/*
 * [The "BSD license"]
 *  Copyright (c) 2011 Terence Parr
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *  3. The name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 *  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 *  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 *  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.stringtemplate.v4;

import org.stringtemplate.v4.compiler.CompiledST;
import org.stringtemplate.v4.compiler.FormalArgument;
import org.stringtemplate.v4.debug.AddAttributeEvent;
import org.stringtemplate.v4.debug.ConstructionEvent;
import org.stringtemplate.v4.debug.EvalTemplateEvent;
import org.stringtemplate.v4.debug.InterpEvent;
import org.stringtemplate.v4.gui.STViz;
import org.stringtemplate.v4.misc.Aggregate;
import org.stringtemplate.v4.misc.ErrorBuffer;
import org.stringtemplate.v4.misc.ErrorManager;
import org.stringtemplate.v4.misc.MultiMap;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.StringWriter;
import java.io.Writer;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;

An instance of the StringTemplate. It consists primarily of a reference to its implementation (shared among all instances) and a hash table of attributes. Because of dynamic scoping, we also need a reference to any enclosing instance. For example, in a deeply nested template for an HTML page body, we could still reference the title attribute defined in the outermost page template. 
 To use templates, you create one (usually via STGroup) and then inject attributes using add. To render its attacks, use render().
 TODO: locals is not actually a hash table like the documentation says.
/** An instance of the StringTemplate. It consists primarily of
 *  a {@linkplain ST#impl reference} to its implementation (shared among all
 *  instances) and a hash table of {@linkplain ST#locals attributes}.  Because
 *  of dynamic scoping, we also need a reference to any enclosing instance. For
 *  example, in a deeply nested template for an HTML page body, we could still
 *  reference the title attribute defined in the outermost page template.
 * <p>
 *  To use templates, you create one (usually via {@link STGroup}) and then inject
 *  attributes using {@link #add}. To render its attacks, use {@link ST#render()}.</p>
 * <p>
 *  TODO: {@link ST#locals} is not actually a hash table like the documentation
 *  says.</p>
 */
public class ST {
	public final static String VERSION = "4.1";

	
<@r()>, <@r>...<@end>, and @t.r() ::= "..." defined manually by coder /** {@code <@r()>}, {@code <@r>...<@end>}, and {@code @t.r() ::= "..."} defined manually by coder */
    public enum RegionType {
		
<@r()> /** {@code <@r()>} */
		IMPLICIT,
		
<@r>...<@end> /** {@code <@r>...<@end>} */
		EMBEDDED,
		
@t.r() ::= "..." /** {@code @t.r() ::= "..."} */
		EXPLICIT
	}

	
Events during template hierarchy construction (not evaluation) /** Events during template hierarchy construction (not evaluation) */
	public static class DebugState {
		
Record who made us? ConstructionEvent creates Exception to grab stack /** Record who made us? {@link ConstructionEvent} creates {@link Exception} to grab stack */
		public ConstructionEvent newSTEvent;

		
Track construction-time add attribute "events"; used for ST user-level debugging /** Track construction-time add attribute "events"; used for ST user-level debugging */
		public MultiMap<String, AddAttributeEvent> addAttrEvents = new MultiMap<String, AddAttributeEvent>();
	}

    public static final String UNKNOWN_NAME = "anonymous";
	public static final Object EMPTY_ATTR = new Object();

	
When there are no formal args for template t and you map t across
 some values, t implicitly gets arg "it".  E.g., "$it$"
/** When there are no formal args for template t and you map t across
	 *  some values, t implicitly gets arg "it".  E.g., "<b>$it$</b>"
	 */
	public static final String IMPLICIT_ARG_NAME = "it";

    
The implementation for this template among all instances of same template . /** The implementation for this template among all instances of same template . */
    public CompiledST impl;

