move application-aware utility functions to separate module

5 files changed, 460 insertions, 409 deletions

diff --git a/main.lua b/main.lua
index 71abee8..cadece7 100644
--- a/main.lua
+++ b/main.lua
@@ -4,6 +4,7 @@ local cacher = require('cacher')
 local config = require('config')
 local input = require('input')
 local rt = require('rt')
+local rx = require('rx')
 local util = require('util')
 local _catalogue = require('catalogue')
 local _downloader = require('downloader')
@@ -75,6 +76,7 @@ local ctx = {
 	xc = xc,
 }
 rt.init(state, osd, ctx)
+rx.init(state, osd, ctx)
 
 mp.observe_property('mouse-pos', 'native', function(_, mpos)
 	input.update_mpos(mpos)
diff --git a/osd.lua b/osd.lua
index 87da3ab..2a05018 100644
--- a/osd.lua
+++ b/osd.lua
@@ -257,7 +257,7 @@ function mt:option_text(opt, info)
 		str = col .. '[' .. str .. ']'
 	end
 
-	if opt.programme and opt.type == 'programme' and opt.active then
+	if opt.programme and opt.active then
 		str = str .. ' ' .. self:draw_progress_bar(
 			opt.programme, colour.progress_bar_fg_active,
 			colour.progress_bar_bg_active)
@@ -268,9 +268,9 @@ function mt:option_text(opt, info)
 		str = str .. colour.info .. ' (' .. asscape(opt_info) .. ')'
 	end
 
-	if opt.programme and opt.type ~= 'programme' then
+	if opt.active_programme then
 		str = str .. ' ' .. self:draw_progress_bar(
-			opt.programme,
+			opt.active_programme,
 			info.selected and colour.progress_bar_fg_active or
 				colour.progress_bar_fg,
 			info.selected and colour.progress_bar_bg_active or
diff --git a/rt.lua b/rt.lua
index 77e6ff7..1cdf777 100644
--- a/rt.lua
+++ b/rt.lua
@@ -2,6 +2,7 @@
 
 local config = require('config')
 local input = require('input')
+local rx = require('rx')
 local util = require('util')
 
 local rt = {}
@@ -30,68 +31,10 @@ local function cache_miss_status_msg(str)
 end
 
 local function series_children(series)
-	local info = ctx.xc:with_opts('get_series_info', series.series_id,
-		cache_miss_status_msg('Loading series info...'))
-	if not info or not info.seasons then
-		return {}
-	end
-
-	local seasons = {}
-	for _, season in pairs(info.seasons) do
-		local episodes = {}
-		local season_num = tostring(season.season_number)
-		if info.episodes and info.episodes[season_num] then
-			for i, episode in pairs(info.episodes[season_num]) do
-				local epinfo = episode.info or {}
-				local t = {
-					name = util.strip(episode.title),
-					type = 'stream',
-					stream_type = 'series',
-					id = series.section .. ':stream:' ..
-						episode.id,
-					stream_id = episode.id,
-					img_url = util.strip_ne(
-						epinfo.movie_image),
-				}
-				t.info_data = {
-					name = t.name,
-					cover = t.img_url,
-					description = epinfo.plot,
-					releasedate = epinfo.releasedate,
-					duration = epinfo.duration,
-					video = epinfo.video,
-					audio = epinfo.audio,
-				}
-				episodes[#episodes+1] = t
-			end
-		end
-
-		local count = tostring(#episodes)
-		local tmp = util.strip_ne(season.episode_count)
-		if tmp then
-			count = count .. '/' .. tmp
-		end
-		local t = {
-			type = 'group',
-			group_type = 'season',
-			id = series.id .. ':season:' .. season.id,
-			children = episodes,
-			name = util.strip(season.name),
-			info = count,
-			img_url = util.strip_ne(season.cover_big) or
-				util.strip_ne(season.cover),
-		}
-		t.info_data = {
-			name = t.name,
-			cover = t.img_url,
-			description = season.overview,
-			releasedate = season.air_date,
-			num_episodes = count,
-		}
-		seasons[#seasons+1] = t
-	end
-
-	return seasons
+	return rx.series_children(
+		series,
+		ctx.xc:with_opts('get_series_info', series.series_id,
+			cache_miss_status_msg('Loading series info...')))
 end
 
 local function catalogue_add_section(sect, cats, elems)
@@ -278,7 +221,7 @@ function rt.cursor_wheel_page_down()
 		{keep_offset = true})
 end
 
