package org.kuali.common.devops.jenkins.scan.function;
   
   import static com.google.common.base.Preconditions.checkArgument;
   import static org.kuali.common.util.base.Exceptions.illegalState;
   import static org.kuali.common.util.base.Precondition.checkNotNull;
   
   import java.io.File;
   import java.text.ParseException;
   import java.text.SimpleDateFormat;
  import java.util.Date;
  import java.util.TimeZone;
  
  import org.kuali.common.core.build.ValidatingBuilder;
  import org.kuali.common.core.validate.annotation.IdiotProofImmutable;
  import org.kuali.common.util.file.CanonicalFile;
  
  import com.google.common.base.Function;
  
  @IdiotProofImmutable
  public final class JobExecutionStartTimeFunction implements Function<File, Long> {
  
  	private final String datePattern;
  	private final String timeZoneId;
  
  	@Override
  	public Long apply(File jenkinsBuildDirectory) {
  
  		// Null not allowed
  		checkNotNull(jenkinsBuildDirectory, "jenkinsBuildDirectory");
  
  		// Directories only
  		checkArgument(jenkinsBuildDirectory.isDirectory(), "[%s] is not an existing directory", jenkinsBuildDirectory);
  
  		// New instance every single time since SimpleDateFormat is not threadsafe
  		SimpleDateFormat sdf = new SimpleDateFormat(datePattern);
  		sdf.setTimeZone(TimeZone.getTimeZone(timeZoneId));
  
  		// Convert the file to canonical form
  		File canonical = new CanonicalFile(jenkinsBuildDirectory);
  
  		// Extract the path
  		String path = canonical.getPath();
  
  		// The right most part of the path is a date indicating when the build started
  		String dateFragment = path.substring(path.lastIndexOf(File.separator) + 1);
  
  		// Parse a date object out of the string and return milliseconds since the epoch
  		try {
  			Date date = sdf.parse(dateFragment);
  			return date.getTime();
  		} catch (ParseException e) {
  			throw illegalState(e);
  		}
  	}
  
  	private JobExecutionStartTimeFunction(Builder builder) {
  		this.datePattern = builder.datePattern;
  		this.timeZoneId = builder.timeZoneId;
  	}
  
  	public static JobExecutionStartTimeFunction build() {
  		return builder().build();
  	}
  
  	public static Builder builder() {
  		return new Builder();
  	}
  
  	public static class Builder extends ValidatingBuilder<JobExecutionStartTimeFunction> {
  
  		private String datePattern = "yyyy-MM-dd_HH-mm-ss";
  		private String timeZoneId = "US/Eastern";
  
  		public Builder withDatePattern(String pattern) {
  			this.datePattern = pattern;
  			return this;
  		}
  
  		public Builder withTimeZoneId(String timeZoneId) {
  			this.timeZoneId = timeZoneId;
  			return this;
  		}
  
  		@Override
  		public JobExecutionStartTimeFunction build() {
  			return validate(new JobExecutionStartTimeFunction(this));
  		}
  	}
  
  	public String getDatePattern() {
  		return datePattern;
  	}
  
  	public String getTimeZoneId() {
  		return timeZoneId;
  	}
  }