apewer-dotnet/Apewer/ClockUtility.cs

using Apewer.Internals;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.Text;

using static System.DateTime;

namespace Apewer
{

    /// <summary>时钟。</summary>
    public static class ClockUtility
    {

        #region DateTime

        /// <summary>尝试转换内容为 DateTime 实例。</summary>
        public static Class<DateTime> DateTime(object value)
        {
            if (value is DateTime dt) return dt;
            if (value.IsNull()) return null;

            DateTime result;
            try
            {
                var text = value.ToString();
                var parsed = System.DateTime.TryParse(text, out result);
                return parsed ? new Class<DateTime>(result) : null;
            }
            catch
            {
                return null;
            }
        }

        #endregion

        #region Fixed

        private static DateTime _zero = new DateTime(0L, DateTimeKind.Unspecified);
        private static DateTime _origin = NewOrigin(DateTimeKind.Unspecified);
        private static DateTime _utc_origin = NewOrigin(DateTimeKind.Utc);

        /// <summary>创建新的零值 DateTime 对象。</summary>
        public static DateTime Zero { get => _zero; }

        /// <summary>获取一个 DateTime 对象，该对象设置为 1970-01-01 00:00:00.000，表示为本地时间。</summary>
        public static DateTime Origin { get => _origin; }

        /// <summary>获取一个 DateTime 对象，该对象设置为 1970-01-01 00:00:00.000，表示为协调通用时间 (UTC)。</summary>
        public static DateTime UtcOrigin { get => _utc_origin; }

        /// <summary>获取一个 DateTime 对象，该对象设置为此计算机上的当前日期和时间，表示为本地时间。</summary>
        public static DateTime Now { get => System.DateTime.Now; }

        /// <summary>获取一个 DateTime 对象，该对象设置为此计算机上的当前日期和时间，表示为协调通用时间 (UTC)。</summary>
        public static DateTime UtcNow { get => System.DateTime.UtcNow; }

        /// <summary>创建一个 DateTime 对象，该对象设置为 1970-01-01 00:00:00.000。</summary>
        public static DateTime NewOrigin(DateTimeKind kind) => new DateTime(1970, 1, 1, 0, 0, 0, 0, kind);

        #endregion

        #region Clone

        /// <summary>克隆 DateTime 对象，并使用新的 Kind。</summary>
        /// <param name="dateTime">要克隆的 DateTime 对象。</param>
        /// <param name="kind">时间类型。</param>
        /// <returns>克隆后带有新 Kind 的 DateTime 对象。</returns>
        public static DateTime Clone(this DateTime dateTime, DateTimeKind kind)
        {
            return new DateTime(dateTime.Ticks, kind);
        }

        #endregion

        #region Common

        /// <summary>判断指定年份是闰年。</summary>
        public static bool IsLeapYear(this int year)
        {
            if (year % 400 == 0) return true;
            if (year % 100 == 0) return false;
            if (year % 4 == 0) return true;
            return false;
        }

        /// <summary>判断指定年份是闰年。</summary>
        public static bool IsLeapYear(DateTime datetime) => IsLeapYear(SafeDateTime(datetime).Year);

        /// <summary>获取指定年月的天数。</summary>
        public static int MonthDays(int year, int month)
        {
            switch (month)
            {
                case 1: case 3: case 5: case 7: case 8: case 10: case 12: return 31;
                case 4: case 6: case 9: case 11: return 30;
                case 2: return IsLeapYear(year) ? 29 : 28;
                default: return 0;
            }
        }

        /// <summary>尝试获取安全的 DateTime 对象。</summary>
        public static DateTime SafeDateTime(object datetime)
        {
            if (datetime is DateTime)
            {
                var span = (DateTime)datetime - Origin;
                return Origin.AddMilliseconds(span.TotalMilliseconds);
            }
            else
            {
                if (datetime == null) return Zero;
                var type = datetime.GetType();
                if (type.Equals(typeof(string)))
                {
                    var s = datetime as string;
                    if (string.IsNullOrEmpty(s)) return Zero;
                    DateTime value;
                    var success = TryParse(s, out value);
                    return success ? value : Zero;
                }
                else
                {
                    if (datetime == null) return Zero;
                    try
                    {
                        var s = datetime.ToString();
                        if (string.IsNullOrEmpty(s)) return Zero;
                        return SafeDateTime(s);
                    }
                    catch { return Zero; }
                }
            }
        }

