Port the push rule classes to Rust. (#13768)

4 files changed, 854 insertions, 2 deletions

diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index deddf3cec2..8dc5f93ff1 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -18,7 +18,15 @@ crate-type = ["cdylib"]
 name = "synapse.synapse_rust"
 
 [dependencies]
-pyo3 = { version = "0.16.5", features = ["extension-module", "macros", "abi3", "abi3-py37"] }
+anyhow = "1.0.63"
+lazy_static = "1.4.0"
+log = "0.4.17"
+pyo3 = { version = "0.17.1", features = ["extension-module", "macros", "anyhow", "abi3", "abi3-py37"] }
+pyo3-log = "0.7.0"
+pythonize = "0.17.0"
+regex = "1.6.0"
+serde = { version = "1.0.144", features = ["derive"] }
+serde_json = "1.0.85"
 
 [build-dependencies]
 blake2 = "0.10.4"
diff --git a/rust/src/lib.rs b/rust/src/lib.rs
index ba42465fb8..c7b60e58a7 100644
--- a/rust/src/lib.rs
+++ b/rust/src/lib.rs
@@ -1,5 +1,7 @@
 use pyo3::prelude::*;
 
+pub mod push;
+
 /// Returns the hash of all the rust source files at the time it was compiled.
 ///
 /// Used by python to detect if the rust library is outdated.
@@ -17,8 +19,13 @@ fn sum_as_string(a: usize, b: usize) -> PyResult<String> {
 
 /// The entry point for defining the Python module.
 #[pymodule]
-fn synapse_rust(_py: Python<'_>, m: &PyModule) -> PyResult<()> {
+fn synapse_rust(py: Python<'_>, m: &PyModule) -> PyResult<()> {
+    pyo3_log::init();
+
     m.add_function(wrap_pyfunction!(sum_as_string, m)?)?;
     m.add_function(wrap_pyfunction!(get_rust_file_digest, m)?)?;
+
+    push::register_module(py, m)?;
+
     Ok(())
 }
diff --git a/rust/src/push/base_rules.rs b/rust/src/push/base_rules.rs
new file mode 100644
index 0000000000..7c62bc4849
--- /dev/null
+++ b/rust/src/push/base_rules.rs
@@ -0,0 +1,335 @@
+// Copyright 2022 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Contains the definitions of the "base" push rules.
+
+use std::borrow::Cow;
+use std::collections::HashMap;
+
+use lazy_static::lazy_static;
+use serde_json::Value;
+
+use super::KnownCondition;
+use crate::push::Action;
+use crate::push::Condition;
+use crate::push::EventMatchCondition;
+use crate::push::PushRule;
+use crate::push::SetTweak;
+use crate::push::TweakValue;
+
+const HIGHLIGHT_ACTION: Action = Action::SetTweak(SetTweak {
+    set_tweak: Cow::Borrowed("highlight"),
+    value: None,
+    other_keys: Value::Null,
+});
+
+const HIGHLIGHT_FALSE_ACTION: Action = Action::SetTweak(SetTweak {
+    set_tweak: Cow::Borrowed("highlight"),
+    value: Some(TweakValue::Other(Value::Bool(false))),
+    other_keys: Value::Null,
+});
+
+const SOUND_ACTION: Action = Action::SetTweak(SetTweak {
+    set_tweak: Cow::Borrowed("sound"),
+    value: Some(TweakValue::String(Cow::Borrowed("default"))),
+    other_keys: Value::Null,
+});
+
+const RING_ACTION: Action = Action::SetTweak(SetTweak {
+    set_tweak: Cow::Borrowed("sound"),
+    value: Some(TweakValue::String(Cow::Borrowed("ring"))),
+    other_keys: Value::Null,
+});
+
+pub const BASE_PREPEND_OVERRIDE_RULES: &[PushRule] = &[PushRule {
+    rule_id: Cow::Borrowed("global/override/.m.rule.master"),
+    priority_class: 5,
+    conditions: Cow::Borrowed(&[]),
+    actions: Cow::Borrowed(&[Action::DontNotify]),
+    default: true,
+    default_enabled: false,
+}];
+
+pub const BASE_APPEND_OVERRIDE_RULES: &[PushRule] = &[
+    PushRule {
+        rule_id: Cow::Borrowed("global/override/.m.rule.suppress_notices"),
+        priority_class: 5,
+        conditions: Cow::Borrowed(&[Condition::Known(KnownCondition::EventMatch(
+            EventMatchCondition {
+                key: Cow::Borrowed("content.msgtype"),
