scripting: add mp.input

This lets scripts get textual input from the user using console.lua.

8 files changed, 378 insertions, 42 deletions

diff --git a/DOCS/interface-changes.rst b/DOCS/interface-changes.rst
index 558392b00f..d3a48804fe 100644
--- a/DOCS/interface-changes.rst
+++ b/DOCS/interface-changes.rst
@@ -36,6 +36,7 @@ Interface changes
     - `--screenshot-avif-opts` defaults to lossless screenshot
     - rename key `MP_KEY_BACK` to `MP_KEY_GO_BACK`
     - add `--sub-filter-sdh-enclosures` option
+    - added the `mp.input` scripting API to query the user for textual input
  --- mpv 0.37.0 ---
     - `--save-position-on-quit` and its associated commands now store state files
       in %LOCALAPPDATA% instead of %APPDATA% directory by default on Windows.
diff --git a/DOCS/man/javascript.rst b/DOCS/man/javascript.rst
index bdbb04b198..0edb01f674 100644
--- a/DOCS/man/javascript.rst
+++ b/DOCS/man/javascript.rst
@@ -27,16 +27,17 @@ otherwise, the documented Lua options, script directories, loading, etc apply to
 JavaScript files too.
 
 Script initialization and lifecycle is the same as with Lua, and most of the Lua
-functions at the modules ``mp``, ``mp.utils``, ``mp.msg`` and ``mp.options`` are
-available to JavaScript with identical APIs - including running commands,
-getting/setting properties, registering events/key-bindings/hooks, etc.
+functions in the modules ``mp``, ``mp.utils``, ``mp.msg``, ``mp.options`` and
+``mp.input`` are available to JavaScript with identical APIs - including running
+commands, getting/setting properties, registering events/key-bindings/hooks,
+etc.
 
 Differences from Lua
 --------------------
 
-No need to load modules. ``mp``, ``mp.utils``,  ``mp.msg`` and ``mp.options``
-are preloaded, and you can use e.g. ``var cwd = mp.utils.getcwd();`` without
-prior setup.
+No need to load modules. ``mp``, ``mp.utils``,  ``mp.msg``, ``mp.options`` and
+``mp.input`` are preloaded, and you can use e.g. ``var cwd =
+mp.utils.getcwd();`` without prior setup.
 
 Errors are slightly different. Where the Lua APIs return ``nil`` for error,
 the JavaScript ones return ``undefined``. Where Lua returns ``something, error``
@@ -195,6 +196,16 @@ meta-paths like ``~~/foo`` (other JS file functions do expand meta paths).
 ``mp.options.read_options(obj [, identifier [, on_update]])`` (types:
 string/boolean/number)
 
+``mp.input.get(obj)`` (LE)
+
+``mp.input.terminate()``
+
+``mp.input.log(message, style)``
+
+``mp.input.log_error(message)``
+
+``mp.input.set_log(log)``
+
 Additional utilities
 --------------------
 
diff --git a/DOCS/man/lua.rst b/DOCS/man/lua.rst
index 5708e19372..ac062aec6c 100644
--- a/DOCS/man/lua.rst
+++ b/DOCS/man/lua.rst
@@ -862,6 +862,88 @@ strictly part of the guaranteed API.
     Turn the given value into a string. Formats tables and their contents. This
     doesn't do anything special; it is only needed because Lua is terrible.
 
