// Copyright 2000-2005 the Contributors, as shown in the revision logs.
// Licensed under the Apache Public Source License 2.0 ("the License").
// You may not use this file except in compliance with the License.

package org.ibex.tool;

//import gnu.regexp.*;
import java.util.*;
import java.io.*;

/**
 *   A VERY crude, inefficient Java preprocessor
 *
 *   //#define FOO bar baz       -- replace all instances of token FOO with "bar baz"
 *   //#replace foo/bar baz/bop  -- DUPLICATE everything between here and //#end,
 *                                  replacing foo with bar and baz with bop in the *second* copy
 *   //#switch(EXPR)             -- switch on strings
 *       case "case1":
 *   //#end
 *
 *   //#ifdef FOO                -- includes contents if FOO passed as define to preprocessor
 *       [code]
 *   //#else
 *       [code run if !FOO]
 *   //#endif
 *
 *   Replacements are done on a token basis.  Tokens are defined as a
 *   sequence of characters which all belong to a single class.  The
 *   two character classes are:
 *
 *     - [a-zA-Z0-9_]
 *     - all other non-whitespace characters
 *   
 *   Preprocessor makes use of several optional system properties:
 *
 *    - ibex.tool.preprocessor.define
 *    - ibex.tool.preprocessor.inputdir
 *    - ibex.tool.preprocessor.outputdir
 *
 *   @author adam@ibex.org, crawshaw@ibex.org
 */
public class Preprocessor {

    public static String replaceAll(String source, String regexp, String replaceWith) {
        return source.replaceAll(regexp, replaceWith);
        /*
        try {
            RE re = new RE(regexp, 0, RESyntax.RE_SYNTAX_PERL5);
            return (String)re.substituteAll(source, replaceWith);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
        */
    }

    public static void main(String[] args) throws Exception {
        List defs = new ArrayList();

        String define = System.getProperty("ibex.tool.preprocessor.define");
        if (define != null) {
            StringTokenizer st = new StringTokenizer(define.toUpperCase(), ",");
            while (st.hasMoreTokens()) defs.add(st.nextToken().trim());
        }

        String inputdir = System.getProperty("ibex.tool.preprocessor.inputdir");
        if (inputdir == null) inputdir = "src/";

        String outputdir = System.getProperty("ibex.tool.preprocessor.outputdir");
        if (outputdir == null) outputdir = "build/java/";

        if (args.length == 0) {
            BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
            BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
            
            // process stdin to stdout
            Preprocessor cc = new Preprocessor(br, bw, defs);
            Vector err = cc.process();
            bw.flush();
            
            // handle errors
            boolean errors = false;
            for (int i=0; i < err.size(); i++) {
                if (err.get(i) instanceof Error) errors = true; System.err.println(err.get(i)); }
            if (errors) throw new Exception();
        } else {
            for(int i=0; i<args.length; i++) {
                if (!args[i].endsWith(".java")) continue;
                File source = new File(args[i]);
                File target = new File(replaceAll(args[i], inputdir, outputdir));
                if (target.exists() && target.lastModified() > source.lastModified()) continue;
                System.err.println("preprocessing " + args[i]);
                new File(target.getParent()).mkdirs();
                BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(source)));
                BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(target)));
                Preprocessor cc   = new Preprocessor(br, bw, defs);
                Vector err = cc.process();
                bw.flush();
                boolean errors = false;
                for (int j=0; j < err.size(); j++) {
                    if (err.get(j) instanceof Error) errors = true; System.err.println(err.get(j)); }
                if (errors) System.exit(-1);
            }
        }
    }

    private Reader r;
    private Writer w;
    private LineNumberReader in;
    private PrintWriter out;

    private Hashtable replace = new Hashtable();
    private Hashtable[] repeatreplaces = null;
    private Vector sinceLastRepeat = null;
    private Vector err = new Vector();
    private List defs;

    private int enumSwitch = 0; // number appended to variable used in switch implementation

   
    public Preprocessor(Reader reader, Writer writer, List d) {
        setReader(reader);
        setWriter(writer);
        defs = d;
    }

    public void setReader(Reader reader) { r = reader; if (r != null) in = new LineNumberReader(r); }
    public Reader getReader() { return r; }

    public void setWriter(Writer writer) { w = writer; if (w != null) out = new PrintWriter(w); }
    public Writer getWriter() { return w; }


