import * as http from 'node:http';
import * as os from 'node:os';

import { BaseOsImageBuilder } from './classes.baseosimagebuilder.js';
import type {
  IBaseOsImageJobRequest,
  IBaseOsImageJobResponse,
  ICoreBuildCapabilities,
} from './types.js';

export interface ICoreBuildServerOptions {
  port: number;
  token?: string;
  workdir: string;
  isoCreatorCommand: string;
  workerId: string;
}

export class CoreBuildServer {
  private server?: http.Server;
  private builder: BaseOsImageBuilder;

  public static fromEnv() {
    return new CoreBuildServer({
      port: Number(process.env.COREBUILD_PORT || '3060'),
      token: process.env.COREBUILD_TOKEN,
      workdir: process.env.COREBUILD_WORKDIR || BaseOsImageBuilder.getDefaultWorkdir(),
      isoCreatorCommand: process.env.ISO_CREATOR_COMMAND || 'isocreator',
      workerId: process.env.COREBUILD_WORKER_ID || BaseOsImageBuilder.getDefaultWorkerId(),
    });
  }

  constructor(private options: ICoreBuildServerOptions) {
    this.builder = new BaseOsImageBuilder({
      workdir: options.workdir,
      isoCreatorCommand: options.isoCreatorCommand,
    });
  }

  public async start() {
    this.server = http.createServer(async (req, res) => {
      await this.handleRequest(req, res).catch((error) => {
        this.sendJson(res, 500, {
          success: false,
          errorText: (error as Error).message,
        });
      });
    });
    await new Promise<void>((resolve) => this.server!.listen(this.options.port, resolve));
    console.log(`corebuild listening on ${this.options.port}`);
  }

  public async stop() {
    if (!this.server) {
      return;
    }
    await new Promise<void>((resolve, reject) => {
      this.server!.close((error) => error ? reject(error) : resolve());
    });
  }

  private async handleRequest(req: http.IncomingMessage, res: http.ServerResponse) {
    const url = new URL(req.url || '/', 'http://localhost');
    if (req.method === 'GET' && url.pathname === '/health') {
      this.sendJson(res, 200, { ok: true });
      return;
    }
    if (req.method === 'GET' && url.pathname === '/corebuild/v1/capabilities') {
      this.sendJson(res, 200, this.getCapabilities());
      return;
    }
    if (req.method === 'POST' && url.pathname === '/corebuild/v1/jobs/baseos-image') {
      const requestBody = await this.readJson<IBaseOsImageJobRequest>(req);
      this.validateToken(req, requestBody.apiToken);
      const response = await this.handleBaseOsImageJob(requestBody);
      this.sendJson(res, response.success ? 200 : 500, response);
      return;
    }
    this.sendJson(res, 404, { success: false, errorText: 'not found' });
  }

  private async handleBaseOsImageJob(
    requestArg: IBaseOsImageJobRequest,
  ): Promise<IBaseOsImageJobResponse> {
    const logs: string[] = [];
    try {
      const result = await this.builder.build(requestArg.job);
      return {
        success: true,
        artifact: result.artifact,
        logs: result.logs,
      };
    } catch (error) {
      logs.push((error as Error).message);
      return {
        success: false,
        logs,
        errorText: (error as Error).message,
      };
    }
  }

  private getCapabilities(): ICoreBuildCapabilities {
    return {
      workerId: this.options.workerId,
      supportedBuildTypes: ['baseos-image'],
      supportedArchitectures: ['amd64', 'arm64'],
      cpuCores: os.cpus().length,
      memoryGb: Math.round(os.totalmem() / 1024 / 1024 / 1024),
      workdir: this.options.workdir,
    };
  }

  private validateToken(reqArg: http.IncomingMessage, bodyTokenArg?: string) {
    if (!this.options.token) {
      return;
    }
    const authHeader = reqArg.headers.authorization;
    const headerToken = authHeader?.startsWith('Bearer ') ? authHeader.slice('Bearer '.length) : undefined;
    const token = bodyTokenArg || headerToken || reqArg.headers['x-corebuild-token'];
    if (token !== this.options.token) {
      throw new Error('corebuild token is invalid');
    }
  }

  private async readJson<T>(reqArg: http.IncomingMessage): Promise<T> {
    const chunks: Buffer[] = [];
    for await (const chunk of reqArg) {
      chunks.push(Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk));
    }
    const body = Buffer.concat(chunks).toString('utf8').trim();
    return body ? JSON.parse(body) as T : {} as T;
  }

  private sendJson(resArg: http.ServerResponse, statusCodeArg: number, bodyArg: object) {
    resArg.statusCode = statusCodeArg;
    resArg.setHeader('Content-Type', 'application/json');
    resArg.end(JSON.stringify(bodyArg));
  }
}