select.lua: select from the watch history with g-h

Implement selection of the entries in the watch history.

--osd-playlist-entry determines whether titles and/or filenames are
shown. But unlike in show-text ${playlist} and select-playlist, "file"
and "both" print full paths because history is much more likely to have
files from completely different directories, so showing the directory
conveys where files are located. This is particularly helpful for
filenames like 1.jpg.

The last entry in the selector deletes the history file, as requested by
Samillion.

DOCS/man/mpv.rst

@@ -328,6 +328,9 @@ g-l
 g-d
     Select an audio device.
 
+g-h
+    Select a file from the watch history. Requires ``--save-watch-history``.
+
 g-w
     Select a file from watch later config files (see `RESUMING PLAYBACK`_) to
     resume playing. Requires ``--write-filename-in-watch-later-config``. This

DOCS/man/options.rst

@@ -1152,7 +1152,8 @@ Watch History
 -------------
 
 ``--save-watch-history``
-    Whether to save which files are played.
+    Whether to save which files are played. These can be then selected with the
+    default ``g-h`` key binding.
 
     .. warning::
 

etc/input.conf

@@ -187,6 +187,7 @@
 #g-e script-binding select/select-edition
 #g-l script-binding select/select-subtitle-line
 #g-d script-binding select/select-audio-device
+#g-h script-binding select/select-watch-history
 #g-w script-binding select/select-watch-later
 #g-b script-binding select/select-binding
 #g-r script-binding select/show-properties

player/lua/select.lua

@@ -18,6 +18,12 @@ License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
 local utils = require "mp.utils"
 local input = require "mp.input"
 
+local options = {
+    history_date_format = "%Y-%m-%d %H:%M:%S",
+}
+
+require "mp.options".read_options(options, nil, function () end)
+
 local function show_warning(message)
     mp.msg.warn(message)
     if mp.get_property_native("vo-configured") then
@@ -353,6 +359,104 @@ mp.add_key_binding(nil, "select-audio-device", function ()
     })
 end)
 
+local function get_history_entry(line, seen, error_message)
+    local entry = utils.parse_json(line)
+
+    if not entry then
+        mp.msg.warn(error_message)
+        return
+    end
+
+    if not entry.path then
+        mp.msg.warn(error_message)
+        return
+    end
+
+    if seen[entry.path] then
+        return
+    end
+
+    seen[entry.path] = true
+
+    local status
+    status, entry.time = pcall(os.date, options.history_date_format, entry.time)
+
+    if not status then
+        -- Lua 5.1 and LuaJIT return invalid formats as is, but Lua 5.2+ errors,
+        -- so also print the returned error message for that case.
+        mp.msg.warn(error_message .. " - " .. entry.time)
+        return
+    end
+
+    return entry
+end
+
+
+local function format_history_entry(entry, osd_playlist_entry)
+    if entry.title and osd_playlist_entry == "title" then
+        return entry.title
+    end
+
+    if entry.title and osd_playlist_entry == "both" then
+        return entry.title .. " (" .. entry.path .. ")"
+    end
+
+    return entry.path
+end
+
+mp.add_key_binding(nil, "select-watch-history", function ()
+    local history_file_path = mp.command_native({"expand-path",
+                                                 mp.get_property("watch-history-path")})
+    local history_file, error_message = io.open(history_file_path)
+    if not history_file then
+        show_warning(mp.get_property_native("save-watch-history")
+                     and error_message
+                     or "Enable --save-watch-history")
+        return
+    end
+
+    local lines = {}
+    for line in history_file:lines() do
+        table.insert(lines, line)
+    end
+    history_file:close()
+
+    local entries = {}
+    local seen = {}
+    local items = {}
+    local osd_playlist_entry = mp.get_property("osd-playlist-entry")
+
+    for i = #lines, 1, -1 do
+        error_message = history_file_path .. ": Parse error at line " .. i
+        local entry = get_history_entry(lines[i], seen, error_message)
+        if entry then
+            entries[#entries + 1] = entry
+            items[#items + 1] = "(" .. entry.time .. ") " ..
+                                format_history_entry(entry, osd_playlist_entry)
+        end
+    end
+
+    items[#items+1] = "Clear history"
+
+    input.select({
+        prompt = "Select a file:",
+        items = items,
+        submit = function (i)
+            if entries[i] then
+                mp.commandv("loadfile", entries[i].path)
+                return
+            end
+
+            error_message = select(2, os.remove(history_file_path))
+            if error_message then
+                show_error(error_message)
+            else
+                mp.osd_message("History cleared.")
+            end
+        end,
+    })
+end)
+
 mp.add_key_binding(nil, "select-watch-later", function ()
     local watch_later_dir = mp.get_property("current-watch-later-dir")