/**
 * Shared utilities and constants for tool renderers.
 *
 * Provides consistent formatting, truncation, and display patterns across all
 * tool renderers to ensure a unified TUI experience.
 */

import * as os from "node:os";
import * as path from "node:path";
import type { ToolCallContext } from "@oh-my-pi/pi-agent-core";
import type { Ellipsis } from "@oh-my-pi/pi-natives";
import type { Component } from "@oh-my-pi/pi-tui";
import { replaceTabs, truncateToWidth } from "@oh-my-pi/pi-tui";
import { pluralize } from "@oh-my-pi/pi-utils";
import { settings } from "../config/settings";
import type { Theme } from "../modes/theme/theme";
import { Hasher } from "../tui/utils";
import { formatDimensionNote, type ResizedImage } from "../utils/image-resize";

export { Ellipsis } from "@oh-my-pi/pi-natives";
export { replaceTabs, truncateToWidth, wrapTextWithAnsi } from "@oh-my-pi/pi-tui";

// =============================================================================
// Standardized Display Constants
// =============================================================================

/** Resolve inline image dimension caps from settings and viewport. */
export function resolveImageOptions(): { maxWidthCells: number; maxHeightCells?: number } {
	const maxWidthCells = settings.get("tui.maxInlineImageColumns");
	const rowSetting = Math.max(0, settings.get("tui.maxInlineImageRows"));
	const viewportRows = process.stdout.rows;
	const viewportFraction = viewportRows ? Math.floor(viewportRows * 0.6) : 0;
	let maxHeightCells: number | undefined;
	if (rowSetting === 0) {
		// No explicit cap — use viewport fraction as safety bound
		maxHeightCells = viewportFraction || undefined;
	} else if (viewportFraction > 0) {
		maxHeightCells = Math.min(rowSetting, viewportFraction);
	} else {
		// Viewport size unknown (transitional state) — honor explicit setting
		maxHeightCells = rowSetting;
	}
	return { maxWidthCells, maxHeightCells };
}

/** Preview limits for collapsed/expanded views */
export const PREVIEW_LIMITS = {
	/** Lines shown in collapsed view */
	COLLAPSED_LINES: 3,
	/** Lines shown in expanded view */
	EXPANDED_LINES: 12,
	/** Items (files, results) shown in collapsed view */
	COLLAPSED_ITEMS: 8,
	/** Output preview lines in collapsed view */
	OUTPUT_COLLAPSED: 3,
	/** Output preview lines in expanded view */
	OUTPUT_EXPANDED: 10,
	/** Max hunks shown when collapsed (edit tool) */
	DIFF_COLLAPSED_HUNKS: 8,
	/** Max diff lines shown when collapsed (edit tool) */
	DIFF_COLLAPSED_LINES: 40,
} as const;

/** Truncation lengths for different content types */
export const TRUNCATE_LENGTHS = {
	/** Short titles, labels */
	TITLE: 60,
	/** Medium-length content (messages, previews) */
	CONTENT: 80,
	/** Longer content (code, explanations) */
	LONG: 100,
	/** Full line content */
	LINE: 110,
	/** Very short (task previews, badges) */
	SHORT: 40,
} as const;

/** Standard expand hint text */
export const EXPAND_HINT = "(Ctrl+O for more)";

// =============================================================================
// Text Truncation Utilities
// =============================================================================

/**
 * Get first N lines of text as preview, with each line truncated.
 */
export function getPreviewLines(text: string, maxLines: number, maxLineLen: number, ellipsis?: Ellipsis): string[] {
	const lines = text.split("\n").filter(l => l.trim());
	return lines.slice(0, maxLines).map(l => truncateToWidth(l.trim(), maxLineLen, ellipsis));
}

// =============================================================================
// URL Utilities
// =============================================================================

/**
 * Extract domain from URL, stripping www. prefix.
 */
export function getDomain(url: string): string {
	try {
		const u = new URL(url);
		return u.hostname.replace(/^www\./, "");
	} catch {
		return url;
	}
}

