import * as fs from 'fs';
import * as path from 'path';
import * as os from 'os';
import yaml from 'js-yaml';

export interface Config {
  privateKey?: string;
  network?: string;
  networks?: {
    [network: string]: {
      schemaUID?: string;
      rpcUrl?: string;
      easContractAddress?: string;
      schemaRegistryAddress?: string;
    };
  };
}

/**
 * Load config from multiple sources (priority order):
 * 1. Custom config path (--config flag)
 * 2. ./.atnotary.yaml (current directory)
 * 3. ~/.atnotary.yaml (home directory)
 * 4. .env file (fallback)
 */
export function loadConfig(customPath?: string): Config {
  let config: Config = {};

  // Try custom path first
  if (customPath) {
    if (fs.existsSync(customPath)) {
      config = loadYamlConfig(customPath);
      return config;
    } else {
      throw new Error(`Config file not found: ${customPath}`);
    }
  }

  // Try current directory
  const localConfig = path.join(process.cwd(), '.atnotary.yaml');
  if (fs.existsSync(localConfig)) {
    config = loadYamlConfig(localConfig);
    return config;
  }

  // Try home directory
  const homeConfig = path.join(os.homedir(), '.atnotary.yaml');
  if (fs.existsSync(homeConfig)) {
    config = loadYamlConfig(homeConfig);
    return config;
  }

  return config;
}

function loadYamlConfig(filePath: string): Config {
  try {
    const fileContents = fs.readFileSync(filePath, 'utf8');
    const config = yaml.load(fileContents) as Config;
    return config;
  } catch (error: any) {
    throw new Error(`Failed to load config from ${filePath}: ${error.message}`);
  }
}

/**
 * Get schema UID for specific network
 */
export function getSchemaUID(config: Config, network: string): string | undefined {
  return config.networks?.[network]?.schemaUID;
}

/**
 * Create default config template
 */
export function createConfigTemplate(outputPath: string): void {
  const template = `# atnotary configuration
# Private key for signing transactions (required for notarization)
privateKey: "0x..."

# Default network (sepolia, base-sepolia, base)
network: sepolia

# Network-specific configuration
networks:
  sepolia:
    schemaUID: "0x..."
    # Optional: custom RPC URL
    # rpcUrl: "https://..."
    
  base-sepolia:
    schemaUID: "0x..."
    # rpcUrl: "https://sepolia.base.org"
    
  base:
    schemaUID: "0x..."
    # rpcUrl: "https://mainnet.base.org"
`;

  fs.writeFileSync(outputPath, template, 'utf8');
}