[tab] crowd-pilot-extension/src/extension.ts (typescript)
import * as vscode from 'vscode';
import * as http from 'http';
import * as fs from 'fs';
import * as path from 'path';
import { Buffer } from 'buffer';

// -------------------- Preference Data Collection --------------------

interface PreferenceSample {
	timestamp: number;
	context: Array<{ role: string; content: string }>;
	completion: {
		rawModelOutput: string;
		parsedAction: Action | null;
		avgLogprob: number;
	};
	outcome: 'accepted' | 'rejected' | 'ignored' | null;
	outcomeTimestamp: number | null;
	modelName: string;
}

interface PendingPreferenceSample {
	sample: PreferenceSample;
	shownAt: number;
}

let pendingPreferenceSample: PendingPreferenceSample | null = null;

function getPreferenceLogPath(): string {
	const cfg = getConfig();
	if (cfg.preferenceLogPath) {
		return cfg.preferenceLogPath;
	}
	const workspaceFolders = vscode.workspace.workspaceFolders;
	if (workspaceFolders) {
		return path.join(workspaceFolders[0].uri.fsPath, '.crowd-pilot-preferences.jsonl');
	}
	throw new Error("No preference log path found.")
}

/**
 * Log a preference sample to the JSONL file.
 * Each line is a complete JSON object for easy streaming/parsing.
 */
function logPreferenceSample(sample: PreferenceSample): void {
	const cfg = getConfig();
	if (!cfg.enablePreferenceLogging) {
		console.log(`[crowd-pilot] Preference logging disabled, skipping sample`);
		return;
	}

	const logPath = getPreferenceLogPath();
	const line = JSON.stringify(sample) + '
';
	
	fs.appendFile(logPath, line, (err) => {
		if (err) {
			console.error('[crowd-pilot] Failed to log preference sample:', err);
		} else {
			console.log(`[crowd-pilot] Logged preference sample, outcome: (${sample.outcome})`);
		}
	});
}

/**
 * Create a new pending preference sample when showing a preview.
 * This captures all context needed for reward model training.
 */
function createPendingPreferenceSample(
	conversationMessages: Array<{ role: string; content: string }>,
	rawModelOutput: string,
	parsedAction: Action | null,
	avgLogprob: number,
	modelName: string
): void {
	const sample: PreferenceSample = {
		timestamp: Date.now(),
		context: conversationMessages,
		completion: {
			rawModelOutput,
			parsedAction,
			avgLogprob,
		},
		outcome: null,
		outcomeTimestamp: null,
		modelName,
	};

	pendingPreferenceSample = {
		sample,
		shownAt: Date.now(),
	};
}

/**
 * Record the outcome of the current pending sample and log it.
 */
function recordPreferenceOutcome(outcome: 'accepted' | 'rejected' | 'ignored'): void {
	if (!pendingPreferenceSample) {
		return;
	}

	const sample = pendingPreferenceSample.sample;
	sample.outcome = outcome;
	sample.outcomeTimestamp = Date.now();

	logPreferenceSample(sample);

	pendingPreferenceSample = null;
}

/**
 * Mark any pending sample as ignored (user moved on without explicit accept/reject).
 */
function markPendingAsIgnored(): void {
	if (pendingPreferenceSample) {
		recordPreferenceOutcome('ignored');
	}
}

type Action =
| { kind: 'showTextDocument' }
| { kind: 'setSelections', selections: Array<{ start: [number, number], end: [number, number] }> }
| { kind: 'editInsert', position: [number, number], text: string }
| { kind: 'editDelete', range: { start: [number, number], end: [number, number] } }
| { kind: 'editReplace', range: { start: [number, number], end: [number, number] }, text: string }
| { kind: 'terminalShow' }
| { kind: 'terminalSendText', text: string }
| { kind: 'openFile', filePath: string, selections?: Array<{ start: [number, number], end: [number, number] }> };

// Configuration helper
function getConfig() {
	const config = vscode.workspace.getConfiguration('crowd-pilot');
	return {
		hostname: config.get<string>('hostname', 'hai001'),
		port: config.get<number>('port', 30000),
		basePath: config.get<string>('basePath', '/v1/chat/completions'),
		modelName: config.get<string>('modelName', 'qwen/qwen3-8b'),
		minAvgLogprob: config.get<number>('minAvgLogprob', -1.0),
		maxContextTokens: config.get<number>('maxContextTokens', 120000),
		preferenceLogPath: config.get<string>('preferenceLogPath', ''),
		enablePreferenceLogging: config.get<boolean>('enablePreferenceLogging', true),
	};
}

// -------------------- Context Window Management --------------------

/**
 * Estimate token count from text using character-based heuristic.
 * Uses ~4 characters per token as a rough approximation for most LLMs.
 */
function estimateTokens(text: string): number {
	return Math.ceil(text.length / 4);
}

/**
 * Truncate conversation messages to fit within the context window.
 * Assumes system prompt is the first message. Drops oldest conversation messages first.
 */
function truncateToContextLimit(
	messages: Array<{ role: 'system' | 'user' | 'assistant'; content: string }>,
	maxTokens: number
): Array<{ role: 'system' | 'user' | 'assistant'; content: string }> {
	if (messages.length === 0) { return messages; }

	const systemTokens = estimateTokens(messages[0].content);
	const availableTokens = maxTokens - systemTokens;

	const tokenCounts = messages.slice(1).map(m => estimateTokens(m.content));
	const totalConversationTokens = tokenCounts.reduce((a, b) => a + b, 0);

	if (totalConversationTokens <= availableTokens) {
		return messages;
	}

	let keptTokens = 0;
	let cutoffIndex = tokenCounts.length;
	for (let i = tokenCounts.length - 1; i >= 0; i--) {
		if (keptTokens + tokenCounts[i] <= availableTokens) {
			keptTokens += tokenCounts[i];
			cutoffIndex = i;
		} else {
			break;
		}
	}

	console.log(`[crowd-pilot] Truncated ${cutoffIndex} oldest messages (${systemTokens + totalConversationTokens} -> ${systemTokens + keptTokens} tokens)`);
	return [messages[0], ...messages.slice(cutoffIndex + 1)];
}

// -------------------- Serialization Helpers (mirrors serialization_utils.py) --------------------
const ANSI_CSI_RE = /\x1b\[[0-9;?]*[ -/]*[@-~]/g;
const ANSI_OSC_TERMINATED_RE = /\x1b\][\s\S]*?(?:\x07|\x1b\\)/g;
const ANSI_OSC_LINE_FALLBACK_RE = /\x1b\][^
]*$/g;

// NOTE (f.srambical): Make sure that these are the parameters that were used during serialization
const VIEWPORT_RADIUS = 10;
const COALESCE_RADIUS = 5;
// FIXME (f.srambical): this slightly differs from the logic in @file:crowd-pilot/crowd_pilot/serialization_utils.py
// as we only approximate the token count
const MAX_TOKENS_PER_MESSAGE = 2048;
const MAX_TOKENS_PER_TERMINAL_OUTPUT = 256;

function cleanText(text: string): string {
	return text.replace(/
/g, '
').replace(/
/g, '
').trimEnd();
}

function fencedBlock(language: string | null, content: string): string {
	const lang = (language || '').toLowerCase();
	return `\`\`\`${lang}
${content}
\`\`\`
`;
}

function applyChange(content: string, offset: number, length: number, newText: string): string {
	let base = String(content);
	const text = (newText ?? '').replace(/\
/g, '
').replace(/\
/g, '
');
	if (offset > base.length) {
		base = base + ' '.repeat(offset - base.length);
	}
	return base.slice(0, offset) + text + base.slice(offset + length);
}

function applyBackspaces(text: string): string {
	const out: string[] = [];
	for (const ch of text) {
		if (ch === '\b') {
			if (out.length > 0) {
				out.pop();
			}
		} else {
			out.push(ch);
		}
	}
	return out.join('');
}

function normalizeTerminalOutput(raw: string): string {
	if (!raw) { return raw; }
	let s = applyBackspaces(raw);
	s = s.replace(ANSI_OSC_TERMINATED_RE, '');
	s = s.split('
').map(line => line.replace(ANSI_OSC_LINE_FALLBACK_RE, '')).join('
');
	const resolvedLines: string[] = [];
	for (const seg of s.split('
')) {
		const parts = seg.split('
');
		let chosen = '';
		for (let i = parts.length - 1; i >= 0; i--) {
			if (parts[i] !== '') {
				chosen = parts[i];
				break;
			}
		}
		if (chosen === '' && parts.length > 0) {
			chosen = parts[parts.length - 1];
		}
		resolvedLines.push(chosen);
	}
	s = resolvedLines.join('
');
	s = s.replace(ANSI_CSI_RE, '');
	s = s.replace(/\x07/g, '');
	return s;
}

