import { execFileSync } from "node:child_process";
import { copyToClipboard, CustomEditor, type ExtensionAPI, type ExtensionContext } from "@earendil-works/pi-coding-agent";
import { Key, matchesKey, truncateToWidth, visibleWidth } from "@earendil-works/pi-tui";

type Mode = "normal" | "insert" | "replace" | "visual" | "visual-line";
type Pending = "d" | "c" | "y" | "f" | "F" | "t" | "T" | "r" | undefined;
type LastFind = { char: string; forward: boolean; till: boolean } | undefined;
type Cursor = { line: number; col: number };
type CustomEditorArgs = ConstructorParameters<typeof CustomEditor>;

type InternalEditor = {
	state: {
		cursorLine: number;
		lines?: string[];
		cursorCol?: number;
	};
	setCursorCol(col: number): void;
	onChange?: (text: string) => void;
	preferredVisualCol?: number | null;
	historyIndex?: number;
	lastAction?: string | null;
	paddingX?: number;
	scrollOffset?: number;
	borderColor?: (text: string) => string;
	layoutText?: (contentWidth: number) => Array<{ text: string; hasCursor: boolean; cursorPos?: number }>;
};

type EditorSnapshot = {
	text: string;
	cursor: Cursor;
};

type ReplaceSessionEdit = {
	start: number;
	inserted: string;
	original: string;
};

const graphemeSegmenter = new Intl.Segmenter(undefined, { granularity: "grapheme" });

function clamp(value: number, min: number, max: number): number {
	return Math.max(min, Math.min(max, value));
}

function sanitizeStatusText(text: string): string {
	return text
		.replace(/[\r\n\t]/g, " ")
		.replace(/ +/g, " ")
		.trim();
}

function formatTokens(count: number): string {
	if (count < 1000) return count.toString();
	if (count < 10000) return `${(count / 1000).toFixed(1)}k`;
	if (count < 1000000) return `${Math.round(count / 1000)}k`;
	if (count < 10000000) return `${(count / 1000000).toFixed(1)}M`;
	return `${Math.round(count / 1000000)}M`;
}

function isWord(char: string | undefined): boolean {
	return !!char && /[A-Za-z0-9_]/.test(char);
}

function runClipboardCommand(command: string, args: readonly string[]): string | undefined {
	try {
		return execFileSync(command, args, {
			encoding: "utf8",
			stdio: ["ignore", "pipe", "ignore"],
			timeout: 2000,
		}).replace(/\r\n/g, "\n");
	} catch {
		return undefined;
	}
}

function readSystemClipboardText(): string | undefined {
	if (process.platform === "darwin") return runClipboardCommand("pbpaste", []);
	if (process.platform === "win32") {
		return runClipboardCommand("powershell", ["-NoProfile", "-Command", "Get-Clipboard -Raw"]);
	}
	if (process.env.TERMUX_VERSION) {
		const text = runClipboardCommand("termux-clipboard-get", []);
		if (text !== undefined) return text;
	}
	for (const [command, args] of [
		["wl-paste", ["-n"]],
		["xclip", ["-selection", "clipboard", "-o"]],
		["xsel", ["--clipboard", "--output"]],
	] as const) {
		const text = runClipboardCommand(command, args);
		if (text !== undefined) return text;
	}
	return undefined;
}

function isBigWord(char: string | undefined): boolean {
	return !!char && !/\s/.test(char);
}

function lineStart(text: string, offset: number): number {
	if (offset <= 0) return 0;
	const bounded = Math.min(offset, text.length);
	const index = text.lastIndexOf("\n", bounded - 1);
	return index === -1 ? 0 : index + 1;
}

function lineEnd(text: string, offset: number): number {
	const bounded = Math.min(Math.max(offset, 0), text.length);
	const index = text.indexOf("\n", bounded);
	return index === -1 ? text.length : index;
}

function lineLast(text: string, offset: number): number {
	const start = lineStart(text, offset);
	const end = lineEnd(text, offset);
	return end > start ? end - 1 : start;
}

function prevLineStart(text: string, offset: number): number | undefined {
	const start = lineStart(text, offset);
	if (start === 0) return undefined;
	return lineStart(text, start - 1);
}

function nextLineStart(text: string, offset: number): number | undefined {
	const end = lineEnd(text, offset);
	if (end >= text.length) return undefined;
	return end + 1;
}

function moveUp(text: string, offset: number): number {
	const currentStart = lineStart(text, offset);
	const targetStart = prevLineStart(text, offset);
	if (targetStart === undefined) return offset;
	const targetLast = lineLast(text, targetStart);
	const col = offset - currentStart;
	return Math.min(targetStart + col, targetLast);
}

function moveDown(text: string, offset: number): number {
	const currentStart = lineStart(text, offset);
	const targetStart = nextLineStart(text, offset);
	if (targetStart === undefined) return offset;
	const targetLast = lineLast(text, targetStart);
	const col = offset - currentStart;
	return Math.min(targetStart + col, targetLast);
}

function nextWordStart(text: string, offset: number, big: boolean): number {
	const match = big ? isBigWord : isWord;
	let pos = offset;

	if (pos < text.length && match(text[pos])) {
		while (pos < text.length && match(text[pos])) pos++;
	}
	while (pos < text.length && !match(text[pos])) pos++;
	return pos;
}

function prevWordStart(text: string, offset: number, big: boolean): number {
	const match = big ? isBigWord : isWord;
	let pos = offset;

	while (pos > 0 && !match(text[pos - 1])) pos--;
	while (pos > 0 && match(text[pos - 1])) pos--;
	return pos;
}

function wordEnd(text: string, offset: number, big: boolean): number {
	if (text.length === 0) return 0;

	const match = big ? isBigWord : isWord;
	let pos = offset;
	if (pos >= text.length) pos = text.length - 1;

	if (match(text[pos]) && (pos + 1 >= text.length || !match(text[pos + 1]))) {
		pos++;
	}

	while (pos < text.length && !match(text[pos])) pos++;
	if (pos >= text.length) return text.length - 1;

	while (pos + 1 < text.length && match(text[pos + 1])) pos++;
	return pos;
}

function firstNonWhitespace(text: string, offset: number): number {
	const start = lineStart(text, offset);
	const end = lineEnd(text, offset);
	let pos = start;
	while (pos < end && /\s/.test(text[pos] ?? "")) pos++;
	return pos;
}

function isBlankLine(text: string, offset: number): boolean {
	const start = lineStart(text, offset);
	const end = lineEnd(text, offset);
	return /^\s*$/.test(text.slice(start, end));
}

function paragraphForward(text: string, offset: number): number {
	let pos = lineEnd(text, offset);
	while (pos < text.length) {
		pos += 1;
		if (pos >= text.length) return lineStart(text, text.length);
		if (!isBlankLine(text, pos) && (pos === 0 || isBlankLine(text, pos - 1))) return pos;
		pos = lineEnd(text, pos);
	}
	return offset;
}

function paragraphBackward(text: string, offset: number): number {
	let pos = lineStart(text, offset);
	while (pos > 0) {
		pos = lineStart(text, pos - 1);
		if (!isBlankLine(text, pos) && (pos === 0 || isBlankLine(text, pos - 1))) return pos;
	}
	return 0;
}

function totalLength(lines: string[]): number {
	if (lines.length === 0) return 0;
	return lines.reduce((sum, line) => sum + line.length, 0) + lines.length - 1;
}

function cursorToOffset(lines: string[], cursor: Cursor): number {
	let offset = 0;
	for (let i = 0; i < cursor.line; i++) {
		offset += (lines[i] ?? "").length + 1;
	}
	return offset + cursor.col;
}

function offsetToCursor(lines: string[], offset: number): Cursor {
	const boundedOffset = clamp(offset, 0, totalLength(lines));
	let remaining = boundedOffset;

