From 6aeb0a179567b944ecf81e1bbfdd474c1ee171f1 Mon Sep 17 00:00:00 2001
From: Adam Fowler <adamfowler71@gmail.com>
Date: Sat, 21 Dec 2024 07:48:59 +0000
Subject: [PATCH] Latest scheduling should update based off the latest of
 nextScheduledData or now (#44)

---
 Sources/Jobs/Scheduler/JobSchedule.swift | 18 +++++---
 Tests/JobsTests/JobSchedulerTests.swift  | 57 +++++++++++++++++++++---
 2 files changed, 63 insertions(+), 12 deletions(-)

diff --git a/Sources/Jobs/Scheduler/JobSchedule.swift b/Sources/Jobs/Scheduler/JobSchedule.swift
index bf25859..12c2995 100644
--- a/Sources/Jobs/Scheduler/JobSchedule.swift
+++ b/Sources/Jobs/Scheduler/JobSchedule.swift
@@ -101,9 +101,9 @@ public struct JobSchedule: MutableCollection, Sendable {
     mutating func updateNextScheduledDate(jobIndex: Int) {
         let dateFrom: Date =
             switch self.self[jobIndex].accuracy {
-            case .latest: .now
+            case .latest: Swift.max(.now, self[jobIndex].nextScheduledDate)
             case .all: self[jobIndex].nextScheduledDate
-            default: .now
+            default: Swift.max(.now, self[jobIndex].nextScheduledDate)
             }
         if let nextScheduledDate = self[jobIndex].schedule.nextDate(after: dateFrom) {
             self[jobIndex].nextScheduledDate = nextScheduledDate
@@ -112,6 +112,12 @@ public struct JobSchedule: MutableCollection, Sendable {
         }
     }
 
+    mutating func setInitialNextDate(after date: Date) {
+        for index in 0..<self.count {
+            self[index].nextScheduledDate = self[index].schedule.setInitialNextDate(after: date) ?? .distantFuture
+        }
+    }
+
     /// AsyncSequence of Jobs based on a JobSchedule
     struct JobSequence: AsyncSequence {
         typealias Element = (job: JobParameters, date: Date)
@@ -141,7 +147,9 @@ public struct JobSchedule: MutableCollection, Sendable {
                 let nextScheduledDate = job.element.nextScheduledDate
                 let timeInterval = nextScheduledDate.timeIntervalSinceNow
                 do {
-                    try await Task.sleep(until: .now + .seconds(timeInterval))
+                    if timeInterval > 0 {
+                        try await Task.sleep(until: .now + .seconds(timeInterval))
+                    }
                     self.jobSchedule.updateNextScheduledDate(jobIndex: job.offset)
                     return (job.element.jobParameters, nextScheduledDate)
                 } catch {
@@ -179,9 +187,7 @@ public struct JobSchedule: MutableCollection, Sendable {
                     date = .now
                 }
                 self.jobQueue.logger.debug("Last scheduled date \(date).")
-                for index in 0..<jobSchedule.count {
-                    jobSchedule[index].nextScheduledDate = jobSchedule[index].schedule.setInitialNextDate(after: date) ?? .distantFuture
-                }
+                jobSchedule.setInitialNextDate(after: date)
             } catch {
                 self.jobQueue.logger.error("Failed to get last scheduled job date.")
             }
diff --git a/Tests/JobsTests/JobSchedulerTests.swift b/Tests/JobsTests/JobSchedulerTests.swift
index 8f087f5..3c563f0 100644
--- a/Tests/JobsTests/JobSchedulerTests.swift
+++ b/Tests/JobsTests/JobSchedulerTests.swift
@@ -167,11 +167,14 @@ final class JobSchedulerTests: XCTestCase {
 
     func testScheduleTimeZone() throws {
         let startDate = ISO8601DateFormatter().date(from: "2021-06-21T21:10:15Z")!
-        var schedule = Schedule.daily(hour: 4, timeZone: .init(secondsFromGMT: 0)!)
+        var schedule = Schedule.daily(hour: 4, timeZone: .init(secondsFromGMT: 7200)!)
         let scheduledDate = try XCTUnwrap(schedule.nextDate(after: startDate))
-        let dateComponents = Calendar.current.dateComponents([.hour], from: scheduledDate)
+        var calendar = Calendar(identifier: .gregorian)
+        calendar.timeZone = .init(secondsFromGMT: 0)!
+
+        let dateComponents = calendar.dateComponents([.hour], from: scheduledDate)
         // check timezone difference is the same as the difference in the schedule
-        XCTAssertEqual(TimeZone.current.secondsFromGMT(), (dateComponents.hour! - 4) * 3600)
+        XCTAssertEqual((dateComponents.hour! - 4) * 3600, -7200)
     }
 
     func testJobSchedule() throws {
@@ -189,9 +192,8 @@ final class JobSchedulerTests: XCTestCase {
         dateFormatter.locale = Locale(identifier: "en_US_POSIX")
         dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss'Z'"
         let startDate = dateFormatter.date(from: "2024-04-14T02:00:00Z")!
-        for jobIndex in schedule.startIndex..<schedule.endIndex {
-            schedule[jobIndex].nextScheduledDate = schedule[jobIndex].schedule.nextDate(after: startDate)!
-        }
+        schedule.setInitialNextDate(after: startDate)
+
         // first two jobs should be Job1
         var job = try XCTUnwrap(schedule.nextJob())
         for _ in 0..<2 {
@@ -214,6 +216,49 @@ final class JobSchedulerTests: XCTestCase {
         XCTAssert(job.element.jobParameters is Job2)
     }
 
+    func testJobScheduledAtSameTimeSequence() async throws {
+        struct Job1: JobParameters {
+            static let jobName = "Job1"
+        }
+        struct Job2: JobParameters {
+            static let jobName = "Job2"
+        }
+        var jobSchedule = JobSchedule([
+            .init(job: Job1(), schedule: .everyMinute(second: 45)),
+            .init(job: Job2(), schedule: .everyMinute(second: 45)),
+        ])
+        jobSchedule.setInitialNextDate(after: .now)
+
+        let job = try XCTUnwrap(jobSchedule.nextJob())
+        jobSchedule.updateNextScheduledDate(jobIndex: job.offset)
+        XCTAssert(job.element.jobParameters is Job1)
+        let job2 = try XCTUnwrap(jobSchedule.nextJob())
+        jobSchedule.updateNextScheduledDate(jobIndex: job2.offset)
+        XCTAssert(job2.element.jobParameters is Job2)
+
+    }
+
+    func testJobScheduledAfterLongWait() async throws {
+        struct Job1: JobParameters {
+            static let jobName = "Job1"
+        }
+        struct Job2: JobParameters {
+            static let jobName = "Job2"
+        }
+        var jobSchedule = JobSchedule([
+            .init(job: Job1(), schedule: .onMinutes([10, 45]))
+        ])
+        jobSchedule.setInitialNextDate(after: .now - 30 * 24 * 60 * 60)
+
+        let job = try XCTUnwrap(jobSchedule.nextJob())
+        // first job scheduled date should be before now
+        XCTAssert(job.element.nextScheduledDate < .now)
+        jobSchedule.updateNextScheduledDate(jobIndex: job.offset)
+        let job2 = try XCTUnwrap(jobSchedule.nextJob())
+        // second job scheduled date should be after now
+        XCTAssert(job2.element.nextScheduledDate > .now)
+    }
+
     func testJobScheduleSequence() async throws {
         struct Job1: JobParameters {
             static let jobName = "Job1"