package eu.siacs.conversations.entities;

import android.content.ContentValues;
import android.database.Cursor;
import android.util.Base64;
import com.google.common.base.Strings;
import eu.siacs.conversations.xml.Element;
import eu.siacs.conversations.xml.Namespace;
import eu.siacs.conversations.xmpp.forms.Data;
import eu.siacs.conversations.xmpp.forms.Field;
import im.conversations.android.xmpp.model.stanza.Iq;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

public class ServiceDiscoveryResult {
    public static final String TABLENAME = "discovery_results";
    public static final String HASH = "hash";
    public static final String VER = "ver";
    public static final String RESULT = "result";
    protected final String hash;
    protected final byte[] ver;
    protected final List<String> features;
    protected final List<Data> forms;
    private final List<Identity> identities;

    public ServiceDiscoveryResult(final Iq packet) {
        this.identities = new ArrayList<>();
        this.features = new ArrayList<>();
        this.forms = new ArrayList<>();
        this.hash = "sha-1"; // We only support sha-1 for now

        final List<Element> elements = packet.query().getChildren();

        for (final Element element : elements) {
            if (element.getName().equals("identity")) {
                Identity id = new Identity(element);
                if (id.getType() != null && id.getCategory() != null) {
                    identities.add(id);
                }
            } else if (element.getName().equals("feature")) {
                if (element.getAttribute("var") != null) {
                    features.add(element.getAttribute("var"));
                }
            } else if (element.getName().equals("x")
                    && element.getAttribute("xmlns").equals(Namespace.DATA)) {
                forms.add(Data.parse(element));
            }
        }
        this.ver = this.mkCapHash();
    }

    private ServiceDiscoveryResult(String hash, byte[] ver, JSONObject o) throws JSONException {
        this.identities = new ArrayList<>();
        this.features = new ArrayList<>();
        this.forms = new ArrayList<>();
        this.hash = hash;
        this.ver = ver;

        JSONArray identities = o.optJSONArray("identities");
        if (identities != null) {
            for (int i = 0; i < identities.length(); i++) {
                this.identities.add(new Identity(identities.getJSONObject(i)));
            }
        }
        JSONArray features = o.optJSONArray("features");
        if (features != null) {
            for (int i = 0; i < features.length(); i++) {
                this.features.add(features.getString(i));
            }
        }
        JSONArray forms = o.optJSONArray("forms");
        if (forms != null) {
            for (int i = 0; i < forms.length(); i++) {
                this.forms.add(createFormFromJSONObject(forms.getJSONObject(i)));
            }
        }
    }

    private ServiceDiscoveryResult() {
        this.hash = "sha-1";
        this.features = Collections.emptyList();
        this.identities = Collections.emptyList();
        this.ver = null;
        this.forms = Collections.emptyList();
    }

    public static ServiceDiscoveryResult empty() {
        return new ServiceDiscoveryResult();
    }

    public ServiceDiscoveryResult(Cursor cursor) throws JSONException {
        this(
                cursor.getString(cursor.getColumnIndexOrThrow(HASH)),
                Base64.decode(cursor.getString(cursor.getColumnIndexOrThrow(VER)), Base64.DEFAULT),
                new JSONObject(cursor.getString(cursor.getColumnIndexOrThrow(RESULT))));
    }

    private static String clean(String s) {
        return s.replace("<", "&lt;");
    }

    private static String blankNull(String s) {
        return s == null ? "" : clean(s);
    }

    private static Data createFormFromJSONObject(JSONObject o) {
        Data data = new Data();
        JSONArray names = o.names();
        for (int i = 0; i < names.length(); ++i) {
            try {
                String name = names.getString(i);
                JSONArray jsonValues = o.getJSONArray(name);
                ArrayList<String> values = new ArrayList<>(jsonValues.length());
                for (int j = 0; j < jsonValues.length(); ++j) {
                    values.add(jsonValues.getString(j));
                }
                data.put(name, values);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return data;
    }

    private static JSONObject createJSONFromForm(Data data) {
        JSONObject object = new JSONObject();
        for (Field field : data.getFields()) {
            try {
                JSONArray jsonValues = new JSONArray();
                for (String value : field.getValues()) {
                    jsonValues.put(value);
                }
                object.put(field.getFieldName(), jsonValues);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        try {
            JSONArray jsonValues = new JSONArray();
            jsonValues.put(data.getFormType());
            object.put(Data.FORM_TYPE, jsonValues);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return object;
    }

    public Identity getIdentity(String category, String type) {
        for (Identity id : this.getIdentities()) {
            if ((category == null || id.getCategory().equals(category)) &&
                    (type == null || id.getType().equals(type))) {
                return id;
            }
        }

