fix: use the original sorter again (#209)

Fix #36

telescope.nvim's latest release 0.1.8 does not include the changes in
https://github.com/nvim-telescope/telescope.nvim/pull/2950.
So use again the original implementation.

TODO: remove this when the commit will be included in any release.

lua/frecency/picker.lua

@@ -2,7 +2,7 @@ local State = require "frecency.state"
 local Finder = require "frecency.finder"
 local config = require "frecency.config"
 local fuzzy_sorter = require "frecency.fuzzy_sorter"
-local sorters = require "telescope.sorters"
+local substr_sorter = require "frecency.substr_sorter"
 local log = require "plenary.log"
 local Path = require "plenary.path" --[[@as FrecencyPlenaryPath]]
 local actions = require "telescope.actions"
@@ -106,7 +106,7 @@ function Picker:start(opts)
     prompt_title = "Frecency",
     finder = finder,
     previewer = config_values.file_previewer(opts),
-    sorter = config.matcher == "default" and sorters.get_substr_matcher() or fuzzy_sorter(opts),
+    sorter = config.matcher == "default" and substr_sorter() or fuzzy_sorter(opts),
     on_input_filter_cb = self:on_input_filter_cb(opts),
     attach_mappings = function(prompt_bufnr)
       return self:attach_mappings(prompt_bufnr)

lua/frecency/substr_sorter.lua

@@ -0,0 +1,55 @@
+-- TODO: use this module until telescope's release include this below.
+-- https://github.com/nvim-telescope/telescope.nvim/pull/2950
+
+local sorters = require "telescope.sorters"
+local util = require "telescope.utils"
+
+local substr_highlighter = function(make_display)
+  return function(_, prompt, display)
+    local highlights = {}
+    display = make_display(prompt, display)
+
+    local search_terms = util.max_split(prompt, "%s")
+    local hl_start, hl_end
+
+    for _, word in pairs(search_terms) do
+      hl_start, hl_end = display:find(word, 1, true)
+      if hl_start then
+        table.insert(highlights, { start = hl_start, finish = hl_end })
+      end
+    end
+
+    return highlights
+  end
+end
+
+return function()
+  local make_display = vim.o.smartcase
+      and function(prompt, display)
+        local has_upper_case = not not prompt:match "%u"
+        return has_upper_case and display or display:lower()
+      end
+    or function(_, display)
+      return display:lower()
+    end
+
+  return sorters.Sorter:new {
+    highlighter = substr_highlighter(make_display),
+    scoring_function = function(_, prompt, _, entry)
+      if #prompt == 0 then
+        return 1
+      end
+
+      local display = make_display(prompt, entry.ordinal)
+
+      local search_terms = util.max_split(prompt, "%s")
+      for _, word in pairs(search_terms) do
+        if not display:find(word, 1, true) then
+          return -1
+        end
+      end
+
+      return entry.index
+    end,
+  }
+end