+mp.input functions
+--------------------
+
+This module lets scripts get textual input from the user using the console
+REPL.
+
+``input.get(table)``
+    Show the console to let the user enter text.
+
+    The following entries of ``table`` are read:
+
+    ``prompt``
+        The string to be displayed before the input field.
+
+    ``submit``
+        A callback invoked when the user presses Enter. The first argument is
+        the text in the console. You can close the console from within the
+        callback by calling ``input.terminate()``. If you don't, the console
+        stays open and the user can input more text.
+
+    ``opened``
+        A callback invoked when the console is shown. This can be used to
+        present a list of options with ``input.set_log()``.
+
+    ``edited``
+        A callback invoked when the text changes. This can be used to filter a
+        list of options based on what the user typed with ``input.set_log()``,
+        like dmenu does. The first argument is the text in the console.
+
+    ``complete``
+        A callback invoked when the user presses TAB. The first argument is the
+        text before the cursor. The callback should return a table of the string
+        candidate completion values and the 1-based cursor position from which
+        the completion starts. console.lua will filter the suggestions beginning
+        with the the text between this position and the cursor, sort them
+        alphabetically, insert their longest common prefix, and show them when
+        there are multiple ones.
+
+    ``closed``
+        A callback invoked when the console is hidden, either because
+        ``input.terminate()`` was invoked from the other callbacks, or because
+        the user closed it with a key binding. The first argument is the text in
+        the console, and the second argument is the cursor position.
+
+    ``default_text``
+        A string to pre-fill the input field with.
+
+    ``cursor_position``
+        The initial cursor position, starting from 1.
+
+    ``id``
+        An identifier that determines which input history and log buffer to use
+        among the ones stored for ``input.get()`` calls. The input histories
+        and logs are stored in memory and do not persist across different mpv
+        invocations. Defaults to the calling script name with ``prompt``
+        appended.
+
+``input.terminate()``
+    Close the console.
+
+``input.log(message, style)``
+    Add a line to the log buffer. ``style`` can contain additional ASS tags to
+    apply to ``message``.
+
+``input.log_error(message)``
+    Helper to add a line to the log buffer with the same color as the one the
+    console uses for errors. Useful when the user submits invalid input.
+
+``input.set_log(log)``
+    Replace the entire log buffer.
+
+    ``log`` is a table of strings, or tables with ``text`` and ``style`` keys.
+
+    Example:
+
+    ::
+
+        input.set_log({
+            "regular text",
+            { style = "{\\c&H7a77f2&}", text = "error text" }
+        })
+
 Events
 ------
 
diff --git a/player/javascript/defaults.js b/player/javascript/defaults.js
index be4fca61c9..cc2ca3f232 100644
--- a/player/javascript/defaults.js
+++ b/player/javascript/defaults.js
@@ -643,6 +643,53 @@ function read_options(opts, id, on_update, conf_override) {
 mp.options = { read_options: read_options };
 
 /**********************************************************************
+*  input
+*********************************************************************/
+mp.input = {
+    get: function(t) {
+        mp.commandv("script-message-to", "console", "get-input", mp.script_name,
+                    JSON.stringify({
+                        prompt: t.prompt,
+                        default_text: t.default_text,
+                        cursor_position: t.cursor_position,
+                        id: t.id,
+                    }));
+
+        mp.register_script_message("input-event", function (type, text, cursor_position) {
+            if (t[type]) {
+                var result = t[type](text, cursor_position);
+
+                if (type == "complete" && result) {
+                    mp.commandv("script-message-to", "console", "complete",
+                                JSON.stringify(result[0]), result[1]);
+                }
+            }
+
+            if (type == "closed") {
+                mp.unregister_script_message("input-event");
+            }
+        })
+
+        return true;
+    },
+    terminate: function () {
+        mp.commandv("script-message-to", "console", "disable");
+    },
+    log: function (message, style) {
+        mp.commandv("script-message-to", "console", "log",
+                    JSON.stringify({ text: message, style: style }));
+    },
+    log_error: function (message) {
+        mp.commandv("script-message-to", "console", "log",
+                    JSON.stringify({ text: message, error: true }));
+    },
+    set_log: function (log) {
+        mp.commandv("script-message-to", "console", "set-log",
+                    JSON.stringify(log));
+    }
+}
+
+/**********************************************************************
  *  various
  *********************************************************************/
 g.print = mp.msg.info;  // convenient alias
diff --git a/player/lua.c b/player/lua.c
index 549d8d9e55..b2548387f6 100644
--- a/player/lua.c
+++ b/player/lua.c
@@ -61,6 +61,9 @@ static const char * const builtin_lua_scripts[][2] = {
     {"mp.assdraw",
 #   include "player/lua/assdraw.lua.inc"
     },
+    {"mp.input",
+#   include "player/lua/input.lua.inc"
+    },
     {"mp.options",
 #   include "player/lua/options.lua.inc"
     },
diff --git a/player/lua/console.lua b/player/lua/console.lua
index 1ddfca151a..92c2195623 100644
--- a/player/lua/console.lua
+++ b/player/lua/console.lua
@@ -82,11 +82,17 @@ local insert_mode = false
 local pending_update = false
 local line = ''
 local cursor = 1
-local history = {}
+local default_prompt = '>'
+local prompt = default_prompt
+local default_id = 'default'
+local id = default_id
+local histories = {[id] = {}}
+local history = histories[id]
 local history_pos = 1
-local log_buffer = {}
+local log_buffers = {[id] = {}}
 local key_bindings = {}
 local global_margins = { t = 0, b = 0 }
+local input_caller
 
 local suggestion_buffer = {}
 local selected_suggestion_index
@@ -94,6 +100,8 @@ local completion_start_position
 local completion_append
 local file_commands = {}
 local path_separator = platform == 'windows' and '\\' or '/'
+local completion_old_line
+local completion_old_cursor
 
 local update_timer = nil
 update_timer = mp.add_periodic_timer(0.05, function()
@@ -190,6 +198,7 @@ end
 
