/*
 * Copyright (C) 2018 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.telephony;

import static android.text.TextUtils.formatSimple;

import android.annotation.IntRange;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.os.Parcel;
import android.telephony.AccessNetworkConstants.NgranBands.NgranBand;
import android.telephony.gsm.GsmCellLocation;
import android.util.ArraySet;

import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Objects;
import java.util.Set;

/**
 * Information to represent a unique NR(New Radio 5G) cell.
 */
public final class CellIdentityNr extends CellIdentity {
    private static final String TAG = "CellIdentityNr";

    private static final int MAX_PCI = 1007;
    private static final int MAX_TAC = 16777215; // 0xffffff
    private static final int MAX_NRARFCN = 3279165;
    private static final long MAX_NCI = 68719476735L;

    private final int mNrArfcn;
    private final int mPci;
    private final int mTac;
    private final long mNci;
    private final int[] mBands;

    // a list of additional PLMN-IDs reported for this cell
    private final ArraySet<String> mAdditionalPlmns;

    /** @hide */
    public CellIdentityNr() {
        super(TAG, CellInfo.TYPE_NR, null, null, null, null);
        mNrArfcn = CellInfo.UNAVAILABLE;
        mPci = CellInfo.UNAVAILABLE;
        mTac = CellInfo.UNAVAILABLE;
        mNci = CellInfo.UNAVAILABLE;
        mBands = new int[] {};
        mAdditionalPlmns = new ArraySet();
        mGlobalCellId = null;
    }

    /**
     * @param pci Physical Cell Id in range [0, 1007].
     * @param tac 24-bit Tracking Area Code.
     * @param nrArfcn NR Absolute Radio Frequency Channel Number, in range [0, 3279165].
     * @param bands Bands used by the cell. Band number defined in 3GPP TS 38.101-1 and TS 38.101-2.
     * @param mccStr 3-digit Mobile Country Code in string format.
     * @param mncStr 2 or 3-digit Mobile Network Code in string format.
     * @param nci The 36-bit NR Cell Identity in range [0, 68719476735].
     * @param alphal long alpha Operator Name String or Enhanced Operator Name String.
     * @param alphas short alpha Operator Name String or Enhanced Operator Name String.
     * @param additionalPlmns a list of additional PLMN IDs broadcast by the cell
     *
     * @hide
     */
    public CellIdentityNr(int pci, int tac, int nrArfcn, @NonNull @NgranBand int[] bands,
                          @Nullable String mccStr, @Nullable String mncStr, long nci,
                          @Nullable String alphal, @Nullable String alphas,
                          @NonNull Collection<String> additionalPlmns) {
        super(TAG, CellInfo.TYPE_NR, mccStr, mncStr, alphal, alphas);
        mPci = inRangeOrUnavailable(pci, 0, MAX_PCI);
        mTac = inRangeOrUnavailable(tac, 0, MAX_TAC);
        mNrArfcn = inRangeOrUnavailable(nrArfcn, 0, MAX_NRARFCN);
        // TODO: input validation for bands
        mBands = bands;
        mNci = inRangeOrUnavailable(nci, 0, MAX_NCI);
        mAdditionalPlmns = new ArraySet<>(additionalPlmns.size());
        for (String plmn : additionalPlmns) {
            if (isValidPlmn(plmn)) {
                mAdditionalPlmns.add(plmn);
            }
        }
        updateGlobalCellId();
    }

    /** @hide */
    @Override
    public @NonNull CellIdentityNr sanitizeLocationInfo() {
        return new CellIdentityNr(CellInfo.UNAVAILABLE, CellInfo.UNAVAILABLE, mNrArfcn,
                mBands, mMccStr, mMncStr, CellInfo.UNAVAILABLE_LONG, mAlphaLong, mAlphaShort,
                mAdditionalPlmns);
    }

    /** @hide */
    protected void updateGlobalCellId() {
        mGlobalCellId = null;
        String plmn = getPlmn();
        if (plmn == null) return;

        if (mNci == CellInfo.UNAVAILABLE_LONG) return;

        mGlobalCellId = plmn + formatSimple("%09x", mNci);
    }

    /**
     * @return a CellLocation object for this CellIdentity.
     * @hide
     */
    @NonNull
    @Override
    public CellLocation asCellLocation() {
        GsmCellLocation cl = new GsmCellLocation();
        int tac = mTac != CellInfo.UNAVAILABLE ? mTac : -1;
        cl.setLacAndCid(tac, -1);
        cl.setPsc(0);
        return cl;
    }

    @Override
    public int hashCode() {
        return Objects.hash(super.hashCode(), mPci, mTac,
                mNrArfcn, Arrays.hashCode(mBands), mNci, mAdditionalPlmns.hashCode());
    }

