feat: add JSON output for query() (#262)

This makes it be enable to do this.

```bash
$ nvim --headless +'=require("frecency").query { limit = 3, json = true }' +q | jq .
[
  "/path/to/most/opened/file",
  "/path/to/second/file",
  "/path/to/third/file"
]
```

* chore: add `debug_timer` option to log in timer

* fix: wait synchronously for DB not in coroutine

* feat: add `json` option to dump JSON for DB

lua/frecency/config.lua

@@ -9,6 +9,7 @@ local os_util = require "frecency.os_util"
 ---@field db_safe_mode? boolean default: true
 ---@field db_validate_threshold? integer default: 10
 ---@field debug? boolean default: false
+---@field debug_timer? boolean default: false
 ---@field default_workspace? string default: nil
 ---@field disable_devicons? boolean default: false
 ---@field filter_delimiter? string default: ":"
@@ -39,6 +40,7 @@ local Config = {}
 ---@field db_safe_mode boolean default: true
 ---@field db_validate_threshold integer default: 10
 ---@field debug boolean default: false
+---@field debug_timer boolean default: false
 ---@field default_workspace? string default: nil
 ---@field disable_devicons boolean default: false
 ---@field filter_delimiter string default: ":"
@@ -66,6 +68,7 @@ Config.new = function()
     db_safe_mode = true,
     db_validate_threshold = true,
     debug = true,
+    debug_timer = true,
     default_workspace = true,
     disable_devicons = true,
     filter_delimiter = true,
@@ -106,6 +109,7 @@ Config.default_values = {
   db_safe_mode = true,
   db_validate_threshold = 10,
   debug = false,
+  debug_timer = false,
   default_workspace = nil,
   disable_devicons = false,
   filter_delimiter = ":",

lua/frecency/database/table.lua

@@ -1,4 +1,6 @@
+local log = require "frecency.log"
 local timer = require "frecency.timer"
+local wait = require "frecency.wait"
 local lazy_require = require "frecency.lazy_require"
 local async = lazy_require "plenary.async" --[[@as FrecencyPlenaryAsync]]
 
@@ -24,7 +26,15 @@ end
 ---@param key string
 function Table:__index(key)
   if key == "records" and not rawget(self, "is_ready") then
-    Table.wait_ready(self)
+    local is_async = not not coroutine.running()
+    if is_async then
+      Table.wait_ready(self)
+    else
+      log.debug "need wait() for wait_ready()"
+      wait(function()
+        Table.wait_ready(self)
+      end)
+    end
   end
   return vim.F.if_nil(rawget(self, key), Table[key])
 end

lua/frecency/klass.lua

@@ -200,6 +200,7 @@ end
 
 ---@class FrecencyQueryOpts
 ---@field direction? "asc"|"desc" default: "desc"
+---@field json? boolean default: false
 ---@field limit? integer default: 100
 ---@field order? FrecencyQueryOrder default: "score"
 ---@field record? boolean default: false
@@ -213,10 +214,11 @@ end
 
 ---@param opts? FrecencyQueryOpts
 ---@param epoch? integer
----@return FrecencyQueryEntry[]|string[]
+---@return string|FrecencyQueryEntry[]|string[]
 function Frecency:query(opts, epoch)
   opts = vim.tbl_extend("force", {
     direction = "desc",
+    json = false,
     limit = 100,
     order = "score",
     record = false,
@@ -235,9 +237,9 @@ function Frecency:query(opts, epoch)
     return entry.path
   end, entries)
   if #results > opts.limit then
-    return vim.list_slice(results, 1, opts.limit)
+    results = vim.list_slice(results, 1, opts.limit)
   end
-  return results
+  return opts.json and vim.json.encode(results) or results
 end
 
 ---@private

lua/frecency/timer.lua

@@ -23,6 +23,9 @@ function M.track(event)
       return stats._stats.times[key] and make_key((num or 1) + 1) or key
     end
     stats.track(make_key())
+    if config.debug_timer then
+      log.debug(event)
+    end
   end
 end