+                pattern: Some(Cow::Borrowed("m.notice")),
+                pattern_type: None,
+            },
+        ))]),
+        actions: Cow::Borrowed(&[Action::DontNotify]),
+        default: true,
+        default_enabled: true,
+    },
+    PushRule {
+        rule_id: Cow::Borrowed("global/override/.m.rule.invite_for_me"),
+        priority_class: 5,
+        conditions: Cow::Borrowed(&[
+            Condition::Known(KnownCondition::EventMatch(EventMatchCondition {
+                key: Cow::Borrowed("type"),
+                pattern: Some(Cow::Borrowed("m.room.member")),
+                pattern_type: None,
+            })),
+            Condition::Known(KnownCondition::EventMatch(EventMatchCondition {
+                key: Cow::Borrowed("content.membership"),
+                pattern: Some(Cow::Borrowed("invite")),
+                pattern_type: None,
+            })),
+            Condition::Known(KnownCondition::EventMatch(EventMatchCondition {
+                key: Cow::Borrowed("state_key"),
+                pattern: None,
+                pattern_type: Some(Cow::Borrowed("user_id")),
+            })),
+        ]),
+        actions: Cow::Borrowed(&[Action::Notify, HIGHLIGHT_FALSE_ACTION, SOUND_ACTION]),
+        default: true,
+        default_enabled: true,
+    },
+    PushRule {
+        rule_id: Cow::Borrowed("global/override/.m.rule.member_event"),
+        priority_class: 5,
+        conditions: Cow::Borrowed(&[Condition::Known(KnownCondition::EventMatch(
+            EventMatchCondition {
+                key: Cow::Borrowed("type"),
+                pattern: Some(Cow::Borrowed("m.room.member")),
+                pattern_type: None,
+            },
+        ))]),
+        actions: Cow::Borrowed(&[Action::DontNotify]),
+        default: true,
+        default_enabled: true,
+    },
+    PushRule {
+        rule_id: Cow::Borrowed("global/override/.m.rule.contains_display_name"),
+        priority_class: 5,
+        conditions: Cow::Borrowed(&[Condition::Known(KnownCondition::ContainsDisplayName)]),
+        actions: Cow::Borrowed(&[Action::Notify, HIGHLIGHT_ACTION, SOUND_ACTION]),
+        default: true,
+        default_enabled: true,
+    },
+    PushRule {
+        rule_id: Cow::Borrowed("global/override/.m.rule.roomnotif"),
+        priority_class: 5,
+        conditions: Cow::Borrowed(&[
+            Condition::Known(KnownCondition::SenderNotificationPermission {
+                key: Cow::Borrowed("room"),
+            }),
+            Condition::Known(KnownCondition::EventMatch(EventMatchCondition {
+                key: Cow::Borrowed("content.body"),
+                pattern: Some(Cow::Borrowed("@room")),
+                pattern_type: None,
+            })),
+        ]),
+        actions: Cow::Borrowed(&[Action::Notify, HIGHLIGHT_ACTION]),
+        default: true,
+        default_enabled: true,
+    },
+    PushRule {
+        rule_id: Cow::Borrowed("global/override/.m.rule.tombstone"),
+        priority_class: 5,
+        conditions: Cow::Borrowed(&[
+            Condition::Known(KnownCondition::EventMatch(EventMatchCondition {
+                key: Cow::Borrowed("type"),
+                pattern: Some(Cow::Borrowed("m.room.tombstone")),
+                pattern_type: None,
+            })),
+            Condition::Known(KnownCondition::EventMatch(EventMatchCondition {
+                key: Cow::Borrowed("state_key"),
+                pattern: Some(Cow::Borrowed("")),
+                pattern_type: None,
+            })),
+        ]),
+        actions: Cow::Borrowed(&[Action::Notify, HIGHLIGHT_ACTION]),
+        default: true,
