//! Deterministic chunking and transcode scaffolding.

use ac_ffmpeg::format::{
    demuxer::Demuxer,
    io::IO,
    muxer::{Muxer, OutputFormat},
};
use anyhow::{anyhow, Context, Result};
use ec_core::{
    merkle_root_from_hashes, DeterminismProfile, ManifestBody, StreamId, StreamMetadata,
};
use ec_ts::{SectionAssembler, TimeSyncEngine, TimeSyncUpdate, TsReader};
use serde::{Deserialize, Serialize};
use std::fs;
use std::io::{Read, Write};
use std::path::{Path, PathBuf};
use std::process::{Child, Command, Stdio};
use std::time::Duration;

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct StreamProbe {
    pub index: usize,
    pub kind: String,
    pub decoder: Option<String>,
    pub width: Option<usize>,
    pub height: Option<usize>,
    pub sample_rate: Option<u32>,
    pub channels: Option<u32>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum ChunkFormat {
    Fmp4,
    MpegTs,
    Matroska,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ChunkerConfig {
    pub output_dir: PathBuf,
    pub segment_duration_ms: u64,
    pub segment_template: String,
    pub format: ChunkFormat,
    pub profile: DeterminismProfile,
}

impl ChunkerConfig {
    pub fn default_segment_template() -> String {
        "segment_%06d.m4s".to_string()
    }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ChunkSegment {
    pub index: usize,
    pub path: PathBuf,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ChunkManifest {
    pub output_dir: PathBuf,
    pub segments: Vec<ChunkSegment>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct TsChunk {
    pub index: u64,
    pub path: PathBuf,
    pub timing: ChunkTiming,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct HashedTsChunk {
    pub index: u64,
    pub path: PathBuf,
    pub timing: ChunkTiming,
    pub hash: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct HashedTsChunkManifest {
    pub output_dir: PathBuf,
    pub chunks: Vec<HashedTsChunk>,
    pub merkle_root: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ChunkTiming {
    pub chunk_index: u64,
    pub chunk_start_27mhz: Option<u64>,
    pub chunk_duration_27mhz: u64,
    pub utc_start_unix: Option<i64>,
    pub sync_status: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct TsChunkManifest {
    pub output_dir: PathBuf,
    pub chunks: Vec<TsChunk>,
}

#[derive(Debug, Clone)]
pub enum ChunkerInput {
    Url(String),
    File(PathBuf),
}

#[derive(Debug)]
pub struct SegmenterProcess {
    pub child: Child,
    pub output_dir: PathBuf,
}

#[derive(Debug, Clone)]
pub struct FfmpegCliSegmenter {
    pub ffmpeg_bin: PathBuf,
}

impl Default for FfmpegCliSegmenter {
    fn default() -> Self {
        Self {
            ffmpeg_bin: PathBuf::from("ffmpeg"),
        }
    }
}

impl FfmpegCliSegmenter {
    pub fn spawn(&self, input: ChunkerInput, config: &ChunkerConfig) -> Result<SegmenterProcess> {
        fs::create_dir_all(&config.output_dir)
            .with_context(|| format!("failed to create {}", config.output_dir.display()))?;

        let input_arg = match input {
            ChunkerInput::Url(url) => url,
            ChunkerInput::File(path) => path
                .to_str()
                .ok_or_else(|| anyhow!("invalid input path"))?
                .to_string(),
        };

        let segment_time = format!("{:.3}", config.segment_duration_ms as f64 / 1000.0);
        let output_template = config.output_dir.join(&config.segment_template);
        let output_template = output_template
            .to_str()
            .ok_or_else(|| anyhow!("invalid output template path"))?
            .to_string();

        let mut cmd = Command::new(&self.ffmpeg_bin);
        cmd.arg("-hide_banner")
            .arg("-loglevel")
            .arg("error")
            .arg("-nostdin")
            .arg("-y")
            .arg("-i")
            .arg(&input_arg);

        for arg in ffmpeg_profile_args(&config.profile) {
            cmd.arg(arg);
        }

        cmd.arg("-f")
            .arg("segment")
            .arg("-segment_time")
            .arg(segment_time)
            .arg("-reset_timestamps")
            .arg("1")
            .arg("-segment_format")
            .arg(segment_format_arg(&config.format))
            .arg(&output_template)
            .stdin(Stdio::null())
            .stdout(Stdio::null())
            .stderr(Stdio::inherit());

        let child = cmd
            .spawn()
            .with_context(|| "failed to spawn ffmpeg".to_string())?;