-local function cursor_to_object(id)
+local function cursor_to_id(id)
 	for i, v in ipairs(state:menu().options) do
 		if v.id == id then
 			rt.set_cursor(i, {centre = true})
@@ -361,93 +304,9 @@ function rt.move_option_wheel_page_down()
 		{keep_offset = true})
 end
 
-local function sort_options(options)
-	local scores = {}
-	for _, v in ipairs(options) do
-		local score = 0
-		if v.missing then
-			score = score - 4
-		end
-		if state:favourited(v.id) then
-			score = score + 2
-		end
-		if v.type == 'group' and v.group_type ~= 'series' then
-			score = score + 1
-		end
-		scores[v] = score
-	end
-
-	table.sort(options, function(a, b)
-		local sa = scores[a]
-		local sb = scores[b]
-		if sa ~= sb then
-			return sa > sb
-		else
-			return a.name < b.name
-		end
-	end)
-end
-
-local menu_option_mt = {
-	__index = function(t, k)
-		local v = t._v
-
-		if k == 'info' then
-			if v.type == 'group' and not v.hide_count then
-				local c = ctx.catalogue:group_count(v)
-				local ret = c and tostring(c) or ''
-				if not v.count_f then
-					rawset(t, 'info', ret)
-				end
-				return ret
-			elseif v.epg_channel_id then
-				local time = osd.redraw_time
-				if t._exp and time < t._exp then
-					return t._info
-				end
-
-				local prog = ctx.epg:scheduled_programme(
-					v.epg_channel_id, time)
-				local ret = prog and prog.title or ''
-				local exp = prog and prog.stop
-				rawset(t, 'programme', prog)
-
-				if not prog then
-					prog = ctx.epg:next_programme(
-						v.epg_channel_id, time)
-					exp = prog and prog.start
-				end
-
-				rawset(t, exp and '_info' or 'info', ret)
-				rawset(t, '_exp', exp)
-				return ret
-			end
-		end
-
-		return v[k]
-	end,
-}
-
-local function group_menu_options(group)
-	local options = {}
-	for i, v in ipairs(ctx.catalogue:group_children(group)) do
-		local t = setmetatable({_v = v}, menu_option_mt)
-
-		if group.id == 'favourites' then
-			local path = ctx.catalogue:path_from_root(v)
-			if path then
-				t.path = path
-			end
-		end
-
-		options[i] = t
-	end
-	return options
-end
-
 function rt.push_group_menu(group)
 	state:push_menu({
-		options = group_menu_options(group),
+		options = rx.menu_options_group(group),
 		title = group.name,
 		type = 'group',
 		group_id = group.id,
@@ -455,9 +314,7 @@ function rt.push_group_menu(group)
 end
 
 -- refresh options when navigating up the stack to a previous favourites menu.
--- existing menu options are never removed, even if unfavourited. the new order
--- is always respected, while still preserving the relative order of existing
--- options when possible.
+-- existing menu options are never removed, even if unfavourited.
 local function refresh_favourites_menu()
 	local menu = state:menu()
 	local opt = menu.options[menu.cursor]
@@ -466,41 +323,16 @@ local function refresh_favourites_menu()
 		menu:set_sort(false)
 	end
 
