//! lib/edge/scan.ts (SegmentScanner, scanOverviewText), lib/files/aggregator.ts
//! and lib/edge/range_indexer.ts (RangeIndexer, chunkOf, candidatesOf), in the
//! same order of operations, so the outputs can be compared one to one.

use crate::codec::{encode_chunk, ChunkFile};
use crate::js::{self, sha1_hex};
use crate::names::{self, is_random_file, JudgedFile, Release, Rules, Verdict};
use rustc_hash::{FxHashMap, FxHashSet};
use std::rc::Rc;

pub static mut PROF: [u64; 8] = [0; 8];

pub struct FileMeta {
    pub file_key: String,
    pub name: String,
    pub poster: String,
    pub subject: String,
    pub total_parts: u32,
    pub groups: Vec<String>,
    pub release: Release,
}

pub struct Seg {
    pub file: Rc<FileMeta>,
    pub number: u32,
    pub message_id: String,
    pub bytes: i64,
    pub article: i64,
    pub posted_at: Option<i64>,
}

pub struct ReleaseChunk {
    pub key: String,
    pub upload: usize,
    pub name: String,
    pub source: &'static str,
    pub file_total: Option<i64>,
    pub poster: String,
    pub groups: Vec<String>,
    pub posted_at: Option<i64>,
    pub posted_last: Option<i64>,
    pub files: usize,
    pub segments: usize,
    pub bytes: i64,
    pub first_article: i64,
    pub last_article: i64,
    pub readable: bool,
    pub has_par2: bool,
    pub payload: Vec<u8>,
    /// The first files' subjects (at most SUBJECTS): edge-bench's --releases dump for the grouping sweeps.
    pub subjects: Vec<String>,
}

pub const SUBJECTS: usize = 3;

pub struct Candidate {
    pub release_key: String,
    pub upload: usize,
    pub kind: &'static str,
    pub message_id: String,
    pub file: String,
}

pub struct Fragment {
    pub file_key: String,
    pub name: String,
    pub poster: String,
    pub subject: String,
    pub total_parts: u32,
    pub groups: Vec<String>,
    pub release: Release,
    pub posted_at: Option<i64>,
    pub segments: Vec<(u32, String, i64, i64)>,
}

#[derive(Default)]
pub struct Batch {
    pub from: i64,
    pub next: i64,
    pub headers: u64,
    pub releases: Vec<ReleaseChunk>,
    pub samples: Vec<(ReleaseChunk, &'static str, String)>,
    pub candidates: Vec<Candidate>,
    /// (rule, key) → (articles, files)
    pub counts: Vec<(&'static str, String, u64, u64)>,
    pub fragments: Vec<Fragment>,
}

struct Counter {
    index: usize,
    length: usize,
    segment: i64,
    total: i64,
}

/// The last "(k/N)" after `after` (anywhere when None: JS -1), scanning back from the end (findCounter).
fn find_counter(subject: &[u8], after: Option<usize>) -> Option<Counter> {
    let mut open = subject.len();
    loop {
        // lastIndexOf('(', open - 1): at most open - 1.
        if open == 0 {
            return None;
        }
        open = subject[..open].iter().rposition(|&c| c == b'(')?;
        if after.is_some_and(|a| open <= a) {
            return None;
        }
        let mut i = open + 1;
        let mut segment: i64 = 0;
        let mut digits = 0;
        while let Some(c) = subject.get(i).filter(|c| c.is_ascii_digit()) {
            segment = segment * 10 + (c - b'0') as i64;
            digits += 1;
            i += 1;
        }
        if digits == 0 || subject.get(i) != Some(&b'/') {
            continue;
        }
        i += 1;
        let mut total: i64 = 0;
        digits = 0;
        while let Some(c) = subject.get(i).filter(|c| c.is_ascii_digit()) {
            total = total * 10 + (c - b'0') as i64;
            digits += 1;
            i += 1;
        }
        if digits == 0 || subject.get(i) != Some(&b')') {
            continue;
        }
        return Some(Counter { index: open, length: i + 1 - open, segment, total });
    }
}

fn xref_groups(xref: &str, group: &str) -> Vec<String> {
    let mut groups = Vec::new();
    for token in js::split_spaces(js::trim(xref)).into_iter().skip(1) {
        if let Some(colon) = token.rfind(':') {
            if colon > 0 {
                groups.push(token[..colon].to_string());
            }
        }
    }
    if groups.is_empty() {
        groups.push(group.to_string());
    }
    groups
}

#[derive(Default)]
struct Scanner {
    files: FxHashMap<String, Option<Rc<FileMeta>>>,
    key: String,
}

impl Scanner {
    fn owner<'a>(&self, xref: &'a str, group: &'a str, priorities: &FxHashMap<String, u32>) -> &'a str {
        let b = xref.as_bytes();
        let Some(mut at) = xref.find(' ') else { return group };
        let mut owner: Option<&str> = None;
        let mut best = u32::MAX;
        loop {
            while b.get(at) == Some(&b' ') {
                at += 1;
            }
            if at >= b.len() {
                break;
            }
            let end = xref[at..].find(' ').map(|i| i + at);
            // lastIndexOf(':', end ?? length): a colon at or before `end`.
            let limit = end.unwrap_or(b.len());
            let colon = xref[..limit.min(b.len())].rfind(':');
            if let Some(colon) = colon.filter(|&c| c > at) {
                let name = &xref[at..colon];
                if let Some(&p) = priorities.get(name) {
                    if p < best {
                        best = p;
                        owner = Some(name);
                    }
                }
            }
            match end {
                Some(e) => at = e,
                None => break,
            }
        }
        owner.unwrap_or(group)
    }

