package ddth.dasp.framework.osgi.freemarker;

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;

import ddth.dasp.framework.osgi.BundleResourceLoader;
import ddth.dasp.framework.resource.IResourceLoader;
import freemarker.cache.TemplateLoader;

/**
 * This FreeMarker's {@link TemplateLoader} uses {@link BundleResourceLoader} to
 * load resources.
 * 
 * @author NBThanh <btnguyen2k@gmail.com>
 */
public class BundleTemplateLoader implements TemplateLoader {

    private IResourceLoader resourceLoader;
    private String prefix, suffix;

    protected IResourceLoader getResourceLoader() {
        return resourceLoader;
    }

    public void setResourceLoader(IResourceLoader resourceLoader) {
        this.resourceLoader = resourceLoader;
    }

    protected String getPrefix() {
        return prefix;
    }

    public void setPrefix(String prefix) {
        this.prefix = prefix;
        if (prefix.endsWith("/")) {
            prefix.replaceAll("\\/+$", "/");
        } else {
            prefix += "/";
        }
    }

    protected String getSuffix() {
        return suffix;
    }

    public void setSuffix(String suffix) {
        this.suffix = suffix;
    }

    /**
     * Builds template resource's full path.
     * 
     * @param name
     * @return
     */
    protected String buildPath(String name) {
        String path = name;
        if (name.startsWith("/")) {
            name = name.replaceAll("^\\/+", "");
        }
        if (prefix != null) {
            path = prefix + name;
        }
        if (suffix != null) {
            path += suffix;
        }
        return path;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void closeTemplateSource(Object templateSource) throws IOException {
        // empty since there is no thing to "close"
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public Object findTemplateSource(String name) throws IOException {
        String realPath = buildPath(name);
        return resourceLoader.resourceExists(realPath) ? name : null;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public long getLastModified(Object templateSource) {
        String realPath = buildPath(templateSource.toString());
        // return resourceLoader.getLastModified(buildPath(realPath));
        return resourceLoader.getLastModified(realPath);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public Reader getReader(Object templateSource, String encoding) throws IOException {
        String realPath = buildPath(templateSource.toString());
        String resourceContent = resourceLoader.loadResourceAsString(realPath, encoding);
        return new StringReader(resourceContent);
    }
}