From fe554c158cb2eb84aec264dba3aa63ed9d63665e Mon Sep 17 00:00:00 2001
From: Georgios Konstantopoulos <me@gakonst.com>
Date: Mon, 25 May 2020 00:15:45 +0300
Subject: [PATCH] wip: filters

---
 src/lib.rs       |  3 ++-
 src/types/log.rs | 64 +++++++++++++++++++++++++++++++++++++++++++++++-
 src/types/mod.rs |  2 +-
 src/utils.rs     | 11 +++++++++
 4 files changed, 77 insertions(+), 3 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 549fdd38..8730b1a6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -28,4 +28,5 @@ pub mod types;
 /// Re-export solc for convenience
 pub use solc;
 
-mod utils;
+/// Various utilities
+pub mod utils;
diff --git a/src/types/log.rs b/src/types/log.rs
index 3865bba1..c2c15b12 100644
--- a/src/types/log.rs
+++ b/src/types/log.rs
@@ -1,4 +1,4 @@
-use crate::types::{Address, Bytes, H256, U256, U64};
+use crate::types::{Address, BlockNumber, Bytes, H256, U256, U64};
 use serde::{Deserialize, Serialize};
 
 /// A log produced by a transaction.
@@ -49,3 +49,65 @@ pub struct Log {
     /// false if its a valid log.
     pub removed: Option<bool>,
 }
+
+/// Filter
+#[derive(Default, Debug, PartialEq, Clone, Serialize)]
+pub struct Filter {
+    /// From Block
+    #[serde(rename = "fromBlock", skip_serializing_if = "Option::is_none")]
+    from_block: Option<BlockNumber>,
+    /// To Block
+    #[serde(rename = "toBlock", skip_serializing_if = "Option::is_none")]
+    to_block: Option<BlockNumber>,
+    /// Address
+    #[serde(skip_serializing_if = "Option::is_none")]
+    address: Option<ValueOrArray<Address>>,
+    /// Topics
+    #[serde(skip_serializing_if = "Option::is_none")]
+    topics: Option<Vec<Option<ValueOrArray<H256>>>>,
+    /// Limit
+    #[serde(skip_serializing_if = "Option::is_none")]
+    limit: Option<usize>,
+}
+
+impl Filter {
+    pub fn from_block<T: Into<BlockNumber>>(mut self, block: BlockNumber) -> Self {
+        self.from_block = Some(block.into());
+        self
+    }
+
+    pub fn to_block<T: Into<BlockNumber>>(mut self, block: BlockNumber) -> Self {
+        self.to_block = Some(block.into());
+        self
+    }
+
+    // pub fn address<T: Into<Address>>(mut self, block: BlockNumber) -> Self {
+    //     self.to_block = Some(block.into());
+    //     self
+    // }
+    pub fn limit(mut self, limit: usize) -> Self {
+        self.limit = Some(limit);
+        self
+    }
+}
+
+#[derive(Debug, PartialEq, Clone)]
+pub enum ValueOrArray<T> {
+    Value(T),
+    Array(Vec<T>),
+}
+
+impl<T> Serialize for ValueOrArray<T>
+where
+    T: Serialize,
+{
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        match self {
+            ValueOrArray::Value(inner) => inner.serialize(serializer),
+            ValueOrArray::Array(inner) => inner.serialize(serializer),
+        }
+    }
+}
diff --git a/src/types/mod.rs b/src/types/mod.rs
index e903cc49..3dffa088 100644
--- a/src/types/mod.rs
+++ b/src/types/mod.rs
@@ -20,4 +20,4 @@ mod block;
 pub use block::{Block, BlockId, BlockNumber};
 
 mod log;
-pub use log::Log;
+pub use log::{Filter, Log};
diff --git a/src/utils.rs b/src/utils.rs
index c8e5551d..7db0cd0e 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -31,6 +31,17 @@ pub fn keccak256(bytes: &[u8]) -> [u8; 32] {
     output
 }
 
+/// Gets the first 4 bytes
+pub fn id(name: &str) -> [u8; 4] {
+    let mut output = [0u8; 4];
+
+    let mut hasher = Keccak::v256();
+    hasher.update(name.as_bytes());
+    hasher.finalize(&mut output);
+
+    output
+}
+
 /// Serialize a type. Panics if the type is returns error during serialization.
 pub fn serialize<T: serde::Serialize>(t: &T) -> serde_json::Value {
     serde_json::to_value(t).expect("Types never fail to serialize.")