    #[allow(clippy::too_many_arguments)]
    fn segment(&mut self, article: i64, subject: &str, from: &str, date: &str, message_id: &str, bytes: &str, xref: &str, group: &str) -> Option<Seg> {
        if subject.is_empty() || message_id.is_empty() {
            return None;
        }
        let sb = subject.as_bytes();
        // After the last quote; without one, anywhere (unquoted_name finds the file name).
        let name_end = subject.rfind('"');
        let counter = find_counter(sb, name_end)?;
        self.key.clear();
        self.key.push_str(from);
        self.key.push('\u{1}');
        self.key.push_str(&subject[..counter.index]);
        self.key.push('\u{0}');
        self.key.push_str(&subject[counter.index + counter.length..]);
        let file = match self.files.get(self.key.as_str()) {
            Some(f) => f.clone(),
            None => {
                let f = describe(subject, name_end, &counter, from, xref, group).map(Rc::new);
                self.files.insert(self.key.clone(), f.clone());
                f
            }
        };
        let file = file?;
        if counter.segment < 1 || counter.segment > file.total_parts as i64 {
            return None;
        }
        let id = if message_id.starts_with('<') { message_id.get(1..message_id.len().saturating_sub(1)).unwrap_or("") } else { message_id };
        Some(Seg {
            number: counter.segment as u32,
            message_id: id.to_string(),
            bytes: js::parse_int(bytes).unwrap_or(0),
            article,
            posted_at: js::parse_date(date),
            file,
        })
    }
}

fn describe(subject: &str, name_end: Option<usize>, counter: &Counter, from: &str, xref: &str, group: &str) -> Option<FileMeta> {
    let quoted = match name_end {
        Some(end) if end > 0 => subject[..end].rfind('"').map(|start| subject[start + 1..end].to_string()),
        _ => None,
    };
    let name = match quoted {
        Some(name) => name_beside_quotes(&name, &subject[..counter.index]).unwrap_or(name),
        None => unquoted_name(&subject[..counter.index])?,
    };
    let name = name.as_str();
    if name.is_empty() || counter.total < 1 {
        return None;
    }
    let joined = format!("{}{}", &subject[..counter.index], &subject[counter.index + counter.length..]);
    let base = js::trim(&js::collapse_spaces(&joined)).to_string();
    let file_key = sha1_hex(&format!("{from}\n{base}\n{}", counter.total));
    let release = names::release_identity(from, &base, name);
    Some(FileMeta {
        file_key,
        name: name.to_string(),
        poster: from.to_string(),
        subject: base,
        total_parts: counter.total as u32,
        groups: xref_groups(xref, group),
        release,
    })
}

/// EXTENSION: /[^.\s]\.[A-Za-z0-9]{2,4}$/
fn has_extension(s: &str) -> bool {
    let Some(dot) = s.rfind('.') else { return false };
    let ext = &s.as_bytes()[dot + 1..];
    if !(2..=4).contains(&ext.len()) || !ext.iter().all(|c| c.is_ascii_alphanumeric()) {
        return false;
    }
    s[..dot].chars().last().is_some_and(|c| c != '.' && !js::is_space(c))
}

/// The first / - \d{1,3} - / in `text`: the index of its " - ".
fn first_track(text: &str) -> Option<usize> {
    let b = text.as_bytes();
    let mut from = 0;
    while let Some(i) = text[from..].find(" - ").map(|i| i + from) {
        let digits = b[i + 3..].iter().take_while(|c| c.is_ascii_digit()).count();
        if (1..=3).contains(&digits) && b[i + 3 + digits..].starts_with(b" - ") {
            return Some(i);
        }
        from = i + 1;
    }
    None
}

/// nameBesideQuotes (lib/headers/subject.ts): a file name elsewhere when the quoted text has no extension.
pub fn name_beside_quotes(quoted: &str, before_counter: &str) -> Option<String> {
    if has_extension(quoted) {
        return None;
    }
    // A stray quote took the last pair: the last quoted part that is a file name.
    let mut named = None;
    let mut rest = before_counter;
    while let Some(open) = rest.find('"') {
        let Some(close) = rest[open + 1..].find('"') else { break };
        let part = &rest[open + 1..open + 1 + close];
        if has_extension(part) {
            named = Some(part);
        }
        rest = &rest[open + 1 + close + 1..];
    }
    if let Some(part) = named {
        return Some(part.to_string());
    }
    // .replace(/"[^"]*"/g, ' ')
    let mut text = String::with_capacity(before_counter.len());
    let mut rest = before_counter;
    while let Some(open) = rest.find('"') {
        match rest[open + 1..].find('"') {
            Some(close) => {
                text.push_str(&rest[..open]);
                text.push(' ');
                rest = &rest[open + 1 + close + 1..];
            }
            None => break,
        }
    }
    text.push_str(rest);
    unquoted_name(&text).filter(|n| has_extension(n))
}