	
Safe to simultaneously write via add, which is synchronized. Reading during exec is, however, NOT synchronized. So, not thread safe to add attributes while it is being evaluated. Initialized to EMPTY_ATTR to distinguish null from empty. /** Safe to simultaneously write via {@link #add}, which is synchronized.
	 *  Reading during exec is, however, NOT synchronized.  So, not thread safe
	 *  to add attributes while it is being evaluated.  Initialized to
	 *  {@link #EMPTY_ATTR} to distinguish {@code null} from empty.
	 */
	protected Object[] locals;

    
Created as instance of which group? We need this to initialize interpreter
 via render.  So, we create st and then it needs to know which
 group created it for sake of polymorphism:
 
 st = skin1.getInstanceOf("searchbox");
 result = st.render(); // knows skin1 created it
 
 Say we have a group g1 with template t that imports templates t and u from another group g2. g1.getInstanceOf("u") finds u in g2 but remembers that g1 created it. If u includes t, it should create g1.t not g2.t. 
  g1 = {t(), u()}
  |
  v
  g2 = {t()}
 
/** Created as instance of which group? We need this to initialize interpreter
     *  via render.  So, we create st and then it needs to know which
     *  group created it for sake of polymorphism:
     *
	 *  <pre>
     *  st = skin1.getInstanceOf("searchbox");
     *  result = st.render(); // knows skin1 created it
	 *  </pre>
	 *
	 *  Say we have a group {@code g1} with template {@code t} that imports
	 *  templates {@code t} and {@code u} from another group {@code g2}.
	 *  {@code g1.getInstanceOf("u")} finds {@code u} in {@code g2} but remembers
	 *  that {@code g1} created it.  If {@code u} includes {@code t}, it should
	 *  create {@code g1.t} not {@code g2.t}.
	 *
	 *  <pre>
	 *   g1 = {t(), u()}
	 *   |
	 *   v
	 *   g2 = {t()}
	 *  </pre>
     */
    public STGroup groupThatCreatedThisInstance;

	
If STGroup.trackCreationEvents, track creation and add attribute events for each object. Create this object on first use. /** If {@link STGroup#trackCreationEvents}, track creation and add
	 *  attribute events for each object. Create this object on first use.
	 */
	public DebugState debugState;

	
Just an alias for ArrayList, but this way I can track whether a list is something ST created or it's an incoming list. /** Just an alias for {@link ArrayList}, but this way I can track whether a
     *  list is something ST created or it's an incoming list.
     */
    public static final class AttributeList extends ArrayList<Object> {
        public AttributeList(int size) { super(size); }
        public AttributeList() { super(); }
    }

	
Used by group creation routine, not by users /** Used by group creation routine, not by users */
    protected ST() {
		if ( STGroup.trackCreationEvents ) {
			if ( debugState==null ) debugState = new ST.DebugState();
			debugState.newSTEvent = new ConstructionEvent();
		}
	}

	
Used to make templates inline in code for simple things like SQL or log records.
 No formal arguments are set and there is no enclosing instance.
/** Used to make templates inline in code for simple things like SQL or log records.
	 *  No formal arguments are set and there is no enclosing instance.
	 */
    public ST(String template) {
        this(STGroup.defaultGroup, template);
    }

    
Create ST using non-default delimiters; each one of these will live in it's own group since you're overriding a default; don't want to alter STGroup.defaultGroup. /** Create ST using non-default delimiters; each one of these will live
     *  in it's own group since you're overriding a default; don't want to
     *  alter {@link STGroup#defaultGroup}.
     */
    public ST(String template, char delimiterStartChar, char delimiterStopChar) {
        this(new STGroup(delimiterStartChar, delimiterStopChar), template);
    }

    public ST(STGroup group, String template) {
		this();
		groupThatCreatedThisInstance = group;
		impl = groupThatCreatedThisInstance.compile(group.getFileName(), null,
													null, template, null);
		impl.hasFormalArgs = false;
		impl.name = UNKNOWN_NAME;
		impl.defineImplicitlyDefinedTemplates(groupThatCreatedThisInstance);
    }

