/*
 * Copyright 2014 Robin Stuart
 *
 * 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 uk.org.okapibarcode.backend;

import static uk.org.okapibarcode.backend.HumanReadableLocation.NONE;
import static uk.org.okapibarcode.backend.HumanReadableLocation.TOP;

import uk.org.okapibarcode.graphics.Rectangle;
import uk.org.okapibarcode.graphics.TextBox;

/**
 * <p>Implements <a href="http://en.wikipedia.org/wiki/POSTNET">POSTNET</a> and
 * <a href="http://en.wikipedia.org/wiki/Postal_Alpha_Numeric_Encoding_Technique">PLANET</a>
 * bar code symbologies.
 *
 * <p>POSTNET and PLANET both use numerical input data and include a modulo-10 check digit.
 *
 * @author <a href="mailto:rstuart114@gmail.com">Robin Stuart</a>
 */
public class Postnet extends Symbol {

    /** Whether to encode a POSTNET or PLANET barcode. */
    public enum Mode {
        /** Encode a PLANET barcode. */
        PLANET,
        /** Encode a POSTNET barcode. */
        POSTNET
    }

    private static final String[] PN_TABLE = {
        "LLSSS", "SSSLL", "SSLSL", "SSLLS", "SLSSL", "SLSLS", "SLLSS", "LSSSL", "LSSLS", "LSLSS"
    };

    private static final String[] PL_TABLE = {
        "SSLLL", "LLLSS", "LLSLS", "LLSSL", "LSLLS", "LSLSL", "LSSLL", "SLLLS", "SLLSL", "SLSLL"
    };

    private Mode mode;
    private double moduleWidthRatio;

    /**
     * Creates a new instance, using mode {@link Mode#POSTNET}
     */
    public Postnet() {
        this(Mode.POSTNET);
    }

    /**
     * Creates a new instance, using the specified mode.
     *
     * @param mode the barcode mode (PLANET or POSTNET)
     */
    public Postnet(Mode mode) {
        this.mode = mode;
        this.moduleWidthRatio = 1.5;
        this.default_height = 12;
        this.humanReadableLocation = HumanReadableLocation.NONE;
    }

    /**
     * Sets the barcode mode (PLANET or POSTNET). The default mode is POSTNET.
     *
     * @param mode the barcode mode (PLANET or POSTNET)
     */
    public void setMode(Mode mode) {
        this.mode = mode;
    }

    /**
     * Returns the barcode mode (PLANET or POSTNET). The default mode is POSTNET.
     *
     * @return the barcode mode (PLANET or POSTNET)
     */
    public Mode getMode() {
        return mode;
    }

    /**
     * Sets the ratio of space width to bar width. The default value is {@code 1.5} (spaces are 50% wider than bars).
     *
     * @param moduleWidthRatio the ratio of space width to bar width
     */
    public void setModuleWidthRatio(double moduleWidthRatio) {
        this.moduleWidthRatio = moduleWidthRatio;
    }

    /**
     * Returns the ratio of space width to bar width.
     *
     * @return the ratio of space width to bar width
     */
    public double getModuleWidthRatio() {
        return moduleWidthRatio;
    }

    @Override
    protected void encode() {
        String[] table = (mode == Mode.POSTNET ? PN_TABLE : PL_TABLE);
        encode(table);
    }

    private void encode(String[] table) {

        if (content.length() > 38) {
            throw OkapiInputException.inputTooLong();
        }

        if (!content.matches("[0-9]*")) {
            throw OkapiInputException.invalidCharactersInInput();
        }

        int sum = 0;
        int destLen = 7 + (content.length() * 5);
        StringBuilder dest = new StringBuilder(destLen);
        dest.append('L');

        for (int i = 0; i < content.length(); i++) {
            dest.append(table[content.charAt(i) - '0']);
            sum += content.charAt(i) - '0';
        }

        int checkDigit = (10 - (sum % 10)) % 10;
        infoLine("Check Digit: " + checkDigit);

        dest.append(table[checkDigit]);
        dest.append('L');

        assert dest.length() == destLen;

        infoLine("Encoding: " + dest);
        readable = content;
        pattern = new String[] { dest.toString() };
        row_count = 1;
        row_height = new int[] { -1 };
    }

    @Override
    protected void plotSymbol() {
        int xBlock, shortHeight;
        double x, y, w, h, dx;

        resetPlotElements();

        int baseY;
        if (humanReadableLocation == TOP) {
            baseY = getTheoreticalHumanReadableHeight();
        } else {
            baseY = 0;
        }

        x = 0;
        w = moduleWidth;
        dx = (1 + moduleWidthRatio) * w;
        shortHeight = (int) (0.4 * default_height);
        for (xBlock = 0; xBlock < pattern[0].length(); xBlock++) {
            if (pattern[0].charAt(xBlock) == 'L') {
                y = baseY;
                h = default_height;
            } else {
                y = baseY + default_height - shortHeight;
                h = shortHeight;
            }
            rectangles.add(new Rectangle(x, y, w, h));
            x += dx;
        }

        symbol_width = (int) Math.ceil(((pattern[0].length() - 1) * dx) + w); // final bar doesn't need extra whitespace
        symbol_height = default_height;

        if (humanReadableLocation != NONE && !readable.isEmpty()) {
            double baseline;
            if (humanReadableLocation == TOP) {
                baseline = fontSize;
            } else {
                baseline = symbol_height + fontSize;
            }
            texts.add(new TextBox(0, baseline, symbol_width, readable, humanReadableAlignment));
        }
    }
}