        #endregion

        #region Stamp

        /// <summary>获取当前本地时间的毫秒时间戳。</summary>
        public static long NowStamp { get => Stamp(Now); }

        /// <summary>获取当前 UTC 的毫秒时间戳。</summary>
        public static long UtcStamp { get => Stamp(UtcNow); }

        /// <summary>获取毫秒时间戳。</summary>
        public static long Stamp(DateTime datetime, bool byMilliseconds = true)
        {
            var span = datetime - Origin;
            var value = byMilliseconds ? span.TotalMilliseconds : span.TotalSeconds;
            var stamp = Convert.ToInt64(value);
            return stamp;
        }

        /// <summary>从毫秒时间戳获取 DateTime 对象。发生异常且不允许异常时将返回 1970-01-01 00:00:00.000。</summary>
        /// <exception cref="ArgumentOutOfRangeException"></exception>
        public static DateTime FromStamp(long stamp, DateTimeKind kind = DateTimeKind.Unspecified, bool throwException = true)
        {
            try
            {
                var origin = NewOrigin(kind);
                var datetime = origin.AddMilliseconds(Convert.ToDouble(stamp));
                return datetime;
            }
            catch
            {
                if (throwException) throw new ArgumentOutOfRangeException();
                return Origin;
            }
        }

        #endregion

        #region Text

        /// <summary>解析文本，获取 DateTime 对象。</summary>
        public static Class<DateTime> FromText(string text)
        {
            var str = text;
            if (string.IsNullOrEmpty(str)) return null;

            var utc = false;
            var lower = str.ToLower();
            if (lower.EndsWith(" utc"))
            {
                utc = true;
                str = str.Substring(0, str.Length - 4);
            }

            DateTime dt;
            if (!TryParse(str, out dt))
            {
                if (!str.Contains("-") && TryParseExact(str, "yyyy-M-d", null, DateTimeStyles.None, out dt))
                {
                    if (!str.Contains("/") && TryParseExact(str, "yyyy/M/d", null, DateTimeStyles.None, out dt))
                    {
                        return null;
                    }
                }
            }

            if (utc) dt = new DateTime(dt.Ticks, DateTimeKind.Utc);
            return new Class<DateTime>(dt);
        }

        #endregion

        #region Lucid & Compact

        /// <summary>表示当前本地时间的文本，显示为易于阅读的格式。</summary>
        public static string LucidNow { get => Lucid(Now); }

        /// <summary>表示当前 UTC 的文本，显示为易于阅读的格式。</summary>
        public static string LucidUtc { get => Lucid(UtcNow); }

        /// <summary>表示当前本地日期的文本，显示为易于阅读的格式。</summary>
        public static string LucidDate { get { return Lucid(Now, true, false, false, false); } }

        /// <summary>表示当前本地时间的文本，显示为紧凑的格式。</summary>
        public static string CompactNow { get => Compact(Now); }

        /// <summary>表示当前 UTC 的文本，显示为紧凑的格式。</summary>
        public static string CompactUtc { get => Compact(UtcNow); }

        /// <summary>表示当前本地日期的文本，显示为紧凑的格式。</summary>
        public static string CompactDate { get { return Compact(Now, true, false, false, false); } }

        /// <summary>转换 DateTime 对象到易于阅读的文本。</summary>
        public static string Lucid(DateTime datetime, bool date = true, bool time = true, bool seconds = true, bool milliseconds = true)
        {
            var safe = SafeDateTime(datetime);
            var sb = new StringBuilder();
            if (date) sb.Append(FormatDate(safe, true));
            if (time)
            {
                if (date) sb.Append(" ");
                sb.Append(FormatTime(safe, true, seconds, milliseconds));
            }
            var lucid = sb.ToString();
            return lucid;
        }