-	local options = group_menu_options(ctx.catalogue:get(menu.group_id))
-	local pos = {}
-	for i, v in ipairs(options) do
-		pos[v.id] = i
-	end
-
-	local res = {}
-	local seen = {}
-	local function append(v)
-		if not seen[v.id] then
-			res[#res+1] = v
-			seen[v.id] = true
-		end
-	end
-
-	local ind = 1
-	for _, v in ipairs(menu.options) do
-		if pos[v.id] then
-			while ind <= pos[v.id] do
-				append(options[ind])
-				ind = ind + 1
-			end
-		end
-		append(v)
-	end
-	for i = ind, #options do
-		append(options[i])
-	end
-	menu.options = res
+	menu.options = util.stable_kmerge(
+		menu.options,
+		rx.menu_options_group(ctx.catalogue:get(menu.group_id)),
+		'id')
 
 	if sorted then
-		menu:set_sort(true, sort_options)
+		menu:set_sort(true, rx.sort_menu_options)
 	end
 	if opt then
-		cursor_to_object(opt.id)
+		cursor_to_id(opt.id)
 	end
 end
 
@@ -584,10 +416,10 @@ function rt.goto_option()
 	end
 
 	for i = 1, #opt.path do
-		cursor_to_object(opt.path[i].id)
+		cursor_to_id(opt.path[i].id)
 		rt.push_group_menu(opt.path[i])
 	end
-	cursor_to_object(opt.id)
+	cursor_to_id(opt.id)
 
 	osd:dirty()
 end
@@ -602,231 +434,82 @@ function rt.goto_playing()
 
 	state.depth = 1
 	for i = #path, 1, -1 do
-		cursor_to_object(path[i].id)
+		cursor_to_id(path[i].id)
 		rt.push_group_menu(path[i])
 	end
-	cursor_to_object(id)
+	cursor_to_id(id)
 
 	osd:dirty()
 end
 
-local function open_epg_programme(prog, img_url)
-	local options = {
-		{name = 'Title: ' .. prog.title},
-		{name = 'Start: ' .. os.date('%a %d %b %H:%M', prog.start)},
-		{name = 'Stop: ' .. os.date('%a %d %b %H:%M', prog.stop)},
-	}
-
-	if prog.desc then
-		options[#options+1] = {name = ''}
-		for _, v in ipairs(util.wrap(prog.desc, 80)) do
-			options[#options+1] = {name = v}
-		end
+local function open_option_programme_info(opt, img_url)
+	local prog = opt.programme
+	local options = rx.menu_options_programme_info(prog)
+	if not options then
+		return
 	end
 
-	local menu = state:push_menu({
+	state:push_menu({
 		options = options,
-		title = 'Programme: ' .. prog.title,
-		type = 'epg',
+		title = 'Programme Info: ' .. prog.title,
+		type = 'info',
+		img_url = img_url,
 	})
-	if img_url then
-		menu.img_url = img_url
-	end
 	osd:dirty()
 end
 
-local epg_programme_mt = {
-	__index = function(t, k)
-		if k == 'active' then
-			local time = osd.redraw_time
-			if t._exp and time < t._exp then
-				return t._active
-			end
-
-			local v = t.programme
-			local ret = time >= v.start and time < v.stop
-			local exp = time < v.start and v.start or
-				ret and v.stop or nil
-			rawset(t, exp and '_active' or 'active', ret)
-			rawset(t, '_exp', exp)
-			return ret
-		end
-	end,
-}
-
-local function open_option_epg(opt)
+local function open_option_channel_epg(opt)
 	local ch = opt.epg_channel_id:lower()
-	local progs = ctx.epg:channel_programmes(ch)
-	if not progs then
+	local options, idx = rx.menu_options_channel_epg(ch)
+	if not options then
 		return
 	end
 