    @Override
    public boolean equals(Object other) {
        if (this == other) {
            return true;
        }

        if (!(other instanceof CellIdentityNr)) {
            return false;
        }

        CellIdentityNr o = (CellIdentityNr) other;
        return super.equals(o) && mPci == o.mPci && mTac == o.mTac && mNrArfcn == o.mNrArfcn
                && Arrays.equals(mBands, o.mBands) && mNci == o.mNci
                && mAdditionalPlmns.equals(o.mAdditionalPlmns);
    }

    /**
     * Get the NR(New Radio 5G) Cell Identity.
     *
     * @return The 36-bit NR Cell Identity in range [0, 68719476735] or
     *         {@link CellInfo#UNAVAILABLE_LONG} if unknown.
     */
    public long getNci() {
        return mNci;
    }

    /**
     * Get the New Radio Absolute Radio Frequency Channel Number.
     *
     * Reference: 3GPP TS 38.101-1 section 5.4.2.1 NR-ARFCN and channel raster.
     * Reference: 3GPP TS 38.101-2 section 5.4.2.1 NR-ARFCN and channel raster.
     *
     * @return Integer value in range [0, 3279165] or {@link CellInfo#UNAVAILABLE} if unknown.
     */
    @IntRange(from = 0, to = 3279165)
    public int getNrarfcn() {
        return mNrArfcn;
    }

    /**
     * Get bands of the cell
     *
     * Reference: TS 38.101-1 table 5.2-1
     * Reference: TS 38.101-2 table 5.2-1
     *
     * @return Array of band number or empty array if not available.
     */
    @NgranBand
    @NonNull
    public int[] getBands() {
        return Arrays.copyOf(mBands, mBands.length);
    }

    /**
     * Get the physical cell id.
     * @return Integer value in range [0, 1007] or {@link CellInfo#UNAVAILABLE} if unknown.
     */
    @IntRange(from = 0, to = 1007)
    public int getPci() {
        return mPci;
    }

    /**
     * Get the tracking area code.
     * @return a 24 bit integer or {@link CellInfo#UNAVAILABLE} if unknown.
     */
    @IntRange(from = 0, to = 16777215)
    public int getTac() {
        return mTac;
    }

    /**
     * @return Mobile Country Code in string format, or {@code null} if unknown.
     */
    @Nullable
    public String getMccString() {
        return mMccStr;
    }

    /**
     * @return Mobile Network Code in string format, or {@code null} if unknown.
     */
    @Nullable
    public String getMncString() {
        return mMncStr;
    }

    /** @hide */
    @Override
    public int getChannelNumber() {
        return mNrArfcn;
    }

    /**
     * @return a list of additional PLMN IDs supported by this cell.
     */
    @NonNull
    public Set<String> getAdditionalPlmns() {
        return Collections.unmodifiableSet(mAdditionalPlmns);
    }

    @Override
    public String toString() {
        return new StringBuilder(TAG + ":{")
                .append(" mPci = ").append(mPci)
                .append(" mTac = ").append(mTac)
                .append(" mNrArfcn = ").append(mNrArfcn)
                .append(" mBands = ").append(Arrays.toString(mBands))
                .append(" mMcc = ").append(mMccStr)
                .append(" mMnc = ").append(mMncStr)
                .append(" mNci = ").append(mNci)
                .append(" mAlphaLong = ").append(mAlphaLong)
                .append(" mAlphaShort = ").append(mAlphaShort)
                .append(" mAdditionalPlmns = ").append(mAdditionalPlmns)
                .append(" }")
                .toString();
    }

    @Override
    public void writeToParcel(Parcel dest, int type) {
        super.writeToParcel(dest, CellInfo.TYPE_NR);
        dest.writeInt(mPci);
        dest.writeInt(mTac);
        dest.writeInt(mNrArfcn);
        dest.writeIntArray(mBands);
        dest.writeLong(mNci);
        dest.writeArraySet(mAdditionalPlmns);
    }

    /** Construct from Parcel, type has already been processed */
    private CellIdentityNr(Parcel in) {
        super(TAG, CellInfo.TYPE_NR, in);
        mPci = in.readInt();
        mTac = in.readInt();
        mNrArfcn = in.readInt();
        mBands = in.createIntArray();
        mNci = in.readLong();
        mAdditionalPlmns = (ArraySet<String>) in.readArraySet(null);

        updateGlobalCellId();
    }

    /** Implement the Parcelable interface */
    public static final @android.annotation.NonNull Creator<CellIdentityNr> CREATOR =
            new Creator<CellIdentityNr>() {
                @Override
                public CellIdentityNr createFromParcel(Parcel in) {
                    // Skip the type info.
                    in.readInt();
                    return createFromParcelBody(in);
                }

                @Override
                public CellIdentityNr[] newArray(int size) {
                    return new CellIdentityNr[size];
                }
            };

    /** @hide */
    protected static CellIdentityNr createFromParcelBody(Parcel in) {
        return new CellIdentityNr(in);
    }
}