*telescope-frecency.txt*	a telescope extension to use frecency matcher

License: MIT

CONTENTS					   *telescope-frecency-contents*

Introduction		|telescope-frecency-introduction|
Requirements		|telescope-frecency-requirements|
Installation		|telescope-frecency-installation|
Usage			|telescope-frecency-usage|
Command			|telescope-frecency-command|
Function		|telescope-frecency-function|
Configuration		|telescope-frecency-configuration|
Database		|telescope-frecency-database|
Highlight Groups	|telescope-frecency-highlight-groups|
FAQ			|telescope-frecency-faq|
Reference		|telescope-frecency-reference|


==============================================================================
INTRODUCTION				       *telescope-frecency-introduction*

This plugin is a |telescope.nvim| extension that offers intelligent
prioritization when selecting files from your editing history.

Using an implementation of Mozilla's Frecency algorithm (used in Firefox's
address bar), files edited “frecently” are given higher precedence in the list
index.

Frecency implementation
https://firefox-source-docs.mozilla.org/browser/urlbar/ranking.html#frecency-implementation
Firefox's address bar
https://support.mozilla.org/en-US/kb/address-bar-autocomplete-firefox

As the extension learns your editing habits over time, the sorting of the list
is dynamically altered to prioritize the files you're likely to need.

------------------------------------------------------------------------------
Frecency: Sorting by “frequently” and “recency”
				      *telescope-frecency-introduction-frecency*

“Frecency” is a score given to each unique file indexed in a file history
database. A timestamp is recorded once per session when a file is first loaded
into a buffer.

The score is calculated using the age of the 10 (customizable:
|telescope-frecency-configuration-max_timestamps|) most recent
timestamps and the total amount of times that the file has been loaded.

RECENCY VALUES			*telescope-frecency-introduction-recency-values*

THese values are customizable: |telescope-frecency-configuration-recency_values|

┌───────────────┬───────┐
│ Timestamp age │ Value │
├───────────────┼───────┤
│ 4 hours       │ 100   │
│ 1 day         │ 80    │
│ 3 days        │ 60    │
│ 1 week        │ 40    │
│ 1 month       │ 20    │
│ 90 days       │ 10    │
└───────────────┴───────┘

SCORE CALCULATION	     *telescope-frecency-introduction-score-calculation*

Score is calculated by this formula.
>lua
    score = frequency * recency_score / max_number_of_timestamps

------------------------------------------------------------------------------
What about files that are neither “frequent” or “recent”?
			     *telescope-frecency-introduction-non-indexed-files*

Frecency naturally works best for indexed files that have been given a
reasonably high score.

New projects or rarely used files with generic names either don't get listed
at all or can be buried under results with a higher score.

Frecency tackles this with “Workspace Filters”.

WORKSPACE FILTER	      *telescope-frecency-introduction-workspace-filter*

This feature enables you to select from user defined “filter tags” that map to
a directory or collection of directories. Filters are applied by entering
`:workspace_tag:` anywhere in the query. Filter name completion is available by
pressing `<Tab>` after the first `:` character.

When a filter is applied, results are reduced to entries whose path is a
descendant of the workspace directory. The indexed results are optionally
augmented with a listing of “all” files found in a recursive search of the
workspace directory. Non-indexed files are given a score of zero and appear
below the “frecent” entries. When a non-indexed file is opened, it gains a
score value and is available in future “frecent” search results.

If the active buffer (prior to the finder being launched) is attached to an
LSP server, an automatic `LSP` tag is available, which maps to the workspace
directories provided by the language server.


==============================================================================
REQUIREMENTS				       *telescope-frecency-requirements*

- |telescope.nvim| (required)
  https://github.com/nvim-telescope/telescope.nvim
- nvim-web-devicons (optional)
  https://github.com/kyazdani42/nvim-web-devicons
- `fd` or `ripgrep` (optional)
  https://github.com/sharkdp/fd
  https://github.com/BurntSushi/ripgrep

Note: `fd` or `ripgrep` will be used to list up workspace files. They are extremely
faster than the native Lua logic. If you don't have them, it fallbacks to Lua
code automatically. See the detail in
|telescope-frecency-configuration-workspace_scan_cmd|.