        Ok(SegmenterProcess {
            child,
            output_dir: config.output_dir.clone(),
        })
    }
}

pub fn collect_segments(output_dir: &Path) -> Result<ChunkManifest> {
    let mut entries = fs::read_dir(output_dir)?
        .filter_map(Result::ok)
        .filter(|entry| entry.file_type().map(|t| t.is_file()).unwrap_or(false))
        .map(|entry| entry.path())
        .collect::<Vec<_>>();

    entries.sort();

    let segments = entries
        .into_iter()
        .enumerate()
        .map(|(index, path)| ChunkSegment { index, path })
        .collect();

    Ok(ChunkManifest {
        output_dir: output_dir.to_path_buf(),
        segments,
    })
}

pub fn probe_read_stream<T: Read>(stream: T) -> Result<Vec<StreamProbe>> {
    let io = IO::from_read_stream(stream);
    let demuxer = Demuxer::builder()
        .build(io)
        .map_err(|err| anyhow!(err.to_string()))?;
    let demuxer = demuxer
        .find_stream_info(Some(Duration::from_secs(2)))
        .map_err(|(_, err)| anyhow!(err.to_string()))?;

    let mut probes = Vec::new();
    for (index, stream) in demuxer.streams().iter().enumerate() {
        let params = stream.codec_parameters();
        let mut probe = StreamProbe {
            index,
            kind: if params.is_video_codec() {
                "video".to_string()
            } else if params.is_audio_codec() {
                "audio".to_string()
            } else if params.is_subtitle_codec() {
                "subtitle".to_string()
            } else {
                "data".to_string()
            },
            decoder: params.decoder_name().map(|name| name.to_string()),
            width: None,
            height: None,
            sample_rate: None,
            channels: None,
        };

        if let Some(video) = params.as_video_codec_parameters() {
            probe.width = Some(video.width());
            probe.height = Some(video.height());
        }

        if let Some(audio) = params.as_audio_codec_parameters() {
            probe.sample_rate = Some(audio.sample_rate());
            probe.channels = Some(audio.channel_layout().channels());
        }

        probes.push(probe);
    }

    Ok(probes)
}

pub fn analyze_ts_time<T: Read>(
    stream: T,
    chunk_duration_ms: u64,
    max_events: usize,
) -> Result<Vec<TimeSyncUpdate>> {
    let mut reader = TsReader::new(stream);
    let mut assembler = SectionAssembler::default();
    let mut engine = TimeSyncEngine::new(chunk_duration_ms);
    let mut events = Vec::new();

    while let Some(packet) = reader.read_packet()? {
        for update in engine.ingest_packet(&packet, &mut assembler) {
            events.push(update);
            if events.len() >= max_events {
                return Ok(events);
            }
        }
    }

    Ok(events)
}

pub fn chunk_ts_stream<T: Read>(
    stream: T,
    output_dir: &Path,
    chunk_duration_ms: u64,
    max_chunks: Option<usize>,
) -> Result<TsChunkManifest> {
    let mut chunks = Vec::new();
    chunk_ts_stream_live(stream, output_dir, chunk_duration_ms, max_chunks, |chunk| {
        chunks.push(chunk);
        Ok(())
    })?;
    Ok(TsChunkManifest {
        output_dir: output_dir.to_path_buf(),
        chunks,
    })
}

pub fn chunk_ts_stream_live<T: Read, F: FnMut(TsChunk) -> Result<()>>(
    stream: T,
    output_dir: &Path,
    chunk_duration_ms: u64,
    max_chunks: Option<usize>,
    mut on_chunk: F,
) -> Result<()> {
    fs::create_dir_all(output_dir)
        .with_context(|| format!("failed to create {}", output_dir.display()))?;