// =============================================================================
// Formatting Utilities
// =============================================================================

export { formatAge, formatBytes, formatCount, formatDuration, pluralize } from "@oh-my-pi/pi-utils";

// =============================================================================
// Theme Helper Utilities
// =============================================================================

/**
 * Get the appropriate status icon with color for a given state.
 * Standardizes status icon usage across all renderers.
 */
export function formatStatusIcon(status: ToolUIStatus, theme: Theme, spinnerFrame?: number): string {
	switch (status) {
		case "success":
			return theme.styledSymbol("status.success", "success");
		case "error":
			return theme.styledSymbol("status.error", "error");
		case "warning":
			return theme.styledSymbol("status.warning", "warning");
		case "info":
			return theme.styledSymbol("status.info", "accent");
		case "pending":
			return theme.styledSymbol("status.pending", "muted");
		case "running":
			if (spinnerFrame !== undefined) {
				const frames = theme.spinnerFrames;
				return frames[spinnerFrame % frames.length];
			}
			return theme.styledSymbol("status.running", "accent");
		case "aborted":
			return theme.styledSymbol("status.aborted", "error");
	}
}

/**
 * Format the expand hint with proper theming.
 * Returns empty string if already expanded or there is nothing more to show.
 */
export function formatExpandHint(theme: Theme, expanded?: boolean, hasMore?: boolean): string {
	if (expanded) return "";
	if (hasMore === false) return "";
	return theme.fg("dim", wrapBrackets(EXPAND_HINT, theme));
}

/**
 * Format a badge like [done] or [failed] with brackets and color.
 */
export function formatBadge(label: string, color: ToolUIColor, theme: Theme): string {
	const left = theme.format.bracketLeft;
	const right = theme.format.bracketRight;
	return theme.fg(color, `${left}${label}${right}`);
}

/**
 * Build a "more items" suffix line for truncated lists.
 * Uses consistent wording pattern.
 */
export function formatMoreItems(remaining: number, itemType: string): string {
	const safeRemaining = Number.isFinite(remaining) ? remaining : 0;
	return `… ${safeRemaining} more ${pluralize(itemType, safeRemaining)}`;
}

export function formatMeta(meta: string[], theme: Theme): string {
	return meta.length > 0 ? ` ${theme.fg("muted", meta.join(theme.sep.dot))}` : "";
}

export function formatErrorMessage(message: string | undefined, theme: Theme): string {
	const clean = (message ?? "").replace(/^Error:\s*/, "").trim();
	return `${theme.styledSymbol("status.error", "error")} ${theme.fg("error", `Error: ${clean || "Unknown error"}`)}`;
}

export function formatEmptyMessage(message: string, theme: Theme): string {
	return `${theme.styledSymbol("status.warning", "warning")} ${theme.fg("muted", message)}`;
}

// =============================================================================
// Code Frame Formatting
// =============================================================================

export type CodeFrameMarker = "" | " " | "*" | "+" | "-" | ">";

export function formatCodeFrameLine(
	marker: CodeFrameMarker,
	lineNumber: string | number,
	content: string,
	lineNumberWidth: number,
): string {
	const markerText = marker.trim();
	const lineNumberText = String(lineNumber).trim();
	const gutterText = markerText && lineNumberText ? `${markerText}${lineNumberText}` : lineNumberText || markerText;
	return `${gutterText.padStart(lineNumberWidth + 1, " ")}│${content}`;
}

// =============================================================================
// Tool UI Helpers
// =============================================================================

export type ToolUIStatus = "success" | "error" | "warning" | "info" | "pending" | "running" | "aborted";
export type ToolUIColor = "success" | "error" | "warning" | "accent" | "muted";

export interface ToolUITitleOptions {
	bold?: boolean;
}

export function formatTitle(label: string, theme: Theme, options?: ToolUITitleOptions): string {
	const content = options?.bold === false ? label : theme.bold(label);
	return theme.fg("toolTitle", content);
}