==============================================================================
INSTALLATION				       *telescope-frecency-installation*

This is an example for |lazy.nvim|.

lazy.nvim: https://github.com/folke/lazy.nvim
>lua
    -- for lazy.nvim
    {
      "nvim-telescope/telescope-frecency.nvim",
      config = function()
        require("telescope").load_extension "frecency"
      end,
    }

If no database is found when running Neovim with the plugin installed, a new
one is created and entries from |shada| and |v:oldfiles| are automatically
imported.

NOTE: Even if you want to load |telescope.nvim| lazily, you should NOT load
telescope-frecency.nvim lazily. See |telescope-frecency-function-setup|.


==============================================================================
USAGE						      *telescope-frecency-usage*
>vim
    :Telescope frecency
    " Use a specific workspace tag:
    :Telescope frecency workspace=CWD
    " You can use with telescope's options
    :Telescope frecency workspace=CWD path_display={"shorten"} theme=ivy

or to map to a key:
>lua
    vim.keymap.set("n", "<Leader>tf", function()
      require("telescope").extensions.frecency.frecency {}
    end)
    -- Use a specific workspace tag:
    vim.keymap.set("n", "<Leader>tw", function()
      require("telescope").extensions.frecency.frecency {
	workspace = "CWD",
      }
    end)
    -- You can use with telescope's options
    vim.keymap.set("n", "<Leader>tt", function()
      require("telescope").extensions.frecency.frecency {
	workspace = "CWD",
	path_display = { "shorten" },
	theme = "ivy",
      }
    end)

Filter tags are applied by typing the `:tag:` name (adding surrounding colons)
in the finder query. Entering `:<Tab>` will trigger omni completion |compl-omni|.

		       *telescope-frecency-usage-dealing-with-uppercase-letters*
------------------------------------------------------------------------------
Dealing with upper case letters

In default, the sorter always ignores upper case letters in your input string.
But when |'smartcase'| is ON and input string includes one upper case letter
at least, it matches against exact the same as you input.

┌──────────────┬───────────────────────┬───────────────────────┐
│ input string │ |'smartcase'| is ON     │ |'smartcase'| is OFF    │
├──────────────┼───────────────────────┼───────────────────────┤
│ `abc`          │ matches `abc`, `ABC`, `aBc` │ matches `abc`, `ABC`, `aBc` │
│ `aBc`          │ matches `aBc`           │ no match              │
│ `ABC`          │ matches `ABC`           │ no match              │
└──────────────┴───────────────────────┴───────────────────────┘

		      *telescope-frecency-combining-results-outside-this-plugin*
				   *telescope-frecency-live-grep-within-results*
------------------------------------------------------------------------------
Combining results outside this plugin

You can use frecency entries even outside this plugin with
|telescope-frecency-function-query|. For example, you can search any input
string within filenames in frecency results.
>lua
    vim.keymap.set("n", "<Leader>tg", function()
      local frecency = require("telescope").extensions.frecency
      require("telescope.builtin").live_grep {
	-- HACK: `search_dirs` can accept files to grep nevertheless its name
	search_dirs = frecency.query {},
      }
    end, { desc = "Live Grep Frecency" })


==============================================================================
COMMAND						    *telescope-frecency-command*

All commands are for DB maintenance. See also |telescope-frecency-database|.

				     *telescope-frecency-command-frecencydelete*
:FrecencyDelete [path] ~

You can delete entries from DB by this command. This command does not remove
the file itself, only from DB.
>vim
    " delete the current opened file
    :FrecencyDelete
    " delete the supplied path
    :FrecencyDelete /full/path/to/the/file
<
				   *telescope-frecency-command-frecencyvalidate*
:FrecencyValidate[!] ~

You can remove stale entries from the database manually. When `!` is suffixed
(|command-bang|), it never confirms you before removing.
>vim
    " clean DB
    :FrecencyValidate
    " clean DB without prompts to confirm
    :FrecencyValidate!

When you set `false` to |telescope-frecency-configuration-db_safe_mode|, the
prompts are never shown even if you call without the bang.


==============================================================================
FUNCTION					   *telescope-frecency-function*

All functions are exported via `require("telescope").extensions.frecency.*`.
>lua
    -- open frecency picker
    require("telescope").extensions.frecency.frecency {}
<
					  *telescope-frecency-function-frecency*
frecency() ~

Open the frecency picker. See |telescope-frecency-usage| for examples.

