/*
 * [CanadaPostageRates.java]
 *
 * Summary: Probe Canadian post office to find the latest postage rates to post at http://mindprod.com/jgloss/postage.html.
 *
 * Copyright: (c) 2014-2017 Roedy Green, Canadian Mind Products, http://mindprod.com
 *
 * Licence: This software may be copied and used freely for any purpose but military.
 *          http://mindprod.com/contact/nonmil.html
 *
 * Requires: JDK 1.8+
 *
 * Created with: JetBrains IntelliJ IDEA IDE http://www.jetbrains.com/idea/
 *
 * Version History:
 *  1.0 2014-04-06 initial release
 */
package com.mindprod.repair;

import com.mindprod.common18.BigDate;
import com.mindprod.common18.ST;
import com.mindprod.fastcat.FastCat;
import com.mindprod.http.Get;
import com.mindprod.hunkio.HunkIO;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.text.DecimalFormat;
import java.util.concurrent.TimeUnit;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import static java.lang.System.*;

/**
 * Probe Canadian post office to find the latest postage rates to post at http://mindprod.com/jgloss/postage.html.
 * Trigger with E:\com\mindprod\repair\GrabPostageRates.exe
 *
 * @author Roedy Green, Canadian Mind Products
 * @version 1.0 2014-04-06 initial release
 * @see USPostageRates
 * @since 2014-04-06
 */
class CanadaPostageRates
    {
    private static final int[] LOW_GRAMS_ON_WEIGHT_CLASS = { 0, 30, 50 };

    private static final int[] HIGH_GRAMS_ON_WEIGHT_CLASS = { 30, 50, 100 };

    private static final Pattern FIND_DOLLAR = Pattern.compile( ">\\s*\\$([0-9.]+)\\s*<" );

    /**
     * format for display and input of sale amount
     */
    private static final DecimalFormat RATIOFORMAT =
            new DecimalFormat( "#,##0.00" );

    // they have three variants
    // can 0-30g Permanent (P) stamps $0.85
    // int 0-30g Stamps(s) $2.50
    // usa 0-30g Stamp(s) $1.20
    // https://www.canadapost.ca/cpo/mc/personal/postalcode/fpc.jsf now has summary.
    private static final String[] CANADIAN_DESCRIPTIONS_FOR_COUNTRIES = { "letter within Canada",
            "letter to the USA",
            "international letter" };

    private static final String[] CANADIAN_DESCRIPTIONS_FOR_WEIGHTS = { "light", "heavy", "overweight" };

    /**
     * stringe just before the prices we want
     */
    private static final String LEAD = "<h4 class=\"letterspacing_halfpixel\">Postal Rates</h4>";

    // get data direct from canada post.  Else get in indirectly from downloaded file.
    private static final boolean DIRECT = true;

    /**
     * cost of one basic Canadian stamp, used for computing ratios
     */
    private static double canadianBaseRate;

    /**
     * used to alternate stripes
     */
    private static int lineCounter;

    private static String calcCanadianDescription( int country, int weight )
        {
        return CANADIAN_DESCRIPTIONS_FOR_WEIGHTS[ weight ] + " " + CANADIAN_DESCRIPTIONS_FOR_COUNTRIES[ country ];
        }

    private static String generateOneCanadianTableLine( final String desc, final int weightClass, final String price )
        {
        // generate something like this:
        // <tr class="stripe1"><td>$0.85</td><td>1.00</td><td>light letter within Canada</td><td>0 to 30 grams</td></tr>
        // group lines by threes, alternating light/dark backgrounds
        final String css = ( lineCounter++ / 3 % 2 == 0 ) ? "stripe1" : "stripe2";
        final int fromGrams = LOW_GRAMS_ON_WEIGHT_CLASS[ weightClass ];
        final int toGrams = HIGH_GRAMS_ON_WEIGHT_CLASS[ weightClass ];
        final FastCat sb = new FastCat( 17 );
        sb.append( "<tr class=\"", css, "\">" );
        sb.append( "<td>$", price, "</td>" );
        sb.append( "<td>", RATIOFORMAT.format( Double.parseDouble( price ) / canadianBaseRate ), "</td>" );
        sb.append( "<td>", desc, "</td>" );
        sb.append( "<td>", fromGrams, " to ", toGrams, " grams</td></tr>" );
        return sb.toString();
        }