function lineNumberedOutput(content: string, startLine?: number, endLine?: number): string {
	const lines = content.split(/
?
/);
	const total = (lines.length === 1 && lines[0] === '') ? 0 : lines.length;
	if (total === 0) { return ''; }
	const s = startLine !== undefined ? Math.max(1, Math.min(startLine, total)) : 1;
	const e = endLine !== undefined ? Math.max(1, Math.min(endLine, total)) : total;
	const buf: string[] = [];
	for (let idx = s; idx <= e; idx++) {
		const lineText = lines[idx - 1] ?? '';
		buf.push(`${idx.toString().padStart(6, ' ')}	${lineText}`);
	}
	return buf.join('
');
}

function serializeComputeViewport(totalLines: number, centerLine: number, radius: number): { start: number; end: number } {
	if (totalLines <= 0) { return { start: 1, end: 0 }; }
	const start = Math.max(1, centerLine - radius);
	const end = Math.min(totalLines, centerLine + radius);
	return { start, end };
}

function escapeSingleQuotesForSed(text: string): string {
	return text.replace(/'/g, "'\"'\"'");
}

type OpcodeTag = "replace" | "delete" | "insert" | "equal";

type Opcode = [OpcodeTag, number, number, number, number];

class SequenceMatcher {
	private a: string[];
	private b: string[];
	private b2j: Map<string, number[]> | null = null;
	private matchingBlocks: Array<{ i: number; j: number; n: number }> | null = null;
	private opcodesCache: Opcode[] | null = null;

	constructor(a: string[], b: string[]) {
		this.a = a;
		this.b = b;
		this.chainB();
	}

	// Exact port of difflib's __chain_b assuming junk=None and autojunk=False
	private chainB() {
		this.b2j = new Map();
		for (let i = 0; i < this.b.length; i++) {
			const elt = this.b[i];
			let indices = this.b2j.get(elt);
			if (!indices) {
				indices = [];
				this.b2j.set(elt, indices);
			}
			indices.push(i);
		}
	}

	// Exact port of difflib's find_longest_match assuming junk=None
	private findLongestMatch(alo: number, ahi: number, blo: number, bhi: number) {
		const b2j = this.b2j!;

		let besti = alo;
		let bestj = blo;
		let bestsize = 0;

		let j2len = new Map<number, number>();

		for (let i = alo; i < ahi; i++) {
			const newj2len = new Map<number, number>();
			const elt = this.a[i];
			const indices = b2j.get(elt);
			if (indices) {
				for (const j of indices) {
					if (j < blo) { continue; }
					if (j >= bhi) { break; }
					const k = (j2len.get(j - 1) ?? 0) + 1;
					newj2len.set(j, k);
					if (k > bestsize) {
						besti = i - k + 1;
						bestj = j - k + 1;
						bestsize = k;
					}
				}
			}
			j2len = newj2len;
		}

		// bjunk is always empty since we assume junk=None
		while (besti > alo && bestj > blo && this.a[besti - 1] === this.b[bestj - 1]) {
			besti--;
			bestj--;
			bestsize++;
		}
		while (
			besti + bestsize < ahi &&
			bestj + bestsize < bhi &&
			this.a[besti + bestsize] === this.b[bestj + bestsize]
		) {
			bestsize++;
		}

		return { i: besti, j: bestj, n: bestsize };
	}

	// Exact port of difflib's get_matching_blocks
	private getMatchingBlocks() {
		if (this.matchingBlocks !== null) { return this.matchingBlocks; }

		const la = this.a.length;
		const lb = this.b.length;

		const queue: Array<[number, number, number, number]> = [[0, la, 0, lb]];
		const matchingBlocks: Array<{ i: number; j: number; n: number }> = [];

		while (queue.length) {
			const [alo, ahi, blo, bhi] = queue.pop()!;
			const match = this.findLongestMatch(alo, ahi, blo, bhi);
			const { i, j, n } = match;
			if (n > 0) {
				matchingBlocks.push(match);
				if (alo < i && blo < j) {
					queue.push([alo, i, blo, j]);
				}
				if (i + n < ahi && j + n < bhi) {
					queue.push([i + n, ahi, j + n, bhi]);
				}
			}
		}

		// Sort lexicographically by (i, j, n) to match Python's tuple sort behavior
		matchingBlocks.sort((a, b) => {
			if (a.i !== b.i) { return a.i - b.i; }
			if (a.j !== b.j) { return a.j - b.j; }
			return a.n - b.n;
		});

		let i1 = 0;
		let j1 = 0;
		let k1 = 0;
		const result: Array<{ i: number; j: number; n: number }> = [];

		for (const m of matchingBlocks) {
			if (i1 + k1 === m.i && j1 + k1 === m.j) {
				k1 += m.n;
			} else {
				if (k1 > 0) {
					result.push({ i: i1, j: j1, n: k1 });
				}
				i1 = m.i;
				j1 = m.j;
				k1 = m.n;
			}
		}
		if (k1 > 0) {
			result.push({ i: i1, j: j1, n: k1 });
		}

		result.push({ i: la, j: lb, n: 0 });

		this.matchingBlocks = result;
		return result;
	}

	// Exact port of difflib's get_opcodes
	getOpcodes(): Opcode[] {
		if (this.opcodesCache) { return this.opcodesCache; }

		const opcodes: Opcode[] = [];
		let i = 0;
		let j = 0;

		for (const m of this.getMatchingBlocks()) {
			const tag: OpcodeTag = "equal";
			const ai = m.i;
			const bj = m.j;
			const n = m.n;

			let tagToUse: OpcodeTag | null = null;

			if (i < ai && j < bj) {
				tagToUse = "replace";
			} else if (i < ai) {
				tagToUse = "delete";
			} else if (j < bj) {
				tagToUse = "insert";
			}

			if (tagToUse) {
				opcodes.push([tagToUse, i, ai, j, bj]);
			}
			if (n > 0) {
				opcodes.push([tag, ai, ai + n, bj, bj + n]);
			}
			i = ai + n;
			j = bj + n;
		}

		this.opcodesCache = opcodes;
		return opcodes;
	}
}


export function computeChangedBlockLines(before: string, after: string): {
	startBefore: number;
	endBefore: number;
	startAfter: number;
	endAfter: number;
	replacementLines: string[];
} {
	const beforeLines = before.split(/
?
/);
	const afterLines = after.split(/
?
/);

	const sm = new SequenceMatcher(beforeLines, afterLines);
	const allOpcodes = sm.getOpcodes();
	const nonEqual = allOpcodes.filter(op => op[0] !== "equal");

	if (nonEqual.length === 0) {
		throw new Error(
			"Opcode list cannot be empty! Likely a bug in the diff computation."
		);
	}

	const first = nonEqual[0];
	const last = nonEqual[nonEqual.length - 1];

	// i1/i2 refer to 'before' indices, j1/j2 to 'after'
	const startBefore = Math.max(1, first[1] + 1);
	const endBefore = last[2];
	const startAfter = Math.max(1, first[3] + 1);
	const endAfter = last[4];
	const replacementLines = afterLines.slice(first[3], last[4]);

	return { startBefore, endBefore, startAfter, endAfter, replacementLines };
}
// -------------------- Conversation State Manager --------------------
interface ConversationMessage {
	from: 'User' | 'Assistant';
	value: string;
}

class ConversationStateManager {
	private messages: ConversationMessage[] = [];
	private fileStates: Map<string, string> = new Map();
	private perFileViewport: Map<string, { start: number; end: number } | null> = new Map();
	private filesOpenedInConversation: Set<string> = new Set();
	private terminalOutputBuffer: string[] = [];
	private pendingEditsBefore: Map<string, string | null> = new Map();
	private pendingEditRegions: Map<string, { start: number; end: number } | null> = new Map();

	constructor() {}

	reset(): void {
		this.messages = [];
		this.fileStates.clear();
		this.perFileViewport.clear();
		this.filesOpenedInConversation.clear();
		this.terminalOutputBuffer = [];
		this.pendingEditsBefore.clear();
		this.pendingEditRegions.clear();
	}

	getMessages(): ConversationMessage[] {
		return [...this.messages];
	}

	getFileContent(filePath: string): string {
		return this.fileStates.get(filePath) ?? '';
	}

	private appendMessage(message: ConversationMessage): void {
		const tokens = estimateTokens(message.value);
		if (tokens > MAX_TOKENS_PER_MESSAGE) {
			const maxChars = MAX_TOKENS_PER_MESSAGE * 4;
			message.value = message.value.slice(0, maxChars);
		}
		this.messages.push(message);
	}

	private maybeCaptureFileContents(filePath: string, content: string): void {
		if (this.filesOpenedInConversation.has(filePath)) {
			return;
		}
		const cmd = `cat -n ${filePath}`;
		this.appendMessage({
			from: 'Assistant',
			value: fencedBlock('bash', cleanText(cmd)),
		});
		const output = lineNumberedOutput(content);
		this.appendMessage({
			from: 'User',
			value: `<stdout>
${output}
</stdout>`,
		});
		this.filesOpenedInConversation.add(filePath);
	}