	for (let line = 0; line < lines.length; line++) {
		const current = lines[line] ?? "";
		if (remaining <= current.length) {
			return { line, col: remaining };
		}
		remaining -= current.length;
		if (line < lines.length - 1) remaining -= 1;
	}

	const lastLine = Math.max(0, lines.length - 1);
	return { line: lastLine, col: (lines[lastLine] ?? "").length };
}

function nextGraphemeOffset(text: string, offset: number): number {
	if (offset >= text.length) return offset;
	for (const segment of graphemeSegmenter.segment(text.slice(offset))) {
		return offset + segment.segment.length;
	}
	return Math.min(offset + 1, text.length);
}

function prevGraphemeOffset(text: string, offset: number): number {
	if (offset <= 0) return 0;
	let previous = 0;
	for (const segment of graphemeSegmenter.segment(text.slice(0, offset))) {
		previous = segment.index;
	}
	return previous;
}

function replaceRange(text: string, start: number, end: number, replacement = ""): string {
	return text.slice(0, start) + replacement + text.slice(end);
}

function printableSingleGrapheme(data: string): string | undefined {
	if (!data) return undefined;
	let result: string | undefined;
	let count = 0;
	for (const segment of graphemeSegmenter.segment(data)) {
		result = segment.segment;
		count++;
		if (count > 1) return undefined;
	}
	if (!result || /[\p{Cc}\p{Cs}]/u.test(result)) return undefined;
	return result;
}

class VimModeEditor extends CustomEditor {
	private mode: Mode = "insert";
	private pending: Pending;
	private pendingTextObject?: "i" | "a";
	private pendingFindOp?: { op: "d" | "c" | "y"; motion: "f" | "F" | "t" | "T"; count: number };
	private visualAnchor?: number;
	private flashRange?: { start: number; end: number; linewise: boolean };
	private flashTimer?: ReturnType<typeof setTimeout>;
	private count = "";
	private pendingG = false;
	private lastFind: LastFind;
	private readonly redoStack: EditorSnapshot[] = [];
	private readonly replaceSessionEdits: ReplaceSessionEdit[] = [];
	private unnamedRegister = "";
	private unnamedRegisterType: "char" | "line" = "char";

	constructor(
		tui: CustomEditorArgs[0],
		theme: CustomEditorArgs[1],
		keybindings: CustomEditorArgs[2],
		private onStatusChange: (mode: Mode, pending: string) => void,
		private onYank: (text: string) => void,
		private getClipboardText: () => string | undefined,
	) {
		super(tui, theme, keybindings);
		this.emitStatus();
		setTimeout(() => this.updateCursorStyle(), 0);
	}

	private get editor(): InternalEditor {
		return this as unknown as InternalEditor;
	}

	private getPendingDisplay(): string {
		const count = this.count;
		if (this.pendingFindOp) return `${this.pendingFindOp.op}${count}${this.pendingFindOp.motion}`;
		if (this.pendingTextObject && this.pending) return `${this.pending}${count}${this.pendingTextObject}`;
		if (this.pending) return `${this.pending}${count}`;
		if (this.pendingG) return `g${count}`;
		if (count) return count;
		return "";
	}

	private matchesAction(data: string, action: string): boolean {
		return (this as unknown as { keybindings: { matches(data: string, action: string): boolean } }).keybindings.matches(data, action);
	}

	private writeCursorShape(sequence: string): void {
		try {
			process.stdout.write(sequence);
		} catch {}
		try {
			this.tui.terminal.write(sequence);
		} catch {}
	}

	private resetTerminalCursor(): void {
		(this.tui as unknown as { setShowHardwareCursor(enabled: boolean): void }).setShowHardwareCursor(false);
		this.writeCursorShape("\x1b[2 q");
	}

	private usesHardwareCursor(): boolean {
		return this.mode === "normal" || this.mode === "insert" || this.mode === "replace";
	}

	private updateCursorStyle(): void {
		const sequence = this.mode === "replace" ? "\x1b[3 q" : this.mode === "insert" ? "\x1b[5 q" : "\x1b[2 q";
		(this.tui as unknown as { setShowHardwareCursor(enabled: boolean): void }).setShowHardwareCursor(this.usesHardwareCursor());
		this.writeCursorShape(sequence);
		setTimeout(() => this.writeCursorShape(sequence), 0);
	}

	private emitStatus(): void {
		this.onStatusChange(this.mode, this.getPendingDisplay());
		this.updateCursorStyle();
		this.tui.requestRender();
	}

	private clearPending(): void {
		this.pending = undefined;
		this.pendingTextObject = undefined;
		this.pendingFindOp = undefined;
		this.pendingG = false;
		this.count = "";
		this.emitStatus();
	}

	private getVisualRange(): { start: number; end: number; linewise: boolean } | undefined {
		if (this.visualAnchor === undefined) return undefined;
		const current = this.getCurrentOffset();
		if (this.mode === "visual-line") {
			const start = Math.min(lineStart(this.getCurrentText(), this.visualAnchor), lineStart(this.getCurrentText(), current));
			const end = Math.max(lineEnd(this.getCurrentText(), this.visualAnchor), lineEnd(this.getCurrentText(), current));
			return { start, end: Math.min(end + 1, this.getCurrentText().length), linewise: true };
		}
		return {
			start: Math.min(this.visualAnchor, current),
			end: Math.max(this.visualAnchor, current) + 1,
			linewise: false,
		};
	}

	private takeCount(defaultCount = 1): number {
		const value = this.count ? Number.parseInt(this.count, 10) : defaultCount;
		this.count = "";
		return Number.isFinite(value) && value > 0 ? value : defaultCount;
	}

	private captureSnapshot(): EditorSnapshot {
		const cursor = this.getCursor();
		return {
			text: this.getText(),
			cursor: { line: cursor.line, col: cursor.col },
		};
	}

	private restoreSnapshot(snapshot: EditorSnapshot): void {
		this.editor.state.lines = snapshot.text.split("\n");
		this.editor.state.cursorLine = snapshot.cursor.line;
		this.editor.setCursorCol(snapshot.cursor.col);
		this.editor.preferredVisualCol = null;
		this.editor.historyIndex = -1;
		this.editor.lastAction = null;
		this.editor.onChange?.(snapshot.text);
		this.tui.requestRender();
	}

	private clearRedoStack(): void {
		this.redoStack.length = 0;
	}

	private flashSelection(start: number, end: number, linewise = false): void {
		if (this.flashTimer) clearTimeout(this.flashTimer);
		this.flashRange = { start: Math.min(start, end), end: Math.max(start, end), linewise };
		this.tui.requestRender();
		this.flashTimer = setTimeout(() => {
			this.flashRange = undefined;
			this.flashTimer = undefined;
			this.tui.requestRender();
		}, 120);
	}

	private writeRegister(text: string, type: "char" | "line" = "char"): void {
		this.unnamedRegister = text;
		this.unnamedRegisterType = type;
	}

	private writeYank(text: string, type: "char" | "line" = "char"): void {
		this.writeRegister(text, type);
		this.onYank(text);
	}

	private readClipboardRegister(): { text: string; type: "char" | "line" } | undefined {
		const text = this.getClipboardText();
		if (!text) return undefined;
		return {
			text,
			type: text === this.unnamedRegister ? this.unnamedRegisterType : "char",
		};
	}

	private wordObjectRange(around: boolean): { start: number; end: number } | undefined {
		const text = this.getCurrentText();
		let start = this.getCurrentOffset();
		if (!isWord(text[start])) {
			if (isWord(text[start - 1])) start -= 1;
			else return undefined;
		}
		while (start > 0 && isWord(text[start - 1])) start--;
		let end = start;
		while (end < text.length && isWord(text[end])) end++;
		if (around) {
			while (end < text.length && (text[end] === " " || text[end] === "\t")) end++;
		}
		return { start, end };
	}

