From b2c10eeb403337da83981a6d16e4ff69ddd3c5c5 Mon Sep 17 00:00:00 2001
From: Googol Lee <i@googol.im>
Date: Tue, 19 Sep 2023 13:17:03 +0200
Subject: [PATCH] Update module

---
 module.go | 62 +++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 44 insertions(+), 18 deletions(-)

diff --git a/module.go b/module.go
index a0d69ba..5b629ff 100644
--- a/module.go
+++ b/module.go
@@ -2,44 +2,70 @@ package espresso
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"reflect"
 )
 
-type moduleName string
+var ErrModuleDependError = errors.New("depend error")
 
-type Module[T any] struct {
-	name moduleName
+type Module interface {
+	Name() moduleName
+	Check(context.Context) error
 }
 
-func DefineModule[T any]() Module[T] {
-	var t T
-	typ := reflect.TypeOf(t)
-	if typ.Kind() == reflect.Ptr {
-		panic("T should be a type, not a pointer.")
-	}
+type ModuleImplementer interface {
+	Check(context.Context) error
+}
 
-	name := fmt.Sprintf("%T", t)
+type moduleName string
+
+type ModuleType[T ModuleImplementer] struct {
+	name    moduleName
+	depends []Module
+}
 
-	return Module[T]{
-		name: moduleName(name),
+func DefineModule[T ModuleImplementer](depends ...Module) *ModuleType[T] {
+	var t T
+	name := reflect.TypeOf(t).Name()
+	return &ModuleType[T]{
+		name:    moduleName(name),
+		depends: depends,
 	}
 }
 
-func (m Module[T]) With(ctx context.Context, moduleInstance *T) context.Context {
-	return context.WithValue(ctx, m.name, moduleInstance)
+func (m ModuleType[T]) Name() moduleName {
+	return m.name
 }
 
-func (m Module[T]) Value(ctx context.Context) *T {
+func (m ModuleType[T]) Value(ctx context.Context) T {
+	var n T
 	v := ctx.Value(m.name)
 	if v == nil {
-		return nil
+		return n
 	}
 
-	ret, ok := v.(*T)
+	ret, ok := v.(T)
 	if !ok {
-		return nil
+		return n
 	}
 
 	return ret
 }
+
+func (m *ModuleType[T]) Check(ctx context.Context) error {
+	var errs []error
+	for _, module := range m.depends {
+		if err := module.Check(ctx); err != nil {
+			errs = append(errs, fmt.Errorf("module %s: %w", module.Name(), err))
+		}
+	}
+
+	if len(errs) != 0 {
+		errs = append(errs, fmt.Errorf("module %s: %w", m.Name(), ErrModuleDependError))
+	} else if err := m.Check(ctx); err != nil {
+		errs = append(errs, fmt.Errorf("module %s: %w", m.Name(), err))
+	}
+
+	return errors.Join(errs...)
+}