-	local options = {}
-	local idx
-	local time = os.time()
-	for i, v in ipairs(progs) do
-		local prog = {
-			name = os.date('%a %d %b %H:%M', v.start) .. ' ' ..
-				os.date('%H:%M', v.stop) .. ' ' .. v.title,
-			type = 'programme',
-			info = v.desc,
-			programme = v,
-		}
-
-		if not idx and time < v.stop then
-			idx = i
-		end
-
-		options[i] = setmetatable(prog, epg_programme_mt)
-	end
-	idx = idx or #options
-
-	local menu = state:push_menu({
+	state:push_menu({
 		options = options,
 		title = 'EPG: ' .. opt.name .. ' (' .. ch .. ')',
 		type = 'epg',
+		img_url = opt.img_url,
 	})
-	if opt.img_url then
-		menu.img_url = opt.img_url
-	end
 	rt.set_cursor(idx, {centre = true})
 	osd:dirty()
 end
 
-local function add_info_field(dst, k, v, fmt)
-	local str = util.strip_ne(v)
-	if not str then
-		return
-	end
-	if fmt then
-		str = string.format(fmt, str)
-	end
-	if k then
-		str = k .. ': ' .. str
-	end
-
-	-- continuation lines are 4 chars shorter and indented with 2 em spaces
-	for i, v in ipairs(util.wrap(str, 80, 76)) do
-		if i > 1 then
-			v = '\xe2\x80\x83\xe2\x80\x83' .. v
-		end
-		dst[#dst+1] = {name = v}
-	end
-end
-
-local function add_info_set(options, set)
-	if #set > 0 then
-		options[#options+1] = {name = ''}
-		for _, v in ipairs(set) do
-			options[#options+1] = v
-		end
-	end
-end
-
-local function open_option_title_info(title, info)
-	if not info or not info.info then
+local function open_option_entry_info(title, info)
+	local options, img = rx.menu_options_entry_info(info)
+	if not options then
 		return
 	end
-	local info = info.info
-
-	local options = {}
-	add_info_field(options, nil, info.name)
-	add_info_field(options, 'Directed by', info.director)
-	add_info_field(options, 'Starring', info.cast)
-
-	local desc = util.strip_ne(info.description) or
-		util.strip_ne(info.plot)
-	if desc then
-		options[#options+1] = {name = ''}
-		for _, v in ipairs(util.wrap(desc, 80)) do
-			options[#options+1] = {name = v}
-		end
-	end
 
-	local set = {}
-	add_info_field(set, 'Genre', info.genre)
-	local date = util.strip_ne(info.releasedate) or
-		util.strip_ne(info.releaseDate)
-	if date then
-		local y, m, d = date:match('(%d+)-(%d+)-(%d+)')
-		if y then
-			local dt = {year = y, month = m, day = d}
-			add_info_field(set, 'Release date',
-				os.date('%d %B %Y', os.time(dt)))
-		end
-	end
-	add_info_field(set, 'Episode count', info.num_episodes)
-	add_info_field(set, 'Running time', info.duration)
-	add_info_set(options, set)
-
-	local set = {}
-	if info.video then
-		local w = util.strip_ne(info.video.width)
-		local h = util.strip_ne(info.video.height)
-		if w and h then
-			local res = w .. 'x' .. h
-			local ar = util.strip_ne(
-				info.video.display_aspect_ratio)
-			if ar then
-				res = res .. ' (' .. ar .. ')'
-			end
-			add_info_field(set, 'Resolution', res)
-		end
-		add_info_field(set, 'Video codec', info.video.codec_long_name)
-	end
-	if info.audio then
-		add_info_field(set, 'Audio codec', info.audio.codec_long_name)
-	end
-	if info.bitrate ~= 0 then
-		add_info_field(set, 'Bitrate', info.bitrate, '%s Kbps')
-	end
-	add_info_set(options, set)
-
-	local ytid = util.strip_ne(info.youtube_trailer)
-	if ytid then
-		local url = 'https://youtu.be/' .. ytid
-		add_info_set(options, {{
-			name = 'Trailer: ' .. url,
-			type = 'stream',
-			id = 'youtube:' .. ytid,
-			stream_url = url,
-		}})
-	end
-
-	local m = {
+	state:push_menu({
 		options = options,
 		title = title,
 		type = 'info',
-	}
-	local img = util.strip_ne(info.cover_big) or util.strip_ne(info.cover)
-	if img then
-		m.img_url = img
-	end
-
-	state:push_menu(m)
+		img_url = img,
+	})
 	osd:dirty()
 end
 