/// unquotedName (lib/headers/subject.ts): the file name of a subject without a quoted one, from the text before its counter.
/// /\.(jpe?g|png|gif|bmp|webp|tiff?)$/i
fn is_image_name(name: &str) -> bool {
    let lower = name.to_ascii_lowercase();
    [".jpg", ".jpeg", ".png", ".gif", ".bmp", ".webp", ".tif", ".tiff"].iter().any(|e| lower.ends_with(e))
}

/// DATE_ONLY (lib/headers/subject.ts): a file name that is a date alone ("15_07_2015.rar").
fn date_only(name: &str) -> bool {
    static DATE_ONLY: std::sync::LazyLock<regex::Regex> = std::sync::LazyLock::new(|| {
        regex::Regex::new(r"^(?:[0-9]{1,2}[-_.][0-9]{1,2}[-_.](?:19|20)[0-9]{2}|(?:19|20)[0-9]{2}[-_.][0-9]{1,2}[-_.][0-9]{1,2})\.[A-Za-z0-9]{2,4}$").unwrap()
    });
    DATE_ONLY.is_match(name)
}

pub fn unquoted_name(before_counter: &str) -> Option<String> {
    let mut text = before_counter.trim_end_matches(js::is_space);
    if text.len() >= 4 && text.is_char_boundary(text.len() - 4) && text[text.len() - 4..].eq_ignore_ascii_case("yenc") {
        text = text[..text.len() - 4].trim_end_matches(js::is_space);
    }
    if let Some(quote) = text.find('"') {
        if text[quote + 1..].contains('"') {
            return None;
        }
        let before = &text[..quote];
        if let Some(bracket) = before.rfind('[') {
            let inside = js::trim(&before[bracket + 1..]);
            // replace(/^\d+\/\d+ +/, '')
            let b = inside.as_bytes();
            let mut i = 0;
            while i < b.len() && b[i].is_ascii_digit() {
                i += 1;
            }
            let mut stripped = inside;
            if i > 0 && b.get(i) == Some(&b'/') {
                let mut j = i + 1;
                while j < b.len() && b[j].is_ascii_digit() {
                    j += 1;
                }
                if j > i + 1 && b.get(j) == Some(&b' ') {
                    while j < b.len() && b[j] == b' ' {
                        j += 1;
                    }
                    stripped = &inside[j..];
                }
            }
            if has_extension(stripped) {
                return Some(stripped.to_string());
            }
        }
        let word = &before[before.rfind(' ').map_or(0, |i| i + 1)..];
        return has_extension(word).then(|| word.to_string());
    }
    // A single-quoted name at the end: /'([^']*[^.\s']\.[A-Za-z0-9]{2,4})'$/
    if let Some(inner) = text.strip_suffix('\'') {
        if let Some(open) = inner.rfind('\'') {
            let part = &inner[open + 1..];
            if has_extension(part) {
                return Some(part.to_string());
            }
        }
    }
    if has_extension(text) {
        let bracket = text.rfind("] ").map_or(0, |i| i + 2);
        // A track or part number (/ - \d{1,3} - /): the name starts there; else after the last " - ".
        let dash = first_track(text).or_else(|| text.rfind(" - ")).map_or(0, |i| i + 3);
        // Or after an arrow ("… -> Exclusive-tgirls_000000-lg.jpg").
        let arrow = text.rfind("-> ").map_or(0, |i| i + 3);
        let cut = bracket.max(dash).max(arrow);
        // A date alone after the cut ("… [ettv] 15_07_2015.rar"): the whole text is the name.
        let name = if date_only(js::trim(&text[cut..])) { js::trim(text) } else { js::trim(&text[cut..]) };
        // An image after numbered text without a separator: its last word ("<abm> … AB: part2 0573-1002 043.jpg").
        // Not an index alone ("Teen Tease Self Shooter sad1 (10).jpg").
        if cut == 0 && is_image_name(name) && name.contains(' ') {
            let space = name.rfind(' ').unwrap();
            let last = &name[space + 1..];
            if name[..space].trim_end_matches(js::is_space).ends_with(|c: char| c.is_ascii_digit()) && !last.starts_with('(') {
                return Some(last.to_string());
            }
        }
        // Ending in a host is no file name: the one in brackets or a word follows.
        if !is_host(name) {
            return (!name.is_empty() && has_extension(name)).then(|| name.to_string());
        }
    }
    // A name in brackets: the last /\[([^[\]]*[^.\s[\]]\.[A-Za-z0-9]{2,4})\]/.
    let mut bracketed = None;
    for (open, _) in text.match_indices('[') {
        let inside = &text[open + 1..];
        let Some(close) = inside.find(']') else { break };
        let part = &inside[..close];
        if !part.contains('[') && has_extension(part) {
            bracketed = Some(part);
        }
    }
    if let Some(part) = bracketed {
        return Some(part.to_string());
    }
    text.split(' ').find(|w| has_extension(w) && !is_host(w)).map(str::to_string)
}

