From b8fcd14ebe39441a5450eac71a4612f0ee34fb15 Mon Sep 17 00:00:00 2001
From: kjuulh <contact@kjuulh.io>
Date: Sat, 10 Sep 2022 01:19:29 +0200
Subject: [PATCH] Add base setup

---
 closers.go        |   7 +++
 component.go      |   7 +++
 default_logger.go |  15 ++++++
 go.mod            |   3 ++
 initer.go         |   7 +++
 lifetime.go       |  18 +++++++
 logger.go         |   6 +++
 manager.go        | 121 ++++++++++++++++++++++++++++++++++++++++++++++
 starter.go        |   7 +++
 9 files changed, 191 insertions(+)
 create mode 100644 closers.go
 create mode 100644 component.go
 create mode 100644 default_logger.go
 create mode 100644 go.mod
 create mode 100644 initer.go
 create mode 100644 lifetime.go
 create mode 100644 logger.go
 create mode 100644 manager.go
 create mode 100644 starter.go

diff --git a/closers.go b/closers.go
new file mode 100644
index 0000000..a9d84a3
--- /dev/null
+++ b/closers.go
@@ -0,0 +1,7 @@
+package curre
+
+import "context"
+
+type Closer interface {
+	Close(ctx context.Context) error
+}
diff --git a/component.go b/component.go
new file mode 100644
index 0000000..d7b4843
--- /dev/null
+++ b/component.go
@@ -0,0 +1,7 @@
+package curre
+
+type Component interface {
+	Initer
+	Starter
+	Closer
+}
diff --git a/default_logger.go b/default_logger.go
new file mode 100644
index 0000000..aacd3de
--- /dev/null
+++ b/default_logger.go
@@ -0,0 +1,15 @@
+package curre
+
+import "fmt"
+
+type DefaultLogger struct{}
+
+var _ Logger = &DefaultLogger{}
+
+func (dl *DefaultLogger) Info(msg string, args ...any) {
+	fmt.Printf(msg, args...)
+}
+
+func (dl *DefaultLogger) Error(msg string, args ...any) {
+	fmt.Printf(msg, args...)
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..246e4d6
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module git.front.kjuulh.io/kjuulh/curre
+
+go 1.19
diff --git a/initer.go b/initer.go
new file mode 100644
index 0000000..6fac353
--- /dev/null
+++ b/initer.go
@@ -0,0 +1,7 @@
+package curre
+
+import "context"
+
+type Initer interface {
+	Init(ctx context.Context) error
+}
diff --git a/lifetime.go b/lifetime.go
new file mode 100644
index 0000000..c8082b5
--- /dev/null
+++ b/lifetime.go
@@ -0,0 +1,18 @@
+package curre
+
+import (
+	"os"
+	"os/signal"
+	"syscall"
+)
+
+type Lifetime func() int
+
+func ConsoleLifetime() int {
+	signals := make(chan os.Signal, 1)
+	signal.Notify(signals, syscall.SIGINT, syscall.SIGTERM)
+
+	<-signals
+
+	return OK
+}
diff --git a/logger.go b/logger.go
new file mode 100644
index 0000000..fd4761b
--- /dev/null
+++ b/logger.go
@@ -0,0 +1,6 @@
+package curre
+
+type Logger interface {
+	Info(msg string, args ...any)
+	Error(msg string, args ...any)
+}
diff --git a/manager.go b/manager.go
new file mode 100644
index 0000000..a217a80
--- /dev/null
+++ b/manager.go
@@ -0,0 +1,121 @@
+package curre
+
+import (
+	"context"
+	"sync"
+)
+
+const (
+	OK       = 0
+	Internal = 1
+)
+
+type Manager struct {
+	components    []Component
+	logger        Logger
+	startStopLock sync.Mutex
+	started       bool
+	exitChan      chan int
+	exitCode      int
+	lifetime      Lifetime
+}
+
+func NewManager() *Manager {
+	return &Manager{
+		logger: &DefaultLogger{}, exitChan: make(chan int, 1),
+		exitCode: OK,
+	}
+}
+
+func (m *Manager) Register(components ...Component) *Manager {
+	if m.started {
+		panic("cannot register to a started manager")
+	}
+
+	m.components = append(m.components, components...)
+
+	return m
+}
+
+func (m *Manager) Init(ctx context.Context) error {
+	if m.started {
+		panic("cannot reinit a started manager")
+	}
+
+	for _, c := range m.components {
+		err := c.Init(ctx)
+		if err != nil {
+			return err
+		}
+
+		m.logger.Info("Manager: Init: %T", c)
+	}
+
+	return nil
+}
+
+func (m *Manager) Start(ctx context.Context) error {
+	for _, c := range m.components {
+		go m.startComponent(ctx, c)
+	}
+
+	return nil
+}
+
+func (m *Manager) startComponent(ctx context.Context, component Component) {
+	defer func() {
+		err := recover()
+		if err != nil {
+			m.logger.Error("Panic occurred in component: %T, error: %s", component, err)
+		}
+
+		m.exitChan <- Internal
+	}()
+
+	m.logger.Info("Starting %T", component)
+	err := component.Start(ctx)
+	if err != nil {
+		m.logger.Error("Component: %T encountered an error: ", component, err)
+		m.exitChan <- Internal
+		return
+	}
+
+	m.logger.Info("Component %T, done running", component)
+
+}
+
+func (m *Manager) initLifetime() {
+	go func() {
+		exitCode := m.lifetime()
+		m.logger.Info("Exit signal received: %d", exitCode)
+		m.exitChan <- exitCode
+	}()
+}
+
+func (m *Manager) Wait(ctx context.Context) error {
+	exitCode := <-m.exitChan
+	m.exitCode = exitCode
+	return nil
+}
+
+func (m *Manager) Shutdown(ctx context.Context) error {
+	shutdownChan := make(chan struct{}, 1)
+	closers := m.getClosers(ctx)
+
+	go func(ctx context.Context) {
+		for _, c := range closers {
+			c.Close(ctx)
+		}
+
+		shutdownChan <- struct{}{}
+	}(ctx)
+
+	<-shutdownChan
+	m.logger.Info("Shutting down of components complete")
+
+	return nil
+}
+
+func (m *Manager) getClosers(ctx context.Context) []Component {
+	return m.components
+}
diff --git a/starter.go b/starter.go
new file mode 100644
index 0000000..5083701
--- /dev/null
+++ b/starter.go
@@ -0,0 +1,7 @@
+package curre
+
+import "context"
+
+type Starter interface {
+	Start(ctx context.Context) error
+}