From a3fc4c89c076a23d65845637d3fc860abac8f050 Mon Sep 17 00:00:00 2001
From: Matias Insaurralde <matias@insaurral.de>
Date: Mon, 7 May 2018 01:13:14 -0400
Subject: [PATCH] Initial work on #6

---
 generator/generator.go | 100 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 generator/generator.go

diff --git a/generator/generator.go b/generator/generator.go
new file mode 100644
index 0000000..4f7793a
--- /dev/null
+++ b/generator/generator.go
@@ -0,0 +1,100 @@
+package generator
+
+import (
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"strings"
+
+	"github.com/sirupsen/logrus"
+)
+
+var (
+	log = logrus.New()
+)
+
+// Generator generates code for interoperability between Go and .NET.
+type Generator struct {
+	Input []*Input
+}
+
+// Input is a data structure used for every parsed file, contains the AST, path information and annotations.
+type Input struct {
+	fileset *token.FileSet
+	astFile *ast.File
+	path    string
+
+	annotations []*DelegateAnnotation
+}
+
+// Parse builds the AST and extracts information useful for the generation step.
+func (i *Input) Parse() (err error) {
+	log.WithFields(logrus.Fields{
+		"file": i.path,
+	}).Info("Parsing file")
+
+	i.fileset = token.NewFileSet()
+	i.astFile, err = parser.ParseFile(i.fileset, i.path, nil, parser.ParseComments)
+	if err != nil {
+		return err
+	}
+	i.annotations = make([]*DelegateAnnotation, 0)
+
+	for _, decl := range i.astFile.Decls {
+		function, ok := decl.(*ast.FuncDecl)
+		if !ok {
+			continue
+		}
+		comments := function.Doc.List
+		if len(comments) == 0 {
+			continue
+		}
+		for _, v := range comments {
+			if strings.HasPrefix(v.Text, delegatePrefix) {
+				annotation := parseAnnotation(v.Text)
+				log.WithFields(logrus.Fields{
+					"annotation": annotation,
+				}).Debug("Found annotation")
+				i.annotations = append(i.annotations, &annotation)
+			}
+		}
+	}
+	log.Debugf("Finished checking %s, found %d annotations", i.path, len(i.annotations))
+	return nil
+}
+
+// New initializes a generator.
+func New(input []string) *Generator {
+	g := Generator{
+		Input: make([]*Input, 0),
+	}
+	for _, path := range input {
+		i := &Input{path: path}
+		g.Input = append(g.Input, i)
+	}
+	return &g
+}
+
+// Verbose modifies the verbosity level.
+func (g *Generator) Verbose(mode bool) *Generator {
+	if mode {
+		log.Level = logrus.DebugLevel
+	}
+	return g
+}
+
+// Parse iterates through every input file, calling the proper method.
+func (g *Generator) Parse() (err error) {
+	for _, input := range g.Input {
+		err = input.Parse()
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Generate performs the code generation step.
+func (g *Generator) Generate() (err error) {
+	return nil
+}