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

use core::fmt::{Display, Error as FmtError, Formatter};

use super::error::TokenTransferError;
use crate::core::ics04_channel::msgs::acknowledgement::Acknowledgement;
use crate::prelude::*;

/// A string constant included in error acknowledgements.
/// NOTE: Changing this const is state machine breaking as acknowledgements are written into state
pub const ACK_ERR_STR: &str = "error handling packet on destination chain: see events for details";

/// A successful acknowledgement, equivalent to `base64::encode(0x01)`.
pub const ACK_SUCCESS_B64: &str = "AQ==";

#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum ConstAckSuccess {
    #[cfg_attr(feature = "serde", serde(rename = "AQ=="))]
    Success,
}

#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[derive(Clone, Debug, PartialEq, Eq)]
pub enum TokenTransferAcknowledgement {
    /// Successful Acknowledgement
    /// e.g. `{"result":"AQ=="}`
    #[cfg_attr(feature = "serde", serde(rename = "result"))]
    Success(ConstAckSuccess),
    /// Error Acknowledgement
    /// e.g. `{"error":"cannot unmarshal ICS-20 transfer packet data"}`
    #[cfg_attr(feature = "serde", serde(rename = "error"))]
    Error(String),
}

impl TokenTransferAcknowledgement {
    pub fn success() -> Self {
        Self::Success(ConstAckSuccess::Success)
    }

    pub fn from_error(err: TokenTransferError) -> Self {
        Self::Error(format!("{ACK_ERR_STR}: {err}"))
    }

    pub fn is_successful(&self) -> bool {
        matches!(self, TokenTransferAcknowledgement::Success(_))
    }
}

impl Display for TokenTransferAcknowledgement {
    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), FmtError> {
        match self {
            TokenTransferAcknowledgement::Success(_) => write!(f, "{ACK_SUCCESS_B64}"),
            TokenTransferAcknowledgement::Error(err_str) => write!(f, "{err_str}"),
        }
    }
}

impl From<TokenTransferAcknowledgement> for Vec<u8> {
    fn from(ack: TokenTransferAcknowledgement) -> Self {
        // WARNING: Make sure all branches always return a non-empty vector.
        // Otherwise, the conversion to `Acknowledgement` will panic.
        match ack {
            TokenTransferAcknowledgement::Success(_) => r#"{"result":"AQ=="}"#.as_bytes().into(),
            TokenTransferAcknowledgement::Error(s) => alloc::format!(r#"{{"error":"{s}"}}"#).into(),
        }
    }
}

impl From<TokenTransferAcknowledgement> for Acknowledgement {
    fn from(ack: TokenTransferAcknowledgement) -> Self {
        let v: Vec<u8> = ack.into();

        v.try_into()
            .expect("token transfer internal error: ack is never supposed to be empty")
    }
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test_ack_ser() {
        fn ser_json_assert_eq(ack: TokenTransferAcknowledgement, json_str: &str) {
            let ser = serde_json::to_string(&ack).unwrap();
            assert_eq!(ser, json_str)
        }

        ser_json_assert_eq(
            TokenTransferAcknowledgement::success(),
            r#"{"result":"AQ=="}"#,
        );
        ser_json_assert_eq(
            TokenTransferAcknowledgement::Error(
                "cannot unmarshal ICS-20 transfer packet data".to_owned(),
            ),
            r#"{"error":"cannot unmarshal ICS-20 transfer packet data"}"#,
        );
    }

    #[test]
    fn test_ack_success_to_vec() {
        let ack_success: Vec<u8> = TokenTransferAcknowledgement::success().into();

        // Check that it's the same output as ibc-go
        // Note: this also implicitly checks that the ack bytes are non-empty,
        // which would make the conversion to `Acknowledgement` panic
        assert_eq!(ack_success, r#"{"result":"AQ=="}"#.as_bytes());
    }

    #[test]
    fn test_ack_error_to_vec() {
        let ack_error: Vec<u8> = TokenTransferAcknowledgement::Error(
            "cannot unmarshal ICS-20 transfer packet data".to_string(),
        )
        .into();

        // Check that it's the same output as ibc-go
        // Note: this also implicitly checks that the ack bytes are non-empty,
        // which would make the conversion to `Acknowledgement` panic
        assert_eq!(
            ack_error,
            r#"{"error":"cannot unmarshal ICS-20 transfer packet data"}"#.as_bytes()
        );
    }

    #[test]
    fn test_ack_de() {
        fn de_json_assert_eq(json_str: &str, ack: TokenTransferAcknowledgement) {
            let de = serde_json::from_str::<TokenTransferAcknowledgement>(json_str).unwrap();
            assert_eq!(de, ack)
        }

        de_json_assert_eq(
            r#"{"result":"AQ=="}"#,
            TokenTransferAcknowledgement::success(),
        );
        de_json_assert_eq(
            r#"{"error":"cannot unmarshal ICS-20 transfer packet data"}"#,
            TokenTransferAcknowledgement::Error(
                "cannot unmarshal ICS-20 transfer packet data".to_owned(),
            ),
        );

        assert!(
            serde_json::from_str::<TokenTransferAcknowledgement>(r#"{"result":"AQ="}"#).is_err()
        );
        assert!(
            serde_json::from_str::<TokenTransferAcknowledgement>(r#"{"success":"AQ=="}"#).is_err()
        );
    }
}