/// /www\./i: a host ("www.libranews.nl"), whose ".nl" is no extension.
fn is_host(s: &str) -> bool {
    s.to_ascii_lowercase().contains("www.")
}

/// One line of an XOVER reply: number, subject, from, date, message-id, bytes, xref (scanOverviewText).
fn scan_overview_text(text: &str, mut line: impl FnMut(Option<i64>, &str, &str, &str, &str, &str, &str)) {
    let b = text.as_bytes();
    let mut start = 0;
    while start < b.len() {
        let end = memchr::memchr(b'\n', &b[start..]).map(|i| i + start).unwrap_or(b.len());
        let stop = if end > start && b[end - 1] == b'\r' { end - 1 } else { end };
        if stop > start {
            let l = &text[start..stop];
            let lb = l.as_bytes();
            let mut tabs = [usize::MAX; 9];
            let mut n = 0;
            for i in memchr::memchr_iter(b'\t', lb) {
                tabs[n] = i;
                n += 1;
                if n == 9 {
                    break;
                }
            }
            if n >= 5 {
                let field = |a: usize, b: usize| -> &str {
                    if a == usize::MAX {
                        ""
                    } else {
                        &l[a + 1..if b == usize::MAX { l.len() } else { b }]
                    }
                };
                let mut xref = if n >= 8 { field(tabs[7], tabs[8]) } else { "" };
                if let Some(rest) = xref.strip_prefix("Xref:") {
                    xref = rest.strip_prefix(' ').unwrap_or(rest);
                }
                line(js::parse_int(&l[..tabs[0]]), &l[tabs[0] + 1..tabs[1]], field(tabs[1], tabs[2]), field(tabs[2], tabs[3]), field(tabs[3], tabs[4]), field(tabs[5], tabs[6]), xref);
            }
        }
        start = end + 1;
    }
}

/// A re-upload's copy of a file is kept apart (FileAggregator, uploadGapMs).
pub const UPLOAD_GAP_MS: i64 = 3 * 60 * 60 * 1000;

struct OpenFile {
    parts: Vec<Seg>,
    seen: FxHashSet<u32>,
    total: u32,
    touched: u64,
    /// Posting times seen.
    earliest: Option<i64>,
    latest: Option<i64>,
}

impl OpenFile {
    fn distance(&self, t: Option<i64>) -> i64 {
        match (t, self.earliest, self.latest) {
            (Some(t), Some(e), Some(l)) => 0.max(e - t).max(t - l),
            _ => 0,
        }
    }
}

#[derive(Default)]
struct Aggregator {
    /// Per file key its open copies, oldest first.
    open: FxHashMap<String, Vec<OpenFile>>,
    batch: u64,
}

impl Aggregator {
    fn add(&mut self, segments: Vec<Seg>) -> Vec<Vec<Seg>> {
        self.batch += 1;
        let batch = self.batch;
        let mut touched: Vec<String> = Vec::new();
        let mut touched_set: FxHashSet<String> = FxHashSet::default();
        for s in segments {
            let key = s.file.file_key.clone();
            if !touched_set.contains(key.as_str()) {
                touched_set.insert(key.clone());
                touched.push(key.clone());
            }
            let copies = self.open.entry(key).or_default();
            let t = s.posted_at;
            // A copy lacking the part, the nearest in time.
            let mut chosen: Option<usize> = None;
            let mut best = i64::MAX;
            for (i, copy) in copies.iter().enumerate() {
                if copy.seen.contains(&s.number) {
                    continue;
                }
                let d = copy.distance(t);
                if d < best {
                    best = d;
                    chosen = Some(i);
                }
            }
            let index = match chosen {
                Some(i) => i,
                None => {
                    if let Some(near) = copies.iter_mut().find(|c| c.distance(t) <= UPLOAD_GAP_MS) {
                        near.touched = batch;
                        continue;
                    }
                    copies.push(OpenFile { parts: Vec::new(), seen: FxHashSet::default(), total: s.file.total_parts, touched: batch, earliest: None, latest: None });
                    copies.len() - 1
                }
            };
            let file = &mut copies[index];
            file.seen.insert(s.number);
            if let Some(t) = t {
                if file.earliest.is_none_or(|e| t < e) {
                    file.earliest = Some(t);
                }
                if file.latest.is_none_or(|l| t > l) {
                    file.latest = Some(t);
                }
            }
            file.touched = batch;
            file.parts.push(s);
        }
        let mut complete = Vec::new();
        for key in touched {
            let copies = self.open.get_mut(&key).unwrap();
            let mut i = 0;
            while i < copies.len() {
                if (copies[i].parts.len() as u32) < copies[i].total {
                    i += 1;
                    continue;
                }
                let mut f = copies.remove(i);
                f.parts.sort_by_key(|s| s.number);
                complete.push(f.parts);
            }
            if copies.is_empty() {
                self.open.remove(&key);
            }
        }
        complete
    }

