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*/

package com.google.refine.expr.functions.arrays;

import java.util.List;
import java.util.Properties;

import com.fasterxml.jackson.databind.node.ArrayNode;
import com.google.refine.expr.EvalError;
import com.google.refine.expr.ExpressionUtils;
import com.google.refine.expr.util.JsonValueConverter;
import com.google.refine.grel.ControlFunctionRegistry;
import com.google.refine.grel.Function;

public class Join implements Function {

    @Override
    public Object call(Properties bindings, Object[] args) {
        if (args.length == 2) {
            Object v = args[0];
            Object s = args[1];
            
            if (v != null && s != null && s instanceof String) {
                String separator = (String) s;
                
                if (v.getClass().isArray() || v instanceof List<?> || v instanceof ArrayNode) {
                    StringBuffer sb = new StringBuffer();
                    if (v.getClass().isArray()) {
                        for (Object o : (Object[]) v) {
                            if (o != null) {
                                if (sb.length() > 0) {
                                    sb.append(separator);
                                }
                                sb.append(o.toString());
                            }
                        }
                    } else if (v instanceof ArrayNode) {
                        ArrayNode a = (ArrayNode) v;
                        int l = a.size();
                        
                        for (int i = 0; i < l; i++) {
                            if (sb.length() > 0) {
                                sb.append(separator);
                            }
                            sb.append(JsonValueConverter.convert(a.get(i)).toString());
                        }
                    } else {
                        for (Object o : ExpressionUtils.toObjectList(v)) {
                            if (o != null) {
                                if (sb.length() > 0) {
                                    sb.append(separator);
                                }
                                sb.append(o.toString());
                            }
                        }
                    }
                    
                    return sb.toString();
                }
            }
        }
        return new EvalError(ControlFunctionRegistry.getFunctionName(this) + " expects an array and a string");
    }

    @Override
    public String getDescription() {
        return "Returns the string obtained by joining the array a with the separator sep";
    }
    
    @Override
    public String getParams() {
        return "array a, string sep";
    }
    
    @Override
    public String getReturns() {
        return "string";
    }
}
