Handle schema change in node

action.go

@@ -5,3 +5,42 @@ type Action func(*Checkpoint)
 
 // ActionDefault ...
 func ActionDefault(cp *Checkpoint) {}
+
+// ActionPostSet ...
+func ActionPostSet(cp *Checkpoint) {
+	cp.SetID("$0", cp.Get("0_sets", "$0", "name").(string))
+}
+
+// ActionPostAttr ...
+func ActionPostAttr(cp *Checkpoint) {
+	set := cp.Get("0_sets", "$0", "set").(string)
+	name := cp.Get("0_sets", "$0", "name").(string)
+
+	cp.SetID("$0", set+"_"+name)
+}
+
+// ActionPostRel ...
+func ActionPostRel(cp *Checkpoint) {
+	set := cp.Get("0_sets", "$0", "set").(string)
+	name := cp.Get("0_sets", "$0", "from-name").(string)
+
+	cp.SetID("$0", set+"_"+name)
+}
+
+// ActionPatchSet ...
+func ActionPatchSet(cp *Checkpoint) {}
+
+// ActionPatchAttr ...
+func ActionPatchAttr(cp *Checkpoint) {}
+
+// ActionPatchRel ...
+func ActionPatchRel(cp *Checkpoint) {}
+
+// ActionDeleteSet ...
+func ActionDeleteSet(cp *Checkpoint) {}
+
+// ActionDeleteAttr ...
+func ActionDeleteAttr(cp *Checkpoint) {}
+
+// ActionDeleteRel ...
+func ActionDeleteRel(cp *Checkpoint) {}

checkpoint.go

@@ -2,6 +2,8 @@ package karigo
 
 import (
 	"errors"
+	"fmt"
+	"strconv"
 
 	"github.com/mfcochauxlaberge/karigo/query"
 
@@ -10,13 +12,12 @@ import (
 
 // Checkpoint ...
 type Checkpoint struct {
-	Res jsonapi.Resource
-	Inc map[string]jsonapi.Resource
-
-	tx   query.Tx
-	node *Node
+	tx     query.Tx
+	schema *jsonapi.Schema
+	node   *Node
 
 	ops []query.Op
+	ids map[string]string
 
 	err error
 }
@@ -78,6 +79,72 @@ func (c *Checkpoint) Fail(err error) {
 	c.err = err
 }
 
+// Val finds and returns the value the given field is set to in the current ops.
+//
+// The second return argument reports whether a set operation was found. Other
+// operations (add, subtract, insert, etc) are ignored since a fix value cannot
+// be calculated.
+func (c *Checkpoint) Val(set, id, field string) (interface{}, bool) {
+	for _, op := range c.ops {
+		if op.Key.Set == set && op.Key.ID == id && op.Key.Field == field {
+			return op.Value, true
+		}
+	}
+
+	return nil, false
+}
+
+// NumChange finds and returns the change applied to the given field in the
+// current ops.
+//
+// A change is represented by OpAdd or OpSubtract. It is assumed that the field
+// is of numerical type (int, int8, uint, etc).
+func (c *Checkpoint) NumChange(set, id, field string) int {
+	for _, op := range c.ops {
+		if op.Key.Set == set && op.Key.ID == id && op.Key.Field == field {
+			i, _ := strconv.ParseInt(fmt.Sprintf("%d", op.Value), 10, 64)
+			return int(i)
+		}
+	}
+
+	return 0
+}
+
+// RelsChange finds and returns the inserted and removed IDs for the given
+// relationship.
+//
+// The first return argument is the added IDs, and the second one is the removed
+// IDs.
+//
+// A change is represented by OpInset or OpRemove. It is assumed that the field
+// is of type []byte or []string for to-many relationships.
+func (c *Checkpoint) RelsChange(set, id, field string) ([]string, []string) {
+	var insertions, removals []string
+
+	for _, op := range c.ops {
+		if op.Key.Set == set && op.Key.ID == id && op.Key.Field == field {
+			if op.Op == query.OpInsert {
+				insertions = op.Value.([]string)
+			} else {
+				removals = op.Value.([]string)
+			}
+		}
+	}
+
+	return insertions, removals
+}
+
+// SetID ...
+func (c *Checkpoint) SetID(placeholder, id string) interface{} {
+	if c.ids == nil {
+		c.ids = map[string]string{}
+	}
+
+	c.ids[placeholder] = id
+
+	return nil
+}
+
 // commit ...
 func (c *Checkpoint) commit() error {
 	return c.tx.Commit()

node.go

@@ -69,7 +69,17 @@ func (n *Node) Handle(r *Request) *jsonapi.Document {
 	}
 
 	if n.funcs == nil {
-		n.funcs = map[string]Action{}
+		n.funcs = map[string]Action{
+			"POST 0_sets":    ActionPostSet,
+			"POST 0_attrs":   ActionPostSet,
+			"POST 0_rels":    ActionPostSet,
+			"PATCH 0_sets":   ActionPatchSet,
+			"PATCH 0_attrs":  ActionPatchSet,
+			"PATCH 0_rels":   ActionPatchSet,
+			"DELETE 0_sets":  ActionDeleteSet,
+			"DELETE 0_attrs": ActionDeleteSet,
+			"DELETE 0_rels":  ActionDeleteSet,
+		}
 	}
 
 	var (
@@ -211,33 +221,8 @@ func (n *Node) Handle(r *Request) *jsonapi.Document {
 		if res.GetID() == "" {
 			res.SetID(uuid.New().String()[:8])
 		}
-		// TODO Do not hardcode the following conditions. It can
-		// be handled in a much better way.
-		switch res.GetType().Name {
-		case "0_sets":
-			res.SetID(res.Get("name").(string))
-			ops = query.NewOpCreateSet(res.GetID())
-		case "0_attrs":
-			ops = query.NewOpCreateAttr(
-				res.GetToOne("set"),
-				res.Get("name").(string),
-				res.Get("type").(string),
-				res.Get("null").(bool),
-			)
-			res.SetID(ops[0].Value.(string))
-		case "0_rels":
-			ops = query.NewOpCreateRel(
-				res.GetToOne("from-set"),
-				res.Get("from-name").(string),
-				res.GetToOne("to-set"),
-				res.Get("to-name").(string),
-				res.Get("to-one").(bool),
-				res.Get("from-one").(bool),
-			)
-			res.SetID(ops[0].Value.(string))
-		default:
-			ops = query.NewOpCreateRes(res)
-		}
+
+		ops = query.NewOpCreateRes(res)
 
 		found, _ := cp.tx.Resource(query.Res{
 			Set:    res.GetType().Name,
@@ -283,12 +268,14 @@ func (n *Node) Handle(r *Request) *jsonapi.Document {
 
 	cp.Apply(ops)
 
+	// Execute
+	execute(cp)
+
 	if r.isSchemaChange() {
-		// Handle schema change
-		handleSchemaChange(n.schema, r, cp)
-	} else {
-		// Execute
-		execute(cp)
+		err = updateSchema(n.schema, cp.tx)
+		if err != nil {
+			panic(fmt.Errorf("could not update schema: %s", err))
+		}
 	}
 
 	for _, op := range cp.ops {