        /// <summary>转换 DateTime 对象到紧凑的文本。</summary>
        public static string Compact(DateTime datetime, bool date = true, bool time = true, bool seconds = true, bool milliseconds = true)
        {
            var safe = SafeDateTime(datetime);
            var sb = new StringBuilder();
            if (date) sb.Append(FormatDate(safe, false));
            if (time)
            {
                sb.Append(FormatTime(safe, false, seconds, milliseconds));
            }
            var lucid = sb.ToString();
            return lucid;
        }

        private static string FormatDate(DateTime datetime, bool lucid)
        {
            var sb = new StringBuilder();

            var y = NumberUtility.Restrict(datetime.Year, 0, 9999);
            var m = NumberUtility.Restrict(datetime.Month, 1, 12);
            var d = NumberUtility.Restrict(datetime.Day, 1, MonthDays(y, m));

            if (y < 10) sb.Append("000");
            else if (y < 100) sb.Append("00");
            else if (y < 1000) sb.Append("0");
            sb.Append(y.ToString());

            if (lucid) sb.Append("-");

            if (m < 10) sb.Append("0");
            sb.Append(m.ToString());

            if (lucid) sb.Append("-");

            if (d < 10) sb.Append("0");
            sb.Append(d.ToString());

            var date = sb.ToString();
            return date;
        }

        private static string FormatTime(DateTime datetime, bool lucid, bool seconds, bool milliseconds)
        {
            var sb = new StringBuilder();

            var h = NumberUtility.Restrict(datetime.Hour, 0, 23);
            var m = NumberUtility.Restrict(datetime.Minute, 0, 59);
            var s = NumberUtility.Restrict(datetime.Second, 0, 59);
            var ms = NumberUtility.Restrict(datetime.Millisecond, 0, 999);

            if (h < 10) sb.Append("0");
            sb.Append(h.ToString());

            if (lucid) sb.Append(":");

            if (m < 10) sb.Append("0");
            sb.Append(m.ToString());

            if (seconds)
            {
                if (lucid) sb.Append(":");

                if (s < 10) sb.Append("0");
                sb.Append(s.ToString());

                if (milliseconds)
                {
                    if (lucid) sb.Append(".");
                    if (ms < 10) sb.Append("00");
                    else if (ms < 100) sb.Append("0");
                    sb.Append(ms.ToString());
                }
            }

            var time = sb.ToString();
            return time;
        }

        /// <summary>解析文本。</summary>
        /// <param name="text">要被解析的文本。</param>
        /// <param name="failed">解析失败时的获取方法。</param>
        public static Nullable<DateTime> Parse(string text, Func<DateTime> failed = null)
        {
            if (string.IsNullOrEmpty(text)) return null;

            // 使用默认解析。
            {
                if (TryParse(text, out DateTime dt)) return dt;
            }

            // 尝试解析 Lucid 格式。
            var byLucid = ParseLucid(text);
            if (byLucid != null) return byLucid;

            // 尝试 failed 回调。
            if (failed != null) return failed.Invoke();

            return null;
        }

        /// <summary>解析文本。</summary>
        public static Nullable<DateTime> ParseLucid(string lucid)
        {
            var failed = null as Nullable<DateTime>;
            if (lucid.IsEmpty()) return failed;

            int year = 0, month = 0, day = 0;
            if (lucid.Length < 10) return failed;
            if (lucid[4] != '-' || lucid[7] != '-') return failed;
            year = NumberUtility.Int32(lucid.Substring(0, 4));
            month = NumberUtility.Int32(lucid.Substring(5, 2));
            day = NumberUtility.Int32(lucid.Substring(8, 2));
            if (year < 1) return failed;
            if (month < 1 || month > 12) return failed;
            if (day < 1 || day > DaysInMonth(year, month)) return failed;

            int hour = 0, minute = 0, second = 0, milli = 0;
            if (lucid.Length >= 16)
            {
                if (lucid[10] != ' ' || lucid[13] != ':') return failed;
                hour = NumberUtility.Int32(lucid.Substring(11, 2));
                minute = NumberUtility.Int32(lucid.Substring(14, 2));
                if (hour < 0 || hour > 23) return failed;
                if (minute < 0 || minute > 59) return failed;

                if (lucid.Length >= 19)
                {
                    if (lucid[16] != ':') return failed;
                    second = NumberUtility.Int32(lucid.Substring(17, 2));
                    if (second < 0 || second > 59) return failed;

                    if (lucid.Length >= 23)
                    {
                        if (lucid[19] != '.') return failed;
                        milli = NumberUtility.Int32(lucid.Substring(20, 3));
                        if (milli < 0 || milli > 999) return failed;
                    }
                }
            }

            var entity = new DateTime(year, month, day, hour, minute, second, milli);
            return new Nullable<DateTime>(entity);
        }

        #endregion

    }

}