medias 0.3.3

//! YouTube internal "InnerTube" API (youtubei/v1) for data the public Data API
//! v3 does not expose: the personalized recommendation feed (browse) and
//! direct stream URLs (player).
//!
//! Client contexts and response paths are ported from the Kodi YouTube plugin
//! (plugin.video.youtube): `tv` + `tv_shelf_horizontal` for browse, and the
//! `ios_testsuite_params` / `android_testsuite_params` clients for player,
//! which return plain (un-ciphered, ratebypass) URLs. InnerTube is undocumented
//! and drifts between client versions; parsers are tolerant and callers fall
//! back on failure.

use std::collections::HashSet;
use std::time::Duration;

use serde_json::{Value, json};

use crate::youtube::model::{Thumbs, Video};

#[cfg(feature = "youtube-tv")]
const BROWSE_URL: &str = "https://www.youtube.com/youtubei/v1/browse?prettyPrint=false";
const PLAYER_URL: &str = "https://www.youtube.com/youtubei/v1/player?prettyPrint=false";
// TVHTML5 ("tv") client, mirroring the Kodi plugin's config.
#[cfg(feature = "youtube-tv")]
const TV_CLIENT_NAME: &str = "TVHTML5";
#[cfg(feature = "youtube-tv")]
const TV_CLIENT_VERSION: &str = "7.20250923.13.00";
#[cfg(feature = "youtube-tv")]
const TV_CLIENT_ID: &str = "7";
#[cfg(feature = "youtube-tv")]
const TV_USER_AGENT: &str = "Mozilla/5.0 (ChromiumStylePlatform) Cobalt/25.lts.30.1034943-gold \
    (unlike Gecko) Unknown_TV_Unknown_0/Unknown (Unknown, Unknown)";
#[cfg(feature = "youtube-tv")]
const RECOMMENDATIONS_BROWSE_ID: &str = "FEwhat_to_watch";
// Player params selecting the testsuite variant (Kodi `_PLAYER_PARAMS['testsuite']`).
const TESTSUITE_PARAMS: &str = "2AMB";

fn agent() -> ureq::Agent {
    ureq::Agent::config_builder()
        .http_status_as_error(false)
        .timeout_global(Some(Duration::from_secs(20)))
        .build()
        .into()
}

/// POST a JSON body; returns (HTTP status, response text).
fn post_json(url: &str, body: &Value, headers: &[(&str, &str)]) -> Result<(u16, String), String> {
    let payload = serde_json::to_vec(body).map_err(|e| e.to_string())?;
    let mut request = agent().post(url).header("Content-Type", "application/json");
    for (name, value) in headers {
        request = request.header(*name, *value);
    }
    let mut resp = request.send(&payload).map_err(|e| format!("innertube request: {e}"))?;
    let status = resp.status().as_u16();
    let text = resp.body_mut().read_to_string().map_err(|e| format!("innertube read: {e}"))?;
    Ok((status, text))
}

// ---- recommendations (browse) ----------------------------------------------

/// The signed-in account's personalized recommendation feed. An empty vector
/// means the feed was absent (not an error) so the caller can fall back.
#[cfg(feature = "youtube-tv")]
pub fn recommendations(access_token: &str) -> Result<Vec<Video>, String> {
    let body = json!({
        "context": {
            "client": {
                "clientName": TV_CLIENT_NAME,
                "clientVersion": TV_CLIENT_VERSION,
                "deviceMake": "Samsung",
                "deviceModel": "SmartTV",
                "osName": "Tizen",
                "osVersion": "4.0.0.2",
                "platform": "TV",
                "hl": "en",
                "gl": "US",
                "utcOffsetMinutes": 0,
            },
            "request": {"internalExperimentFlags": [], "useSsl": true},
            "user": {"lockedSafetyMode": false},
        },
        "contentCheckOk": true,
        "racyCheckOk": true,
        "browseId": RECOMMENDATIONS_BROWSE_ID,
    });
    let auth = format!("Bearer {access_token}");
    let (status, text) = post_json(
        BROWSE_URL,
        &body,
        &[
            ("Authorization", &auth),
            ("User-Agent", TV_USER_AGENT),
            ("X-YouTube-Client-Name", TV_CLIENT_ID),
            ("X-YouTube-Client-Version", TV_CLIENT_VERSION),
        ],
    )?;
    // MEDIAS_YT_DEBUG dumps the raw browse response (and HTTP status) so an empty
    // or differently-shaped feed can be diagnosed off-device.
    if std::env::var("MEDIAS_YT_DEBUG").is_ok_and(|v| !v.is_empty())
        && let Some(home) = std::env::var_os("HOME")
    {
        let path = std::path::Path::new(&home).join("medias").join("innertube-browse.json");
        let _ = std::fs::write(&path, &text);
        eprintln!("innertube: HTTP {status}, {} bytes -> {}", text.len(), path.display());
    }
    let root: Value = serde_json::from_str(&text).map_err(|e| format!("innertube json: {e}"))?;
    Ok(parse_recommendations(&root))
}

