Issue time estimate, meaningful time tracking (#23113)

Redesign the time tracker side bar, and add "time estimate" support (in "1d 2m" format)

Closes #23112

---------

Co-authored-by: stuzer05 <stuzer05@gmail.com>
Co-authored-by: Yarden Shoham <hrsi88@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

modules/util/time_str.go

@@ -0,0 +1,85 @@
+// Copyright 2024 Gitea. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+	"sync"
+)
+
+type timeStrGlobalVarsType struct {
+	units []struct {
+		name string
+		num  int64
+	}
+	re *regexp.Regexp
+}
+
+// When tracking working time, only hour/minute/second units are accurate and could be used.
+// For other units like "day", it depends on "how many working hours in a day": 6 or 7 or 8?
+// So at the moment, we only support hour/minute/second units.
+// In the future, it could be some configurable options to help users
+// to convert the working time to different units.
+
+var timeStrGlobalVars = sync.OnceValue[*timeStrGlobalVarsType](func() *timeStrGlobalVarsType {
+	v := &timeStrGlobalVarsType{}
+	v.re = regexp.MustCompile(`(?i)(\d+)\s*([hms])`)
+	v.units = []struct {
+		name string
+		num  int64
+	}{
+		{"h", 60 * 60},
+		{"m", 60},
+		{"s", 1},
+	}
+	return v
+})
+
+func TimeEstimateParse(timeStr string) (int64, error) {
+	if timeStr == "" {
+		return 0, nil
+	}
+	var total int64
+	matches := timeStrGlobalVars().re.FindAllStringSubmatchIndex(timeStr, -1)
+	if len(matches) == 0 {
+		return 0, fmt.Errorf("invalid time string: %s", timeStr)
+	}
+	if matches[0][0] != 0 || matches[len(matches)-1][1] != len(timeStr) {
+		return 0, fmt.Errorf("invalid time string: %s", timeStr)
+	}
+	for _, match := range matches {
+		amount, err := strconv.ParseInt(timeStr[match[2]:match[3]], 10, 64)
+		if err != nil {
+			return 0, fmt.Errorf("invalid time string: %v", err)
+		}
+		unit := timeStr[match[4]:match[5]]
+		found := false
+		for _, u := range timeStrGlobalVars().units {
+			if strings.ToLower(unit) == u.name {
+				total += amount * u.num
+				found = true
+				break
+			}
+		}
+		if !found {
+			return 0, fmt.Errorf("invalid time unit: %s", unit)
+		}
+	}
+	return total, nil
+}
+
+func TimeEstimateString(amount int64) string {
+	var timeParts []string
+	for _, u := range timeStrGlobalVars().units {
+		if amount >= u.num {
+			num := amount / u.num
+			amount %= u.num
+			timeParts = append(timeParts, fmt.Sprintf("%d%s", num, u.name))
+		}
+	}
+	return strings.Join(timeParts, " ")
+}