// =============================================================================
// Diagnostic Formatting
// =============================================================================

interface ParsedDiagnostic {
	filePath: string;
	line: number;
	col: number;
	severity: "error" | "warning" | "info" | "hint";
	source?: string;
	message: string;
	code?: string;
}

function sanitizeDiagnosticDisplayText(text: string): string {
	return replaceTabs(text);
}

function getSeverityRank(severity: ParsedDiagnostic["severity"]): number {
	switch (severity) {
		case "error":
			return 0;
		case "warning":
			return 1;
		case "info":
			return 2;
		case "hint":
			return 3;
	}
}

function parseDiagnosticMessage(msg: string): ParsedDiagnostic | null {
	const match = msg.match(/^(.+?):(\d+):(\d+)\s+\[(\w+)\]\s+(?:\[([^\]]+)\]\s+)?(.+?)(?:\s+\(([^)]+)\))?$/);
	if (!match) return null;
	return {
		filePath: sanitizeDiagnosticDisplayText(match[1]),
		line: parseInt(match[2], 10),
		col: parseInt(match[3], 10),
		severity: match[4] as ParsedDiagnostic["severity"],
		source: match[5] ? sanitizeDiagnosticDisplayText(match[5]) : undefined,
		message: sanitizeDiagnosticDisplayText(match[6]),
		code: match[7] ? sanitizeDiagnosticDisplayText(match[7]) : undefined,
	};
}

export function formatDiagnostics(
	diag: { errored: boolean; summary: string; messages: string[] },
	expanded: boolean,
	theme: Theme,
	getLangIcon: (filePath: string) => string,
): string {
	if (diag.messages.length === 0) return "";

	const byFile = new Map<string, ParsedDiagnostic[]>();
	const unparsed: string[] = [];

	for (const msg of diag.messages) {
		const parsed = parseDiagnosticMessage(msg);
		if (parsed) {
			const existing = byFile.get(parsed.filePath) ?? [];
			existing.push(parsed);
			byFile.set(parsed.filePath, existing);
		} else {
			unparsed.push(sanitizeDiagnosticDisplayText(msg));
		}
	}

	for (const diagnostics of byFile.values()) {
		diagnostics.sort((a, b) => {
			const severityCompare = getSeverityRank(a.severity) - getSeverityRank(b.severity);
			if (severityCompare !== 0) return severityCompare;
			if (a.line !== b.line) return a.line - b.line;
			if (a.col !== b.col) return a.col - b.col;
			return a.message.localeCompare(b.message);
		});
	}

	const headerIcon = diag.errored
		? theme.styledSymbol("status.error", "error")
		: theme.styledSymbol("status.warning", "warning");
	const summary = sanitizeDiagnosticDisplayText(diag.summary);
	let output = `\n\n${headerIcon} ${theme.fg("toolTitle", "Diagnostics")} ${theme.fg("dim", `(${summary})`)}`;

	const maxDiags = expanded ? diag.messages.length : 5;
	let diagsShown = 0;

	const files = Array.from(byFile.entries());

	// Count total diagnostics for "... X more" calculation
	const totalParsedDiags = files.reduce((sum, [, diags]) => sum + diags.length, 0);
	const totalDiags = totalParsedDiags + unparsed.length;

	// Helper to check if this is the very last item in the tree
	const isTreeEnd = (fileIdx: number, diagIdx: number | null, unparsedIdx: number | null): boolean => {
		const willShowMore = totalDiags > diagsShown + 1;
		if (willShowMore) return false;

		if (unparsedIdx !== null) {
			return unparsedIdx === unparsed.length - 1;
		}
		if (diagIdx !== null) {
			const isLastDiagInFile = diagIdx === files[fileIdx][1].length - 1;
			const isLastFile = fileIdx === files.length - 1;
			return isLastDiagInFile && isLastFile && unparsed.length === 0;
		}
		// File node - never the tree end if it has diagnostics
		return false;
	};