/// Extract videos from a TVHTML5 browse response (`tv_shelf_horizontal`): walk
/// each shelf in the section list and collect its tiles, de-duplicating by id.
#[cfg(feature = "youtube-tv")]
fn parse_recommendations(root: &Value) -> Vec<Video> {
    let mut videos = Vec::new();
    let mut seen = HashSet::new();
    let Some(shelves) = root
        .pointer("/contents/tvBrowseRenderer/content/tvSurfaceContentRenderer/content/sectionListRenderer/contents")
        .and_then(Value::as_array)
    else {
        return videos;
    };
    for shelf in shelves {
        let items = shelf
            .pointer("/shelfRenderer/content/horizontalListRenderer/items")
            .or_else(|| shelf.pointer("/shelfRenderer/content/verticalListRenderer/items"))
            .and_then(Value::as_array);
        let Some(items) = items else { continue };
        for item in items {
            if let Some(v) = parse_tile(item)
                && seen.insert(v.id.clone())
            {
                videos.push(v);
            }
        }
    }
    videos
}

#[cfg(feature = "youtube-tv")]
fn parse_tile(item: &Value) -> Option<Video> {
    let tile = item.get("tileRenderer")?;
    let id = tile.pointer("/onSelectCommand/watchEndpoint/videoId")?.as_str()?.to_string();
    if id.is_empty() {
        return None;
    }
    let meta = tile.pointer("/metadata/tileMetadataRenderer");
    let title = meta.and_then(|m| text_of(m.get("title"))).unwrap_or_default();
    let channel = meta.and_then(channel_from_lines).unwrap_or_default();
    let thumbs = thumbs_from(tile.pointer("/header/tileHeaderRenderer/thumbnail/thumbnails"));
    Some(Video { id, title, channel, duration: 0, thumbs })
}

/// Channel name from the first metadata line that carries text.
#[cfg(feature = "youtube-tv")]
fn channel_from_lines(meta: &Value) -> Option<String> {
    let lines = meta.get("lines")?.as_array()?;
    lines.iter().find_map(|line| {
        let items = line.pointer("/lineRenderer/items")?.as_array()?;
        items
            .iter()
            .find_map(|it| text_of(it.pointer("/lineItemRenderer/text")).filter(|t| !t.is_empty()))
    })
}

/// A YouTube text node: either `simpleText` or concatenated `runs[].text`.
fn text_of(node: Option<&Value>) -> Option<String> {
    let node = node?;
    if let Some(s) = node.get("simpleText").and_then(Value::as_str) {
        return Some(s.to_string());
    }
    let runs = node.get("runs")?.as_array()?;
    let text: String = runs.iter().filter_map(|r| r.get("text").and_then(Value::as_str)).collect();
    (!text.is_empty()).then_some(text)
}

/// Fill the Thumbs sizes from the thumbnail list (smallest/median/largest).
fn thumbs_from(node: Option<&Value>) -> Thumbs {
    let mut thumbs = Thumbs::default();
    let Some(urls) = node.and_then(Value::as_array) else {
        return thumbs;
    };
    let urls: Vec<String> = urls
        .iter()
        .filter_map(|x| x.get("url").and_then(Value::as_str))
        .map(normalize_url)
        .collect();
    if let Some(u) = urls.first() {
        thumbs.default = u.clone();
    }
    if let Some(u) = urls.get(urls.len() / 2) {
        thumbs.medium = u.clone();
    }
    if let Some(u) = urls.last() {
        thumbs.high = u.clone();
    }
    thumbs
}

/// InnerTube sometimes returns protocol-relative thumbnail URLs.
fn normalize_url(u: &str) -> String {
    if let Some(rest) = u.strip_prefix("//") {
        format!("https://{rest}")
    } else {
        u.to_string()
    }
}

// ---- related videos (next) -------------------------------------------------

const NEXT_URL: &str = "https://www.youtube.com/youtubei/v1/next?prettyPrint=false";
// WEB client for `next`, mirroring the Kodi plugin's `v1` client (no auth).
const WEB_CLIENT_VERSION: &str = "2.20250925.01.00";

/// Related ("up next") videos for a video, anonymous.
pub fn related(video_id: &str) -> Result<Vec<Video>, String> {
    let body = json!({
        "context": {"client": {"clientName": "WEB", "clientVersion": WEB_CLIENT_VERSION, "hl": "en", "gl": "US"}},
        "videoId": video_id,
    });
    let headers = [("X-YouTube-Client-Name", "1"), ("X-YouTube-Client-Version", WEB_CLIENT_VERSION)];
    let (status, text) = post_json(NEXT_URL, &body, &headers)?;
    let root: Value = serde_json::from_str(&text).map_err(|e| format!("next json (HTTP {status}): {e}"))?;
    Ok(parse_related(&root))
}

