feat: Do a bit better sorting for command history

To be honest, I'm not 100% sure this is fantastic, but it's definitely a
step in the right direction for command history.

Closes: #150

6 files changed, 59 insertions, 29 deletions

diff --git a/lua/telescope/builtin.lua b/lua/telescope/builtin.lua
index 6b51036..c483a7b 100644
--- a/lua/telescope/builtin.lua
+++ b/lua/telescope/builtin.lua
@@ -79,7 +79,6 @@ builtin.commands = function()
       entry_maker = function(line)
         return {
           valid = line ~= "",
-          entry_type = make_entry.types.GENERIC,
           value = line,
           ordinal = line.name,
           display = line.name
@@ -233,7 +232,6 @@ builtin.lsp_code_actions = function(opts)
       entry_maker = function(line)
         return {
           valid = line ~= nil,
-          entry_type = make_entry.types.GENERIC,
           value = line,
           ordinal = line.idx .. line.title,
           display = line.idx .. ': ' .. line.title
@@ -382,7 +380,7 @@ builtin.command_history = function(opts)
   local history_list = vim.split(history_string, "\n")
 
   local results = {}
-  for i = 3, #history_list do
+  for i = #history_list, 3, -1 do
     local item = history_list[i]
     local _, finish = string.find(item, "%d+ +")
     table.insert(results, string.sub(item, finish + 1))
@@ -391,7 +389,7 @@ builtin.command_history = function(opts)
   pickers.new(opts, {
     prompt = 'Command History',
     finder = finders.new_table(results),
-    sorter = sorters.get_generic_fuzzy_sorter(),
+    sorter = sorters.fuzzy_with_index_bias(),
 
     attach_mappings = function(_, map)
       map('i', '<CR>', actions.set_command_line)
@@ -399,12 +397,8 @@ builtin.command_history = function(opts)
       -- TODO: Find a way to insert the text... it seems hard.
       -- map('i', '<C-i>', actions.insert_value, { expr = true })
 
-      -- Please add the default mappings for me for the rest of the keys.
       return true
     end,
-
-    -- TODO: Adapt `help` to this.
-    -- previewer = previewers.cat,
   }):find()
 end
 
diff --git a/lua/telescope/entry_manager.lua b/lua/telescope/entry_manager.lua
index 532cca2..d53586e 100644
--- a/lua/telescope/entry_manager.lua
+++ b/lua/telescope/entry_manager.lua
@@ -113,7 +113,7 @@ function EntryManager:insert(picker, index, entry)
     self.info.inserted = self.info.inserted + 1 
     next_entry = self.entry_state[index]
 
-    self.set_entry(picker, index, entry.entry)
+    self.set_entry(picker, index, entry.entry, entry.score)
     self.entry_state[index] = entry
 
     last_score = entry.score
diff --git a/lua/telescope/finders.lua b/lua/telescope/finders.lua
index a9222e7..a3ca097 100644
--- a/lua/telescope/finders.lua
+++ b/lua/telescope/finders.lua
@@ -33,7 +33,7 @@ local JobFinder = _callable_obj()
 function JobFinder:new(opts)
   opts = opts or {}
 
-  assert(not opts.results, "`results` should be used with finder.new_table")
+> assert(not opts.results, "`results` should be used with finder.new_table")
   assert(not opts.static, "`static` should be used with finder.new_oneshot_job")
 
   local obj = setmetatable({
@@ -238,8 +238,11 @@ function StaticFinder:new(opts)
   assert(type(input_results) == 'table', "self.results must be a table")
 
   local results = {}
-  for _, v in ipairs(input_results) do
-    table.insert(results, entry_maker(v))
+  for k, v in ipairs(input_results) do
+    local entry = entry_maker(v)
+    entry.index = k
+
+    table.insert(results, entry)
   end
 
   return setmetatable({ results = results }, self)
diff --git a/lua/telescope/pickers.lua b/lua/telescope/pickers.lua
index f28ae6a..3dc0caa 100644
--- a/lua/telescope/pickers.lua
+++ b/lua/telescope/pickers.lua
@@ -741,7 +741,7 @@ function Picker:set_selection(row)
 end
 
 
-function Picker:entry_adder(index, entry)
+function Picker:entry_adder(index, entry, score)
   local row = self:get_row(index)
 
