/**
 * Copyright 2010-2014 The Kuali Foundation
 *
 * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
 *
 * 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.kuali.common.util.spring.env;

import java.io.File;

import org.kuali.common.util.Assert;
import org.kuali.common.util.Mode;
import org.kuali.common.util.ModeUtils;
import org.springframework.core.env.Environment;

/**
 * <p>
 * By default, an exception is thrown if a value cannot be located (unless a default value has been supplied).
 * </p>
 * 
 * <p>
 * By default, an exception is thrown if any placeholders cannot be resolved in any string values.
 * </p>
 * 
 * <p>
 * By default, environment variables are automatically checked if a normal property value cannot be found.
 * 
 * For example, given the key <code>db.vendor</code> the service will also automatically check <code>env.DB_VENDOR</code>
 * </p>
 * 
 * @deprecated Use BasicEnvironmentService instead
 */
@Deprecated
public class DefaultEnvironmentService implements EnvironmentService {

        public static final boolean DEFAULT_CHECK_ENVIRONMENT_VARIABLES = true;
        public static final boolean DEFAULT_RESOLVE_STRINGS = true;
        public static final Mode DEFAULT_MISSING_PROPERTY_MODE = Mode.ERROR;
        public static final String ENV_PREFIX = "env";

        private final boolean checkEnvironmentVariables;
        private final boolean resolveStrings;
        private final Environment env;
        private final Mode missingPropertyMode;

        public DefaultEnvironmentService(Environment env) {
                this(env, DEFAULT_CHECK_ENVIRONMENT_VARIABLES, DEFAULT_RESOLVE_STRINGS, DEFAULT_MISSING_PROPERTY_MODE);
        }

        public DefaultEnvironmentService(Environment env, boolean checkEnvironmentVariables) {
                this(env, checkEnvironmentVariables, DEFAULT_RESOLVE_STRINGS, DEFAULT_MISSING_PROPERTY_MODE);
        }

        public DefaultEnvironmentService(Environment env, boolean checkEnvironmentVariables, boolean resolveStrings, Mode missingPropertyMode) {
                Assert.noNulls(env, missingPropertyMode);
                this.env = env;
                this.missingPropertyMode = missingPropertyMode;
                this.checkEnvironmentVariables = checkEnvironmentVariables;
                this.resolveStrings = resolveStrings;
        }

        @Override
        public boolean containsProperty(String key) {
                Assert.noBlanks(key);
                return env.containsProperty(key);
        }

        @Override
        public <T> T getProperty(EnvContext<T> context) {

                // If context is null, we have issues
                Assert.noNulls(context);

                // Extract a value from Spring's Environment abstraction
                T springValue = getSpringValue(context.getKey(), context.getType());

                // If that value is null, use whatever default value they gave us (this might also be null)
                T returnValue = (springValue == null) ? context.getDefaultValue() : springValue;

                // If we could not locate a value, we may need to error out
                if (returnValue == null) {
                        ModeUtils.validate(missingPropertyMode, getMissingPropertyMessage(context.getKey()));
                }

                // Return the value we've located
                return returnValue;
        }

        protected String getMissingPropertyMessage(String key) {
                if (checkEnvironmentVariables) {
                        String envKey = EnvUtils.getEnvironmentVariableKey(key);
                        return "No value for [" + key + "] or [" + envKey + "]";
                } else {
                        return "No value for [" + key + "]";
                }
        }

        protected <T> T getSpringValue(String key, Class<T> type) {
                T value = env.getProperty(key, type);
                if (value == null && checkEnvironmentVariables) {
                        String envKey = EnvUtils.getEnvironmentVariableKey(key);
                        return env.getProperty(envKey, type);
                } else {
                        return value;
                }
        }

        protected <T> Class<T> getSpringValueAsClass(String key, Class<T> type) {
                Class<T> value = env.getPropertyAsClass(key, type);
                if (value == null && checkEnvironmentVariables) {
                        String envKey = EnvUtils.getEnvironmentVariableKey(key);
                        return env.getPropertyAsClass(envKey, type);
                } else {
                        return value;
                }
        }

        @Override
        public <T> Class<T> getClass(String key, Class<T> type) {
                return getClass(key, type, null);
        }

        @Override
        public <T> Class<T> getClass(String key, Class<T> type, Class<T> defaultValue) {
                Class<T> springValue = getSpringValueAsClass(key, type);
                Class<T> returnValue = (springValue == null) ? defaultValue : springValue;

                // If we could not locate a value, we may need to error out
                if (returnValue == null) {
                        ModeUtils.validate(missingPropertyMode, getMissingPropertyMessage(key));
                }

                // Return what we've got
                return returnValue;
        }

        @Override
        public String getString(String key) {
                return getString(key, null);
        }

        @Override
        public String getString(String key, String defaultValue) {
                String string = getProperty(EnvContext.newString(key, defaultValue));
                if (resolveStrings) {
                        return env.resolveRequiredPlaceholders(string);
                } else {
                        return string;
                }
        }

        @Override
        public Boolean getBoolean(String key) {
                return getBoolean(key, null);
        }

        @Override
        public Boolean getBoolean(String key, Boolean defaultValue) {
                return getProperty(EnvContext.newBoolean(key, defaultValue));
        }

        @Override
        public File getFile(String key) {
                return getFile(key, null);
        }

        @Override
        public File getFile(String key, File defaultValue) {
                return getProperty(EnvContext.newFile(key, defaultValue));
        }

        @Override
        public Integer getInteger(String key, Integer defaultValue) {
                return getProperty(EnvContext.newInteger(key, defaultValue));
        }

        @Override
        public Integer getInteger(String key) {
                return getInteger(key, null);
        }

        public boolean isCheckEnvironmentVariables() {
                return checkEnvironmentVariables;
        }

        public boolean isResolveStrings() {
                return resolveStrings;
        }

        public Environment getEnv() {
                return env;
        }

        public Mode getMissingPropertyMode() {
                return missingPropertyMode;
        }

        @Override
        public <T> T getProperty(String key, Class<T> type, T provided) {
                return getProperty(EnvContext.newCtx(key, type, provided));
        }

        @Override
        public <T> T getProperty(String key, Class<T> type) {
                return getProperty(EnvContext.newCtx(key, type, null));
        }

}