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
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
#![deny(missing_docs)]
#![deny(non_upper_case_globals)]
#![deny(non_camel_case_types)]
#![deny(non_snake_case)]
#![deny(unused_mut)]
#![deny(broken_intra_doc_links)]

#![cfg_attr(docsrs, feature(doc_auto_cfg))]

#![cfg_attr(feature = "strict", deny(warnings))]
#![cfg_attr(all(not(feature = "std"), not(test)), no_std)]

//! This crate provides data structures to represent
//! [lightning BOLT11](https://github.com/lightning/bolts/blob/master/11-payment-encoding.md)
//! invoices and functions to create, encode and decode these. If you just want to use the standard
//! en-/decoding functionality this should get you started:
//!
//!   * For parsing use `str::parse::<Invoice>(&self)` (see the docs of `impl FromStr for Invoice`)
//!   * For constructing invoices use the `InvoiceBuilder`
//!   * For serializing invoices use the `Display`/`ToString` traits

#[cfg(not(any(feature = "std", feature = "no-std")))]
compile_error!("at least one of the `std` or `no-std` features must be enabled");

pub mod payment;
pub mod utils;

pub(crate) mod time_utils;

extern crate bech32;
extern crate bitcoin_hashes;
#[macro_use] extern crate lightning;
extern crate num_traits;
extern crate secp256k1;
extern crate alloc;
#[cfg(any(test, feature = "std"))]
extern crate core;
#[cfg(feature = "serde")]
extern crate serde;

#[cfg(feature = "std")]
use std::time::SystemTime;

use bech32::u5;
use bitcoin_hashes::Hash;
use bitcoin_hashes::sha256;
use lightning::ln::PaymentSecret;
use lightning::ln::features::InvoiceFeatures;
#[cfg(any(doc, test))]
use lightning::routing::gossip::RoutingFees;
use lightning::routing::router::RouteHint;
use lightning::util::invoice::construct_invoice_preimage;

use secp256k1::PublicKey;
use secp256k1::{Message, Secp256k1};
use secp256k1::ecdsa::RecoverableSignature;

use core::fmt::{Display, Formatter, self};
use core::iter::FilterMap;
use core::num::ParseIntError;
use core::ops::Deref;
use core::slice::Iter;
use core::time::Duration;
use core::str;

#[cfg(feature = "serde")]
use serde::{Deserialize, Deserializer,Serialize, Serializer, de::Error};

mod de;
mod ser;
mod tb;

mod prelude {
	#[cfg(feature = "hashbrown")]
	extern crate hashbrown;

	pub use alloc::{vec, vec::Vec, string::String, collections::VecDeque, boxed::Box};
	#[cfg(not(feature = "hashbrown"))]
	pub use std::collections::{HashMap, HashSet, hash_map};
	#[cfg(feature = "hashbrown")]
	pub use self::hashbrown::{HashMap, HashSet, hash_map};

	pub use alloc::string::ToString;
}

use prelude::*;

/// Sync compat for std/no_std
#[cfg(feature = "std")]
mod sync {
	pub use ::std::sync::{Mutex, MutexGuard};
}

/// Sync compat for std/no_std
#[cfg(not(feature = "std"))]
mod sync;

/// Errors that indicate what is wrong with the invoice. They have some granularity for debug
/// reasons, but should generally result in an "invalid BOLT11 invoice" message for the user.
#[allow(missing_docs)]
#[derive(PartialEq, Debug, Clone)]
pub enum ParseError {
	Bech32Error(bech32::Error),
	ParseAmountError(ParseIntError),
	MalformedSignature(secp256k1::Error),
	BadPrefix,
	UnknownCurrency,
	UnknownSiPrefix,
	MalformedHRP,
	TooShortDataPart,
	UnexpectedEndOfTaggedFields,
	DescriptionDecodeError(str::Utf8Error),
	PaddingError,
	IntegerOverflowError,
	InvalidSegWitProgramLength,
	InvalidPubKeyHashLength,
	InvalidScriptHashLength,
	InvalidRecoveryId,
	InvalidSliceLength(String),

	/// Not an error, but used internally to signal that a part of the invoice should be ignored
	/// according to BOLT11
	Skip,
}

/// Indicates that something went wrong while parsing or validating the invoice. Parsing errors
/// should be mostly seen as opaque and are only there for debugging reasons. Semantic errors
/// like wrong signatures, missing fields etc. could mean that someone tampered with the invoice.
#[derive(PartialEq, Debug, Clone)]
pub enum ParseOrSemanticError {
	/// The invoice couldn't be decoded
	ParseError(ParseError),

	/// The invoice could be decoded but violates the BOLT11 standard
	SemanticError(::SemanticError),
}

/// The number of bits used to represent timestamps as defined in BOLT 11.
const TIMESTAMP_BITS: usize = 35;

/// The maximum timestamp as [`Duration::as_secs`] since the Unix epoch allowed by [`BOLT 11`].
///
/// [BOLT 11]: https://github.com/lightning/bolts/blob/master/11-payment-encoding.md
pub const MAX_TIMESTAMP: u64 = (1 << TIMESTAMP_BITS) - 1;

/// Default expiry time as defined by [BOLT 11].
///
/// [BOLT 11]: https://github.com/lightning/bolts/blob/master/11-payment-encoding.md
pub const DEFAULT_EXPIRY_TIME: u64 = 3600;

/// Default minimum final CLTV expiry as defined by [BOLT 11].
///
/// Note that this is *not* the same value as rust-lightning's minimum CLTV expiry, which is
/// provided in [`MIN_FINAL_CLTV_EXPIRY`].
///
/// [BOLT 11]: https://github.com/lightning/bolts/blob/master/11-payment-encoding.md
/// [`MIN_FINAL_CLTV_EXPIRY`]: lightning::ln::channelmanager::MIN_FINAL_CLTV_EXPIRY
pub const DEFAULT_MIN_FINAL_CLTV_EXPIRY: u64 = 18;

/// Builder for `Invoice`s. It's the most convenient and advised way to use this library. It ensures
/// that only a semantically and syntactically correct Invoice can be built using it.
///
/// ```
/// extern crate secp256k1;
/// extern crate lightning;
/// extern crate lightning_invoice;
/// extern crate bitcoin_hashes;
///
/// use bitcoin_hashes::Hash;
/// use bitcoin_hashes::sha256;
///
/// use secp256k1::Secp256k1;
/// use secp256k1::SecretKey;
///
/// use lightning::ln::PaymentSecret;
///
/// use lightning_invoice::{Currency, InvoiceBuilder};
///
/// # #[cfg(not(feature = "std"))]
/// # fn main() {}
/// # #[cfg(feature = "std")]
/// # fn main() {
/// let private_key = SecretKey::from_slice(
///		&[
///			0xe1, 0x26, 0xf6, 0x8f, 0x7e, 0xaf, 0xcc, 0x8b, 0x74, 0xf5, 0x4d, 0x26, 0x9f,
///			0xe2, 0x06, 0xbe, 0x71, 0x50, 0x00, 0xf9, 0x4d, 0xac, 0x06, 0x7d, 0x1c, 0x04,
/// 		0xa8, 0xca, 0x3b, 0x2d, 0xb7, 0x34
/// 	][..]
///	).unwrap();
///
/// let payment_hash = sha256::Hash::from_slice(&[0; 32][..]).unwrap();
/// let payment_secret = PaymentSecret([42u8; 32]);
///
/// let invoice = InvoiceBuilder::new(Currency::Bitcoin)
/// 	.description("Coins pls!".into())
/// 	.payment_hash(payment_hash)
/// 	.payment_secret(payment_secret)
/// 	.current_timestamp()
/// 	.min_final_cltv_expiry(144)
/// 	.build_signed(|hash| {
/// 		Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key)
/// 	})
/// 	.unwrap();
///
/// assert!(invoice.to_string().starts_with("lnbc1"));
/// # }
/// ```
///
/// # Type parameters
/// The two parameters `D` and `H` signal if the builder already contains the correct amount of the
/// given field:
///  * `D`: exactly one `Description` or `DescriptionHash`
///  * `H`: exactly one `PaymentHash`
///  * `T`: the timestamp is set
///
/// (C-not exported) as we likely need to manually select one set of boolean type parameters.
#[derive(Eq, PartialEq, Debug, Clone)]
pub struct InvoiceBuilder<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> {
	currency: Currency,
	amount: Option<u64>,
	si_prefix: Option<SiPrefix>,
	timestamp: Option<PositiveTimestamp>,
	tagged_fields: Vec<TaggedField>,
	error: Option<CreationError>,

	phantom_d: core::marker::PhantomData<D>,
	phantom_h: core::marker::PhantomData<H>,
	phantom_t: core::marker::PhantomData<T>,
	phantom_c: core::marker::PhantomData<C>,
	phantom_s: core::marker::PhantomData<S>,
}

/// Represents a syntactically and semantically correct lightning BOLT11 invoice.
///
/// There are three ways to construct an `Invoice`:
///  1. using `InvoiceBuilder`
///  2. using `Invoice::from_signed(SignedRawInvoice)`
///  3. using `str::parse::<Invoice>(&str)`
#[derive(Eq, PartialEq, Debug, Clone)]
pub struct Invoice {
	signed_invoice: SignedRawInvoice,
}

/// Represents the description of an invoice which has to be either a directly included string or
/// a hash of a description provided out of band.
///
/// (C-not exported) As we don't have a good way to map the reference lifetimes making this
/// practically impossible to use safely in languages like C.
#[derive(Eq, PartialEq, Debug, Clone)]
pub enum InvoiceDescription<'f> {
	/// Reference to the directly supplied description in the invoice
	Direct(&'f Description),

	/// Reference to the description's hash included in the invoice
	Hash(&'f Sha256),
}

