From 96ce320e4dc333d074af28cb11b50f31437d6eab Mon Sep 17 00:00:00 2001
From: Ronni Skansing <rskansing@gmail.com>
Date: Thu, 4 Sep 2025 10:28:55 +0200
Subject: [PATCH] template function for date

Signed-off-by: Ronni Skansing <rskansing@gmail.com>
---
 backend/service/templateService.go            | 50 ++++++++++++++++++-
 .../src/lib/components/editor/Editor.svelte   | 44 +++++++++++++++-
 2 files changed, 91 insertions(+), 3 deletions(-)

diff --git a/backend/service/templateService.go b/backend/service/templateService.go
index b02268c..3d0cad0 100644
--- a/backend/service/templateService.go
+++ b/backend/service/templateService.go
@@ -8,6 +8,7 @@ import (
 	"io"
 	"math/rand"
 	"strings"
+	"time"
 
 	"github.com/go-errors/errors"
 	"github.com/google/uuid"
@@ -265,8 +266,9 @@ func (t *Template) newTemplateDataMap(
 		// sender fields
 		"From": mailHeaderFrom,
 		// general fields
-		"BaseURL":      baseURL,
-		"URL":          url,
+		"BaseURL": baseURL,
+		"URL":     url,
+
 		"APIKey":       "",
 		"CustomField1": "",
 		"CustomField2": "",
@@ -420,6 +422,15 @@ func TemplateFuncs() template.FuncMap {
 		},
 		"randAlpha": RandAlpha,
 		"qr":        GenerateQRCode,
+		"date": func(format string, offsetSeconds ...int) string {
+			offset := 0
+			if len(offsetSeconds) > 0 {
+				offset = offsetSeconds[0]
+			}
+			targetTime := time.Now().Add(time.Duration(offset) * time.Second)
+			goFormat := convertDateFormat(format)
+			return targetTime.Format(goFormat)
+		},
 	}
 }
 
@@ -525,3 +536,38 @@ func (q *QRHTMLWriter) Close() error {
 	}
 	return nil
 }
+
+// convertDateFormat converts readable date format (YmdHis) to Go's reference format
+func convertDateFormat(dateFormat string) string {
+	goFormat := dateFormat
+
+	// year formats
+	goFormat = strings.ReplaceAll(goFormat, "Y", "2006") // 4-digit year
+	goFormat = strings.ReplaceAll(goFormat, "y", "06")   // 2-digit year
+
+	// month formats
+	goFormat = strings.ReplaceAll(goFormat, "m", "01")      // 2-digit month
+	goFormat = strings.ReplaceAll(goFormat, "n", "1")       // month without leading zero
+	goFormat = strings.ReplaceAll(goFormat, "M", "Jan")     // short month name
+	goFormat = strings.ReplaceAll(goFormat, "F", "January") // full month name
+
+	// day formats
+	goFormat = strings.ReplaceAll(goFormat, "d", "02") // 2-digit day
+	goFormat = strings.ReplaceAll(goFormat, "j", "2")  // day without leading zero
+
+	// hour formats
+	goFormat = strings.ReplaceAll(goFormat, "H", "15") // 24-hour format
+	goFormat = strings.ReplaceAll(goFormat, "h", "03") // 12-hour format
+	goFormat = strings.ReplaceAll(goFormat, "G", "15") // 24-hour without leading zero (Go doesn't support this exactly)
+	goFormat = strings.ReplaceAll(goFormat, "g", "3")  // 12-hour without leading zero
+
+	// minute and second formats
+	goFormat = strings.ReplaceAll(goFormat, "i", "04") // minutes
+	goFormat = strings.ReplaceAll(goFormat, "s", "05") // seconds
+
+	// am/pm formats
+	goFormat = strings.ReplaceAll(goFormat, "A", "PM") // uppercase AM/PM
+	goFormat = strings.ReplaceAll(goFormat, "a", "pm") // lowercase am/pm
+
+	return goFormat
+}
diff --git a/frontend/src/lib/components/editor/Editor.svelte b/frontend/src/lib/components/editor/Editor.svelte
index 34cdd91..a3bd88b 100644
--- a/frontend/src/lib/components/editor/Editor.svelte
+++ b/frontend/src/lib/components/editor/Editor.svelte
@@ -59,7 +59,8 @@
 			{ label: 'URL as QR HTML', text: '{{qr .URL 4}}' },
 			{ label: 'URL escape', text: '{{urlEscape "content" }}' },
 			{ label: 'Random alphanumeric', text: '{{randAlpha 8}}' },
-			{ label: 'Random number', text: '{{randInt 1 4}}' }
+			{ label: 'Random number', text: '{{randInt 1 4}}' },
+			{ label: 'Date', text: '{{date "Y-m-d H:i:s" 0}}' }
 		]
 	};
 
@@ -226,6 +227,19 @@
 				return result;
 			});
 		}
+
+		// handle date function with format and optional offset
+		if (text.includes('{{date')) {
+			const r = /{{date\s+"([^"]+)"\s*(-?\d+)?}}/g;
+			text = text.replace(r, (match, format, offset) => {
+				const currentTime = new Date();
+				const offsetSeconds = offset ? parseInt(offset, 10) : 0;
+				const targetTime = new Date(currentTime.getTime() + offsetSeconds * 1000);
+
+				return formatDate(targetTime, format);
+			});
+		}
+
 		switch (contentType) {
 			case 'domain':
 				return text.replaceAll('{{.BaseURL}}', _baseURL);
@@ -320,6 +334,34 @@
 		}
 	};
 
+	// formatDate converts readable date format (YmdHis) to formatted date string
+	const formatDate = (date, format) => {
+		const pad = (num, size = 2) => num.toString().padStart(size, '0');
+
+		const replacements = {
+			Y: date.getFullYear(), // 4-digit year
+			y: date.getFullYear().toString().slice(-2), // 2-digit year
+			m: pad(date.getMonth() + 1), // 2-digit month
+			n: date.getMonth() + 1, // month without leading zero
+			d: pad(date.getDate()), // 2-digit day
+			j: date.getDate(), // day without leading zero
+			H: pad(date.getHours()), // 24-hour format
+			G: date.getHours(), // 24-hour without leading zero
+			h: pad(date.getHours() % 12 || 12), // 12-hour format
+			g: date.getHours() % 12 || 12, // 12-hour without leading zero
+			i: pad(date.getMinutes()), // minutes
+			s: pad(date.getSeconds()), // seconds
+			A: date.getHours() >= 12 ? 'PM' : 'AM', // uppercase AM/PM
+			a: date.getHours() >= 12 ? 'pm' : 'am' // lowercase am/pm
+		};
+
+		let result = format;
+		for (const [key, value] of Object.entries(replacements)) {
+			result = result.replaceAll(key, value.toString());
+		}
+		return result;
+	};
+
 	let isDetailsVisible = $$slots.default;
 </script>