import { appendFileSync, existsSync, mkdirSync } from "fs";
import { randomUUID } from "crypto";
import { join } from "path";

export const SKILL_NAME = "extract-invoice";
export const SESSION_ID = randomUUID().slice(0, 8);
export const SESSION_TIMESTAMP = new Date()
  .toISOString()
  .replace(/[:.]/g, "_")
  .replace(/-/g, "_")
  .slice(0, 19)
  .toLowerCase();

export const SKILLS_OUTPUT_DIR = process.env.SKILLS_OUTPUT_DIR || join(process.cwd(), ".skills");
export const EXPORTS_DIR = join(SKILLS_OUTPUT_DIR, "exports", SKILL_NAME, SESSION_ID);
export const LOGS_DIR = join(SKILLS_OUTPUT_DIR, "logs", SKILL_NAME);
export const OPENAI_API_URL = "https://api.openai.com/v1/chat/completions";

export function getOpenAIApiKey(): string | undefined {
  return process.env.OPENAI_API_KEY;
}

export function ensureDir(dir: string): void {
  if (!existsSync(dir)) {
    mkdirSync(dir, { recursive: true });
  }
}

export function log(message: string, level: "info" | "error" | "success" | "warn" = "info"): void {
  const timestamp = new Date().toISOString();
  const logFile = join(LOGS_DIR, `log_${SESSION_TIMESTAMP}_${SESSION_ID}.log`);

  ensureDir(LOGS_DIR);

  const logEntry = `[${timestamp}] [${level.toUpperCase()}] ${message}\n`;
  appendFileSync(logFile, logEntry);

  const prefixes: Record<string, string> = {
    info: "[INFO]",
    error: "[ERROR]",
    success: "[SUCCESS]",
    warn: "[WARN]",
  };

  console.log(`${prefixes[level]} ${message}`);
}