/**
 * model-flash: when you cycle models with Ctrl+P (or shift+Ctrl+P),
 * flash the current model name in BIG letters above the editor for ~1s.
 *
 * Implemented as a non-capturing widget (ctx.ui.setWidget) so rapid
 * Ctrl+P keystrokes are never queued behind the popup — the widget just
 * re-renders in place as the model changes.
 *
 * Usage:
 *   pi -e ./model-flash.ts
 * or add this file to your settings under extensions.
 */

import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";

// ---------------------------------------------------------------------------
// Tiny 5-row block font. Each glyph is 5 rows tall, columns vary (mostly 4-5).
// Add a 1-col gap between glyphs when rendering.
// '#' = filled cell, ' ' = empty.
// ---------------------------------------------------------------------------
const FONT: Record<string, string[]> = {
	A: [" ## ", "#  #", "####", "#  #", "#  #"],
	B: ["### ", "#  #", "### ", "#  #", "### "],
	C: [" ###", "#   ", "#   ", "#   ", " ###"],
	D: ["### ", "#  #", "#  #", "#  #", "### "],
	E: ["####", "#   ", "### ", "#   ", "####"],
	F: ["####", "#   ", "### ", "#   ", "#   "],
	G: [" ###", "#   ", "# ##", "#  #", " ###"],
	H: ["#  #", "#  #", "####", "#  #", "#  #"],
	I: ["###", " # ", " # ", " # ", "###"],
	J: ["####", "   #", "   #", "#  #", " ## "],
	K: ["#  #", "# # ", "##  ", "# # ", "#  #"],
	L: ["#   ", "#   ", "#   ", "#   ", "####"],
	M: ["#   #", "## ##", "# # #", "#   #", "#   #"],
	N: ["#  #", "## #", "# ##", "#  #", "#  #"],
	O: [" ## ", "#  #", "#  #", "#  #", " ## "],
	P: ["### ", "#  #", "### ", "#   ", "#   "],
	Q: [" ## ", "#  #", "#  #", "# ##", " ###"],
	R: ["### ", "#  #", "### ", "# # ", "#  #"],
	S: [" ###", "#   ", " ## ", "   #", "### "],
	T: ["###", " # ", " # ", " # ", " # "],
	U: ["#  #", "#  #", "#  #", "#  #", " ## "],
	V: ["#  #", "#  #", "#  #", " ## ", " ## "],
	W: ["#   #", "#   #", "# # #", "## ##", "#   #"],
	X: ["#  #", " ## ", " ## ", " ## ", "#  #"],
	Y: ["#  #", " ## ", " ## ", " #  ", " #  "],
	Z: ["####", "   #", "  # ", " #  ", "####"],
	"0": [" ## ", "#  #", "#  #", "#  #", " ## "],
	"1": [" # ", "## ", " # ", " # ", "###"],
	"2": ["### ", "   #", " ## ", "#   ", "####"],
	"3": ["### ", "   #", " ## ", "   #", "### "],
	"4": ["#  #", "#  #", "####", "   #", "   #"],
	"5": ["####", "#   ", "### ", "   #", "### "],
	"6": [" ###", "#   ", "### ", "#  #", " ## "],
	"7": ["####", "   #", "  # ", " #  ", " #  "],
	"8": [" ## ", "#  #", " ## ", "#  #", " ## "],
	"9": [" ## ", "#  #", " ###", "   #", "### "],
	"-": ["    ", "    ", "####", "    ", "    "],
	"_": ["    ", "    ", "    ", "    ", "####"],
	".": ["   ", "   ", "   ", "   ", " # "],
	"/": ["   #", "  # ", " #  ", " #  ", "#   "],
	":": ["   ", " # ", "   ", " # ", "   "],
	" ": ["  ", "  ", "  ", "  ", "  "],
};

const BLOCK = "█";

function renderBig(text: string): string[] {
	const chars = [...text.toUpperCase()].map((c) => FONT[c] ?? FONT["-"]!);
	const rows: string[] = [];
	for (let r = 0; r < 5; r++) {
		let line = "";
		for (let i = 0; i < chars.length; i++) {
			const glyph = chars[i]!;
			line += glyph[r]!.replace(/#/g, BLOCK);
			if (i < chars.length - 1) line += " ";
		}
		rows.push(line);
	}
	return rows;
}

function maxLineWidth(lines: string[]): number {
	let w = 0;
	for (const l of lines) if (l.length > w) w = l.length;
	return w;
}

// ---------------------------------------------------------------------------
// Extension entry point.
//
// Renders the flash as a non-capturing widget above the editor. Each cycle
// just replaces the widget content; the timer schedules removal ~1s after
// the last cycle.
// ---------------------------------------------------------------------------
const WIDGET_KEY = "model-flash";
const FLASH_MS = 1000;

export default function (pi: ExtensionAPI) {
	let timer: NodeJS.Timeout | null = null;

	pi.on("model_select", async (event, ctx) => {
		// Only flash on user-driven cycling. Skip /model "set" and "restore".
		if (event.source !== "cycle") return;

		const { model } = event;
		const theme = ctx.ui.theme;

		const banner = renderBig(model.id);
		const bannerW = maxLineWidth(banner);

		// Center each banner row and the subtitle within bannerW.
		const center = (raw: string, styled: string): string => {
			const leftPad = Math.max(0, Math.floor((bannerW - raw.length) / 2));
			return " ".repeat(leftPad) + styled;
		};

		const lines: string[] = [
			...banner.map((raw) => center(raw, theme.fg("accent", theme.bold(raw)))),
			center(model.provider, theme.fg("muted", model.provider)),
		];

		ctx.ui.setWidget(WIDGET_KEY, lines);

		if (timer) clearTimeout(timer);
		timer = setTimeout(() => {
			timer = null;
			ctx.ui.setWidget(WIDGET_KEY, undefined);
		}, FLASH_MS);
	});
}