reifydb-core 0.9.0

// SPDX-License-Identifier: Apache-2.0
// Copyright (c) 2026 ReifyDB

use std::collections::Bound;

use reifydb_codec::key::{
	deserializer::KeyDeserializer,
	encoded::{EncodedKey, EncodedKeyRange},
	serializer::KeySerializer,
};

use super::{EncodableKey, EncodableKeyRange, KeyKind};
use crate::{
	interface::catalog::{
		id::{IndexId, PrimaryKeyId},
		object::ObjectId,
	},
	key::catalog::{KeyDeserializerCatalogExt, KeySerializerCatalogExt},
};

#[derive(Debug, Clone, PartialEq)]
pub struct IndexKey {
	pub object: ObjectId,
	pub index: IndexId,
}

impl EncodableKey for IndexKey {
	const KIND: KeyKind = KeyKind::Index;

	fn encode(&self) -> EncodedKey {
		let mut serializer = KeySerializer::with_capacity(18);
		serializer.extend_u8(Self::KIND as u8).extend_object_id(self.object).extend_u64(self.index);
		serializer.to_encoded_key()
	}

	fn decode(key: &EncodedKey) -> Option<Self> {
		let mut de = KeyDeserializer::from_bytes(key.as_slice());

		let kind: KeyKind = de.read_u8().ok()?.try_into().ok()?;
		if kind != Self::KIND {
			return None;
		}

		let object = de.read_object_id().ok()?;
		let index_value = de.read_u64().ok()?;

		Some(Self {
			object,
			index: IndexId::Primary(PrimaryKeyId(index_value)),
		})
	}
}

#[derive(Debug, Clone, PartialEq)]
pub struct ObjectIndexKeyRange {
	pub object: ObjectId,
}

impl ObjectIndexKeyRange {
	fn decode_key(key: &EncodedKey) -> Option<Self> {
		let mut de = KeyDeserializer::from_bytes(key.as_slice());

		let kind: KeyKind = de.read_u8().ok()?.try_into().ok()?;
		if kind != Self::KIND {
			return None;
		}

		let object = de.read_object_id().ok()?;

		Some(ObjectIndexKeyRange {
			object,
		})
	}
}

impl EncodableKeyRange for ObjectIndexKeyRange {
	const KIND: KeyKind = KeyKind::Index;

	fn start(&self) -> Option<EncodedKey> {
		let mut serializer = KeySerializer::with_capacity(10);
		serializer.extend_u8(Self::KIND as u8).extend_object_id(self.object);
		Some(serializer.to_encoded_key())
	}

	fn end(&self) -> Option<EncodedKey> {
		let mut serializer = KeySerializer::with_capacity(10);
		serializer.extend_u8(Self::KIND as u8).extend_object_id(self.object.prev());
		Some(serializer.to_encoded_key())
	}

	fn decode(range: &EncodedKeyRange) -> (Option<Self>, Option<Self>)
	where
		Self: Sized,
	{
		let start_key = match &range.start {
			Bound::Included(key) | Bound::Excluded(key) => Self::decode_key(key),
			Bound::Unbounded => None,
		};

		let end_key = match &range.end {
			Bound::Included(key) | Bound::Excluded(key) => Self::decode_key(key),
			Bound::Unbounded => None,
		};

		(start_key, end_key)
	}
}

impl IndexKey {
	pub fn encoded(object: impl Into<ObjectId>, index: impl Into<IndexId>) -> EncodedKey {
		Self {
			object: object.into(),
			index: index.into(),
		}
		.encode()
	}

	pub fn full_scan(object: impl Into<ObjectId>) -> EncodedKeyRange {
		let object = object.into();
		EncodedKeyRange::start_end(Some(Self::object_start(object)), Some(Self::object_end(object)))
	}

	pub fn object_start(object: impl Into<ObjectId>) -> EncodedKey {
		let object = object.into();
		let mut serializer = KeySerializer::with_capacity(10);
		serializer.extend_u8(Self::KIND as u8).extend_object_id(object);
		serializer.to_encoded_key()
	}

	pub fn object_end(object: impl Into<ObjectId>) -> EncodedKey {
		let object = object.into();
		let mut serializer = KeySerializer::with_capacity(10);
		serializer.extend_u8(Self::KIND as u8).extend_object_id(object.prev());
		serializer.to_encoded_key()
	}
}

#[cfg(test)]
pub mod tests {
	use super::{EncodableKey, IndexKey};
	use crate::interface::catalog::{id::IndexId, object::ObjectId};

	#[test]
	fn test_encode_decode() {
		let key = IndexKey {
			object: ObjectId::table(0xABCD),
			index: IndexId::primary(0x123456789ABCDEF0u64),
		};
		let encoded = key.encode();

		let expected: Vec<u8> = vec![
			0xF3, 0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x54, 0x32, 0xED, 0xCB, 0xA9, 0x87, 0x65, 0x43,
			0x21, 0x0F,
		];

		assert_eq!(encoded.as_slice(), expected);

		let key = IndexKey::decode(&encoded).unwrap();
		assert_eq!(key.object, 0xABCD);
		assert_eq!(key.index, 0x123456789ABCDEF0);
	}

	#[test]
	fn test_order_preserving() {
		let key1 = IndexKey {
			object: ObjectId::table(1),
			index: IndexId::primary(100),
		};
		let key2 = IndexKey {
			object: ObjectId::table(1),
			index: IndexId::primary(200),
		};
		let key3 = IndexKey {
			object: ObjectId::table(2),
			index: IndexId::primary(50),
		};

		let encoded1 = key1.encode();
		let encoded2 = key2.encode();
		let encoded3 = key3.encode();

		assert!(encoded3 < encoded2, "ordering not preserved");
		assert!(encoded2 < encoded1, "ordering not preserved");
	}
}