    static String probeAllCanadianPrices() throws java.io.IOException
        {
        String result;
        if ( DIRECT )
            {
            try
                {
                final Get get = new Get();
                get.setInstanceFollowRedirects( true );
                get.setConnectTimeout( ( int ) TimeUnit.SECONDS.toMillis( 40 ) );
                // fails with too too many redirects
                // https://www.canadapost.ca/cpotools/apps/far/business/findARate?execution=e1s1
                result = get.send( new URL( "https://www.canadapost.ca/cpo/mc/personal/postalcode/fpc.jsf" ), Get.UTF8 );
                }
            catch ( MalformedURLException e )
                {
                return ">>>bad url";
                }
            }
        else
            {
            // manually save https://www.canadapost.ca/cpo/mc/personal/postalcode/fpc.jsf to C:\temp\canrates.html
            File source = new File( "C:/temp/canrates.html" );
            assert source.exists() : source.toString() + " is missing.";
            result = HunkIO.readEntireFile( new File( "C:/temp/canrates.html" ), HunkIO.UTF8 );
            }
        assert !ST.isEmpty( result ) : "missing raw data";
        // trim off chunk at front.
        int p = result.indexOf( LEAD );
        if ( p < 0 )
            {
            throw new IllegalArgumentException( "corrupt data. Missing lead." );
            }
        result = result.substring( p + LEAD.length() );
        // extract 3 rows of 3 numbers
        String[] price = new String[ 9 ];
        Matcher m = FIND_DOLLAR.matcher( result );
        for ( int i = 0; i < 9; i++ )
            {
            if ( m.find() )
                {
                price[ i ] = m.group( 1 );
                }
            else
                {
                throw new IllegalArgumentException( "corrupt data. Missing $ value." );
                }
            }
        canadianBaseRate = Double.parseDouble( price[ 0 ] );
        final String prelude1 = "<table class=\"standard\"><caption class=\"hidden\">Canadian Postage Rates</caption> <colgroup><col\n" +
                                "style=\"text-align:right\"> <col style=\"text-align:right\"></colgroup>\n" +
                                "<thead><tr><th colspan=\"4\" style=\"text-align:center\">Canadian Postage\n" +
                                "Rates</th></tr>\n" +
                                "<tr><th colspan=\"4\" style=\"text-align:center\"><!-- macro Revised ";
        final String prelude2 = BigDate.localToday().toString();
        final String prelude3 = " --></th></tr>\n" +
                                "<tr><th>Cost $CAD</th>\n" +
                                "<th>Ratio</th>\n" +
                                "<th>Type</th>\n" +
                                "<th>Weight</th></tr></thead>\n" +
                                "<tbody>";
        final String postlude = "</tbody></table>";
        final FastCat sb = new FastCat( 13 );
        sb.append( prelude1, prelude2, prelude3 );
        int j = 0;
        for ( int country = 0; country < 3; country++ )
            {
            for ( int weightClass = 0; weightClass < 3; weightClass++ )
                {
                final String desc = calcCanadianDescription( country, weightClass );
                sb.append( generateOneCanadianTableLine( desc, weightClass, price[ j++ ] ) );
                }
            }
        sb.append( postlude );
        return sb.toSeparatedList( '\n' );
        }

    public static void main( String[] args ) throws IOException
        {
        final String guts = probeAllCanadianPrices();
        out.println( guts );
        HunkIO.writeEntireFile( new File( "E:/mindprod/jgloss/include/postageratesforcanada.htmlfrag" ), guts, HunkIO.UTF8 );
        }
    }