	
Clone a prototype template. Copy all fields minus debugState; don't delegate to ST(), which creates ConstructionEvent. /** Clone a prototype template.
	 *  Copy all fields minus {@link #debugState}; don't delegate to {@link #ST()},
	 *  which creates {@link ConstructionEvent}.
	 */
	public ST(ST proto) {
		try {
			// Because add() can fake a formal arg def, make sure to clone impl
			// entire impl so formalArguments list is cloned as well. Don't want
			// further derivations altering previous arg defs. See
			// testRedefOfKeyInCloneAfterAddingAttribute().
			this.impl = proto.impl.clone();
		}
		catch (CloneNotSupportedException e) {
			throw new RuntimeException(e);
		}
		if ( proto.locals!=null ) {
			this.locals = new Object[proto.locals.length];
			System.arraycopy(proto.locals, 0, this.locals, 0, proto.locals.length);
		}
		else if (impl.formalArguments != null && !impl.formalArguments.isEmpty()) {
			this.locals = new Object[impl.formalArguments.size()];
			Arrays.fill(this.locals, EMPTY_ATTR);
		}
		this.groupThatCreatedThisInstance = proto.groupThatCreatedThisInstance;
	}

	
Inject an attribute (name/value pair). If there is already an attribute with that name, this method turns the attribute into an AttributeList with both the previous and the new attribute as elements. This method will never alter a List that you inject. If you send in a List and then inject a single value element, add copies original list and adds the new value. The attribute name cannot be null or contain '.'. 
 Return this so we can chain:
 
 t.add("x", 1).add("y", "hi")
/** Inject an attribute (name/value pair). If there is already an attribute
	 *  with that name, this method turns the attribute into an
	 *  {@link AttributeList} with both the previous and the new attribute as
	 *  elements. This method will never alter a {@link List} that you inject.
	 *  If you send in a {@link List} and then inject a single value element,
	 *  {@code add} copies original list and adds the new value. The
	 *  attribute name cannot be null or contain '.'.
	 *  <p>
	 *  Return {@code this} so we can chain:</p>
	 *  <p>
	 *  {@code t.add("x", 1).add("y", "hi")}</p>
     */
    public synchronized ST add(String name, Object value) {
		if ( name==null ) {
			throw new NullPointerException("null attribute name");
		}
		if ( name.indexOf('.')>=0 ) {
			throw new IllegalArgumentException("cannot have '.' in attribute names");
		}

		if ( STGroup.trackCreationEvents ) {
			if ( debugState==null ) debugState = new ST.DebugState();
			debugState.addAttrEvents.map(name, new AddAttributeEvent(name, value));
		}

		FormalArgument arg = null;
		if ( impl.hasFormalArgs ) {
			if ( impl.formalArguments!=null ) arg = impl.formalArguments.get(name);
			if ( arg==null ) {
				throw new IllegalArgumentException("no such attribute: "+name);
			}
		}
		else {
			// define and make room in locals (a hack to make new ST("simple template") work.)
			if ( impl.formalArguments!=null ) {
				arg = impl.formalArguments.get(name);
			}
			if ( arg==null ) { // not defined
				arg = new FormalArgument(name);
				impl.addArg(arg);
				if ( locals==null ) locals = new Object[1];
				else {
					Object[] copy = new Object[impl.formalArguments.size()];
					System.arraycopy(locals, 0, copy, 0,
									 Math.min(locals.length, impl.formalArguments.size()));
					locals = copy;
				}
				locals[arg.index] = EMPTY_ATTR;
			}
		}

		Object curvalue = locals[arg.index];
        if ( curvalue==EMPTY_ATTR ) { // new attribute
			locals[arg.index] = value;
            return this;
        }

        // attribute will be multi-valued for sure now
        // convert current attribute to list if not already
        // copy-on-write semantics; copy a list injected by user to add new value
        AttributeList multi = convertToAttributeList(curvalue);
		locals[arg.index] = multi; // replace with list