+        default_enabled: true,
+    },
+    PushRule {
+        rule_id: Cow::Borrowed("global/override/.m.rule.reaction"),
+        priority_class: 5,
+        conditions: Cow::Borrowed(&[Condition::Known(KnownCondition::EventMatch(
+            EventMatchCondition {
+                key: Cow::Borrowed("type"),
+                pattern: Some(Cow::Borrowed("m.reaction")),
+                pattern_type: None,
+            },
+        ))]),
+        actions: Cow::Borrowed(&[Action::DontNotify]),
+        default: true,
+        default_enabled: true,
+    },
+    PushRule {
+        rule_id: Cow::Borrowed("global/override/.org.matrix.msc3786.rule.room.server_acl"),
+        priority_class: 5,
+        conditions: Cow::Borrowed(&[
+            Condition::Known(KnownCondition::EventMatch(EventMatchCondition {
+                key: Cow::Borrowed("type"),
+                pattern: Some(Cow::Borrowed("m.room.server_acl")),
+                pattern_type: None,
+            })),
+            Condition::Known(KnownCondition::EventMatch(EventMatchCondition {
+                key: Cow::Borrowed("state_key"),
+                pattern: Some(Cow::Borrowed("")),
+                pattern_type: None,
+            })),
+        ]),
+        actions: Cow::Borrowed(&[]),
+        default: true,
+        default_enabled: true,
+    },
+];
+
+pub const BASE_APPEND_CONTENT_RULES: &[PushRule] = &[PushRule {
+    rule_id: Cow::Borrowed("global/content/.m.rule.contains_user_name"),
+    priority_class: 4,
+    conditions: Cow::Borrowed(&[Condition::Known(KnownCondition::EventMatch(
+        EventMatchCondition {
+            key: Cow::Borrowed("content.body"),
+            pattern: None,
+            pattern_type: Some(Cow::Borrowed("user_localpart")),
+        },
+    ))]),
+    actions: Cow::Borrowed(&[Action::Notify, HIGHLIGHT_ACTION, SOUND_ACTION]),
+    default: true,
+    default_enabled: true,
+}];
+
+pub const BASE_APPEND_UNDERRIDE_RULES: &[PushRule] = &[
+    PushRule {
+        rule_id: Cow::Borrowed("global/underride/.m.rule.call"),
+        priority_class: 1,
+        conditions: Cow::Borrowed(&[Condition::Known(KnownCondition::EventMatch(
+            EventMatchCondition {
+                key: Cow::Borrowed("type"),
+                pattern: Some(Cow::Borrowed("m.call.invite")),
+                pattern_type: None,
+            },
+        ))]),
+        actions: Cow::Borrowed(&[Action::Notify, RING_ACTION, HIGHLIGHT_FALSE_ACTION]),
+        default: true,
+        default_enabled: true,
+    },
+    PushRule {
+        rule_id: Cow::Borrowed("global/underride/.m.rule.room_one_to_one"),
+        priority_class: 1,
+        conditions: Cow::Borrowed(&[
+            Condition::Known(KnownCondition::EventMatch(EventMatchCondition {
+                key: Cow::Borrowed("type"),
+                pattern: Some(Cow::Borrowed("m.room.message")),
+                pattern_type: None,
+            })),
+            Condition::Known(KnownCondition::RoomMemberCount {
+                is: Some(Cow::Borrowed("2")),
+            }),
+        ]),
+        actions: Cow::Borrowed(&[Action::Notify, SOUND_ACTION, HIGHLIGHT_FALSE_ACTION]),
+        default: true,
+        default_enabled: true,
+    },
+    PushRule {
+        rule_id: Cow::Borrowed("global/underride/.m.rule.encrypted_room_one_to_one"),
+        priority_class: 1,
+        conditions: Cow::Borrowed(&[
+            Condition::Known(KnownCondition::EventMatch(EventMatchCondition {
+                key: Cow::Borrowed("type"),
+                pattern: Some(Cow::Borrowed("m.room.encrypted")),
+                pattern_type: None,
+            })),
