 ---@field toggle? string|false
 
 local M = {}
+local SUPPORTED_SERVICES = {
+  google = true,
+  llm = true,
+}
+local SUPPORTED_LLM_PROVIDERS = {
+  openai = true,
+  anthropic = true,
+  gemini = true,
+  ollama = true,
+}
 
 ---@return string
 local function get_default_language()
@@ -67,6 +86,14 @@ local default_config = {
     comment = true,
     string = true,
   },
+  llm = {
+    provider = 'openai',
+    api_key = nil,
+    model = 'gpt-5.2',
+    endpoint = nil,
+    system_prompt = nil,
+    timeout = 20,
+  },
   keymaps = {
     hover = '<leader>th',
     hover_manual = '<leader>tc',
@@ -102,9 +129,21 @@ local function validate(user_config)
     cache = { user_config.cache, 'table', true },
     max_length = { user_config.max_length, 'number', true },
     targets = { user_config.targets, 'table', true },
+    llm = { user_config.llm, 'table', true },
     keymaps = { user_config.keymaps, 'table', true },
   })
 
+  if user_config.translate_service and not SUPPORTED_SERVICES[user_config.translate_service] then
+    vim.notify(
+      string.format(
+        "comment-translate: unsupported translate_service '%s', defaulting to 'google'",
+        tostring(user_config.translate_service)
+      ),
+      vim.log.levels.WARN
+    )
+    user_config.translate_service = 'google'
+  end
+
   if user_config.hover then
     warn_unknown('hover', user_config.hover, { enabled = true, delay = true, auto = true })
     vim.validate({
@@ -145,6 +184,44 @@ local function validate(user_config)
     })
   end
 
+  if user_config.llm then
+    warn_unknown('llm', user_config.llm, {
+      provider = true,
+      api_key = true,
+      model = true,
+      endpoint = true,
+      system_prompt = true,
+      timeout = true,
+    })
+    vim.validate({
+      ['llm.provider'] = { user_config.llm.provider, 'string', true },
+      ['llm.api_key'] = { user_config.llm.api_key, 'string', true },
+      ['llm.model'] = { user_config.llm.model, 'string', true },
+      ['llm.endpoint'] = { user_config.llm.endpoint, 'string', true },
+      ['llm.system_prompt'] = { user_config.llm.system_prompt, 'string', true },
+      ['llm.timeout'] = { user_config.llm.timeout, 'number', true },
+    })
+
+    if user_config.llm.provider and not SUPPORTED_LLM_PROVIDERS[user_config.llm.provider] then
+      vim.notify(
+        string.format(
+          "comment-translate: unsupported llm.provider '%s', defaulting to 'openai'",
+          tostring(user_config.llm.provider)
+        ),
+        vim.log.levels.WARN
+      )
+      user_config.llm.provider = 'openai'
+    end
+
+    if user_config.llm.timeout and user_config.llm.timeout <= 0 then
+      vim.notify(
+        'comment-translate: llm.timeout must be > 0, defaulting to 20',
+        vim.log.levels.WARN
+      )
+      user_config.llm.timeout = 20
+    end
+  end
+
   if user_config.keymaps then
     warn_unknown(
       'keymaps',

lua/comment-translate/health.lua

@@ -2,6 +2,7 @@
 ---Run with :checkhealth comment-translate
 
 local M = {}
+local utils = require('comment-translate.utils')
 
 ---@param module_name string
 ---@return boolean
@@ -64,6 +65,40 @@ function M.check()
       vim.health.ok('Plugin is configured')
       vim.health.info('Target language: ' .. (config.config.target_language or 'not set'))
       vim.health.info('Translate service: ' .. (config.config.translate_service or 'not set'))
+
+      if config.config.translate_service == 'llm' then
+        local provider = (config.config.llm and config.config.llm.provider) or 'openai'
+        vim.health.info('LLM provider: ' .. provider)
+
+        if provider == 'ollama' then
+          vim.health.ok('LLM API key is not required for ollama provider')
+        else
+          local env_keys = {
+            openai = { 'OPENAI_API_KEY' },
+            anthropic = { 'ANTHROPIC_API_KEY' },
+            gemini = { 'GEMINI_API_KEY' },
+          }
+          local configured = config.config.llm and config.config.llm.api_key
+          local has_key = configured and utils.trim(configured) ~= ''
+          if not has_key then
+            for _, env_name in ipairs(env_keys[provider] or {}) do
+              local value = vim.env[env_name]
+              if value and utils.trim(value) ~= '' then
+                has_key = true
+                break
+              end
+            end
+          end
+
+          if has_key then
+            vim.health.ok('LLM API key is configured')
+          else
+            vim.health.error('LLM API key is missing', {
+              'Set `llm.api_key` in setup() or required env var for provider',
+            })
+          end
+        end
+      end
     else
       vim.health.warn('Plugin setup() has not been called', {
         "Call require('comment-translate').setup({}) in your config",

lua/comment-translate/translate/init.lua

@@ -2,6 +2,7 @@ local M = {}
 
 M.SERVICES = {
   google = 'google',
+  llm = 'llm',
 }
 
 ---@param service_name? string
@@ -13,6 +14,8 @@ local function get_service(service_name)
 
   if service_name == M.SERVICES.google then
     return require('comment-translate.translate.google'), nil
+  elseif service_name == M.SERVICES.llm then
+    return require('comment-translate.translate.llm'), nil
   else
     return nil, 'Unknown translate service: ' .. tostring(service_name)
   end
@@ -47,7 +50,7 @@ end
 
 ---@return string[]
 function M.get_available_services()
-  return { M.SERVICES.google }
+  return { M.SERVICES.google, M.SERVICES.llm }
 end
 
 return M