/// Home feed built from watch history (Kodi `get_related_for_home`): related
/// videos of each seed id, fetched in parallel and interleaved round-robin,
/// skipping `watched` ids and duplicates.
pub fn from_history(seeds: &[String], watched: &HashSet<String>) -> Vec<Video> {
    let lists = std::thread::scope(|scope| {
        let handles: Vec<_> = seeds.iter().map(|id| scope.spawn(move || related(id))).collect();
        handles
            .into_iter()
            .map(|handle| match handle.join() {
                Ok(Ok(videos)) => videos,
                Ok(Err(error)) => {
                    eprintln!("youtube: related: {error}");
                    Vec::new()
                }
                Err(_) => Vec::new(),
            })
            .collect()
    });
    super::interleave(lists, watched)
}

/// Videos from a WEB `next` response: secondary results as `lockupViewModel`
/// (current) or `compactVideoRenderer` (older layout); playlists/mixes skipped.
fn parse_related(root: &Value) -> Vec<Video> {
    let Some(results) = root
        .pointer("/contents/twoColumnWatchNextResults/secondaryResults/secondaryResults/results")
        .and_then(Value::as_array)
    else {
        return Vec::new();
    };
    results.iter().filter_map(|item| parse_lockup(item).or_else(|| parse_compact(item))).collect()
}

fn parse_lockup(item: &Value) -> Option<Video> {
    let lockup = item.get("lockupViewModel")?;
    if lockup.get("contentType").and_then(Value::as_str) != Some("LOCKUP_CONTENT_TYPE_VIDEO") {
        return None;
    }
    let id = lockup.get("contentId")?.as_str()?.to_string();
    let meta = lockup.pointer("/metadata/lockupMetadataViewModel")?;
    let title = meta.pointer("/title/content").and_then(Value::as_str).unwrap_or_default().to_string();
    let channel = meta
        .pointer("/metadata/contentMetadataViewModel/metadataRows/0/metadataParts/0/text/content")
        .and_then(Value::as_str)
        .unwrap_or_default()
        .to_string();
    let image = lockup.pointer("/contentImage/thumbnailViewModel");
    let duration = image
        .and_then(|i| i.get("overlays"))
        .and_then(Value::as_array)
        .and_then(|overlays| {
            overlays.iter().find_map(|o| {
                o.pointer("/thumbnailBottomOverlayViewModel/badges/0/thumbnailBadgeViewModel/text")
                    .and_then(Value::as_str)
            })
        })
        .map(parse_clock)
        .unwrap_or(0);
    let thumbs = thumbs_from(image.and_then(|i| i.pointer("/image/sources")));
    Some(Video { id, title, channel, duration, thumbs })
}

fn parse_compact(item: &Value) -> Option<Video> {
    let compact = item.get("compactVideoRenderer")?;
    Some(Video {
        id: compact.get("videoId")?.as_str()?.to_string(),
        title: text_of(compact.get("title")).unwrap_or_default(),
        channel: text_of(compact.get("longBylineText")).or_else(|| text_of(compact.get("shortBylineText")))
            .unwrap_or_default(),
        duration: text_of(compact.get("lengthText")).map(|t| parse_clock(&t)).unwrap_or(0),
        thumbs: thumbs_from(compact.pointer("/thumbnail/thumbnails")),
    })
}

/// "1:00:24" or "12:34" to seconds; 0 for non-clock badges such as "LIVE".
fn parse_clock(text: &str) -> u32 {
    let mut seconds = 0u32;
    for part in text.trim().split(':') {
        let Ok(n) = part.parse::<u32>() else { return 0 };
        seconds = seconds * 60 + n;
    }
    seconds
}

// ---- direct streams (player) -----------------------------------------------

/// Stream URLs for mpv: a video (or muxed/HLS) URL plus separate audio tracks
/// for adaptive formats, original first. URLs expire after roughly six hours.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Streams {
    pub video: String,
    pub audio: Vec<Audio>,
}

/// One audio track: `lang` is the BCP 47 tag ("de", "en-US"), `title` the
/// display name with its kind ("German (original)", "English (auto-dubbed)").
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Audio {
    pub url: String,
    pub lang: String,
    pub title: String,
}