/// Represents a signed `RawInvoice` with cached hash. The signature is not checked and may be
/// invalid.
///
/// # Invariants
/// The hash has to be either from the deserialized invoice or from the serialized `raw_invoice`.
#[derive(Eq, PartialEq, Debug, Clone)]
pub struct SignedRawInvoice {
	/// The rawInvoice that the signature belongs to
	raw_invoice: RawInvoice,

	/// Hash of the `RawInvoice` that will be used to check the signature.
	///
	/// * if the `SignedRawInvoice` was deserialized the hash is of from the original encoded form,
	/// since it's not guaranteed that encoding it again will lead to the same result since integers
	/// could have been encoded with leading zeroes etc.
	/// * if the `SignedRawInvoice` was constructed manually the hash will be the calculated hash
	/// from the `RawInvoice`
	hash: [u8; 32],

	/// signature of the payment request
	signature: InvoiceSignature,
}

/// Represents an syntactically correct Invoice for a payment on the lightning network,
/// but without the signature information.
/// De- and encoding should not lead to information loss but may lead to different hashes.
///
/// For methods without docs see the corresponding methods in `Invoice`.
#[derive(Eq, PartialEq, Debug, Clone)]
pub struct RawInvoice {
	/// human readable part
	pub hrp: RawHrp,

	/// data part
	pub data: RawDataPart,
}

/// Data of the `RawInvoice` that is encoded in the human readable part
///
/// (C-not exported) As we don't yet support Option<Enum>
#[derive(Eq, PartialEq, Debug, Clone)]
pub struct RawHrp {
	/// The currency deferred from the 3rd and 4th character of the bech32 transaction
	pub currency: Currency,

	/// The amount that, multiplied by the SI prefix, has to be payed
	pub raw_amount: Option<u64>,

	/// SI prefix that gets multiplied with the `raw_amount`
	pub si_prefix: Option<SiPrefix>,
}

/// Data of the `RawInvoice` that is encoded in the data part
#[derive(Eq, PartialEq, Debug, Clone)]
pub struct RawDataPart {
	/// generation time of the invoice
	pub timestamp: PositiveTimestamp,

	/// tagged fields of the payment request
	pub tagged_fields: Vec<RawTaggedField>,
}

/// A timestamp that refers to a date after 1 January 1970.
///
/// # Invariants
///
/// The Unix timestamp representing the stored time has to be positive and no greater than
/// [`MAX_TIMESTAMP`].
#[derive(Eq, PartialEq, Debug, Clone)]
pub struct PositiveTimestamp(Duration);

/// SI prefixes for the human readable part
#[derive(Eq, PartialEq, Debug, Clone, Copy)]
pub enum SiPrefix {
	/// 10^-3
	Milli,
	/// 10^-6
	Micro,
	/// 10^-9
	Nano,
	/// 10^-12
	Pico,
}

impl SiPrefix {
	/// Returns the multiplier to go from a BTC value to picoBTC implied by this SiPrefix.
	/// This is effectively 10^12 * the prefix multiplier
	pub fn multiplier(&self) -> u64 {
		match *self {
			SiPrefix::Milli => 1_000_000_000,
			SiPrefix::Micro => 1_000_000,
			SiPrefix::Nano => 1_000,
			SiPrefix::Pico => 1,
		}
	}

	/// Returns all enum variants of `SiPrefix` sorted in descending order of their associated
	/// multiplier.
	///
	/// (C-not exported) As we don't yet support a slice of enums, and also because this function
	/// isn't the most critical to expose.
	pub fn values_desc() -> &'static [SiPrefix] {
		use SiPrefix::*;
		static VALUES: [SiPrefix; 4] = [Milli, Micro, Nano, Pico];
		&VALUES
	}
}

/// Enum representing the crypto currencies (or networks) supported by this library
#[derive(Clone, Debug, Hash, Eq, PartialEq)]
pub enum Currency {
	/// Bitcoin mainnet
	Bitcoin,

	/// Bitcoin testnet
	BitcoinTestnet,

	/// Bitcoin regtest
	Regtest,

	/// Bitcoin simnet
	Simnet,

	/// Bitcoin signet
	Signet,
}

/// Tagged field which may have an unknown tag
///
/// (C-not exported) as we don't currently support TaggedField
#[derive(Clone, Debug, Hash, Eq, PartialEq)]
pub enum RawTaggedField {
	/// Parsed tagged field with known tag
	KnownSemantics(TaggedField),
	/// tagged field which was not parsed due to an unknown tag or undefined field semantics
	UnknownSemantics(Vec<u5>),
}

/// Tagged field with known tag
///
/// For descriptions of the enum values please refer to the enclosed type's docs.
///
/// (C-not exported) As we don't yet support enum variants with the same name the struct contained
/// in the variant.
#[allow(missing_docs)]
#[derive(Clone, Debug, Hash, Eq, PartialEq)]
pub enum TaggedField {
	PaymentHash(Sha256),
	Description(Description),
	PayeePubKey(PayeePubKey),
	DescriptionHash(Sha256),
	ExpiryTime(ExpiryTime),
	MinFinalCltvExpiry(MinFinalCltvExpiry),
	Fallback(Fallback),
	PrivateRoute(PrivateRoute),
	PaymentSecret(PaymentSecret),
	Features(InvoiceFeatures),
}

/// SHA-256 hash
#[derive(Clone, Debug, Hash, Eq, PartialEq)]
pub struct Sha256(/// (C-not exported) as the native hash types are not currently mapped
	pub sha256::Hash);

/// Description string
///
/// # Invariants
/// The description can be at most 639 __bytes__ long
#[derive(Clone, Debug, Hash, Eq, PartialEq)]
pub struct Description(String);

/// Payee public key
#[derive(Clone, Debug, Hash, Eq, PartialEq)]
pub struct PayeePubKey(pub PublicKey);

/// Positive duration that defines when (relatively to the timestamp) in the future the invoice
/// expires
#[derive(Clone, Debug, Hash, Eq, PartialEq)]
pub struct ExpiryTime(Duration);

/// `min_final_cltv_expiry` to use for the last HTLC in the route
#[derive(Clone, Debug, Hash, Eq, PartialEq)]
pub struct MinFinalCltvExpiry(pub u64);

// TODO: better types instead onf byte arrays
/// Fallback address in case no LN payment is possible
#[allow(missing_docs)]
#[derive(Clone, Debug, Hash, Eq, PartialEq)]
pub enum Fallback {
	SegWitProgram {
		version: u5,
		program: Vec<u8>,
	},
	PubKeyHash([u8; 20]),
	ScriptHash([u8; 20]),
}

/// Recoverable signature
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct InvoiceSignature(pub RecoverableSignature);

/// Private routing information
///
/// # Invariants
/// The encoded route has to be <1024 5bit characters long (<=639 bytes or <=12 hops)
///
#[derive(Clone, Debug, Hash, Eq, PartialEq)]
pub struct PrivateRoute(RouteHint);

/// Tag constants as specified in BOLT11
#[allow(missing_docs)]
pub mod constants {
	pub const TAG_PAYMENT_HASH: u8 = 1;
	pub const TAG_DESCRIPTION: u8 = 13;
	pub const TAG_PAYEE_PUB_KEY: u8 = 19;
	pub const TAG_DESCRIPTION_HASH: u8 = 23;
	pub const TAG_EXPIRY_TIME: u8 = 6;
	pub const TAG_MIN_FINAL_CLTV_EXPIRY: u8 = 24;
	pub const TAG_FALLBACK: u8 = 9;
	pub const TAG_PRIVATE_ROUTE: u8 = 3;
	pub const TAG_PAYMENT_SECRET: u8 = 16;
	pub const TAG_FEATURES: u8 = 5;
}

impl InvoiceBuilder<tb::False, tb::False, tb::False, tb::False, tb::False> {
	/// Construct new, empty `InvoiceBuilder`. All necessary fields have to be filled first before
	/// `InvoiceBuilder::build(self)` becomes available.
	pub fn new(currrency: Currency) -> Self {
		InvoiceBuilder {
			currency: currrency,
			amount: None,
			si_prefix: None,
			timestamp: None,
			tagged_fields: Vec::new(),
			error: None,

			phantom_d: core::marker::PhantomData,
			phantom_h: core::marker::PhantomData,
			phantom_t: core::marker::PhantomData,
			phantom_c: core::marker::PhantomData,
			phantom_s: core::marker::PhantomData,
		}
	}
}

impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, H, T, C, S> {
	/// Helper function to set the completeness flags.
	fn set_flags<DN: tb::Bool, HN: tb::Bool, TN: tb::Bool, CN: tb::Bool, SN: tb::Bool>(self) -> InvoiceBuilder<DN, HN, TN, CN, SN> {
		InvoiceBuilder::<DN, HN, TN, CN, SN> {
			currency: self.currency,
			amount: self.amount,
			si_prefix: self.si_prefix,
			timestamp: self.timestamp,
			tagged_fields: self.tagged_fields,
			error: self.error,

			phantom_d: core::marker::PhantomData,
			phantom_h: core::marker::PhantomData,
			phantom_t: core::marker::PhantomData,
			phantom_c: core::marker::PhantomData,
			phantom_s: core::marker::PhantomData,
		}
	}

	/// Sets the amount in millisatoshis. The optimal SI prefix is chosen automatically.
	pub fn amount_milli_satoshis(mut self, amount_msat: u64) -> Self {
		let amount = amount_msat * 10; // Invoices are denominated in "pico BTC"
		let biggest_possible_si_prefix = SiPrefix::values_desc()
			.iter()
			.find(|prefix| amount % prefix.multiplier() == 0)
			.expect("Pico should always match");
		self.amount = Some(amount / biggest_possible_si_prefix.multiplier());
		self.si_prefix = Some(*biggest_possible_si_prefix);
		self
	}

	/// Sets the payee's public key.
	pub fn payee_pub_key(mut self, pub_key: PublicKey) -> Self {
		self.tagged_fields.push(TaggedField::PayeePubKey(PayeePubKey(pub_key)));
		self
	}

