/**
 * Centralized configuration management for the application.
 * This file defines the schema and provides a type-safe way to access environment variables.
 */
import dotenv from 'dotenv';
import path from 'path';

// Load .env file in development (server-side only)
if (typeof window === 'undefined' && process.env.NODE_ENV !== 'production') {
  dotenv.config({ path: path.resolve(process.cwd(), '.env') });
}

const getEnv = (key: string, defaultValue?: string): string | undefined => {
  // In the browser, we can only access NEXT_PUBLIC_ variables
  if (typeof window !== 'undefined') {
    if (!key.startsWith('NEXT_PUBLIC_')) {
      return defaultValue;
    }
    return (process.env as any)[key] || defaultValue;
  }

  if (typeof process === 'undefined') return defaultValue;
  
  // In Docker/Production, variables are in process.env
  // In local development, they might be in .env
  const value = process.env[key];
  
  // Check for quoted values (common when passed via SSH/Docker)
  if (typeof value === 'string') {
    const trimmed = value.trim();
    if ((trimmed.startsWith("'") && trimmed.endsWith("'")) || 
        (trimmed.startsWith('"') && trimmed.endsWith('"'))) {
      return trimmed.slice(1, -1);
    }
    return trimmed;
  }

  return defaultValue;
};

export const config = {
  env: getEnv('NODE_ENV', 'development'),
  isProduction: getEnv('NODE_ENV') === 'production',
  isDevelopment: getEnv('NODE_ENV') === 'development',
  isTest: getEnv('NODE_ENV') === 'test',

  baseUrl: getEnv('NEXT_PUBLIC_BASE_URL', 'http://localhost:3000'),

  analytics: {
    umami: {
      websiteId: getEnv('NEXT_PUBLIC_UMAMI_WEBSITE_ID'),
      scriptUrl: getEnv('NEXT_PUBLIC_UMAMI_SCRIPT_URL', 'https://analytics.infra.mintel.me/script.js'),
      // The proxied path used in the frontend
      proxyPath: '/stats/script.js',
      enabled: Boolean(getEnv('NEXT_PUBLIC_UMAMI_WEBSITE_ID')),
    },
  },

  errors: {
    glitchtip: {
      // Use SENTRY_DSN for both server and client (proxied)
      dsn: getEnv('SENTRY_DSN'),
      // The proxied origin used in the frontend
      proxyPath: '/errors',
      enabled: Boolean(getEnv('SENTRY_DSN')),
    },
  },

  cache: {
    redis: {
      url: getEnv('REDIS_URL'),
      keyPrefix: getEnv('REDIS_KEY_PREFIX', 'klz:'),
      enabled: Boolean(getEnv('REDIS_URL')),
    },
  },

  logging: {
    level: getEnv('LOG_LEVEL', 'info'),
  },

  mail: {
    host: getEnv('MAIL_HOST'),
    port: parseInt(getEnv('MAIL_PORT', '587')!, 10),
    user: getEnv('MAIL_USERNAME'),
    pass: getEnv('MAIL_PASSWORD'),
    from: getEnv('MAIL_FROM'),
    recipients: getEnv('MAIL_RECIPIENTS', '')?.split(',').filter(Boolean) || [],
  },
} as const;

/**
 * Helper to get a masked version of the config for logging.
 */
export function getMaskedConfig() {
  const mask = (val: string | undefined) => (val ? `***${val.slice(-4)}` : 'not set');

  return {
    env: config.env,
    baseUrl: config.baseUrl,
    analytics: {
      umami: {
        websiteId: mask(config.analytics.umami.websiteId),
        scriptUrl: config.analytics.umami.scriptUrl,
        enabled: config.analytics.umami.enabled,
      },
    },
    errors: {
      glitchtip: {
        dsn: mask(config.errors.glitchtip.dsn),
        enabled: config.errors.glitchtip.enabled,
      },
    },
    cache: {
      redis: {
        url: mask(config.cache.redis.url),
        keyPrefix: config.cache.redis.keyPrefix,
        enabled: config.cache.redis.enabled,
      },
    },
    logging: {
      level: config.logging.level,
    },
    mail: {
      host: config.mail.host,
      port: config.mail.port,
      user: mask(config.mail.user),
      from: config.mail.from,
      recipients: config.mail.recipients,
    },
  };
}

/**
 * Validates that all required environment variables are set.
 * Should be called on server startup.
 */
export function validateConfig() {
  if (config.isProduction && typeof window === 'undefined') {
    const required = [
      'NEXT_PUBLIC_BASE_URL',
    ];

    for (const key of required) {
      const value = getEnv(key);
      if (!value) {
        // In Next.js, process.env might not be a real object with enumerable keys in the bundle
        // so we check the specific key directly
        const rawValue = process.env[key];
        throw new Error(`Missing required environment variable: ${key}. (getEnv: "${value}", process.env: "${rawValue}"). If this is set in your environment, ensure it is not being shadowed or cleared by the container runtime.`);
      }
    }
  }
}