import { app } from "electron";
import * as fs from "fs";
import * as path from "path";

export class LogService {
    private static instance: LogService;
    private logPath: string;

    private constructor() {
        // Create logs directory in userData
        const userDataPath = app.getPath("userData");
        const logsDir = path.join(userDataPath, "logs");

        if (!fs.existsSync(logsDir)) {
            fs.mkdirSync(logsDir, { recursive: true });
        }

        // Monthly log file
        const now = new Date();
        const year = now.getFullYear();
        const month = String(now.getMonth() + 1).padStart(2, "0");
        const monthString = `${year}-${month}`; // YYYY-MM
        this.logPath = path.join(logsDir, `app_${monthString}.log`);

        this.info(`--- Log initialized at ${now.toISOString()} ---`);
        console.log(`Log file: ${this.logPath}`);
    }

    /**
     * Garantizar que sea singleton
     * @returns
     */
    public static getInstance(): LogService {
        if (!LogService.instance) {
            LogService.instance = new LogService();
        }
        return LogService.instance;
    }

    public info(message: string): void {
        this.write("INFO", message);
    }

    public error(message: string, error?: unknown): void {
        const errorDetail = error ? ` | Details: ${JSON.stringify(error)}` : "";
        this.write("ERROR", `${message}${errorDetail}`);
    }

    public logOperation(
        operation: string,
        data: unknown,
        result?: unknown,
    ): void {
        const entry = {
            operation,
            data,
            result,
            timestamp: new Date().toISOString(),
        };
        this.write("OP", JSON.stringify(entry));
    }

    private write(level: string, message: string): void {
        const timestamp = new Date().toISOString();
        const logEntry = `[${timestamp}] [${level}] ${message}\n`;

        try {
            fs.appendFileSync(this.logPath, logEntry, "utf8");
        } catch (err) {
            console.error("Failed to write to log file:", err);
        }
    }
}

export const logger = LogService.getInstance();