    /** process data from reader, write to writer, return vector of errors */
    public Vector process() throws IOException {
        err.clear();

        String s = null;
PROCESS:
        while((s = in.readLine()) != null) {
            if (sinceLastRepeat != null) sinceLastRepeat.addElement(s);
            String trimmed = s.trim();

            if (trimmed.startsWith("//#define ")) {
                if (trimmed.length() == 9 || trimmed.charAt(9) != ' ') {
                    err.add(new Error("#define badly formed, ignored")); continue PROCESS;
                }
                int keyStart = indexOfNotWS(trimmed, 9);
                if (keyStart == -1) {
                    err.add(new Error("#define requires KEY")); continue PROCESS;
                }
                int keyEnd = indexOfWS(trimmed, keyStart);

                int macroStart = trimmed.indexOf('(');
                int macroEnd = trimmed.indexOf(')');
                if (macroStart > keyEnd) {
                    // no macro is defined, just make sure something dumb like KEYNA)ME hasn't been done
                    if (macroEnd < keyEnd) { err.add(new Error("#define key contains invalid char: ')'")); continue PROCESS; }
                    macroStart = macroEnd = -1;
                }

                if (macroStart == 0) {
                    err.add(new Error("#define macro requires name")); continue PROCESS;
                } else if (macroStart > 0) {
                    if (macroStart > macroEnd) { err.add(new Error("#define macro badly formed")); continue PROCESS; }
                    if (macroStart+1 == macroEnd) { err.add(new Error("#define macro requires property name")); continue PROCESS; }

                    JSFunctionMacro fm = new JSFunctionMacro();
                    String key = trimmed.substring(keyStart, macroStart);
                    String unbound = trimmed.substring(macroStart +1, macroEnd);
                    int unboundDiv = unbound.indexOf(',');
                    if (unboundDiv == -1) {
                        fm.unbound1 = unbound;
                    } else {
                        fm.unbound1 = unbound.substring(0, unboundDiv);
                        fm.unbound2 = unbound.substring(unboundDiv +1);
                        if (fm.unbound1.length() == 0) { err.add(new Error("#define macro property 1 requires name")); continue PROCESS; }
                        if (fm.unbound2.length() == 0) { err.add(new Error("#define macro property 1 requires name")); continue PROCESS; }
                    }
                    fm.expression = trimmed.substring(keyEnd).trim();
                    replace.put(key, fm);
                } else {
                    String key = trimmed.substring(keyStart, keyEnd);
                    String val = trimmed.substring(keyEnd).trim();
                    replace.put(key, val);
                }
                out.print("\n"); // preserve line numbers
                
            } else if (trimmed.startsWith("//#repeat ")) {
                trimmed = trimmed.substring(9);
                while(trimmed.charAt(trimmed.length() - 1) == '\\') {
                    String s2 = in.readLine().trim();
                    if (s2.startsWith("//")) s2 = s2.substring(2).trim();
                    trimmed = trimmed.substring(0, trimmed.length() - 1) + " " + s2;
                    out.print("\n");  // preserve line numbers
                }
                StringTokenizer st = new StringTokenizer(trimmed, " ");
                repeatreplaces = null;
                while (st.hasMoreTokens()) {
                    String tok = st.nextToken().trim();
                    String key = tok.substring(0, tok.indexOf('/'));
                    String vals = tok.substring(tok.indexOf('/') + 1);
                    StringTokenizer st2 = new StringTokenizer(vals,"/");
                    if(repeatreplaces == null) {
                        repeatreplaces = new Hashtable[st2.countTokens()];
                        for(int i=0;i<repeatreplaces.length;i++) repeatreplaces[i] = (Hashtable) replace.clone();
                    }
                    for(int i=0;st2.hasMoreTokens() && i<repeatreplaces.length;i++)
                        repeatreplaces[i].put(key, st2.nextToken());
                }
                sinceLastRepeat = new Vector();
                out.print("\n"); // preserve line numbers