	private delimitedObjectRange(char: string, around: boolean): { start: number; end: number } | undefined {
		const pairs: Record<string, [string, string]> = {
			'"': ['"', '"'],
			"'": ["'", "'"],
			"`": ["`", "`"],
			"(": ["(", ")"],
			")": ["(", ")"],
			"[": ["[", "]"],
			"]": ["[", "]"],
			"{": ["{", "}"],
			"}": ["{", "}"],
		};
		const pair = pairs[char];
		if (!pair) return undefined;
		const [open, close] = pair;
		const text = this.getCurrentText();
		if (text.length === 0) return undefined;
		let offset = Math.min(this.getCurrentOffset(), text.length - 1);

		if (open === close) {
			const startOfLine = lineStart(text, offset);
			const endOfLine = lineEnd(text, offset);
			const pairs: Array<{ start: number; end: number }> = [];
			let pendingQuote: number | undefined;
			for (let i = startOfLine; i < endOfLine; i++) {
				if (text[i] !== open || text[i - 1] === "\\") continue;
				if (pendingQuote === undefined) pendingQuote = i;
				else {
					pairs.push({ start: pendingQuote, end: i });
					pendingQuote = undefined;
				}
			}
			if (pairs.length === 0) return undefined;
			const candidates = pairs.filter((pair) => offset >= pair.start && offset <= pair.end);
			if (candidates.length > 0) {
				const pair = candidates.reduce((best, candidate) =>
					candidate.end - candidate.start < best.end - best.start ? candidate : best,
				);
				return around ? { start: pair.start, end: pair.end + 1 } : { start: pair.start + 1, end: pair.end };
			}
			let best: { start: number; end: number; distance: number } | undefined;
			for (const pair of pairs) {
				const innerStart = pair.start + 1;
				const innerEnd = pair.end;
				const distance = offset < innerStart ? innerStart - offset : offset > innerEnd ? offset - innerEnd : 0;
				if (!best || distance < best.distance || (distance === best.distance && pair.start > best.start)) {
					best = { start: pair.start, end: pair.end, distance };
				}
			}
			if (!best) return undefined;
			return around ? { start: best.start, end: best.end + 1 } : { start: best.start + 1, end: best.end };
		}

		const candidates: Array<{ start: number; end: number }> = [];
		for (let start = 0; start < text.length; start++) {
			if (text[start] !== open) continue;
			let depth = 0;
			for (let end = start + 1; end < text.length; end++) {
				if (text[end] === open) depth++;
				else if (text[end] === close) {
					if (depth === 0) {
						if (offset >= start && offset <= end) candidates.push({ start, end });
						break;
					}
					depth--;
				}
			}
		}
		if (candidates.length === 0) return undefined;
		const match = candidates.reduce((best, candidate) => {
			if (!best) return candidate;
			return candidate.end - candidate.start < best.end - best.start ? candidate : best;
		}, undefined as { start: number; end: number } | undefined);
		if (!match) return undefined;
		return around ? { start: match.start, end: match.end + 1 } : { start: match.start + 1, end: match.end };
	}

	private setMode(mode: Mode): void {
		if (this.mode === mode) return;
		this.mode = mode;
		if (mode !== "replace") this.replaceSessionEdits.length = 0;
		if (mode !== "visual" && mode !== "visual-line") this.visualAnchor = undefined;
		this.emitStatus();
		this.tui.requestRender();
	}

	private getCurrentText(): string {
		return this.getText();
	}

	private getCurrentOffset(): number {
		return cursorToOffset(this.getLines(), this.getCursor());
	}

	private setCursor(line: number, col: number): void {
		this.editor.state.cursorLine = line;
		this.editor.setCursorCol(col);
		this.tui.requestRender();
	}

	private moveToOffset(offset: number): void {
		const cursor = offsetToCursor(this.getLines(), offset);
		this.setCursor(cursor.line, cursor.col);
	}

	private enterVisual(linewise: boolean): void {
		this.clearPending();
		this.visualAnchor = this.getCurrentOffset();
		this.setMode(linewise ? "visual-line" : "visual");
	}

	private exitVisual(): void {
		const range = this.getVisualRange();
		this.setMode("normal");
		if (range) this.moveToOffset(range.start);
	}

	private applyVisual(action: "delete" | "change" | "yank" | "put"): void {
		const range = this.getVisualRange();
		if (!range) {
			this.setMode("normal");
			return;
		}
		const text = this.getCurrentText();
		const selected = text.slice(range.start, range.end);
		if (action === "yank") {
			this.writeYank(selected, range.linewise ? "line" : "char");
			this.setMode("normal");
			this.moveToOffset(range.start);
			return;
		}
		if (action === "put") {
			const register = this.readClipboardRegister();
			if (!register) {
				this.setMode("normal");
				return;
			}
			this.edit(() => ({
				text: replaceRange(text, range.start, range.end, register.text),
				cursorOffset: Math.max(range.start, range.start + register.text.length - 1),
			}));
			this.setMode("normal");
			return;
		}
		this.writeYank(selected, range.linewise ? "line" : "char");
		this.edit(() => ({
			text: replaceRange(text, range.start, range.end),
			cursorOffset: range.start,
		}));
		this.setMode(action === "change" ? "insert" : "normal");
	}

	private normalizeCursorForNormalMode(): void {
		const cursor = this.getCursor();
		const line = this.getLines()[cursor.line] ?? "";
		if (line.length === 0) {
			this.setCursor(cursor.line, 0);
			return;
		}
		if (cursor.col > 0) {
			this.setCursor(cursor.line, Math.min(cursor.col - 1, line.length - 1));
			return;
		}
		this.setCursor(cursor.line, 0);
	}

	private edit(transform: (text: string, offset: number) => { text: string; cursorOffset: number } | undefined): boolean {
		const text = this.getCurrentText();
		const offset = this.getCurrentOffset();
		const next = transform(text, offset);
		if (!next) return false;
		if (next.text === text && next.cursorOffset === offset) return false;

		this.clearRedoStack();
		this.setText(next.text);
		const cursor = offsetToCursor(this.getLines(), next.cursorOffset);
		this.setCursor(cursor.line, cursor.col);
		return true;
	}

	private enterInsert(): void {
		this.clearPending();
		this.setMode("insert");
	}

	private enterReplace(): void {
		this.clearPending();
		this.replaceSessionEdits.length = 0;
		this.setMode("replace");
	}

	private appendAfterCursor(): void {
		const text = this.getCurrentText();
		const offset = this.getCurrentOffset();
		this.moveToOffset(Math.min(offset + 1, lineEnd(text, offset)));
		this.enterInsert();
	}

	private insertLineStart(): void {
		const text = this.getCurrentText();
		const offset = this.getCurrentOffset();
		this.moveToOffset(firstNonWhitespace(text, offset));
		this.enterInsert();
	}

	private appendLineEnd(): void {
		const text = this.getCurrentText();
		const offset = this.getCurrentOffset();
		this.moveToOffset(lineEnd(text, offset));
		this.enterInsert();
	}

	private openLineBelow(): void {
		this.clearPending();
		this.edit((text, offset) => {
			const at = lineEnd(text, offset);
			return {
				text: `${text.slice(0, at)}\n${text.slice(at)}`,
				cursorOffset: at + 1,
			};
		});
		this.setMode("insert");
	}

	private openLineAbove(): void {
		this.clearPending();
		this.edit((text, offset) => {
			const at = lineStart(text, offset);
			return {
				text: `${text.slice(0, at)}\n${text.slice(at)}`,
				cursorOffset: at,
			};
		});
		this.setMode("insert");
	}

	private moveWord(direction: "next" | "prev" | "end", big: boolean, count = 1): void {
		this.moveToOffset(this.wordMotionTarget(direction, big, count));
	}

