/**
 * StdinBuffer buffers input and emits complete sequences.
 *
 * This is necessary because stdin data events can arrive in partial chunks,
 * especially for escape sequences like mouse events. Without buffering,
 * partial sequences can be misinterpreted as regular keypresses.
 *
 * For example, the mouse SGR sequence `\x1b[<35;20;5m` might arrive as:
 * - Event 1: `\x1b`
 * - Event 2: `[<35`
 * - Event 3: `;20;5m`
 *
 * The buffer accumulates these until a complete sequence is detected.
 * Call the `process()` method to feed input data.
 *
 * Based on code from OpenTUI (https://github.com/anomalyco/opentui)
 * MIT License - Copyright (c) 2025 opentui
 */
import { EventEmitter } from "events";
const ESC = "\x1b";
const BRACKETED_PASTE_START = "\x1b[200~";
const BRACKETED_PASTE_END = "\x1b[201~";
/**
 * Check if a string is a complete escape sequence or needs more data
 */
function isCompleteSequence(data) {
    if (!data.startsWith(ESC)) {
        return "not-escape";
    }
    if (data.length === 1) {
        return "incomplete";
    }
    const afterEsc = data.slice(1);
    // CSI sequences: ESC [
    if (afterEsc.startsWith("[")) {
        // Check for old-style mouse sequence: ESC[M + 3 bytes
        if (afterEsc.startsWith("[M")) {
            // Old-style mouse needs ESC[M + 3 bytes = 6 total
            return data.length >= 6 ? "complete" : "incomplete";
        }
        return isCompleteCsiSequence(data);
    }
    // OSC sequences: ESC ]
    if (afterEsc.startsWith("]")) {
        return isCompleteOscSequence(data);
    }
    // DCS sequences: ESC P ... ESC \ (includes XTVersion responses)
    if (afterEsc.startsWith("P")) {
        return isCompleteDcsSequence(data);
    }
    // APC sequences: ESC _ ... ESC \ (includes Kitty graphics responses)
    if (afterEsc.startsWith("_")) {
        return isCompleteApcSequence(data);
    }
    // SS3 sequences: ESC O
    if (afterEsc.startsWith("O")) {
        // ESC O followed by a single character
        return afterEsc.length >= 2 ? "complete" : "incomplete";
    }
    // Meta key sequences: ESC followed by a single character
    if (afterEsc.length === 1) {
        return "complete";
    }
    // Unknown escape sequence - treat as complete
    return "complete";
}
/**
 * Check if CSI sequence is complete
 * CSI sequences: ESC [ ... followed by a final byte (0x40-0x7E)
 */
function isCompleteCsiSequence(data) {
    if (!data.startsWith(`${ESC}[`)) {
        return "complete";
    }
    // Need at least ESC [ and one more character
    if (data.length < 3) {
        return "incomplete";
    }
    const payload = data.slice(2);
    // CSI sequences end with a byte in the range 0x40-0x7E (@-~)
    // This includes all letters and several special characters
    const lastChar = payload[payload.length - 1];
    const lastCharCode = lastChar.charCodeAt(0);
    if (lastCharCode >= 0x40 && lastCharCode <= 0x7e) {
        // Special handling for SGR mouse sequences
        // Format: ESC[<B;X;Ym or ESC[<B;X;YM
        if (payload.startsWith("<")) {
            // Must have format: <digits;digits;digits[Mm]
            const mouseMatch = /^<\d+;\d+;\d+[Mm]$/.test(payload);
            if (mouseMatch) {
                return "complete";
            }
            // If it ends with M or m but doesn't match the pattern, still incomplete
            if (lastChar === "M" || lastChar === "m") {
                // Check if we have the right structure
                const parts = payload.slice(1, -1).split(";");
                if (parts.length === 3 && parts.every((p) => /^\d+$/.test(p))) {
                    return "complete";
                }
            }
            return "incomplete";
        }
        return "complete";
    }
    return "incomplete";
}
/**
 * Check if OSC sequence is complete
 * OSC sequences: ESC ] ... ST (where ST is ESC \ or BEL)
 */
function isCompleteOscSequence(data) {
    if (!data.startsWith(`${ESC}]`)) {
        return "complete";
    }
    // OSC sequences end with ST (ESC \) or BEL (\x07)
    if (data.endsWith(`${ESC}\\`) || data.endsWith("\x07")) {
        return "complete";
    }
    return "incomplete";
}
/**
 * Check if DCS (Device Control String) sequence is complete
 * DCS sequences: ESC P ... ST (where ST is ESC \)
 * Used for XTVersion responses like ESC P >| ... ESC \
 */
function isCompleteDcsSequence(data) {
    if (!data.startsWith(`${ESC}P`)) {
        return "complete";
    }
    // DCS sequences end with ST (ESC \)
    if (data.endsWith(`${ESC}\\`)) {
        return "complete";
    }
    return "incomplete";
}
/**
 * Check if APC (Application Program Command) sequence is complete
 * APC sequences: ESC _ ... ST (where ST is ESC \)
 * Used for Kitty graphics responses like ESC _ G ... ESC \
 */
function isCompleteApcSequence(data) {
    if (!data.startsWith(`${ESC}_`)) {
        return "complete";
    }
    // APC sequences end with ST (ESC \)
    if (data.endsWith(`${ESC}\\`)) {
        return "complete";
    }
    return "incomplete";
}
/**
 * Split accumulated buffer into complete sequences
 */
function parseUnmodifiedKittyPrintableCodepoint(sequence) {
    const match = sequence.match(/^\x1b\[(\d+)(?::\d*)?(?::\d+)?u$/);
    if (!match)
        return undefined;
    const codepoint = parseInt(match[1], 10);
    return codepoint >= 32 ? codepoint : undefined;
}
function extractCompleteSequences(buffer) {
    const sequences = [];
    let pos = 0;
    while (pos < buffer.length) {
        const remaining = buffer.slice(pos);
        // Try to extract a sequence starting at this position
        if (remaining.startsWith(ESC)) {
            // Find the end of this escape sequence
            let seqEnd = 1;
            while (seqEnd <= remaining.length) {
                const candidate = remaining.slice(0, seqEnd);
                const status = isCompleteSequence(candidate);
                if (status === "complete") {
                    sequences.push(candidate);
                    pos += seqEnd;
                    break;
                }
                else if (status === "incomplete") {
                    seqEnd++;
                }
                else {
                    // Should not happen when starting with ESC
                    sequences.push(candidate);
                    pos += seqEnd;
                    break;
                }
            }
            if (seqEnd > remaining.length) {
                return { sequences, remainder: remaining };
            }
        }
        else {
            // Not an escape sequence - take a single character
            sequences.push(remaining[0]);
            pos++;
        }
    }
    return { sequences, remainder: "" };
}
/**
 * Buffers stdin input and emits complete sequences via the 'data' event.