/// Format selection limits. `codecs` lists the allowed video codecs in
/// preference order (av01, vp9, avc1); others are skipped. `audio_langs` are
/// primary language subtags whose dubs are offered beside the original.
#[derive(Debug, Clone)]
pub struct StreamPrefs {
    pub max_height: u32,
    pub codecs: Vec<String>,
    pub audio_langs: Vec<String>,
}

impl StreamPrefs {
    /// MEDIAS_YT_MAX_HEIGHT (default 1080), MEDIAS_YT_CODECS (default
    /// "av01,vp9,avc1"; "avc1" suits the Pi, which lacks AV1/VP9 hardware decode)
    /// and MEDIAS_YT_AUDIO_LANGS (default: the locale's languages).
    pub fn from_env() -> StreamPrefs {
        let max_height = std::env::var("MEDIAS_YT_MAX_HEIGHT").ok().and_then(|v| v.parse().ok()).unwrap_or(1080);
        let codecs = std::env::var("MEDIAS_YT_CODECS").unwrap_or_else(|_| "av01,vp9,avc1".into());
        let langs = std::env::var("MEDIAS_YT_AUDIO_LANGS").unwrap_or_else(|_| locale_langs());
        StreamPrefs { max_height, codecs: parse_codecs(&codecs), audio_langs: parse_langs(&langs) }
    }

    fn codec_rank(&self, codec: &str) -> Option<usize> {
        self.codecs.iter().position(|c| c == codec)
    }
}

fn parse_codecs(list: &str) -> Vec<String> {
    list.split(',').map(|c| c.trim().to_ascii_lowercase()).filter(|c| !c.is_empty()).collect()
}

/// LANGUAGE (colon list), else LC_ALL / LC_MESSAGES / LANG, as a comma list.
fn locale_langs() -> String {
    let var = |name: &str| std::env::var(name).ok().filter(|v| !v.is_empty());
    var("LANGUAGE").map(|v| v.replace(':', ","))
        .or_else(|| var("LC_ALL")).or_else(|| var("LC_MESSAGES")).or_else(|| var("LANG"))
        .unwrap_or_default()
}

/// "de_DE.UTF-8,en-US" -> ["de", "en"]; C and POSIX are dropped.
fn parse_langs(list: &str) -> Vec<String> {
    let mut langs: Vec<String> = Vec::new();
    for item in list.split(',') {
        let lang = primary_lang(item.trim());
        if !lang.is_empty() && lang != "c" && lang != "posix" && !langs.contains(&lang) {
            langs.push(lang);
        }
    }
    langs
}

fn primary_lang(tag: &str) -> String {
    tag.split(['_', '-', '.', '@']).next().unwrap_or("").to_ascii_lowercase()
}

/// An anonymous player client: header identity plus its `context.client`.
struct PlayerClient {
    name: &'static str,
    id: &'static str,
    version: &'static str,
    user_agent: &'static str,
    client: Value,
}

/// Clients in fallback order (Kodi `ios_testsuite_params`, then
/// `android_testsuite_params`).
fn player_clients() -> [PlayerClient; 2] {
    [
        PlayerClient {
            name: "ios",
            id: "5",
            version: "20.20.7",
            user_agent: "com.google.ios.youtube/20.20.7 (iPhone16,2; U; CPU iOS 18_5_0 like Mac OS X)",
            client: json!({
                "clientName": "IOS", "clientVersion": "20.20.7", "deviceMake": "Apple",
                "deviceModel": "iPhone16,2", "osName": "iOS", "osVersion": "18.5.0.22F76",
                "platform": "MOBILE", "hl": "en", "gl": "US",
            }),
        },
        PlayerClient {
            name: "android",
            id: "3",
            version: "20.10.38",
            user_agent: "com.google.android.youtube/20.10.38 (Linux; U; Android 15) gzip",
            client: json!({
                "clientName": "ANDROID", "clientVersion": "20.10.38", "androidSdkVersion": "32",
                "osName": "Android", "osVersion": "15", "platform": "MOBILE", "hl": "en", "gl": "US",
            }),
        },
    ]
}

/// Resolve a video id to direct stream URLs, trying each player client in turn.
pub fn streams(video_id: &str, prefs: &StreamPrefs) -> Result<Streams, String> {
    let mut errors = Vec::new();
    for client in player_clients() {
        let body = json!({
            "context": {"client": client.client},
            "videoId": video_id,
            "params": TESTSUITE_PARAMS,
            "contentCheckOk": true,
            "racyCheckOk": true,
        });
        let headers = [
            ("User-Agent", client.user_agent),
            ("X-YouTube-Client-Name", client.id),
            ("X-YouTube-Client-Version", client.version),
            ("Origin", "https://www.youtube.com"),
        ];
        let result = post_json(PLAYER_URL, &body, &headers)
            .and_then(|(_, text)| serde_json::from_str::<Value>(&text).map_err(|e| format!("player json: {e}")))
            .and_then(|root| select(&root, prefs));
        match result {
            Ok(streams) => return Ok(streams),
            Err(error) => errors.push(format!("{}: {error}", client.name)),
        }
    }
    Err(errors.join("; "))
}

