1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
//! The [`UtcOffset`] struct and its associated `impl`s.

use core::fmt;
use core::ops::Neg;
#[cfg(feature = "formatting")]
use std::io;

use crate::convert::*;
use crate::error;
#[cfg(feature = "formatting")]
use crate::formatting::Formattable;
#[cfg(feature = "parsing")]
use crate::parsing::Parsable;
#[cfg(feature = "local-offset")]
use crate::sys::local_offset_at;
#[cfg(feature = "local-offset")]
use crate::OffsetDateTime;

/// An offset from UTC.
///
/// This struct can store values up to ±23:59:59. If you need support outside this range, please
/// file an issue with your use case.
// All three components _must_ have the same sign.
#[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct UtcOffset {
    #[allow(clippy::missing_docs_in_private_items)]
    hours: i8,
    #[allow(clippy::missing_docs_in_private_items)]
    minutes: i8,
    #[allow(clippy::missing_docs_in_private_items)]
    seconds: i8,
}

impl UtcOffset {
    /// A `UtcOffset` that is UTC.
    ///
    /// ```rust
    /// # use time::UtcOffset;
    /// # use time_macros::offset;
    /// assert_eq!(UtcOffset::UTC, offset!(UTC));
    /// ```
    pub const UTC: Self = Self::__from_hms_unchecked(0, 0, 0);

    // region: constructors
    /// Create a `UtcOffset` representing an offset of the hours, minutes, and seconds provided, the
    /// validity of which must be guaranteed by the caller. All three parameters must have the same
    /// sign.
    #[doc(hidden)]
    pub const fn __from_hms_unchecked(hours: i8, minutes: i8, seconds: i8) -> Self {
        if hours < 0 {
            debug_assert!(minutes <= 0);
            debug_assert!(seconds <= 0);
        } else if hours > 0 {
            debug_assert!(minutes >= 0);
            debug_assert!(seconds >= 0);
        }
        if minutes < 0 {
            debug_assert!(seconds <= 0);
        } else if minutes > 0 {
            debug_assert!(seconds >= 0);
        }
        debug_assert!(hours.unsigned_abs() < 24);
        debug_assert!(minutes.unsigned_abs() < Minute.per(Hour));
        debug_assert!(seconds.unsigned_abs() < Second.per(Minute));

        Self {
            hours,
            minutes,
            seconds,
        }
    }

    /// Create a `UtcOffset` representing an offset by the number of hours, minutes, and seconds
    /// provided.
    ///
    /// The sign of all three components should match. If they do not, all smaller components will
    /// have their signs flipped.
    ///
    /// ```rust
    /// # use time::UtcOffset;
    /// assert_eq!(UtcOffset::from_hms(1, 2, 3)?.as_hms(), (1, 2, 3));
    /// assert_eq!(UtcOffset::from_hms(1, -2, -3)?.as_hms(), (1, 2, 3));
    /// # Ok::<_, time::Error>(())
    /// ```
    pub const fn from_hms(
        hours: i8,
        mut minutes: i8,
        mut seconds: i8,
    ) -> Result<Self, error::ComponentRange> {
        ensure_value_in_range!(hours in -23 => 23);
        ensure_value_in_range!(
            minutes in -(Minute.per(Hour) as i8 - 1) => Minute.per(Hour) as i8 - 1
        );
        ensure_value_in_range!(
            seconds in -(Second.per(Minute) as i8 - 1) => Second.per(Minute) as i8 - 1
        );

        if (hours > 0 && minutes < 0) || (hours < 0 && minutes > 0) {
            minutes *= -1;
        }
        if (hours > 0 && seconds < 0)
            || (hours < 0 && seconds > 0)
            || (minutes > 0 && seconds < 0)
            || (minutes < 0 && seconds > 0)
        {
            seconds *= -1;
        }

        Ok(Self::__from_hms_unchecked(hours, minutes, seconds))
    }

    /// Create a `UtcOffset` representing an offset by the number of seconds provided.
    ///
    /// ```rust
    /// # use time::UtcOffset;
    /// assert_eq!(UtcOffset::from_whole_seconds(3_723)?.as_hms(), (1, 2, 3));
    /// # Ok::<_, time::Error>(())
    /// ```
    pub const fn from_whole_seconds(seconds: i32) -> Result<Self, error::ComponentRange> {
        ensure_value_in_range!(
            seconds in -24 * Second.per(Hour) as i32 - 1 => 24 * Second.per(Hour) as i32 - 1
        );

