From 366373b886e49d250d1a2c1e8edcf8ac47d56b5a Mon Sep 17 00:00:00 2001
From: Andrew Sisley <a.j.sisley@hotmail.com>
Date: Mon, 28 Oct 2024 13:51:53 -0400
Subject: [PATCH] WIP - Implement branchable collections

---
 internal/core/crdt/collection.go   | 69 ++++++++++++++++++++++++++++++
 internal/merkle/crdt/collection.go | 60 ++++++++++++++++++++++++++
 2 files changed, 129 insertions(+)
 create mode 100644 internal/core/crdt/collection.go
 create mode 100644 internal/merkle/crdt/collection.go

diff --git a/internal/core/crdt/collection.go b/internal/core/crdt/collection.go
new file mode 100644
index 0000000000..6493b8e526
--- /dev/null
+++ b/internal/core/crdt/collection.go
@@ -0,0 +1,69 @@
+// Copyright 2024 Democratized Data Foundation
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package crdt
+
+import (
+	"context"
+
+	"github.com/sourcenetwork/defradb/datastore"
+	"github.com/sourcenetwork/defradb/internal/core"
+)
+
+type Collection struct {
+	store datastore.DSReaderWriter
+	// schemaVersionKey is the schema version datastore key at the time of commit.
+	//
+	// It can be used to identify the collection datastructure state at the time of commit.
+	schemaVersionKey core.CollectionSchemaVersionKey
+}
+
+var _ core.ReplicatedData = (*Collection)(nil)
+
+func NewCollection(store datastore.DSReaderWriter, schemaVersionKey core.CollectionSchemaVersionKey) *Collection {
+	return &Collection{
+		store:            store,
+		schemaVersionKey: schemaVersionKey,
+	}
+}
+
+func (c *Collection) Merge(ctx context.Context, other core.Delta) error {
+	panic("todo")
+}
+
+func (c *Collection) Append() *CollectionDelta {
+	return &CollectionDelta{
+		SchemaVersionID: c.schemaVersionKey.SchemaVersionID,
+	}
+}
+
+type CollectionDelta struct {
+	Priority uint64
+	// todo: This is temporary pending a global collection id (link to ticket)
+	SchemaVersionID string
+}
+
+var _ core.Delta = (*CollectionDelta)(nil)
+
+func (delta *CollectionDelta) IPLDSchemaBytes() []byte {
+	return []byte(`
+	type CollectionDelta struct {
+		priority  		Int
+		schemaVersionID String
+	}`)
+}
+
+func (d *CollectionDelta) GetPriority() uint64 {
+	panic("todo")
+}
+
+func (d *CollectionDelta) SetPriority(uint64) {
+	panic("todo")
+}
diff --git a/internal/merkle/crdt/collection.go b/internal/merkle/crdt/collection.go
new file mode 100644
index 0000000000..c913245cae
--- /dev/null
+++ b/internal/merkle/crdt/collection.go
@@ -0,0 +1,60 @@
+// Copyright 2024 Democratized Data Foundation
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package merklecrdt
+
+import (
+	"context"
+
+	cidlink "github.com/ipld/go-ipld-prime/linking/cid"
+	"github.com/sourcenetwork/defradb/client"
+	"github.com/sourcenetwork/defradb/internal/core"
+	coreblock "github.com/sourcenetwork/defradb/internal/core/block"
+	"github.com/sourcenetwork/defradb/internal/core/crdt"
+	"github.com/sourcenetwork/defradb/internal/merkle/clock"
+)
+
+type MerkleCollection struct {
+	clock *clock.MerkleClock
+	reg   *crdt.Collection
+}
+
+var _ MerkleCRDT = (*MerkleCollection)(nil)
+
+func NewMerkleCollection(
+	store Stores,
+	schemaVersionKey core.CollectionSchemaVersionKey,
+) *MerkleCollection {
+	register := crdt.NewCollection(store.Datastore(), schemaVersionKey)
+
+	// todo - you can interface HeadStoreKey so that it has a `WithCid` func then it should hopefuly all be good
+	//clk := clock.NewMerkleClock(store.Headstore(), store.Blockstore(), store.Encstore(), key.ToHeadStoreKey(), register)
+
+	return &MerkleCollection{
+		//clock: clk,
+		reg: register,
+	}
+}
+
+func (m *MerkleCollection) Clock() *clock.MerkleClock {
+	return m.clock
+}
+
+// Save the value of the  Counter to the DAG.
+func (m *MerkleCollection) Save(ctx context.Context, data any) (cidlink.Link, []byte, error) {
+	links, ok := data.([]coreblock.DAGLink)
+	if !ok {
+		return cidlink.Link{}, nil, NewErrUnexpectedValueType(client.COMPOSITE, []coreblock.DAGLink{}, data)
+	}
+
+	delta := m.reg.Append()
+
+	return m.clock.AddDelta(ctx, delta, links...)
+}