	private moveLeft(count = 1): void {
		let offset = this.getCurrentOffset();
		const text = this.getCurrentText();
		for (let i = 0; i < count; i++) {
			offset = Math.max(lineStart(text, offset), prevGraphemeOffset(text, offset));
		}
		this.moveToOffset(offset);
	}

	private moveRight(count = 1): void {
		let offset = this.getCurrentOffset();
		const text = this.getCurrentText();
		for (let i = 0; i < count; i++) {
			offset = Math.min(lineLast(text, offset), nextGraphemeOffset(text, offset));
		}
		this.moveToOffset(offset);
	}

	private moveUp(count = 1): void {
		let offset = this.getCurrentOffset();
		for (let i = 0; i < count; i++) {
			offset = moveUp(this.getCurrentText(), offset);
		}
		this.moveToOffset(offset);
	}

	private moveDown(count = 1): void {
		let offset = this.getCurrentOffset();
		for (let i = 0; i < count; i++) {
			offset = moveDown(this.getCurrentText(), offset);
		}
		this.moveToOffset(offset);
	}

	private moveLineStart(): void {
		this.moveToOffset(lineStart(this.getCurrentText(), this.getCurrentOffset()));
	}

	private moveLineFirstNonWhitespace(count = 1): void {
		if (count > 1) this.moveDown(count - 1);
		this.moveToOffset(firstNonWhitespace(this.getCurrentText(), this.getCurrentOffset()));
	}

	private moveToLine(lineNumber: number): void {
		const lines = this.getLines();
		const lineIndex = clamp(lineNumber - 1, 0, Math.max(0, lines.length - 1));
		const col = Math.min(this.getCursor().col, Math.max(0, (lines[lineIndex] ?? "").length - 1));
		this.setCursor(lineIndex, Math.max(0, col));
	}

	private moveParagraph(forward: boolean, count = 1): void {
		let offset = this.getCurrentOffset();
		for (let i = 0; i < count; i++) {
			offset = forward ? paragraphForward(this.getCurrentText(), offset) : paragraphBackward(this.getCurrentText(), offset);
		}
		this.moveToOffset(offset);
	}

	private moveLineEnd(): void {
		this.moveToOffset(lineLast(this.getCurrentText(), this.getCurrentOffset()));
	}

	private replaceUnderCursor(char: string, count = 1): void {
		this.clearPending();
		this.edit((text, offset) => {
			if (offset >= lineEnd(text, offset)) return undefined;
			let end = offset;
			let replaced = 0;
			for (let i = 0; i < count; i++) {
				end = nextGraphemeOffset(text, end);
				if (end > lineEnd(text, offset)) {
					end = lineEnd(text, offset);
					break;
				}
				replaced++;
			}
			return {
				text: replaceRange(text, offset, end, char.repeat(Math.max(1, replaced))),
				cursorOffset: offset,
			};
		});
	}

	private deleteBackwardChar(): boolean {
		const lastReplace = this.replaceSessionEdits[this.replaceSessionEdits.length - 1];
		if (this.mode === "replace" && lastReplace) {
			const restored = this.edit((text, offset) => {
				const end = lastReplace.start + lastReplace.inserted.length;
				if (offset !== end) return undefined;
				this.replaceSessionEdits.pop();
				return {
					text: replaceRange(text, lastReplace.start, end, lastReplace.original),
					cursorOffset: lastReplace.start,
				};
			});
			if (restored) return true;
		}
		return this.edit((text, offset) => {
			if (offset <= 0) return undefined;
			const start = prevGraphemeOffset(text, offset);
			return {
				text: replaceRange(text, start, offset),
				cursorOffset: start,
			};
		});
	}

	private replaceModeInput(data: string): void {
		if (data === "\r") {
			super.handleInput(data);
			return;
		}
		if (this.matchesAction(data, "tui.editor.deleteCharBackward") || matchesKey(data, "shift+backspace")) {
			this.deleteBackwardChar();
			return;
		}
		if (!(data.length === 1 && data.charCodeAt(0) >= 32)) {
			super.handleInput(data);
			return;
		}
		this.edit((text, offset) => {
			if (offset < text.length && text[offset] !== "\n") {
				const end = nextGraphemeOffset(text, offset);
				this.replaceSessionEdits.push({
					start: offset,
					inserted: data,
					original: text.slice(offset, end),
				});
				return {
					text: replaceRange(text, offset, end, data),
					cursorOffset: offset + data.length,
				};
			}
			this.replaceSessionEdits.push({ start: offset, inserted: data, original: "" });
			return {
				text: replaceRange(text, offset, offset, data),
				cursorOffset: offset + data.length,
			};
		});
	}

	private deleteToLineEnd(change: boolean): void {
		this.clearPending();
		this.edit((text, offset) => {
			const end = lineEnd(text, offset);
			if (offset > end) return undefined;
			const deleteEnd = offset === end && end < text.length ? end + 1 : end;
			if (deleteEnd <= offset) return undefined;
			this.writeYank(text.slice(offset, deleteEnd), "char");
			return {
				text: replaceRange(text, offset, deleteEnd),
				cursorOffset: offset,
			};
		});
		if (change) this.setMode("insert");
	}

	private substituteChar(): void {
		this.clearPending();
		this.edit((text, offset) => {
			if (offset >= lineEnd(text, offset)) return undefined;
			const end = nextGraphemeOffset(text, offset);
			this.writeYank(text.slice(offset, end), "char");
			return {
				text: replaceRange(text, offset, end),
				cursorOffset: offset,
			};
		});
		this.setMode("insert");
	}

	private toggleCase(count = 1): void {
		this.clearPending();
		this.edit((text, offset) => {
			if (offset >= lineEnd(text, offset)) return undefined;
			let current = offset;
			let result = text;
			for (let i = 0; i < count; i++) {
				if (current >= lineEnd(result, offset)) break;
				const end = nextGraphemeOffset(result, current);
				const segment = result.slice(current, end);
				const toggled = segment === segment.toUpperCase() ? segment.toLowerCase() : segment.toUpperCase();
				result = replaceRange(result, current, end, toggled);
				current = current + toggled.length;
			}
			return {
				text: result,
				cursorOffset: Math.max(offset, current - 1),
			};
		});
	}

	private deleteUnderCursor(count = 1): void {
		this.clearPending();
		this.edit((text, offset) => {
			if (offset >= lineEnd(text, offset)) return undefined;
			let end = offset;
			for (let i = 0; i < count; i++) {
				end = nextGraphemeOffset(text, end);
				if (end > lineEnd(text, offset)) {
					end = lineEnd(text, offset);
					break;
				}
			}
			this.writeYank(text.slice(offset, end), "char");
			return {
				text: replaceRange(text, offset, end),
				cursorOffset: offset,
			};
		});
	}

	private applyRange(start: number, end: number, change = false, yank = false): void {
		this.clearPending();
		const from = Math.min(start, end);
		const to = Math.max(start, end);
		if (to <= from) return;
		const text = this.getCurrentText();
		const selected = text.slice(from, to);
		if (yank) this.writeYank(selected, "char");
		if (yank) {
			this.flashSelection(from, to, false);
			this.moveToOffset(start <= end ? from : Math.max(from, to - 1));
			return;
		}
		this.writeYank(selected, "char");
		this.edit(() => ({
			text: replaceRange(text, from, to),
			cursorOffset: from,
		}));
		if (change) this.setMode("insert");
	}

	private wordMotionTarget(direction: "next" | "prev" | "end", big: boolean, count: number, from = this.getCurrentOffset()): number {
		let target = from;
		for (let i = 0; i < count; i++) {
			const text = this.getCurrentText();
			target =
				direction === "next"
					? nextWordStart(text, target, big)
					: direction === "prev"
						? prevWordStart(text, target, big)
						: wordEnd(text, target, big);
		}
		return target;
	}

	private deleteWord(change: boolean): void {
		const offset = this.getCurrentOffset();
		const endOffset = this.wordMotionTarget("next", false, this.takeCount(1), offset);
		this.applyRange(offset, endOffset, change);
	}

