From 60257ce40b7da20c45c77bbbaa1db19d1c1368b0 Mon Sep 17 00:00:00 2001
From: Jonas Zeiger <jonas@giantswarm.io>
Date: Sun, 17 Mar 2024 23:19:33 +0100
Subject: [PATCH] util.FilterTimeOffs(): function to filter timeOffs

---
 CHANGELOG.md |  4 ++++
 util.go      | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5a5139c..e163dcb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Add `util.FilterTimeOffs()` function
+
 ## [0.3.0] - 2023-07-05
 
 ### Added
diff --git a/util.go b/util.go
index 62285fa..21f73d6 100644
--- a/util.go
+++ b/util.go
@@ -2,6 +2,8 @@ package util
 
 import (
 	"time"
+
+	v1 "github.com/giantswarm/personio-go/v1"
 )
 
 // PersonioDateMax is the maximum representable time.Time value for the Personio API
@@ -22,3 +24,56 @@ func GetTimeIntersection(start1 time.Time, end1 time.Time, start2 time.Time, end
 
 	return endMin.Sub(startMax)
 }
+
+// FilterTimeOffs returns a slice of timeOffs that overlap with the given bounds and optionally matches minimum length and email
+// Specify a minLengthHours of 0 to disable length filtering
+// Specify email as nil to disable email filtering
+func FilterTimeOffs(timeOffs []*v1.TimeOff, start time.Time, end time.Time, minLengthHours float64, email *string) []*v1.TimeOff {
+	var matchedTimeOffs []*v1.TimeOff
+
+	for _, timeOff := range timeOffs {
+
+		timeOffEmail := timeOff.Employee.GetStringAttribute("email")
+		if email != nil && (timeOffEmail == nil || *email != *timeOffEmail) {
+			continue
+		}
+
+		timeOffStart := timeOff.StartDate
+		timeOffEnd := timeOff.EndDate
+		// we need to adjust the wall-clock time according to other fields
+		if timeOff.DaysCount > 1 {
+			if timeOff.HalfDayStart {
+				timeOffStart = timeOffStart.Add(time.Hour * 12)
+			}
+			if timeOff.HalfDayEnd {
+				timeOffEnd = timeOffEnd.Add(time.Hour * 12)
+			} else {
+				timeOffEnd = timeOffEnd.Add(time.Hour * 24)
+			}
+		} else {
+			if timeOff.HalfDayStart && !timeOff.HalfDayEnd {
+				timeOffEnd = timeOffEnd.Add(time.Hour * 12)
+			} else if !timeOff.HalfDayStart && timeOff.HalfDayEnd {
+				timeOffStart = timeOffStart.Add(time.Hour * 12)
+				timeOffEnd = timeOffEnd.Add(time.Hour * 24)
+			} else {
+				timeOffEnd = timeOffEnd.Add(time.Hour * 24)
+			}
+		}
+
+		if minLengthHours > 0 && timeOffEnd.Sub(timeOffStart).Hours() < minLengthHours {
+			// timeOff event too short, ignore
+			continue
+		}
+
+		overlap := GetTimeIntersection(timeOffStart, timeOffEnd, start, end)
+		if overlap <= 0 {
+			// timeOff and bounds don't overlap
+			continue
+		}
+
+		matchedTimeOffs = append(matchedTimeOffs, timeOff)
+	}
+
+	return matchedTimeOffs
+}