+            Condition::Known(KnownCondition::RoomMemberCount {
+                is: Some(Cow::Borrowed("2")),
+            }),
+        ]),
+        actions: Cow::Borrowed(&[Action::Notify, SOUND_ACTION, HIGHLIGHT_FALSE_ACTION]),
+        default: true,
+        default_enabled: true,
+    },
+    PushRule {
+        rule_id: Cow::Borrowed("global/underride/.org.matrix.msc3772.thread_reply"),
+        priority_class: 1,
+        conditions: Cow::Borrowed(&[Condition::Known(KnownCondition::RelationMatch {
+            rel_type: Cow::Borrowed("m.thread"),
+            sender: None,
+            sender_type: Some(Cow::Borrowed("user_id")),
+        })]),
+        actions: Cow::Borrowed(&[Action::Notify, HIGHLIGHT_FALSE_ACTION]),
+        default: true,
+        default_enabled: true,
+    },
+    PushRule {
+        rule_id: Cow::Borrowed("global/underride/.m.rule.message"),
+        priority_class: 1,
+        conditions: Cow::Borrowed(&[Condition::Known(KnownCondition::EventMatch(
+            EventMatchCondition {
+                key: Cow::Borrowed("type"),
+                pattern: Some(Cow::Borrowed("m.room.message")),
+                pattern_type: None,
+            },
+        ))]),
+        actions: Cow::Borrowed(&[Action::Notify, HIGHLIGHT_FALSE_ACTION]),
+        default: true,
+        default_enabled: true,
+    },
+    PushRule {
+        rule_id: Cow::Borrowed("global/underride/.m.rule.encrypted"),
+        priority_class: 1,
+        conditions: Cow::Borrowed(&[Condition::Known(KnownCondition::EventMatch(
+            EventMatchCondition {
+                key: Cow::Borrowed("type"),
+                pattern: Some(Cow::Borrowed("m.room.encrypted")),
+                pattern_type: None,
+            },
+        ))]),
+        actions: Cow::Borrowed(&[Action::Notify, HIGHLIGHT_FALSE_ACTION]),
+        default: true,
+        default_enabled: true,
+    },
+    PushRule {
+        rule_id: Cow::Borrowed("global/underride/.im.vector.jitsi"),
+        priority_class: 1,
+        conditions: Cow::Borrowed(&[
+            Condition::Known(KnownCondition::EventMatch(EventMatchCondition {
+                key: Cow::Borrowed("type"),
+                pattern: Some(Cow::Borrowed("im.vector.modular.widgets")),
+                pattern_type: None,
+            })),
+            Condition::Known(KnownCondition::EventMatch(EventMatchCondition {
+                key: Cow::Borrowed("content.type"),
+                pattern: Some(Cow::Borrowed("jitsi")),
+                pattern_type: None,
+            })),
+            Condition::Known(KnownCondition::EventMatch(EventMatchCondition {
+                key: Cow::Borrowed("state_key"),
+                pattern: Some(Cow::Borrowed("*")),
+                pattern_type: None,
+            })),
+        ]),
+        actions: Cow::Borrowed(&[Action::Notify, HIGHLIGHT_FALSE_ACTION]),
+        default: true,
+        default_enabled: true,
+    },
+];
+
+lazy_static! {
+    pub static ref BASE_RULES_BY_ID: HashMap<&'static str, &'static PushRule> =
+        BASE_PREPEND_OVERRIDE_RULES
+            .iter()
+            .chain(BASE_APPEND_OVERRIDE_RULES.iter())
+            .chain(BASE_APPEND_CONTENT_RULES.iter())
+            .chain(BASE_APPEND_UNDERRIDE_RULES.iter())
+            .map(|rule| { (&*rule.rule_id, rule) })
+            .collect();
+}
diff --git a/rust/src/push/mod.rs b/rust/src/push/mod.rs
new file mode 100644
index 0000000000..de6764e7c5
--- /dev/null
+++ b/rust/src/push/mod.rs
@@ -0,0 +1,502 @@
+// Copyright 2022 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! An implementation of Matrix push rules.