	flushTerminalOutputBuffer(): void {
		if (this.terminalOutputBuffer.length === 0) {
			return;
		}
		const aggregated = this.terminalOutputBuffer.join('');
		const out = normalizeTerminalOutput(aggregated);
		let cleaned = cleanText(out);
		
		const tokens = estimateTokens(cleaned);
		if (tokens > MAX_TOKENS_PER_TERMINAL_OUTPUT) {
			const maxChars = MAX_TOKENS_PER_TERMINAL_OUTPUT * 4;
			cleaned = cleaned.slice(0, maxChars) + '
... [truncated]';
		}
		
		if (cleaned.trim()) {
			this.appendMessage({
				from: 'User',
				value: `<stdout>
${cleaned}
</stdout>`,
			});
		}
		this.terminalOutputBuffer = [];
	}

	flushPendingEditForFile(targetFile: string): void {
		const beforeSnapshot = this.pendingEditsBefore.get(targetFile);
		if (beforeSnapshot === null || beforeSnapshot === undefined) {
			return;
		}
		const afterState = this.fileStates.get(targetFile) ?? '';
		if (beforeSnapshot.replace(/
+$/, '') === afterState.replace(/
+$/, '')) {
			this.pendingEditsBefore.set(targetFile, null);
			this.pendingEditRegions.set(targetFile, null);
			return;
		}

		const {
			startBefore,
			endBefore,
			startAfter,
			endAfter,
			replacementLines,
		} = computeChangedBlockLines(beforeSnapshot, afterState);

		const beforeTotalLines = beforeSnapshot.split(/
?
/).length;
		let sedCmd: string;

		if (endBefore < startBefore) {
			// Pure insertion
			const escapedLines = replacementLines.map(line => escapeSingleQuotesForSed(line));
			const sedPayload = escapedLines.join('
');
			if (startBefore <= Math.max(1, beforeTotalLines)) {
				sedCmd = `sed -i '${startBefore}i\\
${sedPayload}' ${targetFile}`;
			} else {
				sedCmd = `sed -i '$a\\
${sedPayload}' ${targetFile}`;
			}
		} else if (replacementLines.length === 0) {
			// Pure deletion
			sedCmd = `sed -i '${startBefore},${endBefore}d' ${targetFile}`;
		} else {
			// Replacement
			const escapedLines = replacementLines.map(line => escapeSingleQuotesForSed(line));
			const sedPayload = escapedLines.join('
');
			sedCmd = `sed -i '${startBefore},${endBefore}c\\
${sedPayload}' ${targetFile}`;
		}

		const totalLines = afterState.split(/
?
/).length;
		const center = Math.floor((startAfter + endAfter) / 2);
		const vp = serializeComputeViewport(totalLines, center, VIEWPORT_RADIUS);
		this.perFileViewport.set(targetFile, vp);

		this.maybeCaptureFileContents(targetFile, beforeSnapshot);

		const chainedCmd = `${sedCmd} && cat -n ${targetFile} | sed -n '${vp.start},${vp.end}p'`;
		this.appendMessage({
			from: 'Assistant',
			value: fencedBlock('bash', cleanText(chainedCmd)),
		});

		const viewportOutput = lineNumberedOutput(afterState, vp.start, vp.end);
		this.appendMessage({
			from: 'User',
			value: `<stdout>
${viewportOutput}
</stdout>`,
		});

		this.pendingEditsBefore.set(targetFile, null);
		this.pendingEditRegions.set(targetFile, null);
	}

	flushAllPendingEdits(): void {
		for (const fname of this.pendingEditsBefore.keys()) {
			this.flushPendingEditForFile(fname);
		}
	}

	handleTabEvent(filePath: string, textContent: string | null): void {
		this.flushAllPendingEdits();
		this.flushTerminalOutputBuffer();

		if (textContent !== null) {
			const content = textContent.replace(/\
/g, '
').replace(/\
/g, '
');
			this.fileStates.set(filePath, content);

			const cmd = `cat -n ${filePath}`;
			this.appendMessage({
				from: 'Assistant',
				value: fencedBlock('bash', cleanText(cmd)),
			});
			const output = lineNumberedOutput(content);
			this.appendMessage({
				from: 'User',
				value: `<stdout>
${output}
</stdout>`,
			});
			this.filesOpenedInConversation.add(filePath);
		} else {
			// File switch without content snapshot: show current viewport only
			const content = this.fileStates.get(filePath) ?? '';
			const totalLines = content.split(/
?
/).length;
			let vp = this.perFileViewport.get(filePath);
			if (!vp || vp.end === 0) {
				vp = serializeComputeViewport(totalLines, 1, VIEWPORT_RADIUS);
				this.perFileViewport.set(filePath, vp);
			}
			if (vp && vp.end >= vp.start) {
				this.maybeCaptureFileContents(filePath, content);
				const cmd = `cat -n ${filePath} | sed -n '${vp.start},${vp.end}p'`;
				this.appendMessage({
					from: 'Assistant',
					value: fencedBlock('bash', cleanText(cmd)),
				});
				const viewportOutput = lineNumberedOutput(content, vp.start, vp.end);
				this.appendMessage({
					from: 'User',
					value: `<stdout>
${viewportOutput}
</stdout>`,
				});
			}
		}
	}

	handleContentEvent(filePath: string, offset: number, length: number, newText: string): void {
		this.flushTerminalOutputBuffer();

		const before = this.fileStates.get(filePath) ?? '';
		const newTextStr = newText ?? '';

		// Approximate current edit region in line space
		const startLineCurrent = before.slice(0, offset).split('
').length;
		const deletedContent = before.slice(offset, offset + length);
		const linesAdded = (newTextStr.match(/
/g) || []).length;
		const linesDeleted = (deletedContent.match(/
/g) || []).length;
		const regionStart = startLineCurrent;
		const regionEnd = startLineCurrent + Math.max(linesAdded, linesDeleted, 0);

		// Flush pending edits if this edit is far from the pending region
		let currentRegion = this.pendingEditRegions.get(filePath);
		if (currentRegion !== null && currentRegion !== undefined) {
			const { start: rstart, end: rend } = currentRegion;
			if (regionStart < (rstart - COALESCE_RADIUS) || regionStart > (rend + COALESCE_RADIUS)) {
				this.flushPendingEditForFile(filePath);
				currentRegion = null;
			}
		}

		const after = applyChange(before, offset, length, newText);

		if (this.pendingEditsBefore.get(filePath) === null || this.pendingEditsBefore.get(filePath) === undefined) {
			this.pendingEditsBefore.set(filePath, before);
		}

		// Update/initialize region union
		if (currentRegion === null || currentRegion === undefined) {
			this.pendingEditRegions.set(filePath, { start: regionStart, end: Math.max(regionStart, regionEnd) });
		} else {
			const { start: rstart, end: rend } = currentRegion;
			this.pendingEditRegions.set(filePath, {
				start: Math.min(rstart, regionStart),
				end: Math.max(rend, regionEnd),
			});
		}

		this.fileStates.set(filePath, after);
	}

	handleSelectionEvent(filePath: string, offset: number): void {
		if (this.pendingEditsBefore.get(filePath) !== null && this.pendingEditsBefore.get(filePath) !== undefined) {
			return;
		}

		this.flushTerminalOutputBuffer();

		const content = this.fileStates.get(filePath) ?? '';
		const totalLines = content.split(/
?
/).length;
		const targetLine = content.slice(0, offset).split('
').length;

		let vp = this.perFileViewport.get(filePath);
		let shouldEmit = false;

		if (!vp || vp.end === 0) {
			vp = serializeComputeViewport(totalLines, targetLine, VIEWPORT_RADIUS);
			this.perFileViewport.set(filePath, vp);
			shouldEmit = true;
		} else {
			if (targetLine < vp.start || targetLine > vp.end) {
				vp = serializeComputeViewport(totalLines, targetLine, VIEWPORT_RADIUS);
				this.perFileViewport.set(filePath, vp);
				shouldEmit = true;
			}
		}

		if (shouldEmit && vp && vp.end >= vp.start) {
			this.maybeCaptureFileContents(filePath, content);
			const cmd = `cat -n ${filePath} | sed -n '${vp.start},${vp.end}p'`;
			this.appendMessage({
				from: 'Assistant',
				value: fencedBlock('bash', cleanText(cmd)),
			});
			const viewportOutput = lineNumberedOutput(content, vp.start, vp.end);
			this.appendMessage({
				from: 'User',
				value: `<stdout>
${viewportOutput}
</stdout>`,
			});
		}
	}

