/*
 * This file is part of ComputerCraft - http://www.computercraft.info
 * Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
 * Send enquiries to dratcliffe@gmail.com
 */

package dan200.computercraft.core.tracking;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.function.LongFunction;

public final class TrackingField
{
    private static final Map<String, TrackingField> fields = new HashMap<>();

    public static final TrackingField TASKS = TrackingField.of( "tasks", x -> String.format( "%4d", x ) );
    public static final TrackingField TOTAL_TIME = TrackingField.of( "total", x -> String.format( "%7.1fms", x / 1e6 ) );
    public static final TrackingField AVERAGE_TIME = TrackingField.of( "average", x -> String.format( "%4.1fms", x / 1e6 ) );
    public static final TrackingField MAX_TIME = TrackingField.of( "max", x -> String.format( "%5.1fms", x / 1e6 ) );

    public static final TrackingField SERVER_COUNT = TrackingField.of( "server_count", x -> String.format( "%4d", x ) );
    public static final TrackingField SERVER_TIME = TrackingField.of( "server_time", x -> String.format( "%7.1fms", x / 1e6 ) );

    public static final TrackingField PERIPHERAL_OPS = TrackingField.of( "peripheral", TrackingField::formatDefault );
    public static final TrackingField FS_OPS = TrackingField.of( "fs", TrackingField::formatDefault );
    public static final TrackingField TURTLE_OPS = TrackingField.of( "turtle", TrackingField::formatDefault );

    public static final TrackingField HTTP_REQUESTS = TrackingField.of( "http", TrackingField::formatDefault );
    public static final TrackingField HTTP_UPLOAD = TrackingField.of( "http_upload", TrackingField::formatBytes );
    public static final TrackingField HTTP_DOWNLOAD = TrackingField.of( "http_download", TrackingField::formatBytes );

    public static final TrackingField WEBSOCKET_INCOMING = TrackingField.of( "websocket_incoming", TrackingField::formatBytes );
    public static final TrackingField WEBSOCKET_OUTGOING = TrackingField.of( "websocket_outgoing", TrackingField::formatBytes );

    public static final TrackingField COROUTINES_CREATED = TrackingField.of( "coroutines_created", x -> String.format( "%4d", x ) );
    public static final TrackingField COROUTINES_DISPOSED = TrackingField.of( "coroutines_dead", x -> String.format( "%4d", x ) );

    private final String id;
    private final String translationKey;
    private final LongFunction<String> format;

    public String id()
    {
        return id;
    }

    public String translationKey()
    {
        return translationKey;
    }

    private TrackingField( String id, LongFunction<String> format )
    {
        this.id = id;
        translationKey = "tracking_field.computercraft." + id + ".name";
        this.format = format;
    }

    public String format( long value )
    {
        return format.apply( value );
    }

    public static TrackingField of( String id, LongFunction<String> format )
    {
        TrackingField field = new TrackingField( id, format );
        fields.put( id, field );
        return field;
    }

    public static Map<String, TrackingField> fields()
    {
        return Collections.unmodifiableMap( fields );
    }

    private static String formatDefault( long value )
    {
        return String.format( "%6d", value );
    }

    /**
     * So technically a kibibyte, but let's not argue here.
     */
    private static final int KILOBYTE_SIZE = 1024;

    private static final String SI_PREFIXES = "KMGT";

    private static String formatBytes( long bytes )
    {
        if( bytes < 1024 ) return String.format( "%10d B", bytes );
        int exp = (int) (Math.log( bytes ) / Math.log( KILOBYTE_SIZE ));
        if( exp > SI_PREFIXES.length() ) exp = SI_PREFIXES.length();
        return String.format( "%10.1f %siB", bytes / Math.pow( KILOBYTE_SIZE, exp ), SI_PREFIXES.charAt( exp - 1 ) );
    }
}