import * as interfaces from './interfaces.js';
import * as plugins from './plugins.js';
import * as paths from './paths.js';
import * as ntml from './ntml/index.js';

export interface IPublicServerOptions {
  packageBaseDirectory?: string;
  npmRegistryUrl?: string;
  allowedPackages?: string[];
  port?: number;
  mode: 'dev' | 'prod';
  log?: boolean;
}

/**
 * the main public server instance
 */
export class UiPublicServer {
  public projectinfo = new plugins.projectinfo.ProjectinfoNpm(paths.packageDir);
  public readme: string;
  public startedAt: string;
  private server: plugins.http.Server;
  private npmRegistry: plugins.smartnpm.NpmRegistry;

  private corsDev = '*';
  private corsProd = ''; // TODO: Define allowed URLs

  public defaultOptions: IPublicServerOptions = {
    packageBaseDirectory: './',
    npmRegistryUrl: 'https://registry.npmjs.org',
    allowedPackages: [],
    port: 8080,
    mode: 'dev',
    log: true,
  };
  public options: IPublicServerOptions;

  constructor(optionsArg?: IPublicServerOptions) {
    // lets create an npm instance for the registry that we are talking to
    this.options = {
      ...this.defaultOptions,
      ...optionsArg,
    };

    if (!this.options.packageBaseDirectory.endsWith('/')) {
      this.options.packageBaseDirectory += '/';
    }

    this.npmRegistry = new plugins.smartnpm.NpmRegistry({
      npmRegistryUrl: this.options.npmRegistryUrl,
    });
  }

  /**
   * initializes the readme content
   */
  private async initReadme(): Promise<void> {
    const readmePath = plugins.path.join(paths.packageDir, 'readme.md');
    const readmeContent = await plugins.smartfile.fs.toStringSync(readmePath);
    this.readme = await plugins.smartmarkdown.SmartMarkdown.easyMarkdownToHtml(readmeContent);
  }

  /**
   * starts the server
   */
  public async startServer() {
    console.log('starting the uipublicserver');

    // Initialize readme
    await this.initReadme();

    const done = plugins.smartpromise.defer();
    const expressApplication = plugins.express();

    const shouldCompress = (req: plugins.express.Request, res: plugins.express.Response) => {
      if (req.headers['x-no-compression']) {
        // don't compress responses with this request header
        return false;
      }

      // fallback to standard filter function
      return plugins.compression.filter(req, res);
    };

    expressApplication.use(plugins.compression({ filter: shouldCompress }));

    if (this.options.mode === 'dev') {
      expressApplication.use('/peek/', async (req, res) => {
        const host = req.headers.host || 'localhost';
        const parsedUrl = new plugins.url.URL(`http://${host}${req.url}`);
        const simpleResponse: interfaces.ISimpleResponse = await this.renderPeek({
          headers: req.headers,
          parsedUrl,
        });
        for (const header of Object.keys(simpleResponse.headers)) {
          res.setHeader(header, simpleResponse.headers[header]);
        }
        res.status(simpleResponse.status);
        res.write(simpleResponse.body);
        res.end();
      });

      expressApplication.use('/readme/', async (req, res) => {
        const host = req.headers.host || 'localhost';
        const parsedUrl = new plugins.url.URL(`http://${host}${req.url}`);
        const simpleResponse: interfaces.ISimpleResponse = await this.renderReadme({
          headers: req.headers,
          parsedUrl,
        });
        for (const header of Object.keys(simpleResponse.headers)) {
          res.setHeader(header, simpleResponse.headers[header]);
        }
        res.status(simpleResponse.status);
        res.write(simpleResponse.body);
        res.end();
      });
    }

    expressApplication.use('/', async (req, res) => {
      const host = req.headers.host || 'localhost';
      const parsedUrl = new plugins.url.URL(`http://${host}${req.url}`);
      const simpleResponse: interfaces.ISimpleResponse = await this.render({
        headers: req.headers,
        parsedUrl,
      });
      for (const header of Object.keys(simpleResponse.headers)) {
        res.setHeader(header, simpleResponse.headers[header]);
      }
      // CORS
      res.setHeader('ui-public-server-version', this.projectinfo.version);
      res.setHeader('access-control-allow-origin', true ? this.corsDev : this.corsProd); // TODO: replace true with check for env
      res.status(simpleResponse.status);
      res.write(simpleResponse.body);
      res.end();
    });