        Ok(Self::__from_hms_unchecked(
            (seconds / Second.per(Hour) as i32) as _,
            ((seconds % Second.per(Hour) as i32) / Minute.per(Hour) as i32) as _,
            (seconds % Second.per(Minute) as i32) as _,
        ))
    }
    // endregion constructors

    // region: getters
    /// Obtain the UTC offset as its hours, minutes, and seconds. The sign of all three components
    /// will always match. A positive value indicates an offset to the east; a negative to the west.
    ///
    /// ```rust
    /// # use time_macros::offset;
    /// assert_eq!(offset!(+1:02:03).as_hms(), (1, 2, 3));
    /// assert_eq!(offset!(-1:02:03).as_hms(), (-1, -2, -3));
    /// ```
    pub const fn as_hms(self) -> (i8, i8, i8) {
        (self.hours, self.minutes, self.seconds)
    }

    /// Obtain the number of whole hours the offset is from UTC. A positive value indicates an
    /// offset to the east; a negative to the west.
    ///
    /// ```rust
    /// # use time_macros::offset;
    /// assert_eq!(offset!(+1:02:03).whole_hours(), 1);
    /// assert_eq!(offset!(-1:02:03).whole_hours(), -1);
    /// ```
    pub const fn whole_hours(self) -> i8 {
        self.hours
    }

    /// Obtain the number of whole minutes the offset is from UTC. A positive value indicates an
    /// offset to the east; a negative to the west.
    ///
    /// ```rust
    /// # use time_macros::offset;
    /// assert_eq!(offset!(+1:02:03).whole_minutes(), 62);
    /// assert_eq!(offset!(-1:02:03).whole_minutes(), -62);
    /// ```
    pub const fn whole_minutes(self) -> i16 {
        self.hours as i16 * Minute.per(Hour) as i16 + self.minutes as i16
    }

    /// Obtain the number of minutes past the hour the offset is from UTC. A positive value
    /// indicates an offset to the east; a negative to the west.
    ///
    /// ```rust
    /// # use time_macros::offset;
    /// assert_eq!(offset!(+1:02:03).minutes_past_hour(), 2);
    /// assert_eq!(offset!(-1:02:03).minutes_past_hour(), -2);
    /// ```
    pub const fn minutes_past_hour(self) -> i8 {
        self.minutes
    }

    /// Obtain the number of whole seconds the offset is from UTC. A positive value indicates an
    /// offset to the east; a negative to the west.
    ///
    /// ```rust
    /// # use time_macros::offset;
    /// assert_eq!(offset!(+1:02:03).whole_seconds(), 3723);
    /// assert_eq!(offset!(-1:02:03).whole_seconds(), -3723);
    /// ```
    // This may be useful for anyone manually implementing arithmetic, as it
    // would let them construct a `Duration` directly.
    pub const fn whole_seconds(self) -> i32 {
        self.hours as i32 * Second.per(Hour) as i32
            + self.minutes as i32 * Second.per(Minute) as i32
            + self.seconds as i32
    }

    /// Obtain the number of seconds past the minute the offset is from UTC. A positive value
    /// indicates an offset to the east; a negative to the west.
    ///
    /// ```rust
    /// # use time_macros::offset;
    /// assert_eq!(offset!(+1:02:03).seconds_past_minute(), 3);
    /// assert_eq!(offset!(-1:02:03).seconds_past_minute(), -3);
    /// ```
    pub const fn seconds_past_minute(self) -> i8 {
        self.seconds
    }
    // endregion getters

    // region: is_{sign}
    /// Check if the offset is exactly UTC.
    ///
    ///
    /// ```rust
    /// # use time_macros::offset;
    /// assert!(!offset!(+1:02:03).is_utc());
    /// assert!(!offset!(-1:02:03).is_utc());
    /// assert!(offset!(UTC).is_utc());
    /// ```
    pub const fn is_utc(self) -> bool {
        self.hours == 0 && self.minutes == 0 && self.seconds == 0
    }

