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*/

package com.google.refine.commands.recon;

import java.io.IOException;
import java.util.Properties;

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

import org.json.JSONWriter;

import com.google.refine.commands.Command;
import com.google.refine.expr.ExpressionUtils;
import com.google.refine.history.Change;
import com.google.refine.history.HistoryEntry;
import com.google.refine.model.Cell;
import com.google.refine.model.Column;
import com.google.refine.model.Project;
import com.google.refine.model.Recon.Judgment;
import com.google.refine.model.ReconStats;
import com.google.refine.model.changes.CellChange;
import com.google.refine.model.changes.ReconChange;
import com.google.refine.process.QuickHistoryEntryProcess;
import com.google.refine.util.Pool;

public class ReconClearOneCellCommand extends Command {
    @Override
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        try {
            Project project = getProject(request);

            int rowIndex = Integer.parseInt(request.getParameter("row"));
            int cellIndex = Integer.parseInt(request.getParameter("cell"));

            ClearOneCellProcess process = new ClearOneCellProcess(
                project,
                "Clear one cell's recon data",
                rowIndex,
                cellIndex
            );

            HistoryEntry historyEntry = project.processManager.queueProcess(process);
            if (historyEntry != null) {
                /*
                 * If the process is done, write back the cell's data so that the
                 * client side can update its UI right away.
                 */
                JSONWriter writer = new JSONWriter(response.getWriter());

                Pool pool = new Pool();
                Properties options = new Properties();
                options.put("pool", pool);

                writer.object();
                writer.key("code"); writer.value("ok");
                writer.key("historyEntry"); historyEntry.write(writer, options);
                writer.key("cell"); process.newCell.write(writer, options);
                writer.key("pool"); pool.write(writer, options);
                writer.endObject();
            } else {
                respond(response, "{ \"code\" : \"pending\" }");
            }
        } catch (Exception e) {
            respondException(response, e);
        }
    }

    protected static class ClearOneCellProcess extends QuickHistoryEntryProcess {

        final int               rowIndex;
        final int               cellIndex;
        Cell newCell;

        ClearOneCellProcess(
            Project project,
            String briefDescription,
            int rowIndex,
            int cellIndex
        ) {
            super(project, briefDescription);

            this.rowIndex = rowIndex;
            this.cellIndex = cellIndex;
        }

        @Override
        protected HistoryEntry createHistoryEntry(long historyEntryID) throws Exception {
            Cell cell = _project.rows.get(rowIndex).getCell(cellIndex);
            if (cell == null || !ExpressionUtils.isNonBlankData(cell.value)) {
                throw new Exception("Cell is blank or error");
            }

            Column column = _project.columnModel.getColumnByCellIndex(cellIndex);
            if (column == null) {
                throw new Exception("No such column");
            }

            Judgment oldJudgment = cell.recon == null ? Judgment.None : cell.recon.judgment;

            newCell = new Cell(cell.value, null);

            ReconStats stats = column.getReconStats();
            if (stats == null) {
                stats = ReconStats.create(_project, cellIndex);
            } else {
                int newChange = 0;
                int matchChange = 0;

                if (oldJudgment == Judgment.New) {
                    newChange--;
                }
                if (oldJudgment == Judgment.Matched) {
                    matchChange--;
                }

                stats = new ReconStats(
                    stats.nonBlanks + 1,
                    stats.newTopics + newChange,
                    stats.matchedTopics + matchChange);
            }

            String description =
                "Clear recon data for single cell on row " + (rowIndex + 1) +
                ", column " + column.getName() +
                ", containing \"" + cell.value + "\"";

            Change change = new ReconChange(
                new CellChange(rowIndex, cellIndex, cell, newCell),
                column.getName(),
                column.getReconConfig(),
                stats
            );

            return new HistoryEntry(
                historyEntryID, _project, description, null, change);
        }
    }
}