// Copyright 2000-2005 the Contributors, as shown in the revision logs.
// Licensed under the GNU General Public License version 2 ("the License").
// You may not use this file except in compliance with the License.

package org.ibex.core;

import java.io.*;
import java.util.*;
import org.ibex.js.*;
import org.ibex.util.*;

/**
 *  Encapsulates a template node (the <template/> element of a
 *  .ibex file, or any child element thereof).
 *
 *  Note that the Template instance corresponding to the
 *  <template/> node carries all the header information -- hence
 *  some of the instance members are not meaningful on non-root
 *  Template instances. We refer to these non-root instances as
 *  <i>anonymous templates</i>.
 *
 *  See the Ibex reference for information on the order in which
 *  templates are applied, attributes are put, and scripts are run.
 */
public class Template {

    // Instance Members ///////////////////////////////////////////////////////

    String id = null;                   ///< the id of this box
    String redirect = null;             ///< the id of the redirect target; only meaningful on a root node
    private JS[] keys;              ///< keys to be "put" to instances of this template; elements correspond to those of vals
    private JS[] vals;                  ///< values to be "put" to instances of this template; elements correspond to those of keys
    private String[] urikeys;
    private String[] urivals;
    private Vec children = new Vec();   ///< during XML parsing, this holds the list of currently-parsed children; null otherwise
    private JS script = null;           ///< the script on this node
    Template prev;
    Template prev2;
    JS staticObject = null;


    // Only used during parsing /////////////////////////////////////////////////////////////////

    private StringBuffer content = null;   ///< during XML parsing, this holds partially-read character data; null otherwise
    private int content_start = 0;         ///< line number of the first line of <tt>content</tt>
    private int startLine = -1;            ///< the line number that this element starts on
    private Ibex ibex;


    // Static data/methods ///////////////////////////////////////////////////////////////////

    // for non-root nodes
    private Template(Template t, int startLine) { prev = t; this.ibex = t.ibex; this.startLine = startLine; }
    private Template(Ibex ibex) { this.ibex = ibex; }
    

    // Methods to apply templates ////////////////////////////////////////////////////////

   
    /** Applies the template to Box b
     *  @param pboxes a vector of all box parents on which to put $-references
     *  @param ptemplates a vector of the fileNames to recieve private references on the pboxes
     */
    public void apply(Box b) throws JSExn {
        try {
            apply(b, null);
        } catch (IOException e) {
            b.clear(Box.VISIBLE);
            b.RECONSTRAIN();
            Log.warn(this, e);
            throw new JSExn(e.toString());
        } catch (JSExn e) {
            b.clear(Box.VISIBLE);
            b.RECONSTRAIN();
            Log.warn(this, e);
            throw e;
        }
    }

    private static final JS[] callempty = new JS[0];
    private void apply(Box b, PerInstantiationScope parentPis) throws JSExn, IOException {
        if (prev != null) prev.apply(b, null);
        if (prev2 != null) prev2.apply(b, null);

        // FIXME this dollar stuff is all wrong
        if (id != null) parentPis.putDollar(id, b);

        PerInstantiationScope pis = new PerInstantiationScope(b, ibex, parentPis, staticObject);
        for(int i=0; i<urikeys.length; i++) {
            if (urikeys[i] == null) continue;
            // FEATURE: Cache urikeys and resolved resources
            //pis.declare(JSU.S(urikeys[i]));
            // JS:FIXME: ugly
            pis.sput(JSU.S(urikeys[i]), ibex.resolveString(urivals[i], true));
        }

        // FIXME needs to obey the new application-ordering rules
        for (int i=0; children != null && i<children.size(); i++) {
            Box kid = new Box();
            ((Template)children.elementAt(i)).apply(kid, pis);
            b.putAndTriggerTraps(b.get(JSU.S("numchildren")), kid);
        }

        if (script != null) JSU.cloneWithNewGlobalScope(script, pis).call(null, callempty);

        for(int i=0; keys != null && i < keys.length; i++) {
            if (keys[i] == null) continue;
            JS key = keys[i];
            JS val = vals[i];

            if ("null".equals(val)) val = null;

            if (JSU.isString(val) && (JSU.toString(val).length() > 0)) {
                switch (JSU.toString(val).charAt(0)) {
                    case '$':
                        val = pis.get(val);
                        if (val == null) throw new JSExn("unknown box id '"+JSU.str(vals[i])+"' referenced in XML attribute");
                        break;
                    case '.':
                        val = ibex.resolveString(JSU.toString(val).substring(1), false);
                    // FIXME: url case
                    // FIXME: should we be resolving all of these in the XML-parsing code?
                }
            }
            b.putAndTriggerTraps(key, val);
        }
    }



    // XML Parsing /////////////////////////////////////////////////////////////////

    public static Template buildTemplate(String sourceName, JS s, Ibex ibex) {
        try {
            return new TemplateHelper(sourceName, s, ibex).t;
        } catch (Exception e) {
            Log.error(Template.class, e);
            return null;
        }
    }