	handleTerminalCommandEvent(command: string): void {
		this.flushAllPendingEdits();
		this.flushTerminalOutputBuffer();

		const commandStr = command.replace(/\
/g, '
').replace(/\
/g, '
');
		this.appendMessage({
			from: 'Assistant',
			value: fencedBlock('bash', cleanText(commandStr)),
		});
	}

	handleTerminalOutputEvent(output: string): void {
		const rawOutput = output.replace(/\
/g, '
').replace(/\
/g, '
');
		this.terminalOutputBuffer.push(rawOutput);
	}

	handleTerminalFocusEvent(): void {
		this.flushAllPendingEdits();
		this.flushTerminalOutputBuffer();
		// No-op for bash transcript; focus changes don't emit commands/output
	}

	handleGitBranchCheckoutEvent(branchInfo: string): void {
		this.flushAllPendingEdits();
		this.flushTerminalOutputBuffer();

		const branchStr = branchInfo.replace(/\
/g, '
').replace(/\
/g, '
');
		const cleaned = cleanText(branchStr);
		const m = cleaned.match(/to '([^']+)'/);
		if (!m) {
			console.warn(`[crowd-pilot] Could not extract branch name from git checkout message: ${cleaned}`);
			return;
		}
		let branchName = m[1].trim();
		// Safe-quote branch if it contains special characters
		if (/[^A-Za-z0-9._/\\-]/.test(branchName)) {
			branchName = "'" + branchName.replace(/'/g, "'\"'\"'") + "'";
		}
		const cmd = `git checkout ${branchName}`;
		this.appendMessage({
			from: 'Assistant',
			value: fencedBlock('bash', cleanText(cmd)),
		});
	}

	// Finalize and get conversation ready for model
	finalizeForModel(): ConversationMessage[] {
		this.flushAllPendingEdits();
		this.flushTerminalOutputBuffer();
		return this.getMessages();
	}
}

// Global conversation state manager instance
const conversationManager = new ConversationStateManager();

// Track activated files (files whose content we've captured)
const activatedFiles = new Set<string>();

/**
 * Clear all conversation context - resets the conversation manager and activated files.
 * Call this to start fresh without accumulated history.
 */
function clearContext(): void {
	conversationManager.reset();
	activatedFiles.clear();
	console.log('[crowd-pilot] Context cleared');
}

let suggestionsEnabled = true;
let statusBarItem: vscode.StatusBarItem | undefined;

function updateStatusBarItem(): void {
	if (!statusBarItem) { return; }
	if (suggestionsEnabled) {
		statusBarItem.text = '$(lightbulb) crowd-pilot';
		statusBarItem.tooltip = 'crowd-pilot: Tab suggestions enabled (click to disable)';
		statusBarItem.backgroundColor = undefined;
	} else {
		statusBarItem.text = '$(lightbulb-autofix) crowd-pilot';
		statusBarItem.tooltip = 'crowd-pilot: Tab suggestions disabled (click to enable)';
		statusBarItem.backgroundColor = new vscode.ThemeColor('statusBarItem.warningBackground');
	}
}

export function activate(context: vscode.ExtensionContext) {

	console.log('[crowd-pilot] Extension activated');

	(async () => {
		const config = vscode.workspace.getConfiguration('terminal.integrated');
		const commandsToSkipShell = config.get<string[]>('commandsToSkipShell', []);
		let updated = false;
		if (!commandsToSkipShell.includes('crowd-pilot.modelRun')) {
			commandsToSkipShell.push('crowd-pilot.modelRun');
			updated = true;
		}
		if (!commandsToSkipShell.includes('crowd-pilot.hideUi')) {
			commandsToSkipShell.push('crowd-pilot.hideUi');
			updated = true;
		}
		if (updated) {
			await config.update('commandsToSkipShell', commandsToSkipShell, vscode.ConfigurationTarget.Global);
		}
	})().catch((err) => console.error('[crowd-pilot] Startup initialization error:', err));

	statusBarItem = vscode.window.createStatusBarItem(vscode.StatusBarAlignment.Right, 100);
	statusBarItem.command = 'crowd-pilot.toggleSuggestions';
	updateStatusBarItem();
	statusBarItem.show();
	context.subscriptions.push(statusBarItem);

	const toggleSuggestions = vscode.commands.registerCommand('crowd-pilot.toggleSuggestions', () => {
		suggestionsEnabled = !suggestionsEnabled;
		updateStatusBarItem();
		if (!suggestionsEnabled) {
			hidePreviewUI(true);
		}
		vscode.window.showInformationMessage(
			suggestionsEnabled 
				? '[crowd-pilot]: Tab suggestions enabled' 
				: '[crowd-pilot]: Tab suggestions disabled'
		);
	});

	const hideUi = vscode.commands.registerCommand('crowd-pilot.hideUi', () => {
		recordPreferenceOutcome('rejected');
		hidePreviewUI(true);
	});

	const clearContextCmd = vscode.commands.registerCommand('crowd-pilot.clearContext', () => {
		clearContext();
		vscode.window.showInformationMessage('[crowd-pilot]: Context cleared');
	});

	const openPreferenceLogCmd = vscode.commands.registerCommand('crowd-pilot.openPreferenceLog', async () => {
		const logPath = getPreferenceLogPath();
		try {
			const uri = vscode.Uri.file(logPath);
			await vscode.window.showTextDocument(uri);
		} catch (err: any) {
			if (err.code === 'ENOENT' || err.message?.includes('ENOENT')) {
				vscode.window.showInformationMessage('[crowd-pilot] No preference log file exists yet. Accept or reject some suggestions first.');
			} else {
				vscode.window.showErrorMessage(`[crowd-pilot] Error opening preference log: ${err.message}`);
			}
		}
	});

	const modelRun = vscode.commands.registerCommand('crowd-pilot.modelRun', async () => {
		const editor = vscode.window.activeTextEditor;
		if (!editor) {
			return;
		}
		try {
			if (!previewVisible) { return; }
			let action: Action | undefined = currentAction;
			if (!action) {
				const single = await requestModelActions(editor);
				currentAction = single;
				action = single;
			}
			if (!action) {
				hidePreviewUI();
				return;
			}
			recordPreferenceOutcome('accepted');
			hidePreviewUI(false);
			await executeAction(action);
			autoShowNextAction();
		} catch (err) {
			const errorMessage = err instanceof Error ? err.message : String(err);
			vscode.window.showErrorMessage(`Model run failed: ${errorMessage}`);
		}
	});

	const sglangTest = vscode.commands.registerCommand('crowd-pilot.sglangTest', async () => {
		try {
			await callSGLangChat();
		} catch (err) {
			const errorMessage = err instanceof Error ? err.message : String(err);
			vscode.window.showErrorMessage(`SGLang test failed: ${errorMessage}`);
		}
	});

	const onSelChange = vscode.window.onDidChangeTextEditorSelection((e) => {
		if (e.textEditor === vscode.window.activeTextEditor) {
			suppressAutoPreview = false;
			schedulePredictionRefresh(true, false);

			const editor = e.textEditor;
			const selection = e.selections[0];
			if (selection) {
				const filePath = editor.document.uri.fsPath;
				const offset = editor.document.offsetAt(selection.start);
				conversationManager.handleSelectionEvent(filePath, offset);
			}
		}
	});

	const onActiveChange = vscode.window.onDidChangeActiveTextEditor((editor) => {
		suppressAutoPreview = false;
		schedulePredictionRefresh(true, false);

		if (editor) {
			const filePath = editor.document.uri.fsPath;
			const currentFileUri = editor.document.uri.toString();
			let tabEventText: string | null = null;

			if (!activatedFiles.has(currentFileUri)) {
				tabEventText = editor.document.getText();
				activatedFiles.add(currentFileUri);
			}

			conversationManager.handleTabEvent(filePath, tabEventText);
		}
	});

	const onDocChange = vscode.workspace.onDidChangeTextDocument((e) => {
		if (vscode.window.activeTextEditor?.document === e.document) {
			suppressAutoPreview = false;
			schedulePredictionRefresh(true, false);

			const filePath = e.document.uri.fsPath;
			for (const change of e.contentChanges) {
				const offset = change.rangeOffset;
				const length = change.rangeLength;
				const newText = change.text;
				conversationManager.handleContentEvent(filePath, offset, length, newText);
			}
		}
	});

	// Terminal focus event
	const onTerminalChange = vscode.window.onDidChangeActiveTerminal((terminal) => {
		if (terminal) {
			conversationManager.handleTerminalFocusEvent();
		}
	});

	// Terminal command execution event
	const onTerminalCommand = vscode.window.onDidStartTerminalShellExecution(async (event) => {
		const commandLine = event.execution.commandLine.value;
		conversationManager.handleTerminalCommandEvent(commandLine);

