/*  Copyright (C) 2017-2018 Andreas Shimokawa

    This file is part of Gadgetbridge.

    Gadgetbridge is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published
    by the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    Gadgetbridge is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>. */

package nodomain.freeyourgadget.gadgetbridge.service.devices.huami;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.Map;

import nodomain.freeyourgadget.gadgetbridge.impl.GBDevice;
import nodomain.freeyourgadget.gadgetbridge.util.ArrayUtils;
import nodomain.freeyourgadget.gadgetbridge.util.CheckSums;


public abstract class HuamiFirmwareInfo {

    protected static final byte[] RES_HEADER = new byte[]{ // HMRES resources file (*.res)
            0x48, 0x4d, 0x52, 0x45, 0x53
    };

    protected static final byte[] NEWRES_HEADER = new byte[]{ // NERES resources file (*.res)
            0x4e, 0x45, 0x52, 0x45, 0x53
    };

    protected static final byte[] WATCHFACE_HEADER = new byte[]{
            0x48, 0x4d, 0x44, 0x49, 0x41, 0x4c
    };

    protected static final byte[] FT_HEADER = new byte[]{ // HMZK font file (*.ft, *.ft.xx)
            0x48, 0x4d, 0x5a, 0x4b
    };

    protected static final byte[] NEWFT_HEADER = new byte[]{ // NEZK font file (*.ft, *.ft.xx)
            0x4e, 0x45, 0x5a, 0x4b
    };

    protected static final int FONT_TYPE_OFFSET = 0x9;

    private HuamiFirmwareType firmwareType = HuamiFirmwareType.FIRMWARE;

    public String toVersion(int crc16) {
        String version = getCrcMap().get(crc16);
        if (version == null) {
            switch (firmwareType) {
                case FIRMWARE:
                    version = searchFirmwareVersion(bytes);
                    break;
                case RES:
                    version = "RES " + Integer.toString(bytes[5]);
                    break;
                case RES_COMPRESSED:
                    version = "RES " + Integer.toString(bytes[14]);
                    break;
                case FONT:
                    version = "FONT " + Integer.toString(bytes[4]);
                    break;
                case FONT_LATIN:
                    version = "FONT LATIN " + Integer.toString(bytes[4]);
                    break;
            }
        }
        if (version == null) {
            switch (firmwareType) {
                case FIRMWARE:
                    version = "(unknown)";
                    break;
                case FONT:
                case FONT_LATIN:
                    version = "(unknown font)";
                    break;
                case GPS:
                    version = "(unknown GPS)";
                    break;
                case GPS_CEP:
                    version = "(unknown CEP)";
                    break;
                case GPS_ALMANAC:
                    version = "(unknown ALM)";
                    break;
                case WATCHFACE:
                    version = "(unknown watchface)";
                    break;
            }
        }
        return version;
    }

    public int[] getWhitelistedVersions() {
        return ArrayUtils.toIntArray(getCrcMap().keySet());
    }

    private final int crc16;

    private byte[] bytes;

    public HuamiFirmwareInfo(byte[] bytes) {
        this.bytes = bytes;
        crc16 = CheckSums.getCRC16(bytes);
        firmwareType = determineFirmwareType(bytes);
    }

    public abstract boolean isGenerallyCompatibleWith(GBDevice device);

    public boolean isHeaderValid() {
        return getFirmwareType() != HuamiFirmwareType.INVALID;
    }

    public void checkValid() throws IllegalArgumentException {
    }

    /**
     * Returns the size of the firmware in number of bytes.
     *
     * @return
     */
    public int getSize() {
        return bytes.length;
    }

    public byte[] getBytes() {
        return bytes;
    }

    public int getCrc16() {
        return crc16;
    }

    public int getFirmwareVersion() {
        return getCrc16(); // HACK until we know how to determine the version from the fw bytes
    }

    public HuamiFirmwareType getFirmwareType() {
        return firmwareType;
    }

    protected abstract Map<Integer, String> getCrcMap();

    protected abstract HuamiFirmwareType determineFirmwareType(byte[] bytes);

    protected String searchFirmwareVersion(byte[] fwbytes) {
        ByteBuffer buf = ByteBuffer.wrap(fwbytes);
        buf.order(ByteOrder.BIG_ENDIAN);
        while (buf.remaining() > 3) {
            int word = buf.getInt();
            if (word == 0x5625642e) {
                word = buf.getInt();
                if (word == 0x25642e25) {
                    word = buf.getInt();
                    if (word == 0x642e2564) {
                        word = buf.getInt();
                        if (word == 0x00000000) {
                            byte version[] = new byte[8];
                            buf.get(version);
                            return new String(version);
                        }
                    }
                }
            }
        }
        return null;
    }

}