	for (let fi = 0; fi < files.length && diagsShown < maxDiags; fi++) {
		const [filePath, diagnostics] = files[fi];
		// File is "last" only if no more files AND no unparsed AND we'll show all diags AND no "... X more"
		const remainingDiagsInFile = diagnostics.length;
		const remainingDiagsAfter = files.slice(fi + 1).reduce((sum, [, d]) => sum + d.length, 0) + unparsed.length;
		const willShowAllRemaining = diagsShown + remainingDiagsInFile + remainingDiagsAfter <= maxDiags;
		const isLastFileNode = fi === files.length - 1 && unparsed.length === 0 && willShowAllRemaining;
		const fileBranch = isLastFileNode ? theme.tree.last : theme.tree.branch;

		const fileIcon = theme.fg("muted", getLangIcon(filePath));
		output += `\n ${theme.fg("dim", fileBranch)} ${fileIcon} ${theme.fg("accent", filePath)}`;

		for (let di = 0; di < diagnostics.length && diagsShown < maxDiags; di++) {
			const d = diagnostics[di];
			const isLastDiagInFile = di === diagnostics.length - 1;
			// This is the last visible diag in file if it's actually last OR we're about to hit the limit
			const atDisplayLimit = diagsShown + 1 >= maxDiags;
			const isLastVisibleInFile = isLastDiagInFile || atDisplayLimit;
			// Check if this is the last visible item in the entire tree
			const isVeryLast = isTreeEnd(fi, di, null);
			const diagBranch = isLastFileNode
				? isLastVisibleInFile || isVeryLast
					? `  ${theme.tree.last}`
					: `  ${theme.tree.branch}`
				: isLastVisibleInFile || isVeryLast
					? `${theme.tree.vertical} ${theme.tree.last}`
					: `${theme.tree.vertical} ${theme.tree.branch}`;

			const sevIcon =
				d.severity === "error"
					? theme.styledSymbol("status.error", "error")
					: d.severity === "warning"
						? theme.styledSymbol("status.warning", "warning")
						: theme.styledSymbol("status.info", "muted");
			const location = theme.fg("dim", `:${d.line}:${d.col}`);
			const codeTag = d.code ? theme.fg("dim", ` (${d.code})`) : "";
			const msgColor = d.severity === "error" ? "error" : d.severity === "warning" ? "warning" : "toolOutput";

			output += `\n ${theme.fg("dim", diagBranch)} ${sevIcon}${location} ${theme.fg(msgColor, d.message)}${codeTag}`;
			diagsShown++;
		}
	}

	for (let ui = 0; ui < unparsed.length && diagsShown < maxDiags; ui++) {
		const msg = unparsed[ui];
		const isVeryLast = isTreeEnd(-1, null, ui);
		const branch = isVeryLast ? theme.tree.last : theme.tree.branch;
		const color = msg.includes("[error]") ? "error" : msg.includes("[warning]") ? "warning" : "dim";
		output += `\n ${theme.fg("dim", branch)} ${theme.fg(color, msg)}`;
		diagsShown++;
	}

	if (totalDiags > diagsShown) {
		const remaining = totalDiags - diagsShown;
		output += `\n ${theme.fg("dim", theme.tree.last)} ${theme.fg(
			"muted",
			`… ${remaining} more`,
		)} ${formatExpandHint(theme)}`;
	}

	return output;
}

// =============================================================================
// Diff Utilities
// =============================================================================

export interface DiffStats {
	added: number;
	removed: number;
	hunks: number;
	lines: number;
}

export function getDiffStats(diffText: string): DiffStats {
	const lines = diffText ? diffText.split("\n") : [];
	let added = 0;
	let removed = 0;
	let hunks = 0;
	let inHunk = false;

	for (const line of lines) {
		const isAdded = line.startsWith("+");
		const isRemoved = line.startsWith("-");
		const isChange = isAdded || isRemoved;

		if (isAdded) added++;
		if (isRemoved) removed++;

		if (isChange && !inHunk) {
			hunks++;
			inHunk = true;
		} else if (!isChange) {
			inHunk = false;
		}
	}