	/// Sets the expiry time
	pub fn expiry_time(mut self, expiry_time: Duration) -> Self {
		self.tagged_fields.push(TaggedField::ExpiryTime(ExpiryTime::from_duration(expiry_time)));
		self
	}

	/// Adds a fallback address.
	pub fn fallback(mut self, fallback: Fallback) -> Self {
		self.tagged_fields.push(TaggedField::Fallback(fallback));
		self
	}

	/// Adds a private route.
	pub fn private_route(mut self, hint: RouteHint) -> Self {
		match PrivateRoute::new(hint) {
			Ok(r) => self.tagged_fields.push(TaggedField::PrivateRoute(r)),
			Err(e) => self.error = Some(e),
		}
		self
	}
}

impl<D: tb::Bool, H: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, H, tb::True, C, S> {
	/// Builds a `RawInvoice` if no `CreationError` occurred while construction any of the fields.
	pub fn build_raw(self) -> Result<RawInvoice, CreationError> {

		// If an error occurred at any time before, return it now
		if let Some(e) = self.error {
			return Err(e);
		}

		let hrp = RawHrp {
			currency: self.currency,
			raw_amount: self.amount,
			si_prefix: self.si_prefix,
		};

		let timestamp = self.timestamp.expect("ensured to be Some(t) by type T");

		let tagged_fields = self.tagged_fields.into_iter().map(|tf| {
			RawTaggedField::KnownSemantics(tf)
		}).collect::<Vec<_>>();

		let data = RawDataPart {
			timestamp: timestamp,
			tagged_fields: tagged_fields,
		};

		Ok(RawInvoice {
			hrp: hrp,
			data: data,
		})
	}
}

impl<H: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<tb::False, H, T, C, S> {
	/// Set the description. This function is only available if no description (hash) was set.
	pub fn description(mut self, description: String) -> InvoiceBuilder<tb::True, H, T, C, S> {
		match Description::new(description) {
			Ok(d) => self.tagged_fields.push(TaggedField::Description(d)),
			Err(e) => self.error = Some(e),
		}
		self.set_flags()
	}

	/// Set the description hash. This function is only available if no description (hash) was set.
	pub fn description_hash(mut self, description_hash: sha256::Hash) -> InvoiceBuilder<tb::True, H, T, C, S> {
		self.tagged_fields.push(TaggedField::DescriptionHash(Sha256(description_hash)));
		self.set_flags()
	}
}

impl<D: tb::Bool, T: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, tb::False, T, C, S> {
	/// Set the payment hash. This function is only available if no payment hash was set.
	pub fn payment_hash(mut self, hash: sha256::Hash) -> InvoiceBuilder<D, tb::True, T, C, S> {
		self.tagged_fields.push(TaggedField::PaymentHash(Sha256(hash)));
		self.set_flags()
	}
}

impl<D: tb::Bool, H: tb::Bool, C: tb::Bool, S: tb::Bool> InvoiceBuilder<D, H, tb::False, C, S> {
	/// Sets the timestamp to a specific [`SystemTime`].
	#[cfg(feature = "std")]
	pub fn timestamp(mut self, time: SystemTime) -> InvoiceBuilder<D, H, tb::True, C, S> {
		match PositiveTimestamp::from_system_time(time) {
			Ok(t) => self.timestamp = Some(t),
			Err(e) => self.error = Some(e),
		}

		self.set_flags()
	}

	/// Sets the timestamp to a duration since the Unix epoch.
	pub fn duration_since_epoch(mut self, time: Duration) -> InvoiceBuilder<D, H, tb::True, C, S> {
		match PositiveTimestamp::from_duration_since_epoch(time) {
			Ok(t) => self.timestamp = Some(t),
			Err(e) => self.error = Some(e),
		}

		self.set_flags()
	}

	/// Sets the timestamp to the current system time.
	#[cfg(feature = "std")]
	pub fn current_timestamp(mut self) -> InvoiceBuilder<D, H, tb::True, C, S> {
		let now = PositiveTimestamp::from_system_time(SystemTime::now());
		self.timestamp = Some(now.expect("for the foreseeable future this shouldn't happen"));
		self.set_flags()
	}
}

impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, S: tb::Bool> InvoiceBuilder<D, H, T, tb::False, S> {
	/// Sets `min_final_cltv_expiry`.
	pub fn min_final_cltv_expiry(mut self, min_final_cltv_expiry: u64) -> InvoiceBuilder<D, H, T, tb::True, S> {
		self.tagged_fields.push(TaggedField::MinFinalCltvExpiry(MinFinalCltvExpiry(min_final_cltv_expiry)));
		self.set_flags()
	}
}

impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool> InvoiceBuilder<D, H, T, C, tb::False> {
	/// Sets the payment secret and relevant features.
	pub fn payment_secret(mut self, payment_secret: PaymentSecret) -> InvoiceBuilder<D, H, T, C, tb::True> {
		let mut features = InvoiceFeatures::empty();
		features.set_variable_length_onion_required();
		features.set_payment_secret_required();
		self.tagged_fields.push(TaggedField::PaymentSecret(payment_secret));
		self.tagged_fields.push(TaggedField::Features(features));
		self.set_flags()
	}
}

impl<D: tb::Bool, H: tb::Bool, T: tb::Bool, C: tb::Bool> InvoiceBuilder<D, H, T, C, tb::True> {
	/// Sets the `basic_mpp` feature as optional.
	pub fn basic_mpp(mut self) -> Self {
		for field in self.tagged_fields.iter_mut() {
			if let TaggedField::Features(f) = field {
				f.set_basic_mpp_optional();
			}
		}
		self
	}
}

impl InvoiceBuilder<tb::True, tb::True, tb::True, tb::True, tb::True> {
	/// Builds and signs an invoice using the supplied `sign_function`. This function MAY NOT fail
	/// and MUST produce a recoverable signature valid for the given hash and if applicable also for
	/// the included payee public key.
	pub fn build_signed<F>(self, sign_function: F) -> Result<Invoice, CreationError>
		where F: FnOnce(&Message) -> RecoverableSignature
	{
		let invoice = self.try_build_signed::<_, ()>(|hash| {
			Ok(sign_function(hash))
		});

		match invoice {
			Ok(i) => Ok(i),
			Err(SignOrCreationError::CreationError(e)) => Err(e),
			Err(SignOrCreationError::SignError(())) => unreachable!(),
		}
	}

	/// Builds and signs an invoice using the supplied `sign_function`. This function MAY fail with
	/// an error of type `E` and MUST produce a recoverable signature valid for the given hash and
	/// if applicable also for the included payee public key.
	pub fn try_build_signed<F, E>(self, sign_function: F) -> Result<Invoice, SignOrCreationError<E>>
		where F: FnOnce(&Message) -> Result<RecoverableSignature, E>
	{
		let raw = match self.build_raw() {
			Ok(r) => r,
			Err(e) => return Err(SignOrCreationError::CreationError(e)),
		};

		let signed = match raw.sign(sign_function) {
			Ok(s) => s,
			Err(e) => return Err(SignOrCreationError::SignError(e)),
		};

		let invoice = Invoice {
			signed_invoice: signed,
		};

		invoice.check_field_counts().expect("should be ensured by type signature of builder");
		invoice.check_feature_bits().expect("should be ensured by type signature of builder");
		invoice.check_amount().expect("should be ensured by type signature of builder");

		Ok(invoice)
	}
}


impl SignedRawInvoice {
	/// Disassembles the `SignedRawInvoice` into its three parts:
	///  1. raw invoice
	///  2. hash of the raw invoice
	///  3. signature
	pub fn into_parts(self) -> (RawInvoice, [u8; 32], InvoiceSignature) {
		(self.raw_invoice, self.hash, self.signature)
	}

	/// The `RawInvoice` which was signed.
	pub fn raw_invoice(&self) -> &RawInvoice {
		&self.raw_invoice
	}

	/// The hash of the `RawInvoice` that was signed.
	pub fn hash(&self) -> &[u8; 32] {
		&self.hash
	}

	/// InvoiceSignature for the invoice.
	pub fn signature(&self) -> &InvoiceSignature {
		&self.signature
	}

	/// Recovers the public key used for signing the invoice from the recoverable signature.
	pub fn recover_payee_pub_key(&self) -> Result<PayeePubKey, secp256k1::Error> {
		let hash = Message::from_slice(&self.hash[..])
			.expect("Hash is 32 bytes long, same as MESSAGE_SIZE");

		Ok(PayeePubKey(Secp256k1::new().recover_ecdsa(
			&hash,
			&self.signature
		)?))
	}

	/// Checks if the signature is valid for the included payee public key or if none exists if it's
	/// valid for the recovered signature (which should always be true?).
	pub fn check_signature(&self) -> bool {
		let included_pub_key = self.raw_invoice.payee_pub_key();

		let mut recovered_pub_key = Option::None;
		if recovered_pub_key.is_none() {
			let recovered = match self.recover_payee_pub_key() {
				Ok(pk) => pk,
				Err(_) => return false,
			};
			recovered_pub_key = Some(recovered);
		}

		let pub_key = included_pub_key.or_else(|| recovered_pub_key.as_ref())
			.expect("One is always present");

		let hash = Message::from_slice(&self.hash[..])
			.expect("Hash is 32 bytes long, same as MESSAGE_SIZE");

		let secp_context = Secp256k1::new();
		let verification_result = secp_context.verify_ecdsa(
			&hash,
			&self.signature.to_standard(),
			pub_key
		);

		match verification_result {
			Ok(()) => true,
			Err(_) => false,
		}
	}
}

/// Finds the first element of an enum stream of a given variant and extracts one member of the
/// variant. If no element was found `None` gets returned.
///
/// The following example would extract the first B.
///
/// enum Enum {
/// 	A(u8),
/// 	B(u16)
/// }
///
/// let elements = vec![Enum::A(1), Enum::A(2), Enum::B(3), Enum::A(4)];
///
/// assert_eq!(find_extract!(elements.iter(), Enum::B(x), x), Some(3u16));
macro_rules! find_extract {
	($iter:expr, $enm:pat, $enm_var:ident) => {
		find_all_extract!($iter, $enm, $enm_var).next()
	};
}

