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

import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
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.grel.ControlFunctionRegistry;
import com.google.refine.grel.Function;
import com.google.refine.util.JSONUtilities;

public class Sort implements Function {

    @Override
    @SuppressWarnings({ "unchecked", "rawtypes" })
    public Object call(Properties bindings, Object[] args) {
        if (args.length == 1) {
            Object v = args[0];
            if (v != null) {
                if (v.getClass().isArray()) {
                    Object[] a = (Object[]) v;
                    Comparable[] r = new Comparable[a.length];
                    for (int i = 0; i < r.length; i++) {
                        if (a[i] instanceof Comparable) {
                            r[i] = (Comparable) a[i];
                        } else if (a[i] == null) {
                            r[i] = null;
                        } else {
                            return new EvalError(ControlFunctionRegistry.getFunctionName(this) + " expects an array of uniform type");
                        }
                    }
                    Arrays.sort(r, Comparator.nullsLast(Comparator.naturalOrder()));
                    return r;
                } else if (v instanceof ArrayNode) {
                    // FIXME: Probably need a test for this
                    // Comparable[] is a (slight) lie since nulls can be included, but our comparator will handle them
                    Comparable[] r = (Comparable[]) JSONUtilities.toSortableArray((ArrayNode) v);
                    Arrays.sort(r, Comparator.nullsLast(Comparator.naturalOrder()));
                    return r;
                } else if (v instanceof List<?>) {
                    List<? extends Comparable<Object>> a = (List<? extends Comparable<Object>>) v;
                    Collections.sort(a, Comparator.nullsLast(Comparator.naturalOrder()));
                    return a;
                }
            }
        }
        return new EvalError(ControlFunctionRegistry.getFunctionName(this) + " expects an array");
    }

    @Override
    public String getDescription() {
        return "Sorts array a";
    }
    
    @Override
    public String getParams() {
        return "array a of uniform type";
    }
    
    @Override
    public String getReturns() {
        return "array";
    }
}
