package com.temp.shared.externalization;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import com.temp.shared.utils.Assert;
import com.temp.shared.utils.StringUtils;

/**
 * Externalization Data to be used with an Externally Sourced String keyed
 * template system that supports substitutions within any specific template by
 * "named" values.
 */
public class E13nData {

    /**
     * Substitution Value w/ a flag indicating if it is User Data, or another
     * Template Id Code to be used as a Sub-Template.
     */
    public static class SubstitutionValue {
        private final boolean userData;
        private final String value;

        public SubstitutionValue(boolean userData, String value) {
            this.userData = userData;
            this.value = value;
        }

        /**
         * Flag indicating if the "value" is User Data, or another Template Id
         * Code to be used as a Sub-Template.
         */
        public boolean isUserData() {
            return userData;
        }

        /**
         * User Data, or another Template Id Code to be used as a Sub-Template.
         */
        public String getValue() {
            return value;
        }

        @Override
        public String toString() {
            return userData ? value : "{" + value + "}";
        }
    }

    private final String templateIdCode;
    private Map<String, SubstitutionValue> templateSubstitutionNamedValues;

    /**
     * Convert the templateIdCode (parameter) into an acceptable string form for
     * the templateIdCode.
     *
     * @param templateIdCode
     *            Template Identifying Code
     */
    public E13nData(Object templateIdCode) {
        this.templateIdCode = Assert.noEmptyToString("templateIdCode", templateIdCode);
    }

    private synchronized E13nData addPair(boolean userData, String name, String value) {
        name = Assert.noEmpty("name", name);
        if (templateSubstitutionNamedValues == null) {
            templateSubstitutionNamedValues = new HashMap<String, SubstitutionValue>();
        }
        templateSubstitutionNamedValues.put(name, new SubstitutionValue(userData, value));
        return this;
    }

    /**
     * Add a User Substitution Named Value.
     *
     * @param name
     *            Not allowed to be empty
     * @param userData
     *            null converted to ""
     */
    public E13nData addSubstitutionNamedUserData(String name, String userData) {
        return addPair(true, name, StringUtils.deNull(userData));
    }

    /**
     * Add a User Substitution Named Value.
     *
     * @param name
     *            Not allowed to be empty
     * @param subTemplateIdCode
     *            Not allowed to be empty
     */
    public E13nData addSubstitutionNamedSubTemplateIdCode(String name, String subTemplateIdCode) {
        return addPair(false, name, Assert.noEmpty("subTemplateIdCode", subTemplateIdCode));
    }

    /**
     * @return Not Empty TemplateIdCode
     */
    public String getTemplateIdCode() {
        return templateIdCode;
    }

    /**
     * @return Not null map of Template Substitution Named Values
     */
    public synchronized Map<String, SubstitutionValue> getTemplateSubstitutionNamedValues() {
        if (templateSubstitutionNamedValues == null) {
            return Collections.emptyMap();
        }
        return new HashMap<String, SubstitutionValue>(templateSubstitutionNamedValues); // defensive copy for Thread Safety
    }

    @Override
    public String toString() {
        return getTemplateIdCode() + getTemplateSubstitutionNamedValues();
    }
}