import { spawn } from "node:child_process";
import type { NativePtyLoadResult } from "./native-loader.ts";
export interface PipeFallbackSessionOptions {
    readonly command: string;
    readonly args?: readonly string[];
    readonly cwd?: string;
    readonly env?: Readonly<Record<string, string | undefined>>;
    readonly timeoutMs?: number;
}
export interface PipeFallbackSessionError {
    readonly code: "spawn_error";
    readonly message: string;
}
export interface PipeFallbackSessionExit {
    readonly exitCode: number | null;
    readonly signal: NodeJS.Signals | null;
    readonly timedOut: boolean;
    readonly error?: PipeFallbackSessionError;
}
export type PipeFallbackOperationResult = {
    readonly ok: true;
    readonly note: string;
} | {
    readonly ok: false;
    readonly code: "exited" | "not_pty" | "not_started" | "stdin_unavailable";
    readonly note: string;
};
type ChildProcessHandle = ReturnType<typeof spawn>;
type DataHandler = (chunk: Buffer) => void;
type ExitHandler = (exit: PipeFallbackSessionExit) => void;
export declare function isPipeFallbackForced(env?: Readonly<Record<string, string | undefined>>): boolean;
export declare function shouldUsePipeFallback(nativeLoadResult: NativePtyLoadResult, env?: Readonly<Record<string, string | undefined>>): boolean;
/**
 * Terminate the child, preferring its whole process group on POSIX. The
 * detached child is its own group leader and grandchildren inherit the stdio
 * pipes, so leaving them alive keeps 'close' from ever firing (the POSIX twin
 * of the Windows taskkill /T branch below). Every path that stops a child must
 * go through here: when the group signal is unavailable (Windows, no pid) or
 * the group is already gone, it still falls back to a direct kill, so the
 * child is never left running.
 */
export declare function terminateChildTree(child: Pick<ChildProcessHandle, "pid" | "kill">, signal: NodeJS.Signals): "group" | "direct";
export declare class PipeFallbackSession {
    readonly backend = "pipe-fallback";
    readonly note = "Running with child_process pipe fallback because no PTY backend is active; terminal screen state and resize are unavailable.";
    readonly options: PipeFallbackSessionOptions;
    private child;
    private exitResult;
    private exitPromise;
    private resolveExit;
    private spawnError;
    private timedOut;
    private timeoutHandle;
    private readonly dataHandlers;
    private readonly exitHandlers;
    constructor(options: PipeFallbackSessionOptions);
    start(): this;
    onData(handler: DataHandler): () => void;
    onExit(handler: ExitHandler): () => void;
    write(data: string | Uint8Array): PipeFallbackOperationResult;
    closeInput(): PipeFallbackOperationResult;
    resize(cols: number, rows: number): PipeFallbackOperationResult;
    kill(signal?: NodeJS.Signals): PipeFallbackOperationResult;
    waitExit(): Promise<PipeFallbackSessionExit>;
    private emitData;
    private settleExit;
}
export declare function createPipeFallbackSession(options: PipeFallbackSessionOptions): PipeFallbackSession;
export {};
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