package uk.ac.uos.i2p.assignment;

import java.util.HashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class TemplateManager implements TemplateProcessor {

    private Map<String, String> map;

    public TemplateManager() {
        this.map = new HashMap<String, String>();
    }

    @Override
    public void loadTemplate(String name, String template) {
        if (name != "" && template != "")
            this.map.put(name, template);
        else
            System.err.println("Empty data, impossible to add in the Map");

    }

    @Override
    public void loadTemplates(Map<String, String> templates) {
        this.map.putAll(templates);
    }

    @Override
    public String expandTemplate(String templateName, Map<String, Object> context) {
        if (this.map.containsKey(templateName)) {
            int leftOffset = 2, rightOffset = 1;
            String result = map.get(templateName), extractedValue = "";
            StringBuffer sb = new StringBuffer();
            Pattern pattern = Pattern.compile("\\$\\{\\(?\\w+\\)?\\}");
            Matcher matcher = pattern.matcher(result);


            while (matcher.find()) {

                if (matcher.group().charAt(2) == '(') {
                    leftOffset = 3;
                    rightOffset = 2;
                } else {
                    leftOffset = 2;
                    rightOffset = 1;
                }
                extractedValue = matcher.group().substring(leftOffset, matcher.group().length() - rightOffset);

                if (context.containsKey(extractedValue)) {
                    matcher.appendReplacement(sb, context.get(extractedValue).toString());
                }
                //First expression//
                if (context.containsKey(extractedValue) && context.get(extractedValue) != null) {
                    matcher.appendReplacement(sb, context.get(extractedValue).toString());
                }

            }
            return sb.toString();
        } else {
            System.out.println("Template \"" + templateName + "\" not found!");
            return null;
        }



    }
}