					  *telescope-frecency-function-complete*
complete() ~

This is used for completing workspace filters in telescope's prompt. Internal
use only.

					     *telescope-frecency-function-query*
query() ~

Get entries from DB. This is used for combining frecency results outside this
plugin. See |telescope-frecency-combining-results-outside-this-plugin|.
>lua
    local frecency = require("telescope").extensions.frecency
    local entries = frecency.query {}
    -- example results
    [
      "/path/to/any/file1.txt",
      "/more/path/to/any/file2.txt",
      ……
    ]

    -- With record = true, it returns other info for each entry.
    local records = frecency.query { record = true }
    -- example results
    [
      {
        count = 203,
        path = "/path/to/any/file1.txt",
        score = 4872,
        timestamps = { 1719206250, 1719207356, …… },
      },
      ……
    ]

Options:			     *telescope-frecency-function-query-options*
			   *telescope-frecency-function-query-options-direction*
  - `direction`	Default: `"desc"
		`Type: `"asc"|"desc"`
		This specifies the order direction for results.
			       *telescope-frecency-function-query-options-limit*
  - `limit`	Default: `100
		`Type: `integer`
		This limits the number of results.
			       *telescope-frecency-function-query-options-order*
  - `order`	Default: `"score"
		`Type: `"count"|"path"|"score"|"timestamps"`
		This is used to sort results with their properties. With
		`"count"`, `"score"` and `"timestamps"`, when candidates have the
		same value, they will be sorted by `"path"` always in ascending
		order. With `"path"`, the order direction differs by the value
		of `direction`.
			      *telescope-frecency-function-query-options-record*
  - `record`	Default: `false
		Type: `boolean`
		If `false`, it returns results containing filenames with
		absolute paths. If `true`, it contains tables with this
		properties below.

		`count`: Count that the file has been opened.
		`path`: Absolute path for the file.
		`score`: Recency score to be used in frecency picker.
		`timestamps`: UNIX timestamps that the file has been opened at.
			   *telescope-frecency-function-query-options-workspace*
  - `workspace`	`Default: `nil`
		Type: `string?
		This applies |telescope-frecency-introduction-workspace-filter|
		into query results. You can limit candidates to ones that
		exist below the directory specified this value. See also
		|telescope-frecency-usage|.

					     *telescope-frecency-function-setup*
setup() ~

This will be called by |telescope.nvim| for its initialization. You can also
call this to initialize this plugin separated from |telescope.nvim|'s
initialization phase.

This is useful when you want to load |telescope.nvim| lazily, but want to
register opened files as soon as Neovim has started. Example configuration for
|lazy.nvim| is below.
>lua
    {
      "nvim-telescope/telescope-frecency.nvim",
      main = "frecency",
      ---@type FrecencyOpts
      opts = {
	  db_safe_mode = false,
      },
    },

    {
      "nvim-telescope/telescope.nvim",
      -- `cmd` opts makes lazy.nvim load telescope.nvim lazily.
      cmd = { "Telescope" },
      config = function()
	local telescope = require "telescope"
	telescope.setup {
	  extensions = {
	    other_extension = {
	      foo_bar = true,
	    },
	    -- Here you need no configuration opts for frecency because
	    -- you've already done.
	  }
	}
	-- This is still needed.
	telescope.load_extension "frecency"
      end,
    },


==============================================================================
CONFIGURATION				      *telescope-frecency-configuration*

You can call `setup()` with these configuration settings below.
>lua
    -- example settings
    require("telescope").setup {
      extensions = {
	frecency = {
	  auto_validate = false,
	  matcher = "fuzzy",
	  path_display = { "filename_first" },
	},
      },
    }
<
				 *telescope-frecency-configuration-frecencyopts*
								  *FrecencyOpts*
`FrecencyOpts` is a convenient type to use your own configuration. With using
this in the type annotation, you can complete items by LSP in writing.

NOTE: You need a properly configured Language Server for this feature such as
lua-ls. https://github.com/LuaLS/lua-language-server
>lua
    require("telescope").setup {
      extensions = {
	---@type FrecencyOpts
	frecency = {
	  auto_validate = false,
	  -- …… other configs
	}
      },
    }
<
			       *telescope-frecency-configuration-config.setup()*
You can change this configuration after loading plugins by `config.setup()`.
>lua
    require("frecency.config").setup {
      auto_validate = true,
      ignore_patterns = { "*/.git", "*/.git/*", "*/.DS_Store" },
    }
<
This function always resets the config to default values, and applies supplied
ones. So you should set the whole configs for calling this function.