    let mut reader = TsReader::new(stream);
    let mut assembler = SectionAssembler::default();
    let mut engine = TimeSyncEngine::new(chunk_duration_ms);

    let mut current_index: Option<u64> = None;
    let mut current_file: Option<std::fs::File> = None;
    let mut current_timing: Option<ChunkTiming> = None;
    let mut emitted = 0usize;

    let mut close_and_emit =
        |index: u64, timing: ChunkTiming, file: std::fs::File| -> Result<bool> {
            drop(file);
            let path = chunk_path(output_dir, index);
            on_chunk(TsChunk {
                index,
                path,
                timing,
            })?;
            emitted += 1;
            Ok(max_chunks.map(|limit| emitted >= limit).unwrap_or(false))
        };

    while let Some(packet) = reader.read_packet()? {
        let updates = engine.ingest_packet(&packet, &mut assembler);
        for update in updates {
            if update.discontinuity {
                if let (Some(index), Some(timing), Some(file)) = (
                    current_index.take(),
                    current_timing.take(),
                    current_file.take(),
                ) {
                    if close_and_emit(index, timing, file)? {
                        return Ok(());
                    }
                }
            }

            if let Some(index) = update.chunk_index {
                if current_index != Some(index) {
                    if let (Some(prev_index), Some(timing), Some(file)) = (
                        current_index.take(),
                        current_timing.take(),
                        current_file.take(),
                    ) {
                        if close_and_emit(prev_index, timing, file)? {
                            return Ok(());
                        }
                    }

                    let path = chunk_path(output_dir, index);
                    let file = std::fs::File::create(&path)
                        .with_context(|| format!("failed to create {}", path.display()))?;
                    current_file = Some(file);
                    current_index = Some(index);
                    current_timing = Some(ChunkTiming {
                        chunk_index: index,
                        chunk_start_27mhz: update.chunk_start_27mhz,
                        chunk_duration_27mhz: chunk_duration_ms * 27_000,
                        utc_start_unix: update.utc_start_unix,
                        sync_status: if update.synced {
                            "synced".to_string()
                        } else {
                            "unsynced".to_string()
                        },
                    });
                }
            }
        }

        if let Some(file) = current_file.as_mut() {
            file.write_all(packet.as_bytes())?;
        }
    }

    if let (Some(index), Some(timing), Some(file)) = (
        current_index.take(),
        current_timing.take(),
        current_file.take(),
    ) {
        let _ = close_and_emit(index, timing, file);
    }

    Ok(())
}

fn chunk_path(output_dir: &Path, index: u64) -> PathBuf {
    output_dir.join(format!("chunk_{index:010}.ts"))
}

pub fn hash_file_blake3(path: &Path) -> Result<String> {
    let mut file =
        fs::File::open(path).with_context(|| format!("failed to open {}", path.display()))?;
    let mut hasher = blake3::Hasher::new();
    let mut buffer = [0u8; 8192];
    loop {
        let read = file.read(&mut buffer)?;
        if read == 0 {
            break;
        }
        hasher.update(&buffer[..read]);
    }
    Ok(hasher.finalize().to_hex().to_string())
}

pub fn chunk_stream_ffmpeg<T: Read>(
    stream: T,
    output_dir: &Path,
    chunk_duration_ms: u64,
    max_chunks: Option<usize>,
) -> Result<TsChunkManifest> {
    fs::create_dir_all(output_dir)
        .with_context(|| format!("failed to create {}", output_dir.display()))?;

    let io = IO::from_read_stream(stream);
    let demuxer = Demuxer::builder()
        .build(io)
        .map_err(|err| anyhow!(err.to_string()))?;
    let demuxer = demuxer
        .find_stream_info(Some(Duration::from_secs(2)))
        .map_err(|(_, err)| anyhow!(err.to_string()))?;

    let stream_info = demuxer
        .streams()
        .iter()
        .map(|stream| (stream.codec_parameters(), stream.time_base()))
        .collect::<Vec<_>>();

    let mut demuxer = demuxer.into_demuxer();
    let chunk_duration_micros = chunk_duration_ms as i64 * 1000;

