libfreemkv/src/labels/pixelogic.rs

//! Pixelogic — `bluray_project.bin`
//!
//! Binary file with embedded UTF-8 token strings in STN order per
//! playlist section. Most common format (5/10 test discs).
//!
//! Token format: `{lang}_{codec?}_{purpose?}_{region?}_`

use super::{LabelPurpose, LabelQualifier, StreamLabel, StreamLabelType, text, vocab};
use crate::sector::SectorReader;
use crate::udf::UdfFs;

/// Known audio codec tokens
const AUDIO_CODECS: &[&str] = &["MLP", "AC3", "DTS", "DDL", "WAV", "AC"];
/// Known region tokens
const REGIONS: &[&str] = &[
    "US", "UK", "CF", "PF", "CS", "LS", "BP", "PP", "SM", "TM", "CAN", "DUM", "FLE",
];

pub fn detect(udf: &UdfFs) -> bool {
    super::jar_file_exists(udf, "bluray_project.bin")
}

pub fn parse(reader: &mut dyn SectorReader, udf: &UdfFs) -> Option<Vec<StreamLabel>> {
    let data = super::read_jar_file(reader, udf, "bluray_project.bin")?;
    // min_len=4 matches the prior local extract_strings impl. The token
    // grammar is `{lang3}_{codec?}_{purpose?}_{region?}_` so the
    // shortest meaningful run is 4 chars (lang + underscore).
    let strings = text::extract_ascii_strings(&data, 4);

    let mut labels = Vec::new();
    let mut in_feature = false;
    let mut audio_num: u16 = 0;
    let mut sub_num: u16 = 0;

    for s in &strings {
        // Detect feature section start
        if s.starts_with("FPL_") || s.starts_with("SEG_MainFeature") {
            if in_feature {
                break;
            }
            in_feature = true;
            audio_num = 0;
            sub_num = 0;
            continue;
        }

        // Detect section end
        if in_feature && (s.starts_with("SEG_") || s.starts_with("SF_") || s.starts_with("FPL_")) {
            break;
        }

        if !in_feature {
            continue;
        }

        if let Some(label) = parse_token(s) {
            match label.stream_type {
                StreamLabelType::Audio => {
                    audio_num += 1;
                    labels.push(StreamLabel {
                        stream_number: audio_num,
                        ..label
                    });
                }
                StreamLabelType::Subtitle => {
                    sub_num += 1;
                    labels.push(StreamLabel {
                        stream_number: sub_num,
                        ..label
                    });
                }
            }
        }
    }

    if labels.is_empty() {
        return None;
    }
    Some(labels)
}

fn parse_token(s: &str) -> Option<StreamLabel> {
    let clean = s.trim().trim_start_matches('\t').trim_end_matches('_');
    let parts: Vec<&str> = clean.split('_').collect();
    if parts.len() < 2 {
        return None;
    }

    let lang = parts[0];
    if lang.len() != 3 || !lang.chars().all(|c| c.is_ascii_lowercase()) {
        return None;
    }

    let mut codec = String::new();
    let mut purpose = LabelPurpose::Normal;
    let mut qualifier = LabelQualifier::None;
    let mut variant = String::new();
    let mut is_subtitle = false;
    let mut is_audio = false;

    for &part in &parts[1..] {
        if part.is_empty() {
            continue;
        }
        if AUDIO_CODECS.contains(&part) {
            codec = vocab::codec(part).to_string();
            is_audio = true;
        } else if part == "ADES" {
            purpose = LabelPurpose::Descriptive;
            is_audio = true;
        } else if part == "ACOM" {
            purpose = LabelPurpose::Commentary;
            is_audio = true;
        } else if part == "ADLG" || part == "ATRI" {
            is_audio = true;
        } else if part == "SDH" {
            qualifier = LabelQualifier::Sdh;
            is_subtitle = true;
        } else if part == "SDLG" {
            is_subtitle = true;
        } else if part == "SCOM" {
            purpose = LabelPurpose::Commentary;
            is_subtitle = true;
        } else if part == "STRI" || part == "TXT" {
            is_subtitle = true;
        } else if part == "FOR" {
            qualifier = LabelQualifier::Forced;
        } else if REGIONS.contains(&part) {
            variant = part.to_string();
        } else if part.starts_with("PGStream") {
            is_subtitle = true;
        } else {
            // Unknown token component — skip this single part rather
            // than discarding the entire stream record. Pre-refactor
            // behavior was `return None` here, which silently dropped
            // any stream containing a single uncatalogued token (e.g.
            // a new codec ID or framework variant). Better to surface
            // what we know than discard a whole stream over one part.
            tracing::debug!(part = %part, "pixelogic: unrecognized token component, skipping");
        }
    }

    if !is_audio && !is_subtitle {
        return None;
    }

    let stream_type = if is_subtitle {
        StreamLabelType::Subtitle
    } else {
        StreamLabelType::Audio
    };

    Some(StreamLabel {
        stream_number: 0,
        stream_type,
        language: lang.to_string(),
        name: String::new(),
        purpose,
        qualifier,
        codec_hint: codec,
        variant,
    })
}

// extract_strings removed — replaced by super::text::extract_ascii_strings(data, 4).

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

    #[test]
    fn parse_token_basic_audio() {
        let l = parse_token("eng_MLP_").unwrap();
        assert_eq!(l.stream_type, StreamLabelType::Audio);
        assert_eq!(l.language, "eng");
        assert_eq!(l.codec_hint, "TrueHD");
        assert_eq!(l.purpose, LabelPurpose::Normal);
    }

    #[test]
    fn parse_token_basic_subtitle_sdh() {
        let l = parse_token("eng_SDH_").unwrap();
        assert_eq!(l.stream_type, StreamLabelType::Subtitle);
        assert_eq!(l.language, "eng");
        assert_eq!(l.qualifier, LabelQualifier::Sdh);
    }

    #[test]
    fn parse_token_commentary() {
        let l = parse_token("eng_MLP_ACOM_").unwrap();
        assert_eq!(l.stream_type, StreamLabelType::Audio);
        assert_eq!(l.purpose, LabelPurpose::Commentary);
    }

    #[test]
    fn parse_token_descriptive() {
        let l = parse_token("eng_AC3_ADES_").unwrap();
        assert_eq!(l.purpose, LabelPurpose::Descriptive);
    }

    #[test]
    fn parse_token_with_region() {
        let l = parse_token("eng_MLP_US_").unwrap();
        assert_eq!(l.language, "eng");
        assert_eq!(l.variant, "US");
    }

    #[test]
    fn parse_token_unknown_component_does_not_kill_stream() {
        // Regression: pre-refactor, an unrecognized token part returned
        // None for the whole stream, silently dropping it. New
        // behavior: skip the unknown part, surface what we know.
        let l = parse_token("eng_MLP_FUTUREFLAG_FOR_").unwrap();
        assert_eq!(l.stream_type, StreamLabelType::Audio);
        assert_eq!(l.language, "eng");
        assert_eq!(l.codec_hint, "TrueHD");
        assert_eq!(l.qualifier, LabelQualifier::Forced);
    }

    #[test]
    fn parse_token_no_audio_or_subtitle_signal_returns_none() {
        // A token that has only a language and an unknown part with
        // no audio/subtitle classifier should still return None —
        // there's no way to file it as a stream.
        assert!(parse_token("eng_UNKNOWN_").is_none());
    }

    #[test]
    fn parse_token_rejects_non_lang_prefix() {
        assert!(parse_token("XX_MLP_").is_none());
        assert!(parse_token("ENG_MLP_").is_none()); // uppercase not accepted as ISO 639-2
    }
}