/// Finds the all elements of an enum stream of a given variant and extracts one member of the
/// variant through an iterator.
///
/// The following example would extract all A.
///
/// enum Enum {
/// 	A(u8),
/// 	B(u16)
/// }
///
/// let elements = vec![Enum::A(1), Enum::A(2), Enum::B(3), Enum::A(4)];
///
/// assert_eq!(
/// 	find_all_extract!(elements.iter(), Enum::A(x), x).collect::<Vec<u8>>(),
/// 	vec![1u8, 2u8, 4u8]
/// );
macro_rules! find_all_extract {
	($iter:expr, $enm:pat, $enm_var:ident) => {
		$iter.filter_map(|tf| match *tf {
			$enm => Some($enm_var),
			_ => None,
		})
	};
}

#[allow(missing_docs)]
impl RawInvoice {
	/// Hash the HRP as bytes and signatureless data part.
	fn hash_from_parts(hrp_bytes: &[u8], data_without_signature: &[u5]) -> [u8; 32] {
		let preimage = construct_invoice_preimage(hrp_bytes, data_without_signature);
		let mut hash: [u8; 32] = Default::default();
		hash.copy_from_slice(&sha256::Hash::hash(&preimage)[..]);
		hash
	}

	/// Calculate the hash of the encoded `RawInvoice`
	pub fn hash(&self) -> [u8; 32] {
		use bech32::ToBase32;

		RawInvoice::hash_from_parts(
			self.hrp.to_string().as_bytes(),
			&self.data.to_base32()
		)
	}

	/// Signs the invoice using the supplied `sign_function`. This function MAY fail with an error
	/// of type `E`. Since the signature of a `SignedRawInvoice` is not required to be valid there
	/// are no constraints regarding the validity of the produced signature.
	///
	/// (C-not exported) As we don't currently support passing function pointers into methods
	/// explicitly.
	pub fn sign<F, E>(self, sign_method: F) -> Result<SignedRawInvoice, E>
		where F: FnOnce(&Message) -> Result<RecoverableSignature, E>
	{
		let raw_hash = self.hash();
		let hash = Message::from_slice(&raw_hash[..])
			.expect("Hash is 32 bytes long, same as MESSAGE_SIZE");
		let signature = sign_method(&hash)?;

		Ok(SignedRawInvoice {
			raw_invoice: self,
			hash: raw_hash,
			signature: InvoiceSignature(signature),
		})
	}

	/// Returns an iterator over all tagged fields with known semantics.
	///
	/// (C-not exported) As there is not yet a manual mapping for a FilterMap
	pub fn known_tagged_fields(&self)
		-> FilterMap<Iter<RawTaggedField>, fn(&RawTaggedField) -> Option<&TaggedField>>
	{
		// For 1.14.0 compatibility: closures' types can't be written an fn()->() in the
		// function's type signature.
		// TODO: refactor once impl Trait is available
		fn match_raw(raw: &RawTaggedField) -> Option<&TaggedField> {
			match *raw {
				RawTaggedField::KnownSemantics(ref tf) => Some(tf),
				_ => None,
			}
		}

		self.data.tagged_fields.iter().filter_map(match_raw )
	}

	pub fn payment_hash(&self) -> Option<&Sha256> {
		find_extract!(self.known_tagged_fields(), TaggedField::PaymentHash(ref x), x)
	}

	pub fn description(&self) -> Option<&Description> {
		find_extract!(self.known_tagged_fields(), TaggedField::Description(ref x), x)
	}

	pub fn payee_pub_key(&self) -> Option<&PayeePubKey> {
		find_extract!(self.known_tagged_fields(), TaggedField::PayeePubKey(ref x), x)
	}

	pub fn description_hash(&self) -> Option<&Sha256> {
		find_extract!(self.known_tagged_fields(), TaggedField::DescriptionHash(ref x), x)
	}

	pub fn expiry_time(&self) -> Option<&ExpiryTime> {
		find_extract!(self.known_tagged_fields(), TaggedField::ExpiryTime(ref x), x)
	}

	pub fn min_final_cltv_expiry(&self) -> Option<&MinFinalCltvExpiry> {
		find_extract!(self.known_tagged_fields(), TaggedField::MinFinalCltvExpiry(ref x), x)
	}

	pub fn payment_secret(&self) -> Option<&PaymentSecret> {
		find_extract!(self.known_tagged_fields(), TaggedField::PaymentSecret(ref x), x)
	}

	pub fn features(&self) -> Option<&InvoiceFeatures> {
		find_extract!(self.known_tagged_fields(), TaggedField::Features(ref x), x)
	}

	/// (C-not exported) as we don't support Vec<&NonOpaqueType>
	pub fn fallbacks(&self) -> Vec<&Fallback> {
		find_all_extract!(self.known_tagged_fields(), TaggedField::Fallback(ref x), x).collect()
	}

	pub fn private_routes(&self) -> Vec<&PrivateRoute> {
		find_all_extract!(self.known_tagged_fields(), TaggedField::PrivateRoute(ref x), x).collect()
	}

	pub fn amount_pico_btc(&self) -> Option<u64> {
		self.hrp.raw_amount.map(|v| {
			v * self.hrp.si_prefix.as_ref().map_or(1_000_000_000_000, |si| { si.multiplier() })
		})
	}

	pub fn currency(&self) -> Currency {
		self.hrp.currency.clone()
	}
}

impl PositiveTimestamp {
	/// Creates a `PositiveTimestamp` from a Unix timestamp in the range `0..=MAX_TIMESTAMP`.
	///
	/// Otherwise, returns a [`CreationError::TimestampOutOfBounds`].
	pub fn from_unix_timestamp(unix_seconds: u64) -> Result<Self, CreationError> {
		Self::from_duration_since_epoch(Duration::from_secs(unix_seconds))
	}

	/// Creates a `PositiveTimestamp` from a [`SystemTime`] with a corresponding Unix timestamp in
	/// the range `0..=MAX_TIMESTAMP`.
	///
	/// Otherwise, returns a [`CreationError::TimestampOutOfBounds`].
	#[cfg(feature = "std")]
	pub fn from_system_time(time: SystemTime) -> Result<Self, CreationError> {
		time.duration_since(SystemTime::UNIX_EPOCH)
			.map(Self::from_duration_since_epoch)
			.unwrap_or(Err(CreationError::TimestampOutOfBounds))
	}

	/// Creates a `PositiveTimestamp` from a [`Duration`] since the Unix epoch in the range
	/// `0..=MAX_TIMESTAMP`.
	///
	/// Otherwise, returns a [`CreationError::TimestampOutOfBounds`].
	pub fn from_duration_since_epoch(duration: Duration) -> Result<Self, CreationError> {
		if duration.as_secs() <= MAX_TIMESTAMP {
			Ok(PositiveTimestamp(duration))
		} else {
			Err(CreationError::TimestampOutOfBounds)
		}
	}

	/// Returns the Unix timestamp representing the stored time
	pub fn as_unix_timestamp(&self) -> u64 {
		self.0.as_secs()
	}

	/// Returns the duration of the stored time since the Unix epoch
	pub fn as_duration_since_epoch(&self) -> Duration {
		self.0
	}

	/// Returns the [`SystemTime`] representing the stored time
	#[cfg(feature = "std")]
	pub fn as_time(&self) -> SystemTime {
		SystemTime::UNIX_EPOCH + self.0
	}
}

#[cfg(feature = "std")]
impl Into<SystemTime> for PositiveTimestamp {
	fn into(self) -> SystemTime {
		SystemTime::UNIX_EPOCH + self.0
	}
}

impl Invoice {
	/// Transform the `Invoice` into it's unchecked version
	pub fn into_signed_raw(self) -> SignedRawInvoice {
		self.signed_invoice
	}

	/// Check that all mandatory fields are present
	fn check_field_counts(&self) -> Result<(), SemanticError> {
		// "A writer MUST include exactly one p field […]."
		let payment_hash_cnt = self.tagged_fields().filter(|&tf| match *tf {
			TaggedField::PaymentHash(_) => true,
			_ => false,
		}).count();
		if payment_hash_cnt < 1 {
			return Err(SemanticError::NoPaymentHash);
		} else if payment_hash_cnt > 1 {
			return Err(SemanticError::MultiplePaymentHashes);
		}

		// "A writer MUST include either exactly one d or exactly one h field."
		let description_cnt = self.tagged_fields().filter(|&tf| match *tf {
			TaggedField::Description(_) | TaggedField::DescriptionHash(_) => true,
			_ => false,
		}).count();
		if  description_cnt < 1 {
			return Err(SemanticError::NoDescription);
		} else if description_cnt > 1 {
			return  Err(SemanticError::MultipleDescriptions);
		}

		self.check_payment_secret()?;

		Ok(())
	}

	/// Checks that there is exactly one payment secret field
	fn check_payment_secret(&self) -> Result<(), SemanticError> {
		// "A writer MUST include exactly one `s` field."
		let payment_secret_count = self.tagged_fields().filter(|&tf| match *tf {
			TaggedField::PaymentSecret(_) => true,
			_ => false,
		}).count();
		if payment_secret_count < 1 {
			return Err(SemanticError::NoPaymentSecret);
		} else if payment_secret_count > 1 {
			return Err(SemanticError::MultiplePaymentSecrets);
		}

		Ok(())
	}

	/// Check that amount is a whole number of millisatoshis
	fn check_amount(&self) -> Result<(), SemanticError> {
		if let Some(amount_pico_btc) = self.amount_pico_btc() {
			if amount_pico_btc % 10 != 0 {
				return Err(SemanticError::ImpreciseAmount);
			}
		}
		Ok(())
	}

	/// Check that feature bits are set as required
	fn check_feature_bits(&self) -> Result<(), SemanticError> {
		self.check_payment_secret()?;