    let mut chunks = Vec::new();
    let mut current_index: Option<u64> = None;
    let mut current_muxer: Option<Muxer<std::fs::File>> = None;
    let mut current_timing: Option<ChunkTiming> = None;

    loop {
        let Some(packet) = demuxer.take().map_err(|err| anyhow!(err.to_string()))? else {
            break;
        };

        let ts = packet
            .pts()
            .as_micros()
            .or_else(|| packet.dts().as_micros());

        let chunk_index = ts
            .and_then(|micros| {
                if micros < 0 {
                    None
                } else {
                    Some((micros / chunk_duration_micros) as u64)
                }
            })
            .or(current_index);

        if let Some(index) = chunk_index {
            if current_index != Some(index) {
                if let Some(mut muxer) = current_muxer.take() {
                    muxer.flush().map_err(|err| anyhow!(err.to_string()))?;
                    let _ = muxer.close();
                }
                if let (Some(prev_index), Some(timing)) =
                    (current_index.take(), current_timing.take())
                {
                    chunks.push(TsChunk {
                        index: prev_index,
                        path: chunk_path(output_dir, prev_index),
                        timing,
                    });
                }

                let path = chunk_path(output_dir, index);
                let file = std::fs::File::create(&path)
                    .with_context(|| format!("failed to create {}", path.display()))?;
                let io = IO::from_write_stream(file);
                let mut builder = Muxer::builder();
                for (params, _) in &stream_info {
                    builder
                        .add_stream(params)
                        .map_err(|err| anyhow!(err.to_string()))?;
                }
                for (stream, (_, tb)) in builder.streams_mut().iter_mut().zip(stream_info.iter()) {
                    stream.set_time_base(*tb);
                }
                let format = OutputFormat::find_by_name("mpegts")
                    .ok_or_else(|| anyhow!("mpegts format not found"))?;
                let muxer = builder
                    .interleaved(true)
                    .build(io, format)
                    .map_err(|err| anyhow!(err.to_string()))?;

                current_muxer = Some(muxer);
                current_index = Some(index);
                current_timing = Some(ChunkTiming {
                    chunk_index: index,
                    chunk_start_27mhz: ts.map(|micros| (micros as u64) * 27),
                    chunk_duration_27mhz: chunk_duration_ms * 27_000,
                    utc_start_unix: None,
                    sync_status: "pts".to_string(),
                });

                if let Some(limit) = max_chunks {
                    if chunks.len() >= limit {
                        break;
                    }
                }
            }
        }

        if let Some(muxer) = current_muxer.as_mut() {
            let packet = packet.with_time_base(ac_ffmpeg::time::TimeBase::MICROSECONDS);
            muxer.push(packet).map_err(|err| anyhow!(err.to_string()))?;
        }
    }

    if let Some(mut muxer) = current_muxer.take() {
        let _ = muxer.flush();
        let _ = muxer.close();
    }
    if let (Some(index), Some(timing)) = (current_index.take(), current_timing.take()) {
        chunks.push(TsChunk {
            index,
            path: chunk_path(output_dir, index),
            timing,
        });
    }

    Ok(TsChunkManifest {
        output_dir: output_dir.to_path_buf(),
        chunks,
    })
}

pub fn hash_ts_chunks(manifest: &TsChunkManifest) -> Result<HashedTsChunkManifest> {
    let mut ordered = manifest.chunks.clone();
    ordered.sort_by_key(|chunk| chunk.index);

    let mut hashes = Vec::with_capacity(ordered.len());
    let mut chunks = Vec::with_capacity(ordered.len());
    for chunk in ordered {
        let hash = hash_file_blake3(&chunk.path)?;
        hashes.push(hash.clone());
        chunks.push(HashedTsChunk {
            index: chunk.index,
            path: chunk.path.clone(),
            timing: chunk.timing.clone(),
            hash,
        });
    }

    let merkle_root = merkle_root_from_hashes(&hashes)?;
    Ok(HashedTsChunkManifest {
        output_dir: manifest.output_dir.clone(),
        chunks,
        merkle_root,
    })
}

