/**
 * Progress bar rendering with discrete block characters.
 *
 * Renders ▁▂▃▄▅▆▇█ glyphs on a dim background track.
 */

import type { Theme, ThemeColor } from "@earendil-works/pi-coding-agent";

const GLYPHS = [" ", "▁", "▂", "▃", "▄", "▅", "▆", "▇", "█"];
const MAX_LEVEL = GLYPHS.length - 1;
const RESET = "\x1b[39m\x1b[49m";

/** Render discrete block characters with dim background track. */
export function renderBlocksBar(
	pct: number,
	width: number,
	theme: Theme,
	color: ThemeColor,
): string {
	const clamped = Math.max(0, Math.min(100, pct));
	const filledFloat = (clamped / 100) * width;
	const dimBg = fgToBgAnsi(theme.getFgAnsi("dim"));
	const fgColor = theme.getFgAnsi(color);

	const result: string[] = [];
	for (let i = 0; i < width; i++) {
		const blockFill = Math.max(0, Math.min(1, filledFloat - i));
		const level = Math.round(blockFill * MAX_LEVEL);
		const glyph = GLYPHS[level];
		result.push(
			level > 0
				? `${dimBg}${fgColor}${glyph}${RESET}`
				: `${dimBg}${glyph}${RESET}`,
		);
	}

	return result.join("");
}

function fgToBgAnsi(fgAnsi: string): string {
	return fgAnsi.replace("\x1b[38;", "\x1b[48;");
}