			        *telescope-frecency-configuration-auto_validate*
auto_validate ~

Default: `true`
Type: `boolean`

If `true`, it removes stale entries count over than
|telescope-frecency-configuration-db_validate_threshold|.

				      *telescope-frecency-configuration-db_root*
db_root ~

Default: `vim.fn.stdpath "state"`
Type: `string`

Path to the parent directory of custom database location. Defaults to
|$XDG_STATE_HOME|/nvim (see |stdpath()|) if unset.

NOTE: The default value was `vim.fn.stdpath "data"`. If you doesn't set this
option and you have DB in `vim.fn.stdpath "data"` instead of
`vim.fn.stdpath "state"`, it uses the one in the old path for backward
compatibility. See the detail in the issue below.
https://github.com/nvim-telescope/telescope-frecency.nvim/issues/200

				 *telescope-frecency-configuration-db_safe_mode*
db_safe_mode ~

Default: `true`
Type: `boolean`

If `true`, it shows confirmation dialog by |vim.ui.select()| before validating DB.
See the note for |telescope-frecency-database|.

			*telescope-frecency-configuration-db_validate_threshold*
db_validate_threshold ~

Default: `10`
Type: `integer`

It will remove entries when stale ones exist more than this count.

					*telescope-frecency-configuration-debug*
debug ~

Default: `false`
Type: `boolean`

This plugin uses `plenary.log` to log debugging messages. You should set this to
`true` and set environmental variable `DEBUG_PLENARY` to see debug messages.
>bash
    # Launch Neovim with DEBUG_PLENARY=1 and set `debug = true` and you can
    # see debug messages.
    env DEBUG_PLENARY=1 nvim
<
			    *telescope-frecency-configuration-default_workspace*
default_workspace ~

Default: `nil`
Type: `string?`

Default workspace tag to filter. For example, entries are filtered to ones in
the current directory when you set this to `"CWD"`. This can be overwritten in
querying by specifying another filter like `:FOO:`.

			     *telescope-frecency-configuration-disable_devicons*
disable_devicons ~

Default: `false`
Type: `boolean`

Disable devicons (if available).

			  *telescope-frecency-configuration-hide_current_buffer*
hide_current_buffer ~

Default: `false`
Type: `boolean`

If `true`, it does not show the filename in the current buffer in candidates.

			     *telescope-frecency-configuration-filter_delimiter*
filter_delimiter ~

Delimiters to indicate the filter like `:CWD:`.

			      *telescope-frecency-configuration-ignore_patterns*
ignore_patterns ~

Default:
  for non-Windows: `{ "*.git/*", "*/tmp/*", "term://*" }`
  for Windows: `{ [[*.git\*]], [[*\tmp\*]], "term://*" }`
Type: `string[]`

Glob patterns in this table control which files are indexed (and subsequently
which you'll see in the finder results).

NOTE: In registering, |telescope-frecency-configuration-ignore_register| is
applied before this patterns

			      *telescope-frecency-configuration-ignore_register*
ignore_register ~

Default: `nil`
Type: `fun(bufnr: integer): boolean`

In opening buffers, it registers the filename and timestamps into DB to
calculate frecency scores later. `ignore_register` can take a buffer number
and you can control whether the file should be registered or not.

For example, you can ignore |'nobuflisted'| buffers to register with this below.
>lua
    telescope.setup {
      extensions = {
	frecency = {
	  ignore_register = function(bufnr)
	    return not vim.bo[bufnr].buflisted
	  end,
	}
      },
    }
<
NOTE: In registering, |telescope-frecency-configuration-ignore_patterns| is also
applied in addition to this function.

				      *telescope-frecency-configuration-matcher*
matcher ~

Default: `"default"`
Type: `"default"|"fuzzy"`

WARNING: This option is highly experimental.

In default, it matches against candidates by the so-called “substr matcher”,
that is, you should input characters ordered properly. If you set here with
`"fuzzy"`, it uses “fzy matcher” implemented in |telescope.nvim| itself, and
combines the result with recency scores.

fzy matcher: https://github.com/jhawthorn/fzy

With this, you can select candidates fully fuzzily, besides that, can select
easily ones that has higher recency scores.

