/**
 * 時間以及時間格式處理
 * */

package com.lianjiping.democ;

import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.Locale;

public class DateFormatUtils {
    //系統默認日期格式
    public static final String DATE_FORMAT = "yyyy-MM-dd";

    //系統默認日期時間格式
    public static final String DATE_TIME_FORMAT = "yyyy-MM-dd HH:mm:ss";

    //8位日期格式
    public static final String DATE_FORMAT_8 = "yyyyMMdd";

    //14位日期時間格式
    public static final String DATE_TIME_FORMAT_14 = "yyyyMMddHHmmss";

    public final static String YEAR = "year";
    public final static String MONTH = "month";
    public final static String DAY = "day";
    public final static String WEEK = "week";
    public final static String HOUR = "hour";
    public final static String MINUTE = "minute";
    public final static String SECOND = "second";

    //判斷參數是否等于空
    private static boolean checkPara(Object para) {
        if (null == para || "".equals(para)) {
            return true;
        } else {
            return false;
        }
    }

    //獲得系統的當前時間(毫秒)
    public static long getCurrentTimeMillis() {
        return System.currentTimeMillis();
    }

    //獲得系統的當前時間
    public static Date getCurrentDate() {
//        return new Date(System.currentTimeMillis());
        return new Date(getCurrentTimeMillis());
    }

    //獲得系統的當前日期(默認格式)
    public static String getCurrentFormatDate() {
        Date currentDate = getCurrentDate();
        SimpleDateFormat dateFormator = new SimpleDateFormat(
                DateFormatUtils.DATE_FORMAT);
        return dateFormator.format(currentDate);
    }

    //獲得系統的當前日期時間(默認格式)
    public static String getCurrentFormatDateTime() {
        Date currentDate = getCurrentDate();
        SimpleDateFormat dateFormator = new SimpleDateFormat(
                DateFormatUtils.DATE_TIME_FORMAT);
        return dateFormator.format(currentDate);
    }

    //獲得系統的當前日期時間(指定格式返回)
    public static String getCurrentCustomFormatDateTime(String pattern) {
        if (checkPara(pattern)) {
            return "";
        }
        Date currentDate = getCurrentDate();
        SimpleDateFormat dateFormator = new SimpleDateFormat(pattern);
        return dateFormator.format(currentDate);
    }

    //輸入日期(指定格式返回)
    public static String formatDate(Date date, String pattern) {
        if (checkPara(pattern) || checkPara(date)) {
            return "";
        }
        SimpleDateFormat dateFormator = new SimpleDateFormat(pattern);
        return dateFormator.format(date);
    }

    //輸入日期(指定格式返回)
    public static String formatDate(Date date, String pattern, Locale locale) {
        if (checkPara(pattern) || checkPara(date)) {
            return "";
        }
        if (checkPara(locale)) {
            locale = Locale.getDefault();
        }
        SimpleDateFormat dateFormator = new SimpleDateFormat(pattern, locale);
        String customFormatDate = dateFormator.format(date);
        return customFormatDate;
    }

    //將時間字符串按照默認格式(DATE_FORMAT = "yyyy-MM-dd")轉換為Date
    public static Date parseStrToDate(String dateStr) {
        if (checkPara(dateStr)) {
            return null;
        }
        SimpleDateFormat dateFormator = new SimpleDateFormat(
                DateFormatUtils.DATE_FORMAT);
        Date resDate = dateFormator.parse(dateStr, new ParsePosition(0));
        return resDate;
    }

    //將時間字符串按照默認格式(DATE_TIME_FORMAT = "yyyy-MM-dd HH:mm:ss")轉換為Date
    public static Date parseStrToDateTime(String dateStr) {
        if (checkPara(dateStr)) {
            return null;
        }
        SimpleDateFormat dateFormator = new SimpleDateFormat(
                DateFormatUtils.DATE_TIME_FORMAT);
        Date resDate = dateFormator.parse(dateStr, new ParsePosition(0));
        return resDate;
    }