	return { added, removed, hunks, lines: lines.length };
}

export function formatDiffStats(added: number, removed: number, hunks: number, theme: Theme): string {
	const parts: string[] = [];
	if (added > 0) parts.push(theme.fg("toolDiffAdded", `+${added}`));
	if (removed > 0) parts.push(theme.fg("toolDiffRemoved", `-${removed}`));
	if (hunks > 0) parts.push(theme.fg("dim", `${hunks} hunk${hunks !== 1 ? "s" : ""}`));
	return parts.join(theme.fg("dim", " / "));
}

interface DiffSegment {
	lines: string[];
	isChange: boolean;
	isEllipsis: boolean;
}

function parseDiffSegments(lines: string[]): DiffSegment[] {
	const segments: DiffSegment[] = [];
	let current: DiffSegment | null = null;

	for (const line of lines) {
		const isChange = line.startsWith("+") || line.startsWith("-");
		const isEllipsis = line.trimStart().startsWith("...");

		if (isEllipsis) {
			if (current) segments.push(current);
			segments.push({ lines: [line], isChange: false, isEllipsis: true });
			current = null;
		} else if (!current || current.isChange !== isChange) {
			if (current) segments.push(current);
			current = { lines: [line], isChange, isEllipsis: false };
		} else {
			current.lines.push(line);
		}
	}

	if (current) segments.push(current);
	return segments;
}

export function truncateDiffByHunk(
	diffText: string,
	maxHunks: number,
	maxLines: number,
): { text: string; hiddenHunks: number; hiddenLines: number } {
	const lines = diffText ? diffText.split("\n") : [];
	const totalStats = getDiffStats(diffText);

	if (lines.length <= maxLines && totalStats.hunks <= maxHunks) {
		return { text: diffText, hiddenHunks: 0, hiddenLines: 0 };
	}

	const segments = parseDiffSegments(lines);

	const changeSegments = segments.filter(s => s.isChange);
	const changeLineCount = changeSegments.reduce((sum, s) => sum + s.lines.length, 0);

	if (changeLineCount > maxLines) {
		const kept: string[] = [];
		let keptHunks = 0;

		for (const seg of segments) {
			if (seg.isChange) {
				keptHunks++;
				if (keptHunks > maxHunks) break;
			}
			kept.push(...seg.lines);
			if (kept.length >= maxLines) break;
		}

		const keptStats = getDiffStats(kept.join("\n"));
		return {
			text: kept.join("\n"),
			hiddenHunks: Math.max(0, totalStats.hunks - keptStats.hunks),
			hiddenLines: Math.max(0, lines.length - kept.length),
		};
	}

	const contextBudget = maxLines - changeLineCount;
	const contextSegments = segments.filter(s => !s.isChange && !s.isEllipsis);
	const totalContextLines = contextSegments.reduce((sum, s) => sum + s.lines.length, 0);

	const kept: string[] = [];
	let keptHunks = 0;

	if (totalContextLines <= contextBudget) {
		for (const seg of segments) {
			if (seg.isChange) {
				keptHunks++;
				if (keptHunks > maxHunks) break;
			}
			kept.push(...seg.lines);
		}
	} else {
		const contextRatio = contextSegments.length > 0 ? contextBudget / totalContextLines : 0;

		for (let i = 0; i < segments.length; i++) {
			const seg = segments[i];

			if (seg.isChange) {
				keptHunks++;
				if (keptHunks > maxHunks) break;
				kept.push(...seg.lines);
			} else if (seg.isEllipsis) {
				kept.push(...seg.lines);
			} else {
				const allowedLines = Math.max(1, Math.floor(seg.lines.length * contextRatio));
				const isBeforeChange = segments[i + 1]?.isChange;
				const isAfterChange = segments[i - 1]?.isChange;

				if (isBeforeChange && isAfterChange) {
					const half = Math.ceil(allowedLines / 2);
					if (seg.lines.length > allowedLines) {
						kept.push(...seg.lines.slice(0, half));
						kept.push(seg.lines[0].replace(/^(\s*\d*\s*).*/, "$1..."));
						kept.push(...seg.lines.slice(-half));
					} else {
						kept.push(...seg.lines);
					}
				} else if (isBeforeChange) {
					kept.push(...seg.lines.slice(-allowedLines));
				} else if (isAfterChange) {
					kept.push(...seg.lines.slice(0, allowedLines));
				} else {
					kept.push(...seg.lines.slice(0, Math.min(allowedLines, 2)));
				}
			}
		}
	}

	const keptStats = getDiffStats(kept.join("\n"));
	return {
		text: kept.join("\n"),
		hiddenHunks: Math.max(0, totalStats.hunks - keptStats.hunks),
		hiddenLines: Math.max(0, lines.length - kept.length),
	};
}