		// "A writer MUST set an s field if and only if the payment_secret feature is set."
		// (this requirement has been since removed, and we now require the payment secret
		// feature bit always).
		let features = self.tagged_fields().find(|&tf| match *tf {
			TaggedField::Features(_) => true,
			_ => false,
		});
		match features {
			None => Err(SemanticError::InvalidFeatures),
			Some(TaggedField::Features(features)) => {
				if features.requires_unknown_bits() {
					Err(SemanticError::InvalidFeatures)
				} else if !features.supports_payment_secret() {
					Err(SemanticError::InvalidFeatures)
				} else {
					Ok(())
				}
			},
			Some(_) => unreachable!(),
		}
	}

	/// Check that the invoice is signed correctly and that key recovery works
	pub fn check_signature(&self) -> Result<(), SemanticError> {
		match self.signed_invoice.recover_payee_pub_key() {
			Err(secp256k1::Error::InvalidRecoveryId) =>
				return Err(SemanticError::InvalidRecoveryId),
			Err(secp256k1::Error::InvalidSignature) =>
				return Err(SemanticError::InvalidSignature),
			Err(e) => panic!("no other error may occur, got {:?}", e),
			Ok(_) => {},
		}

		if !self.signed_invoice.check_signature() {
			return Err(SemanticError::InvalidSignature);
		}

		Ok(())
	}

	/// Constructs an `Invoice` from a `SignedRawInvoice` by checking all its invariants.
	/// ```
	/// use lightning_invoice::*;
	///
	/// let invoice = "lnbc100p1psj9jhxdqud3jxktt5w46x7unfv9kz6mn0v3jsnp4q0d3p2sfluzdx45tqcs\
	/// h2pu5qc7lgq0xs578ngs6s0s68ua4h7cvspp5q6rmq35js88zp5dvwrv9m459tnk2zunwj5jalqtyxqulh0l\
	/// 5gflssp5nf55ny5gcrfl30xuhzj3nphgj27rstekmr9fw3ny5989s300gyus9qyysgqcqpcrzjqw2sxwe993\
	/// h5pcm4dxzpvttgza8zhkqxpgffcrf5v25nwpr3cmfg7z54kuqq8rgqqqqqqqq2qqqqq9qq9qrzjqd0ylaqcl\
	/// j9424x9m8h2vcukcgnm6s56xfgu3j78zyqzhgs4hlpzvznlugqq9vsqqqqqqqlgqqqqqeqq9qrzjqwldmj9d\
	/// ha74df76zhx6l9we0vjdquygcdt3kssupehe64g6yyp5yz5rhuqqwccqqyqqqqlgqqqqjcqq9qrzjqf9e58a\
	/// guqr0rcun0ajlvmzq3ek63cw2w282gv3z5uupmuwvgjtq2z55qsqqg6qqqyqqqrtnqqqzq3cqygrzjqvphms\
	/// ywntrrhqjcraumvc4y6r8v4z5v593trte429v4hredj7ms5z52usqq9ngqqqqqqqlgqqqqqqgq9qrzjq2v0v\
	/// p62g49p7569ev48cmulecsxe59lvaw3wlxm7r982zxa9zzj7z5l0cqqxusqqyqqqqlgqqqqqzsqygarl9fh3\
	/// 8s0gyuxjjgux34w75dnc6xp2l35j7es3jd4ugt3lu0xzre26yg5m7ke54n2d5sym4xcmxtl8238xxvw5h5h5\
	/// j5r6drg6k6zcqj0fcwg";
	///
	/// let signed = invoice.parse::<SignedRawInvoice>().unwrap();
	///
	/// assert!(Invoice::from_signed(signed).is_ok());
	/// ```
	pub fn from_signed(signed_invoice: SignedRawInvoice) -> Result<Self, SemanticError> {
		let invoice = Invoice {
			signed_invoice: signed_invoice,
		};
		invoice.check_field_counts()?;
		invoice.check_feature_bits()?;
		invoice.check_signature()?;
		invoice.check_amount()?;

		Ok(invoice)
	}

	/// Returns the `Invoice`'s timestamp (should equal its creation time)
	#[cfg(feature = "std")]
	pub fn timestamp(&self) -> SystemTime {
		self.signed_invoice.raw_invoice().data.timestamp.as_time()
	}

	/// Returns the `Invoice`'s timestamp as a duration since the Unix epoch
	pub fn duration_since_epoch(&self) -> Duration {
		self.signed_invoice.raw_invoice().data.timestamp.0
	}

	/// Returns an iterator over all tagged fields of this Invoice.
	///
	/// (C-not exported) As there is not yet a manual mapping for a FilterMap
	pub fn tagged_fields(&self)
		-> FilterMap<Iter<RawTaggedField>, fn(&RawTaggedField) -> Option<&TaggedField>> {
		self.signed_invoice.raw_invoice().known_tagged_fields()
	}

	/// Returns the hash to which we will receive the preimage on completion of the payment
	pub fn payment_hash(&self) -> &sha256::Hash {
		&self.signed_invoice.payment_hash().expect("checked by constructor").0
	}

	/// Return the description or a hash of it for longer ones
	///
	/// (C-not exported) because we don't yet export InvoiceDescription
	pub fn description(&self) -> InvoiceDescription {
		if let Some(ref direct) = self.signed_invoice.description() {
			return InvoiceDescription::Direct(direct);
		} else if let Some(ref hash) = self.signed_invoice.description_hash() {
			return InvoiceDescription::Hash(hash);
		}
		unreachable!("ensured by constructor");
	}

	/// Get the payee's public key if one was included in the invoice
	pub fn payee_pub_key(&self) -> Option<&PublicKey> {
		self.signed_invoice.payee_pub_key().map(|x| &x.0)
	}

	/// Get the payment secret if one was included in the invoice
	pub fn payment_secret(&self) -> &PaymentSecret {
		self.signed_invoice.payment_secret().expect("was checked by constructor")
	}

	/// Get the invoice features if they were included in the invoice
	pub fn features(&self) -> Option<&InvoiceFeatures> {
		self.signed_invoice.features()
	}

	/// Recover the payee's public key (only to be used if none was included in the invoice)
	pub fn recover_payee_pub_key(&self) -> PublicKey {
		self.signed_invoice.recover_payee_pub_key().expect("was checked by constructor").0
	}

	/// Returns the invoice's expiry time, if present, otherwise [`DEFAULT_EXPIRY_TIME`].
	pub fn expiry_time(&self) -> Duration {
		self.signed_invoice.expiry_time()
			.map(|x| x.0)
			.unwrap_or(Duration::from_secs(DEFAULT_EXPIRY_TIME))
	}

	/// Returns whether the invoice has expired.
	#[cfg(feature = "std")]
	pub fn is_expired(&self) -> bool {
		Self::is_expired_from_epoch(&self.timestamp(), self.expiry_time())
	}

	/// Returns whether the expiry time from the given epoch has passed.
	#[cfg(feature = "std")]
	pub(crate) fn is_expired_from_epoch(epoch: &SystemTime, expiry_time: Duration) -> bool {
		match epoch.elapsed() {
			Ok(elapsed) => elapsed > expiry_time,
			Err(_) => false,
		}
	}

	/// Returns whether the expiry time would pass at the given point in time.
	/// `at_time` is the timestamp as a duration since the Unix epoch.
	pub fn would_expire(&self, at_time: Duration) -> bool {
		self.duration_since_epoch()
			.checked_add(self.expiry_time())
			.unwrap_or_else(|| Duration::new(u64::max_value(), 1_000_000_000 - 1)) < at_time
	}

	/// Returns the invoice's `min_final_cltv_expiry` time, if present, otherwise
	/// [`DEFAULT_MIN_FINAL_CLTV_EXPIRY`].
	pub fn min_final_cltv_expiry(&self) -> u64 {
		self.signed_invoice.min_final_cltv_expiry()
			.map(|x| x.0)
			.unwrap_or(DEFAULT_MIN_FINAL_CLTV_EXPIRY)
	}

	/// Returns a list of all fallback addresses
	///
	/// (C-not exported) as we don't support Vec<&NonOpaqueType>
	pub fn fallbacks(&self) -> Vec<&Fallback> {
		self.signed_invoice.fallbacks()
	}

	/// Returns a list of all routes included in the invoice
	pub fn private_routes(&self) -> Vec<&PrivateRoute> {
		self.signed_invoice.private_routes()
	}

	/// Returns a list of all routes included in the invoice as the underlying hints
	pub fn route_hints(&self) -> Vec<RouteHint> {
		find_all_extract!(
			self.signed_invoice.known_tagged_fields(), TaggedField::PrivateRoute(ref x), x
		).map(|route| (**route).clone()).collect()
	}

	/// Returns the currency for which the invoice was issued
	pub fn currency(&self) -> Currency {
		self.signed_invoice.currency()
	}

	/// Returns the amount if specified in the invoice as millisatoshis.
	pub fn amount_milli_satoshis(&self) -> Option<u64> {
		self.signed_invoice.amount_pico_btc().map(|v| v / 10)
	}

