/*
 * $Id: JavascriptValidatorTag.java 383908 2006-03-07 15:33:42Z niallp $ 
 *
 * Copyright 2001-2005 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.struts.taglib.html;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.StringTokenizer;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.BodyTagSupport;

import org.apache.commons.validator.Field;
import org.apache.commons.validator.Form;
import org.apache.commons.validator.ValidatorAction;
import org.apache.commons.validator.ValidatorResources;
import org.apache.commons.validator.Var;
import org.apache.commons.validator.util.ValidatorUtils;
import org.apache.struts.Globals;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.config.ModuleConfig;
import org.apache.struts.taglib.TagUtils;
import org.apache.struts.util.MessageResources;
import org.apache.struts.validator.Resources;
import org.apache.struts.validator.ValidatorPlugIn;

/**
 * Custom tag that generates JavaScript for client side validation based
 * on the validation rules loaded by the <code>ValidatorPlugIn</code>
 * defined in the struts-config.xml file.
 *
 * @version $Rev: 383908 $ $Date: 2006-03-07 15:33:42 +0000 (Tue, 07 Mar 2006) $
 * @since Struts 1.1
 */
public class JavascriptValidatorTag extends BodyTagSupport {

    /**
     * A Comparator to use when sorting ValidatorAction objects.
     */
    private static final Comparator actionComparator = new Comparator() {
        public int compare(Object o1, Object o2) {

            ValidatorAction va1 = (ValidatorAction) o1;
            ValidatorAction va2 = (ValidatorAction) o2;

            if ((va1.getDepends() == null || va1.getDepends().length() == 0)
                && (va2.getDepends() == null || va2.getDepends().length() == 0)) {
                return 0;

            } else if (
                (va1.getDepends() != null && va1.getDepends().length() > 0)
                    && (va2.getDepends() == null || va2.getDepends().length() == 0)) {
                return 1;

            } else if (
                (va1.getDepends() == null || va1.getDepends().length() == 0)
                    && (va2.getDepends() != null && va2.getDepends().length() > 0)) {
                return -1;

            } else {
                return va1.getDependencyList().size() - va2.getDependencyList().size();
            }
        }
    };

    /**
     * The start of the HTML comment hiding JavaScript from old browsers.
     * @since Struts 1.2
     */
    protected static final String HTML_BEGIN_COMMENT = "\n<!-- Begin \n";

    /**
     * The end of the HTML comment hiding JavaScript from old browsers.
     * @since Struts 1.2
     */
    protected static final String HTML_END_COMMENT = "//End --> \n";

    // ----------------------------------------------------------- Properties

    /**
     * The servlet context attribute key for our resources.
     */
    protected String bundle = Globals.MESSAGES_KEY;

    /**
     * The default locale on our server.
     * @deprecated This variable is no longer used.
     */
    protected static Locale defaultLocale = Locale.getDefault();

    /**
     * The name of the form that corresponds with the action name
     * in struts-config.xml. Specifying a form name places a
     * &lt;script&gt; &lt;/script&gt; around the javascript.
     */
    protected String formName = null;
    
    /**
     * formName is used for both Javascript and non-javascript validations.
     * For the javascript validations, there is the possibility that we will
     * be rewriting the formName (if it is a ValidatorActionForm instead of just
     * a ValidatorForm) so we need another variable to hold the formName just for
     * javascript usage.
     */
    protected String jsFormName = null;

    /**
     * The line ending string.
     */
    protected static String lineEnd = System.getProperty("line.separator");

    /**
     * The current page number of a multi-part form.
     * Only valid when the formName attribute is set.
     */
    protected int page = 0;

    /**
     * This will be used as is for the JavaScript validation method name if it has a value.  This is
     * the method name of the main JavaScript method that the form calls to perform validations.
     */
    protected String methodName = null;

    /**
     * Include language attribute in the &lt;script&gt; element.  This property is
     * ignored in XHTML mode.
     * @since Struts 1.2
     */
    protected boolean scriptLanguage = true;

