import { readFileSync, writeFileSync, existsSync, appendFileSync } from "node:fs";
import { type Config } from "./types";

export function sleep(ms: number): Promise<void> {
    return new Promise((r) => setTimeout(r, ms));
}

export function readFile(filePath: string): string[] {
    if (!existsSync(filePath)) return [];
    return readFileSync(filePath, "utf-8")
        .split("\n")
        .map((s) => s.trim())
        .filter((s) => s && !s.startsWith("#"));
}

// NEW: System Log Writer
export function appendLog(fileName: string, message: string): void {
    try {
        const timestamp = new Date().toISOString();
        // Simple log line
        const logLine = `[${timestamp}] ${message}\n`;
        appendFileSync(fileName, logLine, "utf-8");
    } catch (err) {
        // Fail silently or print to console if debugging
    }
}

export function formatElapsed(start: Date): string {
    const diff = Math.max(0, Math.floor((Date.now() - start.getTime()) / 1000));
    const hrs = Math.floor(diff / 3600);
    const mins = Math.floor((diff % 3600) / 60);
    const secs = diff % 60;
    if (hrs > 0) return `${hrs}h ${mins}m`;
    if (mins > 0) return `${mins}m ${secs}s`;
    return `${secs}s`;
}

export function rid(length: number = 6): string {
    return [...Array(length)].map(() => Math.random().toString(36)[2]).join("");
}

// --- Config Persistence (Saving/Loading settings) ---

const CONFIG_FILE = "config.json";

export function loadConfig(defaults: Config): Config {
    try {
        if (existsSync(CONFIG_FILE)) {
            const fileContent = readFileSync(CONFIG_FILE, "utf-8");
            const saved = JSON.parse(fileContent);
            // Merge saved data with defaults
            return { ...defaults, ...saved };
        }
    } catch (err) {
        console.error("⚠️ Could not load config.json, using defaults.");
    }
    return defaults;
}

export function saveConfigToFile(config: Config): void {
    try {
        writeFileSync(CONFIG_FILE, JSON.stringify(config, null, 2), "utf-8");
    } catch (err) {
        console.error("❌ Failed to save config:", err);
    }
}