From dea927d0eb22255632dd82d2efff1a68d621c871 Mon Sep 17 00:00:00 2001
From: TJ DeVries <devries.timothyj@gmail.com>
Date: Fri, 8 Oct 2021 07:56:01 -0700
Subject: [PATCH] feat: Add scrolling through results (#1232)

* some scrollin

* [WIP]: Fri 10 Sep 2021 02:24:20 PM EDT

* ok, I think scrolling works

* change to 1000 for now, dont need to scroll that far :)
---
 ftplugin/TelescopeResults.lua              |   2 +
 lua/telescope/entry_manager.lua            |  21 ---
 lua/telescope/finders/async_job_finder.lua |   1 +
 lua/telescope/log.lua                      |   4 +-
 lua/telescope/pickers.lua                  | 189 +++++++++++----------
 5 files changed, 101 insertions(+), 116 deletions(-)
 create mode 100644 ftplugin/TelescopeResults.lua

diff --git a/ftplugin/TelescopeResults.lua b/ftplugin/TelescopeResults.lua
new file mode 100644
index 0000000..1b93571
--- /dev/null
+++ b/ftplugin/TelescopeResults.lua
@@ -0,0 +1,2 @@
+-- Don't have scrolloff, it makes things weird.
+vim.opt.scrolloff = 0
diff --git a/lua/telescope/entry_manager.lua b/lua/telescope/entry_manager.lua
index 5055171..1e94c80 100644
--- a/lua/telescope/entry_manager.lua
+++ b/lua/telescope/entry_manager.lua
@@ -2,27 +2,6 @@ local log = require "telescope.log"
 
 local LinkedList = require "telescope.algos.linked_list"
 
---[[
-
-OK, new idea.
-We can do linked list here.
-To convert at the end to quickfix, just run the list.
-...
-
-start node
-end node
-
-if past loop of must have scores,
-  then we can just add to end node and shift end node to current node.
-  etc.
-
-
-  always inserts a row, because we clear everything before?
-
-  can also optimize by keeping worst acceptable score around.
-
---]]
-
 local EntryManager = {}
 EntryManager.__index = EntryManager
 
diff --git a/lua/telescope/finders/async_job_finder.lua b/lua/telescope/finders/async_job_finder.lua
index 17799e8..5a96d1d 100644
--- a/lua/telescope/finders/async_job_finder.lua
+++ b/lua/telescope/finders/async_job_finder.lua
@@ -7,6 +7,7 @@ local log = require "telescope.log"
 return function(opts)
   log.trace("Creating async_job:", opts)
   local entry_maker = opts.entry_maker or make_entry.gen_from_string()
+
   local fn_command = function(prompt)
     local command_list = opts.command_generator(prompt)
     if command_list == nil then
diff --git a/lua/telescope/log.lua b/lua/telescope/log.lua
index 0d2e0eb..c74378f 100644
--- a/lua/telescope/log.lua
+++ b/lua/telescope/log.lua
@@ -1,6 +1,4 @@
-local user = vim.loop.os_getenv "USER"
-
 return require("plenary.log").new {
   plugin = "telescope",
-  level = ((user == "tj" or user == "tjdevries") and "debug") or "warn",
+  level = "info",
 }
diff --git a/lua/telescope/pickers.lua b/lua/telescope/pickers.lua
index 09a062f..6b9db5e 100644
--- a/lua/telescope/pickers.lua
+++ b/lua/telescope/pickers.lua
@@ -213,28 +213,17 @@ function Picker:clear_extra_rows(results_bufnr)
   end
 
   if not ok then
-    log.debug(msg)
+    log.debug("Failed to set lines:", msg)
   end
 
   log.trace("Clearing:", worst_line)
 end
 
-function Picker:highlight_displayed_rows(results_bufnr, prompt)
-  if not self.sorter or not self.sorter.highlighter then
+function Picker:highlight_one_row(results_bufnr, prompt, display, row)
+  if not self.sorter.highlighter then
     return
   end
 
-  vim.api.nvim_buf_clear_namespace(results_bufnr, ns_telescope_matching, 0, -1)
-
-  local displayed_rows = vim.api.nvim_buf_get_lines(results_bufnr, 0, -1, false)
-  for row_index = 1, math.min(#displayed_rows, self.max_results) do
-    local display = displayed_rows[row_index]
-
-    self:highlight_one_row(results_bufnr, prompt, display, row_index - 1)
-  end
-end
-
-function Picker:highlight_one_row(results_bufnr, prompt, display, row)
   local highlights = self.sorter:highlighter(prompt, display)
 
   if highlights then
@@ -352,22 +341,19 @@ function Picker:find()
   self.prompt_prefix = prompt_prefix
   self:_reset_prefix_color()
 
-  -- First thing we want to do is set all the lines to blank.
-  self.max_results = popup_opts.results.height
+  -- TODO: This could be configurable in the future, but I don't know why you would
+  -- want to scroll through more than 10,000 items.
+  --
+  -- This just lets us stop doing stuff after tons of  things.
+  self.max_results = 1000
 