pub fn build_manifest_body_for_chunks(
    stream_id: StreamId,
    epoch_id: impl Into<String>,
    chunk_duration_ms: u64,
    chunk_start_index: u64,
    encoder_profile_id: impl Into<String>,
    created_unix_ms: u64,
    metadata: Vec<StreamMetadata>,
    chunk_hashes: &[String],
) -> Result<ManifestBody> {
    let merkle_root = merkle_root_from_hashes(chunk_hashes)?;
    Ok(ManifestBody {
        stream_id,
        epoch_id: epoch_id.into(),
        chunk_duration_ms,
        total_chunks: chunk_hashes.len() as u64,
        chunk_start_index,
        encoder_profile_id: encoder_profile_id.into(),
        merkle_root,
        created_unix_ms,
        metadata,
        chunk_hashes: chunk_hashes.to_vec(),
        variants: None,
    })
}

pub fn manifest_for_ts_chunks(
    stream_id: StreamId,
    epoch_id: impl Into<String>,
    chunk_duration_ms: u64,
    chunk_start_index: u64,
    encoder_profile_id: impl Into<String>,
    created_unix_ms: u64,
    metadata: Vec<StreamMetadata>,
    manifest: &TsChunkManifest,
) -> Result<(ManifestBody, HashedTsChunkManifest)> {
    let hashed = hash_ts_chunks(manifest)?;
    let chunk_hashes = hashed
        .chunks
        .iter()
        .map(|chunk| chunk.hash.clone())
        .collect::<Vec<_>>();
    let body = build_manifest_body_for_chunks(
        stream_id,
        epoch_id,
        chunk_duration_ms,
        chunk_start_index,
        encoder_profile_id,
        created_unix_ms,
        metadata,
        &chunk_hashes,
    )?;
    Ok((body, hashed))
}

pub fn chunk_stream_ffmpeg_live<T: Read, F: FnMut(TsChunk) -> Result<()>>(
    stream: T,
    output_dir: &Path,
    chunk_duration_ms: u64,
    max_chunks: Option<usize>,
    mut on_chunk: F,
) -> Result<()> {
    fs::create_dir_all(output_dir)
        .with_context(|| format!("failed to create {}", output_dir.display()))?;

    let io = IO::from_read_stream(stream);
    let demuxer = Demuxer::builder()
        .build(io)
        .map_err(|err| anyhow!(err.to_string()))?;
    let demuxer = demuxer
        .find_stream_info(Some(Duration::from_secs(2)))
        .map_err(|(_, err)| anyhow!(err.to_string()))?;

    let stream_info = demuxer
        .streams()
        .iter()
        .map(|stream| (stream.codec_parameters(), stream.time_base()))
        .collect::<Vec<_>>();

    let mut demuxer = demuxer.into_demuxer();
    let chunk_duration_micros = chunk_duration_ms as i64 * 1000;

    let mut current_index: Option<u64> = None;
    let mut current_muxer: Option<Muxer<std::fs::File>> = None;
    let mut current_timing: Option<ChunkTiming> = None;
    let mut emitted = 0usize;

    loop {
        let Some(packet) = demuxer.take().map_err(|err| anyhow!(err.to_string()))? else {
            break;
        };

        let ts = packet
            .pts()
            .as_micros()
            .or_else(|| packet.dts().as_micros());

        let chunk_index = ts
            .and_then(|micros| {
                if micros < 0 {
                    None
                } else {
                    Some((micros / chunk_duration_micros) as u64)
                }
            })
            .or(current_index);

        if let Some(index) = chunk_index {
            if current_index != Some(index) {
                if let Some(mut muxer) = current_muxer.take() {
                    muxer.flush().map_err(|err| anyhow!(err.to_string()))?;
                    let _ = muxer.close();
                }
                if let (Some(prev_index), Some(timing)) =
                    (current_index.take(), current_timing.take())
                {
                    let chunk = TsChunk {
                        index: prev_index,
                        path: chunk_path(output_dir, prev_index),
                        timing,
                    };
                    on_chunk(chunk)?;
                    emitted += 1;
                    if let Some(limit) = max_chunks {
                        if emitted >= limit {
                            return Ok(());
                        }
                    }
                }

