From 2ac311a2666edb447db5139b326777c44adc1e2a Mon Sep 17 00:00:00 2001
From: JINNOUCHI Yasushi <me@delphinus.dev>
Date: Sat, 12 Aug 2023 15:30:25 +0900
Subject: [PATCH] fix: reflow results to show valid ones (#123)

* fix: clear non-matched results in results buffer

* fix: show high-scored results in the first view

This is for sorting_strategy = 'descending'
---
 lua/frecency/async_finder.lua            | 36 ++++++++++++++++++++++--
 lua/frecency/finder.lua                  |  5 ++--
 lua/frecency/picker.lua                  | 13 ++++++---
 lua/frecency/state.lua                   | 21 ++++++++++++++
 lua/frecency/tests/async_finder_spec.lua |  3 +-
 lua/frecency/types.lua                   | 17 +++++++++++
 6 files changed, 86 insertions(+), 9 deletions(-)
 create mode 100644 lua/frecency/state.lua

diff --git a/lua/frecency/async_finder.lua b/lua/frecency/async_finder.lua
index 12a4654..7aae334 100644
--- a/lua/frecency/async_finder.lua
+++ b/lua/frecency/async_finder.lua
@@ -3,17 +3,20 @@ local async = require "plenary.async" --[[@as PlenaryAsync]]
 ---@class FrecencyAsyncFinder
 ---@field closed boolean
 ---@field entries FrecencyEntry[]
+---@field reflowed boolean
 ---@field rx PlenaryAsyncControlChannelRx
+---@field state FrecencyState
 ---@overload fun(_: string, process_result: (fun(entry: FrecencyEntry): nil), process_complete: fun(): nil): nil
 local AsyncFinder = {}
 
 ---@param fs FrecencyFS
+---@param state FrecencyState
 ---@param path string
 ---@param entry_maker fun(file: FrecencyFile): FrecencyEntry
 ---@param initial_results FrecencyFile[]
 ---@return FrecencyAsyncFinder
-AsyncFinder.new = function(fs, path, entry_maker, initial_results)
-  local self = setmetatable({ closed = false, entries = {} }, {
+AsyncFinder.new = function(state, fs, path, entry_maker, initial_results)
+  local self = setmetatable({ closed = false, entries = {}, reflowed = false, state = state }, {
     __index = AsyncFinder,
     ---@param self FrecencyAsyncFinder
     __call = function(self, ...)
@@ -47,6 +50,7 @@ AsyncFinder.new = function(fs, path, entry_maker, initial_results)
           table.insert(self.entries, entry)
           tx.send(entry)
           if count % 1000 == 0 then
+            self:reflow_results()
             -- NOTE: This is needed not to lock text input.
             async.util.sleep(50)
           end
@@ -88,4 +92,32 @@ function AsyncFinder:close()
   self.closed = true
 end
 
+---@return nil
+function AsyncFinder:reflow_results()
+  local picker = self.state:get()
+  if not picker then
+    return
+  end
+  local bufnr = picker.results_bufnr
+  local win = picker.results_win
+  if not bufnr or not win then
+    return
+  end
+  picker:clear_extra_rows(bufnr)
+  if picker.sorting_strategy == "descending" then
+    local manager = picker.manager
+    if not manager then
+      return
+    end
+    local worst_line = picker:get_row(manager:num_results())
+    ---@type WinInfo
+    local wininfo = vim.fn.getwininfo(win)[1]
+    local bottom = vim.api.nvim_buf_line_count(bufnr)
+    if not self.reflowed or worst_line > wininfo.botline then
+      self.reflowed = true
+      vim.api.nvim_win_set_cursor(win, { bottom, 0 })
+    end
+  end
+end
+
 return AsyncFinder
diff --git a/lua/frecency/finder.lua b/lua/frecency/finder.lua
index c824f2d..014ee88 100644
--- a/lua/frecency/finder.lua
+++ b/lua/frecency/finder.lua
@@ -27,11 +27,12 @@ end
 ---@field workspace string?
 ---@field workspace_tag string?
 
+---@param state FrecencyState
 ---@param filepath_formatter FrecencyFilepathFormatter
 ---@param initial_results table
 ---@param opts FrecencyFinderOptions
 ---@return table
-function Finder:start(filepath_formatter, initial_results, opts)
+function Finder:start(state, filepath_formatter, initial_results, opts)
   local entry_maker = self.entry_maker:create(filepath_formatter, opts.workspace, opts.workspace_tag)
   if not opts.need_scandir then
     return finders.new_table {
@@ -40,7 +41,7 @@ function Finder:start(filepath_formatter, initial_results, opts)
     }
   end
   log.debug { finder = opts }
-  return AsyncFinder.new(self.fs, opts.workspace, entry_maker, initial_results)
+  return AsyncFinder.new(state, self.fs, opts.workspace, entry_maker, initial_results)
 end
 
 return Finder
diff --git a/lua/frecency/picker.lua b/lua/frecency/picker.lua
index 2c13b83..0c55cfe 100644
--- a/lua/frecency/picker.lua
+++ b/lua/frecency/picker.lua
@@ -1,3 +1,4 @@
+local State = require "frecency.state"
 local log = require "plenary.log"
 local Path = require "plenary.path" --[[@as PlenaryPath]]
 local actions = require "telescope.actions"
@@ -83,8 +84,10 @@ function Picker:start(opts)
     self.results = self:fetch_results(self.workspace)
   end
 
