feat(chat): Adding buffer watcher

lua/codecompanion/config.lua

@@ -261,67 +261,75 @@ Points to note:
           callback = "keymaps.pin_reference",
           description = "Pin Reference",
         },
+        watch = {
+          modes = {
+            n = "gw",
+          },
+          index = 10,
+          callback = "keymaps.toggle_watch",
+          description = "Watch Buffer",
+        },
         next_chat = {
           modes = {
             n = "}",
           },
-          index = 10,
+          index = 11,
           callback = "keymaps.next_chat",
           description = "Next Chat",
         },
         previous_chat = {
           modes = {
             n = "{",
           },
-          index = 11,
+          index = 12,
           callback = "keymaps.previous_chat",
           description = "Previous Chat",
         },
         next_header = {
           modes = {
             n = "]]",
           },
-          index = 12,
+          index = 13,
           callback = "keymaps.next_header",
           description = "Next Header",
         },
         previous_header = {
           modes = {
             n = "[[",
           },
-          index = 13,
+          index = 14,
           callback = "keymaps.previous_header",
           description = "Previous Header",
         },
         change_adapter = {
           modes = {
             n = "ga",
           },
-          index = 14,
+          index = 15,
           callback = "keymaps.change_adapter",
           description = "Change adapter",
         },
         fold_code = {
           modes = {
             n = "gf",
           },
-          index = 14,
+          index = 15,
           callback = "keymaps.fold_code",
           description = "Fold code",
         },
         debug = {
           modes = {
             n = "gd",
           },
-          index = 15,
+          index = 16,
           callback = "keymaps.debug",
           description = "View debug info",
         },
         system_prompt = {
           modes = {
             n = "gs",
           },
-          index = 16,
+          index = 17,
           callback = "keymaps.toggle_system_prompt",
           description = "Toggle the system prompt",
         },
@@ -817,6 +825,7 @@ This is the code, for context:
     chat = {
       icons = {
         pinned_buffer = " ",
+        watched_buffer = "👀 ",
       },
       window = {
         layout = "vertical", -- float|vertical|horizontal|buffer

lua/codecompanion/strategies/chat/init.lua

@@ -184,6 +184,7 @@ function Chat.new(args)
   self.parser = parser
 
   self.References = require("codecompanion.strategies.chat.references").new({ chat = self })
+  self.watcher = require("codecompanion.strategies.chat.watcher").new()
   self.tools = require("codecompanion.strategies.chat.tools").new({ bufnr = self.bufnr, messages = self.messages })
   self.variables = require("codecompanion.strategies.chat.variables").new()
 
@@ -577,6 +578,60 @@ function Chat:submit(opts)
   local bufnr = self.bufnr
 
   local message = ts_parse_messages(self, user_role, self.header_line)
+
+  for _, ref in ipairs(self.refs) do
+    if ref.bufnr and ref.opts and ref.opts.watched then
+      local changes = self.watcher:get_changes(ref.bufnr)
+      log:debug("Checking watched buffer %d, found %d changes", ref.bufnr, changes and #changes or 0)
+
+      if changes and #changes > 0 then
+        local changes_text = string.format(
+          "Changes detected in `%s` (buffer %d):\n",
+          vim.fn.fnamemodify(api.nvim_buf_get_name(ref.bufnr), ":t"),
+          ref.bufnr
+        )
+
+        for _, change in ipairs(changes) do
+          if change.type == "delete" then
+            changes_text = changes_text
+              .. string.format(
+                "Lines %d-%d were deleted:\n```%s\n%s\n```\n",
+                change.start,
+                change.end_line,
+                vim.bo[ref.bufnr].filetype,
+                table.concat(change.lines, "\n")
+              )
+          elseif change.type == "modify" then
+            changes_text = changes_text
+              .. string.format(
+                "Lines %d-%d were modified from:\n```%s\n%s\n```\nto:\n```%s\n%s\n```\n",
+                change.start,
+                change.end_line,
+                vim.bo[ref.bufnr].filetype,
+                table.concat(change.old_lines, "\n"),
+                vim.bo[ref.bufnr].filetype,
+                table.concat(change.new_lines, "\n")
+              )
+          else -- type == "add"
+            changes_text = changes_text
+              .. string.format(
+                "Lines %d-%d were added:\n```%s\n%s\n```\n",
+                change.start,
+                change.end_line,
+                vim.bo[ref.bufnr].filetype,
+                table.concat(change.lines, "\n")
+              )
+          end
+        end
+
+        self:add_message({
+          role = config.constants.USER_ROLE,
+          content = changes_text,
+        }, { visible = true })
+      end
+    end
+  end
+
   if not self:has_user_messages(message) or message.content == "" then
     return log:warn("No messages to submit")
   end