    /**
     * The static JavaScript methods will only be printed if this is set to "true".
     */
    protected String staticJavascript = "true";

    /**
     * The dynamic JavaScript objects will only be generated if this is set to "true".
     */
    protected String dynamicJavascript = "true";

    /**
     * The src attribute for html script element (used to include an external script
     * resource). The src attribute is only recognized
     * when the formName attribute is specified.
     */
    protected String src = null;

    /**
     * The JavaScript methods will enclosed with html comments if this is set to "true".
     */
    protected String htmlComment = "true";

    /**
     * Hide JavaScript methods in a CDATA section for XHTML when "true".
     */
    protected String cdata = "true";

    /**
     * Gets the key (form name) that will be used
     * to retrieve a set of validation rules to be
     * performed on the bean passed in for validation.
     */
    public String getFormName() {
        return formName;
    }

    /**
     * Sets the key (form name) that will be used
     * to retrieve a set of validation rules to be
     * performed on the bean passed in for validation.
     * Specifying a form name places a
     * &lt;script&gt; &lt;/script&gt; tag around the javascript.
     */
    public void setFormName(String formName) {
        this.formName = formName;
    }

    /**
     * @return Returns the jsFormName.
     */
    public String getJsFormName() {
        return jsFormName;
    }
    /**
     * @param jsFormName The jsFormName to set.
     */
    public void setJsFormName(String jsFormName) {
        this.jsFormName = jsFormName;
    }
    /**
     * Gets the current page number of a multi-part form.
     * Only field validations with a matching page numer
     * will be generated that match the current page number.
     * Only valid when the formName attribute is set.
     */
    public int getPage() {
        return page;
    }

    /**
     * Sets the current page number of a multi-part form.
     * Only field validations with a matching page numer
     * will be generated that match the current page number.
     * Only valid when the formName attribute is set.
     */
    public void setPage(int page) {
        this.page = page;
    }

    /**
     * Gets the method name that will be used for the Javascript
     * validation method name if it has a value.  This overrides
     * the auto-generated method name based on the key (form name)
     * passed in.
     */
    public String getMethod() {
        return methodName;
    }

    /**
     * Sets the method name that will be used for the Javascript
     * validation method name if it has a value.  This overrides
     * the auto-generated method name based on the key (form name)
     * passed in.
     */
    public void setMethod(String methodName) {
        this.methodName = methodName;
    }

    /**
     * Gets whether or not to generate the static
     * JavaScript.  If this is set to 'true', which
     * is the default, the static JavaScript will be generated.
     */
    public String getStaticJavascript() {
        return staticJavascript;
    }

    /**
     * Sets whether or not to generate the static
     * JavaScript.  If this is set to 'true', which
     * is the default, the static JavaScript will be generated.
     */
    public void setStaticJavascript(String staticJavascript) {
        this.staticJavascript = staticJavascript;
    }

    /**
     * Gets whether or not to generate the dynamic
     * JavaScript.  If this is set to 'true', which
     * is the default, the dynamic JavaScript will be generated.
     */
    public String getDynamicJavascript() {
        return dynamicJavascript;
    }

    /**
     * Sets whether or not to generate the dynamic
     * JavaScript.  If this is set to 'true', which
     * is the default, the dynamic JavaScript will be generated.
     */
    public void setDynamicJavascript(String dynamicJavascript) {
        this.dynamicJavascript = dynamicJavascript;
    }

    /**
      * Gets whether or not to delimit the
      * JavaScript with html comments.  If this is set to 'true', which
      * is the default, the htmlComment will be surround the JavaScript.
      */
    public String getHtmlComment() {
        return htmlComment;
    }

    /**
     * Sets whether or not to delimit the
     * JavaScript with html comments.  If this is set to 'true', which
     * is the default, the htmlComment will be surround the JavaScript.
     */
    public void setHtmlComment(String htmlComment) {
        this.htmlComment = htmlComment;
    }

    /**
     * Gets the src attribute's value when defining
     * the html script element.
     */
    public String getSrc() {
        return src;
    }