// =============================================================================
// Path Utilities
// =============================================================================

export function shortenPath(filePath: string, homeDir?: string): string {
	const home = homeDir ?? os.homedir();
	if (home && filePath.startsWith(home)) {
		return `~${filePath.slice(home.length)}`;
	}
	return filePath;
}

export function formatToolWorkingDirectory(workdir: string | undefined, projectDir: string): string | undefined {
	if (!workdir) return undefined;
	const resolvedProjectDir = path.resolve(projectDir);
	const resolvedWorkdir = path.resolve(projectDir, workdir);
	if (resolvedWorkdir === resolvedProjectDir) {
		return undefined;
	}
	const relativePath = path.relative(resolvedProjectDir, resolvedWorkdir);
	const isWithinProject =
		relativePath.length > 0 && !relativePath.startsWith("..") && !relativePath.startsWith(`..${path.sep}`);
	const displayWorkdir = isWithinProject ? relativePath : shortenPath(resolvedWorkdir);
	return replaceTabs(displayWorkdir);
}

export function formatScreenshot(opts: {
	saveFullRes: boolean;
	savedMimeType: string;
	savedByteLength: number;
	dest: string;
	resized: ResizedImage;
}): string[] {
	const lines = ["Screenshot captured"];
	if (opts.saveFullRes) {
		lines.push(
			`Saved: ${opts.savedMimeType} (${(opts.savedByteLength / 1024).toFixed(2)} KB) to ${shortenPath(opts.dest)}`,
		);
		lines.push(
			`Model: ${opts.resized.mimeType} (${(opts.resized.buffer.length / 1024).toFixed(2)} KB, ${opts.resized.width}x${opts.resized.height})`,
		);
	} else {
		lines.push(`Format: ${opts.resized.mimeType} (${(opts.resized.buffer.length / 1024).toFixed(2)} KB)`);
		lines.push(`Dimensions: ${opts.resized.width}x${opts.resized.height}`);
	}
	const dimensionNote = formatDimensionNote(opts.resized);
	if (dimensionNote) {
		lines.push(dimensionNote);
	}
	return lines;
}

export function wrapBrackets(text: string, theme: Theme): string {
	return `${theme.format.bracketLeft}${text}${theme.format.bracketRight}`;
}

export const PARSE_ERRORS_LIMIT = 20;

export function dedupeParseErrors(errors: string[] | undefined): string[] {
	if (!errors || errors.length === 0) return [];
	const seen = new Set<string>();
	const deduped: string[] = [];
	for (const error of errors) {
		if (seen.has(error)) continue;
		seen.add(error);
		deduped.push(error);
	}
	return deduped;
}

export function formatParseErrors(errors: string[], total?: number): string[] {
	const deduped = dedupeParseErrors(errors);
	if (deduped.length === 0) return [];
	const fullCount = total ?? deduped.length;
	const capped = deduped.slice(0, PARSE_ERRORS_LIMIT);
	const header = fullCount > capped.length ? `Parse issues (${capped.length} / ${fullCount}):` : "Parse issues:";
	return [header, ...capped.map(err => `- ${err}`)];
}

/**
 * Cap an upstream parse-error list to {@link PARSE_ERRORS_LIMIT} unique entries,
 * preserving the original deduplicated total. Use this at the source so tool
 * details never carry thousands of per-file parse errors into traces or
 * renderers.
 */
export function capParseErrors(
	errors: string[] | undefined,
	limit: number = PARSE_ERRORS_LIMIT,
): { errors: string[]; total: number } {
	const deduped = dedupeParseErrors(errors);
	return { errors: deduped.slice(0, limit), total: deduped.length };
}