+  local state = State.new()
+
   local filepath_formatter = self:filepath_formatter(opts)
-  local finder = self.finder:start(filepath_formatter, self.results, {
+  local finder = self.finder:start(state, filepath_formatter, self.results, {
     need_scandir = self.workspace and self.config.show_unindexed and true or false,
     workspace = self.workspace,
     workspace_tag = self.config.initial_workspace_tag,
@@ -95,11 +98,12 @@ function Picker:start(opts)
     finder = finder,
     previewer = config_values.file_previewer(opts),
     sorter = sorters.get_substr_matcher(),
-    on_input_filter_cb = self:on_input_filter_cb(opts),
+    on_input_filter_cb = self:on_input_filter_cb(state, opts),
     attach_mappings = function(prompt_bufnr)
       return self:attach_mappings(prompt_bufnr)
     end,
   })
+  state:set(picker)
   picker:find()
   self:set_prompt_options(picker.prompt_bufnr)
 end
@@ -227,9 +231,10 @@ function Picker:get_lsp_workspace()
 end
 
 ---@private
+---@param state FrecencyState
 ---@param picker_opts table
 ---@return fun(prompt: string): table
-function Picker:on_input_filter_cb(picker_opts)
+function Picker:on_input_filter_cb(state, picker_opts)
   local filepath_formatter = self:filepath_formatter(picker_opts)
   return function(prompt)
     local workspace
@@ -243,7 +248,7 @@ function Picker:on_input_filter_cb(picker_opts)
     if self.workspace ~= workspace then
       self.workspace = workspace
       self.results = self:fetch_results(workspace)
-      opts.updated_finder = self.finder:start(filepath_formatter, self.results, {
+      opts.updated_finder = self.finder:start(state, filepath_formatter, self.results, {
         initial_results = self.results,
         need_scandir = self.workspace and self.config.show_unindexed and true or false,
         workspace = self.workspace,
diff --git a/lua/frecency/state.lua b/lua/frecency/state.lua
new file mode 100644
index 0000000..15b204c
--- /dev/null
+++ b/lua/frecency/state.lua
@@ -0,0 +1,21 @@
+---@class FrecencyState
+---@field picker TelescopePicker?
+local State = {}
+
+---@return FrecencyState
+State.new = function()
+  return setmetatable({}, { __index = State, __meta = "kv" })
+end
+
+---@param picker TelescopePicker?
+---@return nil
+function State:set(picker)
+  self.picker = picker
+end
+
+---@return TelescopePicker?
+function State:get()
+  return self.picker
+end
+
+return State
diff --git a/lua/frecency/tests/async_finder_spec.lua b/lua/frecency/tests/async_finder_spec.lua
index 01ac29d..f3158e9 100644
--- a/lua/frecency/tests/async_finder_spec.lua
+++ b/lua/frecency/tests/async_finder_spec.lua
@@ -1,5 +1,6 @@
 ---@diagnostic disable: invisible
 local AsyncFinder = require "frecency.async_finder"
+local State = require "frecency.state"
 local FS = require "frecency.fs"
 local EntryMaker = require "frecency.entry_maker"
 local WebDevicons = require "frecency.web_devicons"
@@ -22,7 +23,7 @@ local function with_files(files, initial_results, callback)
   local initials = vim.tbl_map(function(v)
     return { path = (dir / v):absolute() }
   end, initial_results)
-  local async_finder = AsyncFinder.new(fs, dir:absolute(), entry_maker, initials)
+  local async_finder = AsyncFinder.new(State.new(), fs, dir:absolute(), entry_maker, initials)
   callback(async_finder, dir)
   close()
 end
diff --git a/lua/frecency/types.lua b/lua/frecency/types.lua
index 232ccf5..7fb44fa 100644
--- a/lua/frecency/types.lua
+++ b/lua/frecency/types.lua
@@ -117,3 +117,20 @@ function PlenaryAsyncUtil.sleep(ms) end
 ---@field path_tail fun(path: string): string
 ---@field transform_path fun(opts: table, path: string): string
 ---@field buf_is_loaded fun(filename: string): boolean
+
+---@class TelescopePicker
+---@field clear_extra_rows fun(self: TelescopePicker, results_bufnr: integer): nil
+---@field get_row fun(self: TelescopePicker, index: integer): integer
+---@field manager TelescopeEntryManager|false
+---@field results_bufnr integer?
+---@field results_win integer?
+---@field sorting_strategy 'ascending'|'descending'
+
+---@class TelescopeEntryManager
+---@field num_results fun(): integer
+
+-- NOTE: types for default functions
+
+---@class WinInfo
+---@field topline integer
+---@field botline integer