feat: Graph to SDL conversion (#2)

Author: kevinmichaelchen

internal/cli/cli_pick.go

@@ -31,11 +31,15 @@ func fnPick(cmd *cobra.Command, args []string) {
 	// The most crucial step is to map out the AST.
 	// The AST object itself is clunky and nested.
 	// We need something flatter and more ergonomic: like a couple of maps!
-	g := buildSchemaGraph(astDoc)
+	g := buildPrunedGraph(astDoc)
 
 	// Build a visual diagram of the new SDL
 	file, _ := os.Create("./simple.gv")
 	_ = draw.DOT(g, file)
 
-	// TODO convert the GRAPH to an SDL
+	// Convert the GRAPH back to an SDL
+	newSDL := convertGraphToSDL(g)
+
+	// Print the new SDL to file
+	printSDL(newSDL)
 }

internal/cli/graph.go

@@ -52,7 +52,7 @@ func VertexHash(v Vertex) string {
 //
 // This will provide constant-time access to a map of type names to their
 // definitions, as well as definitions to their dependencies (other types).
-func buildSchemaGraph(doc *ast.Document) graph.Graph[string, Vertex] {
+func buildPrunedGraph(doc *ast.Document) graph.Graph[string, Vertex] {
 	g := graph.New(VertexHash)
 
 	// Load the important definitions:
@@ -102,7 +102,7 @@ func buildEdges(g graph.Graph[string, Vertex], doc *ast.Document) {
 		}
 
 		switch v.Node.GetKind() {
-		// TODO support input objects, input values, interfaces, and unions
+		// TODO support input objects, input values, interfaces, and unions... otherwise we're missing things like AircraftsBoolExp
 		case kinds.ObjectDefinition:
 			obj := v.Node.(*ast.ObjectDefinition)
 			fields := obj.Fields

internal/cli/graph_to_sdl.go

@@ -0,0 +1,32 @@
+package cli
+
+import (
+	"github.com/charmbracelet/log"
+	"github.com/dominikbraun/graph"
+	"github.com/graphql-go/graphql/language/ast"
+	"github.com/graphql-go/graphql/language/kinds"
+)
+
+func convertGraphToSDL(g graph.Graph[string, Vertex]) *ast.Document {
+	out := &ast.Document{
+		Kind:        kinds.Document,
+		Loc:         nil,
+		Definitions: nil,
+	}
+
+	var defs []ast.Node
+
+	adj, err := g.AdjacencyMap()
+	if err != nil {
+		log.Fatal("unable to retrieve AdjacencyMap", "err", err)
+	}
+
+	for defName := range adj {
+		def := must(g.Vertex(defName))
+		defs = append(defs, def.Node)
+	}
+
+	out.Definitions = defs
+
+	return out
+}

internal/cli/print.go

@@ -0,0 +1,29 @@
+package cli
+
+import (
+	"bufio"
+	"github.com/charmbracelet/log"
+	"github.com/graphql-go/graphql/language/ast"
+	"github.com/graphql-go/graphql/language/printer"
+	"os"
+)
+
+func printSDL(doc *ast.Document) {
+	sdl := printer.Print(doc)
+
+	// Create a new file where we'll write the new SDL
+	// TODO make configurable
+	f, err := os.Create("output.sdl.graphqls")
+	if err != nil {
+		log.Fatal("unable to create new SDL file for writing", "err", err)
+	}
+
+	defer f.Close()
+
+	w := bufio.NewWriter(f)
+
+	_, err = w.WriteString(sdl.(string))
+	if err != nil {
+		log.Fatal("unable to produce new SDL file", "err", err)
+	}
+}