   -- If it's less than 0, then we don't need to show it at all.
@@ -764,7 +764,11 @@ function Picker:entry_adder(index, entry)
   -- This is the two spaces to manage the '> ' stuff.
   -- Maybe someday we can use extmarks or floaty text or something to draw this and not insert here.
   -- until then, insert two spaces
-  display = '  ' .. display
+  if TELESCOPE_DEBUG then
+    display = '  ' .. score .. display
+  else
+    display = '  ' .. display
+  end
 
   self:_increment("displayed")
 
diff --git a/lua/telescope/pickers/layout_strategies.lua b/lua/telescope/pickers/layout_strategies.lua
index b43466c..390c748 100644
--- a/lua/telescope/pickers/layout_strategies.lua
+++ b/lua/telescope/pickers/layout_strategies.lua
@@ -75,17 +75,22 @@ layout_strategies.horizontal = function(self, max_columns, max_lines)
   end)(self, max_columns, max_lines)
   local picker_height = max_lines - 2 * height_padding
 
-  preview.width = resolve.resolve_width(layout_config.preview_width or function(_, cols)
-    if not self.previewer or cols < self.preview_cutoff then
-      return 0
-    elseif cols < 150 then
-      return math.floor(cols * 0.4)
-    elseif cols < 200 then
-      return 80
-    else
-      return 120
-    end
-  end)(self, picker_width, max_lines)
+  if self.previewer then
+    preview.width = resolve.resolve_width(layout_config.preview_width or function(_, cols)
+      if not self.previewer or cols < self.preview_cutoff then
+        return 0
+      elseif cols < 150 then
+        return math.floor(cols * 0.4)
+      elseif cols < 200 then
+        return 80
+      else
+        return 120
+      end
+    end)(self, picker_width, max_lines)
+  else
+    preview.width = 0
+  end
+
   results.width = picker_width - preview.width
   prompt.width = picker_width - preview.width
 
@@ -114,7 +119,7 @@ layout_strategies.horizontal = function(self, max_columns, max_lines)
   end
 
   return {
-    preview = preview.width > 0 and preview,
+    preview = self.previewer and preview.width > 0 and preview,
     results = results,
     prompt = prompt
 }
@@ -174,7 +179,7 @@ layout_strategies.center = function(self, columns, lines)
   preview.col = results.col
 
   return {
-    preview = self.previewer and preview,
+    preview = self.previewer and preview.width > 0 and preview,
     results = results,
     prompt = prompt
   }
@@ -246,7 +251,7 @@ layout_strategies.vertical = function(self, max_columns, max_lines)
   end
 
   return {
-    preview = preview.width > 0 and preview,
+    preview = self.previewer and preview.width > 0 and preview,
     results = results,
     prompt = prompt
   }
diff --git a/lua/telescope/sorters.lua b/lua/telescope/sorters.lua
index 3f9844d..4088ce0 100644
--- a/lua/telescope/sorters.lua
+++ b/lua/telescope/sorters.lua
@@ -198,7 +198,7 @@ end
 sorters.get_generic_fuzzy_sorter = function(opts)
   opts = opts or {}
 
-  local ngram_len = 2
+  local ngram_len = opts.ngram_len or 2
 
   local function overlapping_ngrams(s, n)
     if TelescopeCachedNgrams[s] and TelescopeCachedNgrams[s][n] then
@@ -283,6 +283,30 @@ sorters.get_generic_fuzzy_sorter = function(opts)
   }
 end
 
+sorters.fuzzy_with_index_bias = function(opts)
+  opts = opts or {}
+  opts.ngram_len = 2
+
+  -- TODO: Probably could use a better sorter here.
+  local fuzzy_sorter = sorters.get_generic_fuzzy_sorter(opts)
+
+  return Sorter:new {
+    scoring_function = function(_, prompt, _, entry)
+      local base_score = fuzzy_sorter:score(prompt, entry)
+
+      if base_score == -1 then
+        return -1
+      end
+
+      if base_score == 0 then
+        return entry.index
+      else
+        return math.min(math.pow(entry.index, 0.25), 2) * base_score
+      end
+    end
+  }
+end
+
 -- Bad & Dumb Sorter
 sorters.get_levenshtein_sorter = function()
   return Sorter:new {