	/// Returns the amount if specified in the invoice as pico <currency>.
	fn amount_pico_btc(&self) -> Option<u64> {
		self.signed_invoice.amount_pico_btc()
	}
}

impl From<TaggedField> for RawTaggedField {
	fn from(tf: TaggedField) -> Self {
		RawTaggedField::KnownSemantics(tf)
	}
}

impl TaggedField {
	/// Numeric representation of the field's tag
	pub fn tag(&self) -> u5 {
		let tag = match *self {
			TaggedField::PaymentHash(_) => constants::TAG_PAYMENT_HASH,
			TaggedField::Description(_) => constants::TAG_DESCRIPTION,
			TaggedField::PayeePubKey(_) => constants::TAG_PAYEE_PUB_KEY,
			TaggedField::DescriptionHash(_) => constants::TAG_DESCRIPTION_HASH,
			TaggedField::ExpiryTime(_) => constants::TAG_EXPIRY_TIME,
			TaggedField::MinFinalCltvExpiry(_) => constants::TAG_MIN_FINAL_CLTV_EXPIRY,
			TaggedField::Fallback(_) => constants::TAG_FALLBACK,
			TaggedField::PrivateRoute(_) => constants::TAG_PRIVATE_ROUTE,
			TaggedField::PaymentSecret(_) => constants::TAG_PAYMENT_SECRET,
			TaggedField::Features(_) => constants::TAG_FEATURES,
		};

		u5::try_from_u8(tag).expect("all tags defined are <32")
	}
}

impl Description {

	/// Creates a new `Description` if `description` is at most 1023 __bytes__ long,
	/// returns `CreationError::DescriptionTooLong` otherwise
	///
	/// Please note that single characters may use more than one byte due to UTF8 encoding.
	pub fn new(description: String) -> Result<Description, CreationError> {
		if description.len() > 639 {
			Err(CreationError::DescriptionTooLong)
		} else {
			Ok(Description(description))
		}
	}

	/// Returns the underlying description `String`
	pub fn into_inner(self) -> String {
		self.0
	}
}

impl Into<String> for Description {
	fn into(self) -> String {
		self.into_inner()
	}
}

impl Deref for Description {
	type Target = str;

	fn deref(&self) -> &str {
		&self.0
	}
}

impl From<PublicKey> for PayeePubKey {
	fn from(pk: PublicKey) -> Self {
		PayeePubKey(pk)
	}
}

impl Deref for PayeePubKey {
	type Target = PublicKey;

	fn deref(&self) -> &PublicKey {
		&self.0
	}
}

impl ExpiryTime {
	/// Construct an `ExpiryTime` from seconds.
	pub fn from_seconds(seconds: u64) -> ExpiryTime {
		ExpiryTime(Duration::from_secs(seconds))
	}

	/// Construct an `ExpiryTime` from a `Duration`.
	pub fn from_duration(duration: Duration) -> ExpiryTime {
		ExpiryTime(duration)
	}

	/// Returns the expiry time in seconds
	pub fn as_seconds(&self) -> u64 {
		self.0.as_secs()
	}

	/// Returns a reference to the underlying `Duration` (=expiry time)
	pub fn as_duration(&self) -> &Duration {
		&self.0
	}
}

impl PrivateRoute {
	/// Creates a new (partial) route from a list of hops
	pub fn new(hops: RouteHint) -> Result<PrivateRoute, CreationError> {
		if hops.0.len() <= 12 {
			Ok(PrivateRoute(hops))
		} else {
			Err(CreationError::RouteTooLong)
		}
	}

	/// Returns the underlying list of hops
	pub fn into_inner(self) -> RouteHint {
		self.0
	}
}

impl Into<RouteHint> for PrivateRoute {
	fn into(self) -> RouteHint {
		self.into_inner()
	}
}

impl Deref for PrivateRoute {
	type Target = RouteHint;

	fn deref(&self) -> &RouteHint {
		&self.0
	}
}

impl Deref for InvoiceSignature {
	type Target = RecoverableSignature;

	fn deref(&self) -> &RecoverableSignature {
		&self.0
	}
}

impl Deref for SignedRawInvoice {
	type Target = RawInvoice;

	fn deref(&self) -> &RawInvoice {
		&self.raw_invoice
	}
}

/// Errors that may occur when constructing a new `RawInvoice` or `Invoice`
#[derive(Eq, PartialEq, Debug, Clone)]
pub enum CreationError {
	/// The supplied description string was longer than 639 __bytes__ (see [`Description::new(…)`](./struct.Description.html#method.new))
	DescriptionTooLong,

	/// The specified route has too many hops and can't be encoded
	RouteTooLong,

	/// The Unix timestamp of the supplied date is less than zero or greater than 35-bits
	TimestampOutOfBounds,

	/// The supplied millisatoshi amount was greater than the total bitcoin supply.
	InvalidAmount,

	/// Route hints were required for this invoice and were missing. Applies to
	/// [phantom invoices].
	///
	/// [phantom invoices]: crate::utils::create_phantom_invoice
	MissingRouteHints,
}

impl Display for CreationError {
	fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
		match self {
			CreationError::DescriptionTooLong => f.write_str("The supplied description string was longer than 639 bytes"),
			CreationError::RouteTooLong => f.write_str("The specified route has too many hops and can't be encoded"),
			CreationError::TimestampOutOfBounds => f.write_str("The Unix timestamp of the supplied date is less than zero or greater than 35-bits"),
			CreationError::InvalidAmount => f.write_str("The supplied millisatoshi amount was greater than the total bitcoin supply"),
			CreationError::MissingRouteHints => f.write_str("The invoice required route hints and they weren't provided"),
		}
	}
}

#[cfg(feature = "std")]
impl std::error::Error for CreationError { }

/// Errors that may occur when converting a `RawInvoice` to an `Invoice`. They relate to the
/// requirements sections in BOLT #11
#[derive(Eq, PartialEq, Debug, Clone)]
pub enum SemanticError {
	/// The invoice is missing the mandatory payment hash
	NoPaymentHash,

	/// The invoice has multiple payment hashes which isn't allowed
	MultiplePaymentHashes,

	/// No description or description hash are part of the invoice
	NoDescription,

	/// The invoice contains multiple descriptions and/or description hashes which isn't allowed
	MultipleDescriptions,

	/// The invoice is missing the mandatory payment secret, which all modern lightning nodes
	/// should provide.
	NoPaymentSecret,

	/// The invoice contains multiple payment secrets
	MultiplePaymentSecrets,

	/// The invoice's features are invalid
	InvalidFeatures,

	/// The recovery id doesn't fit the signature/pub key
	InvalidRecoveryId,

	/// The invoice's signature is invalid
	InvalidSignature,

	/// The invoice's amount was not a whole number of millisatoshis
	ImpreciseAmount,
}

impl Display for SemanticError {
	fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
		match self {
			SemanticError::NoPaymentHash => f.write_str("The invoice is missing the mandatory payment hash"),
			SemanticError::MultiplePaymentHashes => f.write_str("The invoice has multiple payment hashes which isn't allowed"),
			SemanticError::NoDescription => f.write_str("No description or description hash are part of the invoice"),
			SemanticError::MultipleDescriptions => f.write_str("The invoice contains multiple descriptions and/or description hashes which isn't allowed"),
			SemanticError::NoPaymentSecret => f.write_str("The invoice is missing the mandatory payment secret"),
			SemanticError::MultiplePaymentSecrets => f.write_str("The invoice contains multiple payment secrets"),
			SemanticError::InvalidFeatures => f.write_str("The invoice's features are invalid"),
			SemanticError::InvalidRecoveryId => f.write_str("The recovery id doesn't fit the signature/pub key"),
			SemanticError::InvalidSignature => f.write_str("The invoice's signature is invalid"),
			SemanticError::ImpreciseAmount => f.write_str("The invoice's amount was not a whole number of millisatoshis"),
		}
	}
}

#[cfg(feature = "std")]
impl std::error::Error for SemanticError { }

/// When signing using a fallible method either an user-supplied `SignError` or a `CreationError`
/// may occur.
#[derive(Eq, PartialEq, Debug, Clone)]
pub enum SignOrCreationError<S = ()> {
	/// An error occurred during signing
	SignError(S),

	/// An error occurred while building the transaction
	CreationError(CreationError),
}

impl<S> Display for SignOrCreationError<S> {
	fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
		match self {
			SignOrCreationError::SignError(_) => f.write_str("An error occurred during signing"),
			SignOrCreationError::CreationError(err) => err.fmt(f),
		}
	}
}

#[cfg(feature = "serde")]
impl Serialize for Invoice {
	fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error> where S: Serializer {
		serializer.serialize_str(self.to_string().as_str())
	}
}
#[cfg(feature = "serde")]
impl<'de> Deserialize<'de> for Invoice {
	fn deserialize<D>(deserializer: D) -> Result<Invoice, D::Error> where D: Deserializer<'de> {
		let bolt11 = String::deserialize(deserializer)?
			.parse::<Invoice>()
			.map_err(|e| D::Error::custom(format!("{:?}", e)))?;

		Ok(bolt11)
	}
}

#[cfg(test)]
mod test {
	use bitcoin_hashes::hex::FromHex;
	use bitcoin_hashes::sha256;

	#[test]
	fn test_system_time_bounds_assumptions() {
		assert_eq!(
			::PositiveTimestamp::from_unix_timestamp(::MAX_TIMESTAMP + 1),
			Err(::CreationError::TimestampOutOfBounds)
		);
	}