    /// Files idle for `idle` batches (all when 0): their segments, per file key (its copies one after another).
    fn evict(&mut self, idle: u64) -> Vec<Vec<Seg>> {
        let batch = self.batch;
        let mut out = Vec::new();
        let keys: Vec<String> = self.open.keys().cloned().collect();
        for key in keys {
            let copies = self.open.get_mut(&key).unwrap();
            let mut gone: Vec<Seg> = Vec::new();
            let mut i = 0;
            while i < copies.len() {
                if idle > 0 && batch - copies[i].touched < idle {
                    i += 1;
                    continue;
                }
                gone.extend(copies.remove(i).parts);
            }
            if copies.is_empty() {
                self.open.remove(&key);
            }
            if !gone.is_empty() {
                out.push(gone);
            }
        }
        out
    }
}

/// uploadsOf: a key's files split where posting pauses for more than UPLOAD_GAP_MS after the latest article so far.
fn uploads_of(files: Vec<Vec<Seg>>) -> Vec<Vec<Vec<Seg>>> {
    if files.len() < 2 {
        return vec![files];
    }
    let first: Vec<Option<i64>> = files.iter().map(|f| posted_of(f)).collect();
    let last: Vec<Option<i64>> = files.iter().map(|f| f.iter().filter_map(|s| s.posted_at).max()).collect();
    let mut dated: Vec<usize> = (0..files.len()).filter(|&i| first[i].is_some()).collect();
    if dated.len() < 2 {
        return vec![files];
    }
    dated.sort_by_key(|&i| (first[i].unwrap(), i));
    let mut upload = vec![0usize; files.len()];
    let mut current = 0;
    let mut end = last[dated[0]].unwrap();
    for &i in &dated[1..] {
        if first[i].unwrap() - end > UPLOAD_GAP_MS {
            current += 1;
            end = last[i].unwrap();
        } else if last[i].unwrap() > end {
            end = last[i].unwrap();
        }
        upload[i] = current;
    }
    if current == 0 {
        return vec![files];
    }
    let mut out: Vec<Vec<Vec<Seg>>> = (0..=current).map(|_| Vec::new()).collect();
    for (i, f) in files.into_iter().enumerate() {
        out[upload[i]].push(f);
    }
    out
}

pub struct RangeIndexer {
    group: String,
    rules: Rules,
    start: i64,
    end: i64,
    priorities: FxHashMap<String, u32>,
    idle: u64,
    chunk_articles: i64,
    scanner: Scanner,
    aggregator: Aggregator,
    batch: Batch,
    counts: FxHashMap<(&'static str, String), (u64, u64)>,
    count_order: Vec<(&'static str, String)>,
    completed: FxHashMap<String, Vec<Vec<Seg>>>,
    completed_order: Vec<String>,
}

impl RangeIndexer {
    /// `resume_at`: where this worker starts (a range taken over midway); its first batch starts there.
    pub fn new(group: &str, start: i64, end: i64, resume_at: i64, rules: Rules, idle: u64) -> Self {
        RangeIndexer {
            group: group.to_string(),
            start,
            end,
            priorities: rules.priorities.clone(),
            rules,
            idle,
            chunk_articles: 0,
            scanner: Scanner::default(),
            aggregator: Aggregator::default(),
            batch: Batch { from: resume_at, next: resume_at, ..Default::default() },
            counts: FxHashMap::default(),
            count_order: Vec::new(),
            completed: FxHashMap::default(),
            completed_order: Vec::new(),
        }
    }

    pub fn add_text(&mut self, text: &str, next: i64) {
        let mut segments: Vec<Seg> = Vec::new();
        let mut crossposts: Vec<String> = Vec::new();
        let mut obfuscated = 0u64;
        let mut headers = 0u64;
        {
            let group = self.group.clone();
            let scanner = &mut self.scanner;
            let priorities = &self.priorities;
            scan_overview_text(text, |n, subject, from, date, message_id, bytes, xref| {
                let Some(n) = n else { return };
                if message_id.is_empty() {
                    return;
                }
                headers += 1;
                let owner = if xref.is_empty() { group.as_str() } else { scanner.owner(xref, &group, priorities) };
                if owner != group {
                    crossposts.push(owner.to_string());
                    return;
                }
                match scanner.segment(n, subject, from, date, message_id, bytes, xref, &group) {
                    Some(s) => segments.push(s),
                    None => obfuscated += 1,
                }
            });
        }
        self.batch.headers += headers;
        for owner in crossposts {
            self.count("crosspost", owner, 1, 0);
        }
        if obfuscated > 0 {
            self.count("obfuscated", String::new(), obfuscated, 0);
        }
        self.end_chunk(segments, next);
    }

    fn end_chunk(&mut self, segments: Vec<Seg>, next: i64) {
        let t = std::time::Instant::now();
        let done = self.aggregator.add(segments);
        unsafe { PROF[3] += t.elapsed().as_nanos() as u64; }
        self.files(done);
        if self.chunk_articles == 0 {
            self.chunk_articles = next - self.batch.from;
        }
        let t = std::time::Instant::now();
        let gone = self.aggregator.evict(self.idle);
        self.cut_off(gone, false);
        unsafe { PROF[4] += t.elapsed().as_nanos() as u64; }
        self.batch.next = next;
    }

    pub fn finish(&mut self) {
        let gone = self.aggregator.evict(0);
        self.cut_off(gone, true);
        self.batch.next = self.end + 1;
    }