    /** handles XML parsing; builds a Template tree as it goes */
    static final class TemplateHelper extends XML {

        String sourceName;
        private int state = STATE_INITIAL;
        private static final int STATE_INITIAL = 0;
        private static final int STATE_IN_ROOT_NODE = 1;
        private static final int STATE_IN_TEMPLATE_NODE = 2; 
        private static final int STATE_IN_META_NODE = 3;
        private static final JS[] callempty = new JS[0];

        StringBuffer static_content = null;
        int static_content_start = 0;
        Vec nodeStack = new Vec();
        Template t = null;
        int meta = 0;
        Ibex ibex;

        String initial_uri = "";

        public TemplateHelper(String sourceName, JS s, Ibex ibex) throws XML.Exn, IOException, JSExn {
            this.sourceName = sourceName;
            this.ibex = ibex;
            InputStream is = JSU.getInputStream(s);
            Ibex.Blessing b = Ibex.Blessing.getBlessing(s).parent;
            while(b != null) {
                if(b.parentkey != null) initial_uri = JSU.toString(b.parentkey) + (initial_uri.equals("") ? "" : "." + initial_uri);
                b = b.parent;
            }
            initial_uri = "";
            parse(new InputStreamReader(is));
            JS staticScript = parseScript(static_content, static_content_start);
            t.staticObject = new JS.Obj();
            JS staticScope = new PerInstantiationScope(null, ibex, null, t.staticObject);
            if (staticScript != null) JSU.cloneWithNewGlobalScope(staticScript, staticScope).call(null, callempty);
        }

        private JS parseScript(StringBuffer content, int content_start) throws IOException {
            if (content == null) return null;
            String contentString = content.toString();
            if (contentString.trim().length() > 0) return JSU.fromReader(sourceName, content_start, new StringReader(contentString));
            return null;
        }

        public void startElement(Tree.Element c) throws XML.Exn {
            Tree.Attributes a = c.getAttributes();
            switch(state) {
                case STATE_IN_META_NODE: { meta++; return; }
                case STATE_INITIAL:
                    if (!"ibex".equals(c.getLocalName()))
                        throw new XML.Exn("root element was not <ibex>", XML.Exn.SCHEMA, getLine(), getCol());
                    if (a.attrSize() != 0)
                        throw new XML.Exn("root element must not have attributes", XML.Exn.SCHEMA, getLine(), getCol());
                    state = STATE_IN_ROOT_NODE;
                    return;
                case STATE_IN_ROOT_NODE:
                    if ("ibex://meta".equals(c.getUri())) { state = STATE_IN_META_NODE; meta = 0; return; }
                    state = STATE_IN_TEMPLATE_NODE;
                    t = (t == null) ? new Template(ibex) : new Template(t, getLine());
                    break;
                case STATE_IN_TEMPLATE_NODE:
                    nodeStack.addElement(t);
                    t = new Template(ibex);
                    break;
            }

            // FIXME: This is all wrong
            if (!("ibex://ui".equals(c.getUri()) && "box".equals(c.getLocalName()))) {
                String tagname = (c.getUri() == null || "".equals(c.getUri()) ? "" :
                                 (c.getUri() + ".")) + c.getLocalName();
                // GROSS hack
                try {
                    // GROSSER hack
                    // t.prev2 = (Template)t.ibex.resolveString(tagname, false).call(null, null, null, null, 9999);
                    if(t.prev2 != null) throw new Error("FIXME: t.prev2 != null");
                    t.prev2 = ((Ibex.Blessing)t.ibex.resolveString(tagname, false)).getTemplate();
                    if(t.prev2 == null) throw new Exception("" + tagname + " not found");
                } catch (Exception e) {
                    Log.error(Template.class, e);
                }
            }

            Tree.Prefixes prefixes = c.getPrefixes();
            t.urikeys = new String[prefixes.pfxSize()];
            t.urivals = new String[prefixes.pfxSize()];

            int ii = 0;
            for (int i=0; i < prefixes.pfxSize(); i++) {
                String key = prefixes.getPrefixKey(i);
                String val = prefixes.getPrefixVal(i);
                if (val.equals("ibex://ui")) continue;
                if (val.equals("ibex://meta")) continue;
                t.urikeys[ii] = key;
                if (val.length() > 0 && val.charAt(0) == '.') val = val.substring(1);
                t.urivals[ii] = val;
                ii++;
            }

            // FIXME: 2-value Array
            Basket.Array keys = new Basket.Array(a.attrSize());
            Basket.Array vals = new Basket.Array(a.attrSize());

            // process attributes into Vecs, dealing with any XML Namespaces in the process
            ATTR: for (int i=0; i < a.attrSize(); i++) {
                if (a.getKey(i).equals("id")) {
                    t.id = a.getVal(i).toString().intern();
                    continue ATTR;
                }

                // treat value starting with '.' as resource reference
                String uri = a.getUri(i); if (uri != null && !uri.equals("")) uri = '.' + uri;
                keys.add(a.getKey(i));
                vals.add((a.getVal(i).startsWith(".") ? uri : "") + a.getVal(i));
            }

            if (keys.size() == 0) return;