// =============================================================================
// Renderer helpers shared by search / find / ast tools
// =============================================================================

/**
 * Group `rawLines` by blank-line separators, mirroring the historical search /
 * ast-grep / ast-edit renderer behavior: if any blank line is present, splits on
 * runs of blank lines; otherwise collapses non-empty lines into a single group.
 */
export function splitGroupsByBlankLine(rawLines: string[]): string[][] {
	const hasSeparators = rawLines.some(line => line.trim().length === 0);
	const groups: string[][] = [];
	if (hasSeparators) {
		let current: string[] = [];
		for (const line of rawLines) {
			if (line.trim().length === 0) {
				if (current.length > 0) {
					groups.push(current);
					current = [];
				}
				continue;
			}
			current.push(line);
		}
		if (current.length > 0) groups.push(current);
	} else {
		const nonEmpty = rawLines.filter(line => line.trim().length > 0);
		if (nonEmpty.length > 0) {
			groups.push(nonEmpty);
		}
	}
	return groups;
}

/**
 * Standard width+expand keyed render cache used by every search-style tool
 * renderer. `compute` re-runs only when the cache key changes; the returned
 * Component is the canonical `{ render, invalidate }` pair.
 */
export function createCachedComponent(
	getExpanded: () => boolean,
	compute: (width: number, expanded: boolean) => string[],
): Component {
	let cached: { key: bigint; lines: string[] } | undefined;
	return {
		render(width: number): string[] {
			const expanded = getExpanded();
			const key = new Hasher().bool(expanded).u32(width).digest();
			if (cached?.key === key) return cached.lines;
			const lines = compute(width, expanded);
			cached = { key, lines };
			return lines;
		},
		invalidate() {
			cached = undefined;
		},
	};
}

/**
 * Append the indented bullet list of parse errors (capped at
 * {@link PARSE_ERRORS_LIMIT}) to `lines`, with an overflow summary line if the
 * total exceeds the cap. No-op when `parseErrors` is empty.
 */
export function appendParseErrorsBulletList(
	lines: string[],
	parseErrors: readonly string[] | undefined,
	theme: Theme,
	total?: number,
): void {
	if (!parseErrors || parseErrors.length === 0) return;
	const fullCount = total ?? parseErrors.length;
	const capped = parseErrors.slice(0, PARSE_ERRORS_LIMIT);
	for (const err of capped) {
		lines.push(theme.fg("warning", `  - ${err}`));
	}
	if (fullCount > capped.length) {
		lines.push(theme.fg("dim", `  … ${fullCount - capped.length} more`));
	}
}

/**
 * Human-readable summary string for the parse-issues count, capped by
 * {@link PARSE_ERRORS_LIMIT}.
 */
export function formatParseErrorsCountLabel(parseErrors: readonly string[], total?: number): string {
	const fullCount = total ?? parseErrors.length;
	return fullCount > PARSE_ERRORS_LIMIT
		? `${PARSE_ERRORS_LIMIT} / ${fullCount} parse issues`
		: `${fullCount} parse issue${fullCount !== 1 ? "s" : ""}`;
}

// =============================================================================
// LSP Batching
// =============================================================================

const LSP_BATCH_TOOLS = new Set(["edit", "write"]);

export interface LspBatchRequest {
	id: string;
	flush: boolean;
}

export function getLspBatchRequest(toolCall: ToolCallContext | undefined): LspBatchRequest | undefined {
	if (!toolCall) {
		return undefined;
	}
	const hasOtherWrites = toolCall.toolCalls.some(
		(call, index) => index !== toolCall.index && LSP_BATCH_TOOLS.has(call.name),
	);
	if (!hasOtherWrites) {
		return undefined;
	}
	const hasLaterWrites = toolCall.toolCalls.slice(toolCall.index + 1).some(call => LSP_BATCH_TOOLS.has(call.name));
	return { id: toolCall.batchId, flush: !hasLaterWrites };
}