	private deleteLine(count = 1, direction: -1 | 1 | 0 = 0): void {
		this.clearPending();
		this.edit((text, offset) => {
			if (text.length === 0) return undefined;
			const { start, end } = this.lineBlockRange(count, direction);
			this.writeYank(text.slice(start, end), "line");
			const nextText = replaceRange(text, start, end);
			return {
				text: nextText,
				cursorOffset: Math.min(start, nextText.length),
			};
		});
	}

	private substituteLine(count = 1): void {
		this.deleteLine(count);
		this.setMode("insert");
	}

	private lineBlockRange(count: number, direction: -1 | 1 | 0): { start: number; end: number } {
		const text = this.getCurrentText();
		const offset = this.getCurrentOffset();
		let start = lineStart(text, offset);
		let end = lineEnd(text, offset);
		if (direction >= 0) {
			for (let i = 1; i < count; i++) {
				if (end >= text.length) break;
				end = lineEnd(text, end + 1);
			}
			end = Math.min(end + 1, text.length);
		} else {
			for (let i = 1; i < count; i++) {
				if (start === 0) break;
				start = lineStart(text, start - 1);
			}
			end = Math.min(lineEnd(text, offset) + 1, text.length);
		}
		return { start, end };
	}

	private yankLine(count = 1): void {
		this.clearPending();
		const { start, end } = this.lineBlockRange(count, 0);
		this.writeYank(this.getCurrentText().slice(start, end), "line");
		this.flashSelection(start, end, true);
	}

	private put(after: boolean, count = 1): void {
		this.clearPending();
		const register = this.readClipboardRegister();
		if (!register) return;
		const text = register.text.repeat(Math.max(1, count));
		const linewise = register.type === "line";
		this.edit((currentText, offset) => {
			if (linewise) {
				const currentLineEnd = lineEnd(currentText, offset);
				const insertAt = after ? currentLineEnd + (currentLineEnd < currentText.length ? 1 : 0) : lineStart(currentText, offset);
				const needsLeadingNewline = after && insertAt === currentText.length && currentText.length > 0 && currentText[currentText.length - 1] !== "\n";
				const insertion = needsLeadingNewline ? `\n${text}` : text;
				const nextText = replaceRange(currentText, insertAt, insertAt, insertion);
				return { text: nextText, cursorOffset: insertAt + (needsLeadingNewline ? 1 : 0) };
			}

			const insertAt = after ? Math.min(nextGraphemeOffset(currentText, offset), currentText.length) : offset;
			const nextText = replaceRange(currentText, insertAt, insertAt, text);
			return {
				text: nextText,
				cursorOffset: Math.max(insertAt, insertAt + text.length - 1),
			};
		});
	}

	private joinLines(): void {
		this.clearPending();
		this.edit((text, offset) => {
			const end = lineEnd(text, offset);
			if (end >= text.length) return undefined;

			let next = end + 1;
			while (next < text.length && (text[next] === " " || text[next] === "\t")) next++;

			const trailing = end > 0 && /[ \t]/.test(text[end - 1] ?? "");
			const paren = next < text.length && text[next] === ")";
			let nextText = replaceRange(text, end, next);
			if (!trailing && !paren) {
				nextText = replaceRange(nextText, end, end, " ");
			}

			return {
				text: nextText,
				cursorOffset: end,
			};
		});
	}

	private repeatFind(reverse = false): void {
		if (!this.lastFind) return;
		this.findChar(this.lastFind.char, reverse ? !this.lastFind.forward : this.lastFind.forward, this.lastFind.till);
	}

	private findCharTarget(char: string, forward: boolean, till = false): number | undefined {
		const text = this.getCurrentText();
		const offset = this.getCurrentOffset();
		const start = lineStart(text, offset);
		const end = lineEnd(text, offset);

		if (forward) {
			for (let i = offset + 1; i < end; i++) {
				if (text[i] === char) return till ? i - 1 : i;
			}
			return undefined;
		}

		for (let i = offset - 1; i >= start; i--) {
			if (text[i] === char) return till ? i + 1 : i;
		}
	}

	private findChar(char: string, forward: boolean, till = false): void {
		this.lastFind = { char, forward, till };
		const target = this.findCharTarget(char, forward, till);
		if (target !== undefined) this.moveToOffset(target);
	}

	private isInterruptKey(data: string): boolean {
		return this.matchesAction(data, "app.interrupt") || matchesKey(data, "escape") || matchesKey(data, "ctrl+[");
	}

	private performUndo(): void {
		const before = this.captureSnapshot();
		super.handleInput("\x1f");
		const after = this.captureSnapshot();
		if (after.text !== before.text || after.cursor.line !== before.cursor.line || after.cursor.col !== before.cursor.col) {
			this.redoStack.push(before);
		}
	}

	private performRedo(): void {
		const snapshot = this.redoStack.pop();
		if (!snapshot) return;
		this.restoreSnapshot(snapshot);
	}

	override render(width: number): string[] {
		const range = this.getVisualRange() ?? this.flashRange;
		if (!range) {
			const lines = super.render(width);
			if (!this.usesHardwareCursor()) return lines;
			return lines.map((line) =>
				line
					.replace(/(\x1b_pi:c\x07)?\x1b\[7m \x1b\[0m/g, "$1 ")
					.replace(/(\x1b_pi:c\x07)?\x1b\[7m([\s\S])\x1b\[0m/g, "$1$2"),
			);
		}

		const editor = this.editor;
		const paddingX = Math.min(editor.paddingX ?? 0, Math.max(0, Math.floor((width - 1) / 2)));
		const contentWidth = Math.max(1, width - paddingX * 2);
		const layoutWidth = Math.max(1, contentWidth - (paddingX ? 0 : 1));
		const layout = editor.layoutText?.(layoutWidth);
		if (!layout) return super.render(width);

		const terminalRows = this.tui.terminal.rows;
		const maxVisibleLines = Math.max(5, Math.floor(terminalRows * 0.3));
		const selectedBg = (s: string) => `\x1b[7m${s}\x1b[0m`;
		const horizontal = (editor.borderColor ?? ((s: string) => s))("─");
		const leftPadding = " ".repeat(paddingX);
		const rightPadding = leftPadding;
		const text = this.getCurrentText();

		let searchFrom = 0;
		const mapped = layout.map((line) => {
			const plain = line.text;
			if (plain.length === 0) {
				const start = Math.min(searchFrom, text.length);
				if (text[start] === "\n") searchFrom = start + 1;
				return { ...line, absStart: start, absEnd: start };
			}
			let start = text.indexOf(plain, searchFrom);
			if (start === -1 && searchFrom > 0) start = text.indexOf(plain);
			if (start !== -1) {
				searchFrom = start + plain.length;
				if (text[searchFrom] === "\n") searchFrom += 1;
			}
			return { ...line, absStart: start, absEnd: start === -1 ? -1 : start + plain.length };
		});

		let cursorLineIndex = mapped.findIndex((line) => line.hasCursor);
		if (cursorLineIndex === -1) cursorLineIndex = 0;
		editor.scrollOffset = editor.scrollOffset ?? 0;
		if (cursorLineIndex < editor.scrollOffset) editor.scrollOffset = cursorLineIndex;
		else if (cursorLineIndex >= editor.scrollOffset + maxVisibleLines) editor.scrollOffset = cursorLineIndex - maxVisibleLines + 1;
		const maxScrollOffset = Math.max(0, mapped.length - maxVisibleLines);
		editor.scrollOffset = Math.max(0, Math.min(editor.scrollOffset, maxScrollOffset));
		const visibleLines = mapped.slice(editor.scrollOffset, editor.scrollOffset + maxVisibleLines);