        // now, add incoming value to multi-valued attribute
        if ( value instanceof List ) {
            // flatten incoming list into existing list
            multi.addAll((List<?>)value);
        }
        else if ( value!=null && value.getClass().isArray() ) {
			if (value instanceof Object[]) {
				multi.addAll(Arrays.asList((Object[])value));
			}
			else {
				multi.addAll(convertToAttributeList(value));
			}
        }
        else {
            multi.add(value);
        }
		return this;
    }

	
Split aggrName.{propName1,propName2} into list [propName1, propName2] and the aggrName. Spaces are allowed around ','. /** Split {@code aggrName.{propName1,propName2}} into list
	 *  {@code [propName1, propName2]} and the {@code aggrName}. Spaces are
	 *  allowed around {@code ','}.
	 */
	public synchronized ST addAggr(String aggrSpec, Object... values) {
		int dot = aggrSpec.indexOf(".{");
		if ( values==null || values.length==0 ) {
			throw new IllegalArgumentException("missing values for aggregate attribute format: "+
											   aggrSpec);
		}
		int finalCurly = aggrSpec.indexOf('}');
		if ( dot<0 || finalCurly < 0 ) {
			throw new IllegalArgumentException("invalid aggregate attribute format: "+
											   aggrSpec);
		}
		String aggrName = aggrSpec.substring(0, dot);
		String propString = aggrSpec.substring(dot+2, aggrSpec.length()-1);
		propString = propString.trim();
		String[] propNames = propString.split("\\ *,\\ *");
		if ( propNames==null || propNames.length==0 ) {
			throw new IllegalArgumentException("invalid aggregate attribute format: "+
											   aggrSpec);
		}
		if ( values.length != propNames.length ) {
			throw new IllegalArgumentException(
				"number of properties and values mismatch for aggregate attribute format: "+
				aggrSpec);
		}
		int i=0;
		Aggregate aggr = new Aggregate();
		for (String p : propNames) {
			Object v = values[i++];
			aggr.properties.put(p, v);
		}

		add(aggrName, aggr); // now add as usual
		return this;
	}

	
Remove an attribute value entirely (can't remove attribute definitions). /** Remove an attribute value entirely (can't remove attribute definitions). */
	public void remove(String name) {
		if ( impl.formalArguments==null ) {
			if ( impl.hasFormalArgs ) {
				throw new IllegalArgumentException("no such attribute: "+name);
			}
			return;
		}
		FormalArgument arg = impl.formalArguments.get(name);
		if ( arg==null ) {
			throw new IllegalArgumentException("no such attribute: "+name);
		}
		locals[arg.index] = EMPTY_ATTR; // reset value
	}

	
Set locals attribute value when you only know the name, not the index. This is ultimately invoked by calling ST#add from outside so toss an exception to notify them. /** Set {@code locals} attribute value when you only know the name, not the
	 *  index. This is ultimately invoked by calling {@code ST#add} from
	 *  outside so toss an exception to notify them.
	 */
    protected void rawSetAttribute(String name, Object value) {
		if ( impl.formalArguments==null ) {
			throw new IllegalArgumentException("no such attribute: "+name);
		}
		FormalArgument arg = impl.formalArguments.get(name);
		if ( arg==null ) {
			throw new IllegalArgumentException("no such attribute: "+name);
		}
		locals[arg.index] = value;
	}

