import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.stream.Collectors;

public class DependencyDiscoverer {
    static ArrayList<String> dirs = new ArrayList<>();
    static ArrayList<String> files = new ArrayList<>();
    static ArrayList<String> parsedFiles = new ArrayList<>();

    static ConcurrentHashMap<String, ArrayList<String>> masterMap = new ConcurrentHashMap<>();

    public static void main(String[] args) {
        ConcurrentLinkedQueue<String> workQueue = new ConcurrentLinkedQueue<>();


        String cHome = System.getenv("CPATH");
        if (cHome != null) {
            Collections.addAll(dirs, cHome.split(":"));
            if (dirs.size() == 0) dirs.add(cHome);
        }
        dirs.add(".");
        Arrays.stream(args).forEach(arg -> {
            if (arg.startsWith("-I")) {
                dirs.add(arg.substring(2));
            } else {
                workQueue.add(arg);
            }
        });

        dirs.stream().filter(d -> Files.exists(Paths.get(d)))
                .forEach((String dir) -> files.addAll(Arrays.stream(new File(dir).listFiles())
                        .filter(f -> f.isFile() && f.getName().endsWith(".h")).map(File::getAbsolutePath).collect(Collectors.toList())));

        String i;
        while ((i = workQueue.poll()) != null) {
            ArrayList<String> dependencies = new ArrayList<>();
            String fileName = i.substring(i.lastIndexOf("/") + 1);
            String currentDirName = i.replace(fileName, "");
            dependencies.add(fileName);

            BufferedReader reader = null;

            try {
                File file = new File(i);
                reader = new BufferedReader(new FileReader(file));
                String line;
                while ((line = reader.readLine()) != null) {
                    line = line.trim();
                    if (line.startsWith("#include") && line.contains("\"")) {
                        String depFileName = line.substring(line.indexOf("\"") + 1, line.lastIndexOf("\""));
                        dependencies.add(depFileName);
                        String depPath = currentDirName + depFileName;
                        if (!parsedFiles.contains(depPath)) {
                            workQueue.add(depPath);
                            parsedFiles.add(depPath);
                        }
                    }
                }

            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            masterMap.put(fileName.endsWith(".h") ? fileName : fileName.substring(0, fileName.lastIndexOf(".")) + ".o", dependencies);
        }
//        masterMap.keySet().forEach(k -> {
//            System.out.println(k + ":" +  String.join(" ", masterMap.get(k)));
//        });

        masterMap.keySet().parallelStream().filter(k -> !k.endsWith(".h")).forEach(j -> {
            HashSet<String> output = new HashSet<>();
            output.addAll(getDependencies(new HashSet<>(), j));
            output.addAll(masterMap.get(j));
            System.out.println(j + ": " + String.join(" ", output));
        });


    }


    private static HashSet<String> getDependencies(HashSet<String> currentDeps, String initial) {
        if (masterMap.containsKey(initial)) {
            for (String k : masterMap.get(initial)) {
                if (!currentDeps.contains(k)) {
                    currentDeps.add(k);
                    if (masterMap.containsKey(k)) {
                        currentDeps.addAll(getDependencies(currentDeps, k));
                    }
                }
            }
        }
        return currentDeps;
    }

}