From 06776329bd2e347f386a0f823a74af4ea381d758 Mon Sep 17 00:00:00 2001
From: Robin <rtmbaertschi007@gmail.com>
Date: Wed, 23 Oct 2024 21:59:11 +0200
Subject: [PATCH] Begin dependency injection

---
 diego.go      | 43 +++++++++++++++++++++++++++++++++++++++++++
 diego_test.go | 22 ++++++++++++++++++++++
 go.mod        |  3 +++
 3 files changed, 68 insertions(+)
 create mode 100644 diego.go
 create mode 100644 diego_test.go
 create mode 100644 go.mod

diff --git a/diego.go b/diego.go
new file mode 100644
index 0000000..6c18486
--- /dev/null
+++ b/diego.go
@@ -0,0 +1,43 @@
+package diego
+
+import (
+	"fmt"
+	"net/http"
+)
+
+type Router struct {
+	mux http.ServeMux
+}
+
+type InjectionContext struct{}
+
+type InjectionFunction[T any] func(InjectionContext) T
+
+type InjectionToken[T any] struct {
+	Name          string
+	InjectionFunc InjectionFunction[T]
+}
+
+var injectionTokens map[string]any = make(map[string]any)
+
+func Inject[T any](token InjectionToken[T]) T {
+	var value = injectionTokens[token.Name]
+
+	if value == nil {
+		value = token.InjectionFunc(InjectionContext{})
+		injectionTokens[token.Name] = value
+	}
+
+	var injection, ok = value.(T)
+
+	if !ok {
+		panic(fmt.Sprintf("FATAL ERROR: Tried to inject a value with the wrong type, expected = %T, got = %T", *new(T), value))
+	}
+	return injection
+
+}
+
+func Test() {}
+
+func (r *Router) Start() {
+}
diff --git a/diego_test.go b/diego_test.go
new file mode 100644
index 0000000..5877ba0
--- /dev/null
+++ b/diego_test.go
@@ -0,0 +1,22 @@
+package diego
+
+import "testing"
+
+const testString = "hello"
+
+func GetBasicString(ctx InjectionContext) string {
+	return testString
+}
+
+var BasicStringToken InjectionToken[string] = InjectionToken[string]{
+	"BASIC_STRING",
+	GetBasicString,
+}
+
+func TestDependencyInjection(t *testing.T) {
+	value := Inject(BasicStringToken)
+
+	if value != testString {
+		t.Errorf("Could not inject basic string token, expected = %s(%T), got = %s(%T)", testString, testString, value, value)
+	}
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..e69af28
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module robaertschi.xyz/diego
+
+go 1.23.2