+//!
+//! The `Cow<_>` type is used extensively within this module to allow creating
+//! the base rules as constants (in Rust constants can't require explicit
+//! allocation atm).
+//!
+//! ---
+//!
+//! Push rules is the system used to determine which events trigger a push (and a
+//! bump in notification counts).
+//!
+//! This consists of a list of "push rules" for each user, where a push rule is a
+//! pair of "conditions" and "actions". When a user receives an event Synapse
+//! iterates over the list of push rules until it finds one where all the conditions
+//! match the event, at which point "actions" describe the outcome (e.g. notify,
+//! highlight, etc).
+//!
+//! Push rules are split up into 5 different "kinds" (aka "priority classes"), which
+//! are run in order:
+//!     1. Override — highest priority rules, e.g. always ignore notices
+//!     2. Content — content specific rules, e.g. @ notifications
+//!     3. Room — per room rules, e.g. enable/disable notifications for all messages
+//!        in a room
+//!     4. Sender — per sender rules, e.g. never notify for messages from a given
+//!        user
+//!     5. Underride — the lowest priority "default" rules, e.g. notify for every
+//!        message.
+//!
+//! The set of "base rules" are the list of rules that every user has by default. A
+//! user can modify their copy of the push rules in one of three ways:
+//!
+//!     1. Adding a new push rule of a certain kind
+//!     2. Changing the actions of a base rule
+//!     3. Enabling/disabling a base rule.
+//!
+//! The base rules are split into whether they come before or after a particular
+//! kind, so the order of push rule evaluation would be: base rules for before
+//! "override" kind, user defined "override" rules, base rules after "override"
+//! kind, etc, etc.
+
+use std::borrow::Cow;
+use std::collections::{BTreeMap, HashMap, HashSet};
+
+use anyhow::{Context, Error};
+use log::warn;
+use pyo3::prelude::*;
+use pythonize::pythonize;
+use serde::de::Error as _;
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+
+mod base_rules;
+
+/// Called when registering modules with python.
+pub fn register_module(py: Python<'_>, m: &PyModule) -> PyResult<()> {
+    let child_module = PyModule::new(py, "push")?;
+    child_module.add_class::<PushRule>()?;
+    child_module.add_class::<PushRules>()?;
+    child_module.add_class::<FilteredPushRules>()?;
+    child_module.add_function(wrap_pyfunction!(get_base_rule_ids, m)?)?;
+
+    m.add_submodule(child_module)?;
+
+    // We need to manually add the module to sys.modules to make `from
+    // synapse.synapse_rust import push` work.
+    py.import("sys")?
+        .getattr("modules")?
+        .set_item("synapse.synapse_rust.push", child_module)?;
+
+    Ok(())
+}
+
+#[pyfunction]
+fn get_base_rule_ids() -> HashSet<&'static str> {
+    base_rules::BASE_RULES_BY_ID.keys().copied().collect()
+}
+
+/// A single push rule for a user.
+#[derive(Debug, Clone)]
+#[pyclass(frozen)]
+pub struct PushRule {
+    /// A unique ID for this rule
+    pub rule_id: Cow<'static, str>,
+    /// The "kind" of push rule this is (see `PRIORITY_CLASS_MAP` in Python)
+    #[pyo3(get)]
+    pub priority_class: i32,
+    /// The conditions that must all match for actions to be applied
+    pub conditions: Cow<'static, [Condition]>,
+    /// The actions to apply if all conditions are met
+    pub actions: Cow<'static, [Action]>,
+    /// Whether this is a base rule
+    #[pyo3(get)]
+    pub default: bool,
+    /// Whether this is enabled by default
+    #[pyo3(get)]
+    pub default_enabled: bool,
+}
+
+#[pymethods]
+impl PushRule {
+    #[staticmethod]
+    pub fn from_db(
+        rule_id: String,
+        priority_class: i32,
+        conditions: &str,
+        actions: &str,
+    ) -> Result<PushRule, Error> {
+        let conditions = serde_json::from_str(conditions).context("parsing conditions")?;
+        let actions = serde_json::from_str(actions).context("parsing actions")?;
+
+        Ok(PushRule {
+            rule_id: Cow::Owned(rule_id),
+            priority_class,
+            conditions,
+            actions,
+            default: false,
+            default_enabled: true,
+        })
+    }
+
+    #[getter]
+    fn rule_id(&self) -> &str {
+        &self.rule_id
+    }
+
+    #[getter]
+    fn actions(&self) -> Vec<Action> {
+        self.actions.clone().into_owned()
+    }
+
+    #[getter]
+    fn conditions(&self) -> Vec<Condition> {
+        self.conditions.clone().into_owned()
+    }
+
+    fn __repr__(&self) -> String {
+        format!(
+            "<PushRule rule_id={}, conditions={:?}, actions={:?}>",
+            self.rule_id, self.conditions, self.actions
+        )
+    }
+}
+
+/// The "action" Synapse should perform for a matching push rule.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum Action {
+    DontNotify,
+    Notify,
+    Coalesce,
+    SetTweak(SetTweak),
+
+    // An unrecognized custom action.
