package org.ibex.js;

import java.io.Reader;
import java.io.IOException;
import java.io.InputStream;
import org.ibex.util.*;

public class JSU {

    public static final JS[] emptyArgs = new JS[] { };

    public static InputStream getInputStream(JS j) throws IOException {
        while(j != null && j instanceof JS.Clone) j = j.unclone();
        if (j != null && j instanceof Fountain) return ((Fountain)j).getInputStream();
        return null;
    }

    /** returns a Pausable which will restart the context;
     *  expects a value to be pushed onto the stack when unpaused. */
    public static Pausable pause() throws Pausable.NotPausableException {
        Interpreter i = Interpreter.current();
        i.pause();
        return i;
    }

    /** Coerce a JS object into a boolean. */
    public static boolean toBoolean(JS o) {
        if(o == null) return false;
        if(o instanceof JSNumber) return ((JSNumber)o).toBoolean();
        if(o instanceof JSString) return ((JSString)o).s.length() != 0;
        return true;
    }

    //#repeat long/int/double/float toLong/toInt/toDouble/toFloat Long/Integer/Double/Float parseLong/parseInt/parseDouble/parseFloat
    /** Coerce a JS object to a long. */
    public static long toLong(JS o) throws JSExn {
        if(o == null) return 0;
        if(o instanceof JSNumber) return ((JSNumber)o).toLong();
        if(o instanceof JSString) return Long.parseLong(o.coerceToString());
        throw new JSExn("can't coerce a " + o.getClass().getName() + " to a number");
    }
    //#end
    
    /** Coerce a JS object to a String. */
    public static String toString(JS o) throws JSExn {
        if(o == null) return "null";
        return o.coerceToString();
    }

    
    public static boolean isInt(JS o) {
        if(o == null) return true;
        if(o instanceof JSNumber.I) return true;
        if(o instanceof JSNumber.B) return false;
        if(o instanceof JSNumber) {
            JSNumber n = (JSNumber) o;
            return n.toInt() == n.toDouble();
        }
        if(o instanceof JSString) {
            String s = ((JSString)o).s;
            for(int i=0;i<s.length();i++)
                if(s.charAt(i) < '0' || s.charAt(i) > '9') return false;
            return true;
        }
        return false;
    }
    
    public static boolean isString(JS o) {
        if(o instanceof JSString) return true;
        return false;
    }
    
    // Instance Methods ////////////////////////////////////////////////////////////////////
 
    public final static JS NaN = new JSNumber.D(Double.NaN);
    public final static JS ZERO = new JSNumber.I(0);
    public final static JS ONE = new JSNumber.I(1);
    public final static JS MATH = new JSMath();
        
    public static final JS T = new JSNumber.B(true);
    public static final JS F = new JSNumber.B(false);

    public static final JS B(boolean b) { return b ? T : F; }
    public static final JS B(int i) { return i==0 ? F : T; }
    
    private static final int CACHE_SIZE = 65536 / 4; // must be a power of two
    private static final JSString[] stringCache = new JSString[CACHE_SIZE];
    public static final JS S(String s) {
        if(s == null) return null;
        int slot = s.hashCode()&(CACHE_SIZE-1);
        JSString ret = stringCache[slot];
        if(ret == null || !ret.s.equals(s)) stringCache[slot] = ret = new JSString(s);
        return ret;
    }
    public static final JS S(String s, boolean intern) { return intern ? JSString.intern(s) : S(s); }

    public static final JS N(double d) { return new JSNumber.D(d); }
    public static final JS N(long l) { return new JSNumber.L(l); }
    
    public static final JS N(Number n) {
        if(n instanceof Integer) return N(n.intValue());
        if(n instanceof Long) return N(n.longValue());
        return N(n.doubleValue());
    }

    private static final JSNumber.I negone = new JSNumber.I(-1);
    private static final JSNumber.I[] icache = new JSNumber.I[128];
    static { for (int i=0; i < icache.length; i++) icache[i] = new JSNumber.I(i); }
    public static final JS N(int i) {
        return i == -1 ? negone : i >= 0 && i < icache.length ? icache[i] : new JSNumber.I(i);
    }

    /** Internal method for coercing to String without throwing a JSExn. */
    public static String str(JS o) {
        try { return toString(o); }
        catch(JSExn e) { return o.toString(); }
    }


    // Static Interpreter Control Methods ///////////////////////////////////////////////////////////////

    public static JS fromReader(String sourceName, int firstLine, Reader source) throws IOException {
        return Parser.fromReader(sourceName, firstLine, source); }

    public static JS cloneWithNewGlobalScope(JS js, JS s) {
        return js instanceof JSFunction ?  ((JSFunction)js)._cloneWithNewParentScope(new JSScope.Top(s)) : js; }

    /** log a message with the current JavaScript sourceName/line */
    public static void log(Object message) { info(message); }
    public static void debug(Object message) { Log.debug(Interpreter.getSourceName() + ":" + Interpreter.getLine(), message); }
    public static void info(Object message) { Log.info(Interpreter.getSourceName() + ":" + Interpreter.getLine(), message); }
    public static void warn(Object message) { Log.warn(Interpreter.getSourceName() + ":" + Interpreter.getLine(), message); }
    public static void error(Object message) { Log.error(Interpreter.getSourceName() + ":" + Interpreter.getLine(), message); }
}