package de.pixart.messenger.generator;

import android.util.Base64;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Locale;
import java.util.TimeZone;

import de.pixart.messenger.Config;
import de.pixart.messenger.R;
import de.pixart.messenger.crypto.axolotl.AxolotlService;
import de.pixart.messenger.services.XmppConnectionService;
import de.pixart.messenger.utils.PhoneHelper;
import de.pixart.messenger.xmpp.jingle.stanzas.Content;

public abstract class AbstractGenerator {
    private final String[] FEATURES = {
            "urn:xmpp:jingle:1",
            Content.Version.FT_3.getNamespace(),
            Content.Version.FT_4.getNamespace(),
            "urn:xmpp:jingle:transports:s5b:1",
            "urn:xmpp:jingle:transports:ibb:1",
            "http://jabber.org/protocol/muc",
            "jabber:x:conference",
            "http://jabber.org/protocol/caps",
            "http://jabber.org/protocol/disco#info",
            "urn:xmpp:avatar:metadata+notify",
            "http://jabber.org/protocol/nick+notify",
            "urn:xmpp:ping",
            "jabber:iq:version",
            "http://jabber.org/protocol/chatstates"
    };
    private final String[] MESSAGE_CONFIRMATION_FEATURES = {
            "urn:xmpp:chat-markers:0",
            "urn:xmpp:receipts"
    };
    private final String[] MESSAGE_CORRECTION_FEATURES = {
            "urn:xmpp:message-correct:0"
    };
    private final String[] PRIVACY_SENSITIVE = {
            "urn:xmpp:time" //XEP-0202: Entity Time leaks time zone
    };
    private final String[] OTR = {
            "urn:xmpp:otr:0"
    };
    private String mVersion = null;

    private static final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", Locale.US);

    protected XmppConnectionService mXmppConnectionService;

    protected AbstractGenerator(XmppConnectionService service) {
        this.mXmppConnectionService = service;
    }

    protected String getIdentityVersion() {
        if (mVersion == null) {
            this.mVersion = PhoneHelper.getVersionName(mXmppConnectionService);
        }
        return this.mVersion;
    }

    public String getIdentityName() {
        return mXmppConnectionService.getString(R.string.app_name) + " " + getIdentityVersion();
    }

    public String getIdentityType() {
        if ("chromium".equals(android.os.Build.BRAND)) {
            return "pc";
        } else {
            return mXmppConnectionService.getString(R.string.default_resource).toLowerCase();
        }
    }

    public String getCapHash() {
        StringBuilder s = new StringBuilder();
        s.append("client/" + getIdentityType() + "//" + getIdentityName() + "<");
        MessageDigest md;
        try {
            md = MessageDigest.getInstance("SHA-1");
        } catch (NoSuchAlgorithmException e) {
            return null;
        }

        for (String feature : getFeatures()) {
            s.append(feature + "<");
        }
        byte[] sha1 = md.digest(s.toString().getBytes());
        return new String(Base64.encode(sha1, Base64.DEFAULT)).trim();
    }

    public static String getTimestamp(long time) {
        DATE_FORMAT.setTimeZone(TimeZone.getTimeZone("UTC"));
        return DATE_FORMAT.format(time);
    }

    public List<String> getFeatures() {
        ArrayList<String> features = new ArrayList<>();
        features.addAll(Arrays.asList(FEATURES));
        if (mXmppConnectionService.confirmMessages()) {
            features.addAll(Arrays.asList(MESSAGE_CONFIRMATION_FEATURES));
        }
        if (mXmppConnectionService.allowMessageCorrection()) {
            features.addAll(Arrays.asList(MESSAGE_CORRECTION_FEATURES));
        }
        if (Config.supportOmemo()) {
            features.add(AxolotlService.PEP_DEVICE_LIST_NOTIFY);
        }
        if (!mXmppConnectionService.useTorToConnect()) {
            features.addAll(Arrays.asList(PRIVACY_SENSITIVE));
        }
        if (Config.supportOtr()) {
            features.addAll(Arrays.asList(OTR));
        }
        Collections.sort(features);
        return features;
    }
}