See the discussion in this issue.
https://github.com/nvim-telescope/telescope-frecency.nvim/issues/165

			       *telescope-frecency-configuration-max_timestamps*
max_timestamps ~

Default: `10`
Type: `integer`

Set the max count of timestamps DB keeps when you open files. It ignores the
value and use `10` if you set less than or equal to `0`.

Warning: When you reduce the value of this option, it removes old timestamps
when you open the file. It is reasonable to set this value more than or equal
to the default value: `10`.

				 *telescope-frecency-configuration-path_display*
path_display ~

Default: `nil`
Type: same as |telescope.defaults.path_display|

Overwrite |telescope.defaults.path_display|. This setting will be used by
these priorities below.

1. Option specified with the command or Lua code. Such as, >vim
    :Telescope frecency path_display={"absolute"}
<   or >lua
    require("telescope").extensions.frecency.frecency {
      path_display = { "absolute" },
    }

2. `opts.extensions.frecency.path_display` in setup.
3. `opts.defaults.path_display` in setup.
>lua
    require("telescope").setup {
      defaults = {
	-- This has the 3rd precedence.
	path_display = { "absolute" },
      },
      extensions = {
	frecency = {
	  -- This has the 2nd precedence.
	  path_display = { "shorten" },
	},
      },
    }
<
			       *telescope-frecency-configuration-recency_values*
recency_values ~

Default: >lua
    {
      { age = 240, value = 100 }, -- past 4 hours
      { age = 1440, value = 80 }, -- past day
      { age = 4320, value = 60 }, -- past 3 days
      { age = 10080, value = 40 }, -- past week
      { age = 43200, value = 20 }, -- past month
      { age = 129600, value = 10 }, -- past 90 days
    }
Type: `{ age: integer, value: integer }[]`

Set weighting factors for calculating “frecency”. This option does not affect
values already recorded in DB. So you can change these values without spoiling
data.

			     *telescope-frecency-configuration-scoring_function*
scoring_function ~

Default: >lua
    function(recency, fzy_score)
      local score = (10 / (recency == 0 and 1 or recency)) - 1 / fzy_score
      return score == -1 and -1.000001 or score
    end
Type: `fun(recency: integer, fzy_score: number): number`

WARNING: This option is highly experimental.

This will be used only when |telescope-frecency-configuration-matcher| is
`"fuzzy"`. You can customize the logic to adjust scores between “fzy matcher”
scores and recency ones.

			   *telescope-frecency-configuration-show_filter_column*
show_filter_column ~

Default: `true`
Type: `boolean|string[]`

Show the path of the active filter before file paths. In default, it uses the
tail of paths for `"LSP"` and `"CWD"` tags. YOu can configure this by setting a
table for this option.
>lua
    -- show the tail for "LSP", "CWD" and "FOO"
    show_filter_column = { "LSP", "CWD", "FOO" }
<
				  *telescope-frecency-configuration-show_scores*
show_scores ~

Default: `false`
Type: `boolean`

To see scores calculated by the algorithm in the results, set this to `true`.

			       *telescope-frecency-configuration-show_unindexed*
show_unindexed ~

Default: `true`
Type: `boolean`

Determines if non-indexed files are included in workspace filter results.

			   *telescope-frecency-configuration-workspace_scan_cmd*
workspace_scan_cmd ~

Default: `nil`
Type: `"LUA"|string[]|nil`

With the default value: `nil`, it uses these ways below to make entries for
workspace files. It tries in order until it works successfully.

1. `fdfind -Htf -E .git`
2. `fd -Htf -E .git`
3. `rg -.g '!.git' --files`
4. Native Lua code (old way)

If you like another commands, set them to this option, like
`workspace_scan_cmd = { "find", ".", "-type", "f" }`.

NOTE: When the plugin uses “4. Native Lua code”, it uses
|telescope-frecency-configuration-ignore_patterns| to ignore candidates from
listed entries. With other ways, such as `rg` and `fd`, it does not use the option
because of performance consideration.

