// Phase 7 — `stream_info(url)` via Sulkta-OSS/strawcore-core.
// Exposed as a suspend fun.
//
// StreamInfo/AudioStreamItem/VideoStreamItem field shapes are unchanged
// from Phase U-3 so Kotlin VideoDetailScreen + PlayerScreen +
// ResolvedPlayback consume them with zero code changes.

use strawcore_core::youtube::linkhandler::stream::extract_video_id;
use strawcore_core::youtube::stream_extractor::stream_info as core_stream_info;
use strawcore_core::youtube::stream_extractor::stream_metadata as core_stream_metadata;

use crate::error::StrawcoreError;
use crate::search::SearchItem;

#[derive(Debug, Clone, uniffi::Record)]
pub struct StreamInfo {
    pub id: String,
    pub title: String,
    pub uploader: String,
    pub uploader_url: Option<String>,
    pub description: String,
    pub thumbnail: Option<String>,
    pub view_count: i64,
    pub like_count: i64,
    /// Duration in seconds. 0 = live/unknown.
    pub duration_seconds: i64,

    /// Progressive (audio+video combined). Empty when YT only serves DASH.
    pub combined: Vec<VideoStreamItem>,
    /// DASH/adaptive video-only streams. Pair with `audio_only` via MergingMediaSource.
    pub video_only: Vec<VideoStreamItem>,
    /// DASH/adaptive audio-only streams. Sort by bitrate desc for "best audio".
    pub audio_only: Vec<AudioStreamItem>,
    /// Optional DASH MPD URL. ExoPlayer's DashMediaSource accepts this directly.
    pub dash_mpd_url: Option<String>,
    /// Optional HLS playlist URL. ExoPlayer's HlsMediaSource accepts this directly.
    pub hls_url: Option<String>,

    /// "Up next" list. Empty for now — populated when we port /next response.
    pub related: Vec<SearchItem>,
}

#[derive(Debug, Clone, uniffi::Record)]
pub struct VideoStreamItem {
    pub url: String,
    /// e.g. 1080, 720, 480.
    pub height: i32,
    pub bitrate: i64,
    pub mime_type: String,
}

#[derive(Debug, Clone, uniffi::Record)]
pub struct AudioStreamItem {
    pub url: String,
    pub bitrate: i64,
    pub mime_type: String,
}

/// The player-facing URLs picked from a [`StreamInfo`]'s stream lists under
/// a resolution ceiling. This is the stream-selection policy that used to
/// live in the Kotlin `resolveStreamPlayback`; the app now keeps only a thin
/// shim that supplies the ceiling (its `Settings.maxResolution`) and attaches
/// SponsorBlock segments on top. SponsorBlock is deliberately NOT here — it's
/// a separate concern the app layers over this.
#[derive(Debug, Clone, uniffi::Record)]
pub struct ResolvedStreams {
    pub title: String,
    pub video_url: Option<String>,
    pub audio_url: Option<String>,
    pub combined_url: Option<String>,
    pub dash_mpd_url: Option<String>,
    pub hls_url: Option<String>,
}

#[uniffi::export(async_runtime = "tokio")]
pub async fn stream_info(input: String) -> Result<StreamInfo, StrawcoreError> {
    log::info!("strawcore::stream_info input_len={}", input.len());
    crate::runtime::ensure_initialized();
    let video_id = resolve_video_id(&input)?;
    let video_id_for_call = video_id.clone();
    let core = crate::runtime::run_extract("stream_info", move || {
        core_stream_info(&video_id_for_call)
    })
    .await?;
    Ok(map_stream_info(video_id, core))
}

/// Metadata-only fetch — returns `(view_count, duration_seconds)` from the
/// Android `videoDetails`, skipping the JS-deobf / streams / extra WEB
/// round-trip the full `stream_info` pays. Backs `enrich_feed_item`, which
/// only needs those two fields. Non-negative clamping mirrors
/// `map_stream_info` so the values are identical to the full path's.
pub async fn stream_metadata(input: String) -> Result<(i64, i64), StrawcoreError> {
    log::info!("strawcore::stream_metadata input_len={}", input.len());
    crate::runtime::ensure_initialized();
    let video_id = resolve_video_id(&input)?;
    let core = crate::runtime::run_extract("stream_metadata", move || {
        core_stream_metadata(&video_id)
    })
    .await?;
    Ok((clamp_nonneg(core.view_count), core.duration_seconds.max(0)))
}

fn resolve_video_id(input: &str) -> Result<String, StrawcoreError> {
    let trimmed = input.trim();
    // Bare 11-char id?
    if trimmed.len() == 11
        && trimmed
            .chars()
            .all(|c| c.is_ascii_alphanumeric() || c == '_' || c == '-')
    {
        return Ok(trimmed.to_string());
    }
    extract_video_id(trimmed).map_err(|e| StrawcoreError::Unsupported {
        detail: e.to_string(),
    })
}

fn map_stream_info(
    video_id: String,
    s: strawcore_core::stream::StreamInfo,
) -> StreamInfo {
    let combined = s
        .video_streams
        .into_iter()
        .map(video_to_dto)
        .collect();
    let video_only = s
        .video_only_streams
        .into_iter()
        .map(video_to_dto)
        .collect();
    let audio_only = s.audio_streams.into_iter().map(audio_to_dto).collect();
    let uploader_url = if s.uploader_url.is_empty() {
        None
    } else {
        Some(s.uploader_url)
    };
    let thumbnail = s.thumbnails.last().map(|i| i.url().to_string());