            // sort the attributes lexicographically
            Basket.Array.sort(keys, vals, new Basket.CompareFunc() {
                public int compare(Object a, Object b) { return ((String)a).compareTo((String)b); }
            }, 0, keys.size() - 1);

            t.keys = new JS[keys.size()];
            t.vals = new JS[vals.size()];
            
            // convert attributes to appropriate types and intern strings
            for(int i=0; i<t.keys.length; i++) {
                // FEATURE: Intern
                t.keys[i] = JSU.S((String)keys.get(i));
                String valString = (String) vals.get(i);
                
                if (valString.equals("true")) t.vals[i] = JSU.T;
                else if (valString.equals("false")) t.vals[i] = JSU.F;
                else if (valString.equals("null")) t.vals[i] = null;
                else {
                    boolean hasNonNumeral = false;
                    boolean periodUsed = false;
                    for(int j=0; j<valString.length(); j++)
                        if (j == 0 && valString.charAt(j) == '-') {
                        } else if (valString.charAt(j) == '.' && !periodUsed && j != valString.length() - 1) {
                            periodUsed = true;
                        } else if (!Character.isDigit(valString.charAt(j))) {
                            hasNonNumeral = true;
                            break;
                        }
                    if (valString.length() > 0 && !hasNonNumeral) t.vals[i] = JSU.N(Double.parseDouble((valString)));
                    else t.vals[i] = JSU.S(valString.intern()); // FEATURE: JS.intern() ?
                }
            }
        }

        public void endElement(Tree.Element c) throws XML.Exn, IOException {
            switch(state) {
                case STATE_IN_META_NODE: if (--meta < 0) state = STATE_IN_ROOT_NODE; return;
                case STATE_IN_ROOT_NODE: return;
                case STATE_IN_TEMPLATE_NODE: {
                    if (t.content != null) { t.script = parseScript(t.content, t.content_start); t.content = null; }
                    if (nodeStack.size() == 0) { state = STATE_IN_ROOT_NODE; return; }
                    Template oldt = t;
                    t = (Template)nodeStack.lastElement();
                    nodeStack.setSize(nodeStack.size() - 1);
                    t.children.addElement(oldt);
                    int oldt_lines = getLine() - oldt.startLine;
                    if (t.content == null) t.content = new StringBuffer();
                    for (int i=0; oldt_lines > i; i++) t.content.append('\n');
                }
            }
        }

        public void characters(char[] ch, int start, int length) throws XML.Exn {
            for (int i=0; length >i; i++) if (ch[start+i] == '\t')
                Log.error(Template.class, "tabs are not allowed in Ibex files ("+getLine()+":"+getCol()+")");
            switch(state) {
                case STATE_IN_TEMPLATE_NODE:
                    if (t.content == null) {
                        t.content_start = getLine();
                        t.content = new StringBuffer();
                    }
                    t.content.append(ch, start, length);
                    return;
                case STATE_IN_ROOT_NODE:
                    if (static_content == null) {
                        static_content_start = getLine();
                        static_content = new StringBuffer();
                    }
                    static_content.append(ch, start, length);
                    return;
            }
        }

        public void whitespace(char[] ch, int start, int length) throws XML.Exn { }
    }

    // FIXME: david, get to work
    private static class PerInstantiationScope extends JS.Obj {
        Ibex ibex = null;
        PerInstantiationScope parentBoxPis = null;
        JS myStatic = null;
        JS box;
        void putDollar(String key, Box target) throws JSExn {
            if (parentBoxPis != null) parentBoxPis.putDollar(key, target);
            JS jskey = JSU.S("$" + key);
            //declare(jskey);
            sput(jskey, target);
        }
        // JS:FIXME: ugly
        void sput(JS key, JS val) throws JSExn { super.put(key,val); }
        public PerInstantiationScope(JS box, Ibex ibex, PerInstantiationScope parentBoxPis, JS myStatic) {
            this.parentBoxPis = parentBoxPis;
            this.ibex = ibex;
            this.myStatic = myStatic;
            this.box = box;
        }
        public JS get(JS key) throws JSExn {
            if(JSU.isString(key)) {
                String s = JSU.toString(key);
                // JS:FIXME This is a hack
                if (super.get(key) != null) return super.get(key);
                if (s.equals("ibex")) return ibex;
                if (s.equals("")) return ibex.get(key);
                if (s.equals("static")) return myStatic;
            }
            // JS:FIXME: This won't work with traps that do blocking operations
            return box.getAndTriggerTraps(key);
        }
        // JS:FIXME: Everything below here should come from js.scope or something
        public void put(JS key, JS val) throws JSExn { if(box != null) box.putAndTriggerTraps(key,val); else super.put(key,val); }
        public void addTrap(JS key, JS f) throws JSExn { box.addTrap(key,f); }
        public void delTrap(JS key, JS f) throws JSExn { box.delTrap(key,f); }
    }

}