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*/

package com.google.refine.commands.row;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.json.JSONException;
import org.json.JSONObject;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonInclude.Include;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonUnwrapped;
import com.google.refine.browsing.Engine;
import com.google.refine.browsing.Engine.Mode;
import com.google.refine.browsing.FilteredRecords;
import com.google.refine.browsing.FilteredRows;
import com.google.refine.browsing.RecordVisitor;
import com.google.refine.browsing.RowVisitor;
import com.google.refine.commands.Command;
import com.google.refine.importing.ImportingJob;
import com.google.refine.importing.ImportingManager;
import com.google.refine.model.Cell;
import com.google.refine.model.Project;
import com.google.refine.model.Record;
import com.google.refine.model.Row;
import com.google.refine.sorting.SortingConfig;
import com.google.refine.sorting.SortingRecordVisitor;
import com.google.refine.sorting.SortingRowVisitor;
import com.google.refine.util.ParsingUtilities;
import com.google.refine.util.Pool;

public class GetRowsCommand extends Command {
    
    protected static class WrappedRow  {
        @JsonUnwrapped
        protected final Row row;
        @JsonProperty("i")
        protected final int rowIndex;
        @JsonProperty("j")
        @JsonInclude(Include.NON_NULL)
        protected final Integer recordIndex;
        
        protected WrappedRow(Row rowOrRecord, int rowIndex, Integer recordIndex) {
            this.row = rowOrRecord;
            this.rowIndex = rowIndex;
            this.recordIndex = recordIndex;
        }
    }
    
    protected static class JsonResult  {
        @JsonProperty("mode")
        protected final Mode mode;
        @JsonProperty("rows")
        protected final List<WrappedRow> rows;
        @JsonProperty("filtered")
        protected final int filtered;
        @JsonProperty("total")
        protected final int totalCount;
        @JsonProperty("start")
        protected final int start;
        @JsonProperty("limit")
        protected final int limit;
        @JsonProperty("pool")
        protected final Pool pool;
        
        protected JsonResult(Mode mode, List<WrappedRow> rows, int filtered,
                int totalCount, int start, int limit, Pool pool) {
            this.mode = mode;
            this.rows = rows;
            this.filtered = filtered;
            this.totalCount = totalCount;
            this.start = start;
            this.limit = limit;
            this.pool = pool;
        }
    }
    
    @Override
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        internalRespond(request, response);
    }
    
    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        internalRespond(request, response);
    }
    
    protected void internalRespond(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
        
        try {
            Project project = null;
            
            // This command also supports retrieving rows for an importing job.
            String importingJobID = request.getParameter("importingJobID");
            if (importingJobID != null) {
                long jobID = Long.parseLong(importingJobID);
                ImportingJob job = ImportingManager.getJob(jobID);
                if (job != null) {
                    project = job.project;
                }
            }
            if (project == null) {
                project = getProject(request);
            }
            
            Engine engine = getEngine(request, project);
            String callback = request.getParameter("callback");
            
            int start = Math.min(project.rows.size(), Math.max(0, getIntegerParameter(request, "start", 0)));
            int limit = Math.min(project.rows.size() - start, Math.max(0, getIntegerParameter(request, "limit", 20)));
            
            Pool pool = new Pool();
            /* Properties options = new Properties();
            options.put("project", project);
            options.put("reconCandidateOmitTypes", true);
            options.put("pool", pool); */
            
            response.setCharacterEncoding("UTF-8");
            response.setHeader("Content-Type", callback == null ? "application/json" : "text/javascript");
            
            PrintWriter writer = response.getWriter();
            if (callback != null) {
                writer.write(callback);
                writer.write("(");
            }
            
            RowWritingVisitor rwv = new RowWritingVisitor(start, limit);
            
            SortingConfig sortingConfig = null;
            try{
                String json = request.getParameter("sorting");
                JSONObject sortingJson = (json == null) ? null : 
                    ParsingUtilities.evaluateJsonStringToObject(json);
                if (sortingJson != null) {
                    sortingConfig = SortingConfig.reconstruct(sortingJson);
                }
            } catch (JSONException e) {
            }
            
            if (engine.getMode() == Mode.RowBased) {
                FilteredRows filteredRows = engine.getAllFilteredRows();
                RowVisitor visitor = rwv;
                
                if (sortingConfig != null) {
                    SortingRowVisitor srv = new SortingRowVisitor(visitor);
                    
                    srv.initializeFromConfig(project, sortingConfig);
                    if (srv.hasCriteria()) {
                        visitor = srv;
                    }
                }
                filteredRows.accept(project, visitor);
            } else {
                FilteredRecords filteredRecords = engine.getFilteredRecords();
                RecordVisitor visitor = rwv;
                
                if (sortingConfig != null) {
                    SortingRecordVisitor srv = new SortingRecordVisitor(visitor);
                    
                    srv.initializeFromConfig(project, sortingConfig);
                    if (srv.hasCriteria()) {
                        visitor = srv;
                    }
                }
                filteredRecords.accept(project, visitor);
            }
            
            // Pool all the recons occuring in the rows seen
            for(WrappedRow wr : rwv.results) {
                for(Cell c : wr.row.cells) {
                    if(c != null && c.recon != null) {
                        pool.pool(c.recon);
                    }
                }
            }
            
            JsonResult result = new JsonResult(engine.getMode(),
                    rwv.results, rwv.total,
                    engine.getMode() == Mode.RowBased ? project.rows.size() : project.recordModel.getRecordCount(),
                            start, limit, pool);
            
            ParsingUtilities.defaultWriter.writeValue(writer, result);
            if (callback != null) {
                writer.write(")");
            }
            
            // metadata refresh for row mode and record mode
            if (project.getMetadata() != null) {
                project.getMetadata().setRowCount(project.rows.size());
            }
        } catch (Exception e) {
            respondException(response, e);
        }
    }
    
    static protected class RowWritingVisitor implements RowVisitor, RecordVisitor {
        final int           start;
        final int           limit;
        public List<WrappedRow> results;
        
        public int total;
        
        public RowWritingVisitor(int start, int limit) {
            this.start = start;
            this.limit = limit;
            this.results = new ArrayList<>();
        }
        
        @Override
        public void start(Project project) {
            // nothing to do
        }
        
        @Override
        public void end(Project project) {
            // nothing to do
        }
        
        @Override
        public boolean visit(Project project, int rowIndex, Row row) {
            if (total >= start && total < start + limit) {
                internalVisit(project, rowIndex, row);
            }
            total++;
            
            return false;
        }
        
        @Override
        public boolean visit(Project project, Record record) {
            if (total >= start && total < start + limit) {
                internalVisit(project, record);
            }
            total++;
            
            return false;
        }
        
        public boolean internalVisit(Project project, int rowIndex, Row row) {
            results.add(new WrappedRow(row, rowIndex, null));
            return false;
        }
        
        protected boolean internalVisit(Project project, Record record) {
            for (int r = record.fromRowIndex; r < record.toRowIndex; r++) {
                Row row = project.rows.get(r);
                results.add(new WrappedRow(row, r, r == record.fromRowIndex ? record.recordIndex : null));
            }
            return false;
        }
    }
}