import { visibleWidth } from "@earendil-works/pi-tui";

export interface CursorConfig {
	blinkMs: number;
	prompt: string;
	symbol: string;
	color: string;
	working: {
		symbol: string;
	};
}

export const DEFAULT_CURSOR_CONFIG: Readonly<CursorConfig> = {
	blinkMs: 700,
	prompt: ">: ",
	symbol: "█",
	color: "accent",
	working: {
		symbol: "░",
	},
};

export function defaultCursorConfig(): CursorConfig {
	return { ...DEFAULT_CURSOR_CONFIG, working: { ...DEFAULT_CURSOR_CONFIG.working } };
}

function isRecord(value: unknown): value is Record<string, unknown> {
	return typeof value === "object" && value !== null && !Array.isArray(value);
}

function isCursorSymbol(value: unknown): value is string {
	return typeof value === "string" && [...value].length === 1 && visibleWidth(value) === 1 && !/[\r\n]/.test(value);
}

function isPrompt(value: unknown): value is string {
	return typeof value === "string" && value.length <= 24 && !/[\r\n]/.test(value);
}

export function isHexColor(value: unknown): value is string {
	return typeof value === "string" && /^#[0-9a-f]{6}$/i.test(value);
}

function isColor(value: unknown): value is string {
	return isHexColor(value) || (typeof value === "string" && /^[a-z][a-zA-Z]*$/.test(value));
}

export function parseCursorConfig(value: unknown): CursorConfig {
	if (!isRecord(value)) return defaultCursorConfig();

	return {
		blinkMs: typeof value.blinkMs === "number" && Number.isInteger(value.blinkMs) && value.blinkMs >= 0
			? value.blinkMs
			: DEFAULT_CURSOR_CONFIG.blinkMs,
		prompt: isPrompt(value.prompt) ? value.prompt : DEFAULT_CURSOR_CONFIG.prompt,
		symbol: isCursorSymbol(value.symbol) ? value.symbol : DEFAULT_CURSOR_CONFIG.symbol,
		color: isColor(value.color) ? value.color : DEFAULT_CURSOR_CONFIG.color,
		working: isRecord(value.working) && isCursorSymbol(value.working.symbol)
			? { symbol: value.working.symbol }
			: { ...DEFAULT_CURSOR_CONFIG.working },
	};
}