-  -- TODO(scrolling): This may be a hack when we get a little further into implementing scrolling.
   vim.api.nvim_buf_set_lines(results_bufnr, 0, self.max_results, false, utils.repeated_table(self.max_results, ""))
 
-  -- TODO(status): I would love to get the status text not moving back and forth. Perhaps it is just a problem with
-  -- virtual text & prompt buffers or something though. I can't figure out why it would redraw the way it does.
-  --
-  -- A "hacked" version of this would be to calculate where the area I want the status to go and put a new window there.
-  -- With this method, I do not need to worry about padding or antying, just make it take up X characters or something.
   local status_updater = self:get_status_updater(prompt_win, prompt_bufnr)
   local debounced_status = debounce.throttle_leading(status_updater, 50)
 
   local tx, rx = channel.mpsc()
-  self.__on_lines = tx.send
+  self._on_lines = tx.send
 
   local find_id = self:_next_find_id()
 
@@ -412,25 +398,14 @@ function Picker:find()
 
       local start_time = vim.loop.hrtime()
 
-      local prompt = self:_get_prompt()
-      local on_input_result = self._on_input_filter_cb(prompt) or {}
-
-      local new_prompt = on_input_result.prompt
-      if new_prompt then
-        prompt = new_prompt
-      end
-
-      local new_finder = on_input_result.updated_finder
-      if new_finder then
-        self.finder:close()
-        self.finder = new_finder
-      end
+      local prompt = self:_get_next_filtered_prompt()
 
       -- TODO: Entry manager should have a "bulk" setter. This can prevent a lot of redraws from display
       if self.cache_picker == false or not (self.cache_picker.is_cached == true) then
         self.sorter:_start(prompt)
         self.manager = EntryManager:new(self.max_results, self.entry_adder, self.stats)
 
+        vim.api.nvim_buf_clear_namespace(results_bufnr, ns_telescope_matching, 0, -1)
         local process_result = self:get_result_processor(find_id, prompt, debounced_status)
         local process_complete = self:get_result_completor(self.results_bufnr, find_id, prompt, status_updater)
 
@@ -447,26 +422,8 @@ function Picker:find()
           async.util.sleep(self.debounce - diff_time)
         end
       else
-        -- resume previous picker
-        local index = 1
-        for entry in self.manager:iter() do
-          self:entry_adder(index, entry, _, true)
-          index = index + 1
-        end
-        self.cache_picker.is_cached = false
-        -- if text changed, required to set anew to restart finder; otherwise hl and selection
-        if self.cache_picker.cached_prompt ~= self.default_text then
-          self:reset_prompt()
-          self:set_prompt(self.default_text)
-        else
-          -- scheduling required to apply highlighting and selection appropriately
-          await_schedule(function()
-            self:highlight_displayed_rows(self.results_bufnr, self.cache_picker.cached_prompt)
-            if self.cache_picker.selection_row ~= nil then
-              self:set_selection(self.cache_picker.selection_row)
-            end
-          end)
-        end
+        -- TODO(scroll): This can only happen once, I don't like where it is.
+        self:_resume_picker()
       end
     end
   end)
@@ -476,10 +433,10 @@ function Picker:find()
     on_lines = function(...)
       find_id = self:_next_find_id()
 
-      self._result_completed = false
       status_updater { completed = false }
-      tx.send(...)
+      self._on_lines(...)
     end,
+
     on_detach = function()
       self:_detach()
     end,
@@ -753,7 +710,7 @@ function Picker:refresh(finder, opts)
     self._multi = MultiSelect:new()
   end
 
-  self.__on_lines(nil, nil, nil, 0, 1)
+  self._on_lines(nil, nil, nil, 0, 1)
 end
 
 function Picker:set_selection(row)
@@ -856,6 +813,8 @@ function Picker:set_selection(row)
   self._selection_row = row
 
   self:refresh_previewer()
+
+  vim.api.nvim_win_set_cursor(self.results_win, { row + 1, 0 })
 end
 
 function Picker:refresh_previewer()
@@ -918,43 +877,41 @@ function Picker:entry_adder(index, entry, _, insert)
 
   self:_increment "displayed"
 
-  -- TODO: Don't need to schedule this if we schedule the adder.
   local offset = insert and 0 or 1
-  vim.schedule(function()
-    if not vim.api.nvim_buf_is_valid(self.results_bufnr) then
-      log.debug "ON_ENTRY: Invalid buffer"
-      return
-    end
+  if not vim.api.nvim_buf_is_valid(self.results_bufnr) then
+    log.debug "ON_ENTRY: Invalid buffer"
+    return
+  end
 