    /**
     * Sets the src attribute's value when defining
     * the html script element. The src attribute is only recognized
     * when the formName attribute is specified.
     */
    public void setSrc(String src) {
        this.src = src;
    }

    /**
     * Sets the servlet context attribute key for our resources.
     */
    public String getBundle() {
        return bundle;
    }

    /**
     * Gets the servlet context attribute key for our resources.
     */
    public void setBundle(String bundle) {
        this.bundle = bundle;
    }

    /**
     * Render the JavaScript for to perform validations based on the form name.
     *
     * @exception JspException if a JSP exception has occurred
     */
    public int doStartTag() throws JspException {

        JspWriter writer = pageContext.getOut();
        try {
            writer.print(this.renderJavascript());

        } catch (IOException e) {
            throw new JspException(e.getMessage());
        }

        return EVAL_BODY_TAG;

    }

    /**
     * Returns fully rendered JavaScript.
     * @since Struts 1.2
     */
    protected String renderJavascript() throws JspException {
        StringBuffer results = new StringBuffer();

        ModuleConfig config = TagUtils.getInstance().getModuleConfig(pageContext);
        ValidatorResources resources =
            (ValidatorResources) pageContext.getAttribute(
                ValidatorPlugIn.VALIDATOR_KEY + config.getPrefix(),
                PageContext.APPLICATION_SCOPE);

        if (resources == null) {
            throw new JspException(
                "ValidatorResources not found in application scope under key \"" 
                + ValidatorPlugIn.VALIDATOR_KEY + config.getPrefix() + "\"");
        }        

        Locale locale = TagUtils.getInstance().getUserLocale(this.pageContext, null);

        Form form = resources.getForm(locale, formName);

        if ("true".equalsIgnoreCase(dynamicJavascript) && form == null)
        {
            throw new JspException("No form found under '"
                                   + formName
                                   + "' in locale '"
                                   + locale
                                   + "'");
        }

        if (form != null) {
            if ("true".equalsIgnoreCase(dynamicJavascript)) {
                results.append(
                        this.createDynamicJavascript(config, resources, locale, form));

            } else if ("true".equalsIgnoreCase(staticJavascript)) {
                results.append(this.renderStartElement());
                if ("true".equalsIgnoreCase(htmlComment)) {
                    results.append(HTML_BEGIN_COMMENT);
                }
            }
        }

        if ("true".equalsIgnoreCase(staticJavascript)) {
            results.append(getJavascriptStaticMethods(resources));
        }

        if (form != null
            && ("true".equalsIgnoreCase(dynamicJavascript)
                || "true".equalsIgnoreCase(staticJavascript))) {

            results.append(getJavascriptEnd());
        }

        return results.toString();
    }

    /**
     * Generates the dynamic JavaScript for the form.
     * @param config
     * @param resources
     * @param locale
     * @param form
     */
    private String createDynamicJavascript(
        ModuleConfig config,
        ValidatorResources resources,
        Locale locale,
        Form form) throws JspException {

        StringBuffer results = new StringBuffer();

        MessageResources messages = 
            TagUtils.getInstance().retrieveMessageResources(pageContext, bundle, true);
 
        HttpServletRequest request = (HttpServletRequest)pageContext.getRequest();
        ServletContext application = pageContext.getServletContext();

        List actions = this.createActionList(resources, form);

        final String methods = this.createMethods(actions, this.stopOnError(config));

        String formName = form.getName();
        jsFormName = formName;
                if(jsFormName.charAt(0) == '/') {
                    String mappingName = TagUtils.getInstance().getActionMappingName(jsFormName);
                    ActionMapping mapping = (ActionMapping) config.findActionConfig(mappingName);
                    if (mapping == null) {
                        JspException e = new JspException(messages.getMessage("formTag.mapping", mappingName));
                        pageContext.setAttribute(Globals.EXCEPTION_KEY, e, PageContext.REQUEST_SCOPE);
                        throw e;
                    }
                    jsFormName = mapping.getAttribute();
                }
        
        results.append(this.getJavascriptBegin(methods));

        for (Iterator i = actions.iterator(); i.hasNext();) {
            ValidatorAction va = (ValidatorAction) i.next();
            int jscriptVar = 0;
            String functionName = null;


            if (va.getJsFunctionName() != null
                && va.getJsFunctionName().length() > 0) {
                functionName = va.getJsFunctionName();
            } else {
                functionName = va.getName();
            }