				   *telescope-frecency-configuration-workspaces*
workspaces ~

Default: `{}`
Type: `table<string, string>`

This table contains mappings of `workspace_tag` → `workspace_directory`. The key
corresponds to the `:tag_name` used to select the filter in queries. The value
corresponds to the top level directory by which results will be filtered.
>lua
    -- example configuration
    workspaces = {
      ["conf"] = "/home/my_username/.config",
      ["data"] = "/home/my_username/.local/share",
      ["project"] = "/home/my_username/projects",
      ["wiki"] = "/home/my_username/wiki",
    }


==============================================================================
DATABASE					   *telescope-frecency-database*

------------------------------------------------------------------------------
Location				  *telescope-frecency-database-location*

The default location for the database is `$XDG_DATA_HOME/nvim` (e.g.
`~/.local/share/nvim` on Linux). This can be configured with the
|telescope-frecency-configuration-db_root| config option. The filename for the
database is `file_frecency.bin` (not configurable).

------------------------------------------------------------------------------
Maintenance			       *telescope-frecency-database-maintenance*

By default, this plugin will prune files that no longer exist from the
database. In certain workflows, switching branches in a repository, that
behavior might not be desired. The following configuration control this
behavior.

- `db_safe_mode
  When this is enabled, the user will be prompted before any entries are
  removed from the database.
- `auto_validate
  When this is `false`, stale entries will never be removed automatically.

If you want not to be bothered with such things and to remove stale results
silently, set these below.
>lua
    require("telescope").setup {
      extensions = {
	frecency = {
	  db_safe_mode = false,
	  -- auto_validate is `true` in default
	},
      },
    }

------------------------------------------------------------------------------
Compatibility			     *telescope-frecency-database-compatibility*

The former version of this plugin has used SQLite3 library to store data. The
PR #172 has removed the whole code for that.

feat!: remove code for SQLite by delphinus · Pull Request #172
https://github.com/nvim-telescope/telescope-frecency.nvim/pull/172

If you prefer the old SQLite database, you should lock the version to `a3e818d`
with your favorite plugin manager.
>lua
    -- example for lazy.nvim
    {
      "nvim-telescope/telescope-frecency.nvim",
      commit = "a3e818d001baad9ee2f6800d3bbc71c4275364ae",
    }


==============================================================================
HIGHLIGHT GROUPS			   *telescope-frecency-highlight-groups*

This plugin defined these highlight groups below. You can set your own colors
before loading plugins.

		     *telescope-frecency-highlight-groups-telescopebufferloaded*
TelescopeBufferLoaded ~

Default: link to |hl-String|

This is used to highlight the filename already opened in buffers.

		    *telescope-frecency-highlight-groups-telescopepathseparator*
TelescopePathSeparator ~

Default: link to |hl-Directory|

This is used to highlight path separators: `/` (non-Windows), `\` (Windows).

		   *telescope-frecency-highlight-groups-telescopefrecencyscores*
TelescopeFrecencyScores ~

Default: link to |hl-Number|

This is used to highlight scores in the results.

		      *telescope-frecency-highlight-groups-telescopequeryfilter*
TelescopeQueryFilter ~

Default: link to |hl-WildMenu|

This is used to highlight query filter such as `:CWD:`.


==============================================================================
FAQ							*telescope-frecency-faq*

			     *telescope-frecency-faq-removenentriesfromdatabase*
“remove n entries from database?” dialog appears in startup ~

This dialog informs you that this plugin will delete entries because stale
ones exist in DB.

If you feel this annoying, you can disable it by config. See
|telescope-frecency-configuration-db_safe_mode|,
|telescope-frecency-configuration-auto_validate|.
>lua
    {
      "nvim-telescope/telescope.nvim",
      config = function()
	local telescope = require "telescope"
	telescope.setup {
	  extensions = {
	    frecency = {
	      -- completely disable the dialog
	      db_safe_mode = false,
	    },
	  },
	}
	telescope.load_extension "frecency"
      end,
    }

==============================================================================
REFERENCE					  *telescope-frecency-reference*

Mozilla: Frecency algorithm
https://developer.mozilla.org/en-US/docs/Mozilla/Tech/Places/Frecency_algorithm
(Web Archive)
https://web.archive.org/web/20210421120120/https://developer.mozilla.org/en-US/docs/Mozilla/Tech/Places/Frecency_algorithm


vim:tw=78:fo=tcq2mM:ts=8:ft=help:norl:noet