            } else if (trimmed.startsWith("//#end")) {
                if (sinceLastRepeat == null) { err.add(new Warning("#end orphaned")); continue PROCESS; }
                Hashtable save = replace;
                out.print("\n");
                for(int i=0;i<repeatreplaces.length;i++) {
                    replace = repeatreplaces[i];
                    for(int j=0; j<sinceLastRepeat.size() - 1; j++) out.print(processLine((String)sinceLastRepeat.elementAt(j), true));
                }
                sinceLastRepeat = null;
                replace = save;
            } else if (trimmed.startsWith("//#ifdef")) {
                String expr = trimmed.substring(8).trim().toUpperCase();
                out.println(trimmed);
                boolean useCode = defs.contains(expr);
                for (trimmed = in.readLine().trim(); !trimmed.startsWith("//#endif"); trimmed = in.readLine().trim()) {
                    if (trimmed.startsWith("//#else")) useCode = !useCode;
                    else if (!useCode) out.print("// ");
                    out.print(processLine(trimmed, false));
                }
                out.println("//#endif "+expr);

            } else if (trimmed.startsWith("//#switch") || trimmed.startsWith("//#jsswitch")) {
                int expStart = trimmed.indexOf('(') +1;
                if (expStart < 1) { err.add(new Error("expected ( in #switch")); continue PROCESS; }
                int expEnd = trimmed.lastIndexOf(')');
                if (expEnd == -1) { err.add(new Error("expected ) in #switch")); continue PROCESS; }
                if (expEnd - expStart <= 1) { err.add(new Error("badly formed #switch statement")); continue PROCESS; }
                String expr = trimmed.substring(expStart, expEnd);
                if (trimmed.startsWith("//#jsswitch")) expr = "JSU.toString("+expr+")";
                out.print("final String ccSwitch"+enumSwitch+" = (String)("+expr+");  ");
                out.print("SUCCESS:do { switch(ccSwitch"+enumSwitch+".length()) {\n");

                Hashtable[] byLength = new Hashtable[255];
                String key = null;
                String Default = null;
                for(trimmed = in.readLine().trim(); !trimmed.startsWith("//#end"); trimmed = in.readLine().trim()) {
                    if (trimmed.startsWith("default:")) {
                        Default = processLine(trimmed.substring(8), false);
                        continue;
                    }
                    if (trimmed.startsWith("case ")) {
                        // find key
                        int strStart = trimmed.indexOf('\"') +1;
                        if (strStart < 1) { err.add(new Error("expected opening of String literal")); continue PROCESS; }
                        int strEnd = trimmed.indexOf('\"', strStart);
                        if (strEnd == -1) { err.add(new Error("expected closing of String literal")); continue PROCESS; }
                        key = trimmed.substring(strStart, strEnd);

                        Hashtable thisCase = (Hashtable)byLength[key.length()];
                        if (thisCase == null) byLength[key.length()] = thisCase = new Hashtable();
                        thisCase.put(key, "");

                        // find end of case definition
                        int caseEnd = trimmed.indexOf(':', strEnd) +1;
                        if (caseEnd < 1) { err.add(new Error("expected :")); continue PROCESS; }
                        trimmed = trimmed.substring(caseEnd);
                    }

                    if (key != null) {
                        Hashtable hash = byLength[key.length()];
                        hash.put(key, (String)hash.get(key) + replaceAll(processLine(trimmed, false), "//[^\"]*$", "").trim() + "\n");
                    } else {
                        out.print(processLine(trimmed, false));
                    }
                }

                for(int i=0; i<255; i++) {
                    if (byLength[i] == null) continue;
                    out.print("case " + i + ": { switch(ccSwitch"+enumSwitch+".charAt(0)) { ");
                    buildTrie("", byLength[i]);
                    out.print("}; break; }  ");
                }
                out.print("} /* switch */ ");
                if (Default != null) out.print(" " + Default);
                out.print(" } while(false); /* OUTER */\n");
                enumSwitch++;

            } else {
                out.print(processLine(s, false));
            }
        }

        return err;
    }

    private static class MyVec {
        private Object[] store;
        private int size = 0;
    
        public MyVec() { this(10); }
        public MyVec(int i) { store = new Object[i]; }
        public MyVec(int i, Object[] store) { size = i; this.store = store; }
    
        private void grow() { grow(store.length * 2); }
        private void grow(int newsize) {
            Object[] newstore = new Object[newsize];
            System.arraycopy(store, 0, newstore, 0, size);
            store = newstore;
        }

        public void removeAllElements() {
            for(int i=0; i<size; i++) store[i] = null;
            size = 0;
        }