            
            results.append("    function " + jsFormName + "_" + functionName + " () { \n");
            for (Iterator x = form.getFields().iterator(); x.hasNext();) {
                Field field = (Field) x.next();

                // Skip indexed fields for now until there is a good way to handle
                // error messages (and the length of the list (could retrieve from scope?))
                if (field.isIndexed()
                    || field.getPage() != page
                    || !field.isDependency(va.getName())) {

                    continue;
                }

                String message =  Resources.getMessage(application,
                                                       request,
                                                       messages,
                                                       locale,
                                                       va,
                                                       field);

                message = (message != null) ? message : "";

                // prefix variable with 'a' to make it a legal identifier
                results.append(
                    "     this.a"
                        + jscriptVar++
                        + " = new Array(\""
                        + field.getKey()
                        + "\", \""
                        + escapeQuotes(message)
                        + "\", ");

                results.append("new Function (\"varName\", \"");

                Map vars = field.getVars();
                // Loop through the field's variables.
                Iterator varsIterator = vars.keySet().iterator();
                while (varsIterator.hasNext()) {
                    String varName = (String) varsIterator.next();
                    Var var = (Var) vars.get(varName);
                    String varValue = var.getValue();
                    String jsType = var.getJsType();

                    // skip requiredif variables field, fieldIndexed, fieldTest, fieldValue
                    if (varName.startsWith("field")) {
                        continue;
                    }

                    String varValueEscaped = escapeJavascript(varValue);

                    if (Var.JSTYPE_INT.equalsIgnoreCase(jsType)) {
                        results.append(
                            "this."
                                + varName
                                + "="
                                + varValueEscaped
                                + "; ");
                    } else if (Var.JSTYPE_REGEXP.equalsIgnoreCase(jsType)) {
                        results.append(
                            "this."
                                + varName
                                + "=/"
                                + varValueEscaped
                                + "/; ");
                    } else if (Var.JSTYPE_STRING.equalsIgnoreCase(jsType)) {
                        results.append(
                            "this."
                                + varName
                                + "='"
                                + varValueEscaped
                                + "'; ");
                        // So everyone using the latest format doesn't need to change their xml files immediately.
                    } else if ("mask".equalsIgnoreCase(varName)) {
                        results.append(
                            "this."
                                + varName
                                + "=/"
                                + varValueEscaped
                                + "/; ");
                    } else {
                        results.append(
                            "this."
                                + varName
                                + "='"
                                + varValueEscaped
                                + "'; ");
                    }
                }

                results.append(" return this[varName];\"));\n");
            }
            results.append("    } \n\n");
        }

        return results.toString();
    }

    private String escapeQuotes(String in)
    {
        if (in == null || in.indexOf("\"") == -1)
        {
            return in;
        }
        StringBuffer buffer = new StringBuffer();
        StringTokenizer tokenizer = new StringTokenizer(in, "\"", true);

        while (tokenizer.hasMoreTokens())
        {
            String token = tokenizer.nextToken();
            if (token.equals("\""))
            {
                buffer.append("\\");
            }
            buffer.append(token);
        }

        return buffer.toString();
    }

    /**
     * <p>Backslash-escapes the following characters from the input string:
     * &quot;, &apos;, \, \r, \n.</p>
     *
     * <p>This method escapes characters that will result in an invalid
     * Javascript statement within the validator Javascript.</p>
     *
     * @param str The string to escape.
     * @return The string <code>s</code> with each instance of a double quote,
     *         single quote, backslash, carriage-return, or line feed escaped
     *         with a leading backslash.
     *
     * @since Struts 1.2.8
     */
    private String escapeJavascript(String str)
    {
        if (str == null)
        {
            return null;
        }
        int length = str.length();
        if (length == 0)
        {
            return str;
        }