		// Capture terminal output
		const stream = event.execution.read();
		for await (const data of stream) {
			conversationManager.handleTerminalOutputEvent(data);
		}
	});

	context.subscriptions.push(
		toggleSuggestions,
		hideUi,
		clearContextCmd,
		openPreferenceLogCmd,
		sglangTest,
		modelRun,
		onSelChange,
		onActiveChange,
		onDocChange,
		onTerminalChange,
		onTerminalCommand
	);

	// Initialize: capture current active editor if any
	const initialEditor = vscode.window.activeTextEditor;
	if (initialEditor) {
		const filePath = initialEditor.document.uri.fsPath;
		const currentFileUri = initialEditor.document.uri.toString();
		const tabEventText = initialEditor.document.getText();
		activatedFiles.add(currentFileUri);
		conversationManager.handleTabEvent(filePath, tabEventText);
	}
}

export function deactivate() {}

// -------------------- Execution --------------------
let currentAction: Action | undefined;

function getActiveOrCreateTerminal(): vscode.Terminal {
	if (vscode.window.activeTerminal) {
		return vscode.window.activeTerminal;
	}
	return vscode.window.createTerminal('crowd-pilot');
}

async function executeAction(action: Action): Promise<void> {
	const editor = vscode.window.activeTextEditor;
	if (!editor) { return; }
	const doc = editor.document;
	if (action.kind === 'showTextDocument') {
		await vscode.window.showTextDocument(doc);
		return;
	}
	if (action.kind === 'setSelections') {
		editor.selections = action.selections.map(s => new vscode.Selection(
			new vscode.Position(s.start[0], s.start[1]),
			new vscode.Position(s.end[0], s.end[1])
		));
		editor.revealRange(editor.selections[0], vscode.TextEditorRevealType.InCenterIfOutsideViewport);
		return;
	}
	if (action.kind === 'editInsert') {
		await editor.edit((e: vscode.TextEditorEdit) => e.insert(new vscode.Position(action.position[0], action.position[1]), action.text));
		return;
	}
	if (action.kind === 'editDelete') {
		const range = new vscode.Range(
			new vscode.Position(action.range.start[0], action.range.start[1]),
			new vscode.Position(action.range.end[0], action.range.end[1])
		);
		await editor.edit((e: vscode.TextEditorEdit) => e.delete(range));
		return;
	}
	if (action.kind === 'editReplace') {
		const range = new vscode.Range(
			new vscode.Position(action.range.start[0], action.range.start[1]),
			new vscode.Position(action.range.end[0], action.range.end[1])
		);
		await editor.edit((e: vscode.TextEditorEdit) => e.replace(range, action.text));
		return;
	}
	if (action.kind === 'terminalShow') {
		const term = getActiveOrCreateTerminal();
		term.show();
		return;
	}
	if (action.kind === 'terminalSendText') {
		const term = getActiveOrCreateTerminal();
		term.show();
		term.sendText(action.text, false);
		return;
	}
	if (action.kind === 'openFile') {
		const uri = vscode.Uri.file(action.filePath);
		const openedEditor = await vscode.window.showTextDocument(uri);
		if (action.selections) {
			openedEditor.selections = action.selections.map(s => new vscode.Selection(
				new vscode.Position(s.start[0], s.start[1]),
				new vscode.Position(s.end[0], s.end[1])
			));
			openedEditor.revealRange(openedEditor.selections[0], vscode.TextEditorRevealType.InCenterIfOutsideViewport);
		}
		return;
	}
}

// -------------------- UI State & Helpers --------------------
const UI_CONTEXT_KEY = 'crowdPilot.uiVisible';
let previewVisible = false;
let decorationDeleteType: vscode.TextEditorDecorationType | undefined;
let decorationReplaceType: vscode.TextEditorDecorationType | undefined;
let decorationReplaceBlockType: vscode.TextEditorDecorationType | undefined;
let mockStep = 0;
let suppressAutoPreview = false;
let latestRequestId = 0;
let currentAbortController: AbortController | undefined;

const PREDICTION_DEBOUNCE_MS = 150;
const PREDICTION_THROTTLE_MS = 300;

type PendingPrediction = { id: number; timer: NodeJS.Timeout };

let nextQueuedPredictionId = 0;
let pendingPredictions: PendingPrediction[] = [];
const cancelledPredictionIds = new Set<number>();
let lastPredictionTimestamp: number | undefined;

function disposePreviewDecorations() {
	try { decorationDeleteType?.dispose(); } catch {}
	try { decorationReplaceType?.dispose(); } catch {}
	try { decorationReplaceBlockType?.dispose(); } catch {}
	decorationDeleteType = undefined;
	decorationReplaceType = undefined;
	decorationReplaceBlockType = undefined;
}

function getDynamicMargin(editor: vscode.TextEditor, anchorLine: number, text: string): string {
	const lines = text.split(/
?
/);
	const height = lines.length;
	
	// We need to check the document lines that will be covered by this panel.
	// The panel starts at 'anchorLine' and extends downwards by 'height' lines.
	// However, visually, since it's 'after', it sits to the right of 'anchorLine',
	// and then flows down.
	// So we check document lines from anchorLine to anchorLine + height - 1.
	
	const doc = editor.document;
	let maxLen = 0;
	const startLine = anchorLine;
	const endLine = Math.min(doc.lineCount - 1, anchorLine + height - 1);
	
	for (let i = startLine; i <= endLine; i++) {
		const lineText = doc.lineAt(i).text;
		const len = lineText.replace(/	/g, '    ').length;
		if (len > maxLen) {
			maxLen = len;
		}
	}
	
	const anchorLineText = doc.lineAt(anchorLine).text;
	const anchorLen = anchorLineText.replace(/	/g, '    ').length;
	
	const diff = Math.max(0, maxLen - anchorLen);
	const margin = diff + 4; 
	return `${margin}ch`;
}

function showPreviewUI(action: Action): void {
	const editor = vscode.window.activeTextEditor;
	if (!editor) { return; }
	disposePreviewDecorations();

	const next = (action.kind === 'editInsert' || action.kind === 'editDelete' || action.kind === 'editReplace' || action.kind === 'terminalSendText' || action.kind === 'setSelections' || action.kind === 'openFile') ? action : undefined;
	if (!next) {
		previewVisible = false;
		vscode.commands.executeCommand('setContext', UI_CONTEXT_KEY, false);
		currentAction = action;
		return;
	}

	const trimText = (t: string) => {
		const oneLine = t.replace(/
?
/g, '\
');
		return oneLine.length > 80 ? oneLine.slice(0, 77) + '…' : oneLine;
	};

	if (next.kind === 'setSelections') {
		const selection = next.selections[0];
		const targetPos = new vscode.Position(selection.start[0], selection.start[1]);
		const isVisible = editor.visibleRanges.some(r => r.contains(targetPos));
		
		let anchorPos = targetPos;
		let label = "↳ Move Cursor Here";

		if (!isVisible && editor.visibleRanges.length > 0) {
			const firstVisible = editor.visibleRanges[0].start;
			const lastVisible = editor.visibleRanges[editor.visibleRanges.length - 1].end;
			
			if (targetPos.isBefore(firstVisible)) {
				anchorPos = new vscode.Position(firstVisible.line, Number.MAX_VALUE);
			} else {
				anchorPos = new vscode.Position(lastVisible.line, Number.MAX_VALUE);
			}

			if (targetPos.line < anchorPos.line) {
				label = `↑ Move Cursor to Line ${targetPos.line + 1}`;
			} else {
				label = `↓ Move Cursor to Line ${targetPos.line + 1}`;
			}
		}

		const margin = getDynamicMargin(editor, anchorPos.line, label);

		decorationReplaceBlockType = vscode.window.createTextEditorDecorationType({
			after: {
				contentText: '',
				color: new vscode.ThemeColor('charts.purple'),
				backgroundColor: new vscode.ThemeColor('editor.background'),
				fontStyle: 'italic',
				fontWeight: '600',
				margin: `0 0 0 ${margin}`,
				textDecoration: `none; display: inline-block; white-space: pre; content: "${label}"; border: 1px solid var(--vscode-charts-purple); padding: 4px; border-radius: 4px; box-shadow: 0 4px 8px rgba(0,0,0,0.25); pointer-events: none; position: relative; z-index: 100; vertical-align: top;`
			}
		});
		editor.setDecorations(decorationReplaceBlockType, [{ range: new vscode.Range(anchorPos, anchorPos) }]);
	} else if (next.kind === 'terminalSendText') {
		const cursor = editor.selection.active;
		const isVisible = editor.visibleRanges.some(r => r.contains(cursor));
		
		let anchorPos = new vscode.Position(cursor.line, Number.MAX_VALUE);
		
		if (!isVisible && editor.visibleRanges.length > 0) {
			const firstVisible = editor.visibleRanges[0].start;
			const lastVisible = editor.visibleRanges[editor.visibleRanges.length - 1].end;
			