-    -- TODO: Does this every get called?
-    -- local line_count = vim.api.nvim_win_get_height(self.results_win)
-    local line_count = vim.api.nvim_buf_line_count(self.results_bufnr)
-    if row > line_count then
-      return
-    end
+  -- TODO: Does this every get called?
+  -- local line_count = vim.api.nvim_win_get_height(self.results_win)
+  local line_count = vim.api.nvim_buf_line_count(self.results_bufnr)
+  if row > line_count then
+    return
+  end
 
-    if insert then
-      if self.sorting_strategy == "descending" then
-        vim.api.nvim_buf_set_lines(self.results_bufnr, 0, 1, false, {})
-      end
+  if insert then
+    if self.sorting_strategy == "descending" then
+      vim.api.nvim_buf_set_lines(self.results_bufnr, 0, 1, false, {})
     end
+  end
 
-    local set_ok, msg = pcall(vim.api.nvim_buf_set_lines, self.results_bufnr, row, row + offset, false, { display })
-    if set_ok and display_highlights then
-      self.highlighter:hi_display(row, prefix, display_highlights)
-    end
+  local set_ok, msg = pcall(vim.api.nvim_buf_set_lines, self.results_bufnr, row, row + offset, false, { display })
+  if set_ok and display_highlights then
+    self.highlighter:hi_display(row, prefix, display_highlights)
+    self:highlight_one_row(self.results_bufnr, self:_get_prompt(), display, row)
+  end
 
-    if not set_ok then
-      log.debug("Failed to set lines...", msg)
-    end
+  if not set_ok then
+    log.debug("Failed to set lines...", msg)
+  end
 
-    -- This pretty much only fails when people leave newlines in their results.
-    --  So we'll clean it up for them if it fails.
-    if not set_ok and display:find "\n" then
-      display = display:gsub("\n", " | ")
-      vim.api.nvim_buf_set_lines(self.results_bufnr, row, row + 1, false, { display })
-    end
-  end)
+  -- This pretty much only fails when people leave newlines in their results.
+  --  So we'll clean it up for them if it fails.
+  if not set_ok and display:find "\n" then
+    display = display:gsub("\n", " | ")
+    vim.api.nvim_buf_set_lines(self.results_bufnr, row, row + 1, false, { display })
+  end
 end
 
 function Picker:_reset_track()
@@ -1025,6 +982,8 @@ function Picker:get_status_updater(prompt_win, prompt_bufnr)
 end
 
 function Picker:get_result_processor(find_id, prompt, status_updater)
+  local count = 0
+
   local cb_add = function(score, entry)
     self.manager:add_entry(self, score, entry)
     status_updater { completed = false }
@@ -1045,6 +1004,8 @@ function Picker:get_result_processor(find_id, prompt, status_updater)
       return
     end
 
+    count = count + 1
+
     -- TODO: Probably should asyncify this / cache this / do something because this probably takes
     -- a ton of time on large results.
     log.trace("Processing result... ", entry)
@@ -1060,6 +1021,13 @@ function Picker:get_result_processor(find_id, prompt, status_updater)
     end
 
     self.sorter:score(prompt, entry, cb_add, cb_filter)
+
+    -- Only on the first addition do we want to set the selection.
+    -- This allows us to handle moving the cursor to the bottom or top of the window
+    -- depending on the strategy.
+    if count == 1 then
+      self:_do_selection(prompt)
+    end
   end
 end
 
@@ -1075,12 +1043,9 @@ function Picker:get_result_completor(results_bufnr, find_id, prompt, status_upda
     status_updater { completed = true }
 
     self:clear_extra_rows(results_bufnr)
-    self:highlight_displayed_rows(results_bufnr, prompt)
     self.sorter:_finish(prompt)
 
     self:_on_complete()
-
-    self._result_completed = true
   end)
 end
 
@@ -1226,6 +1191,46 @@ function Picker:_detach()
   self.closed = true
 end
 
+function Picker:_get_next_filtered_prompt()
+  local prompt = self:_get_prompt()
+  local on_input_result = self._on_input_filter_cb(prompt) or {}
+
+  local new_prompt = on_input_result.prompt
+  if new_prompt then
+    prompt = new_prompt
+  end
+
+  local new_finder = on_input_result.updated_finder
+  if new_finder then
+    self.finder:close()
+    self.finder = new_finder
+  end
+
+  return prompt
+end
+
+function Picker:_resume_picker()
+  -- resume previous picker
+  local index = 1
+  for entry in self.manager:iter() do
+    self:entry_adder(index, entry, _, true)
+    index = index + 1
+  end
+  self.cache_picker.is_cached = false
+  -- if text changed, required to set anew to restart finder; otherwise hl and selection
+  if self.cache_picker.cached_prompt ~= self.default_text then
+    self:reset_prompt()
+    self:set_prompt(self.default_text)
+  else
+    -- scheduling required to apply highlighting and selection appropriately
+    await_schedule(function()
+      if self.cache_picker.selection_row ~= nil then
+        self:set_selection(self.cache_picker.selection_row)
+      end
+    end)
+  end
+end
+
 pickers._Picker = Picker
 
 return pickers