package de.mlessmann.certassist.service;

import de.mlessmann.certassist.except.UnresolvableCLIDependency;
import java.io.File;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.List;
import java.util.Objects;
import java.util.Optional;
import java.util.concurrent.atomic.AtomicBoolean;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.SystemUtils;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Service;

@Service
@Slf4j
public class ExecutableResolver {

    private static final AtomicBoolean loggedPath = new AtomicBoolean(false);

    @Value("${openssl.path:#{null}}")
    private String opensslPath;

    public String getOpenSSLPath() throws UnresolvableCLIDependency {
        if (opensslPath == null) {
            log.atDebug().log("No openssl path configured, falling back to resolving by shell.");
            var optSSLPath = searchCommandFromPath("openssl");
            opensslPath = optSSLPath.orElseThrow(() -> new UnresolvableCLIDependency("openssl", "openssl.path"));
        }

        Path configuredPath = new File(opensslPath).toPath();
        if (!Files.isRegularFile(configuredPath)) {
            throw new UnresolvableCLIDependency("openssl", "openssl.path");
        }

        return opensslPath;
    }

    private Optional<String> searchCommandFromPath(String executableName) {
        String envPath = System.getenv("PATH");
        Objects.requireNonNull(envPath, "Environment variable 'PATH' is not set?!");
        String[] pathEntries = envPath.split(File.pathSeparator);

        if (!loggedPath.get()) {
            loggedPath.set(true);
            for (String pathEntry : pathEntries) {
                log.atError().log("Path entry: {}", pathEntry);
            }
        }

        for (String pathEntry : pathEntries) {
            for (String fileExtension : getAllowedExtensions()) {
                Path executablePath = Path.of(pathEntry, executableName + fileExtension);
                if (Files.isRegularFile(executablePath) && Files.isExecutable(executablePath)) {
                    return Optional.of(executablePath.toString());
                }
            }
        }

        log.error(
            "Could not find executable '{}' in PATH. Make sure that it exists on the of the directory and is executable.",
            executableName
        );
        return Optional.empty();
    }

    public List<String> getAllowedExtensions() {
        if (SystemUtils.IS_OS_WINDOWS) {
            return List.of(".exe", ".bat", ".cmd");
        } else {
            return List.of("", ".sh");
        }
    }
}