From 5b69558d06d246c437f141de8fb52f5f817a9241 Mon Sep 17 00:00:00 2001
From: Vitaly Gashkov <vitalygashkov@vk.com>
Date: Tue, 26 Mar 2024 21:42:10 +0500
Subject: [PATCH] feat: add helper filters for hls manifest

---
 lib/dash.js  | 43 +++++++++++--------------------------------
 lib/hls.js   | 10 ++++++++++
 lib/track.js | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 package.json |  2 +-
 4 files changed, 71 insertions(+), 33 deletions(-)
 create mode 100644 lib/track.js

diff --git a/lib/dash.js b/lib/dash.js
index 4d452fc..e3d64d7 100644
--- a/lib/dash.js
+++ b/lib/dash.js
@@ -1,7 +1,13 @@
 'use strict';
 
 const mpdParser = require('mpd-parser');
-const { parseBitrate, parseSize, getWidth, getBestTrack, getQualityLabel } = require('./util');
+const { parseBitrate, parseSize, getQualityLabel } = require('./util');
+const {
+  createResolutionFilter,
+  createVideoQualityFilter,
+  createAudioLanguageFilter,
+  createSubtitleLanguageFilter,
+} = require('./track');
 
 const segmentsDto = (data = []) => {
   const mapSegment = (item) => ({
@@ -115,37 +121,10 @@ const parseManifest = (manifestString, manifestUri) => {
       videos,
       audios,
       subtitles,
-      withResolution({ width, height }) {
-        return videos.filter(
-          (track) =>
-            (!width || track.resolution.width === width) &&
-            (!height || track.resolution.height === height)
-        );
-      },
-      withVideoQuality(quality) {
-        const height = parseInt(quality);
-        const matchHeight = (track) => {
-          if (!height) return false;
-          const trackWidth = track.resolution.width;
-          const targetWidth = getWidth(height);
-          if (!trackWidth || !targetWidth) return false;
-          return trackWidth === targetWidth;
-        };
-        const matches = videos.filter(matchHeight);
-        return matches.length ? matches : [getBestTrack(videos)];
-      },
-      withAudioLanguages(languages) {
-        if (!languages.length) return audios;
-        return audios.filter((track) =>
-          languages.some((language) => track.language.startsWith(language))
-        );
-      },
-      withSubtitleLanguages(languages) {
-        if (!languages.length) return subtitles;
-        return subtitles.filter((track) =>
-          languages.some((language) => track.language.startsWith(language))
-        );
-      },
+      withResolution: createResolutionFilter(videos),
+      withVideoQuality: createVideoQualityFilter(videos),
+      withAudioLanguages: createAudioLanguageFilter(audios),
+      withSubtitleLanguages: createSubtitleLanguageFilter(subtitles),
     },
   };
 
diff --git a/lib/hls.js b/lib/hls.js
index 83b4dec..ec9b9ab 100644
--- a/lib/hls.js
+++ b/lib/hls.js
@@ -2,6 +2,12 @@
 
 const m3u8Parser = require('m3u8-parser');
 const { parseBitrate, getQualityLabel } = require('./util');
+const {
+  createResolutionFilter,
+  createVideoQualityFilter,
+  createAudioLanguageFilter,
+  createSubtitleLanguageFilter,
+} = require('./track');
 
 const parseM3u8 = (manifestString) => {
   const parser = new m3u8Parser.Parser();
@@ -123,6 +129,10 @@ const parseManifest = async (manifestString, manifestUri) => {
       videos,
       audios,
       subtitles,
+      withResolution: createResolutionFilter(videos),
+      withVideoQuality: createVideoQualityFilter(videos),
+      withAudioLanguages: createAudioLanguageFilter(audios),
+      withSubtitleLanguages: createSubtitleLanguageFilter(subtitles),
     },
   };
 
diff --git a/lib/track.js b/lib/track.js
new file mode 100644
index 0000000..2bf6cb4
--- /dev/null
+++ b/lib/track.js
@@ -0,0 +1,49 @@
+const createResolutionFilter = (videos) => {
+  return ({ width, height }) => {
+    return videos.filter(
+      (track) =>
+        (!width || track.resolution.width === width) &&
+        (!height || track.resolution.height === height)
+    );
+  };
+};
+
+const createVideoQualityFilter = (videos) => {
+  return (quality) => {
+    const height = parseInt(quality);
+    const matchHeight = (track) => {
+      if (!height) return false;
+      const trackWidth = track.resolution.width;
+      const targetWidth = getWidth(height);
+      if (!trackWidth || !targetWidth) return false;
+      return trackWidth === targetWidth;
+    };
+    const matches = videos.filter(matchHeight);
+    return matches.length ? matches : [getBestTrack(videos)];
+  };
+};
+
+const createAudioLanguageFilter = (audios) => {
+  return (languages) => {
+    if (!languages.length) return audios;
+    return audios.filter((track) =>
+      languages.some((language) => track.language.startsWith(language))
+    );
+  };
+};
+
+const createSubtitleLanguageFilter = (subtitles) => {
+  return (languages) => {
+    if (!languages.length) return subtitles;
+    return subtitles.filter((track) =>
+      languages.some((language) => track.language.startsWith(language))
+    );
+  };
+};
+
+module.exports = {
+  createResolutionFilter,
+  createVideoQualityFilter,
+  createAudioLanguageFilter,
+  createSubtitleLanguageFilter,
+};
diff --git a/package.json b/package.json
index 7b5cd49..6c170d3 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "dasha",
-  "version": "3.0.0.alpha.4",
+  "version": "3.0.0.alpha.5",
   "author": "Vitaly Gashkov <vitalygashkov@vk.com>",
   "description": "Parser for MPEG-DASH & HLS manifests",
   "license": "AGPL-3.0",