package com.ngMAT.appl.genericservlet;

import  java.util.Hashtable;
import  java.util.Vector;
import  com.ngMAT.HTML.Anchor;
import  com.ngMAT.HTML.HTMLComponent;
import  com.ngMAT.HTML.HTMLComponentVector;
import  com.ngMAT.HTML.HTMLSpace;
import  com.ngMAT.HTML.HTMLTemplate;
import  com.ngMAT.HTML.InsertionTag;
import  com.ngMAT.HTML.ParsedTable;


public abstract class PartitionedListServlet extends com.ngMAT.appl.genericservlet.GenericServlet
{
    public HTMLComponent process (GenericServletContext context)
    {
        PartitionedListServletConfig config = (PartitionedListServletConfig)context.getConfig();
        HTMLTemplate template = context.getTemplate (config.getTemplateName (context));
        ParsedTable pt = (ParsedTable)template.getParsedTable (config.getListName());
        PartitionedData sd = (PartitionedData)context.getSessionValue (config.getSessionDataName (context));
        if (sd == null)
        {
            sd = new PartitionedData (context, pt);
            sd.refresh_required = true;
        }
        _processCommand (context, template, sd);
        if (sd.refresh_required)
        {
            String _lpp = pt.getParameter ("lines_per_page");
            if (_lpp != null) sd.lines_per_page = Integer.parseInt (_lpp);
            refreshData (context, sd);
            sd.refresh();
            sd.refresh_required = false;
            context.setSessionValue (config.getSessionDataName (context), sd);
        }
        if (sd.page_top_index >= sd.data.size())
        {
            sd.page_top_index = Math.max (sd.data.size() - sd.lines_per_page, 0);
        }
        else if (sd.page_top_index < 0) sd.page_top_index = 0;

        _processSurrounding (context, sd, template);
        int index = sd.page_top_index;
        for (int i = 0; i < sd.lines_per_page && index < sd.data.size(); i++, index++)
        {
            HTMLTemplate    row = pt.getRowTemplate();
            processRowFilling (context, sd, index, row);
            pt.addRow (row);
        }
        return template;
    }

    private void    _processCommand (GenericServletContext context, HTMLTemplate template, PartitionedData sd)
    {
        String command = context.getParameter ("command");
        if (command == null) return;

        if (command.equalsIgnoreCase ("refresh"))
            sd.refresh_required = true;
        else if (command.equalsIgnoreCase ("prev"))
            sd.page_top_index -= sd.lines_per_page;
        else if (command.equalsIgnoreCase ("next"))
            sd.page_top_index += sd.lines_per_page;
        else if (command.equalsIgnoreCase ("jump"))
            processJump (context, template, sd);
        else
            processCommand (context, template, sd);
    }

    private void    processJump (GenericServletContext context, HTMLTemplate template, PartitionedData sd)
    {
        int page = context.getIntParameter ("page", 1) - 1;
        sd.page_top_index = sd.lines_per_page * page;
    }

    public  void    processCommand (GenericServletContext context, HTMLTemplate template, PartitionedData sd)
    {
    }


    public  void    _processSurrounding (GenericServletContext context, PartitionedData data, HTMLTemplate template)
    {
        PartitionedListServletConfig config = (PartitionedListServletConfig)context.getConfig();
        InsertionTag tag = template.getInsertionTag (config.getListName() + ".pages");
        if (tag != null)
        {
            tag.setInsertedComponent (createPageJumpAnchors (context, data));
        }
        processSurrounding (context, data, template);
    }


    private HTMLComponent   createPageJumpAnchors (GenericServletContext context, PartitionedData data)
    {
        PartitionedListServletConfig config = (PartitionedListServletConfig)context.getConfig();
        int max_page_number = data.data.size() / data.lines_per_page;
        if (data.lines_per_page * max_page_number < data.data.size()) max_page_number++;
        HTMLComponentVector hcv = new HTMLComponentVector();
        String _uri = config.getUriForHere (context);
        _uri += (_uri.indexOf ("?") < 0 ? "?" : "&") + "command=jump&page=";
        HTMLSpace spc = new HTMLSpace (2);
        for (int i = 1; i <= max_page_number; i++)
        {
            if (i > 1) hcv.addElement (spc);
            Anchor a = new Anchor (_uri + i, "" + i);
            hcv.addElement (a);
        }
        return hcv;
    }
    public  abstract    void    refreshData (GenericServletContext context, PartitionedData data);
    public  abstract    void    processSurrounding (GenericServletContext context, PartitionedData data,
                                            HTMLTemplate template);
    public  abstract    void    processRowFilling (GenericServletContext context, PartitionedData data,
                                            int index, HTMLTemplate row);

    public  class   PartitionedData
    {
        public  Vector  data;
        public  int lines_per_page = 10;
        public  int page_top_index = 0;
        public  boolean refresh_required = false;

        public  Hashtable   optional_data = new Hashtable();

        private PartitionedData (GenericServletContext context, ParsedTable pt)
        {
            PartitionedListServletConfig config = (PartitionedListServletConfig)context.getConfig();
            String s = pt.getParameter ("maxrows");
            if (s != null)
                lines_per_page = Integer.parseInt (s);
            else
                lines_per_page = config.getDefaultLinesPerPage (context);
        }
        public  void    refresh()
        {
            page_top_index = 0;
        }
    }
}