    /// Files completed and fragments cut since the last take (RangeIndexer.pending).
    pub fn pending(&self) -> usize {
        self.batch.fragments.len() + self.completed.values().map(|l| l.len()).sum::<usize>()
    }

    pub fn take(&mut self) -> Batch {
        let t = std::time::Instant::now();
        self.judge_releases();
        unsafe { PROF[5] += t.elapsed().as_nanos() as u64; }
        self.scanner.files.clear();
        let next = self.batch.next;
        let mut out = std::mem::replace(&mut self.batch, Batch { from: next, next, ..Default::default() });
        for id in self.count_order.drain(..) {
            let (articles, files) = self.counts.remove(&id).unwrap();
            out.counts.push((id.0, id.1, articles, files));
        }
        out
    }

    fn files(&mut self, files: Vec<Vec<Seg>>) {
        for file in files {
            let key = release_key_of(&file[0]);
            match self.completed.get_mut(&key) {
                Some(list) => list.push(file),
                None => {
                    self.completed_order.push(key.clone());
                    self.completed.insert(key, vec![file]);
                }
            }
        }
    }

    fn judge_releases(&mut self) {
        let order = std::mem::take(&mut self.completed_order);
        let mut by_release = std::mem::take(&mut self.completed);
        for key in order {
            for (upload, list) in uploads_of(by_release.remove(&key).unwrap()).into_iter().enumerate() {
                let judged: Vec<JudgedFile> = list
                    .iter()
                    .map(|f| JudgedFile { name: &f[0].file.name, total_parts: f[0].file.total_parts, groups: &f[0].file.groups, first_message_id: &f[0].message_id })
                    .collect();
                match names::judge(&key, &judged, &self.rules) {
                    Verdict::Keep => {
                        let candidates = candidates_of(&key, &list, upload);
                        self.batch.releases.push(chunk_of(&key, &list, upload));
                        self.batch.candidates.extend(candidates);
                    }
                    Verdict::Drop { rule, key: rule_key, sample } => {
                        let segments: usize = list.iter().map(|f| f.len()).sum();
                        self.count(rule, rule_key.clone(), segments as u64, list.len() as u64);
                        if sample {
                            self.batch.samples.push((chunk_of(&key, &list, upload), rule, rule_key));
                        }
                    }
                }
            }
        }
    }

    fn cut_off(&mut self, files: Vec<Vec<Seg>>, at_end: bool) {
        let window = self.idle as i64 * self.chunk_articles.max(1);
        for list in files {
            if list.len() == 1 && is_random_file(&list[0].file.name) {
                let tool = names::upload_tool(&list[0].message_id);
                self.count("per-article", tool.to_string(), 1, 0);
                continue;
            }
            let min_part = list.iter().map(|s| s.number).min().unwrap();
            let max_part = list.iter().map(|s| s.number).max().unwrap();
            let first_article = list.iter().map(|s| s.article).min().unwrap();
            let cut_at_start = min_part > 1 && first_article < self.start + window;
            let cut_at_end = at_end && max_part < list[0].file.total_parts;
            if !cut_at_start && !cut_at_end {
                self.count("incomplete", String::new(), list.len() as u64, 1);
                continue;
            }
            let f = &list[0].file;
            let mut fragment = Fragment {
                file_key: f.file_key.clone(),
                name: f.name.clone(),
                poster: f.poster.clone(),
                subject: f.subject.clone(),
                total_parts: f.total_parts,
                groups: f.groups.clone(),
                release: f.release.clone(),
                posted_at: None,
                segments: Vec::with_capacity(list.len()),
            };
            for s in &list {
                fragment.segments.push((s.number, s.message_id.clone(), s.bytes, s.article));
                if let Some(t) = s.posted_at {
                    if fragment.posted_at.is_none_or(|p| t < p) {
                        fragment.posted_at = Some(t);
                    }
                }
            }
            self.batch.fragments.push(fragment);
        }
    }

    fn count(&mut self, rule: &'static str, key: String, articles: u64, files: u64) {
        match self.counts.get_mut(&(rule, key.clone())) {
            Some(c) => {
                c.0 += articles;
                c.1 += files;
            }
            None => {
                self.count_order.push((rule, key.clone()));
                self.counts.insert((rule, key), (articles, files));
            }
        }
    }
}

fn release_key_of(s: &Seg) -> String {
    // A named file always has a release (releaseIdentity isn't null unless weak).
    s.file.release.key.clone()
}

fn posted_of(segments: &[Seg]) -> Option<i64> {
    segments.iter().filter_map(|s| s.posted_at).min()
}