        public void toArray(Object[] o) {
            for(int i=0; i<size; i++)
                o[i] = store[i];
        }
    
        public int indexOf(Object o) {
            for(int i=0; i<size; i++)
                if (o == null ? store[i] == null : store[i].equals(o)) return i;
        
            return -1;
        }
    
        public void addElement(Object o) {
            if (size >= store.length - 1) grow();
            store[size++] = o;
        }

        public Object peek() {
            return lastElement();
        }

        public Object elementAt(int i) {
            return store[i];
        }
    
        public Object lastElement() {
            if (size == 0) return null;
            return store[size - 1];
        }

        public void push(Object o) { addElement(o); }
        public Object pop() {
            Object ret = lastElement();
            if (size > 0) store[size--] = null;
            return ret;
        }

        public int size() { return size; }

        public void setSize(int newSize) {
            if (newSize < 0) throw new RuntimeException("tried to set size to negative value");
            if (newSize > store.length) grow(newSize * 2);
            if (newSize < size)
                for(int i=newSize; i<size; i++)
                    store[i] = null;
            size = newSize;
        }

        public void copyInto(Object[] out) {
            for(int i=0; i<size; i++)
                out[i] = store[i];
        }

        public void fromArray(Object[] in) {
            setSize(in.length);
            for(int i=0; i<size; i++)
                store[i] = in[i];
        }

        public void removeElementAt(int i) {
            if (i >= size || i < 0) throw new RuntimeException("tried to remove an element outside the vector's limits");
            for(int j=i; j<size - 1; j++)
                store[j] = store[j + 1];
            setSize(size - 1);
        }

        public void setElementAt(Object o, int i) {
            if (i >= size) setSize(i);
            store[i] = o;
        }

        public void removeElement(Object o) {
            int idx = indexOf(o);
            if (idx != -1) removeElementAt(idx);
        }

        public void insertElementAt(Object o, int at) {
            if (size == store.length) grow();
            for(int i=size; i>at; i--)
                store[i] = store[i-1];
            store[at] = o;
            size++;
        }

        public interface CompareFunc {
            public int compare(Object a, Object b);
        }

        public void sort(CompareFunc c) {
            sort(this, null, c, 0, size-1);
        }

        public static void sort(MyVec a, MyVec b, CompareFunc c) {
            if (b != null && a.size != b.size) throw new IllegalArgumentException("MyVec a and b must be of equal size");
            sort(a, b, c, 0, a.size-1);
        }

        private static final void sort(MyVec a, MyVec b, CompareFunc c, int start, int end) {
            Object tmpa, tmpb = null;
            if(start >= end) return;
            if(end-start <= 6) {
                for(int i=start+1;i<=end;i++) {
                    tmpa = a.store[i];
                    if (b != null) tmpb = b.store[i];
                    int j;
                    for(j=i-1;j>=start;j--) {
                        if(c.compare(a.store[j],tmpa) <= 0) break;
                        a.store[j+1] = a.store[j];
                        if (b != null) b.store[j+1] = b.store[j];
                    }
                    a.store[j+1] = tmpa;
                    if (b != null) b.store[j+1] = tmpb;
                }
                return;
            }

            Object pivot = a.store[end];
            int lo = start - 1;
            int hi = end;

            do {
                while(c.compare(a.store[++lo],pivot) < 0) { }
                while((hi > lo) && c.compare(a.store[--hi],pivot) > 0) { }
                swap(a, lo,hi);
                if (b != null) swap(b, lo,hi);
            } while(lo < hi);

            swap(a, lo,end);
            if (b != null) swap(b, lo,end);

            sort(a, b, c, start, lo-1);
            sort(a, b, c, lo+1, end);
        }

        private static final void swap(MyVec vec, int a, int b) {
            if(a != b) {
                Object tmp = vec.store[a];
                vec.store[a] = vec.store[b];
                vec.store[b] = tmp;
            }
        }