			if (cursor.isBefore(firstVisible)) {
				anchorPos = new vscode.Position(firstVisible.line, Number.MAX_VALUE);
			} else {
				anchorPos = new vscode.Position(lastVisible.line, Number.MAX_VALUE);
			}
		}
		
		const summary = trimText(next.text || '');
		const label = `↳ Execute shell command in terminal: ${summary}`;
		const margin = getDynamicMargin(editor, anchorPos.line, label);

		decorationReplaceBlockType = vscode.window.createTextEditorDecorationType({
			after: {
				contentText: '',
				color: new vscode.ThemeColor('charts.purple'),
				backgroundColor: new vscode.ThemeColor('editor.background'),
				fontStyle: 'italic',
				fontWeight: '600',
				margin: `0 0 0 ${margin}`,
				textDecoration: `none; display: inline-block; white-space: pre; content: "${label.replace(/"/g, '\\"')}"; border: 1px solid var(--vscode-charts-purple); padding: 4px; border-radius: 4px; box-shadow: 0 4px 8px rgba(0,0,0,0.25); pointer-events: none; position: relative; z-index: 100; vertical-align: top;`
			}
		});
		editor.setDecorations(decorationReplaceBlockType, [{ range: new vscode.Range(anchorPos, anchorPos) }]);
	} else if (next.kind === 'editInsert') {
		const posLine = next.position[0];
		const fullBlock = next.text;
		const cssContent = fullBlock
			.replace(/"/g, '\\"')
			.replace(/
?
/g, '\\A ');

		const docLineCount = editor.document.lineCount;
		let anchorLine = posLine;
		let shiftUp = true;
		
		if (anchorLine >= docLineCount) {
			anchorLine = docLineCount - 1;
			shiftUp = false;
		}

		const anchorPos = new vscode.Position(anchorLine, Number.MAX_VALUE); 
		
		const marginCheckLine = anchorLine;
		const margin = getDynamicMargin(editor, marginCheckLine, fullBlock);

		const topOffset = '0';

		const beforeDecoration = {
			contentText: '',
			textDecoration: `none; position: absolute; left: 0; width: 100vw; border-top: 1px dashed var(--vscode-charts-purple); top: 0; height: 0; z-index: 99; pointer-events: none;`
		};

		decorationReplaceBlockType = vscode.window.createTextEditorDecorationType({
			before: beforeDecoration,
			after: {
				contentText: '',
				color: new vscode.ThemeColor('charts.purple'),
				backgroundColor: new vscode.ThemeColor('editor.background'),
				fontStyle: 'italic',
				fontWeight: '600',
				margin: `0 0 0 ${margin}`,
				textDecoration: `none; display: inline-block; white-space: pre; content: "${cssContent}"; border: 1px solid var(--vscode-charts-purple); padding: 4px; border-radius: 4px; box-shadow: 0 4px 8px rgba(0,0,0,0.25); pointer-events: none; position: relative; z-index: 100; vertical-align: top; top: ${topOffset};`
			}
		});
		editor.setDecorations(decorationReplaceBlockType, [{ range: new vscode.Range(anchorPos, anchorPos) }]);
	} else if (next.kind === 'editDelete') {
		const range = new vscode.Range(
			new vscode.Position(next.range.start[0], next.range.start[1]),
			new vscode.Position(next.range.end[0], next.range.end[1])
		);
		decorationDeleteType = vscode.window.createTextEditorDecorationType({
			backgroundColor: 'rgba(255, 60, 60, 0.18)',
			border: '1px solid rgba(255, 60, 60, 0.35)',
			textDecoration: 'line-through'
		});
		editor.setDecorations(decorationDeleteType, [{ range }]);
	} else if (next.kind === 'editReplace') {
		const range = new vscode.Range(
			new vscode.Position(next.range.start[0], next.range.start[1]),
			new vscode.Position(next.range.end[0], next.range.end[1])
		);
		decorationReplaceType = vscode.window.createTextEditorDecorationType({
			backgroundColor: 'rgba(255,165,0,0.15)',
			border: '1px dashed rgba(255,165,0,0.45)',
			color: new vscode.ThemeColor('disabledForeground'),
			textDecoration: 'line-through'
		});
		editor.setDecorations(decorationReplaceType, [{ range }]);

		const fullBlock = next.text;
		
		const cssContent = fullBlock
			.replace(/"/g, '\\"')
			.replace(/
?
/g, '\\A '); 

		const anchorLine = range.start.line;
		const anchorPos = new vscode.Position(anchorLine, Number.MAX_VALUE);
		const margin = getDynamicMargin(editor, anchorLine, fullBlock);

		decorationReplaceBlockType = vscode.window.createTextEditorDecorationType({
			after: {
				contentText: '',
				color: new vscode.ThemeColor('charts.purple'),
				backgroundColor: new vscode.ThemeColor('editor.background'),
				fontStyle: 'italic',
				fontWeight: '600',
				margin: `0 0 0 ${margin}`,
				textDecoration: `none; display: inline-block; white-space: pre; content: "${cssContent}"; border: 1px solid var(--vscode-charts-purple); padding: 4px; border-radius: 4px; box-shadow: 0 4px 8px rgba(0,0,0,0.25); pointer-events: none; position: relative; z-index: 100; vertical-align: top;`
			}
		});
		editor.setDecorations(decorationReplaceBlockType, [{ range: new vscode.Range(anchorPos, anchorPos) }]);
	} else if (next.kind === 'openFile') {
		const cursor = editor.selection.active;
		const isVisible = editor.visibleRanges.some(r => r.contains(cursor));
		
		let anchorPos = new vscode.Position(cursor.line, Number.MAX_VALUE);
		
		if (!isVisible && editor.visibleRanges.length > 0) {
			const firstVisible = editor.visibleRanges[0].start;
			const lastVisible = editor.visibleRanges[editor.visibleRanges.length - 1].end;
			
			if (cursor.isBefore(firstVisible)) {
				anchorPos = new vscode.Position(firstVisible.line, Number.MAX_VALUE);
			} else {
				anchorPos = new vscode.Position(lastVisible.line, Number.MAX_VALUE);
			}
		}
		
		const fileName = next.filePath.split(/[/\\]/).pop() || next.filePath;
		const targetLine = next.selections?.[0]?.start[0];
		const label = targetLine !== undefined
			? `↳ Switch to file: ${fileName}:${targetLine + 1}` // Display as 1-based
			: `↳ Switch to file: ${fileName}`;
		const margin = getDynamicMargin(editor, anchorPos.line, label);

		decorationReplaceBlockType = vscode.window.createTextEditorDecorationType({
			after: {
				contentText: '',
				color: new vscode.ThemeColor('charts.purple'),
				backgroundColor: new vscode.ThemeColor('editor.background'),
				fontStyle: 'italic',
				fontWeight: '600',
				margin: `0 0 0 ${margin}`,
				textDecoration: `none; display: inline-block; white-space: pre; content: "${label.replace(/"/g, '\\"')}"; border: 1px solid var(--vscode-charts-purple); padding: 4px; border-radius: 4px; box-shadow: 0 4px 8px rgba(0,0,0,0.25); pointer-events: none; position: relative; z-index: 100; vertical-align: top;`
			}
		});
		editor.setDecorations(decorationReplaceBlockType, [{ range: new vscode.Range(anchorPos, anchorPos) }]);
	}

	previewVisible = true;
	vscode.commands.executeCommand('setContext', UI_CONTEXT_KEY, true);
	currentAction = action;
}

function hidePreviewUI(suppress?: boolean): void {
	disposePreviewDecorations();
	previewVisible = false;
	vscode.commands.executeCommand('setContext', UI_CONTEXT_KEY, false);
	if (suppress) {
		suppressAutoPreview = true;
	}
}