                let path = chunk_path(output_dir, index);
                let file = std::fs::File::create(&path)
                    .with_context(|| format!("failed to create {}", path.display()))?;
                let io = IO::from_write_stream(file);
                let mut builder = Muxer::builder();
                for (params, _) in &stream_info {
                    builder
                        .add_stream(params)
                        .map_err(|err| anyhow!(err.to_string()))?;
                }
                for (stream, (_, tb)) in builder.streams_mut().iter_mut().zip(stream_info.iter()) {
                    stream.set_time_base(*tb);
                }
                let format = OutputFormat::find_by_name("mpegts")
                    .ok_or_else(|| anyhow!("mpegts format not found"))?;
                let muxer = builder
                    .interleaved(true)
                    .build(io, format)
                    .map_err(|err| anyhow!(err.to_string()))?;

                current_muxer = Some(muxer);
                current_index = Some(index);
                current_timing = Some(ChunkTiming {
                    chunk_index: index,
                    chunk_start_27mhz: ts.map(|micros| (micros as u64) * 27),
                    chunk_duration_27mhz: chunk_duration_ms * 27_000,
                    utc_start_unix: None,
                    sync_status: "pts".to_string(),
                });
            }
        }

        if let Some(muxer) = current_muxer.as_mut() {
            let packet = packet.with_time_base(ac_ffmpeg::time::TimeBase::MICROSECONDS);
            muxer.push(packet).map_err(|err| anyhow!(err.to_string()))?;
        }
    }

    if let Some(mut muxer) = current_muxer.take() {
        let _ = muxer.flush();
        let _ = muxer.close();
    }
    if let (Some(index), Some(timing)) = (current_index.take(), current_timing.take()) {
        let chunk = TsChunk {
            index,
            path: chunk_path(output_dir, index),
            timing,
        };
        on_chunk(chunk)?;
    }

    Ok(())
}

fn segment_format_arg(format: &ChunkFormat) -> &'static str {
    match format {
        ChunkFormat::Fmp4 => "mp4",
        ChunkFormat::MpegTs => "mpegts",
        ChunkFormat::Matroska => "matroska",
    }
}

pub fn ffmpeg_profile_args(profile: &DeterminismProfile) -> Vec<String> {
    let mut args = Vec::new();
    if !profile.encoder.is_empty() {
        args.push("-c:v".to_string());
        args.push(profile.encoder.clone());
    }
    for arg in &profile.encoder_args {
        args.push(arg.clone());
    }
    args
}

pub fn deterministic_h264_profile() -> DeterminismProfile {
    DeterminismProfile {
        name: "deterministic-h264-aac".to_string(),
        description: "Single-threaded H.264 + AAC with fixed GOP and bitexact flags".to_string(),
        encoder: "libx264".to_string(),
        encoder_args: vec![
            "-c:a".to_string(),
            "aac".to_string(),
            "-b:a".to_string(),
            "128k".to_string(),
            "-ac".to_string(),
            "2".to_string(),
            "-ar".to_string(),
            "48000".to_string(),
            "-pix_fmt".to_string(),
            "yuv420p".to_string(),
            "-g".to_string(),
            "60".to_string(),
            "-keyint_min".to_string(),
            "60".to_string(),
            "-sc_threshold".to_string(),
            "0".to_string(),
            "-bf".to_string(),
            "0".to_string(),
            "-threads".to_string(),
            "1".to_string(),
            "-fflags".to_string(),
            "+bitexact".to_string(),
            "-flags:v".to_string(),
            "+bitexact".to_string(),
            "-flags:a".to_string(),
            "+bitexact".to_string(),
        ],
        chunk_duration_ms: 2000,
    }
}

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

    fn ts_packet_with_pcr(pid: u16, cc: u8, pcr_27mhz: u64) -> [u8; ec_ts::TS_PACKET_SIZE] {
        // Match ec_ts parser expectations.
        let base = pcr_27mhz / 300;
        let ext = pcr_27mhz % 300;
        let mut pcr = [0u8; 6];
        pcr[0] = ((base >> 25) & 0xFF) as u8;
        pcr[1] = ((base >> 17) & 0xFF) as u8;
        pcr[2] = ((base >> 9) & 0xFF) as u8;
        pcr[3] = ((base >> 1) & 0xFF) as u8;
        pcr[4] = (((base & 0x1) << 7) as u8) | 0x7E | (((ext >> 8) & 0x1) as u8);
        pcr[5] = (ext & 0xFF) as u8;

        let mut data = [0u8; ec_ts::TS_PACKET_SIZE];
        data[0] = 0x47;
        data[1] = ((pid >> 8) as u8) & 0x1F;
        data[2] = (pid & 0xFF) as u8;
        data[3] = (2 << 4) | (cc & 0x0F); // adaptation only
        data[4] = 7;
        data[5] = 0x10;
        data[6..12].copy_from_slice(&pcr);
        data
    }