    /// Check if the offset is positive, or east of UTC.
    ///
    /// ```rust
    /// # use time_macros::offset;
    /// assert!(offset!(+1:02:03).is_positive());
    /// assert!(!offset!(-1:02:03).is_positive());
    /// assert!(!offset!(UTC).is_positive());
    /// ```
    pub const fn is_positive(self) -> bool {
        self.hours > 0 || self.minutes > 0 || self.seconds > 0
    }

    /// Check if the offset is negative, or west of UTC.
    ///
    /// ```rust
    /// # use time_macros::offset;
    /// assert!(!offset!(+1:02:03).is_negative());
    /// assert!(offset!(-1:02:03).is_negative());
    /// assert!(!offset!(UTC).is_negative());
    /// ```
    pub const fn is_negative(self) -> bool {
        self.hours < 0 || self.minutes < 0 || self.seconds < 0
    }
    // endregion is_{sign}

    // region: local offset
    /// Attempt to obtain the system's UTC offset at a known moment in time. If the offset cannot be
    /// determined, an error is returned.
    ///
    /// ```rust
    /// # use time::{UtcOffset, OffsetDateTime};
    /// let local_offset = UtcOffset::local_offset_at(OffsetDateTime::UNIX_EPOCH);
    /// # if false {
    /// assert!(local_offset.is_ok());
    /// # }
    /// ```
    #[cfg(feature = "local-offset")]
    pub fn local_offset_at(datetime: OffsetDateTime) -> Result<Self, error::IndeterminateOffset> {
        local_offset_at(datetime).ok_or(error::IndeterminateOffset)
    }

    /// Attempt to obtain the system's current UTC offset. If the offset cannot be determined, an
    /// error is returned.
    ///
    /// ```rust
    /// # use time::UtcOffset;
    /// let local_offset = UtcOffset::current_local_offset();
    /// # if false {
    /// assert!(local_offset.is_ok());
    /// # }
    /// ```
    #[cfg(feature = "local-offset")]
    pub fn current_local_offset() -> Result<Self, error::IndeterminateOffset> {
        let now = OffsetDateTime::now_utc();
        local_offset_at(now).ok_or(error::IndeterminateOffset)
    }
    // endregion: local offset
}

// region: formatting & parsing
#[cfg(feature = "formatting")]
impl UtcOffset {
    /// Format the `UtcOffset` using the provided [format description](crate::format_description).
    pub fn format_into(
        self,
        output: &mut impl io::Write,
        format: &(impl Formattable + ?Sized),
    ) -> Result<usize, error::Format> {
        format.format_into(output, None, None, Some(self))
    }

    /// Format the `UtcOffset` using the provided [format description](crate::format_description).
    ///
    /// ```rust
    /// # use time::format_description;
    /// # use time_macros::offset;
    /// let format = format_description::parse("[offset_hour sign:mandatory]:[offset_minute]")?;
    /// assert_eq!(offset!(+1).format(&format)?, "+01:00");
    /// # Ok::<_, time::Error>(())
    /// ```
    pub fn format(self, format: &(impl Formattable + ?Sized)) -> Result<String, error::Format> {
        format.format(None, None, Some(self))
    }
}

#[cfg(feature = "parsing")]
impl UtcOffset {
    /// Parse a `UtcOffset` from the input using the provided [format
    /// description](crate::format_description).
    ///
    /// ```rust
    /// # use time::UtcOffset;
    /// # use time_macros::{offset, format_description};
    /// let format = format_description!("[offset_hour]:[offset_minute]");
    /// assert_eq!(UtcOffset::parse("-03:42", &format)?, offset!(-3:42));
    /// # Ok::<_, time::Error>(())
    /// ```
    pub fn parse(
        input: &str,
        description: &(impl Parsable + ?Sized),
    ) -> Result<Self, error::Parse> {
        description.parse_offset(input.as_bytes())
    }
}

impl fmt::Display for UtcOffset {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(
            f,
            "{}{:02}:{:02}:{:02}",
            if self.is_negative() { '-' } else { '+' },
            self.hours.abs(),
            self.minutes.abs(),
            self.seconds.abs()
        )
    }
}

impl fmt::Debug for UtcOffset {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt::Display::fmt(self, f)
    }
}
// endregion formatting & parsing

impl Neg for UtcOffset {
    type Output = Self;

    fn neg(self) -> Self::Output {
        Self::__from_hms_unchecked(-self.hours, -self.minutes, -self.seconds)
    }
}