/**
 * Schedule a model preview refresh, coalescing rapid editor events and
 * throttling how often we actually talk to the model.
 */
function schedulePredictionRefresh(debounce: boolean, userRequested: boolean): void {
	if (!suggestionsEnabled) {
		return;
	}
	if (!userRequested && suppressAutoPreview) {
		return;
	}

	const editor = vscode.window.activeTextEditor;
	if (!editor) {
		hidePreviewUI();
		return;
	}

	if (!userRequested) {
		if (!vscode.window.state.focused) {
			hidePreviewUI();
			return;
		}
		if (editor.document.getText().length === 0) {
			hidePreviewUI();
			return;
		}
	}

	const now = Date.now();
	const id = ++nextQueuedPredictionId;

	let delay = 0;
	if (debounce) {
		delay = Math.max(delay, PREDICTION_DEBOUNCE_MS);
	}
	if (lastPredictionTimestamp !== null && lastPredictionTimestamp !== undefined) {
		const elapsed = now - lastPredictionTimestamp;
		if (elapsed < PREDICTION_THROTTLE_MS) {
			delay = Math.max(delay, PREDICTION_THROTTLE_MS - elapsed);
		}
	}

	const timer = setTimeout(() => {
		if (cancelledPredictionIds.has(id)) {
			cancelledPredictionIds.delete(id);
			return;
		}

		lastPredictionTimestamp = Date.now();
		pendingPredictions = pendingPredictions.filter(p => p.id !== id);

		void autoShowNextAction();
	}, delay);

	pendingPredictions.push({ id, timer });

	if (pendingPredictions.length > 2) {
		const oldest = pendingPredictions.shift();
		if (oldest) {
			cancelledPredictionIds.add(oldest.id);
			clearTimeout(oldest.timer);
		}
	}
}

async function autoShowNextAction(): Promise<void> {
	if (suppressAutoPreview) { return; }
	const editor = vscode.window.activeTextEditor;
	if (!editor) { return; }
	try {
		currentAbortController?.abort();
		const controller = new AbortController();
		currentAbortController = controller;
		const requestId = ++latestRequestId;
		const next = await requestModelActions(editor, controller.signal);
		if (requestId !== latestRequestId) { return; }
		if (next) { showPreviewUI(next); } else { hidePreviewUI(); }
	} catch (err) {
		const e = err as any;
		const isAbort = e?.name === 'AbortError' || /aborted/i.test(String(e?.message ?? ''));
		if (isAbort) { return; }
		hidePreviewUI();
	}
}

// -------------------- SGLang Client (simple test) --------------------
async function callSGLangChat(): Promise<void> {
	const cfg = getConfig();
	const headers: any = {
		'Content-Type': 'application/json'
	};


	const requestBody: any = {
		model: cfg.modelName,
		messages: [
			{ role: 'user', content: 'What is the capital of France?' }
		]
	};
	requestBody.temperature = 0.7;
	requestBody.top_p = 0.8;
	requestBody.top_k = 20;
	requestBody.min_p = 0;
	requestBody.chat_template_kwargs = {
		enable_thinking: false
	};
	const postData = JSON.stringify(requestBody);
	headers['Content-Length'] = Buffer.byteLength(postData);

	const options = {
		hostname: cfg.hostname,
		port: cfg.port,
		path: cfg.basePath,
		method: 'POST',
		headers
	};


	try {
		const json = await new Promise<any>((resolve, reject) => {
			const req = http.request(options, (res: http.IncomingMessage) => {
				let data = '';
				res.on('data', (chunk: Buffer) => {
					data += chunk.toString();
				});
				res.on('end', () => {
					try {
						resolve(JSON.parse(data));
					} catch (err) {
						reject(new Error(`Failed to parse response: ${err instanceof Error ? err.message : String(err)}`));
					}
				});
			});

			req.on('error', (err: Error) => {
				reject(err);
			});

			req.write(postData);
			req.end();
		});

		vscode.window.showInformationMessage(`Response: ${JSON.stringify(json, null, 2)}`);
	} catch (err) {
		const errorMessage = err instanceof Error ? err.message : String(err);
		vscode.window.showErrorMessage(`Request failed: ${errorMessage}`);
	}
}

// -------------------- Model-planned Actions --------------------
async function requestModelActions(editor: vscode.TextEditor, signal?: AbortSignal): Promise<Action> {
	const cfg = getConfig();
	const headers: any = {
		'Content-Type': 'application/json'
	};

	const doc = editor.document;

	// FIXME (f.srambical): This should be the system prompt that was used during serialization.
	const systemPrompt = [
		'You are a helpful assistant that interacts with a computer shell to solve programming tasks.',
		'Your goal is to predict the next bash command a developer would most likely execute, given their editing and navigation history.',
		'',
		'=== CONVERSATION FORMAT ===',
		'The conversation history alternates between:',
		'- Assistant messages: bash commands in fenced code blocks',
		'- User messages: command output wrapped in <stdout>...</stdout> tags',
		'',
		'File contents are displayed with 6-character right-aligned line numbers followed by a tab, e.g.:',
		'     1	first line',
		'     2	second line',
		'',
		'File content is typically shown in viewports of ~20 lines around the area of interest.',
		'',
		'=== RESPONSE FORMAT ===',
		'Your response must contain exactly ONE bash code block with one command or two commands connected with &&.',
		'',
		'<format_example>',
		'```bash',
		'your_command_here',
		'```',
		'</format_example>',
		'',
		'Failure to follow these rules will cause your response to be rejected.',
		'',
		'=== EDIT COMMAND FORMAT (IMPORTANT) ===',
		'When you want to EDIT a file, you MUST encode the edit using line-based sed commands in ONE of the following forms,',
		'and you MUST NOT use substitution commands like "Ns/old/new/g".',
		'',
		'Assume all line numbers are 1-based and paths are absolute.',
		'Allowed edit encodings (choose exactly one per response):',
		'',
		'1) Replace a contiguous block of lines:',
		"   sed -i 'START,ENDc\\",
		'NEW_LINE_1',
		'NEW_LINE_2',
		"...",
		"' /abs/path/to/file && cat -n /abs/path/to/file | sed -n 'VSTART,VENDp'",
		'',
		'2) Delete a contiguous block of lines:',
		"   sed -i 'START,ENDd' /abs/path/to/file && cat -n /abs/path/to/file | sed -n 'VSTART,VENDp'",
		'',
		'3) Insert new lines BEFORE a given line:',
		"   sed -i 'STARTi\\",
		'NEW_LINE_1',
		'NEW_LINE_2',
		"...",
		"' /abs/path/to/file && cat -n /abs/path/to/file | sed -n 'VSTART,VENDp'",
		'',
		'4) Append new lines at the END of the file:',
		"   sed -i '$a\\",
		'NEW_LINE_1',
		'NEW_LINE_2',
		"...",
		"' /abs/path/to/file && cat -n /abs/path/to/file | sed -n 'VSTART,VENDp'",
		'',
		'Where VSTART and VEND specify a small viewport around the edited region.',
		'',
		'Do NOT emit commands like "3s/print/print()/g" or any other "s/old/new/" style sed substitution; instead,',
		'always rewrite the affected lines using one of the line-based forms above.',
		'',
		'When you are NOT editing files (e.g., running tests, git commands, tools, etc.), you may emit arbitrary bash commands.'
	].join('
');

	const accumulatedMessages = conversationManager.finalizeForModel();
	
	let conversationMessages: Array<{ role: 'system' | 'user' | 'assistant'; content: string }> = [
		{ role: 'system', content: systemPrompt },
	];
	
	for (const msg of accumulatedMessages) {
		const role = msg.from === 'User' ? 'user' : 'assistant';
		conversationMessages.push({ role, content: msg.value });
	}

	conversationMessages = truncateToContextLimit(conversationMessages, cfg.maxContextTokens);

	const requestBody: any = {
		model: cfg.modelName,
		messages: conversationMessages
	};
	requestBody.temperature = 0.7;
	requestBody.top_p = 0.8;
	requestBody.top_k = 20;
	requestBody.min_p = 0;
	requestBody.logprobs = true;
	requestBody.chat_template_kwargs = {
		enable_thinking: false
	};

	const postData = JSON.stringify(requestBody);
	headers['Content-Length'] = Buffer.byteLength(postData);

	const options: any = {
		hostname: cfg.hostname,
		port: cfg.port,
		path: cfg.basePath,
		method: 'POST',
		headers
	};
	if (signal) {
		options.signal = signal;
	}

	const json = await new Promise<any>((resolve, reject) => {
		const req = http.request(options, (res: http.IncomingMessage) => {
			let data = '';
			res.on('data', (chunk: Buffer) => { data += chunk.toString(); });
			res.on('end', () => {
				try {
					resolve(JSON.parse(data));
				} catch (err) {
					reject(new Error(`Failed to parse response: ${err instanceof Error ? err.message : String(err)}`));
				}
			});
		});
		req.on('error', (err: Error) => reject(err));
		req.write(postData);
		req.end();
	});

	const avgLogprob = calculateAverageLogprob(json);
	if (avgLogprob < cfg.minAvgLogprob) {
		return undefined as any; // Low confidence, silently skip suggestion
	}

	const content = extractChatContent(json);
	if (typeof content !== 'string' || content.trim().length === 0) {
		throw new Error('Empty model content');
	}
	const action = parseAction(content, doc);
	if (!action) {
		throw new Error('No valid action parsed from model output');
	}

	markPendingAsIgnored();

	createPendingPreferenceSample(
		conversationMessages,
		content,
		action,
		avgLogprob,
		cfg.modelName
	);

	return action;
}

function extractChatContent(json: any): string | undefined {
	try {
		if (json && Array.isArray(json.choices) && json.choices[0]) {
			const choice = json.choices[0];
			if (choice.message && typeof choice.message.content === 'string') {
				return choice.message.content;
			}
			if (typeof choice.text === 'string') {
				return choice.text;
			}
		}
		return undefined;
	} catch {
		return undefined;
	}
}