	
Find an attribute in this template only. /** Find an attribute in this template only. */
	public Object getAttribute(String name) {
		FormalArgument localArg = null;
		if ( impl.formalArguments!=null ) localArg = impl.formalArguments.get(name);
		if ( localArg!=null ) {
			Object o = locals[localArg.index];
			if ( o==ST.EMPTY_ATTR ) o = null;
			return o;
		}
		return null;
	}

    public Map<String, Object> getAttributes() {
		if ( impl.formalArguments==null ) return null;
		Map<String, Object> attributes = new HashMap<String, Object>();
		for (FormalArgument a : impl.formalArguments.values()) {
			Object o = locals[a.index];
			if ( o==ST.EMPTY_ATTR ) o = null;
			attributes.put(a.name, o);
		}
		return attributes;
	}

    protected static AttributeList convertToAttributeList(Object curvalue) {
        AttributeList multi;
        if ( curvalue == null ) {
            multi = new AttributeList(); // make list to hold multiple values
            multi.add(curvalue);                 // add previous single-valued attribute
        }
        else if ( curvalue instanceof AttributeList ) { // already a list made by ST
            multi = (AttributeList)curvalue;
        }
        else if ( curvalue instanceof List) { // existing attribute is non-ST List
            // must copy to an ST-managed list before adding new attribute
            // (can't alter incoming attributes)
            List<?> listAttr = (List<?>)curvalue;
            multi = new AttributeList(listAttr.size());
            multi.addAll(listAttr);
        }
        else if ( curvalue instanceof Object[] ) { // copy array to list
            Object[] a = (Object[])curvalue;
            multi = new AttributeList(a.length);
            multi.addAll(Arrays.asList(a)); // asList doesn't copy as far as I can tell
        }
        else if ( curvalue.getClass().isArray() ) { // copy primitive array to list
			int length = Array.getLength(curvalue);
            multi = new AttributeList(length);
			for (int i = 0; i < length; i++) {
				multi.add(Array.get(curvalue, i));
			}
        }
        else {
            // curvalue nonlist and we want to add an attribute
            // must convert curvalue existing to list
            multi = new AttributeList(); // make list to hold multiple values
            multi.add(curvalue);                 // add previous single-valued attribute
        }
        return multi;
    }

    public String getName() { return impl.name; }

	public boolean isAnonSubtemplate() { return impl.isAnonSubtemplate; }

	public int write(STWriter out) throws IOException {
		Interpreter interp = new Interpreter(groupThatCreatedThisInstance,
											 impl.nativeGroup.errMgr,
											 false);
		InstanceScope scope = new InstanceScope(null, this);
		return interp.exec(out, scope);
    }

	public int write(STWriter out, Locale locale) {
		Interpreter interp = new Interpreter(groupThatCreatedThisInstance,
											 locale,
											 impl.nativeGroup.errMgr,
											 false);
		InstanceScope scope = new InstanceScope(null, this);
		return interp.exec(out, scope);
	}

	public int write(STWriter out, STErrorListener listener) {
		Interpreter interp = new Interpreter(groupThatCreatedThisInstance,
											 new ErrorManager(listener),
											 false);
		InstanceScope scope = new InstanceScope(null, this);
		return interp.exec(out, scope);
	}

	public int write(STWriter out, Locale locale, STErrorListener listener) {
		Interpreter interp = new Interpreter(groupThatCreatedThisInstance,
											 locale,
											 new ErrorManager(listener),
											 false);
		InstanceScope scope = new InstanceScope(null, this);
		return interp.exec(out, scope);
	}

	public int write(File outputFile, STErrorListener listener) throws IOException {
		return write(outputFile, listener, "UTF-8", Locale.getDefault(), STWriter.NO_WRAP);
	}

	public int write(File outputFile, STErrorListener listener, String encoding)
		throws IOException
	{
		return write(outputFile, listener, encoding, Locale.getDefault(), STWriter.NO_WRAP);
	}

	public int write(File outputFile, STErrorListener listener, String encoding, int lineWidth)
		throws IOException
	{
		return write(outputFile, listener, encoding, Locale.getDefault(), lineWidth);
	}