+    Unknown(Value),
+}
+
+impl IntoPy<PyObject> for Action {
+    fn into_py(self, py: Python<'_>) -> PyObject {
+        // When we pass the `Action` struct to Python we want it to be converted
+        // to a dict. We use `pythonize`, which converts the struct using the
+        // `serde` serialization.
+        pythonize(py, &self).expect("valid action")
+    }
+}
+
+/// The body of a `SetTweak` push action.
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
+pub struct SetTweak {
+    set_tweak: Cow<'static, str>,
+
+    #[serde(skip_serializing_if = "Option::is_none")]
+    value: Option<TweakValue>,
+
+    // This picks up any other fields that may have been added by clients.
+    // These get added when we convert the `Action` to a python object.
+    #[serde(flatten)]
+    other_keys: Value,
+}
+
+/// The value of a `set_tweak`.
+///
+/// We need this (rather than using `TweakValue` directly) so that we can use
+/// `&'static str` in the value when defining the constant base rules.
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
+#[serde(untagged)]
+pub enum TweakValue {
+    String(Cow<'static, str>),
+    Other(Value),
+}
+
+impl Serialize for Action {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        match self {
+            Action::DontNotify => serializer.serialize_str("dont_notify"),
+            Action::Notify => serializer.serialize_str("notify"),
+            Action::Coalesce => serializer.serialize_str("coalesce"),
+            Action::SetTweak(tweak) => tweak.serialize(serializer),
+            Action::Unknown(value) => value.serialize(serializer),
+        }
+    }
+}
+
+/// Simple helper class for deserializing Action from JSON.
+#[derive(Deserialize)]
+#[serde(untagged)]
+enum ActionDeserializeHelper {
+    Str(String),
+    SetTweak(SetTweak),
+    Unknown(Value),
+}
+
+impl<'de> Deserialize<'de> for Action {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let helper: ActionDeserializeHelper = Deserialize::deserialize(deserializer)?;
+        match helper {
+            ActionDeserializeHelper::Str(s) => match &*s {
+                "dont_notify" => Ok(Action::DontNotify),
+                "notify" => Ok(Action::Notify),
+                "coalesce" => Ok(Action::Coalesce),
+                _ => Err(D::Error::custom("unrecognized action")),
+            },
+            ActionDeserializeHelper::SetTweak(set_tweak) => Ok(Action::SetTweak(set_tweak)),
+            ActionDeserializeHelper::Unknown(value) => Ok(Action::Unknown(value)),
+        }
+    }
+}
+
+/// A condition used in push rules to match against an event.
+///
+/// We need this split as `serde` doesn't give us the ability to have a
+/// "catchall" variant in tagged enums.
+#[derive(Serialize, Deserialize, Debug, Clone)]
+#[serde(untagged)]
+pub enum Condition {
+    /// A recognized condition that we can match against
+    Known(KnownCondition),
+    /// An unrecognized condition that we ignore.
+    Unknown(Value),
+}
+
+/// The set of "known" conditions that we can handle.
