package Torello.Java.JSON;

import Torello.Java.StringParse;

import java.util.Vector;
import java.lang.reflect.Parameter;
import java.io.StringWriter;
import javax.json.Json;
import javax.json.stream.JsonGenerator;

/**
 * Generates JSON Requests from lists of Parameter-Names, Parameter-Types and Parameter-Values.
 * 
 * <BR /><BR /><EMBED CLASS='external-html' DATA-FILE-ID=WRITE_JSON>
 */
@Torello.JavaDoc.StaticFunctional
@Torello.JavaDoc.JDHeaderBackgroundImg(EmbedTagFileID="JSON_SERIALIZER_JDHBI")
public class WriteJSON
{
    // This is a "Static" class (static functional)
    private WriteJSON() { }

    /**
     * Converts a list of class types, names &amp; values into a Json Request, as a {@code String}
     * 
     * @param paramTypes These are the types being passed to the JSON Request.
     * 
     * @param paramNames These are the names of the parameters, and these are used for the names
     * of the JSON parameters passed.
     * 
     * @param optionals This is a boolean array that indicates which parameter-values are allowed 
     * to be null.
     * 
     * @param methodName The name of the command being passed over the Web-Socket Connection.
     * 
     * @return Returns the JSON Web-Socket Request as a {@code java.lang.String}
     */
    public static String get(
            Vector<Class<?>> paramTypes, Vector<String> paramNames, boolean[] optionals,
            int webSocketID, String methodName, Object... paramValues
        )
    {
        StringWriter   strW        = new StringWriter();
        JsonGenerator  jGen        = Json.createGenerator(strW);

        jGen.writeStartObject()
            .write("id", webSocketID)
            .write("method", methodName);

        if (paramTypes.size() > 0) 
        {
            Vector<Object> oVec = new Vector<>();
            for (Object o : paramValues) oVec.add(o);

            jGen.writeStartObject("params");
            get(jGen, paramTypes, paramNames, oVec, optionals);
            jGen.writeEnd();
        }
        // else jGen.writeNull("params"); // Is this the right idea?

        jGen.writeEnd();
        jGen.close();

        return strW.toString();
    }

    /**
     * Converts a list of class types, names &amp; values into a series of Json-Generator commands.
     * 
     * @param jGen Because this method may be used recursively, the current generator that is being
     * used must be passed to this method.
     * 
     * @param cVec The list of types for each entity being converted to a Json Request.
     * @param nVec The list of names for each entity being converted to a Json Request.
     * @param oVec The list of values for each entity being converted to a Json Request.
     * @param optArr A {@code boolean[]} array indicating which parameters may be null.
     */
    public static void get(
            JsonGenerator jGen, Vector<Class<?>> cVec, Vector<String> nVec, Vector<Object> oVec,
            boolean[] optArr
        )
    {
        for (int k=0; k < nVec.size(); k++)
        {
            boolean     opt = optArr[k];
            Class<?>    c   = cVec.elementAt(k);
            String      n   = nVec.elementAt(k);
            Object      o   = oVec.elementAt(k);

            if (o == null)
            {
                if (! opt) throw new Error(
                    "The Operating Assertion is that if a Field is null in this class, it must " +
                    "have been declared 'optional.'  Field [" + n + "] is null, but not optional."
                );

                else continue; // Just leave off of the JSON Completely!
            }

            switch (c.getSimpleName())
            {
                case "int"      : 
                case "Integer"  :   jGen.write(n, ((Integer) o).intValue());        break;
                case "boolean"  :
                case "Boolean"  :   jGen.write(n, ((Boolean) o).booleanValue());    break;
                case "String"   :   jGen.write(n, (String) o);                      break;

                case "Number" :
                    if (o instanceof Long)  jGen.write(n, ((Long) o).longValue());
                    else                    jGen.write(n, ((Double) o).doubleValue());
                    break;

                case "int[]" :
                    jGen.writeStartArray(n);
                    for (int i : (int[]) o) jGen.write(i);
                    jGen.writeEnd();
                    break;

                case "boolean[]" :
                    jGen.writeStartArray(n);
                    for (boolean b : (boolean[]) o) jGen.write(b);
                    jGen.writeEnd();
                    break;

                case "String[]" :
                    jGen.writeStartArray(n);
                    for (String s : (String[]) o)
                        if (s == null)  jGen.writeNull();
                        else            jGen.write(s);
                    jGen.writeEnd();
                    break;

                case "Number[]" :
                    jGen.writeStartArray(n);
                    for (Number num : (Number[]) o)
                        if (num == null)                jGen.writeNull();
                        else if (num instanceof Long)   jGen.write(n, ((Long) num).longValue());
                        else                            jGen.write(n, ((Double) num).doubleValue());
                    jGen.writeEnd();
                    break;

                case "int[][]" :
                    jGen.writeStartArray(n);
                    for (int[] iArr : (int[][]) o)
                    {
                        jGen.writeStartArray();
                        for (boolean b : (boolean[]) o) jGen.write(b);
                        jGen.writeEnd();
                    }
                    jGen.writeEnd();
                    break;

                case "boolean[][]" :
                    jGen.writeStartArray(n);
                    for (int[] iArr : (int[][]) o)
                    {
                        jGen.writeStartArray();
                        for (boolean b : (boolean[]) o) jGen.write(b);
                        jGen.writeEnd();
                    }
                    jGen.writeEnd();
                    break;

                case "String[][]" :
                    jGen.writeStartArray(n);
                    for (String[] sArr : (String[][]) o)
                    {
                        jGen.writeStartArray();
                        for (String s : (String[]) o)
                            if (s == null)  jGen.writeNull();
                            else            jGen.write(s);
                        jGen.writeEnd();
                    }
                    jGen.writeEnd();
                    break;


                case "Number[][]" :
                    jGen.writeStartArray(n);
                    NUM_ARR:
                    for (Number[] sArr : (Number[][]) o)
                    {
                        if (sArr == null)
                        { jGen.writeNull(); continue NUM_ARR; }

                        jGen.writeStartArray();
                        for (Number num : (Number[]) o)
                            if (num == null)                jGen.writeNull();
                            else if (num instanceof Long)   jGen.write(n, ((Long) num).longValue());
                            else                            jGen.write(n, ((Double) num).doubleValue());
                        jGen.writeEnd();
                    }
                    jGen.writeEnd();
                    break;

                default:
                    if (c.isArray())
                    {
                        if (! BaseType.class.isAssignableFrom(c.getComponentType()))
                            throw new Error(
                                "One of the Fields [" + n + "] is declared an array, " +
                                "(type " + c.getSimpleName() + "), but the Array Elements do " +
                                "not implement the interface 'BaseType'"
                            );
                        
                        if (StringParse.countCharacters(c.getSimpleName(), '[') > 1)
                            throw new Error(
                                "One of the Fields [" + n + "] is declared an array, " +
                                "(type " + c.getSimpleName() + "), but the Array has a dimension " +
                                "greater than 1.  This was agreed, impossible."
                            );

                        jGen.writeStartArray(n);
                        for (BaseType bt : (BaseType[]) o)
                            if (bt == null) jGen.writeNull();
                            else            bt.toJSON(null, jGen);
                        jGen.writeEnd();
                    }
                    else
                    {
                        if (! BaseType.class.isAssignableFrom(c)) throw new Error(
                            "Field [" + n +"] has a class / type [" + c.getSimpleName() + "], " +
                            "but this class does not implement the interface BaseType!"
                        );

                        else ((BaseType) o).toJSON(n, jGen);
                    }
            }
        }
    }
}