 local function open_option_movie_info(opt)
 	local info = ctx.xc:with_opts('get_vod_info', opt.stream_id,
 		cache_miss_status_msg('Loading movie info...'))
-	open_option_title_info('Movie Info: ' .. opt.name, info)
+	open_option_entry_info('Movie Info: ' .. opt.name, info)
 end
 
 local function open_option_series_info(opt)
 	local info = ctx.xc:with_opts('get_series_info', opt.series_id,
 		cache_miss_status_msg('Loading series info...'))
-	open_option_title_info('Series Info: ' .. opt.name, info)
+	open_option_entry_info('Series Info: ' .. opt.name, info)
 end
 
 local function open_option_season_info(opt)
-	open_option_title_info(
+	open_option_entry_info(
 		'Season Info: ' .. opt.name,
 		{info = opt.info_data})
 end
 
 local function open_option_episode_info(opt)
-	open_option_title_info(
+	open_option_entry_info(
 		'Episode Info: ' .. opt.name,
 		{info = opt.info_data})
 end
@@ -838,10 +521,10 @@ function rt.open_option_info(opt)
 		return
 	end
 
-	if menu.type == 'epg' and opt.programme then
-		open_epg_programme(opt.programme, menu.img_url)
+	if opt.programme then
+		open_option_programme_info(opt, menu.img_url)
 	elseif opt.epg_channel_id then
-		open_option_epg(opt)
+		open_option_channel_epg(opt)
 	elseif opt.group_type == 'series' then
 		open_option_series_info(opt)
 	elseif opt.group_type == 'season' then
@@ -853,48 +536,6 @@ function rt.open_option_info(opt)
 	end
 end
 
-local function search_menu_options_build(options, t, path)
-	for _, v in ipairs(options) do
-		v.path = path
-
-		if v.type == 'group' and v.group_type ~= 'series' then
-			t.categories[#t.categories+1] = v
-		else
-			t.elements[#t.elements+1] = v
-		end
-
-		-- contents of lazy-loaded groups should not be searchable
-		if v.type == 'group' and v.children then
-			local path = util.copy_table(path)
-			path[#path+1] = v
-			search_menu_options_build(
-				group_menu_options(v), t, path)
-		end
-	end
-end
-
-local function search_menu_options(options)
-	local t = {categories = {}, elements = {}}
-
-	local opts = {}
-	for i, v in ipairs(options) do
-		-- menu options may contain dynamic data that is updated on
-		-- redraw. using a proxy table instead of copying allows a
-		-- single update to target both the source and search menus.
-		opts[i] = setmetatable({}, {__index = v})
-	end
-
-	-- empty table is needed to shadow existing path from proxied table
-	search_menu_options_build(opts, t, {})
-
-	-- display categories first
-	local ret = t.categories
-	for _, v in ipairs(t.elements) do
-		ret[#ret+1] = v
-	end
-	return ret
-end
-
 function rt.search_input_char(ev)
 	if ev.event ~= 'down' and ev.event ~= 'repeat' then
 		return
@@ -981,7 +622,7 @@ function rt.start_search()
 		state:push_menu({
 			title = title,
 			type = 'search',
-			options = search_menu_options(menu.options),
+			options = rx.menu_options_search(menu.options),
 			search_active = true,
 		})
 	end
@@ -1023,7 +664,7 @@ function rt.toggle_menu_sort()
 		return
 	end
 