 -- Add a line to the log buffer (which is limited to 100 lines)
 function log_add(style, text)
+    local log_buffer = log_buffers[id]
     log_buffer[#log_buffer + 1] = { style = style, text = text }
     if #log_buffer > 100 then
         table.remove(log_buffer, 1)
@@ -321,7 +330,7 @@ local function print_to_terminal()
     end
 
     local log = ''
-    for _, log_line in ipairs(log_buffer) do
+    for _, log_line in ipairs(log_buffers[id]) do
         log = log .. log_line.text
     end
 
@@ -337,8 +346,9 @@ local function print_to_terminal()
         after_cur = ' '
     end
 
-    mp.osd_message(log .. suggestions .. '> ' .. before_cur .. '\027[7m' ..
-                   after_cur:sub(1, 1) .. '\027[0m' .. after_cur:sub(2), 999)
+    mp.osd_message(log .. suggestions .. prompt .. ' ' .. before_cur ..
+                  '\027[7m' .. after_cur:sub(1, 1) .. '\027[0m' ..
+                   after_cur:sub(2), 999)
 end
 
 -- Render the REPL and console as an ASS OSD
@@ -407,6 +417,7 @@ function update()
     local suggestion_ass = style .. styles.suggestion .. suggestions
 
     local log_ass = ''
+    local log_buffer = log_buffers[id]
     local log_messages = #log_buffer
     local log_max_lines = math.max(0, lines_max - rows)
     if log_max_lines < log_messages then
@@ -423,7 +434,7 @@ function update()
     if #suggestions > 0 then
         ass:append(suggestion_ass .. '\\N')
     end
-    ass:append(style .. '> ' .. before_cur)
+    ass:append(style .. ass_escape(prompt) .. ' ' .. before_cur)
     ass:append(cglyph)
     ass:append(style .. after_cur)
 
@@ -432,7 +443,7 @@ function update()
     ass:new_event()
     ass:an(1)
     ass:pos(2, screeny - 2 - global_margins.b * screeny)
-    ass:append(style .. '{\\alpha&HFF&}> ' .. before_cur)
+    ass:append(style .. '{\\alpha&HFF&}' .. ass_escape(prompt) .. ' ' .. before_cur)
     ass:append(cglyph)
     ass:append(style .. '{\\alpha&HFF&}' .. after_cur)
 
@@ -446,12 +457,28 @@ function set_active(active)
         repl_active = true
         insert_mode = false
         mp.enable_key_bindings('console-input', 'allow-hide-cursor+allow-vo-dragging')
-        mp.enable_messages('terminal-default')
         define_key_bindings()
+
+        if not input_caller then
+            prompt = default_prompt
+            id = default_id
+            history = histories[id]
+            history_pos = #history + 1
+            mp.enable_messages('terminal-default')
+        end
     else
         repl_active = false
+        suggestion_buffer = {}
         undefine_key_bindings()
         mp.enable_messages('silent:terminal-default')
+
+        if input_caller then
+            mp.commandv('script-message-to', input_caller, 'input-event',
+                        'closed', line, cursor)
+            input_caller = nil
+            line = ''
+            cursor = 1
+        end
         collectgarbage()
     end
     update()
@@ -513,6 +540,16 @@ function len_utf8(str)
     return len
 end
 
+local function handle_edit()
+    suggestion_buffer = {}
+    update()
+
+    if input_caller then
+        mp.commandv('script-message-to', input_caller, 'input-event', 'edited',
+                    line)
+    end
+end
+
 -- Insert a character at the current cursor position (any_unicode)
 function handle_char_input(c)
     if insert_mode then
@@ -521,8 +558,7 @@ function handle_char_input(c)
         line = line:sub(1, cursor - 1) .. c .. line:sub(cursor)
     end
     cursor = cursor + #c
-    suggestion_buffer = {}
-    update()
+    handle_edit()
 end
 