 * Handles partial escape sequences that arrive across multiple chunks.
 */
export class StdinBuffer extends EventEmitter {
    buffer = "";
    timeout = null;
    timeoutMs;
    pasteMode = false;
    pasteBuffer = "";
    pendingKittyPrintableCodepoint;
    constructor(options = {}) {
        super();
        this.timeoutMs = options.timeout ?? 10;
    }
    process(data) {
        // Clear any pending timeout
        if (this.timeout) {
            clearTimeout(this.timeout);
            this.timeout = null;
        }
        // Handle high-byte conversion (for compatibility with parseKeypress)
        // If buffer has single byte > 127, convert to ESC + (byte - 128)
        let str;
        if (Buffer.isBuffer(data)) {
            if (data.length === 1 && data[0] > 127) {
                const byte = data[0] - 128;
                str = `\x1b${String.fromCharCode(byte)}`;
            }
            else {
                str = data.toString();
            }
        }
        else {
            str = data;
        }
        if (str.length === 0 && this.buffer.length === 0) {
            this.emitDataSequence("");
            return;
        }
        this.buffer += str;
        if (this.pasteMode) {
            this.pasteBuffer += this.buffer;
            this.buffer = "";
            const endIndex = this.pasteBuffer.indexOf(BRACKETED_PASTE_END);
            if (endIndex !== -1) {
                const pastedContent = this.pasteBuffer.slice(0, endIndex);
                const remaining = this.pasteBuffer.slice(endIndex + BRACKETED_PASTE_END.length);
                this.pasteMode = false;
                this.pasteBuffer = "";
                this.pendingKittyPrintableCodepoint = undefined;
                this.emit("paste", pastedContent);
                if (remaining.length > 0) {
                    this.process(remaining);
                }
            }
            return;
        }
        const startIndex = this.buffer.indexOf(BRACKETED_PASTE_START);
        if (startIndex !== -1) {
            if (startIndex > 0) {
                const beforePaste = this.buffer.slice(0, startIndex);
                const result = extractCompleteSequences(beforePaste);
                for (const sequence of result.sequences) {
                    this.emitDataSequence(sequence);
                }
            }
            this.pendingKittyPrintableCodepoint = undefined;
            this.buffer = this.buffer.slice(startIndex + BRACKETED_PASTE_START.length);
            this.pasteMode = true;
            this.pasteBuffer = this.buffer;
            this.buffer = "";
            const endIndex = this.pasteBuffer.indexOf(BRACKETED_PASTE_END);
            if (endIndex !== -1) {
                const pastedContent = this.pasteBuffer.slice(0, endIndex);
                const remaining = this.pasteBuffer.slice(endIndex + BRACKETED_PASTE_END.length);
                this.pasteMode = false;
                this.pasteBuffer = "";
                this.pendingKittyPrintableCodepoint = undefined;
                this.emit("paste", pastedContent);
                if (remaining.length > 0) {
                    this.process(remaining);
                }
            }
            return;
        }
        const result = extractCompleteSequences(this.buffer);
        this.buffer = result.remainder;
        for (const sequence of result.sequences) {
            this.emitDataSequence(sequence);
        }
        if (this.buffer.length > 0) {
            this.timeout = setTimeout(() => {
                const flushed = this.flush();
                for (const sequence of flushed) {
                    this.emitDataSequence(sequence);
                }
            }, this.timeoutMs);
        }
    }
    emitDataSequence(sequence) {
        const rawCodepoint = sequence.length === 1 ? sequence.codePointAt(0) : undefined;
        if (rawCodepoint !== undefined && rawCodepoint === this.pendingKittyPrintableCodepoint) {
            this.pendingKittyPrintableCodepoint = undefined;
            return;
        }
        this.pendingKittyPrintableCodepoint = parseUnmodifiedKittyPrintableCodepoint(sequence);
        this.emit("data", sequence);
    }
    flush() {
        if (this.timeout) {
            clearTimeout(this.timeout);
            this.timeout = null;
        }
        if (this.buffer.length === 0) {
            return [];
        }
        const sequences = [this.buffer];
        this.buffer = "";
        this.pendingKittyPrintableCodepoint = undefined;
        return sequences;
    }
    clear() {
        if (this.timeout) {
            clearTimeout(this.timeout);
            this.timeout = null;
        }
        this.buffer = "";
        this.pasteMode = false;
        this.pasteBuffer = "";
        this.pendingKittyPrintableCodepoint = undefined;
    }
    getBuffer() {
        return this.buffer;
    }
    destroy() {
        this.clear();
    }
}
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