		const result: string[] = [];
		if (editor.scrollOffset > 0) {
			const indicator = `─── ↑ ${editor.scrollOffset} more `;
			result.push(truncateToWidth((editor.borderColor ?? ((s: string) => s))(indicator + "─".repeat(Math.max(0, width - visibleWidth(indicator)))), width, ""));
		} else {
			result.push(truncateToWidth(horizontal.repeat(width), width, ""));
		}

		for (const line of visibleLines) {
			let displayText = line.text;
			if (line.absStart !== -1) {
				const lineRangeEnd = range.linewise ? Math.max(line.absEnd, line.absStart + line.text.length, line.absEnd + 1) : line.absEnd;
				const overlapStart = Math.max(range.start, line.absStart);
				const overlapEnd = Math.min(range.end, lineRangeEnd);
				if (range.linewise && overlapStart <= line.absStart && overlapEnd > line.absStart) {
					displayText = selectedBg(displayText || " ");
				} else if (overlapEnd > overlapStart) {
					const localStart = overlapStart - line.absStart;
					const localEnd = overlapEnd - line.absStart;
					displayText = `${displayText.slice(0, localStart)}${selectedBg(displayText.slice(localStart, localEnd) || " ")}${displayText.slice(localEnd)}`;
				}
			}
			let lineVisibleWidth = visibleWidth(line.text);
			if (!this.flashRange && (this.mode !== "visual" && this.mode !== "visual-line") && line.hasCursor && line.cursorPos !== undefined) {
				const before = displayText.slice(0, line.cursorPos);
				const after = displayText.slice(line.cursorPos);
				if (after.length > 0) {
					const first = [...graphemeSegmenter.segment(after)][0]?.segment || "";
					displayText = before + `\x1b[7m${first}\x1b[0m` + after.slice(first.length);
				} else {
					displayText = before + "\x1b[7m \x1b[0m";
					lineVisibleWidth += 1;
				}
			}
			const padding = " ".repeat(Math.max(0, contentWidth - lineVisibleWidth));
			result.push(truncateToWidth(`${leftPadding}${displayText}${padding}${rightPadding}`, width, ""));
		}

		const linesBelow = mapped.length - (editor.scrollOffset + visibleLines.length);
		if (linesBelow > 0) {
			const indicator = `─── ↓ ${linesBelow} more `;
			result.push(truncateToWidth((editor.borderColor ?? ((s: string) => s))(indicator + "─".repeat(Math.max(0, width - visibleWidth(indicator)))), width, ""));
		} else {
			result.push(truncateToWidth(horizontal.repeat(width), width, ""));
		}
		return result;
	}

	private applyPendingOperator(target: number, inclusive = false): boolean {
		const offset = this.getCurrentOffset();
		const change = this.pending === "c";
		const yank = this.pending === "y";
		this.applyRange(offset, inclusive ? target + 1 : target, change, yank);
		return true;
	}

	private handlePendingFindOp(data: string): boolean {
		if (!this.pendingFindOp || !(data.length === 1 && data.charCodeAt(0) >= 32)) return false;
		let target: number | undefined;
		for (let i = 0; i < this.pendingFindOp.count; i++) {
			const next = this.findCharTarget(data, this.pendingFindOp.motion === "f" || this.pendingFindOp.motion === "t", this.pendingFindOp.motion === "t" || this.pendingFindOp.motion === "T");
			if (next === undefined) {
				target = undefined;
				break;
			}
			target = next;
			this.moveToOffset(next);
		}
		if (target === undefined) {
			this.clearPending();
			return true;
		}
		this.pending = this.pendingFindOp.op;
		const inclusive = this.pendingFindOp.motion === "f" || this.pendingFindOp.motion === "F";
		this.pendingFindOp = undefined;
		return this.applyPendingOperator(target, inclusive);
	}

	private handleTextObject(data: string): boolean {
		if (!this.pendingTextObject || !this.pending) {
			this.clearPending();
			return false;
		}
		const around = this.pendingTextObject === "a";
		const normalized = data === ")" ? "(" : data === "]" ? "[" : data === "}" ? "{" : data;
		const range = normalized === "w" ? this.wordObjectRange(around) : this.delimitedObjectRange(normalized, around);
		if (!range) {
			this.clearPending();
			return true;
		}
		const change = this.pending === "c";
		const yank = this.pending === "y";
		this.applyRange(range.start, range.end, change, yank);
		return true;
	}

	private handlePending(data: string): boolean {
		if (this.isInterruptKey(data)) {
			this.clearPending();
			this.tui.requestRender();
			return true;
		}

		switch (this.pending) {
			case "r": {
				const char = printableSingleGrapheme(data);
				if (char) {
					this.replaceUnderCursor(char, this.takeCount(1));
					return true;
				}
				break;
			}
			case "y":
			case "d":
			case "c": {
				if (data === "i" || data === "a") {
					this.pendingTextObject = data;
					this.emitStatus();
					return true;
				}
				if (data === "f" || data === "F" || data === "t" || data === "T") {
					this.pendingFindOp = { op: this.pending, motion: data, count: this.takeCount(1) };
					this.emitStatus();
					return true;
				}
				if (data === this.pending) {
					const count = this.takeCount(1);
					if (this.pending === "y") this.yankLine(count);
					else if (this.pending === "d") this.deleteLine(count);
					else this.substituteLine(count);
					return true;
				}
				if (data === "w") return this.applyPendingOperator(this.wordMotionTarget("next", false, this.takeCount(1)));
				if (data === "e") return this.applyPendingOperator(this.wordMotionTarget("end", false, this.takeCount(1)), true);
				if (data === "b") return this.applyPendingOperator(this.wordMotionTarget("prev", false, this.takeCount(1)));
				if (data === "W") return this.applyPendingOperator(this.wordMotionTarget("next", true, this.takeCount(1)));
				if (data === "E") return this.applyPendingOperator(this.wordMotionTarget("end", true, this.takeCount(1)), true);
				if (data === "B") return this.applyPendingOperator(this.wordMotionTarget("prev", true, this.takeCount(1)));
				if (data === "$") return this.applyPendingOperator(lineEnd(this.getCurrentText(), this.getCurrentOffset()));
				if (data === "0") return this.applyPendingOperator(lineStart(this.getCurrentText(), this.getCurrentOffset()));
				if (data === "^") return this.applyPendingOperator(firstNonWhitespace(this.getCurrentText(), this.getCurrentOffset()));
				if (data === "_") {
					const count = this.takeCount(1);
					if (this.pending === "y") this.yankLine(count);
					else if (this.pending === "d") this.deleteLine(count);
					else this.substituteLine(count);
					return true;
				}
				if (data === "G") {
					const offset = this.getCurrentOffset();
					const start = lineStart(this.getCurrentText(), offset);
					const end = this.getCurrentText().length;
					const pending = this.pending;
					this.clearPending();
					const selected = this.getCurrentText().slice(start, end);
					this.writeYank(selected, "line");
					if (pending === "y") return true;
					this.edit(() => ({ text: replaceRange(this.getCurrentText(), start, end), cursorOffset: start }));
					if (pending === "c") this.setMode("insert");
					return true;
				}
				if (data === "j") {
					const count = this.takeCount(1);
					if (this.pending === "y") this.yankLine(count + 1);
					else if (this.pending === "d") this.deleteLine(count + 1, 1);
					else this.substituteLine(count + 1);
					return true;
				}
				if (data === "k") {
					const count = this.takeCount(1);
					if (this.pending === "y") {
						const { start, end } = this.lineBlockRange(count + 1, -1);
						this.writeYank(this.getCurrentText().slice(start, end), "line");
						this.clearPending();
					} else if (this.pending === "d") this.deleteLine(count + 1, -1);
					else this.deleteLine(count + 1, -1), this.setMode("insert");
					return true;
				}
				break;
			}
			case "f":
			case "F":
			case "t":
			case "T": {
				if (data.length === 1 && data.charCodeAt(0) >= 32) {
					const forward = this.pending === "f" || this.pending === "t";
					const till = this.pending === "t" || this.pending === "T";
					if (this.pendingTextObject) {
						this.clearPending();
						return true;
					}
					if (this.pending === "f" || this.pending === "F" || this.pending === "t" || this.pending === "T") {
						this.findChar(data, forward, till);
						this.clearPending();
						return true;
					}
				}
				break;
			}
			default:
				return false;
		}