 -- Remove the character behind the cursor (Backspace)
@@ -531,16 +567,14 @@ function handle_backspace()
     local prev = prev_utf8(line, cursor)
     line = line:sub(1, prev - 1) .. line:sub(cursor)
     cursor = prev
-    suggestion_buffer = {}
-    update()
+    handle_edit()
 end
 
 -- Remove the character in front of the cursor (Del)
 function handle_del()
     if cursor > line:len() then return end
     line = line:sub(1, cursor - 1) .. line:sub(next_utf8(line, cursor))
-    suggestion_buffer = {}
-    update()
+    handle_edit()
 end
 
 -- Toggle insert mode (Ins)
@@ -568,8 +602,7 @@ function clear()
     cursor = 1
     insert_mode = false
     history_pos = #history + 1
-    suggestion_buffer = {}
-    update()
+    handle_edit()
 end
 
 -- Close the REPL if the current line is empty, otherwise delete the next
@@ -642,20 +675,25 @@ end
 
 -- Run the current command and clear the line (Enter)
 function handle_enter()
-    if line == '' then
+    if line == '' and input_caller == nil then
         return
     end
-    if history[#history] ~= line then
+    if history[#history] ~= line and line ~= '' then
         history_add(line)
     end
 
-    -- match "help [<text>]", return <text> or "", strip all whitespace
-    local help = line:match('^%s*help%s+(.-)%s*$') or
-                 (line:match('^%s*help$') and '')
-    if help then
-        help_command(help)
+    if input_caller then
+        mp.commandv('script-message-to', input_caller, 'input-event', 'submit',
+                    line)
     else
-        mp.command(line)
+        -- match "help [<text>]", return <text> or "", strip all whitespace
+        local help = line:match('^%s*help%s+(.-)%s*$') or
+                     (line:match('^%s*help$') and '')
+        if help then
+            help_command(help)
+        else
+            mp.command(line)
+        end
     end
 
     clear()
@@ -1025,6 +1063,14 @@ function complete(backwards)
         return
     end
 
+    if input_caller then
+        completion_old_line = line
+        completion_old_cursor = cursor
+        mp.commandv('script-message-to', input_caller, 'input-event',
+                    'complete', line:sub(1, cursor - 1))
+        return
+    end
+
     local before_cur = line:sub(1, cursor - 1)
     local after_cur = line:sub(cursor)
 
@@ -1111,8 +1157,7 @@ function del_word()
     before_cur = before_cur:gsub('[^%s]+%s*$', '', 1)
     line = before_cur .. after_cur
     cursor = before_cur:len() + 1
-    suggestion_buffer = {}
-    update()
+    handle_edit()
 end
 
 -- Delete from the cursor to the end of the word (Ctrl+Del)
@@ -1124,28 +1169,25 @@ function del_next_word()
 
     after_cur = after_cur:gsub('^%s*[^%s]+', '', 1)
     line = before_cur .. after_cur
-    suggestion_buffer = {}
-    update()
+    handle_edit()
 end
 
 -- Delete from the cursor to the end of the line (Ctrl+K)
 function del_to_eol()
     line = line:sub(1, cursor - 1)
-    suggestion_buffer = {}
-    update()
+    handle_edit()
 end
 
 -- Delete from the cursor back to the start of the line (Ctrl+U)
 function del_to_start()
     line = line:sub(cursor)
     cursor = 1
-    suggestion_buffer = {}
-    update()
+    handle_edit()
 end
 
 -- Empty the log buffer of all messages (Ctrl+L)
 function clear_log_buffer()
-    log_buffer = {}
+    log_buffers[id] = {}
     update()
 end
 
@@ -1212,8 +1254,7 @@ function paste(clip)
     local after_cur = line:sub(cursor)
     line = before_cur .. text .. after_cur
     cursor = cursor + text:len()
-    suggestion_buffer = {}
-    update()
+    handle_edit()
 end
 
 -- List of input bindings. This is a weird mashup between common GUI text-input
@@ -1318,11 +1359,95 @@ mp.add_key_binding(nil, 'enable', function()
     set_active(true)
 end)
 
+mp.register_script_message('disable', function()
+    set_active(false)
+end)
+
 -- Add a script-message to show the REPL and fill it with the provided text
 mp.register_script_message('type', function(text, cursor_pos)
     show_and_type(text, cursor_pos)
 end)
 
