Initial implementation

internal/models/event.go

@@ -0,0 +1,37 @@
+// Package models defines the core data structures for the application.
+package models
+
+import "time"
+
+// Event represents a calendar event.
+type Event struct {
+	ID          string
+	Title       string
+	Description string
+	Start       time.Time
+	End         time.Time
+	AllDay      bool
+	Location    string
+	Source      EventSource
+}
+
+// EventSource indicates where an event originated from.
+type EventSource string
+
+const (
+	SourceLocal  EventSource = "local"
+	SourceCalDAV EventSource = "caldav"
+)
+
+// IsOnDate checks if the event occurs on the given date.
+func (e *Event) IsOnDate(date time.Time) bool {
+	eventDate := e.Start.Truncate(24 * time.Hour)
+	checkDate := date.Truncate(24 * time.Hour)
+
+	if e.AllDay {
+		endDate := e.End.Truncate(24 * time.Hour)
+		return !checkDate.Before(eventDate) && checkDate.Before(endDate)
+	}
+
+	return eventDate.Equal(checkDate)
+}