fix: autoscroll in case of early terminal focus (#111)

* fix: fix autoscroll in case of early terminal focus

* refactor: rename scroll functions

* feat: more proper autoscroll fix

* refactor: remove unused arg and debug log

* refactor: add arg type comments

* fix(scroll): minor tweaks

---------

Co-authored-by: Igor <[email protected]>

Author: Run1e

lua/dap-view/console/scroll.lua

@@ -6,39 +6,49 @@ local M = {}
 
 local api = vim.api
 
-local autoscroll = true
+---@type table<integer,boolean>
+local termbuf_is_autoscrolling = {}
 
 -- Inspired by nvim-dap-ui
 -- https://github.com/rcarriga/nvim-dap-ui/blob/73a26abf4941aa27da59820fd6b028ebcdbcf932/lua/dapui/elements/console.lua#L23-L46
 
 ---@param bufnr integer
-M.scroll = function(bufnr)
+M.setup_autoscroll = function(bufnr)
+    termbuf_is_autoscrolling[bufnr] = true
+
     api.nvim_create_autocmd({ "InsertEnter", "CursorMoved" }, {
         buffer = bufnr,
+        group = api.nvim_create_augroup("nvim-dap-view-scroll-" .. bufnr, {}),
         callback = function()
             local winnr = vim.tbl_contains(setup.config.winbar.sections, "console") and state.winnr or state.term_winnr
-            if util.is_win_valid(winnr) then
-                ---@cast winnr integer
-                local cursor = api.nvim_win_get_cursor(winnr)
-                autoscroll = cursor[1] == api.nvim_buf_line_count(bufnr)
+
+            if not util.is_win_valid(winnr) then
+                return
             end
+
+            ---@cast winnr integer
+            local cursor = api.nvim_win_get_cursor(winnr)
+
+            termbuf_is_autoscrolling[bufnr] = cursor[1] == api.nvim_buf_line_count(bufnr)
         end,
     })
 
     api.nvim_buf_attach(bufnr, false, {
         on_lines = function()
             local winnr = vim.tbl_contains(setup.config.winbar.sections, "console") and state.winnr or state.term_winnr
+
             if not util.is_win_valid(winnr) then
                 return
             end
+
             ---@cast winnr integer
-            if autoscroll and vim.fn.mode() == "n" then
+            if M.is_autoscrolling(bufnr) and vim.fn.mode() == "n" then
                 api.nvim_win_call(winnr, function()
                     if api.nvim_get_current_buf() == bufnr then
-                        -- vim.schedule ensures the cursor movement happens in the main event loop
-                        -- otherwise the call may happen too early
+                        -- Ensure the cursor movement happens in the main event loop
+                        -- Otherwise the call may happen too early
                         vim.schedule(function()
-                            api.nvim_win_set_cursor(winnr, { api.nvim_buf_line_count(bufnr), 0 })
+                            M.scroll_to_bottom(winnr, bufnr)
                         end)
                     end
                 end)
@@ -47,4 +57,29 @@ M.scroll = function(bufnr)
     })
 end
 
+---@param bufnr integer
+---@return boolean?
+M.is_autoscrolling = function(bufnr)
+    return termbuf_is_autoscrolling[bufnr]
+end
+
+---@param winnr integer
+---@param bufnr integer
+M.scroll_to_bottom = function(winnr, bufnr)
+    if util.is_win_valid(winnr) and util.is_buf_valid(bufnr) then
+        api.nvim_win_set_cursor(winnr, { api.nvim_buf_line_count(bufnr), 0 })
+
+        termbuf_is_autoscrolling[bufnr] = true
+    end
+end
+
+---@param bufnr integer
+M.cleanup_autoscroll = function(bufnr)
+    if termbuf_is_autoscrolling[bufnr] then
+        api.nvim_del_augroup_by_name("nvim-dap-view-scroll-" .. bufnr)
+    end
+
+    termbuf_is_autoscrolling[bufnr] = nil
+end
+
 return M

lua/dap-view/console/view.lua

@@ -6,6 +6,7 @@ local winbar = require("dap-view.options.winbar")
 local setup = require("dap-view.setup")
 local views = require("dap-view.views")
 local util = require("dap-view.util")
+local scroll = require("dap-view.console.scroll")
 
 local M = {}
 
@@ -58,11 +59,20 @@ M.show = function()
     ---`cleanup_view` ensures the buffer exists
     ---@cast term_buf integer
 
+    local is_autoscrolling = scroll.is_autoscrolling(term_buf)
+
     api.nvim_win_call(state.winnr, function()
         vim.wo[state.winnr][0].winfixbuf = false
         api.nvim_set_current_buf(term_buf)
         vim.wo[state.winnr][0].winfixbuf = true
     end)
+
+    -- When showing a session for the first time, assume the user wants autoscroll to just work™
+    -- That's necessary because when a terminal buffer is created, the number of lines is assigned to the number of
+    -- lines in the window. This may lead to autoscroll being set to false, since the user may not be "at the bottom".
+    if is_autoscrolling then
+        scroll.scroll_to_bottom(state.winnr, term_buf)
+    end
 end
 
 ---Hide the term win, does not affect the term buffer
@@ -139,7 +149,8 @@ M.setup_term_buf = function()
     end
 
     require("dap-view.console.keymaps").set_keymaps(term_bufnr)
-    require("dap-view.console.scroll").scroll(term_bufnr)
+
+    scroll.setup_autoscroll(term_bufnr)
 end
 
 M.switch_term_buf = function()

lua/dap-view/listeners.lua

@@ -11,6 +11,7 @@ local setup = require("dap-view.setup")
 local refresher = require("dap-view.refresher")
 local winbar = require("dap-view.options.winbar")
 local traversal = require("dap-view.tree.traversal")
+local scroll = require("dap-view.console.scroll")
 local adapter_ = require("dap-view.util.adapter")
 
 local SUBSCRIPTION_ID = "dap-view"
@@ -35,8 +36,20 @@ dap.listeners.on_session[SUBSCRIPTION_ID] = function(_, new)
         -- At this stage, the session is not fully initialized yet
         require("dap-view.exceptions").update_exception_breakpoints_filters()
 
-        if new.initialized and new.stopped_thread_id then
-            eval.reevaluate_all_expressions()
+        if new.initialized then
+            -- Handle autoscrolling when switching sessions
+            -- Straightforward way of taking into account "console" not being set
+            if util.is_buf_valid(new.term_buf) and scroll.is_autoscrolling(new.term_buf) then
+                local winnr = vim.tbl_contains(setup.config.winbar.sections, "console") and state.winnr
+                    or state.term_winnr
+                if util.is_win_valid(winnr) then
+                    ---@cast winnr integer
+                    scroll.scroll_to_bottom(winnr, new.term_buf)
+                end
+            end
+            if new.stopped_thread_id then
+                eval.reevaluate_all_expressions()
+            end
         end
     else
         state.current_session_id = nil
@@ -183,13 +196,17 @@ dap.listeners.after.event_terminated[SUBSCRIPTION_ID] = function(session)
     end
 
     winbar.redraw_controls()
+
+    scroll.cleanup_autoscroll(session.term_buf)
 end
 
 -- The debuggee was disconnected, which may happen outside of a "regular termination"
-dap.listeners.after.disconnect[SUBSCRIPTION_ID] = function()
+dap.listeners.after.disconnect[SUBSCRIPTION_ID] = function(session)
     refresher.refresh_session_based_views()
 
     winbar.redraw_controls()
+
+    scroll.cleanup_autoscroll(session.term_buf)
 end
 
 local winbar_redraw = { "event_exited", "event_stopped", "restart" }