    StreamInfo {
        id: video_id,
        title: s.name,
        uploader: s.uploader_name,
        uploader_url,
        description: s.description,
        thumbnail,
        view_count: clamp_nonneg(s.view_count),
        like_count: clamp_nonneg(s.like_count),
        duration_seconds: s.duration_seconds.max(0),
        combined,
        video_only,
        audio_only,
        dash_mpd_url: s.dash_manifest_url,
        hls_url: s.hls_manifest_url,
        related: Vec::new(),
    }
}

fn clamp_nonneg(n: i64) -> i64 {
    if n < 0 {
        0
    } else {
        n
    }
}

fn video_to_dto(v: strawcore_core::stream::VideoStream) -> VideoStreamItem {
    VideoStreamItem {
        url: v.url,
        height: v.height.map(|h| h as i32).unwrap_or(0),
        bitrate: v.bandwidth.map(|b| b as i64).unwrap_or(0),
        mime_type: v.format.mime().to_string(),
    }
}

fn audio_to_dto(a: strawcore_core::stream::AudioStream) -> AudioStreamItem {
    AudioStreamItem {
        url: a.url,
        bitrate: a
            .average_bitrate_kbps
            .map(|b| (b as i64) * 1000)
            .unwrap_or(0),
        mime_type: a.format.mime().to_string(),
    }
}

/// Pick the player URLs from an already-fetched [`StreamInfo`]. Pure +
/// synchronous (no network). `max_height` is the app's
/// `Settings.maxResolution` ceiling — `Int.MAX_VALUE` means "no cap". This
/// is a byte-for-byte port of the prior Kotlin `resolveStreamPlayback`:
/// the app keeps a thin shim that passes the ceiling and tacks on
/// SponsorBlock segments.
#[uniffi::export]
pub fn resolve_playback(info: StreamInfo, max_height: i32) -> ResolvedStreams {
    // Borrow the stream lists for selection before moving the owned String
    // fields into the result struct (disjoint fields, so this is fine).
    let video_url = pick_video(&info.video_only, max_height);
    let audio_url = pick_audio(&info.audio_only);
    let combined_url = pick_video(&info.combined, max_height);
    ResolvedStreams {
        title: info.title,
        video_url,
        audio_url,
        combined_url,
        // Kotlin used `takeIf { it.isNotBlank() }` — empty OR all-whitespace
        // collapses to None.
        dash_mpd_url: info.dash_mpd_url.filter(|s| !s.trim().is_empty()),
        hls_url: info.hls_url.filter(|s| !s.trim().is_empty()),
    }
}

/// Highest-bitrate video stream at or below `max_height`; if none fit, the
/// lowest-height stream (so a too-high-only set still plays without blowing
/// a data plan). The FIRST element wins ties — matching Kotlin's
/// `maxByOrNull`/`minByOrNull`, which keep the first max/min, unlike Rust's
/// `Iterator::max_by_key` (last on ties). Preserving that keeps the picked
/// URL identical to the previous Kotlin picker on same-bitrate/-height ties.
fn pick_video(streams: &[VideoStreamItem], max_height: i32) -> Option<String> {
    if streams.is_empty() {
        return None;
    }
    let mut best_capped: Option<&VideoStreamItem> = None;
    for s in streams.iter().filter(|s| s.height <= max_height) {
        match best_capped {
            // Keep the existing pick unless this one is strictly higher
            // bitrate — first-on-ties, matching `maxByOrNull`.
            Some(b) if b.bitrate >= s.bitrate => {}
            _ => best_capped = Some(s),
        }
    }
    if let Some(s) = best_capped {
        return Some(s.url.clone());
    }
    let mut lowest: Option<&VideoStreamItem> = None;
    for s in streams {
        match lowest {
            // First-on-ties, matching `minByOrNull`.
            Some(b) if b.height <= s.height => {}
            _ => lowest = Some(s),
        }
    }
    lowest.map(|s| s.url.clone())
}

/// Highest-bitrate audio stream, first-on-ties (matching Kotlin
/// `maxByOrNull { it.bitrate }`).
fn pick_audio(streams: &[AudioStreamItem]) -> Option<String> {
    let mut best: Option<&AudioStreamItem> = None;
    for s in streams {
        match best {
            Some(b) if b.bitrate >= s.bitrate => {}
            _ => best = Some(s),
        }
    }
    best.map(|s| s.url.clone())
}