/**

* Copyright 2012 Twitter, Inc

*

* 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 ua_parser;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

/**

* Device parser using ua-parser regexes. Extracts device information from user agent strings.

*

* @author Steve Jiang (@sjiang) <gh at iamsteve com>

*/

public class DeviceParser {

List<DevicePattern> patterns;

public DeviceParser(List<DevicePattern> patterns) {

this.patterns = patterns;

}

public Device parse(String agentString) {

if (agentString == null) {

return null;

}

String device = null;

for (DevicePattern p : patterns) {

if ((device = p.match(agentString)) != null) {

break;

}

}

if (device == null) device = "Other";

return new Device(device);

}

public static DeviceParser fromList(List<Map<String,String>> configList) {

List<DevicePattern> configPatterns = new ArrayList<DevicePattern>();

for (Map<String,String> configMap : configList) {

configPatterns.add(DeviceParser.patternFromMap(configMap));

}

return new DeviceParser(configPatterns);

}

protected static DevicePattern patternFromMap(Map<String, String> configMap) {

String regex = configMap.get("regex");

if (regex == null) {

throw new IllegalArgumentException("Device is missing regex");

}

Pattern pattern = "i".equals(configMap.get("regex_flag")) // no ohter flags used (by now)

? Pattern.compile(regex, Pattern.CASE_INSENSITIVE) : Pattern.compile(regex);

return new DevicePattern(pattern, configMap.get("device_replacement"));

}

protected static class DevicePattern {

private static final Pattern SUBSTITUTIONS_PATTERN = Pattern.compile("\\$\\d");

private final Pattern pattern;

private final String deviceReplacement;

public DevicePattern(Pattern pattern, String deviceReplacement) {

this.pattern = pattern;

this.deviceReplacement = deviceReplacement;

}

public String match(String agentString) {

Matcher matcher = pattern.matcher(agentString);

if (!matcher.find()) {

return null;

}

String device = null;

if (deviceReplacement != null) {

if (deviceReplacement.contains("$")) {

device = deviceReplacement;

for (String substitution : getSubstitutions(deviceReplacement)) {

int i = Integer.valueOf(substitution.substring(1));

String replacement = matcher.groupCount() >= i && matcher.group(i) != null

? Matcher.quoteReplacement(matcher.group(i)) : "";

device = device.replaceFirst("\\" + substitution, replacement);

}

device = device.trim();

} else {

device = deviceReplacement;

}

} else if (matcher.groupCount() >= 1) {

device = matcher.group(1);

}

return device;

}

private List<String> getSubstitutions(String deviceReplacement) {

Matcher matcher = SUBSTITUTIONS_PATTERN.matcher(deviceReplacement);

List<String> substitutions = new ArrayList<String>();

while (matcher.find()) {

substitutions.add(matcher.group());

}

return substitutions;

}

}

}