Generate invoice PDFs

1 files changed, 108 insertions, 0 deletions

diff --git a/internal/reports/daterange.go b/internal/reports/daterange.go
new file mode 100644
index 0000000..3478615
--- /dev/null
+++ b/internal/reports/daterange.go
@@ -0,0 +1,108 @@
+package reports
+
+import (
+	"fmt"
+	"strings"
+	"time"
+)
+
+type DateRange struct {
+	Start time.Time
+	End   time.Time
+}
+
+func ParseDateRange(dateStr string) (DateRange, error) {
+	dateStr = strings.TrimSpace(dateStr)
+	now := time.Now().UTC()
+
+	// Check for predefined ranges (case-insensitive)
+	lowerDateStr := strings.ToLower(dateStr)
+	switch lowerDateStr {
+	case "last week":
+		return getLastWeek(now), nil
+	case "last month":
+		return getLastMonth(now), nil
+	}
+
+	// Check for custom date range format: "YYYY-MM-DD to YYYY-MM-DD"
+	if strings.Contains(dateStr, " to ") {
+		return parseCustomDateRange(dateStr)
+	}
+
+	return DateRange{}, fmt.Errorf("unsupported date range: %s (supported: 'last week', 'last month', or 'YYYY-MM-DD to YYYY-MM-DD')", dateStr)
+}
+
+func parseCustomDateRange(dateStr string) (DateRange, error) {
+	parts := strings.Split(dateStr, " to ")
+	if len(parts) != 2 {
+		return DateRange{}, fmt.Errorf("invalid date range format: expected 'YYYY-MM-DD to YYYY-MM-DD'")
+	}
+
+	startStr := strings.TrimSpace(parts[0])
+	endStr := strings.TrimSpace(parts[1])
+
+	// Parse start date
+	startDate, err := time.Parse("2006-01-02", startStr)
+	if err != nil {
+		return DateRange{}, fmt.Errorf("invalid start date '%s': expected YYYY-MM-DD format", startStr)
+	}
+
+	// Parse end date
+	endDate, err := time.Parse("2006-01-02", endStr)
+	if err != nil {
+		return DateRange{}, fmt.Errorf("invalid end date '%s': expected YYYY-MM-DD format", endStr)
+	}
+
+	// Validate that start date is before or equal to end date
+	if startDate.After(endDate) {
+		return DateRange{}, fmt.Errorf("start date '%s' must be before or equal to end date '%s'", startStr, endStr)
+	}
+
+	// Convert to UTC and set times appropriately
+	// Start date: beginning of day (00:00:00)
+	startUTC := time.Date(startDate.Year(), startDate.Month(), startDate.Day(), 0, 0, 0, 0, time.UTC)
+	
+	// End date: end of day (23:59:59.999999999)
+	endUTC := time.Date(endDate.Year(), endDate.Month(), endDate.Day(), 23, 59, 59, 999999999, time.UTC)
+
+	return DateRange{
+		Start: startUTC,
+		End:   endUTC,
+	}, nil
+}
+
+func getLastWeek(now time.Time) DateRange {
+	// Find the start of current week (Monday)
+	weekday := int(now.Weekday())
+	if weekday == 0 { // Sunday
+		weekday = 7
+	}
+	
+	// Start of current week
+	currentWeekStart := now.AddDate(0, 0, -(weekday-1)).Truncate(24 * time.Hour)
+	
+	// Last week is the week before current week
+	lastWeekStart := currentWeekStart.AddDate(0, 0, -7)
+	lastWeekEnd := currentWeekStart.Add(-time.Nanosecond)
+	
+	return DateRange{
+		Start: lastWeekStart,
+		End:   lastWeekEnd,
+	}
+}
+
+func getLastMonth(now time.Time) DateRange {
+	// Start of current month
+	currentMonthStart := time.Date(now.Year(), now.Month(), 1, 0, 0, 0, 0, time.UTC)
+	
+	// Last month start
+	lastMonthStart := currentMonthStart.AddDate(0, -1, 0)
+	
+	// Last month end (last nanosecond of last month)
+	lastMonthEnd := currentMonthStart.Add(-time.Nanosecond)
+	
+	return DateRange{
+		Start: lastMonthStart,
+		End:   lastMonthEnd,
+	}
+}
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