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*/

package com.google.refine.operations.cell;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.google.refine.browsing.EngineConfig;
import com.google.refine.browsing.RowVisitor;
import com.google.refine.expr.Evaluable;
import com.google.refine.expr.ExpressionUtils;
import com.google.refine.expr.MetaParser;
import com.google.refine.model.Cell;
import com.google.refine.model.Column;
import com.google.refine.model.Project;
import com.google.refine.model.Row;
import com.google.refine.model.changes.CellChange;
import com.google.refine.operations.EngineDependentMassCellOperation;
import com.google.refine.util.ParsingUtilities;
import com.google.refine.util.StringUtils;

public class MassEditOperation extends EngineDependentMassCellOperation {
    final protected String         _expression;
    final protected List<Edit>     _edits;
    
    static public class Edit  {
        @JsonProperty("from")
        final public List<String>     from;
        @JsonProperty("fromBlank")
        final public boolean          fromBlank;
        @JsonProperty("fromError")
        final public boolean          fromError;
        @JsonProperty("to")
        final public Serializable     to;
        
        public Edit(
            List<String> from,
            boolean fromBlank,
            boolean fromError,
            Serializable to) {
            this.from = from;
            this.fromBlank = fromBlank || (from.size() == 1 && from.get(0).length() == 0);
            this.fromError = fromError;
            this.to = to;
        }
        
        @JsonCreator
        public static Edit deserialize(
                @JsonProperty("from")
                List<String> from,
                @JsonProperty("fromBlank")
                boolean fromBlank,
                @JsonProperty("fromError")
                boolean fromError,
                @JsonProperty("to")
                Object to,
                @JsonProperty("type")
                String type) {
            Serializable serializable = (Serializable)to;
            if ("date".equals(type)) {
                serializable = ParsingUtilities.stringToDate((String) to);
            }
            return new Edit(from == null ? new ArrayList<>() : from,
                    fromBlank, fromError, serializable);
        }
    }
    
    @JsonCreator
    public MassEditOperation(
    		@JsonProperty("engineConfig")
    		EngineConfig engineConfig,
    		@JsonProperty("columnName")
    		String columnName,
    		@JsonProperty("expression")
    		String expression,
    		@JsonProperty("edits")
    		List<Edit> edits) {
        super(engineConfig, columnName, true);
        _expression = expression;
        _edits = edits;
    }
    
    @JsonProperty("expression")
    public String getExpression() {
        return _expression;
    }
    
    @JsonProperty("edits")
    public List<Edit> getEdits() {
        return _edits;
    }

    @Override
    protected String getBriefDescription(Project project) {
        return "Mass edit cells in column " + _columnName;
    }

    @Override
    protected String createDescription(Column column,
            List<CellChange> cellChanges) {
        
        return "Mass edit " + cellChanges.size() + 
            " cells in column " + column.getName();
    }

    @Override
    protected RowVisitor createRowVisitor(Project project, List<CellChange> cellChanges, long historyEntryID) throws Exception {
        Column column = project.columnModel.getColumnByName(_columnName);
        
        Evaluable eval = MetaParser.parse(_expression);
        Properties bindings = ExpressionUtils.createBindings(project);
        
        Map<String, Serializable> fromTo = new HashMap<String, Serializable>();
        Serializable fromBlankTo = null;
        Serializable fromErrorTo = null;
        
        for (Edit edit : _edits) {
            for (String s : edit.from) {
                fromTo.put(s, edit.to);
            }
            
            // the last edit wins
            if (edit.fromBlank) {
                fromBlankTo = edit.to;
            }
            if (edit.fromError) {
                fromErrorTo = edit.to;
            }
        }
        
        return new RowVisitor() {
            int                         cellIndex;
            Properties                  bindings;
            List<CellChange>            cellChanges;
            Evaluable                   eval;
            
            Map<String, Serializable>   fromTo;
            Serializable                fromBlankTo;
            Serializable                fromErrorTo;
            
            public RowVisitor init(
                int cellIndex, 
                Properties bindings, 
                List<CellChange> cellChanges, 
                Evaluable eval, 
                Map<String, Serializable> fromTo,
                Serializable fromBlankTo,
                Serializable fromErrorTo
            ) {
                this.cellIndex = cellIndex;
                this.bindings = bindings;
                this.cellChanges = cellChanges;
                this.eval = eval;
                this.fromTo = fromTo;
                this.fromBlankTo = fromBlankTo;
                this.fromErrorTo = fromErrorTo;
                return this;
            }
            
            @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) {
                Cell cell = row.getCell(cellIndex);
                Cell newCell = null;
                
                ExpressionUtils.bind(bindings, row, rowIndex, _columnName, cell);
                
                Object v = eval.evaluate(bindings);
                if (ExpressionUtils.isError(v)) {
                    if (fromErrorTo != null) {
                        newCell = new Cell(fromErrorTo, (cell != null) ? cell.recon : null);
                    }
                } else if (ExpressionUtils.isNonBlankData(v)) {
                    String from = StringUtils.toString(v);
                    Serializable to = fromTo.get(from);
                    if (to != null) {
                        newCell = new Cell(to, (cell != null) ? cell.recon : null);
                    }
                } else {
                    if (fromBlankTo != null) {
                        newCell = new Cell(fromBlankTo, (cell != null) ? cell.recon : null);
                    }
                }
                
                if (newCell != null) {
                    CellChange cellChange = new CellChange(rowIndex, cellIndex, cell, newCell);
                    cellChanges.add(cellChange);
                }
                return false;
            }
        }.init(column.getCellIndex(), bindings, cellChanges, eval, fromTo, fromBlankTo, fromErrorTo);
    }
}