    #[test]
    fn segment_format_mapping_is_correct() {
        assert_eq!(segment_format_arg(&ChunkFormat::Fmp4), "mp4");
        assert_eq!(segment_format_arg(&ChunkFormat::MpegTs), "mpegts");
        assert_eq!(segment_format_arg(&ChunkFormat::Matroska), "matroska");
    }

    #[test]
    fn deterministic_profile_args_are_single_threaded_and_bitexact() {
        let profile = deterministic_h264_profile();
        let args = ffmpeg_profile_args(&profile);
        assert!(args.iter().any(|a| a == "-threads"));
        assert!(args.iter().any(|a| a == "1"));
        assert!(args.iter().any(|a| a == "+bitexact"));
        assert!(args.iter().any(|a| a == "libx264"));
    }

    #[test]
    fn hash_file_blake3_matches_direct_hash() {
        let dir = std::env::temp_dir().join(format!("ec-chopper-hash-{}", std::process::id()));
        let _ = fs::create_dir_all(&dir);
        let path = dir.join("x.bin");
        fs::write(&path, b"hello").unwrap();
        let h = hash_file_blake3(&path).unwrap();
        assert_eq!(h, blake3::hash(b"hello").to_hex().to_string());
        let _ = fs::remove_file(&path);
    }

    #[test]
    fn chunk_ts_stream_emits_expected_chunk_indices() {
        let chunk_ms = 1000u64;
        let dir = std::env::temp_dir().join(format!("ec-chopper-chunks-{}", std::process::id()));
        let _ = fs::remove_dir_all(&dir);
        fs::create_dir_all(&dir).unwrap();

        let mut bytes = Vec::new();
        bytes.extend_from_slice(&ts_packet_with_pcr(0x0100, 0, 0));
        bytes.extend_from_slice(&ts_packet_with_pcr(0x0100, 1, 27_000_000));
        bytes.extend_from_slice(&ts_packet_with_pcr(0x0100, 2, 54_000_000));

        let manifest = chunk_ts_stream(Cursor::new(bytes), &dir, chunk_ms, None).unwrap();
        let indices = manifest.chunks.iter().map(|c| c.index).collect::<Vec<_>>();
        assert_eq!(indices, vec![0, 1, 2]);
        for chunk in &manifest.chunks {
            let data = fs::read(&chunk.path).unwrap();
            assert_eq!(data.len() % ec_ts::TS_PACKET_SIZE, 0);
        }

        let _ = fs::remove_dir_all(&dir);
    }

    #[test]
    fn hashed_manifest_merkle_root_matches_core() {
        let dir = std::env::temp_dir().join(format!("ec-chopper-merkle-{}", std::process::id()));
        let _ = fs::remove_dir_all(&dir);
        fs::create_dir_all(&dir).unwrap();

        let mut bytes = Vec::new();
        bytes.extend_from_slice(&ts_packet_with_pcr(0x0100, 0, 0));
        bytes.extend_from_slice(&ts_packet_with_pcr(0x0100, 1, 27_000_000));
        let manifest = chunk_ts_stream(Cursor::new(bytes), &dir, 1000, None).unwrap();
        let hashed = hash_ts_chunks(&manifest).unwrap();
        let hashes = hashed
            .chunks
            .iter()
            .map(|c| c.hash.clone())
            .collect::<Vec<_>>();
        let expected = ec_core::merkle_root_from_hashes(&hashes).unwrap();
        assert_eq!(hashed.merkle_root, expected);

        let _ = fs::remove_dir_all(&dir);
    }
}