/**
 * Calculate average logprob per token from the API response.
 * Returns the mean of logprobs across all tokens (negative value, closer to 0 = more confident).
 * Returns -Infinity if logprobs are not available.
 */
function calculateAverageLogprob(json: any): number {
	const logprobs = json.choices[0]?.logprobs;
	const sum = logprobs.content.reduce((s: number, t: any) => s + t.logprob, 0);
	return sum / logprobs.content.length;
}

function parseAction(raw: string, doc?: vscode.TextDocument): Action | undefined {
	const command = extractBashCommand(raw);
	if (!command) {
		return undefined;
	}
	const normalized = command.replace(/<think>[\s\S]*?<\/think>/gi, '').trim();
	if (!normalized) {
		return undefined;
	}
	if (doc) {
		const editAction = parseEditFromSedCommand(normalized, doc);
		if (editAction) {
			return editAction;
		}
		const viewportAction = parseViewportFromCatCommand(normalized, doc);
		if (viewportAction) {
			return viewportAction;
		}
	}
	return { kind: 'terminalSendText', text: normalized };
}

/**
 * Parse a sed-based edit command of the form emitted by the NeMo serializer into a VS Code edit action.
 *
 * Supported patterns (1-based line numbers, mirroring serialization_utils.py):
 *   sed -i 'START,ENDc
<replacement...>' <file>     -> editReplace
 *   sed -i 'START,ENDd' <file>                      -> editDelete
 *   sed -i 'STARTi
<insert...>' <file>             -> editInsert (before START)
 *   sed -i '$a
<append...>' <file>                 -> editInsert (append at EOF)
 *
 * If the command does not match these patterns, returns undefined.
 */
function parseEditFromSedCommand(command: string, doc: vscode.TextDocument): Action | undefined {
	// Only consider the first command before && / ||, since cat -n etc. are for viewport only.
	const main = command.split(/&&|\|\|/)[0]?.trim() ?? '';
	if (!main) {
		return undefined;
	}

	// Match: sed -i '<script>' <file>
	const sedMatch = main.match(/sed\s+-i\s+'([\s\S]*?)'\s+([^\s&|]+)\s*$/);
	if (!sedMatch) {
		return undefined;
	}
	const script = sedMatch[1] ?? '';
	const targetFile = sedMatch[2] ?? '';
	const activePath = doc.uri.fsPath;
	if (targetFile !== activePath) {
		return undefined;
	}

	// Delete: "START,ENDd"
	const deleteMatch = script.match(/^(\d+),(\d+)d$/);
	if (deleteMatch) {
		const startLine1 = Number(deleteMatch[1]);
		const endLine1 = Number(deleteMatch[2]);
		if (!Number.isFinite(startLine1) || !Number.isFinite(endLine1)) {
			return undefined;
		}
		const startLine0 = Math.max(0, startLine1 - 1);
		const endLine0 = Math.max(0, endLine1 - 1);

		let endPosLine = endLine0 + 1;
		let endPosChar = 0;
		if (endPosLine >= doc.lineCount) {
			endPosLine = doc.lineCount - 1;
			endPosChar = doc.lineAt(endPosLine).range.end.character;
		}
		return {
			kind: 'editDelete',
			range: {
				start: [startLine0, 0],
				end: [endPosLine, endPosChar],
			},
		};
	}

	// Replace: "START,ENDc
ewline<payload...>"
	const replaceMatch = script.match(/^(\d+),(\d+)c\\
([\s\S]*)$/);
	if (replaceMatch) {
		const startLine1 = Number(replaceMatch[1]);
		const endLine1 = Number(replaceMatch[2]);
		let payload = replaceMatch[3] ?? '';
		if (!Number.isFinite(startLine1) || !Number.isFinite(endLine1)) {
			return undefined;
		}
		payload = payload.replace(/'\"'\"'/g, "'");
		// Convert escape sequences to actual characters
		payload = payload.replace(/\
/g, '
').replace(/\	/g, '	').replace(/\\'/g, "'").replace(/\\\\/g, '\\');
		const startLine0 = Math.max(0, startLine1 - 1);
		const endLine0 = Math.max(0, endLine1 - 1);
		const startPos: [number, number] = [startLine0, 0];

		let endPosLine = endLine0 + 1;
		let endPosChar = 0;
		if (endPosLine >= doc.lineCount) {
			endPosLine = doc.lineCount - 1;
			endPosChar = doc.lineAt(endPosLine).range.end.character;
		}

		const text = payload.endsWith('
') ? payload : payload + '
';
		return {
			kind: 'editReplace',
			range: { start: startPos, end: [endPosLine, endPosChar] },
			text,
		};
	}

	const insertMatch = script.match(/^(\d+)i\\
([\s\S]*)$/);
	if (insertMatch) {
		const line1 = Number(insertMatch[1]);
		let payload = insertMatch[2] ?? '';
		if (!Number.isFinite(line1)) {
			return undefined;
		}
		payload = payload.replace(/'\"'\"'/g, "'");
		// Convert escape sequences to actual characters
		payload = payload.replace(/\
/g, '
').replace(/\	/g, '	').replace(/\\'/g, "'").replace(/\\\\/g, '\\');
		const insertLine0 = Math.max(0, line1 - 1);
		const position: [number, number] = [insertLine0, 0];
		const text = payload.endsWith('
') ? payload : payload + '
';
		return {
			kind: 'editInsert',
			position,
			text,
		};
	}

	const appendMatch = script.match(/^\$a\\
([\s\S]*)$/);
	if (appendMatch) {
		let payload = appendMatch[1] ?? '';
		payload = payload.replace(/'\"'\"'/g, "'");
		// Convert escape sequences to actual characters
		payload = payload.replace(/\
/g, '
').replace(/\	/g, '	').replace(/\\'/g, "'").replace(/\\\\/g, '\\');
		const insertLine0 = doc.lineCount;
		const position: [number, number] = [insertLine0, 0];
		const needsLeadingNewline = doc.lineCount > 0;
		const base = payload.endsWith('
') ? payload : payload + '
';
		const text = needsLeadingNewline ? '
' + base : base;
		return {
			kind: 'editInsert',
			position,
			text,
		};
	}

	return undefined;
}

/**
 * Parse viewport / selection commands of the form:
 *   cat -n <file> | sed -n 'START,ENDp'
 *
 * into a lightweight VS Code selection move (setSelections). This mirrors how
 * selection and viewport events are serialized in serialization_utils.py.
 */
function parseViewportFromCatCommand(command: string, doc: vscode.TextDocument): Action | undefined {
	const main = command.split(/&&|\|\|/)[0]?.trim() ?? '';
	if (!main) {
		return undefined;
	}

	// Simple file-open: cat -n <file>
	const simpleCatMatch = main.match(/^cat\s+-n\s+([^\s|]+)\s*$/);
	if (simpleCatMatch) {
		const targetFile = simpleCatMatch[1] ?? '';
		if (targetFile !== doc.uri.fsPath) {
			return { kind: 'openFile', filePath: targetFile };
		}
		// Ensure the active document is visible; rely on existing editor to handle this.
		return { kind: 'showTextDocument' };
	}

	// Viewport slice: cat -n <file> | sed -n 'START,ENDp'
	const viewportMatch = main.match(/^cat\s+-n\s+([^\s|]+)\s*\|\s*sed\s+-n\s+'(\d+),(\d+)p'\s*$/);
	if (!viewportMatch) {
		return undefined;
	}

	const targetFile = viewportMatch[1] ?? '';
	const startStr = viewportMatch[2] ?? '';
	const endStr = viewportMatch[3] ?? '';

	const startLine1 = Number(startStr);
	const endLine1 = Number(endStr);

	// Place the cursor in the middle of the viewport (1-based to 0-based).
	const center1 = Math.floor((startLine1 + endLine1) / 2);
	const center0 = Math.max(0, center1 - 1);

	if (targetFile !== doc.uri.fsPath) {
		return {
			kind: 'openFile',
			filePath: targetFile,
			selections: [{ start: [center0, 0], end: [center0, 0] }]
		};
	}
	const lastLine = Math.max(0, doc.lineCount - 1);
	const line = Math.min(center0, lastLine);

	return {
		kind: 'setSelections',
		selections: [
			{
				start: [line, 0],
				end: [line, 0],
			},
		],
	};
}

function extractBashCommand(raw: string): string | undefined {
	if (!raw) {
		return undefined;
	}
	const trimmed = raw.trim();
	const fenceMatch = trimmed.match(/```(?:bash)?\s*([\s\S]*?)```/i);
	if (fenceMatch && fenceMatch[1]) {
		return fenceMatch[1];
	}
	// Fallback: treat entire response as the command
	return trimmed.length > 0 ? trimmed : undefined;
}