-	menu:set_sort(not menu.sorted, sort_options)
+	menu:set_sort(not menu.sorted, rx.sort_menu_options)
 	osd:dirty()
 end
 
diff --git a/rx.lua b/rx.lua
new file mode 100644
index 0000000..007ca13
--- /dev/null
+++ b/rx.lua
@@ -0,0 +1,374 @@
+-- Copyright 2025 David Vazgenovich Shakaryan
+
+local util = require('util')
+
+local rx = {}
+
+local state
+local osd
+local ctx
+
+function rx.init(_state, _osd, _ctx)
+	state = _state
+	osd = _osd
+	ctx = _ctx
+end
+
+function rx.series_children(series, info)
+	if not info or not info.seasons then
+		return {}
+	end
+
+	local seasons = {}
+	for _, season in pairs(info.seasons) do
+		local episodes = {}
+		local season_num = tostring(season.season_number)
+		if info.episodes and info.episodes[season_num] then
+			for i, episode in pairs(info.episodes[season_num]) do
+				local epinfo = episode.info or {}
+				local t = {
+					name = util.strip(episode.title),
+					type = 'stream',
+					stream_type = 'series',
+					id = series.section .. ':stream:' ..
+						episode.id,
+					stream_id = episode.id,
+					img_url = util.strip_ne(
+						epinfo.movie_image),
+				}
+				t.info_data = {
+					name = t.name,
+					cover = t.img_url,
+					description = epinfo.plot,
+					releasedate = epinfo.releasedate,
+					duration = epinfo.duration,
+					video = epinfo.video,
+					audio = epinfo.audio,
+				}
+				episodes[#episodes+1] = t
+			end
+		end
+
+		local count = tostring(#episodes)
+		local tmp = util.strip_ne(season.episode_count)
+		if tmp then
+			count = count .. '/' .. tmp
+		end
+		local t = {
+			type = 'group',
+			group_type = 'season',
+			id = series.id .. ':season:' .. season.id,
+			children = episodes,
+			name = util.strip(season.name),
+			info = count,
+			img_url = util.strip_ne(season.cover_big) or
+				util.strip_ne(season.cover),
+		}
+		t.info_data = {
+			name = t.name,
+			cover = t.img_url,
+			description = season.overview,
+			releasedate = season.air_date,
+			num_episodes = count,
+		}
+		seasons[#seasons+1] = t
+	end
+
+	return seasons
+end
+
+local entry_mt = {
+	__index = function(t, k)
+		local v = t._v
+
+		if k == 'info' then
+			if v.type == 'group' and not v.hide_count then
+				local c = ctx.catalogue:group_count(v)
+				local ret = c and tostring(c) or ''
+				if not v.count_f then
+					rawset(t, 'info', ret)
+				end
+				return ret
+			elseif v.epg_channel_id then
+				local time = osd.redraw_time
+				if t._exp and time < t._exp then
+					return t._info
+				end
+
+				local prog = ctx.epg:scheduled_programme(
+					v.epg_channel_id, time)
+				local ret = prog and prog.title or ''
+				local exp = prog and prog.stop
+				rawset(t, 'active_programme', prog)
+
+				if not prog then
+					prog = ctx.epg:next_programme(
+						v.epg_channel_id, time)
+					exp = prog and prog.start
+				end
+
+				rawset(t, exp and '_info' or 'info', ret)
+				rawset(t, '_exp', exp)
+				return ret
+			end
+		end
+
+		return v[k]
+	end,
+}
+
+function rx.menu_options_group(group)
+	local options = {}
+	for i, v in ipairs(ctx.catalogue:group_children(group)) do
+		local t = setmetatable({_v = v}, entry_mt)
+
+		if group.id == 'favourites' then
+			local path = ctx.catalogue:path_from_root(v)
+			if path then
+				t.path = path
+			end
+		end
+
+		options[i] = t
+	end