lua/codecompanion/strategies/chat/keymaps.lua

@@ -354,6 +354,59 @@ M.pin_reference = {
   end,
 }
 
+M.toggle_watch = {
+  desc = "Toggle Watch Buffer",
+  callback = function(chat)
+    local current_line = vim.api.nvim_win_get_cursor(0)[1]
+    local line = vim.api.nvim_buf_get_lines(chat.bufnr, current_line - 1, current_line, true)[1]
+
+    if not vim.startswith(line, "> - ") then
+      return
+    end
+
+    local icons = config.display.chat.icons
+    local id = line:gsub("^> %- ", "")
+    if not chat.References:can_be_watched(id) then
+      return util.notify("This reference type cannot be watched", vim.log.levels.WARN)
+    end
+
+    -- Find the reference and toggle watch state
+    for _, ref in ipairs(chat.refs) do
+      local clean_id = id:gsub(icons.pinned_buffer, ""):gsub(icons.watched_buffer, "")
+      if ref.id == clean_id then
+        if not ref.opts then
+          ref.opts = {}
+        end
+        ref.opts.watched = not ref.opts.watched
+
+        -- Update the UI for just this line
+        local new_line
+        if ref.opts.watched then
+          -- Check if buffer is still valid before watching
+          if vim.api.nvim_buf_is_valid(ref.bufnr) and vim.api.nvim_buf_is_loaded(ref.bufnr) then
+            chat.watcher:watch(ref.bufnr)
+            new_line = string.format("> - %s%s", icons.watched_buffer, clean_id)
+            util.notify("Now watching buffer " .. ref.id)
+          else
+            -- Buffer is invalid, can't watch it
+            ref.opts.watched = false
+            new_line = string.format("> - %s", clean_id)
+            util.notify("Cannot watch invalid or unloaded buffer " .. ref.id, vim.log.levels.WARN)
+          end
+        else
+          chat.watcher:unwatch(ref.bufnr)
+          new_line = string.format("> - %s", clean_id)
+          util.notify("Stopped watching buffer " .. ref.id)
+        end
+
+        -- Update only the current line
+        vim.api.nvim_buf_set_lines(chat.bufnr, current_line - 1, current_line, true, { new_line })
+        break
+      end
+    end
+  end,
+}
+
 ---@param chat CodeCompanion.Chat
 ---@param direction number
 local function move_buffer(chat, direction)

lua/codecompanion/strategies/chat/references.lua

@@ -8,12 +8,17 @@ local config = require("codecompanion.config")
 local api = vim.api
 local user_role = config.strategies.chat.roles.user
 local pinned_icon = config.display.chat.icons.pinned_buffer
+local watched_icon = config.display.chat.icons.watched_buffer
 
 local allowed_pins = {
   "<buf>",
   "<file>",
 }
 
+local allowed_watches = {
+  "<buf>",
+}
+
 ---Parse the chat buffer to find where to add the references
 ---@param chat CodeCompanion.Chat
 ---@return table|nil
@@ -106,11 +111,16 @@ function References:add(ref)
 
   if ref then
     if not ref.opts then
-      ref.opts = {
-        pinned = false,
-      }
+      ref.opts = {}
     end
+    -- Ensure both properties exist with defaults
+    ref.opts.pinned = ref.opts.pinned or false
+    ref.opts.watched = ref.opts.watched or false
     table.insert(self.Chat.refs, ref)
+    -- If it's a buffer reference and it's being watched, start watching
+    if ref.bufnr and ref.opts.watched then
+      self.Chat.watcher:watch(ref.bufnr)
+    end
   end
 
   local parsed_buffer = ts_parse_buffer(self.Chat)
@@ -176,6 +186,8 @@ function References:render()
     end
     if ref.opts and ref.opts.pinned then
       table.insert(lines, string.format("> - %s%s", pinned_icon, ref.id))
+    elseif ref.opts and ref.opts.watched then
+      table.insert(lines, string.format("> - %s%s", watched_icon, ref.id))
     else
       table.insert(lines, string.format("> - %s", ref.id))
     end
@@ -206,6 +218,18 @@ function References:can_be_pinned(ref)
   return false
 end
 
+---Determine if a reference can be watched
+---@param ref string
+---@return boolean
+function References:can_be_watched(ref)
+  for _, watch in ipairs(allowed_watches) do
+    if ref:find(watch) then
+      return true
+    end
+  end
+  return false
+end
+
 ---Get the references from the chat buffer
 ---@return table
 function References:get_from_chat()
@@ -225,7 +249,8 @@ function References:get_from_chat()
       role = role:gsub("## ", "")
     elseif role == user_role and query.captures[id] == "ref" then
       local ref = vim.treesitter.get_node_text(node, chat.bufnr)
-      ref = ref:gsub("^> %- ", ""):gsub(pinned_icon, "")
+      -- Clean both pinned and watched icons
+      ref = ref:gsub("^> %- ", ""):gsub(pinned_icon, ""):gsub(watched_icon, "")
       table.insert(refs, vim.trim(ref))
     end
   end