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package com.wavefront.ingester;

import wavefront.report.Annotation;

import javax.annotation.Nonnull;
import java.lang.reflect.Array;
import java.util.List;
import java.util.Map;

/**
 * Parses Json inputs to parsable format
 */
public class JsonParser {
    private final Map input;
    private final String UNDERSCORE = "_";
    private final List ignoreFlatten;
    char[] labelsToReplace = new char[]{'-', '.', '/'};

    /***
     * @param ignoreFlatten list of strings that will not be flattened
     */
    public JsonParser(@Nonnull Map input, List ignoreFlatten) {
        this.input = input;
        this.ignoreFlatten = ignoreFlatten;
    }

    /**
     * flattens nested json
     * a : {b : x} -> a_b = x
     * a:[x, y] -> a_0 = x, a_1 = y
     * @param annotations annotations list to insert the final objects
     */
    public void flattenJson(List annotations) {
        for (Map.Entry tagKV : input.entrySet()) {
            flattenJsonInternal(tagKV.getKey(), tagKV.getValue(), annotations);
        }
    }

    private void flattenJsonInternal(String key, Object value, List annotations) {
        if (value == null) {
            annotations.add(Annotation.newBuilder().setKey(labelReplace(key)).setValue("null").build());
        } else if (ignoreFlatten.contains(key) || value instanceof String) {
            annotations.add(Annotation.newBuilder().setKey(labelReplace(key)).setValue(value.toString()).build());
        } else if (value instanceof Map) {
            for (Map.Entry tagKV : ((Map)value).entrySet()) {
                flattenJsonInternal(concatonate(key, tagKV.getKey().toString()), tagKV.getValue(), annotations);
            }
        } else if (value instanceof List) {
            for (int i = 0; i < ((List) value).size(); i++) {
                flattenJsonInternal(concatonate(key, String.valueOf(i)), ((List) value).get(i), annotations);
            }
        } else {
            annotations.add(Annotation.newBuilder().setKey(labelReplace(key)).setValue(value.toString()).build());
        }
    }

    private String concatonate(String s1, String s2) {
        return s1 + UNDERSCORE + s2;
    }
    private String labelReplace(String label) {
        String finalLabel = label;
        for (char charToReplace : labelsToReplace) {
            finalLabel = finalLabel.replace(charToReplace, '_');
        }
        return finalLabel;
    }
}