        // guess at how many chars we'll be adding...
        StringBuffer out = new StringBuffer(length + 4);
        // run through the string escaping sensitive chars
        for (int i=0; i < length; i++)
        {
            char c = str.charAt(i);
            if (c == '"'  ||
                c == '\'' ||
                c == '\\' || 
                c == '\n' || 
                c == '\r')
            {
                out.append('\\');
            }
            out.append(c);
        }
        return out.toString();
    }

    /**
     * Determines if validations should stop on an error.
     * @param config The <code>ModuleConfig</code> used to lookup the
     * stopOnError setting.
     * @return <code>true</code> if validations should stop on errors.
     */
    private boolean stopOnError(ModuleConfig config) {
        Object stopOnErrorObj =
            pageContext.getAttribute(
                ValidatorPlugIn.STOP_ON_ERROR_KEY + '.' + config.getPrefix(),
                PageContext.APPLICATION_SCOPE);

        boolean stopOnError = true;

        if (stopOnErrorObj instanceof Boolean) {
            stopOnError = ((Boolean) stopOnErrorObj).booleanValue();
        }

        return stopOnError;
    }

    /**
     * Creates the JavaScript methods list from the given actions.
     * @param actions A List of ValidatorAction objects.
     * @param stopOnError If true, behaves like released version of struts 1.1
     *        and stops after first error. If false, evaluates all validations.
     * @return JavaScript methods.
     */
    private String createMethods(List actions, boolean stopOnError) {
        StringBuffer methods = new StringBuffer();
        final String methodOperator = stopOnError ? " && " : " & ";

        Iterator iter = actions.iterator();
        while (iter.hasNext()) {
            ValidatorAction va = (ValidatorAction) iter.next();

            if (methods.length() > 0) {
                methods.append(methodOperator);
            }
            methods.append(va.getMethod())
                   .append("(form)");
        }

        return methods.toString();
    }

    /**
     * Get List of actions for the given Form.
     * @param resources
     * @param form
     * @return A sorted List of ValidatorAction objects.
     */
    private List createActionList(ValidatorResources resources, Form form) {

        List actionMethods = new ArrayList();

        Iterator iterator = form.getFields().iterator();
        while (iterator.hasNext()) {
            Field field = (Field) iterator.next();

            for (Iterator x = field.getDependencyList().iterator(); x.hasNext();) {
                Object o = x.next();

                if (o != null && !actionMethods.contains(o)) {
                    actionMethods.add(o);
                }
            }
        }

        List actions = new ArrayList();

        // Create list of ValidatorActions based on actionMethods
        iterator = actionMethods.iterator();
        while (iterator.hasNext()) {
            String depends = (String) iterator.next();
            ValidatorAction va = resources.getValidatorAction(depends);

            // throw nicer NPE for easier debugging
            if (va == null) {
                throw new NullPointerException(
                    "Depends string \""
                        + depends
                        + "\" was not found in validator-rules.xml.");
            }

            if (va.getJavascript() != null && va.getJavascript().length() > 0) {
                actions.add(va);
            } else {
                iterator.remove();
            }
        }

        Collections.sort(actions, actionComparator);

        return actions;
    }

    /**
     * Release any acquired resources.
     */
    public void release() {
        super.release();
        bundle = Globals.MESSAGES_KEY;
        formName = null;
        jsFormName = null;
        page = 0;
        methodName = null;
        staticJavascript = "true";
        dynamicJavascript = "true";
        htmlComment = "true";
        cdata = "true";
        src = null;
    }

