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

use crate::streamable_struct;
use crate::{bytes::Bytes32, BytesImpl};
use chik_streamable_macro::Streamable;
use klvm_traits::{
    destructure_list, klvm_list, match_list, FromKlvm, FromKlvmError, KlvmDecoder, KlvmEncoder,
    ToKlvm, ToKlvmError,
};
use sha2::{Digest, Sha256};
use std::convert::TryInto;

#[cfg(feature = "py-bindings")]
use pyo3::prelude::*;

streamable_struct!(Coin {
    parent_coin_info: Bytes32,
    puzzle_hash: Bytes32,
    amount: u64,
});

impl Coin {
    pub fn coin_id(&self) -> [u8; 32] {
        let mut hasher = Sha256::new();
        hasher.update(self.parent_coin_info);
        hasher.update(self.puzzle_hash);

        let amount_bytes = self.amount.to_be_bytes();
        if self.amount >= 0x8000000000000000_u64 {
            hasher.update([0_u8]);
            hasher.update(amount_bytes);
        } else {
            let start = match self.amount {
                n if n >= 0x80000000000000_u64 => 0,
                n if n >= 0x800000000000_u64 => 1,
                n if n >= 0x8000000000_u64 => 2,
                n if n >= 0x80000000_u64 => 3,
                n if n >= 0x800000_u64 => 4,
                n if n >= 0x8000_u64 => 5,
                n if n >= 0x80_u64 => 6,
                n if n > 0 => 7,
                _ => 8,
            };
            hasher.update(&amount_bytes[start..]);
        }

        hasher.finalize().as_slice().try_into().unwrap()
    }
}

#[cfg(feature = "py-bindings")]
#[pymethods]
impl Coin {
    fn name<'p>(&self, py: pyo3::Python<'p>) -> pyo3::PyResult<&'p pyo3::types::PyBytes> {
        Ok(pyo3::types::PyBytes::new(py, &self.coin_id()))
    }
}

impl<N> ToKlvm<N> for Coin {
    fn to_klvm(&self, encoder: &mut impl KlvmEncoder<Node = N>) -> Result<N, ToKlvmError> {
        klvm_list!(self.parent_coin_info, self.puzzle_hash, self.amount).to_klvm(encoder)
    }
}

impl<N> FromKlvm<N> for Coin {
    fn from_klvm(decoder: &impl KlvmDecoder<Node = N>, node: N) -> Result<Self, FromKlvmError> {
        let destructure_list!(parent_coin_info, puzzle_hash, amount) =
            <match_list!(BytesImpl<32>, BytesImpl<32>, u64)>::from_klvm(decoder, node)?;
        Ok(Coin {
            parent_coin_info,
            puzzle_hash,
            amount,
        })
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use klvmr::{
        serde::{node_from_bytes, node_to_bytes},
        Allocator,
    };
    use rstest::rstest;

    #[rstest]
    #[case(0, &[])]
    #[case(1, &[1])]
    #[case(0xff, &[0, 0xff])]
    #[case(0xffff, &[0, 0xff, 0xff])]
    #[case(0xffffff, &[0, 0xff, 0xff, 0xff])]
    #[case(0xffffffff, &[0, 0xff, 0xff, 0xff, 0xff])]
    #[case(0xffffffffff, &[0, 0xff, 0xff, 0xff, 0xff, 0xff])]
    #[case(0xffffffffffffffff, &[0, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff])]
    #[case(0x7f, &[0x7f])]
    #[case(0x7fff, &[0x7f, 0xff])]
    #[case(0x7fffff, &[0x7f, 0xff, 0xff])]
    #[case(0x7fffffff, &[0x7f, 0xff, 0xff, 0xff])]
    #[case(0x7fffffffff, &[0x7f, 0xff, 0xff, 0xff, 0xff])]
    #[case(0x7fffffffffffffff, &[0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff])]
    #[case(0x80, &[0, 0x80])]
    #[case(0x8000, &[0, 0x80, 0x00])]
    #[case(0x800000, &[0, 0x80, 0x00, 0x00])]
    #[case(0x80000000, &[0, 0x80, 0x00, 0x00, 0x00])]
    #[case(0x8000000000, &[0, 0x80, 0x00, 0x00, 0x00, 0x00])]
    #[case(0x8000000000000000, &[0, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00])]
    fn coin_id(#[case] amount: u64, #[case] bytes: &[u8]) {
        let parent_coin = b"---foo---                       ";
        let puzzle_hash = b"---bar---                       ";

        let c = Coin::new(parent_coin.into(), puzzle_hash.into(), amount);
        let mut sha256 = Sha256::new();
        sha256.update(parent_coin);
        sha256.update(puzzle_hash);
        sha256.update(bytes);
        assert_eq!(c.coin_id(), &sha256.finalize() as &[u8]);
    }

    #[test]
    fn coin_roundtrip() {
        let a = &mut Allocator::new();
        let expected = "ffa09e144397decd2b831551f9710c17ae776d9c5a3ae5283c5f9747263fd1255381ffa0eff07522495060c066f66f32acc2a77e3a3e737aca8baea4d1a64ea4cdc13da9ff0180";
        let expected_bytes = hex::decode(expected).unwrap();

        let ptr = node_from_bytes(a, &expected_bytes).unwrap();
        let coin = Coin::from_klvm(a, ptr).unwrap();

        let round_trip = coin.to_klvm(a).unwrap();
        assert_eq!(expected, hex::encode(node_to_bytes(a, round_trip).unwrap()));
    }
}