+#[derive(Serialize, Deserialize, Debug, Clone)]
+#[serde(rename_all = "snake_case")]
+#[serde(tag = "kind")]
+pub enum KnownCondition {
+    EventMatch(EventMatchCondition),
+    ContainsDisplayName,
+    RoomMemberCount {
+        #[serde(skip_serializing_if = "Option::is_none")]
+        is: Option<Cow<'static, str>>,
+    },
+    SenderNotificationPermission {
+        key: Cow<'static, str>,
+    },
+    #[serde(rename = "org.matrix.msc3772.relation_match")]
+    RelationMatch {
+        rel_type: Cow<'static, str>,
+        #[serde(skip_serializing_if = "Option::is_none")]
+        sender: Option<Cow<'static, str>>,
+        #[serde(skip_serializing_if = "Option::is_none")]
+        sender_type: Option<Cow<'static, str>>,
+    },
+}
+
+impl IntoPy<PyObject> for Condition {
+    fn into_py(self, py: Python<'_>) -> PyObject {
+        pythonize(py, &self).expect("valid condition")
+    }
+}
+
+/// The body of a [`Condition::EventMatch`]
+#[derive(Serialize, Deserialize, Debug, Clone)]
+pub struct EventMatchCondition {
+    key: Cow<'static, str>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pattern: Option<Cow<'static, str>>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pattern_type: Option<Cow<'static, str>>,
+}
+
+/// The collection of push rules for a user.
+#[derive(Debug, Clone, Default)]
+#[pyclass(frozen)]
+struct PushRules {
+    /// Custom push rules that override a base rule.
+    overridden_base_rules: HashMap<Cow<'static, str>, PushRule>,
+
+    /// Custom rules that come between the prepend/append override base rules.
+    override_rules: Vec<PushRule>,
+    /// Custom rules that come before the base content rules.
+    content: Vec<PushRule>,
+    /// Custom rules that come before the base room rules.
+    room: Vec<PushRule>,
+    /// Custom rules that come before the base sender rules.
+    sender: Vec<PushRule>,
+    /// Custom rules that come before the base underride rules.
+    underride: Vec<PushRule>,
+}
+
+#[pymethods]
+impl PushRules {
+    #[new]
+    fn new(rules: Vec<PushRule>) -> PushRules {
+        let mut push_rules: PushRules = Default::default();
+
+        for rule in rules {
+            if let Some(&o) = base_rules::BASE_RULES_BY_ID.get(&*rule.rule_id) {
+                push_rules.overridden_base_rules.insert(
+                    rule.rule_id.clone(),
+                    PushRule {
+                        actions: rule.actions.clone(),
+                        ..o.clone()
+                    },
+                );
+
+                continue;
+            }
+
+            match rule.priority_class {
+                5 => push_rules.override_rules.push(rule),
+                4 => push_rules.content.push(rule),
+                3 => push_rules.room.push(rule),
+                2 => push_rules.sender.push(rule),
+                1 => push_rules.underride.push(rule),
+                _ => {
+                    warn!(
+                        "Unrecognized priority class for rule {}: {}",
+                        rule.rule_id, rule.priority_class
+                    );
+                }
+            }
+        }
+
+        push_rules
+    }
+
+    /// Returns the list of all rules, including base rules, in the order they
+    /// should be executed in.
+    fn rules(&self) -> Vec<PushRule> {
+        self.iter().cloned().collect()
+    }
+}
+
+impl PushRules {
+    /// Iterates over all the rules, including base rules, in the order they
+    /// should be executed in.
+    pub fn iter(&self) -> impl Iterator<Item = &PushRule> {
+        base_rules::BASE_PREPEND_OVERRIDE_RULES
+            .iter()
+            .chain(self.override_rules.iter())
+            .chain(base_rules::BASE_APPEND_OVERRIDE_RULES.iter())
+            .chain(self.content.iter())
+            .chain(base_rules::BASE_APPEND_CONTENT_RULES.iter())
+            .chain(self.room.iter())
+            .chain(self.sender.iter())
+            .chain(self.underride.iter())
+            .chain(base_rules::BASE_APPEND_UNDERRIDE_RULES.iter())
+            .map(|rule| {
+                self.overridden_base_rules
+                    .get(&*rule.rule_id)
+                    .unwrap_or(rule)
+            })
+    }
+}
+
+/// A wrapper around `PushRules` that checks the enabled state of rules and
+/// filters out disabled experimental rules.