+	return options
+end
+
+local function add_info_field(dst, k, v, fmt)
+	local str = util.strip_ne(v)
+	if not str then
+		return
+	end
+	if fmt then
+		str = string.format(fmt, str)
+	end
+	if k then
+		str = k .. ': ' .. str
+	end
+
+	-- continuation lines are 4 chars shorter and indented with 2 em spaces
+	for i, v in ipairs(util.wrap(str, 80, 76)) do
+		if i > 1 then
+			v = '\xe2\x80\x83\xe2\x80\x83' .. v
+		end
+		dst[#dst+1] = {name = v}
+	end
+end
+
+local function add_info_set(options, set)
+	if #set > 0 then
+		options[#options+1] = {name = ''}
+		for _, v in ipairs(set) do
+			options[#options+1] = v
+		end
+	end
+end
+
+function rx.menu_options_entry_info(info)
+	if not info or not info.info then
+		return
+	end
+	local info = info.info
+
+	local options = {}
+	add_info_field(options, nil, info.name)
+	add_info_field(options, 'Directed by', info.director)
+	add_info_field(options, 'Starring', info.cast)
+
+	local desc = util.strip_ne(info.description) or
+		util.strip_ne(info.plot)
+	if desc then
+		options[#options+1] = {name = ''}
+		for _, v in ipairs(util.wrap(desc, 80)) do
+			options[#options+1] = {name = v}
+		end
+	end
+
+	local set = {}
+	add_info_field(set, 'Genre', info.genre)
+	local date = util.strip_ne(info.releasedate) or
+		util.strip_ne(info.releaseDate)
+	if date then
+		local y, m, d = date:match('(%d+)-(%d+)-(%d+)')
+		if y then
+			local dt = {year = y, month = m, day = d}
+			add_info_field(set, 'Release date',
+				os.date('%d %B %Y', os.time(dt)))
+		end
+	end
+	add_info_field(set, 'Episode count', info.num_episodes)
+	add_info_field(set, 'Running time', info.duration)
+	add_info_set(options, set)
+
+	local set = {}
+	if info.video then
+		local w = util.strip_ne(info.video.width)
+		local h = util.strip_ne(info.video.height)
+		if w and h then
+			local res = w .. 'x' .. h
+			local ar = util.strip_ne(
+				info.video.display_aspect_ratio)
+			if ar then
+				res = res .. ' (' .. ar .. ')'
+			end
+			add_info_field(set, 'Resolution', res)
+		end
+		add_info_field(set, 'Video codec', info.video.codec_long_name)
+	end
+	if info.audio then
+		add_info_field(set, 'Audio codec', info.audio.codec_long_name)
+	end
+	if info.bitrate ~= 0 then
+		add_info_field(set, 'Bitrate', info.bitrate, '%s Kbps')
+	end
+	add_info_set(options, set)
+
+	local ytid = util.strip_ne(info.youtube_trailer)
+	if ytid then
+		local url = 'https://youtu.be/' .. ytid
+		add_info_set(options, {{
+			name = 'Trailer: ' .. url,
+			type = 'stream',
+			id = 'youtube:' .. ytid,
+			stream_url = url,
+		}})
+	end
+
+	local img = util.strip_ne(info.cover_big) or util.strip_ne(info.cover)
+	return options, img
+end
+
+local programme_mt = {
+	__index = function(t, k)
+		if k == 'active' then
+			local time = osd.redraw_time
+			if t._exp and time < t._exp then
+				return t._active
+			end
+
+			local v = t.programme
+			local ret = time >= v.start and time < v.stop
+			local exp = time < v.start and v.start or
+				ret and v.stop or nil
+			rawset(t, exp and '_active' or 'active', ret)
+			rawset(t, '_exp', exp)
+			return ret
+		end
+	end,
+}
+
+function rx.menu_options_channel_epg(ch)
+	local progs = ctx.epg:channel_programmes(ch)
+	if not progs then
+		return
+	end
+
+	local options = {}
+	local idx
+	local time = os.time()
