import fs from "node:fs";
import path from "node:path";
import { paperclipConfigSchema, type PaperclipConfig } from "./schema.js";

const DEFAULT_CONFIG_PATH = ".paperclip/config.json";

export function resolveConfigPath(overridePath?: string): string {
  if (overridePath) return path.resolve(overridePath);
  if (process.env.PAPERCLIP_CONFIG) return path.resolve(process.env.PAPERCLIP_CONFIG);
  return path.resolve(process.cwd(), DEFAULT_CONFIG_PATH);
}

export function readConfig(configPath?: string): PaperclipConfig | null {
  const filePath = resolveConfigPath(configPath);
  if (!fs.existsSync(filePath)) return null;
  const raw = JSON.parse(fs.readFileSync(filePath, "utf-8"));
  return paperclipConfigSchema.parse(raw);
}

export function writeConfig(
  config: PaperclipConfig,
  configPath?: string,
): void {
  const filePath = resolveConfigPath(configPath);
  const dir = path.dirname(filePath);
  fs.mkdirSync(dir, { recursive: true });

  // Backup existing config before overwriting
  if (fs.existsSync(filePath)) {
    const backupPath = filePath + ".backup";
    fs.copyFileSync(filePath, backupPath);
    fs.chmodSync(backupPath, 0o600);
  }

  fs.writeFileSync(filePath, JSON.stringify(config, null, 2) + "\n", {
    mode: 0o600,
  });
}

export function configExists(configPath?: string): boolean {
  return fs.existsSync(resolveConfigPath(configPath));
}