import { PluginMeta } from '@grafana/data';

import { transformPluginSourceForCDN } from '../cdn/utils';
import { resolveWithCache } from '../loader/cache';
import { isHostedOnCDN } from '../loader/utils';

import { SandboxEnvironment } from './types';

function isSameDomainAsHost(url: string): boolean {
  const locationUrl = new URL(window.location.href);
  const paramUrl = new URL(url);
  return locationUrl.host === paramUrl.host;
}

export async function loadScriptIntoSandbox(url: string, meta: PluginMeta, sandboxEnv: SandboxEnvironment) {
  let scriptCode = '';

  // same-domain
  if (isSameDomainAsHost(url)) {
    const response = await fetch(url);
    scriptCode = await response.text();
    scriptCode = patchPluginSourceMap(meta, scriptCode);

    // cdn loaded
  } else if (isHostedOnCDN(url)) {
    const response = await fetch(url);
    scriptCode = await response.text();
    scriptCode = transformPluginSourceForCDN({
      url,
      source: scriptCode,
      transformSourceMapURL: true,
    });
  }

  if (scriptCode.length === 0) {
    throw new Error('Only same domain scripts are allowed in sandboxed plugins');
  }

  sandboxEnv.evaluate(scriptCode);
}

export async function getPluginCode(meta: PluginMeta): Promise<string> {
  if (isHostedOnCDN(meta.module)) {
    // Load plugin from CDN, no need for "resolveWithCache" as CDN URLs already include the version
    const url = meta.module;
    const response = await fetch(url);
    let pluginCode = await response.text();
    pluginCode = transformPluginSourceForCDN({
      url,
      source: pluginCode,
      transformSourceMapURL: true,
    });
    return pluginCode;
  } else {
    // local plugin. resolveWithCache will append a query parameter with its version
    // to ensure correct cached version is served
    const pluginCodeUrl = resolveWithCache(meta.module);
    const response = await fetch(pluginCodeUrl);
    let pluginCode = await response.text();
    pluginCode = patchPluginSourceMap(meta, pluginCode);
    pluginCode = patchPluginAPIs(pluginCode);
    return pluginCode;
  }
}

function patchPluginAPIs(pluginCode: string): string {
  return pluginCode.replace(/window\.location/gi, 'window.locationSandbox');
}

/**
 * Patches the plugin's module.js source code references to sourcemaps to include the full url
 * of the module.js file instead of the regular relative reference.
 *
 * Because the plugin module.js code is loaded via fetch and then "eval" as a string
 * it can't find the references to the module.js.map directly and we need to patch it
 * to point to the correct location
 */
function patchPluginSourceMap(meta: PluginMeta, pluginCode: string): string {
  // skips inlined and files without source maps
  if (pluginCode.includes('//# sourceMappingURL=module.js.map')) {
    let replaceWith = '';
    // make sure we don't add the sourceURL twice
    if (!pluginCode.includes('//# sourceURL') || !pluginCode.includes('//@ sourceUrl')) {
      replaceWith += `//# sourceURL=module.js\n`;
    }
    // modify the source map url to point to the correct location
    const sourceCodeMapUrl = meta.module + '.map';
    replaceWith += `//# sourceMappingURL=${sourceCodeMapUrl}`;

    return pluginCode.replace('//# sourceMappingURL=module.js.map', replaceWith);
  }
  return pluginCode;
}