fn chunk_of(key: &str, files: &[Vec<Seg>], upload: usize) -> ReleaseChunk {
    let first = &files[0][0].file;
    let chunk_files: Vec<ChunkFile> = files
        .iter()
        .map(|f| {
            let m = &f[0].file;
            ChunkFile { name: &m.name, poster: &m.poster, subject: &m.subject, posted_at: posted_of(f), groups: &m.groups, segments: f.iter().map(|s| (s.number, s.message_id.as_str(), s.bytes)).collect() }
        })
        .collect();
    let mut segments = 0;
    let mut bytes = 0;
    let mut first_article = i64::MAX;
    let mut last_article = 0;
    let mut posted_at: Option<i64> = None;
    let mut posted_last: Option<i64> = None;
    for f in files {
        for s in f {
            if let Some(t) = s.posted_at {
                if posted_last.is_none_or(|p| t > p) {
                    posted_last = Some(t);
                }
            }
            segments += 1;
            bytes += s.bytes;
            first_article = first_article.min(s.article);
            last_article = last_article.max(s.article);
        }
        if let Some(t) = posted_of(f) {
            if posted_at.is_none_or(|p| t < p) {
                posted_at = Some(t);
            }
        }
    }
    ReleaseChunk {
        key: key.to_string(),
        upload,
        name: first.release.name.clone(),
        source: first.release.source,
        file_total: files.iter().find_map(|f| f[0].file.release.file_total_truthy()),
        poster: first.poster.clone(),
        groups: first.groups.clone(),
        posted_at,
        posted_last,
        files: files.len(),
        segments,
        bytes,
        first_article,
        last_article,
        readable: chunk_files.iter().any(|f| !is_random_file(f.name)),
        has_par2: chunk_files.iter().any(|f| names::is_par2(f.name)),
        payload: encode_chunk(&chunk_files),
        subjects: chunk_files.iter().take(SUBJECTS).map(|f| f.subject.to_string()).collect(),
    }
}

fn candidates_of(key: &str, files: &[Vec<Seg>], upload: usize) -> Vec<Candidate> {
    let mut out = Vec::new();
    let mut tail: Option<(i64, &Vec<Seg>)> = None;
    let c = |kind, s: &Seg| Candidate { release_key: key.to_string(), upload, kind, message_id: s.message_id.clone(), file: s.file.name.clone() };
    for f in files {
        let name = &f[0].file.name;
        if let Some(volume) = names::seven_zip_volume(name).filter(|&v| v > 1) {
            if tail.is_none_or(|(v, _)| volume > v) {
                tail = Some((volume, f));
            }
            continue;
        }
        if names::is_archive_start(name) {
            out.push(c("archive", &f[0]));
        } else if names::is_par2(name) && !names::is_later_volume(name) {
            out.push(c("par2", &f[0]));
        }
    }
    if let Some((_, f)) = tail {
        out.push(Candidate { release_key: key.to_string(), upload, kind: "7z-tail", message_id: f.last().unwrap().message_id.clone(), file: f[0].file.name.clone() });
    }
    if out.is_empty() && files.len() == 1 && is_random_file(&files[0][0].file.name) {
        out.push(c("lone", &files[0][0]));
    }
    out.truncate(4);
    out
}

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

    const GROUP: &str = "alt.binaries.test";

    fn line(n: i64, subject: &str, minutes: i64) -> String {
        let date = chrono::DateTime::from_timestamp_millis(1_791_194_400_000 + minutes * 60_000).unwrap().format("%a, %d %b %Y %H:%M:%S +0000");
        format!("{n}\t{subject}\tp <p@x>\t{date}\t<u{n}@test>\t\t1000\t10\tXref: news.example {GROUP}:{n}")
    }

    #[test]
    fn uploads_split_as_in_the_typescript() {
        let mut priorities = FxHashMap::default();
        priorities.insert(GROUP.to_string(), 1);
        let mut ix = RangeIndexer::new(GROUP, 1, 10_000, 1, Rules::defaults(priorities), 5);
        let mut lines: Vec<String> = (0..5).map(|i| line(100 + i, &format!(r#"Big.Release [1/2] - "Big.Release.mkv" yEnc ({}/5)"#, i + 1), i * 60)).collect();
        lines.push(line(200, r#"Big.Release [2/2] - "Big.Release.par2" yEnc (1/1)"#, 245));
        lines.extend((0..5).map(|i| line(300 + i, &format!(r#"Big.Release [1/2] - "Big.Release.mkv" yEnc ({}/5)"#, i + 1), 1440 + i)));
        ix.add_text(&lines.join("\r\n"), 10_001);
        ix.finish();
        let batch = ix.take();
        let got: Vec<(usize, usize)> = batch.releases.iter().map(|r| (r.upload, r.files)).collect();
        assert_eq!(got, vec![(0, 2), (1, 1)]);
        assert_eq!(batch.releases[0].posted_last.unwrap() - batch.releases[0].posted_at.unwrap(), 245 * 60_000);
        assert_eq!(batch.releases[0].key, batch.releases[1].key);
    }

