import { Readable } from 'stream';
import { Config, Mode } from './interfaces';
/**
 * The pager session state, like less's globals spread across its C
 * files: one live session at a time, reset by resetSession() when a
 * pager entry starts. Module scope (rather than contentPager's
 * closure) keeps every field initialized before any key can arrive
 * and lets feature modules share the state without threading it.
 */
export declare const session: {
    /** The displayed lines; the help screen swaps them out. */
    content: string[];
    /** The raw input lines; pipes and streamed files append here. */
    fullContent: string[];
    /** The main content parked while the help screen displays. */
    prevContent: string[];
    /** The main config parked while the help screen displays. */
    prevConfig: Config;
    /** The main mode flags parked while the help screen displays. */
    prevMode: Record<Mode, boolean>;
    /** The SOURCE lines of the help page on screen: an O_REPAINT option
     *  toggled inside it re-transforms the page being looked at, and
     *  there is more than one (the commands help, --lesskey-help). */
    helpSource: string[];
    /** The key sequence being dispatched. */
    key: string;
    /** Pending ESC count while a sequence collects. */
    escCount: number;
    /** The digit-prefix buffer, like less's cmdbuf number. */
    buffer: string[];
    /** Queued + commands for the first prompt (less's ungotten input). */
    pendingFirstCmds: string[];
    /** The errmsgs gate's ungot key, ordinary input after the +cmds. */
    ungotStartKey: string;
    /** Waiting after !/| with the terminal handed to the shell. */
    shellPause: false | "shell" | "pager";
    /** True once the session ended; exit() resolves the main loop. */
    exited: boolean;
    exit: () => void;
    /** True when the help screen IS the input (--help/-?), like less's
     *  dohelp FAKE_HELPFILE: q then quits instead of restoring. */
    startupHelp: boolean;
    /** Inside bracketed paste markers, text accepted (--no-paste). */
    pasting: boolean;
    /** Dropping pasted input until the end marker or the timeout. */
    ignoringPaste: boolean;
    ignoreStart: number;
    /** The F command's polling timer. */
    followTimer: ReturnType<typeof setInterval> | null;
    /** A LESSOPEN edit warning waiting for RETURN before v runs. */
    pendingEditWarn: boolean;
    /** Collected keys of a partially matched lesskey user binding. */
    userSeq: string;
    /** The last --emouse click row, and hdrag/vdrag origins, like
     *  less's last_drag_x/y. */
    lastClickY: number;
    lastDragX: number;
    lastDragY: number;
    /** The active & display filter over fullContent. */
    lastFilter: ((line: string) => boolean) | null;
    /** True when a & filter is hiding lines BELOW the bottom line.
     *  less's eof_displayed asks where the bottom line ends in the FILE
     *  (forwback.c:76), which is not the same question as mode.EOF -
     *  "is anything left to display". They differ only here. */
    filterHidesTail: boolean;
    /** less's soft_eof, as a flag: a forward read has RETURNED EOF since
     *  the filter was set (forwback.c:310), or a jump to the end walked
     *  back through it (jump.c:62). Either makes the bottom line count
     *  as the end even with a filtered tail behind it. Cleared when a
     *  new filter is set, like command.c:282. */
    softEofSeen: boolean;
    /** The process title to restore at exit. */
    processTitle: string;
    pipeStream: Readable | null;
    pipePaused: boolean;
    pipeDrainTo: (() => void) | null;
    detachPipe: () => void;
    /** Bytes of pipe data kept before the oldest recycle away: -B
     *  limits it to the -b buffer space up front (ch.c's maxbufs for
     *  pipes); otherwise the budget locks in at the first sign of
     *  heap pressure, less's failed-allocation moment. */
    pipeBudget: number;
    /** less paints arriving lines only while the initial forw() fills
     *  the first screenful; afterwards an idle pager never repaints
     *  on new pipe data (F is the follow command). */
    pipeFirstFill: boolean;
    /** Keys typed during the initial fill wait like less's check_poll
     *  queuing tty chars (ungetcc_back) until the read completes. */
    fillKeys: string[];
    /** The "Waiting for data..." state, less's waiting_for_data. */
    pipeWaiting: boolean;
    /** less's pending S_INTERRUPT: the next gate's ungot key clears. */
    intrPending: boolean;
    /** Feeds deferred keys back through the session's key handler. */
    feedKeys: (data: string) => void;
    /** -F reads the pipe before any terminal init, like less's
     *  get_one_screen: nothing reaches the screen while it decides. */
    pipeProbing: boolean;
};
/**
 * Starts a fresh session over the given content, like a new less
 * process resetting its globals.
 */
export declare function resetSession(content: string[]): void;
/**
 * Derives the display lines from the raw input: the & filter
 * applies first, then the -s/-x/-r transform pipeline.
 */
export declare function deriveContent(): string[];
/**
 * $LESS_SHELL_LINES reserves shell rows in one-screen tests, like
 * less get_one_screen's `nlines + shell_lines <= sc_height`.
 */
export declare function shellReserveLines(): number;