/**
 * Cross-Platform Global Object Access
 *
 * Provides unified access to global objects across different JavaScript environments:
 * - Browser (window)
 * - Node.js (global)
 * - Web Workers (self)
 * - Modern environments (globalThis)
 * - Fallback for edge cases
 */

/**
 * Safely test if an object could be a global object
 * @param {any} obj - Object to test
 * @returns {any} The object if it has Math, undefined otherwise
 */
function testGlobalCandidate(obj) {
  return obj && obj.Math === Math ? obj : undefined;
}

/**
 * Cached reference to the global object
 * Uses a cascade of checks to find the appropriate global object:
 * 1. globalThis (ES2020 standard)
 * 2. window (browser)
 * 3. self (web workers, service workers)
 * 4. global (Node.js)
 * 5. Function constructor fallback
 * 6. Empty object fallback
 */
const GLOBAL_OBJ =
  (typeof globalThis === "object" && testGlobalCandidate(globalThis)) ||
  (typeof window === "object" && testGlobalCandidate(window)) ||
  (typeof self === "object" && testGlobalCandidate(self)) ||
  (typeof global === "object" && testGlobalCandidate(global)) ||
  (() => {
    try {
      // Use Function constructor to access global in strict mode
      return Function("return this")();
    } catch (error) {
      // In case Function constructor is disabled (CSP, etc.)
      return {};
    }
  })();

/**
 * Get the global object for the current environment
 * @returns {Object} Global object (window, global, self, etc.)
 */
function getGlobalObject() {
  return GLOBAL_OBJ;
}

/**
 * Get or create a singleton on the global object
 * Useful for ensuring single instances across different modules
 * @param {string} key - Key to store singleton under
 * @param {Function} factory - Factory function to create the singleton
 * @param {Object} target - Target object (defaults to global)
 * @returns {any} The singleton instance
 */
function getGlobalSingleton(key, factory, target) {
  const globalTarget = target || GLOBAL_OBJ;
  const sentryGlobals = (globalTarget.__SENTRY__ =
    globalTarget.__SENTRY__ || {});

  return sentryGlobals[key] || (sentryGlobals[key] = factory());
}

/**
 * Detect the current JavaScript environment
 * @returns {Object} Environment information
 */
function detectEnvironment() {
  const global = getGlobalObject();

  return {
    // Environment types
    isBrowser:
      typeof window !== "undefined" && typeof window.document !== "undefined",
    isNode:
      typeof global !== "undefined" &&
      global.process &&
      global.process.versions &&
      global.process.versions.node,
    isWebWorker: typeof self !== "undefined" && typeof window === "undefined",
    isServiceWorker:
      typeof self !== "undefined" && typeof self.serviceWorker !== "undefined",
    isDeno: typeof Deno !== "undefined",
    isBun: typeof Bun !== "undefined",

    // Browser specifics
    isElectron:
      typeof global !== "undefined" &&
      global.process &&
      global.process.type === "renderer",
    isWebView:
      typeof window !== "undefined" &&
      (window.ReactNativeWebView ||
        window.webkit?.messageHandlers ||
        window.Android),

    // Runtime capabilities
    hasGlobalThis: typeof globalThis !== "undefined",
    hasWindow: typeof window !== "undefined",
    hasGlobal: typeof global !== "undefined",
    hasSelf: typeof self !== "undefined",
    hasDocument: typeof document !== "undefined",
    hasProcess: typeof process !== "undefined",

    // Console availability
    hasConsole: typeof console !== "undefined",

    // Global object used
    globalObjectName:
      typeof globalThis !== "undefined"
        ? "globalThis"
        : typeof window !== "undefined"
          ? "window"
          : typeof global !== "undefined"
            ? "global"
            : typeof self !== "undefined"
              ? "self"
              : "unknown",
  };
}

/**
 * Get environment-specific information
 * @returns {Object} Detailed environment information
 */
function getEnvironmentInfo() {
  const env = detectEnvironment();
  const global = getGlobalObject();
  const info = { ...env };

  // Add version information where available
  if (env.isNode) {
    info.nodeVersion = global.process?.versions?.node;
    info.v8Version = global.process?.versions?.v8;
  }

  if (env.isBrowser) {
    info.userAgent =
      typeof navigator !== "undefined" ? navigator.userAgent : undefined;
    info.language =
      typeof navigator !== "undefined" ? navigator.language : undefined;
  }

  if (env.isDeno) {
    info.denoVersion = Deno?.version?.deno;
  }

  if (env.isBun) {
    info.bunVersion = Bun?.version;
  }

  return info;
}

/**
 * Safely access nested properties on global object
 * @param {string} path - Dot-separated path to property
 * @returns {any} Property value or undefined
 */
function getGlobalProperty(path) {
  const parts = path.split(".");
  let current = getGlobalObject();

  for (const part of parts) {
    if (current == null || typeof current !== "object") {
      return undefined;
    }
    current = current[part];
  }

  return current;
}

/**
 * Safely set nested properties on global object
 * @param {string} path - Dot-separated path to property
 * @param {any} value - Value to set
 * @returns {boolean} True if successful
 */
function setGlobalProperty(path, value) {
  try {
    const parts = path.split(".");
    const propertyName = parts.pop();
    let current = getGlobalObject();

    for (const part of parts) {
      if (current[part] == null) {
        current[part] = {};
      }
      current = current[part];
    }

    current[propertyName] = value;
    return true;
  } catch (error) {
    return false;
  }
}

/**
 * Check if running in a sandboxed environment
 * @returns {boolean} True if environment appears sandboxed
 */
function isSandboxed() {
  const global = getGlobalObject();

  // Check for common sandbox restrictions
  const restrictions = [
    // No eval
    () => {
      try {
        eval("1");
        return false;
      } catch (e) {
        return true;
      }
    },

    // No Function constructor
    () => {
      try {
        new Function("return 1")();
        return false;
      } catch (e) {
        return true;
      }
    },

    // Limited global properties
    () => {
      const expectedProps = ["Object", "Array", "String", "Number", "Boolean"];
      return !expectedProps.every((prop) => typeof global[prop] === "function");
    },
  ];

  return restrictions.some((check) => {
    try {
      return check();
    } catch (e) {
      return true;
    }
  });
}

/**
 * Get safe globals that should be available in most environments
 * @returns {Object} Safe global references
 */
function getSafeGlobals() {
  const global = getGlobalObject();

  return {
    Object: global.Object,
    Array: global.Array,
    String: global.String,
    Number: global.Number,
    Boolean: global.Boolean,
    Date: global.Date,
    RegExp: global.RegExp,
    JSON: global.JSON,
    Math: global.Math,
    parseInt: global.parseInt,
    parseFloat: global.parseFloat,
    isNaN: global.isNaN,
    isFinite: global.isFinite,
    console: global.console,
    setTimeout: global.setTimeout,
    clearTimeout: global.clearTimeout,
    setInterval: global.setInterval,
    clearInterval: global.clearInterval,
  };
}

module.exports = {
  GLOBAL_OBJ,
  getGlobalObject,
  getGlobalSingleton,
  detectEnvironment,
  getEnvironmentInfo,
  getGlobalProperty,
  setGlobalProperty,
  isSandboxed,
  getSafeGlobals,
};