/// Choose streams from a player response. Adaptive: the highest allowed video
/// (height <= max, codec in prefs, SDR) with the audio tracks of `audio_tracks`.
/// Then muxed progressive, then HLS (also used for live).
pub fn select(root: &Value, prefs: &StreamPrefs) -> Result<Streams, String> {
    let status = root.pointer("/playabilityStatus/status").and_then(Value::as_str).unwrap_or("");
    if status != "OK" {
        let reason = root.pointer("/playabilityStatus/reason").and_then(Value::as_str).unwrap_or("unplayable");
        return Err(format!("{status}: {reason}"));
    }
    let data = root.get("streamingData").ok_or("no streamingData")?;
    let hls = data.get("hlsManifestUrl").and_then(Value::as_str);
    let live = root.pointer("/videoDetails/isLive").and_then(Value::as_bool).unwrap_or(false);
    if live && let Some(hls) = hls {
        return Ok(Streams { video: hls.to_string(), audio: Vec::new() });
    }

    let adaptive: Vec<&Value> =
        data.get("adaptiveFormats").and_then(Value::as_array).map(|a| a.iter().filter(|f| playable(f)).collect())
            .unwrap_or_default();
    let video = adaptive
        .iter()
        .copied()
        .filter(|f| mime(f).starts_with("video/") && !is_hdr(f))
        .filter_map(|f| {
            let height = f.get("height").and_then(Value::as_u64)? as u32;
            let rank = prefs.codec_rank(&codec(f))?;
            (height > 0 && height <= prefs.max_height).then_some((height, std::cmp::Reverse(rank), bitrate(f), f))
        })
        .max_by_key(|&(height, rank, rate, _)| (height, rank, rate))
        .map(|(.., f)| f);
    let audio = audio_tracks(&adaptive, &prefs.audio_langs);
    if let Some(video) = video
        && !audio.is_empty()
    {
        return Ok(Streams { video: url(video)?, audio });
    }

    let muxed = data
        .get("formats")
        .and_then(Value::as_array)
        .and_then(|a| a.iter().filter(|f| playable(f)).max_by_key(|f| f.get("height").and_then(Value::as_u64)));
    if let Some(muxed) = muxed {
        return Ok(Streams { video: url(muxed)?, audio: Vec::new() });
    }
    if let Some(hls) = hls {
        return Ok(Streams { video: hls.to_string(), audio: Vec::new() });
    }
    Err("no playable stream URLs".into())
}

/// Audio content kind from the format URL's `xtags` ("acont=dubbed-auto:lang=de"):
/// original, dubbed, dubbed-auto, descriptive, ...; None without the tag.
fn audio_content(format: &Value) -> Option<String> {
    let query = format.get("url")?.as_str()?.split_once('?')?.1;
    let xtags = query.split('&').find_map(|kv| kv.strip_prefix("xtags="))?;
    let xtags = xtags.replace("%3D", "=").replace("%3A", ":").replace("%3d", "=").replace("%3a", ":");
    xtags.split(':').find_map(|tag| tag.strip_prefix("acont=")).map(str::to_string)
}

/// One track per `audioTrack.id` (best: non-DRC, then bitrate), kept when it is
/// the original or its language is in `langs`; original first, then `langs`
/// order. Each extra track costs mpv ~150 ms at load (measured, 24 tracks 4.5 s).
/// The `audioIsDefault` flag follows the request `hl`, so it marks a dub for
/// foreign-language videos and is used only when no track is tagged original.
fn audio_tracks(adaptive: &[&Value], langs: &[String]) -> Vec<Audio> {
    let mut best: Vec<(String, &Value)> = Vec::new();
    for &f in adaptive.iter().filter(|f| mime(f).starts_with("audio/")) {
        let id = f.pointer("/audioTrack/id").and_then(Value::as_str).unwrap_or("").to_string();
        match best.iter_mut().find(|(k, _)| *k == id) {
            Some((_, b)) if (!is_drc(f), bitrate(f)) > (!is_drc(b), bitrate(b)) => *b = f,
            Some(_) => {}
            None => best.push((id, f)),
        }
    }
    let tagged = best.iter().any(|(_, f)| audio_content(f).as_deref() == Some("original"));
    let original = |f: &Value| {
        best.len() == 1 || if tagged { audio_content(f).as_deref() == Some("original") } else { is_default_track(f) }
    };
    let mut tracks: Vec<(usize, Audio)> = best
        .iter()
        .filter_map(|&(ref id, f)| {
            let lang = id.split('.').next().unwrap_or("").to_string();
            let rank = if original(f) { 0 } else { 1 + langs.iter().position(|l| *l == primary_lang(&lang))? };
            let name = f.pointer("/audioTrack/displayName").and_then(Value::as_str).unwrap_or("");
            let name = name.trim_end_matches(" original").trim();
            let kind = match audio_content(f).as_deref() {
                Some("dubbed-auto") => "auto-dubbed".to_string(),
                Some(kind) => kind.to_string(),
                None if rank == 0 => "original".to_string(),
                None => String::new(),
            };
            let title = if name.is_empty() {
                if rank == 0 { "Original".to_string() } else { kind }
            } else if kind.is_empty() || name.to_ascii_lowercase().contains(&kind) {
                name.to_string()
            } else {
                format!("{name} ({kind})")
            };
            Some((rank, Audio { url: url(f).ok()?, lang, title }))
        })
        .collect();
    tracks.sort_by_key(|(rank, _)| *rank);
    tracks.into_iter().map(|(_, audio)| audio).collect()
}