    // note: We assume that ssl termination is done in reverse proxy in kubernetes. so simple http should suffice here.
    this.server = expressApplication.listen(this.options.port, () => {
      console.log(`listening on port ${this.options.port}`);
      this.startedAt = new Date().toISOString();
      done.resolve();
    });
    await done.promise;
  }

  public disableLogging() {
    this.options.log = false;
  }

  /**
   * stops the server
   */
  public async stopServer() {
    const done = plugins.smartpromise.defer();
    if (!this.server) {
      console.log('server does not seem to be started, so no need to stop it');
      return;
    }
    this.server.close(() => {
      done.resolve();
    });
    await done.promise;
  }

  public requestMap: { [key: string]: plugins.smartpromise.Deferred<any> } = {};

  /**
   * renders a response using interfaces.ISimpleRequest and interfaces.ISimpleResponse
   * @param req
   */
  private render: interfaces.IRenderFunction = async (req) => {
    const pathArray = req.parsedUrl.pathname.split('/');

    if (pathArray.length < 3) {
      const textArray = [
        `serving javascript to the web for Lossless GmbH.<br/>`,
        `Running in mode: <b>${this.options.mode}</b><br/><br/>`,
      ];
      if (this.options.mode === 'dev') {
        textArray.push(
          `<b>Wondering what we serve?</b> <a href="/peek/">Lets take a peek!</a><br/>`
        );
        textArray.push(`<b>Documentation:</b> <a href="/readme/">Read the docs</a>`);
      }
      return {
        headers: {
          'content-type': 'text/html',
        },
        status: 201,
        body: await plugins.litNtml.html`
        ${ntml.getBody(this, textArray)}
      `,
      };
    }

    // lets care about the npm organization
    const npmOrg = pathArray[1];
    if (!npmOrg.startsWith('@')) {
      console.log('malformed npmorg');
      return {
        status: 500,
        headers: {
          'content-type': 'text/html',
        },
        body: `npmorg "${npmOrg}" must start with @`,
      };
    }

    // lets care about the packageName
    const npmPackage = pathArray[2];
    const packageName = `${npmOrg}/${npmPackage}`;
    if (this.options.log) {
      console.log(
        `got a request for package ${packageName} on registry ${this.npmRegistry.options.npmRegistryUrl}`
      );
    }
    if (!this.options.allowedPackages.includes(packageName)) {
      return {
        headers: {
          'content-type': 'text/html',
        },
        status: 503,
        body: await plugins.litNtml.html`
        the requested package is not allowlisted for public access
      `,
      };
    }

    // lets care about the inner package path
    let filePath = this.options.packageBaseDirectory;
    let first = true;
    for (let i = 3; i < pathArray.length; i++) {
      if (first) {
        filePath += './';
        first = false;
      } else {
        filePath += '/';
      }
      filePath += pathArray[i];
    }

    // lets care about version and disttag

    const version = req.parsedUrl.searchParams.get('version') || '';
    const distTag = req.parsedUrl.searchParams.get('disttag') || '';

    const requestDescriptor = `${packageName}/${filePath}/${distTag}/${version}`;

    let smartfile: plugins.smartfile.SmartFile;

    // protect against parallel requests
    if (this.requestMap[requestDescriptor]) {
      smartfile = await this.requestMap[requestDescriptor].promise;
    } else {
      this.requestMap[requestDescriptor] = plugins.smartpromise.defer();
      smartfile = await this.npmRegistry
        .getFileFromPackage(packageName, filePath, {
          version,
          distTag,
        })
        .catch((err) => {
          console.log(err);
          return null;
        });
      this.requestMap[requestDescriptor].resolve(smartfile);
      delete this.requestMap[requestDescriptor];
    }

    if (!smartfile) {
      return {
        status: 404,
        headers: {
          'content-type': 'text/html',
        },
        body: await ntml.getBody(
          this,
          `${packageName}@${version} does not have a file at "${filePath}"`
        ),
      };
    }