    #[test]
    fn copies_and_fills_as_in_the_typescript() {
        let hour = 3_600_000i64;
        let meta = Rc::new(FileMeta {
            file_key: "a".into(),
            name: "a.bin".into(),
            poster: "p".into(),
            subject: "s".into(),
            total_parts: 3,
            groups: vec![],
            release: names::release_identity("p", "s", "a.bin"),
        });
        let at = |number: u32, h: f64, id: &str| Seg { file: meta.clone(), number, message_id: id.into(), bytes: 100, article: 0, posted_at: Some((h * hour as f64) as i64) };
        let mut agg = Aggregator::default();
        assert!(agg.add(vec![at(1, 10.0, "a1"), at(2, 10.0, "a2"), at(1, 10.1, "resend")]).is_empty());
        assert!(agg.add(vec![at(1, 34.0, "b1"), at(2, 34.0, "b2")]).is_empty());
        assert_eq!(agg.open.get("a").unwrap().len(), 2);
        let second = agg.add(vec![at(3, 34.2, "b3")]);
        assert_eq!(second[0].iter().map(|s| s.message_id.as_str()).collect::<Vec<_>>(), vec!["b1", "b2", "b3"]);
        let first = agg.add(vec![at(3, 58.0, "a3")]);
        assert_eq!(first[0].iter().map(|s| s.message_id.as_str()).collect::<Vec<_>>(), vec!["a1", "a2", "a3"]);
        assert!(agg.open.is_empty());
    }

#[cfg(test)]
mod unquoted_tests {
    use super::unquoted_name;

    #[test]
    fn file_names_of_subjects_without_a_quoted_one() {
        let cases = [
            ("DVDFab 8.2.0.5.rar ", Some("DVDFab 8.2.0.5.rar")),
            ("q3B9OrpKiCxUnzgtUGnp.part023.rar ", Some("q3B9OrpKiCxUnzgtUGnp.part023.rar")),
            ("New_Super_Mario_Bros._[Keygen].exe ", Some("New_Super_Mario_Bros._[Keygen].exe")),
            ("Emily_18_-_Bed.part01.rar Emily 18 bed video FULL NUDE ", Some("Emily_18_-_Bed.part01.rar")),
            ("[33/117] 674a37548b09.dat ", Some("674a37548b09.dat")),
            ("A Strange Light from the East - Eastern Influenced Western Music (1965-72) - CD2 - 07 - Rascals - Sattva.mp3 ", Some("07 - Rascals - Sattva.mp3")),
            ("pal!    [Mivina high(1).wmv\" yEnc] ", Some("Mivina high(1).wmv")),
            ("[03/21 Geroellheimer - S03E16.part01.rar\" yEnc ", Some("Geroellheimer - S03E16.part01.rar")),
            ("<Group> FP -> {EXL01~P~004} -> Alexia (3) -> VF -> [0001 of 0076] -> Exclusive-tgirls_000000-lg.jpg ", Some("Exclusive-tgirls_000000-lg.jpg")),
            ("Ballers.2014.S01E01.HDTV.x264-KILLERS[ettv] 15_07_2015.rar ", Some("Ballers.2014.S01E01.HDTV.x264-KILLERS[ettv] 15_07_2015.rar")),
            ("Computer Bild - Ausgabe 152015 - 15_07_2015.rar ", Some("Computer Bild - Ausgabe 152015 - 15_07_2015.rar")),
            ("<abm> <Duke> here's a little thanksgiving present: AB: part2 0573-1002 043.jpg ", Some("043.jpg")),
            ("xlady post You, Me And Dupree www.x2l.nl [001/106] 'You, Me And Dupree.nfo'", Some("You, Me And Dupree.nfo")),
            ("[01/77][LIBRATEAM_M2219009.par2] Onbeperkt downloaden met een snelheid van 1,22 MB p.s. en dat voor maar 7,95 p.m. www.libranews.nl", Some("LIBRATEAM_M2219009.par2")),
            ("patensas post -^-[Mnozil Brass - Seven.nzb]-^-www.usenet2day.cc -^-[000/107]-^-www.libranews.nl-^- yEnc", Some("Mnozil Brass - Seven.nzb")),
            ("[7w] - 9BbEV2MrTi59GBTEFlVrssBrXNwXf2SK9cQEeDjg yEnc ", None),
            ("Re: Will somebody answer the question? ", None),
        ];
        for (text, want) in cases {
            assert_eq!(unquoted_name(text).as_deref(), want, "{text}");
        }
    }
}

#[cfg(test)]
mod beside_quotes_tests {
    use super::name_beside_quotes;

    #[test]
    fn a_name_beside_a_quoted_word() {
        assert_eq!(name_beside_quotes("Official", "My \"Official\" remaining set's of Inna, Please help up to #69 if you can 025.jpg [25/74] - yEnc ").as_deref(), Some("025.jpg"));
        assert_eq!(name_beside_quotes("Dr. Lust", "\"Dr. Lust\" - Lily Marlene, Vanessa Del Rio, Scorpio? - yEnc - [12/21] - Ed_DRL_VDR_LM.part09.rar ").as_deref(), Some("Ed_DRL_VDR_LM.part09.rar"));
        assert_eq!(name_beside_quotes("1f0554e5fec14b8b05ca", "77cd6d03d19281a775f5bdc5 [2/8] - \"1f0554e5fec14b8b05ca\" yEnc ").as_deref(), None);
        assert_eq!(name_beside_quotes("x.rar", "\"x.rar\" other.zip ").as_deref(), None);
    }
}
}