+	for i, v in ipairs(progs) do
+		local prog = {
+			name = os.date('%a %d %b %H:%M', v.start) .. ' ' ..
+				os.date('%H:%M', v.stop) .. ' ' .. v.title,
+			type = 'programme',
+			info = v.desc,
+			programme = v,
+		}
+
+		if not idx and time < v.stop then
+			idx = i
+		end
+
+		options[i] = setmetatable(prog, programme_mt)
+	end
+
+	return options, idx or #options
+end
+
+function rx.menu_options_programme_info(prog)
+	local options = {
+		{name = 'Title: ' .. prog.title},
+		{name = 'Start: ' .. os.date('%a %d %b %H:%M', prog.start)},
+		{name = 'Stop: ' .. os.date('%a %d %b %H:%M', prog.stop)},
+	}
+
+	if prog.desc then
+		options[#options+1] = {name = ''}
+		for _, v in ipairs(util.wrap(prog.desc, 80)) do
+			options[#options+1] = {name = v}
+		end
+	end
+
+	return options
+end
+
+local function menu_options_search_build(options, t, path)
+	for _, v in ipairs(options) do
+		v.path = path
+
+		if v.type == 'group' and v.group_type ~= 'series' then
+			t.categories[#t.categories+1] = v
+		else
+			t.elements[#t.elements+1] = v
+		end
+
+		-- contents of lazy-loaded groups should not be searchable
+		if v.type == 'group' and v.children then
+			local path = util.copy_table(path)
+			path[#path+1] = v
+			menu_options_search_build(
+				rx.menu_options_group(v), t, path)
+		end
+	end
+end
+
+function rx.menu_options_search(opts)
+	local t = {categories = {}, elements = {}}
+
+	local options = {}
+	for i, v in ipairs(opts) do
+		-- menu options may contain dynamic data that is updated on
+		-- redraw. using a proxy table instead of copying allows a
+		-- single update to target both the source and search menus.
+		options[i] = setmetatable({}, {__index = v})
+	end
+
+	-- empty table is needed to shadow existing path from proxied table
+	menu_options_search_build(options, t, {})
+
+	-- display categories first
+	options = t.categories
+	for _, v in ipairs(t.elements) do
+		options[#options+1] = v
+	end
+	return options
+end
+
+function rx.sort_menu_options(opts)
+	local scores = {}
+	for _, v in ipairs(opts) do
+		local score = 0
+		if v.missing then
+			score = score - 4
+		end
+		if state:favourited(v.id) then
+			score = score + 2
+		end
+		if v.type == 'group' and v.group_type ~= 'series' then
+			score = score + 1
+		end
+		scores[v] = score
+	end
+
+	table.sort(opts, function(a, b)
+		local sa = scores[a]
+		local sb = scores[b]
+		if sa ~= sb then
+			return sa > sb
+		else
+			return a.name < b.name
+		end
+	end)
+end
+
+return rx
diff --git a/util.lua b/util.lua
index 99f8fe8..04e1bf6 100644
--- a/util.lua
+++ b/util.lua
@@ -91,4 +91,38 @@ function util.write_json_file(path, data)
 	f:close()
 end
 
+-- merges tables `t' and `u', using key `k' for identity. the order from `u' is
+-- always respected, preserving the relative order from `t' when possible.
+function util.stable_kmerge(t, u, k)
+	local pos = {}
+	for i, v in ipairs(u) do
+		pos[v[k]] = i
+	end
+
+	local res = {}
+	local seen = {}
+	local function append(v)
+		if not seen[v[k]] then
+			res[#res+1] = v
+			seen[v[k]] = true
+		end
+	end
+
+	local ind = 1
+	for _, v in ipairs(t) do
+		if pos[v[k]] then
+			while ind <= pos[v[k]] do
+				append(u[ind])
+				ind = ind + 1
+			end
+		end
+		append(v)
+	end
+	for i = ind, #u do
+		append(u[i])
+	end
+
+	return res
+end
+
 return util