From 1d0e862078a9b92e471ddecbc442ff67ba646fd2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E3=83=9E=E3=83=AA=E3=82=A6=E3=82=B9?= <marius@twostairs.co>
Date: Sun, 11 Oct 2020 15:12:41 +0100
Subject: [PATCH] Implemented helpers

---
 z/helpers.go | 100 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 z/helpers.go

diff --git a/z/helpers.go b/z/helpers.go
new file mode 100644
index 0000000..0d38cd4
--- /dev/null
+++ b/z/helpers.go
@@ -0,0 +1,100 @@
+package z
+
+import (
+  "os/user"
+  "regexp"
+  "strconv"
+  "time"
+  "errors"
+)
+
+
+const (
+  TFAbsTwelveHour int = 0
+  TFAbsTwentyfourHour int = 1
+  TFRelHourMinute int = 2
+  TFRelHourFraction int = 3
+)
+
+func TimeFormats() []string {
+  return []string{
+    `^\d{1,2}:\d{1,2}(am|pm)$`, // Absolute twelve hour format
+    `^\d{1,2}:\d{1,2}$`, // Absolute twenty four hour format
+    `^([+-])(\d{1,2}):(\d{1,2})$`, // Relative hour:minute format
+    `^([+-])(\d{1,2})\.(\d{1,2})$`, // Relative hour.fraction format
+  }
+}
+
+func GetCurrentUser() (string) {
+  user, err := user.Current()
+  if err != nil {
+    return "unknown"
+  }
+
+  return user.Username
+}
+
+func GetTimeFormat(timeStr string) (int) {
+  var matched bool
+  var regerr error
+
+  for timeFormatId, timeFormat := range TimeFormats() {
+    matched, regerr = regexp.MatchString(timeFormat, timeStr)
+    if regerr != nil {
+      return -1
+    }
+
+    if matched == true {
+      return timeFormatId
+    }
+  }
+
+  return -1
+}
+
+func RelToTime(timeStr string, ftId int) (time.Time, error) {
+    var re = regexp.MustCompile(TimeFormats()[ftId])
+    gm := re.FindStringSubmatch(timeStr)
+
+    if len(gm) < 4 {
+      return time.Now(), errors.New("No match")
+    }
+
+
+    var hours int = 0
+    var minutes int = 0
+
+    if ftId == TFRelHourFraction {
+      f, _ := strconv.ParseFloat(gm[2] + "." + gm[3], 32)
+      minutes = int(f * 60.0)
+    } else {
+      hours, _ = strconv.Atoi(gm[2])
+      minutes, _ = strconv.Atoi(gm[3])
+    }
+
+    var t time.Time
+
+    switch gm[1] {
+    case "+":
+      t = time.Now().Local().Add(time.Hour * time.Duration(hours) + time.Minute * time.Duration(minutes))
+    case "-":
+      t = time.Now().Local().Add((time.Hour * time.Duration(hours) + time.Minute * time.Duration(minutes)) * -1)
+    }
+
+    return t, nil
+}
+
+func ParseTime(timeStr string) (time.Time, error) {
+  tfId := GetTimeFormat(timeStr)
+
+  switch tfId {
+  case TFAbsTwelveHour:
+    return time.Parse("3:04pm", timeStr)
+  case TFAbsTwentyfourHour:
+    return time.Parse("15:04", timeStr)
+  case TFRelHourMinute, TFRelHourFraction:
+    return RelToTime(timeStr, tfId)
+  default:
+    return time.Now(), errors.New("No match")
+  }
+}