    //將時間字符串按照默認格式(DATE_FORMAT = "yyyy-MM-dd")轉換為Calender
    public static Calendar parseStrToCalendar(String dateStr) {
        if (checkPara(dateStr)) {
            return null;
        }
        SimpleDateFormat dateFormator = new SimpleDateFormat(
                DateFormatUtils.DATE_TIME_FORMAT);
        Date resDate = dateFormator.parse(dateStr, new ParsePosition(0));
        Locale locale = Locale.getDefault();
        Calendar cal = new GregorianCalendar(locale);
        cal.setTime(resDate);
        return cal;
    }

    //將日期字符串轉換成日期時間字符串
    public static String parseDateStrToDateTimeStr(String dateStr) {
        if (checkPara(dateStr)) {
            return "";
        }
        SimpleDateFormat dateFormator = new SimpleDateFormat(
                DateFormatUtils.DATE_FORMAT);
        Date resDate = dateFormator.parse(dateStr, new ParsePosition(0));
        return formatDate(resDate, DateFormatUtils.DATE_TIME_FORMAT);
    }


    //將時間或者時間日期字符串按照指定格式轉換為Date
    public static Date parseStrToCustomPatternDate(String dateStr,
            String pattern) {
        if (checkPara(pattern) || checkPara(dateStr)) {
            return null;
        }
        SimpleDateFormat dateFormator = new SimpleDateFormat(
                pattern);
        Date resDate = dateFormator.parse(dateStr, new ParsePosition(0));

        return resDate;
    }

    //將時間字符串從一種格式轉換成另一種格式
    public static String convertDatePattern(String dateStr,
                                            String patternFrom,
                                            String patternTo) {
        if (checkPara(patternFrom) || checkPara(patternTo) || checkPara(dateStr)) {
            return "";
        }
        SimpleDateFormat dateFormator = new SimpleDateFormat(
                patternFrom);
        Date resDate = dateFormator.parse(dateStr, new ParsePosition(0));
        return formatDate(resDate, patternTo);
    }

    /** */
    /**
     * 日期天數增加
     *  @param  date
     *  @param  days
     *  @return
     */
    public static Date addDays(Date date, int days) {
        if (checkPara(date)) {
            return null;
        }
        if (0 == days) {
            return date;
        }
        Locale loc = Locale.getDefault();
        Calendar cal = new GregorianCalendar(loc);
        cal.setTime(date);
        cal.add(Calendar.DAY_OF_MONTH, days);

        return cal.getTime();
    }

    /** */
    /**
     * 日期天數減少
     *  @param  date
     *  @param  days
     *  @return
     */
    public static Date minusDays(Date date, int days) {
        return addDays(date, (0 - days));
    }

    /** */
    /**
     * 按時間格式相加
     *  @param  dateStr    原來的時間
     *  @param  pattern    時間格式
     *  @param  type
     *                     "year"年、"month"月、"day"日、"week"周、
     *                     "hour"時、"minute"分、"second"秒
     *                     通過常量來設置,e.g.DateFormatUtils.YEAR
     *  @param  count        相加數量
     *  @return
     */
    public static String addDate(String dateStr, String pattern,
                                 String type, int count) {
        if (checkPara(dateStr) || checkPara(pattern) || checkPara(type)) {
            return "";
        }
        if (0 == count) {
            return dateStr;
        }
        Date date = parseStrToCustomPatternDate(dateStr, pattern);
        Locale loc = Locale.getDefault();
        Calendar cal = new GregorianCalendar(loc);
        cal.setTime(date);