/// A plain URL (not signatureCipher) that is not an OTF (segment-template) stream.
fn playable(format: &Value) -> bool {
    format.get("url").and_then(Value::as_str).is_some()
        && format.get("type").and_then(Value::as_str) != Some("FORMAT_STREAM_TYPE_OTF")
}

fn url(format: &Value) -> Result<String, String> {
    format.get("url").and_then(Value::as_str).map(str::to_string).ok_or_else(|| "format without url".into())
}

fn mime(format: &Value) -> &str {
    format.get("mimeType").and_then(Value::as_str).unwrap_or("")
}

fn bitrate(format: &Value) -> u64 {
    format.get("bitrate").and_then(Value::as_u64).unwrap_or(0)
}

/// Codec family from `video/mp4; codecs="av01.0.08M.08"`: av01, vp9 (incl.
/// vp09 profiles), avc1, ...
fn codec(format: &Value) -> String {
    let codecs = mime(format).split("codecs=\"").nth(1).unwrap_or("");
    let family = codecs.split([',', '"', '.']).next().unwrap_or("").to_ascii_lowercase();
    if family == "vp09" { "vp9".into() } else { family }
}

/// PQ (SMPTE ST 2084) or HLG transfer: skipped, the UI plane composites SDR.
fn is_hdr(format: &Value) -> bool {
    format
        .pointer("/colorInfo/transferCharacteristics")
        .and_then(Value::as_str)
        .is_some_and(|t| t.contains("2084") || t.contains("B67"))
}

/// True for the original/default audio track (or when no track info exists).
fn is_default_track(format: &Value) -> bool {
    match format.get("audioTrack") {
        Some(track) => track.get("audioIsDefault").and_then(Value::as_bool).unwrap_or(false),
        None => true,
    }
}

fn is_drc(format: &Value) -> bool {
    format.get("isDrc").and_then(Value::as_bool).unwrap_or(false)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[cfg(feature = "youtube-tv")]
    #[test]
    fn parses_tiles_from_a_tv_shelf_response() {
        let body = r#"{"contents":{"tvBrowseRenderer":{"content":{"tvSurfaceContentRenderer":
          {"content":{"sectionListRenderer":{"contents":[
            {"shelfRenderer":{"content":{"horizontalListRenderer":{"items":[
              {"tileRenderer":{
                "onSelectCommand":{"watchEndpoint":{"videoId":"vid123"}},
                "metadata":{"tileMetadataRenderer":{
                  "title":{"simpleText":"Cool Video"},
                  "lines":[{"lineRenderer":{"items":[{"lineItemRenderer":
                    {"text":{"runs":[{"text":"Some Channel"}]}}}]}}]}},
                "header":{"tileHeaderRenderer":{"thumbnail":{"thumbnails":[
                  {"url":"//i.ytimg.com/s.jpg","width":320,"height":180}]}}}}},
              {"tileRenderer":{"onSelectCommand":{"watchEndpoint":{"videoId":"vid123"}},
                "metadata":{"tileMetadataRenderer":{"title":{"simpleText":"Dup"}}}}}
            ]}}}}
          ]}}}}}}}"#;
        let videos = parse_recommendations(&serde_json::from_str(body).unwrap());
        assert_eq!(videos.len(), 1); // the duplicate id is dropped
        let v = &videos[0];
        assert_eq!((v.id.as_str(), v.title.as_str(), v.channel.as_str()), ("vid123", "Cool Video", "Some Channel"));
        assert_eq!(v.thumbs.high, "https://i.ytimg.com/s.jpg");
    }

    #[cfg(feature = "youtube-tv")]
    #[test]
    fn missing_feed_yields_no_videos() {
        assert!(parse_recommendations(&json!({"contents": {}})).is_empty());
    }

    /// Network: `cargo test -- --ignored history_feed`.
    #[test]
    #[ignore]
    fn history_feed_returns_unwatched_related_videos() {
        let seeds = ["V_uq3v6xK-4".to_string(), "WXELsIk4o0g".to_string()];
        let watched: HashSet<String> = seeds.iter().cloned().collect();
        let videos = from_history(&seeds, &watched);
        assert!(videos.len() >= 10, "only {} videos", videos.len());
        assert!(videos.iter().all(|v| !watched.contains(&v.id) && v.id.len() == 11 && !v.title.is_empty()));
        let unique: HashSet<&str> = videos.iter().map(|v| v.id.as_str()).collect();
        assert_eq!(unique.len(), videos.len());
    }

