From 242029f2e5014f350af2b9e2e21657acb70ff4f9 Mon Sep 17 00:00:00 2001
From: max <max@mpatterson.xyz>
Date: Tue, 4 Apr 2023 14:37:23 -0500
Subject: [PATCH] Initial task scheduler implementation

---
 app/app.go      |  7 ++---
 app/schedule.go | 69 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+), 3 deletions(-)
 create mode 100644 app/schedule.go

diff --git a/app/app.go b/app/app.go
index df1aef2..53db2ec 100644
--- a/app/app.go
+++ b/app/app.go
@@ -8,7 +8,8 @@ import (
 
 // App contains and supplies available configurations and connections
 type App struct {
-	Config config.Configuration // Configuration file
-	Db     *sql.DB              // Database connection
-	Res    *embed.FS            // Resources from the embedded filesystem
+	Config         config.Configuration // Configuration file
+	Db             *sql.DB              // Database connection
+	Res            *embed.FS            // Resources from the embedded filesystem
+	ScheduledTasks Scheduled            // Scheduled contains a struct of all scheduled functions
 }
diff --git a/app/schedule.go b/app/schedule.go
new file mode 100644
index 0000000..3ff8d86
--- /dev/null
+++ b/app/schedule.go
@@ -0,0 +1,69 @@
+package app
+
+import "time"
+
+type Scheduled struct {
+	EveryReboot []func(app *App)
+	EverySecond []func(app *App)
+	EveryMinute []func(app *App)
+	EveryHour   []func(app *App)
+	EveryDay    []func(app *App)
+	EveryWeek   []func(app *App)
+	EveryMonth  []func(app *App)
+	EveryYear   []func(app *App)
+}
+
+type Task struct {
+	Interval time.Duration
+	Funcs    []func(app *App)
+}
+
+func RunScheduledTasks(app *App, poolSize int, stop <-chan struct{}) {
+	// Run every time the server starts
+	for _, f := range app.ScheduledTasks.EveryReboot {
+		f(app)
+	}
+
+	tasks := []Task{
+		{Interval: time.Second, Funcs: app.ScheduledTasks.EverySecond},
+		{Interval: time.Minute, Funcs: app.ScheduledTasks.EveryMinute},
+		{Interval: time.Hour, Funcs: app.ScheduledTasks.EveryHour},
+		{Interval: 24 * time.Hour, Funcs: app.ScheduledTasks.EveryDay},
+		{Interval: 7 * 24 * time.Hour, Funcs: app.ScheduledTasks.EveryWeek},
+		{Interval: 30 * 24 * time.Hour, Funcs: app.ScheduledTasks.EveryMonth},
+		{Interval: 365 * 24 * time.Hour, Funcs: app.ScheduledTasks.EveryYear},
+	}
+
+	// Set up task runners
+	runners := make([]chan bool, len(tasks))
+	for i, task := range tasks {
+		runner := make(chan bool, poolSize)
+		runners[i] = runner
+		go func(task Task, runner chan bool) {
+			ticker := time.NewTicker(task.Interval)
+			defer ticker.Stop()
+			for {
+				select {
+				case <-ticker.C:
+					for _, f := range task.Funcs {
+						runner <- true
+						go func(f func(app *App)) {
+							defer func() { <-runner }()
+							f(app)
+						}(f)
+					}
+				case <-stop:
+					return
+				}
+			}
+		}(task, runner)
+	}
+
+	// Wait for termination
+	for _, runner := range runners {
+		for i := 0; i < cap(runner); i++ {
+			runner <- false
+		}
+		close(runner)
+	}
+}