        if (DateFormatUtils.YEAR.equals(type)) {
            cal.add(Calendar.YEAR, count);
        } else if (DateFormatUtils.MONTH.equals(type)) {
            cal.add(Calendar.MONTH, count);
        } else if (DateFormatUtils.DAY.equals(type)) {
            cal.add(Calendar.DAY_OF_MONTH, count);
        } else if (DateFormatUtils.WEEK.equals(type)) {
            cal.add(Calendar.WEEK_OF_MONTH, count);
        } else if (DateFormatUtils.HOUR.equals(type)) {
            cal.add(Calendar.HOUR, count);
        } else if (DateFormatUtils.MINUTE.equals(type)) {
            cal.add(Calendar.MINUTE, count);
        } else if (DateFormatUtils.SECOND.equals(type)) {
            cal.add(Calendar.SECOND, count);
        } else {
            return "";
        }

        return formatDate(cal.getTime(), pattern);
    }

    /** */
    /**
     * 那時間格式相減
     *  @param  dateStr
     *  @param  pattern
     *  @param  type
     *  @param  count
     *  @return
     */
    public static String minusDate(String dateStr, String pattern,
                                   String type, int count) {
        return addDate(dateStr, pattern, type, (0 - count));
    }

    /** */
    /**
     * 日期大小比較
     *  @param  dateStr1
     *  @param  dateStr2
     *  @param  pattern
     *  @return
     */
    public static int compareDate(String dateStr1, String dateStr2,
                                  String pattern) {
        if (checkPara(dateStr1) || checkPara(dateStr2) || checkPara(pattern)) {
            return 888;
        }
        Date date1 = DateFormatUtils.parseStrToCustomPatternDate(dateStr1,
                pattern);
        Date date2 = DateFormatUtils.parseStrToCustomPatternDate(dateStr2,
                pattern);

        return date1.compareTo(date2);
    }

    /** */
    /**
     * 獲得這個月的第一天
     *  @param  dateStr
     *  @return
     */
    public static String getFirstDayInMonth(String dateStr) {
        if (checkPara(dateStr)) {
            return "";
        }
        Calendar cal = DateFormatUtils.parseStrToCalendar(dateStr);
        int firstDay = cal.getActualMinimum(Calendar.DAY_OF_MONTH);
        cal.set(Calendar.DAY_OF_MONTH, firstDay);

        return DateFormatUtils.formatDate(cal.getTime(),
                                          DateFormatUtils.DATE_FORMAT);
    }

    /** */
    /**
     * 獲得這個月的最后一天
     *  @param  dateStr
     *  @return
     */
    public static String getLastDayInMonth(String dateStr) {
        if (checkPara(dateStr)) {
            return "";
        }
        Calendar cal = DateFormatUtils.parseStrToCalendar(dateStr);
        int lastDay = cal.getActualMaximum(Calendar.DAY_OF_MONTH);
        cal.set(Calendar.DAY_OF_MONTH, lastDay);

        return DateFormatUtils.formatDate(cal.getTime(),
                                          DateFormatUtils.DATE_FORMAT);
    }

    /** */
    /**
     * 獲得這周的第一天
     *  @param  dateStr
     *  @return
     */
    public static String getFirstDayInWeek(String dateStr) {
        if (checkPara(dateStr)) {
            return "";
        }
        Calendar cal = DateFormatUtils.parseStrToCalendar(dateStr);
        int firstDay = cal.getActualMinimum(Calendar.DAY_OF_WEEK);
        cal.set(Calendar.DAY_OF_WEEK, firstDay);

        return DateFormatUtils.formatDate(cal.getTime(),
                                          DateFormatUtils.DATE_FORMAT);
    }

    //本周最后一天
    public static String getLastDayInWeek(String dateStr) {
        if (checkPara(dateStr)) {
            return "";
        }
        Calendar cal = DateFormatUtils.parseStrToCalendar(dateStr);
        int lastDay = cal.getActualMaximum(Calendar.DAY_OF_WEEK);
        cal.set(Calendar.DAY_OF_WEEK, lastDay);
        return DateFormatUtils.formatDate(cal.getTime(),
                                          DateFormatUtils.DATE_FORMAT);
    }
}