    #[test]
    fn parses_related_lockups_and_compact_renderers() {
        let body = json!({"contents": {"twoColumnWatchNextResults": {"secondaryResults": {"secondaryResults": {"results": [
            {"lockupViewModel": {"contentType": "LOCKUP_CONTENT_TYPE_VIDEO", "contentId": "fsLh-NYhOoU",
                "metadata": {"lockupMetadataViewModel": {"title": {"content": "Formula"},
                    "metadata": {"contentMetadataViewModel": {"metadataRows": [
                        {"metadataParts": [{"text": {"content": "3Blue1Brown"}}]},
                        {"metadataParts": [{"text": {"content": "1.5M"}}]}]}}}},
                "contentImage": {"thumbnailViewModel": {
                    "image": {"sources": [{"url": "https://i.ytimg.com/a.jpg"}, {"url": "https://i.ytimg.com/b.jpg"}]},
                    "overlays": [{"thumbnailBottomOverlayViewModel": {"badges": [
                        {"thumbnailBadgeViewModel": {"text": "1:00:24"}}]}}]}}}},
            {"lockupViewModel": {"contentType": "LOCKUP_CONTENT_TYPE_PLAYLIST", "contentId": "RDxyz"}},
            {"compactVideoRenderer": {"videoId": "abcdefghijk", "title": {"simpleText": "Old"},
                "longBylineText": {"runs": [{"text": "Chan"}]}, "lengthText": {"simpleText": "12:34"}}},
            {"continuationItemRenderer": {}}
        ]}}}}});
        let videos = parse_related(&body);
        assert_eq!(videos.len(), 2); // the playlist and continuation are skipped
        assert_eq!((videos[0].id.as_str(), videos[0].title.as_str(), videos[0].channel.as_str()),
            ("fsLh-NYhOoU", "Formula", "3Blue1Brown"));
        assert_eq!((videos[0].duration, videos[0].thumbs.high.as_str()), (3624, "https://i.ytimg.com/b.jpg"));
        assert_eq!((videos[1].id.as_str(), videos[1].channel.as_str(), videos[1].duration), ("abcdefghijk", "Chan", 754));
        assert_eq!(parse_clock("LIVE"), 0);
    }

    fn prefs(max_height: u32, codecs: &str) -> StreamPrefs {
        StreamPrefs { max_height, codecs: parse_codecs(codecs), audio_langs: Vec::new() }
    }

    fn player(adaptive: Value) -> Value {
        json!({"playabilityStatus": {"status": "OK"}, "streamingData": {"adaptiveFormats": adaptive,
            "formats": [{"itag": 18, "url": "muxed", "mimeType": "video/mp4; codecs=\"avc1.42001E, mp4a.40.2\"", "height": 360}],
            "hlsManifestUrl": "hls"}})
    }

    fn sample() -> Value {
        player(json!([
            {"url": "av1-2160", "mimeType": "video/mp4; codecs=\"av01.0.12M.08\"", "height": 2160, "bitrate": 9},
            {"url": "av1-1080", "mimeType": "video/mp4; codecs=\"av01.0.08M.08\"", "height": 1080, "bitrate": 5},
            {"url": "vp9-1080", "mimeType": "video/webm; codecs=\"vp9\"", "height": 1080, "bitrate": 6},
            {"url": "avc-720", "mimeType": "video/mp4; codecs=\"avc1.4d401f\"", "height": 720, "bitrate": 3},
            {"url": "hdr-1080", "mimeType": "video/webm; codecs=\"vp09.02.51.10\"", "height": 1080, "bitrate": 8,
             "colorInfo": {"transferCharacteristics": "COLOR_TRANSFER_CHARACTERISTICS_SMPTEST2084"}},
            {"url": "otf-1080", "mimeType": "video/mp4; codecs=\"av01.0.08M.08\"", "height": 1080, "bitrate": 9,
             "type": "FORMAT_STREAM_TYPE_OTF"},
            {"signatureCipher": "s=x&url=y", "mimeType": "video/mp4; codecs=\"av01.0.08M.08\"", "height": 1080},
            // audioIsDefault follows the request hl (here "de"), not the original.
            {"url": "de?xtags=acont%3Ddubbed%3Alang%3Dde", "mimeType": "audio/webm; codecs=\"opus\"", "bitrate": 200,
             "audioTrack": {"id": "de.3", "displayName": "German", "audioIsDefault": true}},
            {"url": "fr?xtags=acont%3Ddubbed-auto%3Alang%3Dfr", "mimeType": "audio/webm; codecs=\"opus\"", "bitrate": 200,
             "audioTrack": {"id": "fr.3", "displayName": "French"}},
            {"url": "drc?xtags=acont%3Doriginal%3Adrc%3D1%3Alang%3Den-US", "mimeType": "audio/webm; codecs=\"opus\"",
             "bitrate": 180, "isDrc": true, "audioTrack": {"id": "en-US.4", "displayName": "English (US) original"}},
            {"url": "opus?xtags=acont%3Doriginal%3Alang%3Den-US", "mimeType": "audio/webm; codecs=\"opus\"", "bitrate": 160,
             "audioTrack": {"id": "en-US.4", "displayName": "English (US) original"}},
            {"url": "aac?xtags=acont%3Doriginal%3Alang%3Den-US", "mimeType": "audio/mp4; codecs=\"mp4a.40.2\"", "bitrate": 128,
             "audioTrack": {"id": "en-US.4", "displayName": "English (US) original"}}
        ]))
    }