+mp.register_script_message('get-input', function (script_name, args)
+    if repl_active then
+        return
+    end
+
+    input_caller = script_name
+    args = utils.parse_json(args)
+    prompt = args.prompt or default_prompt
+    line = args.default_text or ''
+    cursor = tonumber(args.cursor_position) or line:len() + 1
+    id = args.id or script_name .. prompt
+    if histories[id] == nil then
+        histories[id] = {}
+        log_buffers[id] = {}
+    end
+    history = histories[id]
+    history_pos = #history + 1
+
+    set_active(true)
+    mp.commandv('script-message-to', input_caller, 'input-event', 'opened')
+end)
+
+mp.register_script_message('log', function (message)
+    -- input.get's edited handler is invoked after submit, so avoid modifying
+    -- the default log.
+    if input_caller == nil then
+        return
+    end
+
+    message = utils.parse_json(message)
+
+    log_add(message.error and styles.error or message.style or '',
+            message.text .. '\n')
+end)
+
+mp.register_script_message('set-log', function (log)
+    if input_caller == nil then
+        return
+    end
+
+    log = utils.parse_json(log)
+    log_buffers[id] = {}
+
+    for i = 1, #log do
+        if type(log[i]) == 'table' then
+            log[i].text = log[i].text .. '\n'
+            log_buffers[id][i] = log[i]
+        else
+            log_buffers[id][i] = {
+                style = '',
+                text = log[i] .. '\n',
+            }
+        end
+    end
+
+    update()
+end)
+
+mp.register_script_message('complete', function(list, start_pos)
+    if line ~= completion_old_line or cursor ~= completion_old_cursor then
+        return
+    end
+
+    local completions, prefix = complete_match(line:sub(start_pos, cursor),
+                                               utils.parse_json(list))
+    local before_cur = line:sub(1, start_pos - 1) .. prefix
+    local after_cur = line:sub(cursor)
+    cursor = before_cur:len() + 1
+    line = before_cur .. after_cur
+
+    if #completions > 1 then
+        suggestion_buffer = completions
+        selected_suggestion_index = 0
+        completion_start_position = start_pos
+        completion_append = ''
+    end
+
+    update()
+end)
+
 -- Redraw the REPL when the OSD size changes. This is needed because the
 -- PlayRes of the OSD will need to be adjusted.
 mp.observe_property('osd-width', 'native', update)
diff --git a/player/lua/input.lua b/player/lua/input.lua
new file mode 100644
index 0000000000..a73128ec7d
--- /dev/null
+++ b/player/lua/input.lua
@@ -0,0 +1,66 @@
+--[[
+This file is part of mpv.
+
+mpv is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version.
+
+mpv is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
+]]
+
+local utils = require "mp.utils"
+local input = {}
+
+function input.get(t)
+    mp.commandv("script-message-to", "console", "get-input",
+                mp.get_script_name(), utils.format_json({
+                    prompt = t.prompt,
+                    default_text = t.default_text,
+                    cursor_position = t.cursor_position,
+                    id = t.id,
+                }))
+
+    mp.register_script_message("input-event", function (type, text, cursor_position)
+        if t[type] then
+            local suggestions, completion_start_position = t[type](text, cursor_position)
+
+            if type == "complete" and suggestions then
+                mp.commandv("script-message-to", "console", "complete",
+                            utils.format_json(suggestions), completion_start_position)
+            end
+        end
+
+        if type == "closed" then
+            mp.unregister_script_message("input-event")
+        end
+    end)
+
+    return true
+end
+
+function input.terminate()
+    mp.commandv("script-message-to", "console", "disable")
+end
+
+function input.log(message, style)
+    mp.commandv("script-message-to", "console", "log",
+                utils.format_json({ text = message, style = style }))
+end
+
+function input.log_error(message)
+    mp.commandv("script-message-to", "console", "log",
+                 utils.format_json({ text = message, error = true }))
+end
+
+function input.set_log(log)
+    mp.commandv("script-message-to", "console", "set-log", utils.format_json(log))
+end
+
+return input
diff --git a/player/lua/meson.build b/player/lua/meson.build
index 362c87cbb7..1d87938f1a 100644
--- a/player/lua/meson.build
+++ b/player/lua/meson.build
@@ -1,5 +1,6 @@
 lua_files = ['defaults.lua', 'assdraw.lua', 'options.lua', 'osc.lua',
-             'ytdl_hook.lua', 'stats.lua', 'console.lua', 'auto_profiles.lua']
+             'ytdl_hook.lua', 'stats.lua', 'console.lua', 'auto_profiles.lua',
+             'input.lua']
 foreach file: lua_files
     lua_file = custom_target(file,
         input: join_paths(source_root, 'player', 'lua', file),