		const printable = data.length === 1 && data.charCodeAt(0) >= 32;
		this.clearPending();
		return printable;
	}

	handleInput(data: string): void {
		if (this.matchesAction(data, "app.editor.external")) {
			this.resetTerminalCursor();
			super.handleInput(data);
			setTimeout(() => this.updateCursorStyle(), 0);
			return;
		}

		if (this.isInterruptKey(data)) {
			if (this.mode === "visual" || this.mode === "visual-line") {
				this.exitVisual();
			} else if (this.mode === "insert" || this.mode === "replace") {
				if (this.isShowingAutocomplete()) {
					super.handleInput(data);
				}
				this.clearPending();
				this.normalizeCursorForNormalMode();
				this.setMode("normal");
			} else if (this.pending || this.pendingTextObject || this.pendingFindOp || this.pendingG || this.count) {
				this.clearPending();
				this.tui.requestRender();
			} else {
				super.handleInput(data);
			}
			return;
		}

		if (this.mode === "insert" || this.mode === "replace") {
			if (this.mode === "insert" && (matchesKey(data, Key.shiftAlt("a")) || data === "\x1bA")) {
				this.moveToOffset(lineEnd(this.getCurrentText(), this.getCurrentOffset()));
				return;
			}
			if (this.mode === "insert" && (matchesKey(data, Key.shiftAlt("i")) || data === "\x1bI")) {
				this.moveToOffset(lineStart(this.getCurrentText(), this.getCurrentOffset()));
				return;
			}
			if (this.mode === "insert" && (matchesKey(data, Key.alt("o")) || data === "\x1bo")) {
				this.openLineBelow();
				return;
			}
			if (this.mode === "insert" && (matchesKey(data, Key.shiftAlt("o")) || data === "\x1bO")) {
				this.openLineAbove();
				return;
			}
			if (this.mode === "replace") {
				this.replaceModeInput(data);
				return;
			}
			super.handleInput(data);
			return;
		}

		if (this.mode === "visual" || this.mode === "visual-line") {
			if (this.matchesAction(data, "tui.input.copy")) {
				this.applyVisual("yank");
				return;
			}
			switch (data) {
				case "v":
					if (this.mode === "visual") this.exitVisual();
					else this.enterVisual(false);
					return;
				case "V":
					if (this.mode === "visual-line") this.exitVisual();
					else this.enterVisual(true);
					return;
				case "d":
				case "x":
					this.applyVisual("delete");
					return;
				case "c":
					this.applyVisual("change");
					return;
				case "y":
					this.applyVisual("yank");
					return;
				case "p":
				case "P":
					this.applyVisual("put");
					return;
			}
		}

		if (this.pending && data >= "0" && data <= "9") {
			if (this.count.length < 5) this.count += data;
			if (this.count.length >= 5) {
				this.clearPending();
				return;
			}
			this.emitStatus();
			return;
		}

		if ((this.pending === "d" || this.pending === "c" || this.pending === "y") && (data === "i" || data === "a")) {
			this.pendingTextObject = data;
			this.emitStatus();
			return;
		}
		if (this.pendingTextObject && (data === '"' || data === "'" || data === "`" || data === "(" || data === ")" || data === "[" || data === "]" || data === "{" || data === "}" || data === "w")) {
			this.handleTextObject(data);
			return;
		}


		if (this.pendingFindOp) {
			if (this.handlePendingFindOp(data)) return;
		}

		if (this.pendingTextObject) {
			if (this.handleTextObject(data)) return;
		}

		if (this.pending && this.handlePending(data)) {
			return;
		}

		if (this.pendingG) {
			if (data === "g") {
				const count = this.takeCount(1);
				this.pendingG = false;
				this.emitStatus();
				this.moveToLine(count);
				return;
			}
			this.pendingG = false;
			this.emitStatus();
		}

		if (data >= "0" && data <= "9" && (data !== "0" || this.count.length > 0)) {
			if (this.count.length < 5) this.count += data;
			if (this.count.length >= 5) {
				this.clearPending();
				return;
			}
			this.emitStatus();
			return;
		}

		switch (data) {
			case "v":
				this.enterVisual(false);
				return;
			case "V":
				this.enterVisual(true);
				return;
			case "u":
			case "\x1f": {
				const count = this.takeCount(1);
				for (let i = 0; i < count; i++) this.performUndo();
				return;
			}
			case "\x12": {
				const count = this.takeCount(1);
				for (let i = 0; i < count; i++) this.performRedo();
				return;
			}
			case "I":
				this.insertLineStart();
				return;
			case "A":
				this.appendLineEnd();
				return;
			case "h":
				this.moveLeft(this.takeCount(1));
				return;
			case "j":
				this.moveDown(this.takeCount(1));
				return;
			case "k":
				this.moveUp(this.takeCount(1));
				return;
			case "l":
				this.moveRight(this.takeCount(1));
				return;
			case "w":
				this.moveWord("next", false, this.takeCount(1));
				return;
			case "b":
				this.moveWord("prev", false, this.takeCount(1));
				return;
			case "e":
				this.moveWord("end", false, this.takeCount(1));
				return;
			case "W":
				this.moveWord("next", true, this.takeCount(1));
				return;
			case "B":
				this.moveWord("prev", true, this.takeCount(1));
				return;
			case "E":
				this.moveWord("end", true, this.takeCount(1));
				return;
			case "0":
				this.moveLineStart();
				this.count = "";
				return;
			case "^":
				this.moveLineFirstNonWhitespace();
				this.count = "";
				return;
			case "_":
				this.moveLineFirstNonWhitespace(this.takeCount(1));
				return;
			case "$":
				this.moveLineEnd();
				this.count = "";
				return;
			case "g":
				this.pendingG = true;
				this.emitStatus();
				return;
			case "G":
				this.moveToLine(this.takeCount(this.getLines().length));
				return;
			case "{":
				this.moveParagraph(false, this.takeCount(1));
				return;
			case "}":
				this.moveParagraph(true, this.takeCount(1));
				return;
			case "o":
				this.openLineBelow();
				return;
			case "O":
				this.openLineAbove();
				return;
			case "x":
				this.deleteUnderCursor(this.takeCount(1));
				return;
			case "~":
				this.toggleCase(this.takeCount(1));
				return;
			case "s":
				this.substituteChar();
				return;
			case "D":
				this.deleteToLineEnd(false);
				return;
			case "C":
				this.deleteToLineEnd(true);
				return;
			case "r":
				this.pending = "r";
				this.emitStatus();
				return;
			case "R":
				this.enterReplace();
				return;
			case "p":
				this.put(true, this.takeCount(1));
				return;
			case "P":
				this.put(false, this.takeCount(1));
				return;
			case "Y":
				this.yankLine(this.takeCount(1));
				return;
			case ";":
				this.repeatFind(false);
				return;
			case ",":
				this.repeatFind(true);
				return;
			case "J":
				this.joinLines();
				return;
			case "S":
				this.substituteLine(this.takeCount(1));
				return;
			case "d":
				this.pending = "d";
				this.emitStatus();
				return;
			case "c":
				this.pending = "c";
				this.emitStatus();
				return;
			case "y":
				this.pending = "y";
				this.emitStatus();
				return;
			case "i":
				if (this.pending === "d" || this.pending === "c" || this.pending === "y") {
					this.pendingTextObject = "i";
					return;
				}
				this.enterInsert();
				return;
			case "a":
				if (this.pending === "d" || this.pending === "c" || this.pending === "y") {
					this.pendingTextObject = "a";
					return;
				}
				this.appendAfterCursor();
				return;
			case "f":
				this.pending = "f";
				this.emitStatus();
				return;
			case "F":
				this.pending = "F";
				this.emitStatus();
				return;
			case "t":
				this.pending = "t";
				this.emitStatus();
				return;
			case "T":
				this.pending = "T";
				this.emitStatus();
				return;
		}