    /**
     * Returns the opening script element and some initial javascript.
     */
    protected String getJavascriptBegin(String methods) {
        StringBuffer sb = new StringBuffer();
        String name = jsFormName.replace('/', '_'); // remove any '/' characters
        name =
            jsFormName.substring(0, 1).toUpperCase()
                + jsFormName.substring(1, jsFormName.length());

        sb.append(this.renderStartElement());

        if (this.isXhtml() && "true".equalsIgnoreCase(this.cdata)) {
            sb.append("//<![CDATA[\r\n");
        }

        if (!this.isXhtml() && "true".equals(htmlComment)) {
            sb.append(HTML_BEGIN_COMMENT);
        }
        sb.append("\n    var bCancel = false; \n\n");

        if ((methodName == null) || (methodName.length() == 0)) {
            sb.append("    function validate" + name + "(form) { \n");
        } else {
            sb.append("    function " + methodName + "(form) { \n");
        }

        sb.append("        if (bCancel) { \n");
        sb.append("            return true; \n");
        sb.append("        } else { \n");

        // Always return true if there aren't any Javascript validation methods
        if ((methods == null) || (methods.length() == 0)) {
            sb.append("            return true; \n");
        } else {
            sb.append("            var formValidationResult; \n");
            sb.append("            formValidationResult = " + methods + "; \n");
            if (methods.indexOf("&&") >= 0) {
                sb.append("            return (formValidationResult); \n");
            } else {
                //Making Sure that Bitwise operator works:
                sb.append("            return (formValidationResult == 1); \n");
            }
        }
        sb.append("        } \n");
        sb.append("    } \n\n");

        return sb.toString();
    }

    protected String getJavascriptStaticMethods(ValidatorResources resources) {
        StringBuffer sb = new StringBuffer();

        sb.append("\n\n");

        Iterator actions = resources.getValidatorActions().values().iterator();
        while (actions.hasNext()) {
            ValidatorAction va = (ValidatorAction) actions.next();
            if (va != null) {
                String javascript = va.getJavascript();
                if (javascript != null && javascript.length() > 0) {
                    sb.append(javascript + "\n");
                }
            }
        }

        return sb.toString();
    }

    /**
     * Returns the closing script element.
     */
    protected String getJavascriptEnd() {
        StringBuffer sb = new StringBuffer();

        sb.append("\n");
        if (!this.isXhtml() && "true".equals(htmlComment)){
            sb.append(HTML_END_COMMENT);
        }

        if (this.isXhtml() && "true".equalsIgnoreCase(this.cdata)) {
            sb.append("//]]>\r\n");
        }

        sb.append("</script>\n\n");

        return sb.toString();
    }

    /**
     * Constructs the beginning &lt;script&gt; element depending on XHTML
     * status.
     * @since Struts 1.2
     */
    protected String renderStartElement() {
        StringBuffer start = new StringBuffer("<script type=\"text/javascript\"");

        // there is no language attribute in XHTML
        if (!this.isXhtml() && this.scriptLanguage) {
            start.append(" language=\"Javascript1.1\"");
        }

        if (this.src != null) {
            start.append(" src=\"" + src + "\"");
        }

        start.append("> \n");
        return start.toString();
    }

    /**
     * Returns true if this is an xhtml page.
     */
    private boolean isXhtml() {
        return TagUtils.getInstance().isXhtml(this.pageContext);
    }

    /**
     * Returns the cdata setting "true" or "false".
     * @return String - "true" if JavaScript will be hidden in a CDATA section
     */
    public String getCdata() {
        return cdata;
    }

    /**
     * Sets the cdata status.
     * @param cdata The cdata to set
     */
    public void setCdata(String cdata) {
        this.cdata = cdata;
    }

    /**
     * Gets whether or not the &lt;script&gt; element will include the
     * language attribute.
     * @return true if language attribute will be included.
     * @since Struts 1.2
     */
    public boolean getScriptLanguage() {
        return this.scriptLanguage;
    }

    /**
     * Sets whether or not the &lt;script&gt; element will include the
     * language attribute.
     * @since Struts 1.2
     */
    public void setScriptLanguage(boolean scriptLanguage) {
        this.scriptLanguage = scriptLanguage;
    }

}
