/*
 * Copyright 2007 ZXing authors
 * 
 * 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 com.jwetherell.quick_response_code.qrcode.decoder;

/**
 * <p>
 * See ISO 18004:2006, 6.4.1, Tables 2 and 3. This enum encapsulates the various
 * modes in which data can be encoded to bits in the QR code standard.
 * </p>
 * 
 * @author Sean Owen
 */
public enum Mode {

    TERMINATOR(new int[] { 0, 0, 0 }, 0x00), // Not really a mode...
    NUMERIC(new int[] { 10, 12, 14 }, 0x01), ALPHANUMERIC(new int[] { 9, 11, 13 }, 0x02), STRUCTURED_APPEND(new int[] { 0, 0, 0 }, 0x03), // Not
                                                                                                                                          // supported
    BYTE(new int[] { 8, 16, 16 }, 0x04), ECI(new int[] { 0, 0, 0 }, 0x07), // character
                                                                           // counts
                                                                           // don't
                                                                           // apply
    KANJI(new int[] { 8, 10, 12 }, 0x08), FNC1_FIRST_POSITION(new int[] { 0, 0, 0 }, 0x05), FNC1_SECOND_POSITION(new int[] { 0, 0, 0 }, 0x09),
    /** See GBT 18284-2000; "Hanzi" is a transliteration of this mode name. */
    HANZI(new int[] { 8, 10, 12 }, 0x0D);

    private final int[] characterCountBitsForVersions;
    private final int bits;

    Mode(int[] characterCountBitsForVersions, int bits) {
        this.characterCountBitsForVersions = characterCountBitsForVersions;
        this.bits = bits;
    }

    /**
     * @param bits
     *            four bits encoding a QR Code data mode
     * @return Mode encoded by these bits
     * @throws IllegalArgumentException
     *             if bits do not correspond to a known mode
     */
    public static Mode forBits(int bits) {
        switch (bits) {
            case 0x0:
                return TERMINATOR;
            case 0x1:
                return NUMERIC;
            case 0x2:
                return ALPHANUMERIC;
            case 0x3:
                return STRUCTURED_APPEND;
            case 0x4:
                return BYTE;
            case 0x5:
                return FNC1_FIRST_POSITION;
            case 0x7:
                return ECI;
            case 0x8:
                return KANJI;
            case 0x9:
                return FNC1_SECOND_POSITION;
            case 0xD:
                // 0xD is defined in GBT 18284-2000, may not be supported in
                // foreign country
                return HANZI;
            default:
                throw new IllegalArgumentException();
        }
    }

    /**
     * @param version
     *            version in question
     * @return number of bits used, in this QR Code symbol {@link Version}, to
     *         encode the count of characters that will follow encoded in this
     *         Mode
     */
    public int getCharacterCountBits(Version version) {
        int number = version.getVersionNumber();
        int offset;
        if (number <= 9) {
            offset = 0;
        } else if (number <= 26) {
            offset = 1;
        } else {
            offset = 2;
        }
        return characterCountBitsForVersions[offset];
    }

    public int getBits() {
        return bits;
    }

}