    }

    private void buildTrie(String prefix, Hashtable cases) {
        Enumeration caseKeys = cases.keys();
        MyVec keys = new MyVec();
        while(caseKeys.hasMoreElements()) keys.addElement(caseKeys.nextElement());
        keys.sort(new MyVec.CompareFunc() { public int compare(Object a, Object b) {
            return ((String)a).compareTo((String)b);
        } } );

        for(int i=0; i<keys.size(); i++) {
            if (!((String)keys.elementAt(i)).startsWith(prefix)) continue;
            String prefixPlusOne = ((String)keys.elementAt(i)).substring(0, prefix.length() + 1);
            if (i<keys.size()-1 && prefixPlusOne.equals((((String)keys.elementAt(i + 1)).substring(0, prefix.length() + 1)))) {
                out.print("case \'" + prefixPlusOne.charAt(prefixPlusOne.length() - 1) + "\': { ");
                out.print("switch(ccSwitch"+enumSwitch+".charAt(" + (prefix.length()+1) + ")) { ");
                buildTrie(prefixPlusOne, cases);
                out.print("} break; } ");
                while(i<keys.size() && prefixPlusOne.equals(((String)keys.elementAt(i)).substring(0, prefix.length() + 1))) i++;
                if (i<keys.size()) { i--; continue; }
            } else {
                out.print("case \'" + prefixPlusOne.charAt(prefixPlusOne.length() - 1) + "\': ");
                String code = (String)cases.get(keys.elementAt(i));
                code = code.substring(0, code.length());
                String key = (String)keys.elementAt(i);
                out.print("if (\""+key+"\".equals(ccSwitch"+enumSwitch+")) { if (true) do { " + code + " } while(false); break SUCCESS; } break;  ");
            }
        }
    }

    private String processLine(String s, boolean deleteLineEndings) throws IOException {
        if (deleteLineEndings && s.indexOf("//") != -1) s = s.substring(0, s.indexOf("//"));
        String ret = "";
        for(int i=0; i<s.length(); i++) {
            char c = s.charAt(i);
            if (!Character.isLetter(c) && !Character.isDigit(c) && c != '_') {
                ret += c;
                continue;
            }
            int j;
            for(j = i; j < s.length(); j++) {
                c = s.charAt(j);
                if (!Character.isLetter(c) && !Character.isDigit(c) && c != '_') break;
            }
            String tok = s.substring(i, j);
            Object val = replace.get(tok);
            if (val == null) {
                ret += tok;
                i = j - 1;
            } else if (val instanceof JSFunctionMacro) {
                if (s.charAt(j) != '(') { ret += tok; i = j - 1; continue; }
                ret += ((JSFunctionMacro)val).process(s.substring(j+1, s.indexOf(')', j)));
                i = s.indexOf(')', j);
            } else {
                ret += val;
                i = j - 1;
            }
        }
        if (!deleteLineEndings) ret += "\n";
        return ret;
    }

    private static int indexOfWS(String s) { return indexOfWS(s, 0); }
    private static int indexOfWS(String s, int beginIndex) {
        if (s == null || beginIndex >= s.length()) return -1;
        for (; beginIndex < s.length(); beginIndex++) {
            if (s.charAt(beginIndex) == ' ') return beginIndex;
        }
        return s.length();
    }

    private static int indexOfNotWS(String s) { return indexOfWS(s, 0); }
    private static int indexOfNotWS(String s, int beginIndex) {
        if (s == null || beginIndex >= s.length()) return -1;
        for (; beginIndex < s.length(); beginIndex++) {
            if (s.charAt(beginIndex) != ' ') return beginIndex;
        }
        return -1;
    }

    public class Warning {
        protected String msg;
        protected int line;

        public Warning() { msg = ""; }
        public Warning(String m) { msg = m; if (in != null) line = in.getLineNumber(); }

        public int getLine() { return line; }
        public String getMessage() { return msg; }
        public String toString() { return "WARNING Line "+line+": "+msg; }
    }

    public class Error extends Warning {
        public Error() { super(); }
        public Error(String m) { super(m); }
        public String toString() { return "ERROR Line "+line+": "+msg; }
    }

    public static class JSFunctionMacro {
        public String unbound1 = null;
        public String unbound2 = null;
        public String expression = null;
        public String process(String args) {
            String bound1 = null;
            String bound2 = null;
            if (unbound2 == null) {
                bound1 = args;
                return replaceAll(expression, unbound1, bound1);
            } else {
                bound1 = args.substring(0, args.indexOf(','));
                bound2 = args.substring(args.indexOf(',') + 1);
                return replaceAll(replaceAll(expression, unbound1, bound1), unbound2, bound2);
            }
        }
    }
}