	#[test]
	fn test_calc_invoice_hash() {
		use ::{RawInvoice, RawHrp, RawDataPart, Currency, PositiveTimestamp};
		use ::TaggedField::*;

		let invoice = RawInvoice {
			hrp: RawHrp {
				currency: Currency::Bitcoin,
				raw_amount: None,
				si_prefix: None,
			},
			data: RawDataPart {
				timestamp: PositiveTimestamp::from_unix_timestamp(1496314658).unwrap(),
				tagged_fields: vec![
					PaymentHash(::Sha256(sha256::Hash::from_hex(
						"0001020304050607080900010203040506070809000102030405060708090102"
					).unwrap())).into(),
					Description(::Description::new(
						"Please consider supporting this project".to_owned()
					).unwrap()).into(),
				],
			},
		};

		let expected_hash = [
			0xc3, 0xd4, 0xe8, 0x3f, 0x64, 0x6f, 0xa7, 0x9a, 0x39, 0x3d, 0x75, 0x27, 0x7b, 0x1d,
			0x85, 0x8d, 0xb1, 0xd1, 0xf7, 0xab, 0x71, 0x37, 0xdc, 0xb7, 0x83, 0x5d, 0xb2, 0xec,
			0xd5, 0x18, 0xe1, 0xc9
		];

		assert_eq!(invoice.hash(), expected_hash)
	}

	#[test]
	fn test_check_signature() {
		use TaggedField::*;
		use secp256k1::Secp256k1;
		use secp256k1::ecdsa::{RecoveryId, RecoverableSignature};
		use secp256k1::{SecretKey, PublicKey};
		use {SignedRawInvoice, InvoiceSignature, RawInvoice, RawHrp, RawDataPart, Currency, Sha256,
			 PositiveTimestamp};

		let invoice = SignedRawInvoice {
			raw_invoice: RawInvoice {
				hrp: RawHrp {
					currency: Currency::Bitcoin,
					raw_amount: None,
					si_prefix: None,
				},
				data: RawDataPart {
					timestamp: PositiveTimestamp::from_unix_timestamp(1496314658).unwrap(),
					tagged_fields: vec ! [
						PaymentHash(Sha256(sha256::Hash::from_hex(
							"0001020304050607080900010203040506070809000102030405060708090102"
						).unwrap())).into(),
						Description(
							::Description::new(
								"Please consider supporting this project".to_owned()
							).unwrap()
						).into(),
					],
				},
			},
			hash: [
				0xc3, 0xd4, 0xe8, 0x3f, 0x64, 0x6f, 0xa7, 0x9a, 0x39, 0x3d, 0x75, 0x27,
				0x7b, 0x1d, 0x85, 0x8d, 0xb1, 0xd1, 0xf7, 0xab, 0x71, 0x37, 0xdc, 0xb7,
				0x83, 0x5d, 0xb2, 0xec, 0xd5, 0x18, 0xe1, 0xc9
			],
			signature: InvoiceSignature(RecoverableSignature::from_compact(
				& [
					0x38u8, 0xec, 0x68, 0x91, 0x34, 0x5e, 0x20, 0x41, 0x45, 0xbe, 0x8a,
					0x3a, 0x99, 0xde, 0x38, 0xe9, 0x8a, 0x39, 0xd6, 0xa5, 0x69, 0x43,
					0x4e, 0x18, 0x45, 0xc8, 0xaf, 0x72, 0x05, 0xaf, 0xcf, 0xcc, 0x7f,
					0x42, 0x5f, 0xcd, 0x14, 0x63, 0xe9, 0x3c, 0x32, 0x88, 0x1e, 0xad,
					0x0d, 0x6e, 0x35, 0x6d, 0x46, 0x7e, 0xc8, 0xc0, 0x25, 0x53, 0xf9,
					0xaa, 0xb1, 0x5e, 0x57, 0x38, 0xb1, 0x1f, 0x12, 0x7f
				],
				RecoveryId::from_i32(0).unwrap()
			).unwrap()),
		};

		assert!(invoice.check_signature());

		let private_key = SecretKey::from_slice(
			&[
				0xe1, 0x26, 0xf6, 0x8f, 0x7e, 0xaf, 0xcc, 0x8b, 0x74, 0xf5, 0x4d, 0x26, 0x9f, 0xe2,
				0x06, 0xbe, 0x71, 0x50, 0x00, 0xf9, 0x4d, 0xac, 0x06, 0x7d, 0x1c, 0x04, 0xa8, 0xca,
				0x3b, 0x2d, 0xb7, 0x34
			][..]
		).unwrap();
		let public_key = PublicKey::from_secret_key(&Secp256k1::new(), &private_key);

		assert_eq!(invoice.recover_payee_pub_key(), Ok(::PayeePubKey(public_key)));

		let (raw_invoice, _, _) = invoice.into_parts();
		let new_signed = raw_invoice.sign::<_, ()>(|hash| {
			Ok(Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key))
		}).unwrap();

		assert!(new_signed.check_signature());
	}

	#[test]
	fn test_check_feature_bits() {
		use TaggedField::*;
		use lightning::ln::features::InvoiceFeatures;
		use secp256k1::Secp256k1;
		use secp256k1::SecretKey;
		use {RawInvoice, RawHrp, RawDataPart, Currency, Sha256, PositiveTimestamp, Invoice,
			 SemanticError};

		let private_key = SecretKey::from_slice(&[42; 32]).unwrap();
		let payment_secret = lightning::ln::PaymentSecret([21; 32]);
		let invoice_template = RawInvoice {
			hrp: RawHrp {
				currency: Currency::Bitcoin,
				raw_amount: None,
				si_prefix: None,
			},
			data: RawDataPart {
				timestamp: PositiveTimestamp::from_unix_timestamp(1496314658).unwrap(),
				tagged_fields: vec ! [
					PaymentHash(Sha256(sha256::Hash::from_hex(
						"0001020304050607080900010203040506070809000102030405060708090102"
					).unwrap())).into(),
					Description(
						::Description::new(
							"Please consider supporting this project".to_owned()
						).unwrap()
					).into(),
				],
			},
		};

		// Missing features
		let invoice = {
			let mut invoice = invoice_template.clone();
			invoice.data.tagged_fields.push(PaymentSecret(payment_secret).into());
			invoice.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key)))
		}.unwrap();
		assert_eq!(Invoice::from_signed(invoice), Err(SemanticError::InvalidFeatures));

		// Missing feature bits
		let invoice = {
			let mut invoice = invoice_template.clone();
			invoice.data.tagged_fields.push(PaymentSecret(payment_secret).into());
			invoice.data.tagged_fields.push(Features(InvoiceFeatures::empty()).into());
			invoice.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key)))
		}.unwrap();
		assert_eq!(Invoice::from_signed(invoice), Err(SemanticError::InvalidFeatures));

		// Including payment secret and feature bits
		let invoice = {
			let mut invoice = invoice_template.clone();
			invoice.data.tagged_fields.push(PaymentSecret(payment_secret).into());
			invoice.data.tagged_fields.push(Features(InvoiceFeatures::known()).into());
			invoice.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key)))
		}.unwrap();
		assert!(Invoice::from_signed(invoice).is_ok());

		// No payment secret or features
		let invoice = {
			let invoice = invoice_template.clone();
			invoice.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key)))
		}.unwrap();
		assert_eq!(Invoice::from_signed(invoice), Err(SemanticError::NoPaymentSecret));

		// No payment secret or feature bits
		let invoice = {
			let mut invoice = invoice_template.clone();
			invoice.data.tagged_fields.push(Features(InvoiceFeatures::empty()).into());
			invoice.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key)))
		}.unwrap();
		assert_eq!(Invoice::from_signed(invoice), Err(SemanticError::NoPaymentSecret));

		// Missing payment secret
		let invoice = {
			let mut invoice = invoice_template.clone();
			invoice.data.tagged_fields.push(Features(InvoiceFeatures::known()).into());
			invoice.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key)))
		}.unwrap();
		assert_eq!(Invoice::from_signed(invoice), Err(SemanticError::NoPaymentSecret));

		// Multiple payment secrets
		let invoice = {
			let mut invoice = invoice_template.clone();
			invoice.data.tagged_fields.push(PaymentSecret(payment_secret).into());
			invoice.data.tagged_fields.push(PaymentSecret(payment_secret).into());
			invoice.sign::<_, ()>(|hash| Ok(Secp256k1::new().sign_ecdsa_recoverable(hash, &private_key)))
		}.unwrap();
		assert_eq!(Invoice::from_signed(invoice), Err(SemanticError::MultiplePaymentSecrets));
	}

	#[test]
	fn test_builder_amount() {
		use ::*;

		let builder = InvoiceBuilder::new(Currency::Bitcoin)
			.description("Test".into())
			.payment_hash(sha256::Hash::from_slice(&[0;32][..]).unwrap())
			.duration_since_epoch(Duration::from_secs(1234567));

		let invoice = builder.clone()
			.amount_milli_satoshis(1500)
			.build_raw()
			.unwrap();

		assert_eq!(invoice.hrp.si_prefix, Some(SiPrefix::Nano));
		assert_eq!(invoice.hrp.raw_amount, Some(15));


		let invoice = builder.clone()
			.amount_milli_satoshis(150)
			.build_raw()
			.unwrap();

		assert_eq!(invoice.hrp.si_prefix, Some(SiPrefix::Pico));
		assert_eq!(invoice.hrp.raw_amount, Some(1500));
	}

	#[test]
	fn test_builder_fail() {
		use ::*;
		use lightning::routing::router::RouteHintHop;
		use std::iter::FromIterator;
		use secp256k1::PublicKey;

		let builder = InvoiceBuilder::new(Currency::Bitcoin)
			.payment_hash(sha256::Hash::from_slice(&[0;32][..]).unwrap())
			.duration_since_epoch(Duration::from_secs(1234567))
			.min_final_cltv_expiry(144);

		let too_long_string = String::from_iter(
			(0..1024).map(|_| '?')
		);

		let long_desc_res = builder.clone()
			.description(too_long_string)
			.build_raw();
		assert_eq!(long_desc_res, Err(CreationError::DescriptionTooLong));

		let route_hop = RouteHintHop {
			src_node_id: PublicKey::from_slice(
					&[
						0x03, 0x9e, 0x03, 0xa9, 0x01, 0xb8, 0x55, 0x34, 0xff, 0x1e, 0x92, 0xc4,
						0x3c, 0x74, 0x43, 0x1f, 0x7c, 0xe7, 0x20, 0x46, 0x06, 0x0f, 0xcf, 0x7a,
						0x95, 0xc3, 0x7e, 0x14, 0x8f, 0x78, 0xc7, 0x72, 0x55
					][..]
				).unwrap(),
			short_channel_id: 0,
			fees: RoutingFees {
				base_msat: 0,
				proportional_millionths: 0,
			},
			cltv_expiry_delta: 0,
			htlc_minimum_msat: None,
			htlc_maximum_msat: None,
		};
		let too_long_route = RouteHint(vec![route_hop; 13]);
		let long_route_res = builder.clone()
			.description("Test".into())
			.private_route(too_long_route)
			.build_raw();
		assert_eq!(long_route_res, Err(CreationError::RouteTooLong));

		let sign_error_res = builder.clone()
			.description("Test".into())
			.payment_secret(PaymentSecret([0; 32]))
			.try_build_signed(|_| {
				Err("ImaginaryError")
			});
		assert_eq!(sign_error_res, Err(SignOrCreationError::SignError("ImaginaryError")));
	}