	public int write(File outputFile,
					 STErrorListener listener,
					 String encoding,
					 Locale locale,
					 int lineWidth)
		throws IOException
	{
		Writer bw = null;
		try {
			FileOutputStream fos = new FileOutputStream(outputFile);
			OutputStreamWriter osw = new OutputStreamWriter(fos, encoding);
			bw = new BufferedWriter(osw);
			AutoIndentWriter w = new AutoIndentWriter(bw);
			w.setLineWidth(lineWidth);
			int n = write(w, locale, listener);
			bw.close();
			bw = null;
			return n;
		}
		finally {
			if (bw != null) bw.close();
		}
	}

	public String render() { return render(Locale.getDefault()); }

    public String render(int lineWidth) { return render(Locale.getDefault(), lineWidth); }

    public String render(Locale locale) { return render(locale, STWriter.NO_WRAP); }

    public String render(Locale locale, int lineWidth) {
        StringWriter out = new StringWriter();
        STWriter wr = new AutoIndentWriter(out);
        wr.setLineWidth(lineWidth);
        write(wr, locale);
        return out.toString();
    }

	// LAUNCH A WINDOW TO INSPECT TEMPLATE HIERARCHY

    public STViz inspect() { return inspect(Locale.getDefault()); }

    public STViz inspect(int lineWidth) {
		return inspect(impl.nativeGroup.errMgr, Locale.getDefault(), lineWidth);
	}

    public STViz inspect(Locale locale) {
		return inspect(impl.nativeGroup.errMgr, locale, STWriter.NO_WRAP);
	}

	public STViz inspect(ErrorManager errMgr, Locale locale, int lineWidth) {
		ErrorBuffer errors = new ErrorBuffer();
		impl.nativeGroup.setListener(errors);
		StringWriter out = new StringWriter();
		STWriter wr = new AutoIndentWriter(out);
		wr.setLineWidth(lineWidth);
		Interpreter interp =
			new Interpreter(groupThatCreatedThisInstance, locale, true);
		InstanceScope scope = new InstanceScope(null, this);
		interp.exec(wr, scope); // render and track events
		List<InterpEvent> events = interp.getEvents();
		EvalTemplateEvent overallTemplateEval =
			(EvalTemplateEvent)events.get(events.size()-1);
		STViz viz = new STViz(errMgr, overallTemplateEval, out.toString(), interp,
							  interp.getExecutionTrace(), errors.errors);
		viz.open();
		return viz;
	}

	// TESTING SUPPORT

	public List<InterpEvent> getEvents() { return getEvents(Locale.getDefault()); }

    public List<InterpEvent> getEvents(int lineWidth) { return getEvents(Locale.getDefault(), lineWidth); }

    public List<InterpEvent> getEvents(Locale locale) { return getEvents(locale, STWriter.NO_WRAP); }

    public List<InterpEvent> getEvents(Locale locale, int lineWidth) {
        StringWriter out = new StringWriter();
        STWriter wr = new AutoIndentWriter(out);
        wr.setLineWidth(lineWidth);
        Interpreter interp =
			new Interpreter(groupThatCreatedThisInstance, locale, true);
		InstanceScope scope = new InstanceScope(null, this);
        interp.exec(wr, scope); // render and track events
        return interp.getEvents();
    }

	@Override
    public String toString() {
        if ( impl==null ) return "bad-template()";
		String name = impl.name+"()";
		if (this.impl.isRegion) {
			name = "@" + STGroup.getUnMangledTemplateName(name);
		}

        return name;
    }

	
ST.format("<%1>:<%2>", n, p);

/**
	 * <pre>
	 * ST.format("&lt;%1&gt;:&lt;%2&gt;", n, p);
	 * </pre>
	 */
	public static String format(String template, Object... attributes) {
		return format(STWriter.NO_WRAP, template, attributes);
	}

	public static String format(int lineWidth, String template, Object... attributes) {
		template = template.replaceAll("%([0-9]+)", "arg$1");
		ST st = new ST(template);
		int i = 1;
		for (Object a : attributes) {
			st.add("arg"+i, a);
			i++;
		}
		return st.render(lineWidth);
	}
}