package io.trygvis.rules.acme;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
import com.fasterxml.jackson.dataformat.yaml.YAMLGenerator;
import org.drools.core.common.DefaultFactHandle;
import org.kie.api.runtime.rule.FactHandle;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.AbstractMap;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;

public class AcmeIo {
    private final ObjectMapper mapper;

    public AcmeIo() {
        var factory = new YAMLFactory();
        factory.enable(YAMLGenerator.Feature.USE_NATIVE_TYPE_ID);
        factory.enable(YAMLGenerator.Feature.USE_NATIVE_OBJECT_ID);
        mapper = new ObjectMapper(factory);
        mapper.findAndRegisterModules();
    }

    public List<Object> load(String file) throws IOException {
        var parser = mapper.getFactory().createParser(new File(file));

        var objects = mapper.readValues(parser, AcmeObject.class).readAll(new ArrayList<>());

        List<Object> items = new ArrayList<>(objects.size());
        for (AcmeObject object : objects) {
            try {
                var type = Class.forName(object.type);
                var x = mapper.treeToValue(object.data, type);
                items.add(x);
            } catch (ClassNotFoundException e) {
                throw new IOException(e);
            }
        }

        return items;
    }

    public void dump(String s, Collection<FactHandle> factHandles) throws IOException {
        var out = new File("out");

        if (!out.isDirectory()) {
            if (!out.mkdirs()) {
                throw new IOException("Could not create directory: " + out);
            }
        }

        List<Map.Entry<String, Object>> facts = new ArrayList<>(factHandles.size());
        for (var handle : factHandles) {
            if (handle instanceof DefaultFactHandle h) {
                facts.add(new AbstractMap.SimpleImmutableEntry<>(
                        h.getObjectClassName(),
                        h.getObject()));
            }
        }

        facts.sort(Map.Entry.comparingByKey());

        var factory = mapper.getFactory();
        try (var writer = new FileWriter(new File(out, s + ".yaml"));
             var g = factory.createGenerator(writer)) {
            for (Map.Entry<String, Object> fact : facts) {
                g.writeObject(new AcmeObject(
                        fact.getKey(),
                        mapper.valueToTree(fact.getValue())
                ));
            }
        }
    }
}