    fn audio(url: &str, lang: &str, title: &str) -> Audio {
        Audio { url: url.into(), lang: lang.into(), title: title.into() }
    }

    fn original() -> Audio {
        audio("opus?xtags=acont%3Doriginal%3Alang%3Den-US", "en-US", "English (US) (original)")
    }

    #[test]
    fn selects_highest_allowed_sdr_video_with_default_audio() {
        // 2160 exceeds the cap; HDR, OTF, and ciphered formats are skipped; av01
        // outranks vp9 at equal height; without audio languages only the
        // original (non-DRC, highest bitrate) remains.
        let s = select(&sample(), &prefs(1080, "av01,vp9,avc1")).unwrap();
        assert_eq!(s, Streams { video: "av1-1080".into(), audio: vec![original()] });
        assert_eq!(select(&sample(), &prefs(2160, "av01,vp9,avc1")).unwrap().video, "av1-2160");
    }

    #[test]
    fn codec_list_restricts_and_orders_video() {
        assert_eq!(select(&sample(), &prefs(1080, "vp9,av01")).unwrap().video, "vp9-1080");
        assert_eq!(select(&sample(), &prefs(1080, "avc1")).unwrap().video, "avc-720");
        // No allowed adaptive video: fall back to the muxed progressive format.
        assert_eq!(select(&sample(), &prefs(1080, "hev1")).unwrap(), Streams { video: "muxed".into(), audio: Vec::new() });
    }

    #[test]
    fn dubs_in_preferred_languages_follow_the_original() {
        let mut p = prefs(1080, "av01");
        p.audio_langs = parse_langs("fr_FR.UTF-8,de-AT,C");
        assert_eq!(p.audio_langs, ["fr", "de"]);
        assert_eq!(select(&sample(), &p).unwrap().audio, [
            original(),
            audio("fr?xtags=acont%3Ddubbed-auto%3Alang%3Dfr", "fr", "French (auto-dubbed)"),
            audio("de?xtags=acont%3Ddubbed%3Alang%3Dde", "de", "German (dubbed)"),
        ]);
    }

    /// Network: siOlmWVhefE is German with an English auto-dub that YouTube
    /// flags audioIsDefault for hl=en. `cargo test -- --ignored german_original`.
    #[test]
    #[ignore]
    fn german_original_wins_over_the_english_auto_dub() {
        let mut p = prefs(1080, "av01,vp9,avc1");
        let titles = |p: &StreamPrefs| -> Vec<String> {
            streams("siOlmWVhefE", p).unwrap().audio.into_iter().map(|a| a.title).collect()
        };
        assert_eq!(titles(&p), ["German (DE) (original)"]);
        p.audio_langs = vec!["en".into()];
        assert_eq!(titles(&p), ["German (DE) (original)", "English (US) (auto-dubbed)"]);
    }

    #[test]
    fn untagged_tracks_fall_back_to_the_default_flag() {
        let tagged = [json!({"url": "a", "mimeType": "audio/mp4", "audioTrack": {"id": "de.4", "displayName": "Deutsch", "audioIsDefault": true}}),
            json!({"url": "b", "mimeType": "audio/mp4", "audioTrack": {"id": "en.3", "displayName": "Englisch"}})];
        let refs: Vec<&Value> = tagged.iter().collect();
        assert_eq!(audio_tracks(&refs, &[]), [audio("a", "de", "Deutsch (original)")]);
        let single = json!({"url": "c", "mimeType": "audio/mp4"});
        assert_eq!(audio_tracks(&[&single], &[]), [audio("c", "", "Original")]);
    }

    #[test]
    fn live_uses_hls_and_unplayable_reports_the_reason() {
        let mut live = sample();
        live["videoDetails"] = json!({"isLive": true});
        assert_eq!(select(&live, &prefs(1080, "av01")).unwrap().video, "hls");
        let blocked = json!({"playabilityStatus": {"status": "LOGIN_REQUIRED", "reason": "Sign in"}});
        assert_eq!(select(&blocked, &prefs(1080, "av01")).unwrap_err(), "LOGIN_REQUIRED: Sign in");
    }
}