package io.gitlab.jfronny.commons.serialize.databind.impl.adapter;

import io.gitlab.jfronny.commons.serialize.databind.api.SerializerFor;
import io.gitlab.jfronny.commons.serialize.databind.api.TypeAdapter;
import io.gitlab.jfronny.commons.serialize.ISO8601Utils;
import io.gitlab.jfronny.commons.serialize.databind.impl.PreJava9DateFormatProvider;
import io.gitlab.jfronny.commons.serialize.MalformedDataException;
import io.gitlab.jfronny.commons.serialize.SerializeReader;
import io.gitlab.jfronny.commons.serialize.SerializeWriter;

import java.text.DateFormat;
import java.text.ParseException;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.*;

@SerializerFor(targets = Date.class)
public class DefaultDateTypeAdapter extends TypeAdapter<Date> {
    private static final String SIMPLE_NAME = "DefaultDateTypeAdapter";

    /**
     * List of 1 or more different date formats used for de-serialization attempts. The first of them
     * is used for serialization as well.
     */
    private final List<DateFormat> dateFormats = new ArrayList<>();

    public DefaultDateTypeAdapter() {
        dateFormats.add(DateFormat.getDateTimeInstance(DateFormat.DEFAULT, DateFormat.DEFAULT, Locale.US));
        if (!Locale.getDefault().equals(Locale.US)) {
            dateFormats.add(DateFormat.getDateTimeInstance(DateFormat.DEFAULT, DateFormat.DEFAULT));
        }
        dateFormats.add(PreJava9DateFormatProvider.getUsDateTimeFormat(DateFormat.DEFAULT, DateFormat.DEFAULT));
    }

    @Override
    public <TEx extends Exception, Writer extends SerializeWriter<TEx, Writer>> void serialize(Date value, Writer writer) throws TEx, MalformedDataException {
        DateFormat dateFormat = dateFormats.getFirst();
        String dateFormatAsString;
        // Needs to be synchronized since JDK DateFormat classes are not thread-safe
        synchronized (dateFormats) {
            dateFormatAsString = dateFormat.format(value);
        }
        writer.value(dateFormatAsString);

    }

    @Override
    public <TEx extends Exception, Reader extends SerializeReader<TEx, Reader>> Date deserialize(Reader reader) throws TEx, MalformedDataException {
        String s = reader.nextString();
        // Needs to be synchronized since JDK DateFormat classes are not thread-safe
        synchronized (dateFormats) {
            for (DateFormat dateFormat : dateFormats) {
                TimeZone originalTimeZone = dateFormat.getTimeZone();
                try {
                    return dateFormat.parse(s);
                } catch (ParseException ignored) {
                    // OK: try the next format
                } finally {
                    dateFormat.setTimeZone(originalTimeZone);
                }
            }
        }

        try {
            return ISO8601Utils.parse(s, new ParsePosition(0));
        } catch (ParseException e) {
            throw new MalformedDataException(
                    "Failed parsing '" + s + "' as Date; at path " + reader.getPreviousPath(), e);
        }
    }

    @Override
    public String toString() {
        DateFormat defaultFormat = dateFormats.getFirst();
        if (defaultFormat instanceof SimpleDateFormat) {
            return SIMPLE_NAME + '(' + ((SimpleDateFormat) defaultFormat).toPattern() + ')';
        } else {
            return SIMPLE_NAME + '(' + defaultFormat.getClass().getSimpleName() + ')';
        }
    }
}