From c1c6effc15cf5597c72a25c0eae93928a5b9f569 Mon Sep 17 00:00:00 2001
From: Erik Kristensen <erik@erikkristensen.com>
Date: Sun, 14 Apr 2024 16:15:04 -0600
Subject: [PATCH] feat: generate property documentation for resources

---
 pkg/docs/generate.go      | 75 +++++++++++++++++++++++++++++++++++++++
 pkg/docs/generate_test.go | 57 +++++++++++++++++++++++++++++
 pkg/registry/registry.go  |  6 ++++
 3 files changed, 138 insertions(+)
 create mode 100644 pkg/docs/generate.go
 create mode 100644 pkg/docs/generate_test.go

diff --git a/pkg/docs/generate.go b/pkg/docs/generate.go
new file mode 100644
index 0000000..ef5ac57
--- /dev/null
+++ b/pkg/docs/generate.go
@@ -0,0 +1,75 @@
+package docs
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+)
+
+func GeneratePropertiesMap(data interface{}) map[string]string {
+	properties := map[string]string{}
+
+	v := reflect.ValueOf(data)
+	if v.Kind() == reflect.Ptr {
+		v = v.Elem()
+	}
+	t := v.Type()
+
+	for i := 0; i < t.NumField(); i++ {
+		field := t.Field(i)
+
+		if !field.IsExported() {
+			continue
+		}
+
+		propertyTag := field.Tag.Get("property")
+		options := strings.Split(propertyTag, ",")
+		name := field.Name
+		prefix := ""
+
+		if options[0] == "-" {
+			continue
+		}
+
+		for _, option := range options {
+			parts := strings.Split(option, "=")
+			if len(parts) != 2 {
+				continue
+			}
+			switch parts[0] {
+			case "name":
+				name = parts[1]
+			case "prefix":
+				prefix = parts[1]
+			}
+		}
+
+		if prefix != "" && name != "Tags" {
+			name = fmt.Sprintf("%s:%s", prefix, name)
+		}
+
+		descriptionTag := field.Tag.Get("description")
+
+		if name == "Tags" {
+			originalName := name
+			name = "tag:<key>:"
+			tagPrefix := "tag:"
+			if prefix != "" {
+				tagPrefix = fmt.Sprintf("tag:%s:", prefix)
+			}
+
+			descriptionTag = fmt.Sprintf(
+				"This resource has tags with property `%s`. These are key/value pairs that are\n\t"+
+					"added as their own property with the prefix of `%s` (e.g. [%sexample: \"value\"]) ",
+				originalName, tagPrefix, tagPrefix)
+
+			if prefix != "" {
+				name = fmt.Sprintf("tag:%s:<key>:", prefix)
+			}
+		}
+
+		properties[name] = fmt.Sprintf("%s", descriptionTag)
+	}
+
+	return properties
+}
diff --git a/pkg/docs/generate_test.go b/pkg/docs/generate_test.go
new file mode 100644
index 0000000..e58c0f7
--- /dev/null
+++ b/pkg/docs/generate_test.go
@@ -0,0 +1,57 @@
+package docs
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestGenerateProperties(t *testing.T) {
+	type TestResource1 struct {
+		Name   string            `description:"The name of the resource"`
+		Region *string           `description:"The region in which the resource resides"`
+		VpcID  string            `description:"The VPC ID of the resource" property:"prefix=vpc"`
+		Tags   map[string]string `description:"The tags associated with the resource"`
+	}
+
+	type TestResource2 struct {
+		Name   string            `description:"The name of the resource"`
+		Region *string           `description:"The region in which the resource resides"`
+		Tags   map[string]string `description:"The tags associated with the resource" property:"prefix=ee"`
+	}
+
+	cases := []struct {
+		name string
+		in   interface{}
+		want map[string]string
+	}{
+		{
+			name: "TestResource1",
+			in:   TestResource1{},
+			want: map[string]string{
+				"Name":      "The name of the resource",
+				"Region":    "The region in which the resource resides",
+				"vpc:VpcID": "The VPC ID of the resource",
+				"tag:<key>:": "This resource has tags with property `Tags`. These are key/value pairs that are\n\t" +
+					"added as their own property with the prefix of `tag:` (e.g. [tag:example: \"value\"]) ",
+			},
+		},
+		{
+			name: "TestResource2",
+			in:   TestResource2{},
+			want: map[string]string{
+				"Name":   "The name of the resource",
+				"Region": "The region in which the resource resides",
+				"tag:ee:<key>:": "This resource has tags with property `Tags`. These are key/value pairs that are\n\t" +
+					"added as their own property with the prefix of `tag:ee:" +
+					"` (e.g. [tag:ee:example: \"value\"]) ",
+			},
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			have := GeneratePropertiesMap(c.in)
+			assert.Equal(t, c.want, have)
+		})
+	}
+}
diff --git a/pkg/registry/registry.go b/pkg/registry/registry.go
index 3f9159f..0236812 100644
--- a/pkg/registry/registry.go
+++ b/pkg/registry/registry.go
@@ -48,6 +48,12 @@ type Registration struct {
 	// different levels, whereas AWS has simply Account level.
 	Scope Scope
 
+	// Resource is the resource type that the lister is going to list. This is a struct that implements the Resource
+	// interface. This is primarily used to generate documentation by parsing the structs properties and generating
+	// markdown documentation.
+	// Note: it is a interface{} because we are going to inspect it, we do not need to actually call any methods on it.
+	Resource interface{}
+
 	// Lister is the lister for the resource type, it is a struct with a method called List that returns a slice
 	// of resources. The lister is responsible for filtering out any resources that should not be deleted because they
 	// are ineligible for deletion. For example, built in resources that cannot be deleted.