		if (data.length === 1 && data.charCodeAt(0) >= 32) return;
		if (this.count || this.pendingG || this.pendingTextObject || this.pendingFindOp || this.pending) this.clearPending();
		super.handleInput(data);
	}
}

export default function (pi: ExtensionAPI) {
	let mode: Mode = "insert";
	let pendingStatus = "";
	let enabled = true;

	const applyVimMode = (ctx: ExtensionContext): void => {
		mode = "insert";
		pendingStatus = "";

		if (!enabled) {
			ctx.ui.setFooter(undefined);
			ctx.ui.setEditorComponent(undefined);
			return;
		}

		ctx.ui.setFooter((tui, theme, footerData) => {
			const unsubscribe = footerData.onBranchChange(() => tui.requestRender());

			return {
				dispose: unsubscribe,
				invalidate() {},
				render(width: number): string[] {
					let totalInput = 0;
					let totalOutput = 0;
					let totalCacheRead = 0;
					let totalCacheWrite = 0;
					let totalCost = 0;

					for (const entry of ctx.sessionManager.getEntries()) {
						if (entry.type === "message" && entry.message.role === "assistant") {
							totalInput += entry.message.usage.input;
							totalOutput += entry.message.usage.output;
							totalCacheRead += entry.message.usage.cacheRead;
							totalCacheWrite += entry.message.usage.cacheWrite;
							totalCost += entry.message.usage.cost.total;
						}
					}

					const contextUsage = ctx.getContextUsage();
					const contextWindow = contextUsage?.contextWindow ?? ctx.model?.contextWindow ?? 0;
					const contextPercentValue = contextUsage?.percent ?? 0;
					const contextPercent = contextUsage?.percent !== null ? contextPercentValue.toFixed(1) : "?";

					let pwd = ctx.sessionManager.getCwd();
					const home = process.env.HOME || process.env.USERPROFILE;
					if (home && pwd.startsWith(home)) {
						pwd = `~${pwd.slice(home.length)}`;
					}

					const branch = footerData.getGitBranch();
					if (branch) pwd = `${pwd} (${branch})`;

					const sessionName = ctx.sessionManager.getSessionName();
					if (sessionName) pwd = `${pwd} • ${sessionName}`;

					const prefix =
						mode === "insert"
							? theme.fg("muted", "-- INSERT -- ")
							: mode === "replace"
								? theme.fg("muted", "-- REPLACE -- ")
								: mode === "visual"
									? theme.fg("accent", "-- VISUAL -- ")
									: mode === "visual-line"
										? theme.fg("accent", "-- VISUAL LINE -- ")
										: "";
					const pwdLine = truncateToWidth(prefix + theme.fg("dim", pwd), width, theme.fg("dim", "..."));

					const statsParts: string[] = [];
					if (totalInput) statsParts.push(`↑${formatTokens(totalInput)}`);
					if (totalOutput) statsParts.push(`↓${formatTokens(totalOutput)}`);
					if (totalCacheRead) statsParts.push(`R${formatTokens(totalCacheRead)}`);
					if (totalCacheWrite) statsParts.push(`W${formatTokens(totalCacheWrite)}`);

					const usingSubscription = ctx.model ? ctx.modelRegistry.isUsingOAuth(ctx.model) : false;
					if (totalCost || usingSubscription) {
						statsParts.push(`$${totalCost.toFixed(3)}${usingSubscription ? " (sub)" : ""}`);
					}

					const contextPercentDisplay =
						contextPercent === "?" ? `?/${formatTokens(contextWindow)}` : `${contextPercent}%/${formatTokens(contextWindow)}`;
					const contextPart =
						contextPercentValue > 90
							? theme.fg("error", contextPercentDisplay)
							: contextPercentValue > 70
								? theme.fg("warning", contextPercentDisplay)
								: contextPercentDisplay;
					statsParts.push(contextPart);

					let statsLeft = statsParts.join(" ");
					let statsLeftWidth = visibleWidth(statsLeft);
					if (statsLeftWidth > width) {
						statsLeft = truncateToWidth(statsLeft, width, "...");
						statsLeftWidth = visibleWidth(statsLeft);
					}

					const modelName = ctx.model?.id || "no-model";
					const thinkingLevel = pi.getThinkingLevel();
					let modelRightSide =
						ctx.model?.reasoning && thinkingLevel !== "off"
							? `${modelName} • ${thinkingLevel}`
							: ctx.model?.reasoning
								? `${modelName} • thinking off`
								: modelName;

					if (footerData.getAvailableProviderCount() > 1 && ctx.model) {
						const withProvider = `(${ctx.model.provider}) ${modelRightSide}`;
						if (statsLeftWidth + 2 + visibleWidth(withProvider) <= width) {
							modelRightSide = withProvider;
						}
					}
					const pendingPrefix = pendingStatus ? `${pendingStatus}..` : "";
					const modelWidth = visibleWidth(modelRightSide);
					const minGap = statsLeftWidth > 0 ? 2 : 0;
					const modelStart = Math.max(statsLeftWidth + minGap, width - modelWidth);
					const beforeModelWidth = Math.max(0, modelStart - statsLeftWidth);
					let beforeModel = " ".repeat(beforeModelWidth);
					if (pendingPrefix) {
						const pendingWithSpace = `${pendingPrefix} `;
						const pendingWidth = visibleWidth(pendingWithSpace);
						if (pendingWidth <= beforeModelWidth) {
							beforeModel = `${" ".repeat(beforeModelWidth - pendingWidth)}${pendingWithSpace}`;
						}
					}
					const statsLine = truncateToWidth(`${statsLeft}${beforeModel}${modelRightSide}`, width, "");

					const dimStatsLeft = theme.fg("dim", statsLeft);
					const middle = statsLine.slice(statsLeft.length, statsLeft.length + beforeModel.length);
					const right = statsLine.slice(statsLeft.length + beforeModel.length);
					const coloredMiddle = pendingPrefix && middle.includes(`${pendingPrefix} `)
						? theme.fg("dim", middle.slice(0, middle.indexOf(`${pendingPrefix} `))) + theme.fg("muted", `${pendingPrefix} `)
						: theme.fg("dim", middle);
					const lines = [pwdLine, dimStatsLeft + coloredMiddle + theme.fg("dim", right)];

					const extensionStatuses = footerData.getExtensionStatuses();
					if (extensionStatuses.size > 0) {
						const statusLine = Array.from(extensionStatuses.entries())
							.sort(([a], [b]) => a.localeCompare(b))
							.map(([, text]) => sanitizeStatusText(text))
							.join(" ");
						lines.push(truncateToWidth(statusLine, width, theme.fg("dim", "...")));
					}

					return lines;
				},
			};
		});

		ctx.ui.setEditorComponent(
			(tui, theme, keybindings) =>
				new VimModeEditor(
					tui,
					theme,
					keybindings,
					(nextMode, nextPending) => {
						mode = nextMode;
						pendingStatus = nextPending;
					},
					(text) => {
						void copyToClipboard(text).catch(() => {});
					},
					() => readSystemClipboardText(),
				),
		);
	};

	pi.registerCommand("vim-mode", {
		description: "Toggle vim mode",
		handler: async (_args, ctx) => {
			enabled = !enabled;
			applyVimMode(ctx);
			ctx.ui.notify(`Vim mode ${enabled ? "enabled" : "disabled"}.`, "info");
		},
	});

	pi.on("session_start", (_event, ctx) => {
		applyVimMode(ctx);
	});
}