+#[derive(Debug, Clone, Default)]
+#[pyclass(frozen)]
+pub struct FilteredPushRules {
+    push_rules: PushRules,
+    enabled_map: BTreeMap<String, bool>,
+    msc3786_enabled: bool,
+    msc3772_enabled: bool,
+}
+
+#[pymethods]
+impl FilteredPushRules {
+    #[new]
+    fn py_new(
+        push_rules: PushRules,
+        enabled_map: BTreeMap<String, bool>,
+        msc3786_enabled: bool,
+        msc3772_enabled: bool,
+    ) -> Self {
+        Self {
+            push_rules,
+            enabled_map,
+            msc3786_enabled,
+            msc3772_enabled,
+        }
+    }
+
+    /// Returns the list of all rules and their enabled state, including base
+    /// rules, in the order they should be executed in.
+    fn rules(&self) -> Vec<(PushRule, bool)> {
+        self.iter().map(|(r, e)| (r.clone(), e)).collect()
+    }
+}
+
+impl FilteredPushRules {
+    /// Iterates over all the rules and their enabled state, including base
+    /// rules, in the order they should be executed in.
+    fn iter(&self) -> impl Iterator<Item = (&PushRule, bool)> {
+        self.push_rules
+            .iter()
+            .filter(|rule| {
+                // Ignore disabled experimental push rules
+                if !self.msc3786_enabled
+                    && rule.rule_id == "global/override/.org.matrix.msc3786.rule.room.server_acl"
+                {
+                    return false;
+                }
+
+                if !self.msc3772_enabled
+                    && rule.rule_id == "global/underride/.org.matrix.msc3772.thread_reply"
+                {
+                    return false;
+                }
+
+                true
+            })
+            .map(|r| {
+                let enabled = *self
+                    .enabled_map
+                    .get(&*r.rule_id)
+                    .unwrap_or(&r.default_enabled);
+                (r, enabled)
+            })
+    }
+}
+
+#[test]
+fn test_serialize_condition() {
+    let condition = Condition::Known(KnownCondition::EventMatch(EventMatchCondition {
+        key: "content.body".into(),
+        pattern: Some("coffee".into()),
+        pattern_type: None,
+    }));
+
+    let json = serde_json::to_string(&condition).unwrap();
+    assert_eq!(
+        json,
+        r#"{"kind":"event_match","key":"content.body","pattern":"coffee"}"#
+    )
+}
+
+#[test]
+fn test_deserialize_condition() {
+    let json = r#"{"kind":"event_match","key":"content.body","pattern":"coffee"}"#;
+
+    let _: Condition = serde_json::from_str(json).unwrap();
+}
+
+#[test]
+fn test_deserialize_custom_condition() {
+    let json = r#"{"kind":"custom_tag"}"#;
+
+    let condition: Condition = serde_json::from_str(json).unwrap();
+    assert!(matches!(condition, Condition::Unknown(_)));
+
+    let new_json = serde_json::to_string(&condition).unwrap();
+    assert_eq!(json, new_json);
+}
+
+#[test]
+fn test_deserialize_action() {
+    let _: Action = serde_json::from_str(r#""notify""#).unwrap();
+    let _: Action = serde_json::from_str(r#""dont_notify""#).unwrap();
+    let _: Action = serde_json::from_str(r#""coalesce""#).unwrap();
+    let _: Action = serde_json::from_str(r#"{"set_tweak": "highlight"}"#).unwrap();
+}
+
+#[test]
+fn test_custom_action() {
+    let json = r#"{"some_custom":"action_fields"}"#;
+
+    let action: Action = serde_json::from_str(json).unwrap();
+    assert!(matches!(action, Action::Unknown(_)));
+
+    let new_json = serde_json::to_string(&action).unwrap();
+    assert_eq!(json, new_json);
+}