	#[test]
	fn test_builder_ok() {
		use ::*;
		use lightning::routing::router::RouteHintHop;
		use secp256k1::Secp256k1;
		use secp256k1::{SecretKey, PublicKey};
		use std::time::{UNIX_EPOCH, Duration};

		let secp_ctx = Secp256k1::new();

		let private_key = SecretKey::from_slice(
			&[
				0xe1, 0x26, 0xf6, 0x8f, 0x7e, 0xaf, 0xcc, 0x8b, 0x74, 0xf5, 0x4d, 0x26, 0x9f, 0xe2,
				0x06, 0xbe, 0x71, 0x50, 0x00, 0xf9, 0x4d, 0xac, 0x06, 0x7d, 0x1c, 0x04, 0xa8, 0xca,
				0x3b, 0x2d, 0xb7, 0x34
			][..]
		).unwrap();
		let public_key = PublicKey::from_secret_key(&secp_ctx, &private_key);

		let route_1 = RouteHint(vec![
			RouteHintHop {
				src_node_id: public_key.clone(),
				short_channel_id: de::parse_int_be(&[123; 8], 256).expect("short chan ID slice too big?"),
				fees: RoutingFees {
					base_msat: 2,
					proportional_millionths: 1,
				},
				cltv_expiry_delta: 145,
				htlc_minimum_msat: None,
				htlc_maximum_msat: None,
			},
			RouteHintHop {
				src_node_id: public_key.clone(),
				short_channel_id: de::parse_int_be(&[42; 8], 256).expect("short chan ID slice too big?"),
				fees: RoutingFees {
					base_msat: 3,
					proportional_millionths: 2,
				},
				cltv_expiry_delta: 146,
				htlc_minimum_msat: None,
				htlc_maximum_msat: None,
			}
		]);

		let route_2 = RouteHint(vec![
			RouteHintHop {
				src_node_id: public_key.clone(),
				short_channel_id: 0,
				fees: RoutingFees {
					base_msat: 4,
					proportional_millionths: 3,
				},
				cltv_expiry_delta: 147,
				htlc_minimum_msat: None,
				htlc_maximum_msat: None,
			},
			RouteHintHop {
				src_node_id: public_key.clone(),
				short_channel_id: de::parse_int_be(&[1; 8], 256).expect("short chan ID slice too big?"),
				fees: RoutingFees {
					base_msat: 5,
					proportional_millionths: 4,
				},
				cltv_expiry_delta: 148,
				htlc_minimum_msat: None,
				htlc_maximum_msat: None,
			}
		]);

		let builder = InvoiceBuilder::new(Currency::BitcoinTestnet)
			.amount_milli_satoshis(123)
			.duration_since_epoch(Duration::from_secs(1234567))
			.payee_pub_key(public_key.clone())
			.expiry_time(Duration::from_secs(54321))
			.min_final_cltv_expiry(144)
			.fallback(Fallback::PubKeyHash([0;20]))
			.private_route(route_1.clone())
			.private_route(route_2.clone())
			.description_hash(sha256::Hash::from_slice(&[3;32][..]).unwrap())
			.payment_hash(sha256::Hash::from_slice(&[21;32][..]).unwrap())
			.payment_secret(PaymentSecret([42; 32]))
			.basic_mpp();

		let invoice = builder.clone().build_signed(|hash| {
			secp_ctx.sign_ecdsa_recoverable(hash, &private_key)
		}).unwrap();

		assert!(invoice.check_signature().is_ok());
		assert_eq!(invoice.tagged_fields().count(), 10);

		assert_eq!(invoice.amount_milli_satoshis(), Some(123));
		assert_eq!(invoice.amount_pico_btc(), Some(1230));
		assert_eq!(invoice.currency(), Currency::BitcoinTestnet);
		#[cfg(feature = "std")]
		assert_eq!(
			invoice.timestamp().duration_since(UNIX_EPOCH).unwrap().as_secs(),
			1234567
		);
		assert_eq!(invoice.payee_pub_key(), Some(&public_key));
		assert_eq!(invoice.expiry_time(), Duration::from_secs(54321));
		assert_eq!(invoice.min_final_cltv_expiry(), 144);
		assert_eq!(invoice.fallbacks(), vec![&Fallback::PubKeyHash([0;20])]);
		assert_eq!(invoice.private_routes(), vec![&PrivateRoute(route_1), &PrivateRoute(route_2)]);
		assert_eq!(
			invoice.description(),
			InvoiceDescription::Hash(&Sha256(sha256::Hash::from_slice(&[3;32][..]).unwrap()))
		);
		assert_eq!(invoice.payment_hash(), &sha256::Hash::from_slice(&[21;32][..]).unwrap());
		assert_eq!(invoice.payment_secret(), &PaymentSecret([42; 32]));
		assert_eq!(invoice.features(), Some(&InvoiceFeatures::known()));

		let raw_invoice = builder.build_raw().unwrap();
		assert_eq!(raw_invoice, *invoice.into_signed_raw().raw_invoice())
	}

	#[test]
	fn test_default_values() {
		use ::*;
		use secp256k1::Secp256k1;
		use secp256k1::SecretKey;

		let signed_invoice = InvoiceBuilder::new(Currency::Bitcoin)
			.description("Test".into())
			.payment_hash(sha256::Hash::from_slice(&[0;32][..]).unwrap())
			.payment_secret(PaymentSecret([0; 32]))
			.duration_since_epoch(Duration::from_secs(1234567))
			.build_raw()
			.unwrap()
			.sign::<_, ()>(|hash| {
				let privkey = SecretKey::from_slice(&[41; 32]).unwrap();
				let secp_ctx = Secp256k1::new();
				Ok(secp_ctx.sign_ecdsa_recoverable(hash, &privkey))
			})
			.unwrap();
		let invoice = Invoice::from_signed(signed_invoice).unwrap();

		assert_eq!(invoice.min_final_cltv_expiry(), DEFAULT_MIN_FINAL_CLTV_EXPIRY);
		assert_eq!(invoice.expiry_time(), Duration::from_secs(DEFAULT_EXPIRY_TIME));
		assert!(!invoice.would_expire(Duration::from_secs(1234568)));
	}

	#[test]
	fn test_expiration() {
		use ::*;
		use secp256k1::Secp256k1;
		use secp256k1::SecretKey;

		let signed_invoice = InvoiceBuilder::new(Currency::Bitcoin)
			.description("Test".into())
			.payment_hash(sha256::Hash::from_slice(&[0;32][..]).unwrap())
			.payment_secret(PaymentSecret([0; 32]))
			.duration_since_epoch(Duration::from_secs(1234567))
			.build_raw()
			.unwrap()
			.sign::<_, ()>(|hash| {
				let privkey = SecretKey::from_slice(&[41; 32]).unwrap();
				let secp_ctx = Secp256k1::new();
				Ok(secp_ctx.sign_ecdsa_recoverable(hash, &privkey))
			})
			.unwrap();
		let invoice = Invoice::from_signed(signed_invoice).unwrap();

		assert!(invoice.would_expire(Duration::from_secs(1234567 + DEFAULT_EXPIRY_TIME + 1)));
	}

	#[cfg(feature = "serde")]
	#[test]
	fn test_serde() {
		let invoice_str = "lnbc100p1psj9jhxdqud3jxktt5w46x7unfv9kz6mn0v3jsnp4q0d3p2sfluzdx45tqcs\
			h2pu5qc7lgq0xs578ngs6s0s68ua4h7cvspp5q6rmq35js88zp5dvwrv9m459tnk2zunwj5jalqtyxqulh0l\
			5gflssp5nf55ny5gcrfl30xuhzj3nphgj27rstekmr9fw3ny5989s300gyus9qyysgqcqpcrzjqw2sxwe993\
			h5pcm4dxzpvttgza8zhkqxpgffcrf5v25nwpr3cmfg7z54kuqq8rgqqqqqqqq2qqqqq9qq9qrzjqd0ylaqcl\
			j9424x9m8h2vcukcgnm6s56xfgu3j78zyqzhgs4hlpzvznlugqq9vsqqqqqqqlgqqqqqeqq9qrzjqwldmj9d\
			ha74df76zhx6l9we0vjdquygcdt3kssupehe64g6yyp5yz5rhuqqwccqqyqqqqlgqqqqjcqq9qrzjqf9e58a\
			guqr0rcun0ajlvmzq3ek63cw2w282gv3z5uupmuwvgjtq2z55qsqqg6qqqyqqqrtnqqqzq3cqygrzjqvphms\
			ywntrrhqjcraumvc4y6r8v4z5v593trte429v4hredj7ms5z52usqq9ngqqqqqqqlgqqqqqqgq9qrzjq2v0v\
			p62g49p7569ev48cmulecsxe59lvaw3wlxm7r982zxa9zzj7z5l0cqqxusqqyqqqqlgqqqqqzsqygarl9fh3\
			8s0gyuxjjgux34w75dnc6xp2l35j7es3jd4ugt3lu0xzre26yg5m7ke54n2d5sym4xcmxtl8238xxvw5h5h5\
			j5r6drg6k6zcqj0fcwg";
		let invoice = invoice_str.parse::<super::Invoice>().unwrap();
		let serialized_invoice = serde_json::to_string(&invoice).unwrap();
		let deserialized_invoice: super::Invoice = serde_json::from_str(serialized_invoice.as_str()).unwrap();
		assert_eq!(invoice, deserialized_invoice);
		assert_eq!(invoice_str, deserialized_invoice.to_string().as_str());
		assert_eq!(invoice_str, serialized_invoice.as_str().trim_matches('\"'));
	}
}