package com.redhat.training;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.security.KeyManagementException;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.util.Optional;

import javax.net.ssl.SSLContext;

import org.apache.http.ssl.SSLContextBuilder;
import org.apache.http.ssl.SSLContexts;
import org.eclipse.microprofile.config.inject.ConfigProperty;
import org.eclipse.microprofile.rest.client.RestClientBuilder;
import org.jboss.logging.Logger;

import jakarta.annotation.PostConstruct;
import jakarta.enterprise.context.ApplicationScoped;
import jakarta.ws.rs.POST;
import jakarta.ws.rs.Path;

@ApplicationScoped
@Path("/jobs")
public class Activator {
    final Logger LOG = Logger.getLogger(Activator.class.getName());

    @ConfigProperty(name = "api.token")
    Optional<String> token;

    @ConfigProperty(name = "api.endpoint")
    Optional<String> apiserver;

    @ConfigProperty(name = "api.tlsca.file")
    Optional<String> tlsca;

    ApiClient k8s;

    @PostConstruct
    public void checkEnv() {
        // Check for API token.
        if (token.isPresent() && !token.get().isEmpty()) {
            LOG.debug("Got API token from environment.");
        } else {
            LOG.warn("API token not found in environment. Trying service account.");
            File tf = new File("/var/run/secrets/kubernetes.io/serviceaccount/token");
            if (tf.exists()) {
                try {
                    BufferedReader br = new BufferedReader(new FileReader(tf));
                    this.token = Optional.of(br.readLine());
                    br.close();
                } catch (IOException ioe) {
                    throw new RuntimeException("Can not load service account token: " + ioe.getMessage(), ioe);
                }
            } else {
                throw new RuntimeException("API token unobtainable. Can not talk to API.");
            }
        }

        // Check for API server.
        if (apiserver.isPresent() && !apiserver.get().isEmpty()) {
            LOG.debug("Got API server endpoint from environment.");
        } else {
            LOG.warn("API server endpoint not set, defaulting to internal API server.");
            apiserver = Optional.of("https://kubernetes.default/");
        }

        // Check for TLS CA cert.
        SSLContext sc = null;
        if (apiserver.get().startsWith("https://")) {
            File tlscaFile;
            if (tlsca.isPresent() && !tlsca.get().isEmpty()) {
                LOG.debug("Got TLS CA cert file from environment, checking.");
                tlscaFile = new File(tlsca.get());
            } else {
                LOG.warn("TLS CA cert not found in environment. Trying service account.");
                tlscaFile = new File("/var/run/secrets/kubernetes.io/serviceaccount/ca.crt");
            }
            if (!tlscaFile.exists()) {
                throw new RuntimeException("TLS CA cert file set, but does not exist.");
            }
            LOG.info("Attempting to build SSLContext with " + tlscaFile.getAbsolutePath());
            try {
                SSLContextBuilder scb = SSLContexts.custom().loadTrustMaterial(tlscaFile);
                sc = scb.build();
            } catch (NoSuchAlgorithmException | KeyStoreException | CertificateException | IOException | KeyManagementException e) {
                throw new RuntimeException("Could not load TLS CA: " + e.getMessage(), e);
            }
        }

        try {
            if (sc == null) {
                this.k8s = RestClientBuilder.newBuilder()
                                            .baseUri(new URI(this.apiserver.get()))
                                            .build(ApiClient.class);
            } else {
                this.k8s = RestClientBuilder.newBuilder()
                                            .baseUri(new URI(this.apiserver.get()))
                                            .sslContext(sc)
                                            .build(ApiClient.class);
            }
        } catch (URISyntaxException use) {
            throw new RuntimeException("Could not construct BASE URI for REST client: " + use.getMessage(), use);
        }
    }

    @POST
    public String createJob(JobDescription job) {
        return k8s.createJob("Bearer " + token.get(),
                            job.getNamespace(),
                            job.getName(),
                            new Job(job.getNamespace(),
                                     job.getName(),
                                     job.getCommand()).getApiResource());
    }
}