/**
 * Config for pi-peak-hours, read once at extension load from
 * `~/.pi/agent/settings.json` (or `$PI_CODING_AGENT_DIR/agent/settings.json`)
 * under the `peakHours` key. `/reload` recreates the extension and re-reads
 * the config; there is no hot-reload.
 */
import { readFileSync } from "node:fs";
import { homedir } from "node:os";
import { join } from "node:path";
import { SCHEDULES } from "./schedules.ts";

export interface PeakHoursConfig {
	enabled: boolean;
	/** "auto" (system zone) | "UTC" | an IANA zone name, e.g. "Asia/Yekaterinburg". */
	timezone: string;
	/** "peak": hide the widget when everything is off-peak. "always": always show. */
	show: "peak" | "always";
	/** Schedule ids to track. */
	providers: string[];
}

const DEFAULTS: PeakHoursConfig = {
	enabled: true,
	timezone: "auto",
	show: "peak",
	providers: SCHEDULES.map((s) => s.id),
};

const KNOWN_IDS = new Set(SCHEDULES.map((s) => s.id));

function expandTilde(path: string): string {
	if (path === "~") return homedir();
	if (path.startsWith("~/")) return join(homedir(), path.slice(2));
	return path;
}

/** Path of the settings file this extension reads. */
export function settingsPath(): string {
	const envDir = process.env.PI_CODING_AGENT_DIR;
	const base = envDir ? expandTilde(envDir) : join(homedir(), ".pi", "agent");
	return join(base, "settings.json");
}

export function loadConfig(): PeakHoursConfig {
	let section: Record<string, unknown> = {};
	try {
		const raw = JSON.parse(readFileSync(settingsPath(), "utf8")) as unknown;
		if (typeof raw === "object" && raw !== null && typeof (raw as Record<string, unknown>)["peakHours"] === "object") {
			section = (raw as Record<string, unknown>)["peakHours"] as Record<string, unknown>;
		}
	} catch {
		// missing or unreadable settings file → defaults
	}
	const providers = Array.isArray(section.providers)
		? section.providers.filter((p): p is string => typeof p === "string" && KNOWN_IDS.has(p))
		: [];
	return {
		enabled: typeof section.enabled === "boolean" ? section.enabled : DEFAULTS.enabled,
		timezone: typeof section.timezone === "string" ? section.timezone : DEFAULTS.timezone,
		show: section.show === "always" ? "always" : DEFAULTS.show,
		providers: providers.length > 0 ? providers : DEFAULTS.providers,
	};
}