    // Detect mime type from buffer
    const mimeResult = await plugins.smartmime.detectMimeType({ buffer: smartfile.contentBuffer });
    const contentType = mimeResult?.mime || 'application/octet-stream';

    return {
      headers: {
        'cache-control': `max-age=${
          (version
            ? plugins.smarttime.getMilliSecondsFromUnits({ months: 1 })
            : plugins.smarttime.getMilliSecondsFromUnits({ days: 1 })) / 1000
        }`,
        'content-length': smartfile.contentBuffer.length.toString(),
        'content-type': contentType,
      },
      status: 200,
      body: smartfile.contentBuffer,
    };
  };

  private renderPeek: interfaces.IRenderFunction = async (req) => {
    const pathArray = req.parsedUrl.pathname.split('/');
    const npmOrg = pathArray[1];
    const npmPackage = pathArray[2];
    const npmPackageName = `${npmOrg}/${npmPackage}`;
    const distTag = req.parsedUrl.searchParams.get('disttag');
    const version = req.parsedUrl.searchParams.get('version');

    // lets care about cors

    if (!npmOrg || !npmPackage || !this.options.allowedPackages.includes(npmPackageName)) {
      return {
        status: 200,
        headers: {
          'content-type': 'text/html',
        },
        body: `
          ${await ntml.getBody(this, [
            `<a href="../">../ -> Go back</a><br/>`,
            `<b>allowlisted packages:</b><br/>`,
            ...this.options.allowedPackages.map((packageArg) => {
              return `
              <div>"${packageArg}" -> mapping to "${this.options.packageBaseDirectory}" inside the package <a href="/peek/${packageArg}">Peek...</a></div>
            `;
            }),
          ])}
        `,
      };
    }
    const result = await this.npmRegistry
      .getFilesFromPackage(npmPackageName, plugins.path.join(this.options.packageBaseDirectory), {
        version: version,
        distTag: distTag,
      })
      .catch((err) => {
        return;
      });

    if (!result) {
      return {
        status: 404,
        headers: {
          'content-type': 'text/html',
        },
        body: `
          ${await ntml.getBody(this, [
            `<a href="/peek/">/peek/ -> Go to peek overview</a><br/>`,
            `<b>Not found: package ${npmPackageName}@${
              version || 'latest'
            } is not available on the supplied registry</b><br/>`,
          ])}
        `,
      };
    }

    const packageInfo = await this.npmRegistry.getPackageInfo(npmPackageName);

    return {
      status: 200,
      headers: {
        'content-type': 'text/html',
      },
      body: `
        ${await ntml.getBody(this, [
          `<a href="/peek/">/peek/ -> Go to peek overview</a><br/><br/>`,
          `<h1>${npmPackageName}@${version || distTag || '<i>inferred</i> latest'}</h1>`,
          `<b>Versions:</b> ${packageInfo.allVersions
            .map(
              (versionArg) =>
                `<a href="./${npmPackage}?version=${versionArg.version}">${versionArg.version}</a> | `
            )
            .join('')}<br/><br/>`,
          `<b>DistTags:</b> ${
            packageInfo.allDistTags
              .map(
                (distTagArg) =>
                  `<a href="./${npmPackage}?disttag=${distTagArg.name}">${distTagArg.name} (${distTagArg.targetVersion})</a> | `
              )
              .join('') || 'no dist tags found!'
          }<br/><br/>`,
          `<b>File Overview at version and path:</b><br/>`,
          `"<b>${npmPackageName}@${
            version || distTag || '<i>inferred</i> latest'
          }</b>" under internal path "<b>${this.options.packageBaseDirectory}</b>"<br/></br>`,
          ...result.map((smartfile) => {
            const displayPath = smartfile.path.replace(
              plugins.path.join('package', this.options.packageBaseDirectory),
              ''
            );
            return `<a href="/${npmPackageName}/${displayPath}?version=${version || ''}&disttag=${
              distTag || ''
            }">${displayPath}</a><br/>`;
          }),
        ])}
      `,
    };
  };

  private renderReadme: interfaces.IRenderFunction = async (req) => {
    return {
      status: 200,
      headers: {
        'content-type': 'text/html',
      },
      body: await ntml.getBody(this, [
        `<style>
          pre {
            display: block;
            background: #fafafa;
            border: 1px dotted #CCC;
            padding: 20px;
          }
        </style>`,
        this.readme,
      ]),
    };
  };
}