        return null;
    }

    public boolean hasIdentity(String category, String type) {
        return getIdentity(category, type) != null;
    }

    public String getVer() {
        return Base64.encodeToString(this.ver, Base64.NO_WRAP);
    }

    public List<Identity> getIdentities() {
        return this.identities;
    }

    public List<String> getFeatures() {
        return this.features;
    }

    public String getExtendedDiscoInformation(final String formType, final String name) {
        for (final Data form : this.forms) {
            if (formType.equals(form.getFormType())) {
                for (final Field field : form.getFields()) {
                    if (name.equals(field.getFieldName())) {
                        return field.getValue();
                    }
                }
            }
        }
        return null;
    }

    private byte[] mkCapHash() {
        StringBuilder s = new StringBuilder();

        List<Identity> identities = this.getIdentities();
        Collections.sort(identities);

        for (Identity id : identities) {
            s.append(blankNull(id.getCategory()))
                    .append("/")
                    .append(blankNull(id.getType()))
                    .append("/")
                    .append(blankNull(id.getLang()))
                    .append("/")
                    .append(blankNull(id.getName()))
                    .append("<");
        }

        final List<String> features = this.getFeatures();
        Collections.sort(features);
        for (final String feature : features) {
            s.append(clean(feature)).append("<");
        }

        Collections.sort(forms, Comparator.comparing(Data::getFormType));
        for (final Data form : forms) {
            s.append(clean(form.getFormType())).append("<");
            final List<Field> fields = form.getFields();
            Collections.sort(
                    fields, Comparator.comparing(lhs -> Strings.nullToEmpty(lhs.getFieldName())));
            for (final Field field : fields) {
                s.append(Strings.nullToEmpty(field.getFieldName())).append("<");
                final List<String> values = field.getValues();
                Collections.sort(values, Comparator.comparing(ServiceDiscoveryResult::blankNull));
                for (final String value : values) {
                    s.append(blankNull(value)).append("<");
                }
            }
        }

        MessageDigest md;
        try {
            md = MessageDigest.getInstance("SHA-1");
        } catch (NoSuchAlgorithmException e) {
            return null;
        }

        return md.digest(s.toString().getBytes(StandardCharsets.UTF_8));
    }

    private JSONObject toJSON() {
        try {
            JSONObject o = new JSONObject();

            JSONArray ids = new JSONArray();
            for (Identity id : this.getIdentities()) {
                ids.put(id.toJSON());
            }
            o.put("identities", ids);

            o.put("features", new JSONArray(this.getFeatures()));

            JSONArray forms = new JSONArray();
            for (Data data : this.forms) {
                forms.put(createJSONFromForm(data));
            }
            o.put("forms", forms);

            return o;
        } catch (JSONException e) {
            return null;
        }
    }

    public ContentValues getContentValues() {
        final ContentValues values = new ContentValues();
        values.put(HASH, this.hash);
        values.put(VER, getVer());
        JSONObject jsonObject = toJSON();
        values.put(RESULT, jsonObject == null ? "" : jsonObject.toString());
        return values;
    }

    public static class Identity implements Comparable<Identity> {
        protected final String type;
        protected final String lang;
        protected final String name;
        final String category;

        Identity(final String category, final String type, final String lang, final String name) {
            this.category = category;
            this.type = type;
            this.lang = lang;
            this.name = name;
        }

        Identity(final Element el) {
            this(
                    el.getAttribute("category"),
                    el.getAttribute("type"),
                    el.getAttribute("xml:lang"),
                    el.getAttribute("name"));
        }

        Identity(final JSONObject o) {

            this(
                    o.optString("category", null),
                    o.optString("type", null),
                    o.optString("lang", null),
                    o.optString("name", null));
        }

        public String getCategory() {
            return this.category;
        }

        public String getType() {
            return this.type;
        }

        public String getLang() {
            return this.lang;
        }

        public String getName() {
            return this.name;
        }

        JSONObject toJSON() {
            try {
                JSONObject o = new JSONObject();
                o.put("category", this.getCategory());
                o.put("type", this.getType());
                o.put("lang", this.getLang());
                o.put("name", this.getName());
                return o;
            } catch (JSONException e) {
                return null;
            }
        }

        @Override
        public int compareTo(final Identity o) {
            int r = blankNull(this.getCategory()).compareTo(blankNull(o.getCategory()));
            if (r == 0) {
                r = blankNull(this.getType()).compareTo(blankNull(o.getType()));
            }
            if (r == 0) {
                r = blankNull(this.getLang()).compareTo(blankNull(o.getLang()));
            }
            if (r == 0) {
                r = blankNull(this.getName()).compareTo(blankNull(o.getName()));
            }

            return r;
        }
    }
}