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

use bc_components::DigestProvider;

use crate::{Envelope, EnvelopeError, EnvelopeEncodable};

use super::envelope::EnvelopeCase;

/// Support for adding assertions.
impl Envelope {
    /// Returns the result of adding the given assertion to the envelope.
    pub fn add_assertion(&self, predicate: impl EnvelopeEncodable, object: impl EnvelopeEncodable) -> Self {
        let assertion = Self::new_assertion(predicate, object);
        self.add_optional_assertion_envelope(Some(assertion)).unwrap()
    }

    /// Returns the result of adding the given assertion to the envelope.
    ///
    /// The assertion envelope must be a valid assertion envelope, or an
    /// obscured variant (elided, encrypted, compressed) of one.
    pub fn add_assertion_envelope(&self, assertion_envelope: impl EnvelopeEncodable) -> Result<Self, EnvelopeError> {
        self.add_optional_assertion_envelope(Some(assertion_envelope.into()))
    }

    /// Returns the result of adding the given array of assertions to the envelope.
    ///
    /// Each assertion envelope must be a valid assertion envelope, or an
    /// obscured variant (elided, encrypted, compressed) of one.
    pub fn add_assertion_envelopes(&self, assertions: &[Self]) -> Result<Self, EnvelopeError> {
        let mut e = self.clone();
        for assertion in assertions {
            e = e.add_assertion_envelope(assertion.clone())?;
        }
        Ok(e)
    }

    /// If the optional assertion is present, returns the result of adding it to
    /// the envelope. Otherwise, returns the envelope unchanged.
    ///
    /// The assertion envelope must be a valid assertion envelope, or an
    /// obscured variant (elided, encrypted, compressed) of one.
    pub fn add_optional_assertion_envelope(&self, assertion: Option<Self>) -> Result<Self, EnvelopeError> {
        match assertion {
            Some(assertion) => {
                if !assertion.is_subject_assertion() && !assertion.is_subject_obscured() {
                    return Err(EnvelopeError::InvalidFormat)
                }

                match self.case() {
                    EnvelopeCase::Node { subject, assertions, .. } => {
                        if !assertions.iter().any(|a| a.digest() == assertion.digest()) {
                            let mut assertions = assertions.clone();
                            assertions.push(assertion);
                            Ok(Self::new_with_unchecked_assertions(subject.clone(), assertions))
                        } else {
                            Ok(self.clone())
                        }
                    },
                    _ => Ok(Self::new_with_unchecked_assertions(self.subject(), vec![assertion])),
                }
            },
            None => Ok(self.clone()),
        }
    }

    /// If the optional object is present, returns the result of adding the
    /// assertion to the envelope. Otherwise, returns the envelope unchanged.
    pub fn add_optional_assertion(&self, predicate: impl EnvelopeEncodable, object: Option<impl EnvelopeEncodable>) -> Self {
        if let Some(object) = object {
            self.add_assertion_envelope(Self::new_assertion(predicate, object)).unwrap()
        } else {
            self.clone()
        }
    }

    /// Returns a new `Envelope` with the given array of assertions added.
    ///
    /// - Parameter assertions: The assertions to add.
    pub fn add_assertions(&self, envelopes: &[Self]) -> Self {
        let mut e = self.clone();
        for envelope in envelopes {
            e = e.add_assertion_envelope(envelope.clone()).unwrap();
        }
        e.clone()
    }
}

/// Support for adding conditional assertions.
impl Envelope {
    /// If the condition is true, returns the result of adding the given assertion to the envelope.
    /// Otherwise, returns the envelope unchanged.
    pub fn add_assertion_if(&self, condition: bool, predicate: impl EnvelopeEncodable, object: impl EnvelopeEncodable) -> Self {
        if condition {
            self.add_assertion(predicate, object)
        } else {
            self.clone()
        }
    }

    /// If the condition is true, returns the result of adding the given assertion to the envelope.
    /// Otherwise, returns the envelope unchanged.
    pub fn add_assertion_envelope_if(&self, condition: bool, assertion_envelope: Self) -> Result<Self, EnvelopeError> {
        if condition {
            self.add_assertion_envelope(assertion_envelope)
        } else {
            Ok(self.clone())
        }
    }
}

#[cfg(feature = "salt")]
/// Support for adding assertions with salt.
impl Envelope {
    /// Returns the result of adding the given assertion to the envelope, optionally salting it.
    pub fn add_assertion_salted<P, O>(&self, predicate: P, object: O, salted: bool) -> Self
    where
        P: EnvelopeEncodable,
        O: EnvelopeEncodable,
    {
        let assertion = Self::new_assertion(predicate, object);
        self.add_optional_assertion_envelope_salted(Some(assertion), salted).unwrap()
    }

    /// Returns the result of adding the given assertion to the envelope, optionally salting it.
    ///
    /// The assertion envelope must be a valid assertion envelope, or an
    /// obscured variant (elided, encrypted, compressed) of one.
    pub fn add_assertion_envelope_salted(&self, assertion_envelope: Self, salted: bool) -> Result<Self, EnvelopeError> {
        self.add_optional_assertion_envelope_salted(Some(assertion_envelope), salted)
    }

    /// If the optional assertion is present, returns the result of adding it to
    /// the envelope, optionally salting it. Otherwise, returns the envelope unchanged.
    ///
    /// The assertion envelope must be a valid assertion envelope, or an
    /// obscured variant (elided, encrypted, compressed) of one.
    pub fn add_optional_assertion_envelope_salted(&self, assertion: Option<Self>, salted: bool) -> Result<Self, EnvelopeError> {
        match assertion {
            Some(assertion) => {
                if !assertion.is_subject_assertion() && !assertion.is_subject_obscured() {
                    return Err(EnvelopeError::InvalidFormat)
                }
                let envelope2 = if salted {
                    assertion.add_salt()
                } else {
                    assertion
                };

                match self.case() {
                    EnvelopeCase::Node { subject, assertions, .. } => {
                        if !assertions.iter().any(|a| a.digest() == envelope2.digest()) {
                            let mut assertions = assertions.clone();
                            assertions.push(envelope2);
                            Ok(Self::new_with_unchecked_assertions(subject.clone(), assertions))
                        } else {
                            Ok(self.clone())
                        }
                    },
                    _ => Ok(Self::new_with_unchecked_assertions(self.subject(), vec![envelope2])),
                }
            },
            None => Ok(self.clone()),
        }
    }

    pub fn add_assertions_salted(&self, assertions: &[Self], salted: bool) -> Self {
        let mut e = self.clone();
        for assertion in assertions {
            e = e.add_assertion_envelope_salted(assertion.clone(), salted).unwrap();
        }
        e.clone()
    }
}

/// Support for removing or replacing assertions.
impl Envelope {
    /// Returns a new envelope with the given assertion removed. If the assertion does
    /// not exist, returns the same envelope.
    pub fn remove_assertion(&self, target: Self) -> Self {
        let assertions = self.assertions();
        let target = target.digest();
        if let Some(index) = assertions.iter().position(|a| a.digest() == target) {
            let mut assertions = assertions.clone();
            assertions.remove(index);
            if assertions.is_empty() {
                self.subject()
            } else {
                Self::new_with_unchecked_assertions(self.subject(), assertions)
            }
        } else {
            self.clone()
        }
    }

    /// Returns a new envelope with the given assertion replaced by the provided one. If
    /// the targeted assertion does not exist, returns the same envelope.
    pub fn replace_assertion(&self, assertion: Self, new_assertion: Self) -> Result<Self, EnvelopeError> {
        self.remove_assertion(assertion).add_assertion_envelope(new_assertion)
    }

    /// Returns a new envelope with its subject replaced by the provided one.
    pub fn replace_subject(&self, subject: Self) -> Self {
        self.assertions().iter().fold(subject, |e, a| e.add_assertion_envelope(a).unwrap())
    }
}